Short-Term Performance of Modified Stone Matrix Asphalt (SMA) Produced with Warm Mix Additives

Abstract

The short-term performance of the stone matrix asphalt (SMA) prepared with various warm-mix techniques (Evotherm™ 3G, Sasobit®, and foamed asphalt) was conducted using extensive laboratory tests and on-site stiffness measurement. The laboratory tests included the complex modulus, flow number, loaded wheel track, indirect tension (IDT) creep and strength, and semi-circular beam (SCB) fracture. In the laboratory tests, plant-produced mixes were compacted in the laboratory with and without reheating, and performance tests were conducted at various curing time periods after compaction. In addition, light weight deflectometer (LWD) tests were conducted to monitor the in-situ pavement stiffness development of the warm SMA field sections. This study concludes that SMA containing different warm mix asphalt (WMA) additives show comparable performance with the control SMA. Both laboratory and field test results do not indicate any evidence that a longer curing time is needed before allowing traffic on warm SMA pavements. The mixtures containing WMA additives show similar variations in mixture properties due to curing time compared to the control SMA. The reheating process causes asphalt mixtures to have greater modulus, tensile strength, and rutting resistance, but smaller creep compliance and fracture resistance. The aging effect due to reheating is more significant on the control mixture than the three warm SMA mixtures due to a higher reheating temperature. An approach to determine the time for opening paved road to traffic is proposed for the tested materials.