Alkali-Silica Reactivity in Concrete
Final Report March 29, 2005
WSDOT Agreement Number Y-8694
KBA Project 0312-02
KBA, Inc. Construction Management
KBA Project 0312-20
This report presents the results of investigations conducted by the WDSOT Materials staff under
the coordination and direction of Robert H. Gietz PE of KBA Inc. Construction Management.
These studies took place starting in April 2004 under study agreement between the parties. This
agreement was modified near the end of 2004 to include preparation of a final report.
The study agreement enumerated several tasks, each of which is presented in a separate section.
The study tasks were:
Task 100: Study Existing Structures, Pavement And Standards, which further included
100a Background Of Current Standards
100b Study Of Materials History Of Cement And Aggregates
100c Investigate And Obtain Project Data
Task 200 Review Recent Pavement Or Structure Construction with two subtasks:
200a Identify Candidate Projects For Field Examination
200b Develop Summary Of Construction Data
Task 300 Prepare Study Plan
Task 400 Prepare A Final Report to include:
400a Documentation Of Test Results
400b Recommended Revisions To Standards And Specifications
Conduct of this sort of study depends largely on access and manipulation of bases of existing
information. WSDOT staff in the Material and Bridge Condition sections was most co-operative
in responding to request for copying and selection of necessary information. Contractor and
supplier representatives in the Ready Mix industry and the cement and fly ash venues provided
abundant test results and materials source reports that expanded the knowledge base and were
most beneficial in assessing the status of materials in current and historical use.
At the basic working level, there was outstanding personal involvement in this project. This
project involved a somewhat extended span of time, pending receipt of final test reports and
throughout this period, efforts were always available to meet drop-in requests for comments and
consultation. Particular appreciation is accorded to Jeanne Andresasson, Don Brouillard, and Jeff
SUBTASK SUMMARIES AND RECOMMENDATIONS
100a Background of current Standards
This task began by surveying current standards of adjacent agencies. The agencies contacted
• Western Federal Land Highway Division (WFLHD)
• Oregon Department of Transportation (ODOT)
• Idaho Department of Public Transportation (IDPT)
• Canadian Standards Association (CSA)
Current standards and specifications for concrete materials and Portland cement mixes were
researched for the states of Oregon and Idaho, and for aggregate practice for the Western
Federal Lands Highway Division (FHWA Direct) and for concrete mix review procedure in
Canada. The media involved included examination of existing documents, published
standard reports and personal discussions with representatives. WSDOT’s practice and status
of approved concrete sources was reviewed. The related reference standards and procedures
with some brief comments are included on the following page (Table 1, Summary of test
Agency Specifications And Standards
OREGON Telephone response from Keith Johnston of the ODOT Construction Office
indicated that there are no special measures in place for consideration of ASR potential for
ODOT structural concrete. Perception is that increasing use of fly ash by concrete producers
combined with the historically low alkali content of locally available cements effectively reduces
the likelihood of ASR occurrence.
IDAHO: IIDPT incorporated requirements for mitigation of ASR in their 2004
specifications. Based on the depletion of previous aggregate sources and identification of greater
reaction potential in new sources, a program of agency and industry training and implementation
was concluded in April of 2004 to implement these provisions. The reference standard is a
finding of greater than 0.10% expansion measured by AASHTO T 303. Mitigation is directed
toward the use of fly ash addition. Idaho has used AASHTO T 299 (Uranyl Acetate) for field
WFLHD: (Western Federal Lands Highway Division, FHWA) Thru conversation with Brad
Neitzke of the Vancouver office, reports that they deal with ASR in proposed aggregate thru the
provisions of AASHTO M 80 for coarse aggregate. Optional provisions provide for ASTM C
1260 screening and follow-up for definitive mitigation by evaluation under ASTM C 1293 or
petrographic analysis. There is not an urgent concern with ASR from the Agency and not a
rigorous imposition of the review requirements. They are aware that ASR deterioration has
occurred on several FHWA-constructed structures in the vicinity.
Table 1:Summary of Test methods
This summary of current test methods and procedures may be useful to compare
and reference the various standard methods that are discussed in this report.
ASTM C 289 Potential ASR of Aggregates chemical method
• Rapid chemical analysis
• May fail to detect long term reactivity
ASTM C 227 Potential ASR of Aggregates Mortar Bar Method
• Extended time period
AASHTO T 299 Rapid identification of Alkali Silica Reaction products in concrete (Uranyl
(LANL) test Los Alamos National Laboratory (Sodium/Cobaltnitrite-Rhodamine B)
commercially provided by James Instruments as the ASR Detect test
ASTM C 295 Petrographic analysis of Aggregates for Concrete
ASTM C 441 Effectiveness of Mineral Admixtures in reducing Alkali Aggregate
ASTM C 856 Petrographic Analysis of Hardened concrete
ASTM C 1260 Potential Alkali Reactivity of Aggregates Mortar Bar Method
(AASHTO T 303) Accelerated Mortar Bar Test (AMBT)
• 14 day results, High alkali solution, elevated temperature
• Use to classify aggregates as innocuous
• Confirm reactivity by C1293
• Can check mitigation by admixtures (fly ash)
• No evaluation of low alkali cement
ASTM C 1293 Determination of Length Change due to ASR (Concrete Prism Test (CPT)
• Extended test, up to 1 year
• Can evaluate admixtures,
• Uses high alkali cement (5.25 kg/m3: 8.85 #/yd3)
Thomas & Innis report, 1999, compared results from 70 aggregate/cement combinations tested
by C1260 & C1293. 5 of the 70- passed the mortar bar test (C1260) and failed the concrete
prism test (C1293) 51 of the 70 combinations achieved the same result (either pass or fail) in
both test methods 14 failed the mortar bar tests (C1260, expansion greater than 0.10%) but
passed the concrete prism test (C 1293, expansion less than 0.04%. Of these, 8 are of
controversial nature from sand in Kansas.
CANADA Information on Canadian practice with regard to AAR (Alkali-Aggregate
Reaction, in their terms) was obtained from the report on CSA A23.2-27A (2000) presented to
the 11th International Conference on Alkali Aggregate Reaction (ICAR). Under this standard the
reactivity potential of an aggregate source is assessed by laboratory methods. This is combined
with a risk analysis approach based on the structural and environmental conditions of a particular
structure to determine the mitigation, measures appropriate to the defined risk. As a part of the
preventive measures considered under this standard, the level of alkalis contributed by the
Portland cement is considered. For certain exposures, maximum threshold alkali levels of either
3.0 or 2.4 kg/m3 are established. By way of reference the design level of alkalis for ASTM C
1293 samples is 5.25 kg/m3.
(An approximate conversion factor multiplier of 1.679 would yield corresponding limits in the
customary standards system of 5.0 or 4.03 pounds per cubic yard. Further extending this
comparison, a cement content of 658 pounds per cubic yards employing low-alkali cement
(alkalis less than 0.60%) would have an alkali content of 3.95 pounds per cubic yard). From this
it was apparent that the expected alkali content for nominal material from past and current
Washington Highway construction would be less than one-half the critical level, and below some
of the screening levels proposed in the current Canadian standards.
Current Specifications: WSDOT initiated concern with ASR in the 2000 Standard Specifications
and further amended the 2002 edition. This was an outgrowth of SHRP and the related
development of the rapid test for reactivity (Accelerated Mortar Bar Test: AMBT)(ASTM C
1260, technically identical to AASHTO T-303)). WSDOT specification language implements
approximately the SHRP developed AASHTO guide specifications and sets initial conditions for
aggregate acceptance based on AASHTO T 303 14-day results. There are provisions for
mitigation and further evaluation and further references to possible use of low-alkali cement.
Mitigation measures thru incorporation of fly ash may be approved based on ASTM C-1260
however low-alkali cement is not subject to this evaluation and must rely on the Concrete Prism
Test (CPT) ASTM C-1293, long term testing. Petrographic Analysis (ASTM C 295) may be
provided to negate reactivity identified by ASTM C 1260 (AMBT)
WSDOT Historical Practice. Prior to the inception of the SHRP, WSDOT historically used
ASTM C-289 chemical tests. This test is recognized to deal most effectively with near term
reactivity and not detect long-term reaction. . Previous use of ASTM C-289 had indicated
generally low or no incidence of reactivity. This standard was recently used on selected
occasions such as design of SR 504, Mt St Helens highway. On that design project it was used
by the geotechnical consultant and accepted by WSDOT to qualify possible aggregate sources
for the reconstruction involved. ASTM C-1260, the accelerated mortar bar reactivity test, itself a
modification of ASTM C 227, measures reactive potential but is acknowledged to provide
possible false positives for reactivity and proposes further evaluation as to true nature of
reactivity when potential problems are disclosed.
Comments On WSDOT Current Standards
Review of related documents discloses that the current WSDOT practice, in which Petrographic
Analysis (ASTM C 295) is used to negate the results of ASTM C 1260 testing, is not in
agreement with the intent of the hierarchy of testing. The AASHTO guide specification
(Referring to the version identified as 8/22/2000) implies that the relative considerations are:
Service History, Petrographic Analysis (to identify potential reactivity); Confirming mortar bar
or concrete prism tests. As presently written WSDOT allows ASTM C 295 results, when found
below the defined compositional limits, to be used to negate reactivity discovered in ASTM C
1260 or C 1293 testing. Reading of the related test methods and other reports seems to indicate
that this is not in agreement with the apparent precedence of tests. Several references stress the
use of multiple tests to identify potentially reactive aggregates. Use of petrographic analysis
(ASTM C295) results to set aside identified reactivity would seem to conflict with this principle.
A current copy of the AASHTO guide specification was obtained from the AASHTO website. It
contains a flow chart, which seems to confirm the use of petrographic analysis as a preliminary
measure, which may be an indicator of the need for further testing to define the reactivity of a
Comments on Test methods
ASTM C1260 (AASHTO T 303) accelerates the reaction though an increased concentration of
alkalis in the surrounding solution and an elevated temperature. The required temperature, (80C)
induces thermal expansion in the test specimens and mandates time critical testing of the bars to
minimize thermal contraction during the measuring process. There are proposals for modifying
this test method to enhance testing precision and, possibly, differentiate the degrees of reactivity
more clearly. One such proposal evaluated a range of temperatures and solution concentrations.
There seemed to be a general trend to better differentiate degree of reactivity with lower
temperature and/or lower solution concentration. The trade-off occurred in that a longer test
time is required to generate final results (up to 56 days) Reference for this is ICAR 11th
International Conference Report.
In considering the possible use of low-alkali cement, effort was made to define the test method
and procedure to measure the effective mitigation. ASTM C 1260 employs a high alkalinity
solution to induce the reactivity, independent of the nature of the particular cement utilized.
ASTM C 1293 directs that a specific content of high alkali cement be used for the long-term
evaluation. It could be inferred that substitution of a lesser alkali content would be acceptable.
However, there is no evidence that such a measure is contemplated in the standard. The
AASHTO Guide specification contains the only procedure for verifying effectiveness of low
alkali cement that has been located to date. This reference calls for use of ASTM C 441. Upon
examination that procedure does contemplate its use. However ASTM C 441 defines the
aggregate for use as a highly reactive Pyrex glass, rather than a candidate specific material.
ASTM C 441, by its title, is a measure of the effectiveness of pozzolanic material in reducing
reactivity and does this by comparison with a reference material and the glass aggregate.
Considering a typical Portland cement content of 0.60% equivalent alkalis, a typical mix
employed by WSDOT would have approximately 2.5-kg/m3 alkali content, thus meeting the
requirement for moderate protection against ASR as defined in the Canadian Practice Standard.
In common, with other agencies, WSDOT does not have specific procedures to consider the use
of low alkali cement as a mitigation measure. The rapid test, ASTM C1260 and its AASHTO
counterpart T 303 are not capable of measuring the effect of cement alkali content alone.
Mitigation thru cement alkali reduction requires use of other procedures such as ASTM C227,
ASTM C441 or ASTM C 1293.
WSDOT determined to not use the Rapid Field Test For Identification Of ASR (AASHTO
T299). This determination was made based on concern over handling of the reagent materials
involved. An alternate procedure, known as the LANL test or ASR Detect test has since been
developed. During the present study, test kits were obtained for this ASR Detect test developed
by the Los Alamos National Laboratory. It permits observation under natural light and uses less
hazardous materials as reagents. Trial use was restricted to indoor testing in the Chemical
Laboratory on core samples taken from structures. It is relatively easy to perform and interpret.
Field preparation would require production of a fresh concrete surface by removal of about ½
inch of concrete. Cost is reasonable with a kit stated to be capable of ten individual tests costing
100b Study Of Materials History Of Cement And Aggregates
Cement And Fly Ash Supply History
Significance of Cement and Fly Ash composition. Three elements are identified as necessary for
the formation of alkali-silica reactive gel and the consequent deterioration of concrete. These
elements are: reactive aggregate, available alkalis for reaction, and moisture content sufficient to
drive the reaction. Each of these components has it’s own threshold conditions. Some researchers
have proposed that the cement alkalis below. 0.60% expressed as equivalent NaO is in the
benevolent range. Reactive silica has been characterized in the past by use of ASTM C 289
evaluating the soluble components in an aggregate sample. Further characterization of the
aggregate composition is the goal of the petrographic analysis by ASTM C 295. ASTM C1260
subjects the candidate aggregate to an exposure of extreme alkalinity and has been utilized to
evaluate the performance of mitigation measures other than low-alkali cements.
Moisture levels have been expressed in terms of the relative humidity of the concrete involved.
A threshold of 80%, which could be considered as a proportion of saturation, has been
considered as the necessary level to sustain the reaction process. With respect to pavements, a
level of 80% relative humidity has been found with relative consistency when considering
pavement below the upper three inches. Drying from air exposure occurs in this upper portion
but the saturation level for reaction would generally exist at the greater depth.
Cementitious materials have their own characteristics as to potential participation in the process.
Cement is usually considered based on its content of NaO equivalent alkalis. The specification
limits of 0.60% are considered to identify the limits below which the reaction is unlikely. A
second consideration is the volumetric proportion of alkalis (from all sources) present in the
concrete. While the methods of identifying the aggregates contribution to the composite value
are somewhat variable, a value of 4.5 kg/m3 (7.55 #/cy.) has been proposed with a lower limit of
3.0 kg/m3 (5.0 #/cy as a control that might serve to largely preclude reactive deterioration .In
studying performance of concrete in ASTM C 1293, Thomas (1992) found that a limit of 3.0
kg/m3 held expansion below 0.04% even at two years duration.
In characterizing total cementitious materials, some researchers have excluded the alkalis
contained in the fly ash component of a designed mix. This also touches on the aspect that fly
ash’s exact contribution to the reaction mitigation scheme is not totally understood. It has been
hypothesized that fly ash acts to bind alkalis and prevent their progress into the pore water and
thus inhibits the reaction deterioration. From a compositional standpoint, the total and available
alkalis in the fly ash are of interest. A second compositional factor in the performance of fly ash
as a mitigating agent is the lime (CaO) content. From the stand point of this parameter fly ash
has been separated into three subclasses: F, with CaO below 8.0%, CI, CaO content 8-20% and
CH with CaO above 20%. In evaluating mitigating performance it has been found that larger
proportions of ash are required when the CaO content is greater. In the research examined no
CaO content limits have been suggested relative to degree of mitigation. The higher addition
proportions required for higher CaO contents do have a self-limiting aspect in that the overall
cementitious content becomes excessive to good mix design as the fly ash content increases
beyond a nominal limit. In practical terms 25% fly ash seems a maximum addition providing
mitigation of expansion while retaining satisfactory mix performance. The source of this information
was a study reported in Cement and Concrete Research: “The effect of fly ash composition on the expansion of
concrete due to alkali-silica reaction, Medhat H. Shehata and Michale D.A Thomas, Cement and Concrete Research,
Vol. 30. 2000, p 1063-1072
WSDOT Cement and Fly Ash Source production records.
Records were requested from each of the suppliers and evaluated to characterize the alkali
content of cementitious materials (Portland cement and fly ash) that have been furnished over
time. Table I, “Cementitious Materials, Alkalis Summary” presents information compiled from
existing test reports. The tabulated values for each source and product are: average, “95% level”
and Standard deviation. In tabulated information, the maximum reported equivalent alkali
content is also included.
In analyzing these sources it was proposed to consider the variability as well as the nominal
average composition. Towards this end an index was proposed as the “95% limit”, which
corresponds to the upper 95th percentile of the cementitious materials’ alkalis. This is derived
from the computed average value plus two standard deviations. This sort of an index could be
useful to establish a “substantial conformance” measure for a set of results.
It is of interest that in several cases, this “95% limit” exceeds the maximum reported value for
the particular source. This raises the question as to the value of the proposed limit and further
indicates some anomaly in the data reported. Based on a superficial inspection, it appears that
several sets of reported information include a small number of uncharacteristically low values. It
would take more disciplined statistical analysis to establish the exact nature of the distribution
involved, but it appears that the assumption of normal distribution inherent in the application of
analysis may not in fact be warranted. The cement test information may include some values
which could be excluded by an ‘outlier’ test or have evidence of a skewed, non-normal
distribution. Discussion of this condition with Chief Chemist Jeanne Andreasson raises the
possibility that these unusually low values could be due to incorrect laboratory test procedures.
Cementitious Materials Sources
Recent production data was obtained for a number of the suppliers currently providing Portland
cement. This was combined with information from test information in the Materials Laboratory
for material sampled on projects under the former cement acceptance program. The property of
interest is the equivalent alkalis. These historical records do not afford as comprehensive picture
of the generally available material as does the supplier information however it does reflect that
which was supplied to WSDOT projects. In this table, data from earlier years was selected
corresponding to the construction dates of the structures considered for field evaluation.
The historical records of specifications for Portland cement, by WSDOT (WSDH prior to 1977)
were examined. The available standards show a limit of 0.75% on equivalent alkalis first
appeared in the 1948 standards as amended in 1953. The inclusion of a maximum limit of 0.60%
maximum for materials designated as low-alkali first appears in the 1957 version.
As contract information was developed for the sites of particular interest, cement test data for the
source and contract year was extracted from the Laboratory records and is included in the
Cementitious Materials Alkalis Summary (Table 2) as well. Specific source information,
extracted from contract records is contained later in this report for each individual field site. No
cement chemistry information was found for the earlier jobs studied. While the average
equivalent alkali contents seem roughly similar over the time period involved (1962 to present),
the reported/recorded maximum values are greater for the earlier data, particularly prior to 1970.
and back to about 1962. Earlier information indicates greater variability as evidenced by greater
standard deviation. There are earlier laboratory records of cement testing which go back to
approximately 1940. Particularly in the earlier records, sources are not correlated directly to
existing plants and may only represent a portion of production since in earlier times WSDOT
restricted cement use to only type 2. However quick examination of random records in this mass
of data does not indicate that alkali levels exceeded the 0.60% required for classification as low-
alkali product. A number of reports indicate equivalent alkalis in the 0.40 to 0.50% range
Considering that the most recent information is based on large amounts of production testing by
current suppliers, it confirms that an ample supply of cement meeting the low-alkali
requirements is available. This will have bearing on the further recommendations for
specification revisions and procedural changes as a part of this study.
Fly ash supplies
WSDOT customarily receives fly ash from two principal suppliers: ISG Resources and Boral
Materials. ISG has an established production and supply from two locations: the Centralia
Generation plant in West Central Washington and the Bridger plant in southwestern Wyoming.
Boral Materials furnishes ash from the Boardman Oregon. Facility.
With respect to the fly ash, the properties of interest were CaO level, total alkalis and available
alkalis. In specifying Pozzolanic materials under AASHTO M 295, WSDOT has incorporated
the supplementary limiting chemical composition limits from section 6.1, table 2. The current
sources are approaching and in some cases exceeding these limiting values. Bearing in mind that
the intent of this inclusion is the reduction of possible alkali-silica reaction, it would be feasible
to attain this same end by demonstrating performance instead. The requirements of ASTM C
311, which in turn references ASTM test method C 441 could be considered.
TABLE 2 CEMENTITIOUS MATERIALS ALKALI SUMMARY
PRODUCER LOCATION PRODUCT YEAR # tests Average Std Dev 95% level Maximum
Ideal Type II 1962 5 0.596 0.089 0.75
Kaiser Type II 1963 28 0.520 0.100 0.720* 0.69
Lone Star Type II 1963 42 0.490 0.210 0.910* 0.72
Permanente Kaiser:Cal Type II 1966 33 0.438 0.080 0.597* 0.52
Permanente Kaiser: Bel Type II 1966 33 0.442 0.063 0.568 0.66
Kaiser Type II 1970 7 0.402 0.107 0.51
Lone Star Type II 1970 4 0.405 0.42
Columbia Type II 1970 19 0.387 0.084 0.555* 0.51
Ideal Type II 1970 19 0.429 0.065 0.559* 0.51
Lehigh Type II 1970 6 0.530 0.093 0.71
Ideal All 1981 39 0.440 0.084 0.608* 0.58
Lone Star II & III 1982 41 0.553 0.081 0.714 0.75
Ash Grove Seattle Type I 2002 230 0.510 0.060 0.630 0.67
Ash Grove Durkee Type II-V 2002 182 0.479 0.021 0.521 0.53
Ash Grove Durkee Type I- II 2002 360 0.519 0.033 0.585 0.59
Ash Grove Seattle Type I 2003 178 0.470 0.060 0.590 0.60
Ash Grove Durkee Type II-V 2003 156 0.480 0.020 0.520 0.52
Ash Grove Durkee Type I- II 2003 371 0.500 0.030 0.560 0.59
Ash Grove Durkee Type II-V 2003 3 0.383 0.55
Ash Grove Seattle Type I 2004 61 0.530 0.040 0.61 0.66
Ash Grove Durkee Type II-V 2004 7 0.493 0.57
Ash Grove Durkee Type II-V 2004 86 0.525 0.023 0.571 0.58
Lehigh Bellingham Type I-II 1994-2004 256 0.450 0.050 0.560 0.57
Lehigh Delta BC Type I-II 1995-2004 1786 0.450 0.050 0.550* 0.50
Lehigh Bellingham Type III 1995-2004 224 0.460 0.050 0.550 0.58
Onoda Type I 2001-2004 37 0.557 0.026 0.609* 0.59
Lafarge Seattle Type I SM) 2002-2003 5 0.462 0.53
Lafarge Richmond BC Type I-II 2002-2003 10 0.477 0.040 0.55
Lafarge Seattle Type I-II 2002-2004 6 0.440 0.59
Lafarge Richmond BC Type III 2002-2004 6 0.432 0.038 0.50
CaO alkalis Available Alkalis
TYPE # Std 95% Std 95% Std 95%
PRODUCER LOCATION ASH YEAR TESTS Avg Dev level Avg Dev level Avg Dev level
ISG CENTRALIA F 2001 69 8.80 0.84 10.48 3.68 1.00 5.68 1.00 0.31 1.62
2002 101 8.43 0.56 9.55 3.13 0.75 4.63 0.78 0.23 1.24
2003 114 7.96 0.68 9.32 3.07 0.57 4.21 0.20 0.08 0.36
2004 34 8.91 0.60 10.21 4.09 0.45 4.99 1.27 0.25 1.77
ISG BRIDGER F 2002 153 7.48 1.05 9.58 4.29 0.46 5.21 1.20 0.30 1.80
2003 146 7.48 0.83 9.14 3.82 0.43 4.29 1.62 0.24 2.10
2004 36 8.05 0.38 8.81 4.34 0.31 4.96 1.90 0.15 2.20
100b Study Of Materials History Of Aggregates
Aggregate Geology and Standards
Based on discussion on April 20,2004 with Steve Lowell: Equating Puget Sound Aggregate
deposit to Canadian deposits in coastal British Columbia is a great over simplification of the
circumstances. True, much of the rock material was transported by the continental (Cordilleran)
glaciations. There are many other contributions and processes that had their own contribution to
the deposition we now experience. In the process of glacial advance and retreat, mixing and
reprocessing occurred which combined the effects of and contributions from Cascade Range
drainages, virtually all of which have igneous elements in their origin. Igneous (volcanic)
sources inherently have the possibility of including the minerals characteristically considered as
potential sources of reactive silica.
Aggregate sources in the remainder of the State, while having little or nothing in common with
coastal British Columbia in their origin and deposition cannot, by virtue of their origin, be ruled
out as to potential reactivity. Glacial flood phenomena and the erosion of the channeled
scablands included transported and eroded components that are potentially reactive. Drainages
from the Eastern slopes of the cascades tap into the same igneous origin materials considered
capable of generating quantities of reactive siliceous materials. Some limited areas were not
subject to this erosion process (possibly the Pend Oreille- Ferry-Stevens county vicinity and the
Blue Mountains in extreme Southeast Washington). These areas are metamorphic in nature,
which may also contribute reactive components
Considering the Southwestern quadrant of the state, this area is actually a combination of the
Columbia River deposition with Cascade origin thru drainages such as the Cowlitz and Lewis
rivers. Both of these rivers were directly influenced by glaciations and deposition from igneous
origin materials and the further contribution of Bretz Flood outwash, down the Columbia and
through the Wallula gap and into the Portland vicinity.
It should not be assumed that because of the absence of extensive occurrence of ASR
determination that no reactive aggregates exist. Neither can it be assessed that, since there are
potential sources of reactive matter, that all sources are likely suspect. Each source and site has
elements that influence its individual character. The only sure course for determination is to
check out each potential aggregate producing site. While quarry sites may be somewhat more
homogenous in origin than gravel deposits, flow characteristics may contribute to within-site
variability. This would apply chiefly to coarse aggregate since customarily no fine concrete
aggregate is produced from a quarry source.
Aggregate Source Qualification
Existing records were compiled for currently evaluated concrete aggregate sources. Records
were examined for qualification activities since 1998. WSDOT standards require
prequalification of aggregates sources for concrete aggregate on a interval of five years so the
time period involved should cover all the generally active sites. The database involved contains
evaluations of 145 sites. Of these 145, 10 sites were qualified based on ASTM C 1260 testing, 9
were qualified for concrete aggregate use based on ASTM C 1293 (one year) test results and an
additional 13 sources were qualified based on ASTM C 295 Petrographic Analysis of Aggregate.
This totals 32 sites, which are acceptable for concrete aggregate usage without submission of
proposed mitigation measures. Considering that there might be significance in the relative level
of reactivity, as indicated by the ASTM C 1260 expansion measurements, the results were
broken down into several groups.
• 9 sites had results below 0.10% expansion,
• 32 had expansion values greater than 0.10 but less than 0.21% (3 of this group were
qualified based on ASTM C 295).
• 41 sites had expansion values greater than 0.20 but less than 0.31 (9 were accepted, 8
based on ASTM C 295, 1 based on ASTM C 1293).
• 27 sources noted expansion results between 0.30 and 0.41, (One of these was accepted
based on ASTM C 1293 results, one on Petrographic Analysis (ASTM C 295)
• A final group of 28 sites had expansion results greater than 0.40, up to 0.75, In this group
5 sites were qualified, without mitigation, 1 by ASTM C 1293, 3 by ASTM C 295
Petrographic analysis and one by both Petrographic Analysis and ASTM C1293.
Considering the results only from ASTM C 1260 (AASHTO T 303) at 14 days the variation of
expansion results of by groups was:
• 0.10% or less: 10 sites
• Over 0.11 and 0.20% or less: 33 sites
• Over 0.20 and 0.30% or less: 41sites
• Over 0.30. And 0.40% or less: 28 sites
• Over 0.40 and 0.50% or less: 11sites
• Over 0.50% 17 sites
As a part of this study the Geographic Information System prepared an initial map presenting the
location of tested sources. This map used color code superimposed on the symbols indicating the
level of reactivity per ASTM C 1260 and C 1293. Sites were grouped in increments of
increasing expansion test results similar to those discussed above. In large format the map
provided a picture of general trends and distribution of reactive (expansive) materials. It is
available for inspection in the Materials Laboratory and was the impetus to preparation of a
simplified, more general graphic.
A map was prepared using a three-level grouping of results, based on AMBT (ASTM C-1260).
This map is included on the following page (Figure 1: Relative Reactivity of Aggregate Sources
The three levels utilized were: Low, ASTM C-1260 expansion results 0.20% or less, Moderate,
ASTM C-1260 expansion results 0.45 % or less but greater than 0.20% and High, ASTM C-
1260 expansion greater than 0.45%. It is pertinent to recognize that these are not absolute
categories of reactivity. This map does not identify the final determination of suitability for
concrete aggregate under current WSDOT Standards.
These categories were based on a consideration of possible future action levels. The upper limit
of 0.20% was based on discussion papers as contained in the 11th ICAR conference. The 0.45%
limit appeared as an intuitive separation point of the remaining sources.
FIGURE 1 MAP: RELATIVE REACTIVITY OF AGGREGATE SOURCES
Evaluation of present aggregate test findings
The examination of aggregate source characteristics is based on ASTM C 1260, the Accelerated
Mortar Bar Test Results. In ascribing relative degrees of reactivity to these results it should be
borne in mind that ASTM C 1260 is an index of potential reactivity with ultimate reactivity only
definitively assessed by the longer test, ASTM C 1293. Examining aggregate reactivity test
across the state, there is a general pattern of greater reactivity in the lower Columbia basin.
However, in general reactivity is not absent from any locality. There are also some noted
performance deficiencies, which have a possible correlation to this level of reactivity. Clustered
near Prescott and to the North of Pateros are several structures displaying similar degrees of
deterioration. Some structures are so old that source data is unavailable. Further implications of
this correlation is the higher levels of reactivity noted for Oregon sources. Hypothesis is that this
relates to the mineralogy of the sand and gravel produced by erosion of the Columbia plateau
basalts thru the channeled scablands and coulee formation. This would agree with the carrying
of this material downstream in the Columbia and its distribution and deposition in the aggregate
gravel bars down the drainage.
Review of test results and test methods
The information on file in WSDOT’s Aggregate source files indicate that the general tendency is
for a source initially classified as reactive (actually requiring mitigation, under Standard
Specification Section 9-03.1), to be determined as not requiring mitigation when further
evaluated either by Petrographic Analysis (ASTM C-295) or by one year testing (ASTM C1293).
The initial evaluations are based on aggregate material provided by the contractor, generally with
WSDOT involvement and tested by ASTM C 1260 in WSDOT facilities. Subsequent
information in WSDOT’s file (i.e. petrographic analysis and C 1293 results) is that received from
the contractor/supplier. There is no requirement that the contractor/supplier submit all test
results. It is possible that this may lead to submission of only positive information. There may
be adverse information that is not in WSDOT files.
Within the available information there is a contradiction of other investigators findings when
comparing the data from Test Methods C 1260 and C 1293. Thomas and Innes, in a study
reported in Cement, Concrete and Aggregates Vol 21 No 2 Dec 1999, generally showed
agreement as to potential reactivity comparing these two methods on identical aggregate
samples. That is, an aggregate found to be potentially reactive (expansion at 14 days exceeding
0.10 %) exhibited deleterious expansion (exceeding 0.04%) when subject to testing under C-
1293. WSDOT’s information contradicts this, based on the information on file. That is that
sources found to be potentially reactive under ASTM C1260 were determined to be non-reactive
when tested under ASTM C 1293. There is no evidence that the actual materials were identical
as parts of split samples nor is there verification as to the identity of the tested material since
these submissions for ASTM C-1293 were under the control of the supplier.
The referenced study involved comparison of a number of aggregate combinations and proposed
mitigative measures. An additional generalized result was that 25% class F fly ash was generally
effective in mitigating expansive reactions.
Interpretation of WSDOT Specifications
The use of Petrographic analysis (ASTM C 295) results to provide aggregate approval for
material failing ASTM C 1260 seems to be a contradiction to the intent of the ASTM aggregate
specifications. As a matter of interpretation, it also seems to go against the intent of the
foundation AASHTO guide specification as well. The guide specification is that of the current
AASHTO Guide Specifications, “Section 56x Portland Cement Concrete Resistant to Excessive
Expansion caused by Alkali Silica Reaction” and was obtained from the AASHTO Innovative
Technologies website. Taken in context for the collection of ASTM standards starting with
ASTM C33 (Concrete Aggregates) the recommendation for consideration of aggregate reactivity
is to first consider the history of production and performance for an existing source. Lacking
performance records as to reactivity, the next investigation is ASTM C 295 Petrography. Where
potential reactive minerals are found (ASTM does not define quantitative limits) ASTM
recommends further investigation by testing utilizing C 1260 & C 1293, with C 1293 being the
most definitive determination.
The AASHTO guide specification seems to propose a similar sequence. It provides numerical
values for potential reactive materials in connection with Petrographic analysis. Exceeding these
values implies definite reactivity. Aggregates testing below these limits are not explicitly defined
as excluded from consideration of reactivity. In the opinion of this investigator, consistency with
AASHTO practice would be for any aggregate found to have potential reactive components
present to be evaluated by T 303 (ASTM C 1260) and definitively by ASTM C 1293 (no
AASHTO counterpart). WSDOT’s use of these factors (the limiting values for reactive
components) seems to be contrary to the specification’s intent.
WSDOT specifications allow the use of aggregate with identified potential ASR when the
supplier submits mitigation measures. This submission is to the WSDOT Region’s Project
Engineer and further review or even submission for record is not required. Accordingly of the
113 sites, which would require mitigation of potential ASR, the central database does not reveal
which sites and what mitigation was submitted.
Aggregate analysis reports were obtained for several existing concrete aggregate sources.
Construction Technology Laboratories (CTL) prepared these reports. Where reporting is
independent of confirmation to WSDOT standards, these reports indicate that practice is to use
petrographic results to identify potentially deleterious components, and then to recommend
confirmation testing by ASTMC 1260 or C 1293 wherever potentially reactive materials are
Additional copies of test reports for ASTM C 295 (Petrographic Analysis) and C 1293 (Concrete
Prism test) were obtained from WSDOT files for review. These reports had been prepared
under the provisions of Standard Specification 9-03.1. That standard requires that the
performance and submission of these results is the obligation of the Contractor whenever it is
found that ASTM C 1260 (T 303) results exceed the limit of 0.10% expansion. The selection of
testing laboratory, provision of samples, and return of test information is under the
contractor/supplier’s control. As a consequence there is significant variation in the wording and
detail provided in the reports.
Four different laboratories were used for performing ASTM C 1293 on ten different sources.
None of the testing laboratories had any role in obtaining the aggregate samples. From the
reported information it appears that in some cases a third party was involved in the transmission
(i.e. a contractor furnished to a cement company representative who forwarded to the lab). There
is also no indication in the files that any samples were evaluated using ASTM C 1293 and were
found unacceptable. ASTM C 1293 further has specific requirements concerning the alkali level
of the Portland Cement utilized in the test. With one exception, in the reports on file, the alkali
level, source and additional alkalis furnished to prepare the samples is addressed only in general
terms as “test conducted in accordance with ASTM C 1293” The one exception, in fact
documents a deviation from ASTM C 1293. This particular report, from Northwest
Laboratories, reported on three sources B 333, B 345 and B 329, indicates that a common type
I/II cement with alkali content of 0.48% (ASTM C 1293 requires not less than 0.90%) was used
with additional alkali added in the mixing water. This laboratory did document that the alkali
level was at the appropriate 1.25% however their approach departs from the standard set by C
In general the reports on file do not conform to the ASTM requirements for detailed reporting of
sample preparation, materials utilized and individual test readings during the course of the test.
In comparing the reports provided with those referenced in the data base one source, G 106
apparently has no test results on file, and one source, B 329, has acceptable results in the file
which do not show up in the data base.
14 aggregate sources were listed in the database with acceptance based on ASTM C 295. Two
different laboratories were utilized for these reports. In responding to the client’s request the
laboratories comment that they are responding to the WSDOT specification requirements for
content of potential reactive minerals. In reporting their results, the originating laboratories note
the presence of reactive materials in the samples and state that their determination is based on
conformance to the published standards of WSDOT for chemical composition rather than
commenting on the implication of reactive materials identified. The documentation and detail of
these reports is extensive. The reporting laboratories identify that their analysis is based on
samples received from parties connected to the physical source and there is no evident
involvement by the reporting laboratory in obtaining the materials. Nor is there any evidence that
WSDOT had any role in the sampling process. One source included as approved in the database,
site C 290, and is documented to fail the petrographic analysis. The reporting laboratory notes
this and recommends additional testing. Two other sources OR 27 and G 106 are of interest since
they are in Portland/Vancouver area. Both have volcanic glass contents near the specification
limit and demonstrated high potential reactivity when tested by ASTM C 1260. Site G 106 had
additional testing and was found satisfactory under ASTM C 1293. No supplementary tests were
run on OR 27.
In working with the WSDOT aggregate source database, a number of possibly clerical
discrepancies were found. These are of undetermined origin but may indicate a need for further
investigation. Most appeared to be clerical errors such as a confusion between legal and physical
description. (A site designated by suffix as being in one county has a legal description that places
it outside that counties boundary) Others noted information inconsistent with other
circumstances of the source, such as a source in southwestern Washington noted as being
operated by the Colville Confederated Tribes (highly unlikely). Considering that the database is
voluminous and that only currently accepted concrete aggregate sources were accessed, the
amount of errors might warrant a thorough review of the information at hand. It is understood
that the ASA database has been compiled by a number of operators over a span of time and very
possibly reflects inadvertent copying of non-critical fields from one record to another. Errors at
any point in a system deteriorate the confidence in the integrity of the entire system.
Survey of WSDOT practice
A brief survey was compiled to evaluate the practices currently used by WSDOT project offices.
The survey questions and summaries are provided on the following page. This inclusion is
verbatim from the survey and response and does contain some typographic errors.
Of the 45 offices contacted, 18 responded. These responses came from South Central,
Southwest, Olympic and Northwest region.
Of the 18 responders, 15 had current experience with accepting cement concrete mix designs.
Observations from the responses are:
For one project the contractor did not submit a mix design proposal.
Of the remaining 14, 7 required mitigation based on the submitted source.
Six of the 7 used fly ash addition,
One used Slag Modified cement.
About half of the offices responded that the mitigation measures had been forwarded; the balance
retained them at the project records.
No offices reported the use of low-alkali cement as a mitigation measure.
The responses seemed somewhat mixed as to the process and the intent involved. The
information reported seems somewhat ambiguous. . For example, the possible interpretation that
low-alkali cement could be approved by itself does not seem to have occurred, to the offices
reporting. Considering the language of the specification and the apparent absence of established
process and guidelines this is understandable. Furthermore there seems to be no ready reference
to the submitted mitigation procedure or to the process for approval of concrete mix designs.
Absent any changes in specifications and practices, there seems to be a need for clearer
guidance. Considering that there may be revisions to the standards as a result of the current
study, the Agency should consider an aggressive training and guidance program with respect to
concrete mix design review and approval of mitigation measures.
Required mitigation was introduced in the 2000 specifications and revised to its present form in
the 2002 edition. It is not clear what guidelines or process is established for obtaining the
mitigation information or what criteria may be furnished to the contractor for this process.
Project offices report that mitigation measures have been submitted to the Lab but none seem to
be on file. Disposition of these reports is unknown at this point.
ASR MITIGATION SURVEY: QUESTIONS
ASR MITIGATION SURVEY RESPONSES
Combined Investigation Subtasks
In the preparation of the original study plan subtasks were defined for the perceived necessary
phases to achieve the desired results. In practice, for the activities separate from the study of
standards and materials, these activities were conducted jointly. It is more meaningful to discuss
this group in combination. The elements which were combined were those listed in the
introduction and the study agreement as:
Subtask 100c Investigate And Obtain Project Data
• Task 200 Review Recent Pavement Or Structure Construction, with subtasks:
200a Identify Candidate Projects For Field Examination
200b Develop Summary Of Construction Data
Selection of prospective investigation structures and pavements
WSDOT had prepared a study list and guidelines at the inception of ASR concerns, in 1999. At
that time, in the process, the Bridge Condition Information database was examined to identify
defect listings consistent with possible ASR occurrence. The selection process then narrowed
those down to a final list of twenty-one sites. This “1999 List” was used for a starting point.
Contacts were made with other bridge resources and field personnel. In addition a further query
was made of current listings in the Condition Survey, Parameters were expanded from those used
in the 1999 query, expanding query terms to include “map cracking” and “leachate”.
Requests were also initiated for the Pavement Condition rating, looking for sections possibly
exhibiting characteristic ASR defects. In particular examination was made of the oldest PCC
pavements. No significant deterioration of any nature was noted in these reports. Personal
contacts were pursued as to any section possibly worthy of inclusion in the study and none were
disclosed. Concurrent with this study, however, a section of pavement near Bellingham was
identified for further evaluation.
Results of extension of the original structures list were mixed. Several possible investigation
candidates were identified through personal contacts. Re-examination of the “1999 List”
identified additional potentials. The extended search of current bridge condition information
resulted in a greatly expanded list, partially resulting from the extended defects listed. This
provided a massive list of a size difficult to manage as a selection tool. Unfortunately, due to
untimely death of a key staff member of the Survey section it was not possible to do further
refinement of this screening effort. The extensive list did provide current information on those
sites ultimately selected for follow up. Personal contacts also expanded information on sites not
on the WSDOT system and identified structures no longer in service that had exhibited early
deterioration attributed to ASR.
Collection of Individual Structure Information
WSDOT’s Bridge information system has complete historical information for each site currently
on the system. The records are complete as to physical location and structure and establish the
original construction date and contract. This enabled the extension to materials records through
the testing records in the Materials laboratory. The data information was traceable back to test
records of structural concrete cylinders, even back to construction in the 1930’s. The records
reveal information collected at the time of construction and through their completion by the
Agency staff on the site, should reflect accurately the material being employed in the
construction. There are some anomalies in that the records do not exactly match with information
in current sources records and in some cases reflect terminology not exactly traceable to current
Where prospective structures are not on the WSDOT system, this same system of traceability did
not function well. Particularly for structures constructed early, notably Mannette Bridge, and
other structures not constructed on WSDOT contracts no information is available based on
contacts with the responsible parties (FHWA/NPS)
Selection of candidate sites/segments
A list of candidate projects and structures was developed for consideration. It was recognized
that some redundant opportunities existed in this list. Some selection was made based on the
likelihood of reaction being present based on the documented origin of aggregate. Particularly
with respect to the aggregates from the Spokane area that have established a low probability of
reactivity, some candidate structures were eliminated from the list. Also, with respect to
structures in the Methow region, one structure was selected as representative of a number of
bridges constructed under the same contract and time frame.
This candidate list was used as the basis for a field review. To better determine the needed
organization for the actual field work, a field reconnaissance trip was made. This trip served to
further screen and select sites as well as consider the actual collection effort based on traffic level
and site geometry. The list of structures considered prior to the field tour is contained in Table 3
“ASR STUDY CANDIDATES on the following pages.
Table 3CANDIDATE SITES
Bridge # Bridge Name I.D. Year Age SR/M.P. Region Nearest Town Defect/Location
1 12/620 NINE MILE CR UP RR OC 0001724B 1933 71 12/314.16 SC WALLA WALLA BR; DECK: Map cracking
2 12/640 SR 125 OC 0009110A 1972 32 12/335.9 SC WALLA WALLA BR; Map cracking
3 12/643 9TH AVE OC 0009110C 1972 32 12/336.15 SC WALLA WALLA BR; Map cracking
4 26/253 UP RR OC 0008153A 1967 37 26/102.76 EA HOOPER Map cracking, deck & Columns
5 90/531S ABBOT RD OC 0006857C 1962 42 90/277.51 EA SPOKANE Map cracking bottom, of deck
Bottom slab cracking, leaching,Map
6 90/540S HANGMAN CR 0006579A 1963 41 90/279.49 EA SPOKANE cracking in columns
AHTANUM CR: RR & RAMP Map cracking in deck,CBR: Surface
7 97/140E OC 0011580A 1981 23 97/75.92 SC YAKIMA Map Cracking
8 97/145E I-82 OC, NBL 0011580C 1981 23 97/76.31 SC YAKIMA NJB: Hairline map cracking
Soffit many leackhing cracks,
9 99/540SB ALASKA WAY V SB 0003935B 1957 47 99/29.84 NW SEATTLE stalctites
CBR: Baluster Rails exfoliated &
10 101/266 DUCKABUSH RIVER 0001764B 1934 70 101/310.22 OL HOODSPORT spalled
Deck is ASR candidate, Map cracking
11 124/14 COUNTY RD OC 0006854A 1962 42 124/27.48 SC PRESCOTT in deck, wingwalls, abutment
12 125/23 DRY CREEK 000000GX 1921 83 125/12.30 SC PRESCOTT CBR Map cracking throughout
13 125/28 SPRING VALLEY BRANCH 0000000GY 1921 83 125/15.49 SC PRESCOTT CBR: Baluster Rails exfoliated & spalled
14 125/35 TOUCHET RIVER 0000000FZ 1916 88 125/23.38 SC PRESCOTT CBR: Baluster Rails exfoliated & spalled
SOFFIT: LEACHING & CRACKS,
15 153/3 METHOW RIVER 0001658A 1933 71 153/3.66 NC PATEROS Baluster rails cracked & exfoliated
153/10 et. same as 153/3 above, multiple
16 Al. METHOW RIVER 0002450A 1939 65 153/11.83 NC PATEROS structures on this same contract
17 153/16 METHOW RIVER 0003507A 1939 65 153/16.85 NC PATEROS same as 153/3 above
SO FK TOUTLE-COAL
18 504/10 BANKS 0012129A 1982 22 504/11.04 SW CASTLE ROCK CBR:Extensive Map Cracking
Table 3 - CANDIDATE SITES
Bridge YEAR Bridge CONST. AGGREGATE
Number Bridge Name Structure I.D. CONST. Age SR/M.P. CONTRACT SOURCE CEMENT SOURCE
1 12/620 NINE MILE CR UP RR OC 0001724B 1933 71 12/314.16 1724 Edgar Brown Lehigh , Spokane
2 12/640 SR 125 OC 0009110A 1972 32 12/335.9 9110 ORE-30 , FN-50 ORE PORT LIME Type 2
3 12/643 9TH AVE OC 0009110C 1972 32 12/336.15 9110
4 26/253 UP RR OC 0008153A 1967 37 26/102.76 8153 C-117 Lehigh Type 2
5 90/531S ABBOT RD OC 0006857C 1962 42 90/277.51 6857 Could not find Could not find
6 90/540S HANGMAN CR 0006579A 1963 41 90/279.49 6579 C-4 Lehigh type 2
7 97/140E AHTANUM CR: RR&RAMP OC 0011580A 1981 23 97/75.92 1580 E-14- Ideal Type 2
8 97/145E I-82 OC, NBL 0011580C 1981 23 97/76.31 1580 E-14- Ideal Type 2
9 99/540SB ALASKA WAY V SB 0003935B 1957 47 99/29.84 3935 Steilacoom Permanente Type 2
10 101/266 DUCKABUSH RIVER 0001764B 1934 70 101/310.22 1764 Duckabush Riv. Hyurly
11 124/14 COUNTY RD OC 0006854A 1962 42 124/27.48 6854 Jones/Scott Ideal type 2
12 125/23 DRY CREEK 000000GX 1921 83 125/12.30 unk
13 125/28 SPRING VALLEY BRANCH 0000000GY 1921 83 125/15.49 unk
14 125/35 TOUCHET RIVER 0000000FZ 1916 88 125/23.38 unk
15 153/3 METHOW RIVER 0001658A 1933 71 153/3.66 1658 Cntr Pit Northwestern
16 153/10 et. Al. METHOW RIVER 0002450A 1939 65 153/11.83 2450 U-80 Northwestern
17 153/16 METHOW RIVER 0003507A 1939 65 153/16.85 3507 no record no record
18 504/10 SO FK TOUTLE-COAL BANKS 0012129A 1982 22 504/11.04 2129 L 119 L.S Type 2
Task 300 PREPARE STUDY PLAN: ASR FIELD TESTING PROGRAM
The structures identified for testing are those that exhibit a degree of deterioration beyond the
normal expectation. In some cases (i.e. map cracking of bridge railing) the degree of
development is consistent with early onset of ASR but could also result from other causes
including construction placement and curing practices. The field-testing effort was intended to
primarily determine whether ASR is in active progress and, secondarily, if ASR is not present,
document the condition of the concrete as to the possible explanation for the noted performance.
For example map cracking of concrete can result from drying exposure while freshly placed,
from freeze-thaw cycling as well as from ASR. Water addition, during placement or finishing,
can create localized sections of high water/cement ratio concrete with reduced strength and
The candidate list of bridges was developed from record searches and anecdotal information as
those most likely to display ASR type defects. It would not be expected that ASR deterioration,
if present, would occur uniformly throughout the structure. The first component of fieldwork at
each site would be to locate the prospective testing area using the condition reports combined
with on site inspection. It would be more likely to develop where conditions have resulted in
saturation of the concrete. This may require balancing access efforts against optimum test site
location however it is important to recognize that ASR development would not be expected to
uniformly occur in all parts of the structure.
Individual field tests and sampling procedures
The following program was prepared to identify the expected typical tests and sampling
Selection of testing/ sampling location considering saturation and drainage factors
Preparation of sites for ASR detect test
ASR detect test
Collection of powdered residue
Core sampling of test sites
Photo record of before and after locations
Written record of sampling/testing activities
Subsequent tests and evaluations
Anticipated testing will involve WSDOT materials facilities and staff except for core sample
analysis which will be performed by outside laboratories: Concrete Technology Laboratory
(CTL) or equivalent.
Expected submissions and evaluations would be:
Documentation of structure condition and sampling location
Documentation of concrete conditions during sampling: hardness, rebar condition
Documentation of ASR detect results, verbal & photographic
Core sample analysis
Linear traverse for entrained air structure
Petrographic analysis for ASR
Petrographic analysis for aggregate mineral composition
Powdered sample analysis
Cement content determination
Alkali content determination
Comments on individual sampling/test procedures
At the outset it was acknowledged that an exception would occur with respect to bridge 5/537S.
Knowledge of this structure indicates that bulk samples of the bottom soffit can be removed
mechanically. Bulk samples will be obtained on site and returned for testing and evaluation in
Field-testing and sampling is not an end in itself but a means to gather materials and information
for evaluation. Other procedures that accomplish these same goals should be satisfactory. In
executing the field work, WSDOT determined that obtaining multiple cores for tests and
evaluations in the laboratory was more effective and efficient than preparing multiple sites for
LANL (ASR Detect) field tests.
Comments on powdered sample analysis.
It was considered that, utilizing the chloride sampling capabilities of the regions or further
processing of materials recovered from the test sites, determinations could be made of the
estimated cement content and of the cement alkalis content of the tested structures. As a control
measure a sample of known composition would be subject to the same test methods. From this
information it should be possible to compare the properties of the concrete sampled with what
would have been expected for nominal concrete designs of the same construction time frame
It is recognized that variations may have occurred in the past. Some localized or unidentified
cement of higher alkali content may have made their way into the product. Some variation and
increases for job conditions, particularly concern with attaining early strength may have raised
cement contents above the design level. Investigation of this aspect was predicated on the
analytical capability of the resultant material. Chief Chemist Jeanne Andreasson reviewed the
required procedures and possible accuracy of likely results. Based on available staff and
equipment, her recommendation was that this aspect of the investigation should not be pursued.
Anticipated equipment and support requirements
Access provisions dependent on structure location (UBIT, Lift Truck, Ladders, Scaffolds)
Traffic control measures (Daylight operation desirable)
Power source (generator)
Concrete preparation (Grinder, Bush hammer)
Sample collection (vacuum drill Chloride testing)
Concrete core drill and barrels w/ associated cooling medium (water, gas)
Site restoration: quick set concrete patching along with support/curing as required.
Regional contact would be initiated through Regional Materials
Regional materials involvement was considered as optional but not required
ASR Field Testing
Based on the preliminary preparations field studies began in August 2004, initiated with sites
closest to the Tumwater Laboratory. After initial trips to the nearest locations, a reconnaissance
tour was made of possible eastern Washington locations. From the results of this trip, the site list
was revised. Some sites, such as 5 thru 9 in Table 3 were removed from the list based on site
examination. Sites 12, 13 & 14. were deleted due to their great age. Sites were added to better
select possible defective concrete. These would be the Touchet River Bridge on SR 12 and the
Foster Creek Bridge on SR 17 and an additional concern was expressed as to pavement
performance on SR 5 near Bellingham.
These selected sites are summarized in Table 4 entitled “Site Descriptions” and Table 5
“Materials Data” on the following pages. A location map is also included (Figure 2) The “Site
Descriptions” table includes data on four ‘reference’ bridges that were not a part of the field
investigations. These are structures that have been identified as ASR occurrences either by
formal test or anecdotally
The site identified as #12, Mannette Bridge was identified as ASR through WSDOT coring and
testing previously. While it is in a marine, tidal environment, it has been determined that the
erosion and deterioration of supporting columns is at least partially attributed to ASR.
The three structures in the Cayuse pass vicinity 13 A, 13B, & 13C have a common origin in
construction under Federal Authority (Bureau of Public Road)) pre WW II. Based on discussion
with personnel involved with their demolition and reconstruction, the physical appearance and
degree of deterioration was totally compatible with assigning ASR as the cause of their early
demise (All were replaced due to deteriorated condition at about 50 years service) These
structures, are in proximity to the NPS studies sites. A common element of this era of
construction would have been utilization of gravel sites in the near proximity rather than
transportation from remote sources. This vicinity is in very close association with igneous flow
origins associated with Mount Rainier.
Site Conditions conducive to reaction
Observing deterioration on existing structures, it was noted that thinner sections, particularly
bridge rails show more deterioration than other portions. These sections are generally thinner
than the major structural members. They are also much more exposed to the sun particularly the
upper surfaces and segments. Given equal exposure to the sun, these thinner elements would be
relatively warmer. Particularly structural members, deck and girders are shaded and usually sun
exposed only on one side. The reaction associated with deterioration is generally considered to
be endothermic, that is driven by external heating, rather than exothermic, generating excess heat
as a product of reaction. Consider that the basis for C 1260 is achieving early results through
running at an increased temperature. For any set of given conditions, then, those sections with
greater exposure to solar energy would have more advanced deterioration due to external energy
available to drive the reaction.
TABLE 4 TESTAND REFERENCE SITES:
Bridge Structure YEAR Bridge
Number Bridge Name I.D. CONST. Age SR/M.P. Region Nearest Town Defect/Location
SOFFIT: LEACHING & CRACKS,
1 5/537S EB LANES I-5 O-C 0007741T 1966 38 5/163 NW SEATTLE exfoliated
HOODSPORT CBR: Baluster Rails exfoliated &
2 101/266 DUCKABUSH RIVER 0001764B 1934 70 101/310.22 OL (21 Mi. S) Spalled
SO FK TOUTLE-COAL CASTLE ROCK
3 504/10 BANKS 0012129A 1982 22 504/11.04 SW (11 mi. W) CBR:Extensive Map Cracking
Deck is ASR candidate, Map
PRESCOTT cracking in deck, wing walls,
4 124/14 COUNTY RD OC 0006854A 1962 42 124/27.48 SC (7 mi. E) abutment
WALLA WALLA CBR: Baluster Rails exfoliated &
5 12/624 TOUCHET RIVER 0002241A 1936 68 12/319.35 SC (17 Mi. E) Spalled
PATEROS(12 SOFFIT: LEACHING & CRACKS,
6 153/10 et. Al. METHOW RIVER 0002450A 1939 65 153/11.83 NC mi. S) Baluster rails cracked & exfoliated
DUSTY (14 mi.
7 26/253 UP RR OC 0008153A 1967 37 26/102.76 EA E) Map cracking, deck & Columns
Hairline cracking with some
8 17/306 EAST FOSTER CK 0003759A 1950 54 17/127.23 NC LEAHY (7 mi. E) leaching
9 OHANAPECOSH CG NPS 1960 44 (~14 mi. W) Minimal Distress
STEVENS CANYON PACKWOOD
10 ENTRANCE NPS 1956 48 (~14 mi. W) Leaching, exudate
Panel cracking, delamination
11 5/Pavement SR 5 SOUTHBOUND n/a 1961 43 5/254.60 NW BELLINGHAM lower portion
12 303/4a MANETTE BRIDGE 0003531A 1930 74 303/1.47 OL BREMERTON Reference: ASR Identified
ENUMCLAW (38 Replaced due to ASR type
13A 410/70 DEADWOOD CK 8611400 1939/1994 410/62.94 NW mi. W) deterioration
PACKWOOD Replaced due to ASR type
13B 123/5 LAUGHINGWATER CK 8611500 1935/1994 123/4.94 SW (~15 mi. W) deterioration
PACKWOOD (10 Replaced due to ASR type
13C 12/284 CORTWRIGHT CK 0012115A 1934/1984 12/140.31 SW MI W) deterioration
TABLE 5 TEST SITES: MATERIALS DATA
Bridge YEAR Bridge CONST. AGGREGATE
SITE Number Bridge Name Structure I.D. CONST. Age SR/M.P. CONTRACT SOURCE CEMENT SOURCE
1 5/537S EB LANES 1-5 O-C 0007741T 1966 38 5/163 7741 B-58, B-1 Permanente Type 2
2 101/266 DUCKABUSH RIVER 0001764B 1934 70 101/310.22 1764 Duckabush Riv. Hyurly(sic)
3 504/10 SO FK TOUTLE-COAL BANKS 0012129A 1982 22 504/11.04 2129 L 119 L.S Type 2
4 124/14 COUNTY RD OC 0006854A 1962 42 124/27.48 6854 Jones/Scott Ideal Type 2
5 12/624 TOUCHET RIVER 0002241A 1936 68 12/319.35 2241 Jones/Scott Lehigh HES
6 Al. METHOW RIVER 0002450A 1939 65 153/11.83 2450 U-80 Northwestern
7 26/253 UP RR OC 0008153A 1967 37 26/102.76 8153 C-117 Lehigh type 2
8 17/306 EAST FOSTER CREEK 0003759A 1950 54 17/127.23 3759 DO -73 Northwest II
9 CCAMPRGOUND NPS 1960 44 NPS/FHWA
10 STEVENS CANYON ENTRANCE NPS 1956 48 NPS/FHWA
11 5/Pavement SR 5 SOUTHBOUND N/A 1961 43 5/254.60 6249
FIGURE 2 TEST SITE LOCATIONS
TASK 400 PREPARE FINAL REPORT
Subtask 400a Documentation of test results
Field Test Results
A summary of the field investigations and test results has been prepared for each of the eleven
investigated projects. These individual site summaries are presented on the following pages. The
index map to test site locations and tabulated information on each site was presented in the
preceding section. The individual site summaries extract the pertinent information and test
results for each site. Full information including site and sample photographs and fully
documented reports of the core sample testing is contained in a separate binder prepared and
maintained at the Materials Laboratory.
An extract from the photographic record has been prepared and is included following the listing
for individual test sites. This record is presented to provide visual examples of the types of
defects noted. The comments for each example indicate whether ASR deterioration was
responsible. AS has been noted in the research material on this subject, it is not possible to
define the cause of deterioration solely form the physical appearance. Further testing and
i9nvestigations are necessary to definitively identify ASR occurrence.
Site number and description: SITE #1 EB LANES I-5 OVER CROSSING
Location: (NW Region, SR5 MP 163 South Seattle at Spokane Street connections
Climate & Weather: Puget Sound Climate, Rain, moderate to mild
Condition Report: Bridge soffit leaching, cracking, concrete in punky condition.
Structure was constructed in 1966 as a portion of Contract 7741, 38 years old at time of sampling
Materials sources/comments: Aggregate from B-58, B-1 (Steilacoom) Cement: Permanente Type
2 equates to Kaiser, plant not known
August 2,2004, Jeff Donaldson & Bridge Office Crew used hydraulic work platform
Sample types Block sample removed from NE corner span 11 with rock hammers
Field observations: Concrete appeared punky with a powdery consistency. Taken from an
area of leachate
WSDOT tests/evaluations: ASR detect test at Laboratory, No reaction with Yellow stain,
concluded no ASR present
Routing to Laboratory: Received by CTL November 11, 2004. Reported results on February 4,
2005 as CTL Project No. 153962.
CTL Laboratory results
The laboratory reported this sample as from “The Spokane Street Bridge in Spokane,
Washington. The structure sampled is a connection to the Spokane street structure, also known
as the West Seattle Freeway, which is in fact in Seattle. The samples were taken from a structure
on the WSDOT system as a part of SR5
ASR: ”No evidence of deleterious alkali-aggregate reactions (such as ASR).”
Aggregate comments: “some rock types that are potentially reactive…”
Deterioration noted: ”concrete of poor condition and poor quality. Extensively cracked
and microcracked throughout… carbonation extends fully throughout the sample… exhibits
evidence of poor consolidation, poor mixing, and segregation of aggregate and cement
binder….,concrete is not air entrained and therefore not properly protected from frost-related
damage” “water-cement judged moderately high to high.”
Air Structure: The concrete is not air entrained and air content is estimated at about 1%.
The comments relative to concrete condition indicate likely poor handling during the
construction mixing/placement process. It would have been expected that this concrete would
have been air-entrained.
Site number and description SITE #2 DUCKABUSH RIVER BRIDGE
Location: Olympic Region, SR101/MP 310.22, 21 miles north of Hoodsport
Climate & Weather: Olympic peninsula, Rainy moderate to mild
Condition Report: Concrete Bridge Rails Baluster rails exfoliated and spalled
Constructed 1934 under Contract 1764, 70 years old
Materials sources/comments: Aggregates source shown as “Duckabush River” No comparable
current sources Cement: Hyurly(sic) no other source information.
Date August 17, 2004 Don Brouillard, Jeff Donaldson & Materials Lab crew, Olympic
Region traffic control
Sample types two 4-inch cores taken from rail. Coring performed on overflow structure
0.1 mile north of Duckabush River. Performance same, constructed on same contract, based on
structure identification. Number.
Field observations: Concrete rails exfoliated and spalled, consistent with condition report.
WSDOT tests/evaluations: ASR detect performed with yellow stain. No reaction, negative for
Routing to Laboratory: Samples were received on November 11, 2004. Report of results is dated
February 2, 2005 identified as CTL Project 153964
CTL Laboratory results
ASR: “No evidence of deleterious alkali-aggregate reaction (such as ASR or related
Aggregate comments: “contains some rock types that are potentially reactive”…No
evidence of reaction”
Deterioration noted: extensive cracking and poor condition attributed to cyclic freezing
and thawing during periods of moisture saturation.”
Air Structure: “not air entrained and therefore not properly protected for frost-related
Site number and description SITE #3 SOUTH FORK TOUTLE, COAL BANKS BRIDGE
Location: (Southwest Region, SR504/MP11.04 11 miles east of Castle Rock
Climate & Weather: Cascade foothills, Moderate to heavy precipitation, mild
Condition Report: Extensive Map Cracking in Concrete Bridge Rails (New Jersey form barrier)
Constructed 1982 under Contract 2129, 22 years old
Materials sources/comments: Concrete aggregate from pit site L 119 near Toledo, moderate
reactivity in sources 10 miles north. Cement from Lone Star, type 2
Date: August 19, 2004, Jeff Donaldson, Don Brouillard, Jeanne Andreasson South west
Region traffic control
Sample types Two 4-inch cores taken from inside face of barrier, North side of structure.
Field observations: Generalized map cracking observed consistent with condition report.
Area sampled seemed to have highest degree of cracking.
WSDOT tests/evaluations: ASR detect test on core, no reaction with yellow stain, Negative for
Routing to Laboratory: Construction Technology Laboratory received core on November 11,
2004. Reported results December 22, 2004, Results reported as CTL Project 153961.
CTL Laboratory results
ASR: ”Petrographic examination …revealed no evidence of deleterious alkali-aggregate
reaction… Cracking exhibited is also not consistent with damage typical of ASR.”
Aggregate comments: “consists of some rocks that are possibly reactive with high-alkali
cement” …”fine grain, siliceous volcanic & metamorphic rocks”
Deterioration noted:” limited fine cracking”,
Air Structure: Air entrained 4.6% air content, spacing factor 0.011 inch
(Desirable air content 6% for severe exposure, spacing factor to be less than 0.008 in.)
“Concrete judged as fair to good with limited fine cracking. Possible cracking mechanism related
to restrained volume changes due to drying shrinkage”
Site number and description SITE #4 COUNTY ROAD OVERCROSSING
Location: South Central Region, SR 124 /MP27.48, 7 miles West of Prescott
Climate & Weather: Eastern Washington, arid, moderate freeze-thaw
Condition Report: 1998 “Deck is ASR candidate, Map cracking in deck, wing walls &
Bridge was constructed in 1962 under contract 6854 and was 42 years old at the time of
Materials sources/comments: Aggregate source identified as Jones/Scott, Cement was Ideal type
October 5, 2004 Jeff Donaldson with traffic control from South Central region.
Sample types two 4-inch diameter cores, 5 inches deep taken from side railing curb.
Taken at low drainage point on structure. (Note this structure had originally (1998) had
description as ASR deficiency in deck. Current condition and records indicate deck was
reconstructed. Concrete sampled should have been representative of original construction
contemporary with deck, which deteriorated.
Field observations Hairline cracks at random.
WSDOT tests/evaluations ASR detect test produced yellow staining indicating positive test for
Routing to Laboratory: CTL received core on November 11, 2004 and reported results on
December 22, 2004 as CTL project 153960.
ASR: “no evidence of an ASR problem. …No deleterious alkali aggregate reaction,
reaction gel, or related damage. Cracking exhibited in the core is also not consistent with damage
typical of ASR.
Aggregate “hard & firm, generally well graded… Basalt, small amounts of fine-grain
volcanic, igneous and metamorphic rocks.”
Deterioration noted Shallowly carbonated, localized minor leaching
Air Structure: Air content 2.0% based on presence of small, spherical bubbles Spacing
factor 0.022 in. For moderate freeze thaw exposure, recommended air content: 5% spacing
factor less than 0.008 in.
Comments: Core sample results do not indicate that ASR was likely as cause of earlier reported
Site number and description: SITE #5 TOUCHET RIVER BRIDGE
Location: (South Central Region, SR 12 /MP319.35 17 miles West of Walla Walla
Climate & Weather Eastern Washington, arid, moderate freeze-thaw
Condition Report: Concrete Bridge Rail Baluster Rails Exfoliated and Spalled. This structure
was built in 1936 under Contract 2241 and was 68 years old at the time of sampling.
Materials sources/comments Aggregate source shown as Jones/Scott Gravel (same as for site
#4), Cement shown as Lehigh HES
Date October 5, 2004, Jeff Donaldson and Traffic Control crew from South Central
Sample types Two 4-inch cores, 5 inches deep taken from Structure end block at low end
Field observations: consistent with condition report. This structure was selected by field
advance visit crew to afford opportunity to sample from exhibited spalling and exfoliated
WSDOT tests/evaluations: ASR detect test resulted in observable yellow staining, indicating
positive test for ASR.
Routing to Laboratory: Received at Laboratory November 11, 2004, Results reported February
3, 2005 as CTL Project 153963
CTL Laboratory results
ASR:” No evidence of deleterious alkali-aggregate reaction (such as ASR) or related
Aggregate comments: Some rock types that are potentially reactive in concrete made with
high alkali cement. No evidence of such reaction”
Deterioration noted: Water-cement moderately high, carbonation to a depth of to 19mm,
“possibly restrained volume changes related to drying shrinkage
Air Structure: Not air entrained due to absence of small, spherical voids. Air content
0.8% spacing factor 0.034 inch: recommended air content 6%, spacing factor not to exceed 0.008
Comments: Concrete visibly rich in paste and water cement ratio likely moderately high, both of
which can promote shrinkage.
Site number and description: SITE #6 METHOW RIVER BRIDGE
Location: (North Central Region, SR153 /MP11.83 12 miles North of Pateros
Climate & Weather Eastern Cascade foothills, Columbia Basin, arid, Medium freeze-thaw
Condition Report Concrete Baluster Rails: sever to moderate delamination throughout. This
condition is identical with a number of other bridges in the vicinity, all constructed under the
same contract and presumably of the same materials. Constructed in 1939 under contract
2450,65 years old at the time of sampling.
Materials sources/comments Concrete aggregate from source U-80, no current information,
Current source in the vicinity, U-271 15 mile south of this structure shows moderate ASR based
on C-1260 results. Cement Source shown as “Northwestern” does not match any source in files.
Date October 20, 2004 Jeff Donaldson and North Central Region Traffic Control Crew &
Sample types:” one 4-inch diameter core, 5” deep from end block.
Field observations: Map cracking and delamination consistent with condition report,
WSDOT tests/evaluations: ASR detect test showed bright yellow reaction product, positive for
Routing to Laboratory Received at CTL on November 11, 2004. Reported results on December
21, 2004, as CTL project No.153958.
CTL Laboratory results
ASR yes/no Significant ASR evident, damage in core somewhat limited
Aggregate comments “Siliceous rocks potentially reactive…chalcedonic chert, fine-grain
siliceous volcanic rocks, quartzite, gneiss and schist.
Deterioration noted: hairline cracks and microcracks, aggregate cracking associated with
Air Structure: Air content 1.2%, non-air entrained, lacking presence of spherical form
bubbles. Spacing factor: 0.032 in. For freeze thaw protection, entrained air content should be
approximately 6% and spacing factor less than 0.008in.
Site number and description: SITE #7 UPRR OVERCROSSING
Location: (Eastern Region, SR 26 MP 102.76 14 miles West of Dusty)
Climate & Weather: Eastern Washington, Arid, Moderate freeze-thaw.
Condition Report: Concrete deck, extensive surface map cracking. This structure was
constructed in 1967 under Contract 8153 and was 37 years old at the time of sampling.
Materials sources: Concrete aggregate from Pit Site C-117. This is a Spokane Valley aggregate
source; material was transported to ready-mix plant in Colfax, WA. Cement from Lehigh, Type
Date October 19, 2004 Jeff Donaldson & Tony Briscoe with Eastern Region Traffic
Sample types: Two 4-inch cores, approximately 2 ½ inches deep plus fragments from
site. Samples taken from lowest drainage area.
Field observations: Bridge condition consistent with condition reports.
WSDOT tests/evaluations No samples were provided to the Chemistry section for the test.
Routing to Laboratory Collected materials may have been determined to be unsuitable for further
CTL Laboratory results No tests on this site
Site number and description: SITE #8, EAST FOSTER CREEK
Location: (North Central Region, SR 17 MP127.23 7 miles west of Leahy)
Climate & Weather: Eastern Washington, Columbia Basin, moderate Freeze Thaw, Semi-Arid
Condition Report: Hairline cracking with some leaching. Structure was constructed in 1950
under Contract 3759 and was 54 years old at the time of sampling.
Materials sources: Concrete aggregate from DO 73 near East Wenatchee. Not a current source,
sources in the vicinity have moderate reactivity. Cement from Northwestern cement, Type 2 No
tests from this source. Other contemporary sources indicate average cement alkalis around
Date: October 19, 2004 Jeff Donaldson & Tony Briscoe with North Central Traffic
Samples: Two 4-inch cores taken from top of end block showing typical map cracking
Field observations: Map cracking consistent with condition report.
WSDOT tests/evaluations: ASR detect test resulted in appearance of yellow stain indicating
positive for ASR.
Routing to Laboratory Samples received at CTL on November 11, 2004. Report completed on
November 22, 2004 and reported as CTL Project No. 153959.
CTL Laboratory results
ASR: Minor ASR noted, traces of reaction gel and apparent reaction rims in a sparse
portion of the aggregate
Aggregate:” Minor portion of each aggregate consists of siliceous rocks that are
potentially reactive. With high-alkali cement. …Chalcedonic chert, fine-grain siliceous volcanic
rocks, quartzite, and gneiss.”
Deterioration noted: Hairline cracks, some corrosion of steel reinforcement.
Air Structure Air entrained, air content 8.3%, Spacing factor 0.005 inch.
Desirable air content for moderate exposure 5%, spacing factor should be less than 0.008
Site number and description SITE #9 OHANPECOSH CAMPGROUND
Location: (Southwest Region, Not on State System, located ¼ mile past entrance to Ohanapecosh
Campground in Mt. Rainier National Park. Approximately 14 miles northeast of Packwood
Climate & Weather: Western Cascade foothills, substantial precipitation, moderate to severe
Condition Report On site observations show general absence of cracking and defects. This
structure was constructed for the National Park Service in 1960. And was 45 years old at the time
Materials sources: No source information available. Speculation is that concrete aggregate may
have come from gravel source in the general area. No information available from NPS/FHWA as
to origin or type of cement.
Date: December 15, 2004, Jeff Donaldson & Tony Briscoe & crew
Sample types: Two 4-inch cores, 5” deep taken from bridge curb at lowest portion from
Field observations: Structure generally absent of deterioration. This site taken as
contemporary with other site of known ASR deterioration (Stevens Canyon Entrance, Site #10).
Subsequent historical information indicates it was constructed later and may have used materials
from different sources than site # 10.
WSDOT tests/evaluations: ASR detect test resulted in no staining of specimen indicating
absence of ASR.
Routing to Laboratory: Received at CTL on January 3, 2005. Results reported as CTLGroup
project 153977 on February 24, 2005.
CTL Laboratory results
ASR yes/no: “Traces of suspected alkali-silica reaction gel but no evidence of damage”
Aggregate comments: 1” top size, fairly good quality, soar rock types potentially
reactive, small amounts of moderately soft rock may produce “pop-outs”
Deterioration noted: ”fairly good condition, No large cracks or abnormal microcracking.”
Air Structure: Air content 0.9%, non-air entrained. Spacing factor 0.036” For freeze thaw
protection air content should be 4 ½ to 6% and spacing factor 0.008’ or less.
“Water cement content estimated to be moderate to moderately low. Concrete in fairly good
condition. No evidence of damage related to cyclic freezing and thawing.”
Site number and description: SITE # 10 STEVENS CANYON ENTRANCE
Location: (Southwest Region, Not on State System Located at Stevens Canyon entrance to Mt.
Rainier National Park. Approximately 14 miles NW of Packwood, WA)
Climate & Weather Western Cascade foothills, substantial precipitation, moderate to severe
Condition Report: On site observations show extensive map cracking with exudated materials.
Structure has been identified as deteriorated due to ASR. and was a part of an investigation
performed by AMEC in 2001 for the National Park Service. Under that study, concrete for the
backbone Ridge Viaduct was determined to have active ASR deterioration. This structure was
built in 1956 and was 38 years old at the time of sampling.
Materials sources/comments: No source information available. Speculation is that concrete
aggregate may have come from gravel sources in the general area. No information available from
NPS/FHWA as to origin or type of cement.
Date: December 15, 2004 Jeff Donaldson and Tony Briscoe
Sample types: Two 4-inch diameter cores taken for end block at lowest drainage end of
Field observations Map cracking extensive with white efflorescence/exudates evident.
WSDOT tests/evaluations: Positive test for ASR with ASR detect test on removed sample of
Routing to Laboratory: Samples were received at CTL on January 3, 2005 and results were
reported on February 24, 2005 under CTLGroup project No 153978
ASR yes/no: “Significant amount of ASR and related damage attributed to porphyritic
and partially glassy volcanic rocks in coarse & fine aggregate.”
Aggregate comments: “a variety of igneous and meta-sedimentary rocks, primarily fine to
medium grain, silicified and altered volcanic and volcaniclastic rocks…”
Deterioration noted: Hairline cracks common to abundant, deposits of reaction gel and
calcium rich leachate”
Air Structure: Unable to quantitatively determine due to degree of deterioration.
Apparently not air entrained based on visual examination.
Site number and description: SITE # 11: BELLINGHAM VICINITY SR 5 SOUTHBOUND
Location: (Northwest Region, SR 5 MP254.60 South bound lanes South of Bellingham,)
Climate & Weather: Western Washington, Puget sound margin, significant precipitation, and
Condition Report: Pavement in this half-mile segment vicinity shows lateral cracking following
retrofit project. Upon coring, lower portion of cores show cracking and deterioration.
Materials sources/comments: Contract was identified as #6249, original construction in 1961.
Request to Pavement Design section and to project office produced no specific information
relative to sources of either concrete aggregates or Portland cement used on this project
Aggregate source identified generically as Nooksack river gravel. Project records for this
segment reported as lost in office fire. .
Date: August 24, 2004, Jeff Peterson from Mark Russell’s PE office took full depth
cores from the section.
Sample types: Ten 4-inch cores taken, two (cores # 2 & 4) selected for further study
Field observations: Panel cracking has developed in this ½ mile section following
completion of dowel bar retrofit project in 2003.
WSDOT tests/evaluations: ASR detect test negative for reaction on both cores>
Routing to Laboratory Samples received by CTL on January 3, 2005. Report
prepared February 25, 2005. CTL report identifies these samples erroneously as
“Taken from a concrete pavement on the Everet (sic) River Bridge”. Two reports
were provided: CTL Project 153979 covers core 2, CTL Project 153980 covers
core 4. Reports below are a composite of the two reports.
ASR yes/no : Core 2: no evidence of aggregate alkali reaction. Core 4 same comments
Aggregate comments: Core 2 1 ¼” top size, hard firm & durable some potentially
reactive rock types. Core 4: 1 ½” top size, Same comments as Core 2
Deterioration noted: No visible cracking or distress. No evidence of damage related to
cyclic Freeze-Thaw Core 2 slight carbonation on top surface. Core 4 same comments.
Air Structure: Core 2 2.5% entrained Spacing factor 0.008”
\ Core 4: Air content 4.5%, entrained, spacing factor 0.008”
“For 1 ½” top size should be air entrained to 4 1/2 to 5 1/2% range. Spacing factor should
be 0.008” or less”
General Laboratory comments described these samples as fairly dense, hard, and strong
indicative of concrete placed with a moderately low water-cement ratio.
PHOTOGRAPH PAGE NUMBER 1
Site 1 5/537S at Spokane Street Site 3 504/10 South Fork Toutle River Coal Banks
Deterioration not ASR related Deterioration not ASR related
Site 8 17/306 East Foster Creek Site 9 Ohanapecosh Campground
Minor ASR present, not cause of deterioration Deterioration not ASR related
PHOTOGRAPH PAGE NUMBER 2
Site 2 101/266 Duckabush River - Deterioration not ASR related
Site 6 153/10 et. al. Methow River ASR related deterioration typical of multiple bridges
Site 10 Stevens Canyon Entrance Confirmed ASR deterioration
Relative to the subtasks of this study comments are as follows.
Standards & Specifications
The total operation of the existing specifications is at variance with process outlined in
the referenced ASTM and AASHTO standards in that a qualitative determination of possible
reactive materials is utilized to negate a demonstrated potential reactive performance.
The results of the conducted survey indicate that there is some lack of understanding at
the project level as to the procedure to follow concerning concrete aggregate and mix approval.
No records of approved mitigation were found at the Laboratory even though the project advised
that they were forwarded. This may be a result of the recording and documentation practices or
actually reflect imperfect knowledge at the field level.
Reliance on contractor/supplier submission to document mitigation and further
investigations leaves several unanswered questions. There is not a clearly defined origin and
traceability of the materials involved. Qualifications of the testing services are unconfirmed.
Identification of unsatisfactory test results is absent.
A level of risk approach, similar to the Canadian practice, offers possibilities for
improvement of standards & specifications.
ASR Detect test procedures are a reasonable cost process that is capable of field
Cement Supply History
Current production is providing cement with alkali levels generally in conformance with
the requirements for low alkali cement.
Historical records indicate that cement alkali levels have generally been at or below
It cannot be excluded that there may have been sources or contract specific supplies of
materials that did in fact exceed the historic levels documented by test. Specific cement source
information is absent for the projects exhibiting ASR deterioration.
Fly Ash Supply History
Records indicate that alkali levels tend to increase in recent production.
Alkali level of fly ash is not a complete indication of its ability to mitigate ASR
occurrence. Inhibiting mechanism is not well understood and performance as an ASR-mitigant
may be better determined by use of established performance tests such as ASTM C 441.
• Aggregate Source Reactivity
Classification of aggregate acceptability is somewhat unclear due to interpretation of
precedence of test procedures. Some sources may be considered as acceptable, based on
chemical composition, when further investigation of reactive potential might indicate different
Considering relative reactivity of aggregate based on comparison of results from ASTM
C 1260 is valid since test results in the data record come from WSDOT Materials Laboratory
testing on samples obtained by WSDOT regional IAI staff.
General trends of reactivity can be determined from the distribution map (Figure 1) for
results. These might be used to indicate special areas of concern but are not adequate to rule out
any locale from possible presence of reactive aggregate.
Project information records
Structural project records for WSDOT/WSDH work will generally yield identification of
Based on the experience in this study, defect descriptions in the Bridge Condition survey
system identify surface appearance. They are not attuned to identify underlying causes of
Candidate project identification
Original study objective referring to “recent” construction was not really appropriate to
the subject. ASR deterioration is a process reflecting significant time for development. Most
“recent” projects considered, based on defect descriptions, were twenty years old or greater.
Project identifications and reference data are contained in both the candidate project
tables and in the Sample sites compilations.
Project Study Plan
The plan developed was reviewed and concurred with by WSDOT as an initial guide for
Modifications were made to better suit the actual logistics and operation considerations.
This included need to recognize capabilities of coring equipment and factoring equipment
capabilities into the sampling procedure.
Competence/experience of the testing service employed (Construction Technology
Laboratory) was a key factor in credibility of the results provided. Workload involved by this
source did influence availability of final test information.
Final test results
• ASR (Alkali-Silica Reactivity):
The aggregates encountered all exhibited some content of potentially reactive
The ASR detect test performed at the Materials Laboratory indicated possible
aggregate reaction that was not confirmed by the CTL petrography for some sites. These were
site #4 County Road Over crossing and Site #5Touchet River Bridge. They had a common
aggregate origin and the presence of potentially reactive materials was noted however no active
ASR was found by CTL.
Only one WSDOT-constructed structure, Methow River, had deterioration
attributable to development of aggregate-alkali reaction. One additional structure, Foster
Creek, showed some lesser development. The ASR detect test on Foster Creek found possible
alkali-silica reaction, which agreed with CTL findings.
Regardless of the level of apparent deterioration and age, other WSDOT
structures did not exhibit defects attributed to ASR.
• Concrete structure performance
Considerable credibility should be given to CTL comments as to possible
construction related considerations. Particularly related to the Spokane Street connection,
comments based on the sampled material reflect serious departure from good construction
practice (segregated, high w/c ratio, lack of entrained air). Other CTL comments attribute the
observed cracking to possible higher water-cement ratio or to possible drying shrinkage.
• Field use of ASR detect test
The ASR detect test would be adaptable for use on field sites. It would allow sampling
from areas not readily available to coring equipment and require moderate support equipment.
Operator training should be relatively straightforward and documentation of results by color
photography would seem reasonable. These features would support the use of this technology if
it were desired to sample a greater number of sites than was done in this study. It might also be
considered for a program to statistically select more samples from the bridge system if there is an
interest in expanded study of ASR occurrence.
Based on the study conducted it was concluded that:
Potentially Alkali-silica reactive aggregates are present to some degree in all the
structures investigated although ASR deterioration is not present. The historical use of Portland
cement with an alkali level below the definition limit for Low Alkali (Type 5) cement
contributes to this performance. This should support the continuance to address this aspect of
performance in qualifying concrete aggregates.
Considering the selective submissions possible under the present aggregate qualification
program, efforts should be directed to enhance the information in this record.
The general history of relatively low alkali-equivalent content in Portland cement used on
WSDOT contracts probably contributes to the low incidence of reactivity-associated
deterioration. This history should be utilized to establish continued utilization of low-alkali
Evaluation of reactivity and determination of appropriate mitigation methods should be
by individuals qualified and experienced in such disciplines. NRMCA (National Ready Mix
Concrete Association) programs offer training in design and interpretation of concrete mix
parameters. Those making determinations of suitability of aggregates and mix mitigation
measures should have this or equivalent expertise specifically related to concrete mix design.
The general performance level of concrete structures, based on the limited but
representative sample in this study, does not indicate widespread ASR related deterioration. The
potential does exist, however. A graded, risk-based approach could offer assurance that high-
value critical performance structures receive appropriate attention while offering an economic
alternate for lower risk projects.
400 B. Recommended Revisions To Standards And Specifications
Revision of Standard specifications
1. Eliminate the use of petrographic analysis to negate reactivity disclosed by
test. Petrographic analysis, performed by a laboratory with a minimum 5-year
history in the technique, should be considered as the initial measure in
qualifying a source. Recommendations from the laboratory for further review
of the aggregates should be binding. If compositional limits are continued,
exceeding the specified values should be the basis for presumption of
reactivity and mandatory mitigation.
2. Consider a three level indication of action based on AMBT (ASTM C 1260)
results. Low reactivity (0.20% expansion or less) allows for use all but
extremely critical structures. Medium reactivity (0.21 to 0.45% expansion)
require use of low alkali cement (0.60 equivalent alkalis maximum) or
inclusion of 25% Class F fly ash in Cementitious materials, High reactivity
(expansion exceeding 0.45% or exceeding compositional limits) require
demonstrated effectiveness of proposed mitigation measures. Relief of
requirements imposed for Medium and High categories would be by
consideration of results from ASTM C 1293.
3. Develop a standard for Concrete for “Extremely Critical” applications. Such a
standard would require demonstration of performance of the concrete mix
proposed for use with respect to aggregate reactivity. Structure qualification
could include all structures immersed in water (floating bridges) or subject to
immersions or saturation and having operational criticality to integrity of a
high traveled route such as a major interstate. Such structures as Alaskan Way
viaduct, Aurora Street, Ship Canal structures on SR 5, Columbia River
crossings and Hangman Creek Crossing in Spokane come to mind in addition
to the floating bridges. The Canadian Standards approach, which further
incorporates limits on cement alkalis in the concrete mix, should be
Revisions of Administrative measures
1. Ensure integrity of aggregate performance determinations; Require
sampled material .to have a chain of accountability for sampled
aggregate, beginning with verification by WSDOT staff of the physical
origin of the materials, continuing through transmission and
requisition of necessary processing and testing to receipt of test
information. Require that all test reports be in full compliance with all
requirements of the applicable test procedure and bear the signature of
a responsible party.
2. Establish formal qualifications for evaluation laboratories and
aggregate source review personnel. Suggested requirements would be:
For the evaluating laboratory, a 5 –year history of performance of
the required test procedure. (Note: there is at present no accreditation
process (CCRL or equivalent) in these tests).
For reviewing personnel, completion of the NRMCA mix
technology course or equivalent
3. A general review of the ASA database to ensure agreement with
physical and legal descriptions of location, examination of pertinence
of auxiliary comments and comparison of listed qualifications with test
data on which they were based. Consideration should be given to
electronically incorporating qualifying results and mitigation measures
approved in the ASA record.
REFERENCES AND SOURCES UTILIZED
1. FHWA/ACI Course Materials for “Concrete Durability: ASR and other Deterioration
Mechanisms” Reference is comprised of two binders including class notes and was
obtained form a presentation held in September 2001 at the Materials Laboratory. This
reference includes a comprehensive bibliography and extract copies of standards and
methods, particularly the Canadian Standards Association (CSA) standard practice for
2. FHWA-RD-03-047, Guidelines for the use of Lithium to Mitigate or prevent ASR, report
dated July 2003. The initial chapters provide an excellent concise discussion of the ASR
mechanism. This report also contains an extensive bibliography that was used as a further
guide to pertinent information.
3. AASHTO Guide Specification for Highway Construction SECTION 56X Portland
Cement Concrete Resistant to Excessive Expansion Caused by Alkali Silica Reaction
obtained from AASHTO Innovative Technologies web site July 2004.
4. Thomas, M.D.A, and Innis F.A (1999) “Use of the accelerated mortar bar test for
evaluating the efficiency of mineral admixtures for controlling expansion due to alkali-
silica reaction” Cement, Concrete and Aggregates, Vol. 21 (2) pp. 157-164
5. Shehata M. H and Thomas M>D.A. (2000) The effect of fly ash composition on the
expansion of concrete due to alkali-silica reaction,” Cement and Concrete Research Vol.
30, 2000, pp. 1063-1072
6. Proceedings, 11th International Conference on Concrete and Aggregates (11th ICAR)
a. Note: This reference was obtained on CD from Jeff Uhlmeyer and contains a
number of state-of-the-science papers. Included in this compilation which cannot
be retrieved at this time is a proposal for allowing the limit on expansion for use
of aggregates otherwise satisfactory to rise to 0.20% based on ASTM C 1260, 14
day results and on which the proposal in the Recommendations section is based.