|Project Name:||Application of Laser Shearography to Asphalt Issues|
Office of Infrastructure Research and Development |
|Team:||Pavement Materials Team|
Infrastructure Research and Technology Strategic Plan and Roadmap|
|Project Description:||Develop quality assurance/quality control (QA/QC) testing equipment and methodology and develop test procedure(s) for conducting noncontact strain measurement at the pavement surface and of asphalt mixtures (cores).|
Pavement Testing Facility|
Bituminous Mixtures Laboratory
|Start Date:||October 1, 2012|
|End Date:||May 31, 2015|
|Goals:||The key project objective is to apply the sensitivity of laser shearography in measuring shear deformations to the development of new test methods for asphalt binders, asphalt mixes, and pavements.|
|Background Information:||Current quality assurance/quality control (QA/QC) testing of asphalt binders is conducted long after the completion of the project. The Federal Highway Administration's (FHWA's) goal is to develop a rapid test procedure for conducting onsite QA/QC testing of the binder. An added advantage of this test is that the sample is not disturbed in its preparation for testing. This allows researchers to study steric and physical hardening phenomenon. Current strain measurements of asphalt cores are conducted using strain gages. The goal is to develop a noncontact strain measurement of asphalt mixtures (cores). Current strain measurements of pavements are conducted using strain gages embedded in the pavement. The Federal Highway Administration's (FHWA's) goal is to develop a test procedure for conducting noncontact strain measurement of asphalt pavements.|
|Test Methodology:||A prototype device is being developed. A diverse suite of modified and unmodified binders with known rheological master curves will be tested on this device. Responses from a quality assurance/quality control (QA/QC) test device will be compared with rheological data. The equipment will be modified to address any issues that might arise, and additional testing will be performed. Finite element modeling (FEM) will be concurrently conducted to validate this approach. A prototype device will be developed to measure minute deformations and possible crack formation of specimens subjected to push-pull testing. Modeling will be conducted such that the shear deformations can be related to strain measurements. The device developed will be used to evaluate the deflection basin at the Accelerated Load Facility (ALF) and assess deformations in the ALF pavement sections.|
|Expected Benefits:||The expected benefit is rapid verification of asphalt binder quality assurance/quality control (QA/QC).|
|Deliverables:||1. Name: Asphalt binder quality assurance/quality control (QA/QC) equipment and test.|
Product Type(s): Research report, Hardware, Draft standard, specifications, or guidelines
Description: The deliverable is a rapid test procedure for evaluating asphalt binders in a sample tin.
2. Name: Noncontact displacement measurement of asphalt cores and pavements.
Product Type(s): Research report, Hardware, Article
Description: The deliverable is a test procedure for conducting noncontact strain measurement at the pavement surface and of asphalt mixtures (cores).
Maintenance and Preservation|