WFS-FA-EPS 填料导热系数试验研究

Abstract

采用ISOMET 热特性分析仪对废铸砂（WFS）、粉煤灰（FA）、聚苯乙烯（EPS）颗粒、水泥（可选）与水 按一定质量比例混合制成的抗冻胀、低导热性、轻质填料进行了导热系数测定，探讨了不同状态下（冻结与否）导热 系数与水泥、粉煤灰、EPS 颗粒掺入比、含水率以及龄期的关系，并与常规岩土材料进行对比，进行了变量权重的正 交分析，建立导热系数与不同组分含量关系的预测公式。试验结果表明，单因素变化时，EPS 颗粒含量、粉煤灰含量、 水泥含量的增加会不同程度地降低导热系数，有助于隔热与降低冻结深度；干密度和含水率的降低会减小导热系数； 龄期的增加会增加导热系数；主要变量因素降低填料导热系数的权重由大到小顺序为EPS 颗粒、粉煤灰和含水率；材 料的导热系数随水料比w/(10EPS+FA)的增加而增加；试验调查的填料导热系数在0.5～1.0 W/m⋅K 范围，低于常见岩土 材料的导热系数（1.0~2.0 W/m⋅K）。= The thermal conductivity is a critical parameter of infrastructure materials, which are used as frost-resistant fills in cold regions. The parameter is mainly determined by the material composition. A frost-resistant fill, composed of waste foundry sand (WFS), fly ash (FA), expandable polystyrene (EPS), Portland cement and water, is proposed. ISOMET apparatus is used to measure the thermal conductivity of the fills, in particular, the effect of mixing ratios on the thermal conductivity of WFS-FA-EPS fills. The test results show that the increase of EPS beads, FA or cement results in the decrease of thermal conductivity of the fills. The increase in dry density or moisture contents enhances the thermal conductivity. The components in descending order affecting the thermal conductivity are EPS, FA and water. The increase of water-EPS/FA mass ratio increases the thermal conductivity of materials. The thermal conductivity of investigated specimens ranges between 0.5～1.0 W/m×K, favorably less than that of general geomaterials, e.g., 1.0～2.0 W/m×K.