预制T梁早期水化热温度效应及梁端开裂机理  

Effect of hydration heat temperature and cracking mechanism of beam end in early stage of T⁃beam

作　　者：惠迎新[1,2,3] 孙晓荣 王红雨 高晨[1] HUI Ying-xin;SUN Xiao-rong;WANG Hong-yu;GAO Chen;无(School of Civil and Hydraulic Engineering,Ningxia University,Yinchuan 750021,China;Ningxia Communications Construction Co.,Ltd.,Yinchuan 750002,China;Ningxia Engineering Technology Research Center for Road Maintenance,Yinchuan 750002,China)

机构地区：[1]宁夏大学土木与水利工程学院,银川750021 [2]宁夏交通建设股份有限公司,银川750002 [3]宁夏道路养护工程技术研究中心,银川750001

出　　处：《吉林大学学报（工学版）》2021年第5期1734-1741,共8页Journal of Jilin University:Engineering and Technology Edition

基　　金：宁夏回族自治区重点研发计划项目(2020BFG02005).

摘　　要：为避免预制混凝土T梁在施工养护期间产生较高的水化热而导致梁端出现早期竖向裂缝,以一座40 m预应力混凝土T梁为研究对象,对其浇筑过程水化热发展及早龄期力学性能进行监测与测试,并基于实测结果建立考虑梁段早期时变的精细化有限元模型,研究浇筑过程水化热温度场演变特征、梁端应力分布规律。结果表明:40 m跨预制T梁在混凝土浇筑初期,靠近梁端位置因水化过程中的温度迅速聚集而具有较高的开裂风险,且在距梁端2~4 m区域的腹板靠近翼缘板位置易贯通。建议控制入模温度在20℃以内并采用优化配合比的方法,减少水泥用量或采用低水化热水泥,以达到降低水化热和防止裂缝产生的目的。In order to avoid high hydration heat of precast concrete T beam during construction and maintenance,early vertical cracks appear at the beam end.Taking a 40-meter prestressed concrete Tbeam as the research object,the mechanical properties of the concrete t-beam during the pouring process were monitored and tested.According to the measured results,a refined finite element model considering the early time-varying of the beam segment was established.And based on the above model,the evolution characteristics of hydration heat temperature field and the stress distribution law at the end of the beam during pouring process were studied.The results show that in the initial stage of concrete pouring of the 40-meter-span precast T-beam,the position near the beam end has a higher risk of cracking due to the rapid accumulation of temperature during the hydration process.In the area 2m~4m away from the beam end,the cracks are easy to penetrate through the web near the flange plate.It is recommended to control the mold-in temperature within 20℃,and adopt the method of optimizing the mixing ratio,reduce the amount of cement or use low-heat-of-hydration cement to reduce the heat of hydration and prevent cracking.

关 键 词：预应力混凝土T型梁 梁端裂缝 水化热 温度场 应力场 有限元法 

分 类 号：U441[建筑科学—桥梁与隧道工程]