混凝土降温收缩开裂机理分析

Analysis on the Mechanism of Concrete Shrinkage Cracking Under Cooling

大体积、高强度等级以及炎热季节浇筑的混凝土散热能力差,水化产生的热量在内部积聚,硬化时,内部温度大幅度上升,高温固结将严重影响产物结构的综合性能。降温时,因冷缩和结构约束状态形成拉应力,产生收缩裂缝。目前,在配合比设计、材料选取和施工过程中采取了一些不当措施,增加了温升总量。预防降温收缩开裂,应从让混凝土结构少起热、多散热、降约束以及提高水化产物填充效率,改善界面过渡区,提高水泥浆和骨料变形协调能力入手。

Mass、high-strength and concrete poured in hot season,due to the poor heat dissipation capacity of concrete,the heat generated by hydration accumulates internally,and when hardened,the internal temperature of concrete rises significantly.High temperature consolidation will seriously affect the comprehensive properties of the product structure.When cooling,tensile stress is formed due to cold shrinkage and restraint state,resulting in shrinkage cracks.At present,some improper measures have been taken in the mix design,material selection and construction process,increasing the total temperature rise.To prevent temperature drop shrinkage cracking,we should start with less heat,more heat dissipation,lower constraints,improve the filling efficiency of hydration products,improve the interface transition zone,and improve the deformation coordination ability of cement slurry and aggregate.