C80高性能混凝土力学性能的粉煤灰效应

Effect of fly ash on mechanical property of C80 high performance concrete

在前期C80高性能混凝土试验研究确定的优化配合比基础上,以粉煤灰取代率和龄期为因素,应用具有位移传感器的SANS压力试验机,参照普通混凝土力学性能试验方法标准GB/T 50081—2002,进行了粉煤灰对C80高性能混凝土力学性能的作用效应试验研究。结果表明:掺适量的粉煤灰能够显著提高混凝土的抗拉强度和拉压比,就劈裂抗拉强度和拉压比而言,粉煤灰取代率存在一个最佳值;掺粉煤灰使混凝土的弹性模量降低,延性提高;掺适量粉煤灰的混凝土,其强度、拉压比和弹性模量均随龄期的增大而增大。混凝土中水化硅酸钙胶体的增多和Ca(OH)2晶体的减少是粉煤灰混凝土的抗拉强度和拉压比增大,弹性模量降低的主要原因。该研究为混凝土结构构件的抗裂设计和变形设计提供了理论支撑。

On the basis of the optimal mixture ratio of C80 high performance concrete determined by test in the early days,with the fly ash replacement rate and age as the factors,application of SANS pressure testing machine with displacement sensor,according to the GB/T 50081—2002 Standard for test methods of mechanical properties of ordinary concrete,the effect of fly ash on the mechanical property of C80 high performance concrete was studied. The results showed that the right amount of fly ash can significantly improve the tensile strength,tension and compression ratio of concrete,in terms of splitting tensile strength,tension and compression ratio,fly ash replacement ratio is a best value.Mixing fly ash can decrease the elastic modulus,improve ductility of concrete.Concrete with right amount of fly ash,its strength,tension and compression ratio,and elastic modulus increase with the increase of the age.About fly ash concrete,hydration calcium silicate colloid increasing and Ca（OH）2crystals decreasing was the main reason for the tensile strength,tension and compression ratio increasing,elastic modulus decreasing. The theoretical support is provided for the design of anti-cracking and deformation in the concrete structure.