再生保温混凝土内部湿度与干燥收缩预测模型

Prediction model of internal humidity and drying shrinkage of recycled aggregate thermal insulation concrete

基于不同玻化微珠(GHBs)掺量下再生保温混凝土(RATIC)的干燥收缩和内部湿度试验结果,考虑GHBs内养护效应对混凝土产生的影响,通过回归分析提出了适用于预测RATIC的干燥收缩和内部湿度发展的理论模型,并对干燥收缩和内部湿度之间的关系进行了分析,并建立RATIC干燥收缩和内部湿度、GHBs掺量间的相互作用关系模型,为揭示RATIC收缩开裂现象的机制提供了理论基础和试验依据。研究表明,GHBs的掺入有利于延缓内部湿度的降低,进而延缓干燥收缩的发展,与再生混凝土(RAC)相比,90天龄期时GHBs掺量40、65、90和130 kg/m^(3)的40GHBs/RAC、65GHBs/RAC、90GHBs/RAC和130GHBs/RAC内部湿度衰减速率降低了19.57%、26.09%、30.43%和32.61%,干燥收缩分别降低了3.13%、4.69%、6.56%和10.31%;理论模型与试验结果的吻合度良好,可通过理论模型来预测RATIC干燥收缩和内部湿度的发展;内部湿度与干燥收缩间存在良好的相关性,可根据内部湿度的变化来评估干燥收缩的发展。

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 of40, 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.