锈裂混凝土裂缝形态的试验研究

TEST STUDY OF CONCRETE COVER CRACK FORM BY CORRODED REBAR

钢筋混凝土结构中 ,钢筋锈蚀产生体积膨胀 ,对外围混凝土产生径向压应力 ,导致混凝土开裂。在锈蚀混凝土构件的评估中 ,裂缝的分布形态和裂缝宽度是最明显和最直观的评估依据。试验室中 ,通过对混凝土试件的预留孔进行机械扩孔 ,模拟钢筋锈蚀膨胀引起混凝土开裂的全过程。机械扩孔试验用膨胀螺栓和水压机对 94个试件进行了不同条件下的扩孔 ,来模拟钢筋锈蚀在构件表面引起的应力分布及裂缝分布形态。分析混凝土保护层开裂趋势、裂缝扩展方式、裂缝分布形态与混凝土强度、钢筋直径、保护层厚度、钢筋位置、浇筑方式之间的关系 ,最后用有限元对一典型试件进行数值模拟计算。

In reinforced concrete structure,the reinforcement corrodes and the volume of these corroded products expand to create pressure to the surround concrete of reinforcement.To the assessment of the corroded concrete structure,the most obvious and direct assessment methods are the crack form and crack width.In the lab,concrete cracking process, caused by the rebar′s corrosion,is simulated by enlarging the pre-located hole on the test pieces.Bulging bolt and water press are used to simulate the stress distribution and crack forms on the members′surface.Cracking trend of cover concrete,crack developing and crack forms are analyzed on condition of these factors,such as concrete strength,reinforcement diameter,cover depth,reinforcement position,and casting mode.In the end,the finite element method is used to simulate the stress field of a typical test piece.