超高韧性水泥基复合材料加固钢筋混凝土梁弯曲控裂试验研究  

Experimental study on flexural characteristics of RC beams strengthened with post-poured ultra high toughness cementitious composites

作　　者：徐世烺[1] 王楠 尹世平[3] 

机构地区：[1]浙江大学建筑工程学院,浙江杭州310058 [2]大连市建筑科学研究设计院股份有限公司,辽宁大连116021 [3]中国矿业大学力学与建筑工程学院,江苏徐州221116

出　　处：《建筑结构学报》2011年第9期115-122,共8页Journal of Building Structures

基　　金：国家自然科学基金重点项目(50438010);南水北调工程建设重大关键技术研究及应用(JGZXJJ2006-13)

摘　　要：按照正常配筋浇筑了9根钢筋混凝土梁,在部分混凝土梁受拉面上浇筑复合材料进行局部加固,其中1根为未加固的混凝土对比梁,5根为后浇超高韧性水泥基复合材料(UHTCC)加固梁,3根为后浇UHTCC层配置纵向受力钢筋的加固梁。通过三分点受弯试验,对后浇UHTCC加固梁的破坏形态、梁体变形、裂缝发展、开裂荷载以及承载力等进行研究,并与未加固混凝土对比梁进行比较。结果表明,该加固方法能够有效提高梁的承载力和初始截面刚度,加固后仍有较好的延性,加固层限制了上层混凝土宏观裂缝的发展并实现将其无害化分散,推迟梁底有害裂缝的出现,提高了构件的正常使用极限荷载,具有良好的加固效果。试验还发现,不同的加固长度和后浇层厚度导致了不同的破坏形式;若构件在强度和刚度上有较高要求,可选择在后浇UHTCC层中布置纵筋;布置纵筋后,加固层端部集中应力随之增大,植筋可改善UHTCC和既有混凝土界面的粘结受力状态。Nine concrete beams were cast and tested based on a normal steel reinforcement configuration,which included one specimen for comparison without strengthening,five specimens strengthened with post-poured UHTCC and three specimens strengthened with reinforced UHTCC.UHTCC material was poured on local bending face of the existing reinforced concrete beams to form the strengthened specimens.The failure mode,deformation,crack development,cracking load and ultimate load of the beams were studied under four-point bending tests and compared with those of contrast beam.The results indicate that the load-bearing capacity and initial section stiffness of the beams can be increased effectively by using the strengthening method.Introducing UHTCC material into strengthening not only enables the composite beams to sustain the loading at a large deflection level without failure,but also disperses the cracks in upper concrete into multiple fine cracks to delay the appearance of harmful cracks on the bending face.In addition,different lengths and thicknesses of the post-poured layer lead to different failure modes.Reinforced UHTCC can satisfy higher strength and stiffness requirements.However,end stress of the strengthened beams increases accordingly with the increase of the strengthening layer stiffness.Planting reinforcing bar is an effective method for improving the bonding of the interface between the post-poured UHTCC and the existing concrete.

关 键 词：钢筋混凝土梁加固 超高韧性水泥基复合材料 静力试验 弯曲性能 控裂 

分 类 号：TU375.102[建筑科学—结构工程] TU317.1