侵蚀与荷载耦合作用下砼梁承载力与延性试验

Experimental study on bearing capacity and ductility of reinforced concrete beam in multi-aggressive and loading coupling

摘要:

为探明冻融循环、氯离子侵蚀和硫酸根离子侵蚀与荷载的耦合作用对钢筋混凝土构件承载力和变形的影响,通过室内模拟试验,对持续荷载下侵蚀梁、无荷载下侵蚀梁以及无荷载无侵蚀梁的正截面剩余承载力、延性、破坏机理进行研究.结果表明:荷载与侵蚀环境共同作用加剧了梁的力学性能退化,且持载水平越高,承载力下降越多,延性降低幅度越大;在400次冻融循环过后,预加荷载为70%Fu的混凝土梁的破坏形式由延性破坏转变到脆性破坏.对钢筋混凝土结构承载力和使用寿命进行预测时,应该考虑使用荷载和环境作用的共同影响.横向裂缝对混凝土梁剩余承载力存在影响,要特别关注腐蚀环境中带裂缝工作的高持载梁的耐久性.

Abstract:

A simulative experiment was carried out for researching the influence of freeze-thaw cycles,chloride penetration,sulfate penetration and loading on the bearing capacity and deformation of the reinforcement members.The residual bearing capacity of normal section of bond strength,ductility and failure mechanism of loading-erosion beams,unloading-erosion beams and unloading-non-erosion beams was were discussed.The experimental results show that the coupling effect of loading and aggressive environment accelerate the degradation of mechanical properties and ductility of beams,and the higher the loading,the more the degradation.The failure forms of reinforcement concrete beam changes from ductile failure to brittle failure under the condition of 70%Fu loading.When to predict the bearing capacity and service life of reinforcement structure,the coupling effect of loading and aggressive environment should be concerned.The experimental results also show that the transverse crack is an influential factor for residual bearing capacity,so the durability of beams with transverse cracks and heavy load under the aggressive environment should be paid more attention.