粉煤灰掺量对混凝土单轴受拉受压应力-应变曲线的影响

Stress-Strain curve of concrete with different content of fly ash under uniaxial pull and compression

用占胶凝材料总量的0,15%,20%的粉煤灰配置混凝土,并用此种配合比配制的混凝土制成棱柱体试件在材料试验机上测定其单轴受拉和单轴受压的部分应力应变曲线。结果表明:(1)混凝土抗拉强度的增长率>极限拉伸值的增长率>抗拉弹性模量的增长率。(2)粉煤灰掺量从0增加到20%,7d、28d混凝土抗压弹性模量,抗拉强度,抗拉弹性模量都下降,而90d混凝土抗压弹性模量,抗拉强度,抗拉弹性模量都比较接近。(3)粉煤灰掺量为0、15%、20%的上升段(在50%σ_0范围内)应力-应变方程与Hognestad建议的应力-应变方程基本吻合。

Concrete in which coagulation material are replaced by fly ash,the replacing ratio are 0,15%and 20%.Prisms were cast with these mix proportion and the stress-strain curves under uniaxial pull and compression were obtained using tensile-testing machine and compression-testing machine.It can be found that:(1) the growth ratio of tensile is bigger than the growth rate of the maximum tensile srain and the growth rate of the tensile modulus of elasticity,meantime,the growth rate of the maximum tensile srain is bigger than the growth rate of the tensile modulus of elasticity.(2) In early stage(7d,28d),with the increased content of fly ash from 0 to 20%,elastic ratio of compression,tensile strength and the tensile modulus are reduced.While in anaphase(90d) there have little difference.(3) The ascenting(below the 50%σ_0) stress-strain equation of the concrete in which the fly ash replacing ratio are 0,15%and 20%is similar to Hognestad.