Abstract:
Based on the experiment results of drying shrinkage and internal humidity of recycled aggregate thermal insulation concrete (RATIC) with different contents of glazed hollow beads (GHBs), a theoretical model considering the influence of GHBs on the internal curing effect of concrete for the development of internal humidity and drying shrinkage of RATIC was proposed by regression analysis which provided a theoretical basis and experimental basis for revealing the mechanism of the shrinkage and cracking phenomenon of RATIC. Based on the above analysis, the model of the interaction relationship between drying shrinkage, internal humidity, and GHBs contents was established. Studies indicate that the incorporation of GHBs is beneficial to delay the decline of internal humidity resulting in delaying the development of drying shrinkage. Compared with recycled aggregate concrete (RAC), the internal humidity decrease rate of 40GHBs/RAC, 65GHBs/RAC, 90GHBs/RAC and 130GHBs/RAC (GHBs content of 40, 65, 90 and 130 kg/m
3) reduce by 19.57%, 26.09%, 30.43% and 32.61% and the drying shrinkage reduce by 3.13%, 4.69%, 6.56% and 10.31%, respectively. The theoretical model is in good agreement with the experimental results which shows accurate prediction of theoretical model on the development of drying shrinkage and internal humidity of RATIC. There is a good correlation between internal humidity and drying shrinkage and the development of drying shrinkage can be evaluated based on changes in internal humidity.