粗集料对粉煤灰混凝土性能影响

混凝土的架构理论认为混凝土是由砂浆、粗集料和二者之间的界面构成的．试验研究了石灰石、玄武岩、花岗岩和辉绿岩4种不同类型的粗集料对不同粉煤灰掺量混凝土的坍落度、抗压强度、抗折强度和弹性模量的影响，分析了石灰石粗集料对不同粉煤灰掺量混凝土抗冻性的影响．结果表明，粗集料对混凝土的坍落度、抗压强度、抗折强度和弹性模量影响十分显著．粗集料的掺入降低了砂浆基体的扩展度和抗折强度，提高了砂浆基体的抗压强度和弹性模量，此外，粗集料改善了混凝土的抗冻性．随着粉煤灰掺量的增加，混凝土的坍落度提高，但混凝土的力学性能和抗冻性减弱．不同类型的粗集料对混凝土性能的影响相差不大，随着粉煤灰掺量的提高，不同类型粗集料混凝土性能相差也不大．

Influence of coarse aggregate on properties of fly ash concrete

Concrete is composed of mortar matrix, coarse aggregate and their interface zone according to concrete framework theory. Four different types of coarse aggregate (lime stone, basalt, granite, and diabase) with different volume fraction of fly ash are used to check slump, compressive strength, flexural strength and modulus of elasticity, and analyze the influence on frost resistance property of different fly ash volume fraction for lime stone coarse aggregate. The analytical results show that, slump, compressive strength, flexural strength and modulus of elasticity of concrete are affected by coarse aggregate significantly. Flow ability and flexural strength of concrete are decreased, but compressive strength and modulus of elasticity of concrete are increased due to coarse aggregate mixed, furthermore, coarse aggregate improves frost resistance of concrete. Slump is increased, and mechanical properties and frost resistance property of concrete are decreased with fly ash volume fraction increasing. There is little difference for concrete properties using different types of coarse aggregate. The properties of concrete using different types of coarse aggregate are little different with fly ash volume fraction increasing.