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1 前言由于水份蒸发和水化产物体积变化等原因,水泥浆凝结硬化时会产生收缩,其收缩率达1%。当其收缩受到边界条件的限制时,其内部便产生拉伸变形。对于强度不高的水泥早期硬化体,由此产生的拉应变常常远超过其极限应变值,因而导致开裂。这种收缩裂缝被认为是混凝土缺乏足够耐久性的重要原因之一。为了控制这种收缩裂缝,人们提出了许多不同的方法,其中,最有效的方法是在混凝土中掺钢纤维或聚丙烯纤维,借助纤维跨缝的锁定作用以阻止裂缝的发展。
1 Introduction Due to water evaporation and hydration products such as volume changes and other reasons, the cement slurry hardening will produce shrinkage, the shrinkage rate of 1%. When its shrinkage is limited by the boundary conditions, its interior will produce tensile deformation. For less hardened concrete early hardened bodies, the resultant tensile strains often far exceed their ultimate strain values, resulting in cracking. This shrinkage crack is considered one of the important reasons for the lack of sufficient durability of concrete. In order to control such shrinkage cracks, many different methods have been proposed. Among them, the most effective method is to mix steel fibers or polypropylene fibers in concrete to prevent the development of cracks by the locking effect of fibers across the seam.