硅灰掺量对预制混凝土界面黏结性能影响研究

Study on the effect of silica fume admixture on the interfacial adhesion performance of precast concrete

为提高砂浆垫层与预制混凝土墩柱、承台界面间的黏结性能,在连接处涂刷一层界面剂,采用水泥净浆为基准,以不同硅灰掺量为变量,研究硅灰掺量对预制混凝土界面黏结性能的影响,通过实验分别测试了抗折强度、抗压强度、劈拉强度及剪切强度。结果表明,从力学性能上看,同一龄期下,抗折及抗压强度均随着硅灰掺量的增加呈现先提升后下降的趋势,硅灰掺量为8%时的抗折与抗压强度值最大,分别为9.5,63.6 MPa,表现为力学性能最好;从黏结性能上看,劈拉及剪切强度均随着硅灰掺量的增加出现先增加后减小的现象,掺量为8%时,28 d强度值分别为1.7 MPa和1.65 MPa,黏结性能最优,28 d强度增长率较7 d分别提高了40%和65%。综合分析力学性能和黏结性能,得出硅灰掺量为8%时,界面黏结效果最优。

In order to improve the bonding performance between the mortar bedding layer and the interface of precast concrete piers and bearings,a layer of interface agent was painted at the joint,and the effect of silica fume admixture on the bonding performance of the interface of precast concrete was studied with different silica fume admixtures as the reference,and the flexural strength,compressive strength,tensile strength and shear strength were tested respectively.The results showed that the flexural and compressive strengths increased and then decreased with the increase of silica fume dosage at the same age,and the flexural and compressive strengths were the highest at 8% of silica fume dosage,which were 9.5 MPa and 63.6 MPa,respectively.The 28 d strength values were 1.7 MPa and 1.65 MPa at 8%,which showed the best adhesion performance,and the 28 d strength growth rate increased by 40% and 65% respectively compared with 7 d.The mechanical properties and adhesion performance were analyzed comprehensively,and it was concluded that the interfacial adhesion effect was the best at 8% of silica fume.