Zang Xuhang, Zhu Pinghua, Chen Chunhong, Yan Xiancui, Wang Xinjie
Changzhou City Key Laboratory of Building Energy-Saving Technology, Department of Civil Engineering, Changzhou University, Changzhou 213164, China.
Materials (Basel). 2021 Sep 26;14(19):5581. doi: 10.3390/ma14195581.
In this study, the shrinkage performance of recycled aggregate thermal insulation concrete (RATIC) with added glazed hollow beads (GHB) was investigated and a time-dependent shrinkage model was proposed. Two types of recycled fine aggregate (RFA) were used to replace natural fine aggregate in RATIC: RFA from waste concrete (RFA1) and waste clay brick (RFA2). Besides, the mechanical properties and thermal insulation performance of RATIC were also studied. Results showed that the pozzolanic reaction caused by RFA2 effectively improved the mechanical properties of RATIC; 75% was the optimal replacement ratio of RATIC prepared by RFA2. Added RFA decreased the thermal conductivity of thermal insulation concrete (TIC). The total shrinkage strain of RATIC increased with the increase of the replacement ratio of RFA. The 150d total shrinkage of RATIC prepared by RFA1 was 1.46 times that of TIC and the 150d total shrinkage of RATIC prepared by RFA2 was 1.23 times. The addition of GHBs led to the increase of early total shrinkage strain of concrete. Under the combined action of the higher elastic modulus of RFA2 and the pozzolanic components contained in RFA2, the total shrinkage strain of RATIC prepared by RFA2 with the same replacement ratio was smaller than that of RATIC prepared by RFA1. For example, the final total shrinkage strain of RATIC prepared by RFA2 at 100% replacement ratio was about 18.6% less than that of RATIC prepared by RFA1. A time-dependent shrinkage model considering the influence of the elastic modulus of RFA and the addition of GHB on the total shrinkage of RATIC was proposed and validated by the experimental results.
本研究对添加玻化微珠（GHB）的再生骨料保温混凝土（RATIC）的收缩性能进行了研究，并提出了一个时变收缩模型。使用两种类型的再生细骨料（RFA）来替代RATIC中的天然细骨料：废弃混凝土中的RFA（RFA1）和废弃粘土砖中的RFA（RFA2）。此外，还研究了RATIC的力学性能和保温性能。结果表明，RFA2引起的火山灰反应有效改善了RATIC的力学性能；75%是RFA2制备RATIC的最佳替代率。添加RFA降低了保温混凝土（TIC）的导热系数。RATIC的总收缩应变随RFA替代率的增加而增大。RFA1制备的RATIC的150d总收缩量是TIC的1.46倍，RFA2制备的RATIC的150d总收缩量是TIC的1.23倍。添加GHB导致混凝土早期总收缩应变增大。在RFA2较高弹性模量和RFA2所含火山灰成分的共同作用下，相同替代率下RFA2制备的RATIC的总收缩应变小于RFA1制备的RATIC。例如，100%替代率下RFA2制备的RATIC的最终总收缩应变比RFA1制备的RATIC小约18.6%。提出了一个考虑RFA弹性模量和GHB添加量对RATIC总收缩影响的时变收缩模型，并通过实验结果进行了验证。
