Asphalt Mixture CTE Measurement and the Determination of Factors Affecting CTE

The coefficient of thermal contraction or expansion (CTE) of asphalt mixtures is a property that describes how asphalt mixtures respond to thermal loading during cooling or heating. The CTE is an important mixture property used as an input parameter in the thermal cracking model of the AASHTO Mechanistic Empirical Pavement Design Guide software. CTE measurement has proven quite a challenging task; however, many researchers have developed various methods for measurement using linear variable differential transducers (LDVTs), which have proven robust and suitable for routine tests. In this paper, a laboratory test method was devised using LVDTs to measure the CTE and determine the asphalt mixture properties affecting the CTE. The mixture properties investigated in this study included binder grade, binder content, the presence of recycled asphalt pavement (RAP) and recycled asphalt shingles (RASs), compaction effort, aggregate CTE, and size and aging. Mixture properties such as binder grade, binder content, aging, and the inclusion of recycled materials (RAP and RAS) resulted in a significant change in the CTE and the glass transition temperature (T-g) of mixtures. (C) 2017 American Society of Civil Engineers.