利用圆环试验测量混凝土早期收缩徐变

近年来混凝土早期裂缝问题再次引起全球工程界的广泛关注。早期混凝土由于体积变形受到约束而产生的应力是导致混凝土开裂的主要因素。在混凝土应力发展的同时,混凝土徐变也在同时发生着变化。有研究表明,徐变能减少40%-50%的早期应力。圆环试验是用于定性评价混凝土材料抗裂性能的试验方法之一。本文首先分析了圆环试验和单轴拉伸徐变试验的原理,创造性地将圆环试验用于测量早期混凝土的干缩徐变,并设计了试验方案。

The Design of Measureing Shrinkage Creep of Early Age Concrete by the Ring Test

Early age cracking of concrete has re-emerged as an important issue all over the world in recent years.The stress,due to restrained volume change related to thermal deformation and shrinkage in the early age concrete,is the main driving force for the deleterious cracking in the construction stage.During the development of the stress,creep,a very important property of concrete,is always developing.Creep contributes to 40%-50% reduction of the elastically induced stress in the restrained specimen.Ring test,a qualitative test,can provide information to assess the potential for cracking of different concrete.An overview of ring test developed in recent years and mechanism of uniaxial tensile creep test is described in this paper at first.Then,an innovative test equipment based on ring test is outlined.