The following suite of tools help with characterization of cracking and rutting of asphalt pavements.

FlexMAT for Cracking

FlexMAT for Cracking is a Microsoft® Excel-based analysis tool for characterizing dynamic modulus and cracking of asphalt pavement mixtures from Asphalt Mixture Performance Tester (AMPT) test results. This includes determining the 2S2P1D dynamic modulus master curve coefficients and time-temperature shift factors. It analyzes the AMPT cyclic fatigue test results (AASHTO TP133) to provide inputs to FlexPAVE™ cracking evaluation. These inputs include damage characteristic curve coefficients, failure criteria coefficients, ageing parameters, and the coefficient of thermal contraction. The analysis also supports balanced mix design and production evaluation by calculating the S_app  index cracking parameter from the test data.

Additional information can be found in the TechBrief, Cyclic Fatigue Index Parameter (Sapp) for Asphalt Performance Engineered Mixture Design, 2019. (FHWA-HIF-19-091).

FlexMAT Cracking v2.1.1.xlsm (file): Actual FlexMAT v2.1.1 file, cracking analysis version, ready for testing using the new universal data structure format requirement.

FlexMAT for Rutting

FlexMAT for Rutting is an Excel-based analysis tool for characterizing rutting of asphalt pavement mixtures from AMPT test results. This includes analyzing the AMPT stress sweep rutting (SSR) test results (AASHTO TP134) to provide shift permanent deformation model coefficients to FlexPAVE rutting evaluation. The analysis also supports balanced mix design and production evaluation by calculating the Rutting Strain Index (RSI) parameter from the test data.

Additional information will be available in the TechBrief, Rutting Strain Index (RSI) Parameter for Asphalt Balanced Mixture Design. (FHWA-HRT-21-044).

FlexMAT Rutting v2.1.1.xlsm (file): Actual FlexMAT v2.1.1 file, rutting analysis version, ready for testing using the new universal data structure format requirement.

Climatic Data Files

Use .csv files with the FlexMAT Rutting v2.1.1 analysis tool to successfully perform the asphalt pavement rutting analysis. This set of files includes an expanded MERRA2 temperature database from 2,798 locations across the United States, and 20 years (1996–2015) of temperature information.

"Rutting Climate Files.zip" (files): Contains the updated temperature database required for RSI calculations in FlexMAT v2.1.1 for Rutting.

Extract the .csv files within the .zip file into a folder. If the folder is inside the same overarching folder as the FlexMAT Rutting v2.1.1 file, it will be automatically identified. If not, the user will be prompted to identify the folder’s location.

Data Structure Requirement Documents

Use these three documents to understand the AMPT test data and universal format required for FlexMAT to successfully import the test data and conduct the analysis. Each document will show the required data format the equipment manufacturers must use and report from their test equipment. These universal requirements allow the test data to be directly imported into FlexMAT from the equipment. If your equipment is not reporting data in the specified format, use these documents to verify requirements with the manufacturer:

"FHWA-HRT-21-054 FlexMAT™ Asphalt Dynamic Modulus.pdf" (file): Contains the FlexMAT-specified data structure for the dynamic modulus test using the AMPT. The test data output must follow the data structure for import to FlexMAT.

"FHWA-HRT-21-055 FlexMAT™ Asphalt Cyclic Fatigue.pdf" (file): Contains the FlexMAT-specified data structure for the cyclic fatigue test using the AMPT. The test data output must follow the data structure for import to FlexMAT.

"FHWA-HRT-21-056 FlexMAT™ Asphalt Stress Sweep Rutting.pdf" (file): Contains the FlexMAT-specified data structure for the stress sweep rutting test using the AMPT. The test data output must follow the data structure for import to FlexMAT.

Upon exporting files from the equipment, users should not open or modify the files using text editors or Microsoft® Excel because such operations may corrupt the files and make them unreadable in FlexMAT.

Example Test Data Report Files

Use these files as examples of test data output files from the equipment that adhere to the universal data structure requirements to successfully use and analyze the data in FlexMAT.

"Input Examples" (folder): Contains dummy examples of Dynamic Modulus, Cyclic Fatigue, and SSR tests in new (universal) formats (compatible with FlexMAT v2.1.1).