Effect of degree of ceramsite prewetting on the cracking behaviour of LWAC

摘要

The water absorption and desorption process, the interfacial transition zone (ITZ) and the cracking behaviour of lightweight aggregate concrete (LWAC) were obtained by a U-tube micro-pressure measurement device, a scanning electron microscopy test and a new restrained-shrinkage ring device, respectively. The study reveals that, with the increase in degree of ceramsite prewetting, the water absorption ability declines, while the water desorption ability improves for ceramsites embedded in the LWAC, and the ITZ of the LWAC becomes compact. The cracking ages of the LWAC rings with ceramsites pre wetted for 0 h, 1 h and 24 h are respectively 10·7 days, 15·3 days and 25 days. At the age of 28 days, the crack width of LWAC rings decreases with the increase in degree of ceramsite prewetting. Also, with the increase in degree of ceramsite prewetting, the restrained-shrinkage cracking behaviour of the LWAC rings improves. The research results provide clues for the preparation of the LWAC with better crack-resistant behaviour.