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【问】我队台座生产预应力钢弦混凝土多孔板,当整条生产线混凝土浇捣后不到一个星期,常有一些板出现横向裂缝,不知是什么原因,请帮助分析和提出解决办法。(浙江省余姚县沿江建筑工程队傅丁芳)【答】预应力多孔板早期出现横向裂缝,一般有以下几种情况:1.混凝土养护不好,表面出现干缩裂缝;2.长线台座水泥底模表面粗糙不平,隔离剂效果不好,板与底模粘结,当底模受外界气温变化热胀冷缩时将板拉裂;3.板跨过水泥底模伸缩缝;4.板本身温度与收缩变形,放
[Q] In the production of prestressed steel string concrete perforated plates in our team’s pedestal, when the entire production line is concrete poured, there are often some plates with transverse cracks. I do not know why. Please help analyze and propose solutions. (Fu Dingfang, Yanjiang Yanjiang Construction Engineering Team) [Answer] The early appearance of transverse cracks in the prestressed porous plate, there are generally the following situations: 1. Concrete curing is not good, the surface appears dry shrinkage cracks; 2. Long line pedestal cement bottom mold The surface roughness is rough, the effect of the separating agent is not good, the board is bonded to the bottom mold, the board is cracked when the bottom mold is subject to thermal expansion and contraction due to changes in the outside temperature; 3. The board crosses the cement bottom mold expansion joint; 4. The board itself temperature With shrinkage deformation, put