箱型沉管抗裂混凝土的配合比优化设计

Mix proportion optimization design of anti-cracking concrete for box immersed tube

箱型沉管结构复杂、体形庞大,混凝土在硬化过程中受到水化热、收缩、沉降等多重因素的影响导致变形,而变形又受到各种约束的作用产生拉应力。当产生的拉应力超过混凝土的极限抗拉强度时,混凝土就会开裂。箱型沉管混凝土控裂是施工中的难题之一。从影响混凝土开裂的几大因素出发,对混凝土材料本体组分进行优化设计,辅以一定的功能阻裂材料,为工程提供了抗裂性能良好的混凝土配合比。

The box-formed immersed tube is a complicated and large structure.During the hardening of the concrete,the deforming would be caused by multiple factors such as the heat of hydration,shrinkage and settlement.The tensile stress would arise from the deformation as various restrains.The concrete would crack,if the tensile stress is more than the ultimate tensile strength of concrete.The crack control of the box-formed immersed tube is a big problem on the execution site.This paper carried out an optimal design to concrete ingredients assisted with certain functional anticracking materials and provided concrete with a good anti-cracking ability.