Spray water cooling of newly laid asphalt pavement for rapid opening to traffic

Freshly paved asphalt must be sufficiently warm before it can be trafficked to prevent premature failure. In countries with high air ambient temperature, the newly laid asphalt temperatures reduce slowly; thus, it requires lengthy periods to reach the opening-to-traffic asphalt temperature. Some contractors practice spraying water onto the freshly paved asphalt to accelerate the cooling time, so the new sections can be quickly opened to traffic. However, no particular research has been performed regarding this practice. This study aims to investigate the effectiveness of spray water cooling and examine the potential detrimental effects on the asphalt material properties. For this purpose, laboratory temperature measurements and heat transfer analyses of natural cooling and water spray cooling were performed. In addition, Cantabro and indirect tensile strength (IDT) testing were carried outto investigate the possible drawbacks of water. The results indicate the water spray application onto newly laid asphalt pavement does not necessarily adversely affect the asphalt durability (resistance to cohesion loss) and or the moisture damage of asphalt pavement. However, it is likely to be of limited value in accelerating the cooling of overlays, except when they are relatively thin.