Recommended Resolutions to Selected Hot Mix Asphalt Related Issues

摘要

Specific objectives of this project included: (1) Develop laboratory protocols for using the Superpave gyratory compactor (SGC) instead of the Texas gyratory compactor (TGC) (Tex-204-F) to design essentially all of the TxDOT dense-graded HMA paving mixtures. (2) Identify and validate laboratory test protocols for measuring rut susceptibility of HMA mixtures. (3) Identify the best available laboratory test protocol(s) for predicting moisture susceptibility of HMA paving mixtures. (4) Determine the effect of aggregate angularity and nominal maximum size of siliceous river gravel aggregates on performance of selected HMA surface pavement mixtures. That is, investigate whether it is better to use smaller nominal maximum aggregate size (NMAS) with higher coarse aggregate angularity (CAA) (i.e., more crushed faces) or larger NMAS with lower CAA. (5) Measure as-built properties of test pavements and populate a database to be used in a future project for evaluating relationships between pavement performance and measured properties during construction. (6) Obtain and measure certain properties of several plant-produced mixes for production verification and lab-compacted plant mixes to develop a mixture database for use in evaluating the forthcoming mechanistic-empirical pavement design guide. All of the activities and recommendations from this comprehensive research project cannot be discussed in this summary report.