粉煤灰对水工混凝土抗裂性能的影响研究

Study on Effect of Fly Ash on Crack Resistance of Hydraulic Concrete

通过试验研究探讨了0%、10%、40%、70%粉煤灰替代率对水工混凝土早龄期阶段的开裂发展及其耐久性能的影响。结果表明:从0%逐渐增大粉煤灰掺量至70%时混凝土的抗压强度、劈拉强度和弹性模量依次减小70.2%、65.8%、46.1%,从0%逐渐增大至10%、40%、70%时混凝土2d绝热温升依次下降6.8%、52.4%、71.5%,开裂应力与劈拉强度之比为0.60、0.73、0.72、0.62,从0%逐渐增大至40%开裂温度逐渐下降,超过40%以后则开裂温度受影响较小。因此,为有效减少水工混凝土温度裂缝,控制粉煤灰掺量不宜> 40%。

The effects of fly ash replacement rates of 0%,10%,40% and 70% on the cracking development and durability of hydraulic concrete at early age were discussed through experimental research. The results show that: When the fly ash content gradually increases from 0% to 70%,the compressive strength,split tensile strength and elastic modulus of concrete decrease by 70. 2%,65.8% and 46. 1% respectively. When the fly ash content gradually increases from 0% to 10%,40% and70%,the 2d adiabatic temperature rise of concrete decreases by 6. 8%,52. 4% and 71. 5%respectively. The ratio of cracking stress to split tensile strength is 0. 60,0. 73,0. 72,0. 62,and the cracking temperature gradually increases from 0% to 40%,and the cracking temperature is less affected when it exceeds 40%. Therefore,in order to effectively reduce the temperature crack of hydraulic concrete,the fly ash content should not be more than 40%.