再生混凝土导热系数试验与分析

采用单位体积用水量、水灰比、再生粗骨料取代率和再生细骨料取代率这4个影响因素设计正交试验,研究这些因素对再生混凝土导热系数和密度的影响;同时定义骨料影响系数C,分析了再生混凝土导热系数变化的内在机理,并基于普通混凝土导热系数的计算公式,提出了修正的再生混凝土导热系数计算公式.结果表明:4个影响因素中,再生粗骨料取代率对再生混凝土导热系数影响最大;再生混凝土导热系数与C值间存在显著的线性关系;修正的再生混凝土导热系数计算公式的计算结果与试验结果吻合较好,便于实际工程应用.

Experimental Study on Thermal Conductivity of Recycled Concrete

Thermal conductivity is an important design parameter when recycled concrete is used for wall material. Considering the effect of four factors, including unit water consumption, water cement ratio, recycled coarse aggregate replacement ratio and recycled fine aggregate replacement ratio, an orthogonal test was conducted to study thermal conductivity and density of recycled concrete. By defining an aggregate impact factor C, the internal mechanism of thermal conductivity change was analyzed. Based on the calculation formula for the thermal conductivity of normal concrete, a modified formula for recycled concrete was proposed. The results show that the replacement ratio of recycled coarse aggregate in four factors has the greatest influence on thermal conductivity of recycled concrete. There is a significant linear relationship between thermal conductivity of recycled concrete and the value C. Calculated values from modified formula for thermal conductivity of recycled concrete agree basically with experimental values. The modified formula could be applied in the practical engineering.