冻融环境下约束混凝土应力-应变全曲线试验研究  

STRESS-STRAIN RELATIONSHIP OF STIRRUP-CONFINED CONCRETE SUBJECTED TO FREEZE-THAW CYCLES

作　　者：段安[1] 钱稼茹[1] 

机构地区：[1]清华大学结构工程与振动教育部重点实验室,北京100084

出　　处：《岩石力学与工程学报》2010年第A01期3015-3022,共8页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金资助重点项目(50538060)

摘　　要：为研究冻融环境下箍筋约束混凝土应力-应变关系,按照GBJ82-85规定的快速冻融试验方法,对2批共54个尺寸为150mm×150mm×450mm、配箍特征值分别为0.317和0.145的混凝土棱柱体试件进行冻融循环;对其中46个试件进行轴心抗压破坏试验,得到试验应力-应变全过程曲线。试验发现:随着冻融次数的增加,约束混凝土的受压应力-应变全曲线渐趋扁平,峰值应力呈线性降低,峰值应变增加。冻融循环次数相同时,混凝土强度高的试件,其峰值应力降低的程度和峰值应变增大的程度小于混凝土强度低的试件。另外,在混凝土强度较低的情况下,冻融将导致钢筋与混凝土之间的黏结界面发生损伤,使得箍筋约束效应减弱。通过回归试验结果,提出试验受冻融循环作用箍筋约束混凝土的应力-应变全曲线方程及确定其参数的公式,该公式可用于寒冷地区受冻融作用的钢筋混凝土结构构件的非线性分析。In order to investigate the stress-strain relationship for stirrup-confined conorete after freez-thaw cycles, two series of concrete specimens（150 mm×150 mm×450mm） with stirrup characteristic values of 0.317 and 0.145 respectively were exposed to rapid freeze-thaw cycles in water according to GBJ82- 85. The axial compressive loading tests were carried out to obtain the complete stress-strain curves of confined concrete. Test results of 46 specimens show that, with the increase of freeze-thaw cycle number, the complete stress-strain curve becomes more flat, the peak stress decreases and the peak strain increases; with the same number of freez-thaw, the reduction of the peak stress and the increase of the peak strain are more serious for lower strength concrete. Moreover, damage appears at the bonding interface between stirrups and concrete due to freeze-thaw action, and the confining effect of the stirrups is weakened for lower strength concrete. Based on the test results, theoretical complete stress-strain curve equations for confined concrete subjected to freeze-thaw cycles are established. The equations could be used for nonlinear analysis of reinforced concrete structural elements experienced to freeze-thaw cycles in cold regions.

关 键 词：建筑材料 约束混凝土 冻融循环 应力-应变全曲线 

分 类 号：TU502.6[建筑科学—建筑技术科学]