无沙混凝土垫层配合比及力学性能试验研究

Study of Test on Mixed Proportions Design and Mechanical Properties of No Fines Concrete Cushion Layer

防渗体土工膜下垫层应具有较高的强度、较小的弹性模量、较好的透水性。在土工膜防渗结构中,将无沙混凝土作为垫层,并进行了无沙混凝土垫层配合比优化设计及力学性能研究。结果表明:无沙混凝土抗压强度随着计算孔隙率的增大而呈减弱趋势;提高水泥改性剂替代水的比例可以增强无沙混凝土的抗压强度,但若水泥改性剂替代水的比例过大则抗压强度呈减弱趋势;无沙混凝土抗折强度很小。根据试验结果得出了中低堆石坝土工膜防渗垫层的最佳配合比。

The cushion layer in impermeable geo-membrane structure should possess high strength, low elastic modulus and good permeability. In that structure, no fines concrete was used as geo-membrane cushion layer, and its optimum mixed proportions design and mechanical properties were investigated experimentally. The results show that ： the compressive strength decreases with the increase of computing porosity ; to raise instead water ratio of cement modifier can strengthen compressive strength, but too large ratio will cause decrease trend of compressive ; the tensile strength of no fines concrete is also low. According to the test study, it concludes the optimum mixed proportions.