Experimental research on the performance of the thermal-reflective coatings with liquid silicone rubber for pavement applications

Abstract

Abstract The thermal-reflective coating technology can effectively realize the active cooling of asphalt pavement, thus delaying the occurrence of pavement rutting. Although solid fillers are usually used to absorb light and weaken light dazzle in traditional thermal-reflective coatings, this method makes the filler component complicated and the coatings more viscous and increases the difficulty of painting the coating material on the pavement surface. On account of all the aforementioned factors, this experimental study aims to effectively improve the performance of the thermal-reflective coating with liquid silicone rubber addition in which epoxy resin is the base material and rutile titanium dioxide is the pigment filler for the coating film. Through lab experiments, the effects of the proper liquid silicone rubber dosage on the glossiness, cooling performance, and hardness of the thermal-reflective coating are studied and analyzed. The experimental results show that the liquid silicone is very effective for coating toughness improvement. The thermal-reflective coating, when the liquid silicone rubber dosage changes from 10 to 14 wt%, exhibits a matt state, and its glossiness can be controlled below 30 GU, which meets the safety and antiglare requirements of traffic vehicles. It demonstrates that liquid silicone rubber can influence the viscosity of the thermal-reflective coatings, and when the liquid silicone dosage reaches 16 wt%, the viscosity of the coating increases by 7.26 wt% less than that of the solid matting filler. Liquid silicone rubber can also influence the cooling effect of the thermal-reflective coatings, with the liquid silicone rubber dosage of 16 wt%, the asphalt pavement temperature can reduce 0.5°C. Besides, liquid silicone rubber reduces the hardness of the coatings, the coating hardness is 6H when the liquid silicone rubber dosage is 0–10 wt%, and the hardness of the coating reduces to 5H when liquid silicone dosage is from 12 to 16 wt%, which meets the actual requirements. Therefore, this article recommends a 12 wt% dosage of the liquid silicone rubber to be used as a matting filler for the thermal-reflective coatings.