Reflective cracking from thermal loading in asphalt–concrete composite pavements Available to Purchase

Composite pavements made from a hot-mix asphalt layer over a Portland cement concrete slab typically suffer from reflective cracking. Due to repetitive slab joint movements, concentrated stresses occur under the asphalt layer and propagate towards the surface. Recently, top-down reflective cracking has been observed in the field on pavements with no traffic. Previous studies have indicated that asphalt ageing may be the main cause of this problem. However, top-down reflection cracks may occur when upward curling of the concrete slab base creates a concentrated stress on top of the asphalt. Other design parameters such as thickness, stiffness or joint spacing may also influence this cracking behaviour. In the study reported in this paper, reflective crack propagation under thermal loading was investigated to identify potential factors that cause top-down reflection cracks. The results showed that top-down reflection cracks appeared only in composite pavements where the slab base had a low elastic modulus.