摘要: |
One of the major distresses that occur to Asphalt Concrete (AC) is fatigue cracking. It is believed that fatigue cracking occurs due to repeated traffic loading which induce high tensile stresses at the bottom of the asphalt layer. Recently, pavement engineers and researchers have expressed great concern over the cracking of flexible pavements under various traffic loading and environmental conditions. The development of a quality control test that is simple to conduct, inexpensive to perform and requires no new equipment is investigated in this proposal. The assessment of the developed test is conducted through statistical correlation with a more complex, more expensive and requiring more equipment test. The main objectives of this proposal are to investigate the use of the Semi Circle Bend (SCB) test as a quality assurance/control (QA/QC) measure for field construction; statistically compare the results of the SCB with the current Fatigue Beam Test (FBT); and investigate the influence of various environmental and mixture variables on the results. The experimental factorial is designed to cover variables that are believed to affect the fracture properties of asphalt mixtures. These variables include binder type and specimen type. Two commonly used binder types are considered. Specimens with different compaction methods including gyratory compactor and kneading compactor are used. In addition two fracture properties tests are performed, SCB, and FBT. The outcome of this research will result in the many benefits including, reduced reflective cracking in asphalt overlays, reduced maintenance costs, improved resistance to cracking in new pavements, and increased pavement life. This research proposal focuses on fracture performance properties of asphalt mixtures and provides performance testing for fatigue cracking that can be used in quality control/assurance (QC/QA) evaluation methods. The results of the proposed work could also be used to modify the current specifications used in the State of California. |