超大体积混凝土温度裂缝产生机理分析与抗裂控制新对策

介绍了超大体积混凝土的概念;阐述了超大体积混凝土温度裂缝产生的两个必要条件是温差和约束;指出超大体积混凝土在水泥水化升温的初期,混凝土容易出现内高外低的温差,在内约束作用下,形成表面裂缝;在超大体积混凝土降温阶段,由于混凝土的收缩,在外约束作用下,容易导致贯穿裂缝.贯穿裂缝会严重影响结构的性能,它会破坏结构的整体性、耐久性等.根据"抗放兼施"的原则,提出了两种实用的抗裂新对策:运用"复合式的超大体积贫混凝土"和运用"有弹性的滑动式垫层",并介绍这两种对策在工程中的具体做法.这两种方法对超大体积混凝土抗裂问题具有一定的指导意义.

Mechanism analysis of temperature crack appear of super mass concrete and new methods of anti-rack

This paper introduces the concept of super mass concrete;elaborates the two main essential requirements,temperature difference and constraints,of the temperature crack of super mass concrete;points out that at the early stage of hydration reaction of super mass concrete,the temperature difference is easy to come out.Under inner constraint,surface crack comes out;During the cooling stage of super mass concrete,the shrinkage of concrete under external restraints is easier to cause the appearance of transverse cracks,which will severely affect the properties of structure and destroy the integrity and durability of structure and so on.Based on the principle of anti-rack and removal of constraints,the paper proposes two new practicable countermeasures:compound super mass lean concrete and elastic-sliding bedding cushion and also introduces the specific methods of them in the real projects.These two measures have certain guide meaning of cracking resistance problems of super mass concrete.