矿物掺合料对自密实混凝土基本性能的影响

Influence of mineral admixtures on properties of self-compacting concrete

为探讨粉煤灰、硅灰掺量对自密实混凝土工作性能和力学性能的影响,对单掺粉煤灰自密实混凝土和复掺粉煤灰硅灰自密实混凝土进行了工作性能测试、抗压强度和抗折强度试验。结果表明:粉煤灰和硅灰的掺入可以提高水泥浆体的流动性,改善自密实混凝土的填充性、间隙通过能力和抗离析性能;3 d龄期时,自密实混凝土的抗压强度和抗折强度随粉煤灰掺量增大均呈逐渐下降的趋势;28 d龄期时,自密实混凝土抗压强度和抗折强度随粉煤灰掺量增大均呈先增后减的趋势;粉煤灰掺量为30%、硅灰掺量为4%时,复掺粉煤灰硅灰自密实混凝土工作性能达到最优,复掺粉煤灰硅灰自密实混凝土28 d龄期抗压强度和抗折强度达到峰值55.60和8.08 MPa,并建立了自密实混凝土抗折强度和抗压强度之间的线性回归关系模型为fcf=8.9507+0.3078fcu。

In order to investigate the influence of fly ash and silica fume contents on the performance and me-chanical properties of self-compacting concrete(SCC),the working performance,compressive strength and flex-ural strength tests of SCC were performed.The results show that the addition of fly ash and silica fume can im-prove the fluidity of cement paste and the working performance of SCC.The 3 days compressive strength and flexural strength of SCC decreased with the increase of fly ash content.The 28 days compressive strength and flexural strength of SCC increased first and then decreased with the increase of fly ash content.When the con-tent of fly ash is 30%and the content of silica fume is 4%,the working performance of SCC with fly ash and sil-ica fume is the best,and the 28 days compressive strength and flexural strength of SCC with fly ash and silica fume reaches the peak value of 55.60 MPa and 8.08 MPa respectively.It is concluded that the addition of fly ash and silica fume can improve the working performance and strength of SCC.The optimal mix ratio of SCC with fly ash and silica fume is proposed.The relationship model between flexural strength and compressive strength of SCC is presented.