大体积混凝土分层浇筑层间性能及抗裂性能试验研究

Experimental Study on Interlayer Performance and Crack Resistance of Mass Concrete in Layered Placement

恶劣的环境会影响大体积建筑混凝土的层间黏结质量,造成塑性开裂,严重影响结构的安全性和耐久性。文中研究不同处理措施条件下混凝土含水量和抗渗透性,并评估极端天气对混凝土层间性能和抗裂性的影响,以寻找降低大体积混凝土施工风险方法。试验结果表明,在高温环境下,覆盖保温可在一定程度上减少砂浆的失水率,降低抗渗性,且人工凹槽可略微提高混凝土的层间劈裂抗拉强度。对于C1、C2和C3类型的混凝土,层间劈裂抗拉强度分别为0.86、0.58、1.14 MPa,比大体积混凝土(C0)低29%、52%和6%。因此,建议在建筑混凝土层间中使用覆盖保温被,进一步提高建筑混凝土层间黏结质量,以降低施工风险。

Harsh environment will reduce the interlayer bonding quality of mass concrete,resulting in plastic cracking,which seriously affects the safety and durability of the structure.Therefore,this paper studies the water content and permeability resistance of concrete under different treatment measures,and evaluates the impact of extreme weather on the interlayer performance and crack resistance of concrete,in order to find ways to reduce the risk of mass concrete construction.The test results show that,in high temperature environment,covering insulation can reduce the water loss rate of mortar to a certain extent,reduce the permeability resistance,and artificial grooves can slightly increase the interlayer splitting tensile strength of concrete.For C1,C2 and C3 types of concrete,the interlayer splitting tensile strength is 0.86,0.58,1.14 MPa,respectively,which is 29%,52% and 6% lower than that of bulk concrete(C0).Therefore,it is suggested to further improve the bonding quality of building concrete layers and reduce the construction risk by using the covering insulation strategy.