Study on the thermal regulation performance of steel slag ultra-thin wearing courses combined with phase change materials: Towards green and low-carbon applications

Abstract

As urban heat island effects intensify, the advancement of green and low-carbon technologies in road construction has become a key priority in urban development. This study focuses on enhancing the thermal management performance of steel slag ultra-thin wearing courses by evaluating the suitability of composite phase change materials (CPCM), including stearic acid/adipic acid/sebacic acid (SAS) and stearic acid/myristic acid (SM), for incorporation into high-viscosity asphalt (HVA). A series of laboratory experiments were conducted by preparing high-viscosity modified asphalts with varying CPCM contents. The tests included analyses of thermophysical properties, chemical structure, and rheological characteristics. Additionally, the cooling behavior of the composite pavement was characterized. Furthermore, the cooling effects of CPCM on both the steel slag ultra-thin wearing course and the underlying pavement structure were analyzed. The findings indicate that CPCM improved the temperature regulation capability of HVA, reducing the heating rate and lowering peak temperatures by 0.5–1.5 ℃. CPCM enhanced the elastic response, energy storage capacity, and low-temperature performance of HVA, while reducing temperature sensitivity. Moreover, strain recovery at low strain levels improved. Temperature regulation experiments showed that incorporating 15 % SAS and SM reduced the surface temperature of the steel slag ultra-thin wearing course by 4.78 ℃ and 7.03 ℃, respectively, significantly decreasing the internal temperature gradient of the composite pavement structure. In conclusion, the composite phase change materials SAS and SM exhibited excellent potential for application in steel slag ultra-thin wearing courses, providing effective cooling and delayed thermal response characteristics.