Presentation to AMAP

							DETERMINING EMULSION BOND
STRENGTH USING THE BITUMEN
 BOND STRENGTH (BBS) TEST



       Presented by:
      Dr. Terence Milne

       Tuesday, 12 October 2010
Authors

• Timothy Miller, University of Wisconsin –
  Madison, USA
• André Greyling, University of Stellenbosch,
  South Africa
• Prof. Hussain Bahia, University of
  Wisconsin – Madison, USA
• Prof. Kim Jenkins, University of
  Stellenbosch, South Africa

               Tuesday, 12 October 2010
Presentation Overview

• Introduction

• Test method development

• Results and analysis

• Findings and recommendations
                 Tuesday, 12 October 2010
Introduction
• Global trend changes in road construction
  motivated by:
  – Growing mobility demands
  – Enhanced environmental sensitivity
  – Financial constraints


• Move towards Performance Grading (PG)
  specifications for bituminous products and
  more scientific designs processes .
                 Tuesday, 12 October 2010
Introduction
• Identify the need for an inexpensive test
  method to measure bond strength between
  bituminous binders and aggregates.

• Utilize the Pneumatic Adhesive Tensile
  Testing Instrument (PATTI) for evaluating
  bond strength development.

• Propose Bitumen Bond Strength (BBS) test.


                Tuesday, 12 October 2010
Bitumen Bond Strength (BBS) test

• Partners in test method development include
  the University of Wisconsin – Madison, the
  University of Ancona – Italy and the
  University of Stellenbosch – South Africa.

• Characterize moisture sensitivity and bond
  strength development in hot-applied binders
  and bitumen emulsions, respectively.


                Tuesday, 12 October 2010
Research Objectives
• Develop test method to quantify bond
  strength development in emulsified binders.

• Evaluate factors that significantly affect bond
  strength development.

• Consider test parameters, aggregate and
  emulsion materials, curing conditions, and
  curing time in experimental design.
                 Tuesday, 12 October 2010
Presentation Overview
• Introduction

• Test method development

• Results and analysis

• Findings and recommendations
                 Tuesday, 12 October 2010
Test Method Development
• Build on previous work by Youtcheff & Aurilio,
  Kanitpong and Meng.

• Utilize Pneumatic Adhesive Tensile Testing
  Instrument (PATTI), model Quantum Gold.

• Develop bitumen bond strength (BBS) test
  protocol.

• Validate with existing laboratory test method.
                 Tuesday, 12 October 2010
Test Apparatus

                                                     Graded
                          Rate
                          Control
                                                   Scale for Air
                                       Test
                                                    Flow Rate
                     Reaction
                     Plate
                                      Button         Control
     Loading         Piston
     Direction
                     Pull-out Stub
                     Ring Support
                  Test
Substrate        Sample
                                                      Top View
       PATTI Quantum Gold

                                Tuesday, 12 October 2010
Test Assembly Schematic




 Response variable is pull-out tension (psi).
               Tuesday, 12 October 2010
BBS Test Stub Geometry




                                      Dimensions in mm.


           Tuesday, 12 October 2010
Validation: ASTM D7000 Sweep Test




  Response variable is aggregate loss (%).
               Tuesday, 12 October 2010
Presentation Overview
• Introduction

• Test method development

• Results and analysis

• Findings and recommendations
                 Tuesday, 12 October 2010
  Effect of Load Control


• Loading rate is critical
  factor, used to
  calibrate apparatus.

• Appropriate loading
  rates defined for
  subsequent testing.



                     Tuesday, 12 October 2010
Effect of Curing Conditions: Temperature
  35 °C, 70 % Humidity                 15 °C, 70 % Humidity




                  Tuesday, 12 October 2010
Effect of Curing Conditions: Humidity
 35 °C, 30 % Humidity                 35 °C, 70 % Humidity




                  Tuesday, 12 October 2010
Effect of Modification
• 3 CRS binders:
  – CRS-1HP, CRS-2,
    CRS-2P

• 2 substrate types:
  – Granite and
    limestone

• Differences seen in
  modification

                  Tuesday, 12 October 2010
Effect of Materials: Substrate Type
• Longer curing
  intervals (2-48 hr.)

• 3 substrate types:
  – Aggregate plates
  – Chip substrates
  – Glass (control)

• Aggregate plates
  perform best

                   Tuesday, 12 October 2010
Effect of Materials: Emulsion Type
• Five emulsion types:
  – 2 CRS-2 types,
    CRS-2P, HFRS-2,
    HFRS-2P

• Differences between
  types, especially at
  longer curing intervals

• CRS-2, CRS-2P >
  HFRS-2, HFRS-2P
                 Tuesday, 12 October 2010
   Test Method Validation

• Correlations between BBS
  and sweep test are strong
  (R2 > 0.996).

• Relationship incorporates
  different aggregate and
  emulsion types.

• Initiate discussion of
  specification limits.
                      Tuesday, 12 October 2010
Presentation Overview
• Introduction

• Test method development

• Results and analysis

• Findings and recommendations
                 Tuesday, 12 October 2010
Main Findings
• The BBS test is a simple, effective test
  method that can characterize the
  behavior of materials commonly used in
  chip seal surface treatments.

• The method shows promise at being
  integrated into a performance-based
  specification system.
               Tuesday, 12 October 2010
Main Findings
• Material response is heavily dependent
  on loading rate. Rate control is critical
  for achieving repeatable results.

• Test method quantifies the effects of
  emulsion type, substrate type, and
  curing time on the development of bond
  strength.
               Tuesday, 12 October 2010
Future Research Required
• Standardize substrate preparation
  procedures.

• Explore further binder-aggregate
  compatibility with more emulsion types.

• Incorporate testing from other labs to
  develop precision and bias statement.
               Tuesday, 12 October 2010
Future Research Required
• Develop field-based performance tests
  for improved characterization of early
  life behavior.

• Pursue standardization of test protocol
  via AASHTO. A draft procedure is
  currently under review.

               Tuesday, 12 October 2010