摘要
以某工业项目楼层板为研究对象,针对超长混凝土结构设计后张法预应力施工,同时在混凝土配合比中增加镁质膨胀剂,研究超长混凝土结构内部的应力-应变规律,以及后张法对预防超长混凝土楼板开裂的作用规律,进行了混凝土材料膨胀试验、强度对比和应力-应变监测。结果表明:镁质膨胀剂能够改善混凝土抗裂性,减缓应变,对混凝土防裂性有效;在后张法预应力施工后,混凝土结构内部应变量增大,应力由拉应力转变为压应力,对预防混凝土结构内部裂缝有效;预测判断混凝土内部受拉极限值、超长混凝土结构张拉起始点和张拉力等因素对混凝土早期内部受力状态十分重要。
Taking a certain industrial project floor slab as the research object,the post tensioning method is designed for the construction of ultra long concrete structures.At the same time,magnesium based expansion agents are added to the concrete mix proportion to study the stress-strain law inside the ultra long concrete structure,as well as the role of post tensioning method in preventing cracking of ultra long concrete floor slabs,through the expansion test of concrete materials,strength comparison,stress and strain monitoring.The research results show that magnesium expansion agent can improve the crack resistance of concrete,slow down the strain,and is effective for the crack resistance of concrete;after post tensioning construction,the internal stress of concrete structure increases,and the stress changes from tensile stress to compressive stress;effective for preventing internal cracks of concrete structures,it is very important to predict and judge the internal tensile limit value of concrete,the starting point of super long concrete structure tensioning,and the tensioning force for the early internal stress state of concrete.
出处
《混凝土世界》
2023年第5期62-66,共5页
China Concrete
基金
2022年河北省建设科技研究项目指导性计划(2022-2158)
2022年河南省住房城乡建设科技计划项目(HNJS-2022-K24)。
关键词
混凝土
预应力
镁类膨胀剂
后张法
裂缝控制
Concrete
prestress
magnesium expansion agent
post tensioning method
crack control
