Long Term Pavement Performance Project Laboratory Materials Testing and Handling Guide

Protocol P28
Test Method for Determining The Flexural Creep Stiffnessof Asphalt Binder Using The Bending Beam Rheometer (BBR) (AE08)

This LTPP Protocol covers the procedures for determining the flexural creep stiffness of asphalt binders using a bending beam rheometer (BBR). The test shall be carried out in accordance with AASHTO T313-02 as described by the following.

12. PROCEDURE

12.1 Select the test temperature based upon the laboratory testing plan designed for the individual SPS project. After demolding, immediately place the test specimen in the testing bath and condition it at the testing temperature for 60 ± 5 minutes.

14. REPORT

Sample Identification shall include: Laboratory Identification Code, LTPP Region, State, State Code, SHRP ID, Layer Number, Field Set Number, Sample Area Number, Sample Location Number, and LTPP Sample Number.

Test Identification shall include: LTPP Test Designation, LTPP Protocol Number, Laboratory Test Number, and Test Date.

General test and sample information:

14.3.1 Material type should be stated as Original, RTFO, PAV, or Field Aged.

14.3.2 In case of field aged, specify the time the sample has aged since construction, in months.

14.3.3 Minimum and maximum test temperature, in degree Celsius.

14.3.4 Soak time, in minutes.

14.3.5 Beam width, in millimeters.

14.3.6 Beam thickness, in millimeters.

14.3.7 Preload, in millinewtons.

14.3.8 Seating load, in millinewtons.

14.3.9 Seating load time, in seconds.

14.3.10 Recovery time, in seconds.

14.3.11 AC performance grade.

Summary of results

For every loading time (8, 15, 30, 60, 120, and 240 seconds), report:

14.4.1 Time, in seconds.

14.4.2 Force, in newtons (record force at 0 and 5 seconds also).

14.4.3 Deflection, in millimeters (record deflection at 0 and 5 seconds also).

14.4.4 Stiffness, measured and estimated, in megapascals.

14.4.5 Percent of difference between measured and estimated stiffness values.

14.4.6 Estimated m value. (See section 3.2.4 of AASHTO TP1-98 for definition)

14.4.7 Regression coefficients:

Regression constant A
Regression constant B
Regression constant C
Correlation coefficient, R²

14.5 Comments shall include LTPP standard comment code (s) as shown in Section 4.3 of this Guide, and any other note as needed.

Raw data from the BBR device should be included.

LTPP LABORATORY MATERIAL HANDLING AND TESTING
LABORATORY MATERIAL TEST DATA
FLEXURAL CREEP STIFFNESS OF ASPHALT BINDER
USING THE BENDING BEAM RHEOMETER
LAB DATA SHEET T28

ASPHALT CONCRETE LAYER (ASPHALT CEMENT PROPERTIES)
LTPP TEST DESIGNATION: AE08/LTPP PROTOCOL P28

LABORATORY PERFORMING TEST:____________________________________________________________

LABORATORY IDENTIFICATION CODE:__ __ __ __

REGION:_________________ STATE:__________________ STATE CODE: __ __

EXPERIMENT NO:_____ SHRP ID: __ __

SAMPLED BY:____________________________________________ SAMPLE AREA No: SA-__ __

DATE SAMPLED:__ __-__ __-__ __ __ __ FIELD SET NO.: __

LAYER NUMBER (FROM LAB SHEET L04 AND FORM T01B)__

SAMPLE LOCATION NUMBER__ __ __ LTPP SAMPLE NUMBER__ __ __ __

LABORATORY TEST NUMBER:__ TEST DATE:__ __-__ __-__ __ __ __

1. Material type (Original = 1, RTFO = 2, PAV = 3, Field Aged = 4) __

2. fOR field aged, time since construction, months __ __ __.__

3. MAX Test temperature, °C __ __.__

4. MIN Test temperature, °C __ __.__

5. Soak time, s __ __ __ __.__

6. Beam width, mm __ __.__ __

7. Beam thickness, mm __ __.__ __

8. Preload, mN __ __

9. Seating load, mN __ __ __ __

10. Seating load time, s __ __

11. Recovery time, s __ __

12. AC performance grade PG __ __-__ __

13. Summary of results

14. Regression coefficients

A = __ __.__ __ __ B = __ __.__ __ __ C = __ __.__ __ __ R² = __.__ __ __

15. COMMENT CODEs __ __ __ __ __ __ __ __ __ __ __ __

16. NOTE: Please attach the raw data from bending beam rheometer device