外加剂对混凝土蠕变性能影响的试验研究  

Effect of additives on the creep properties of concrete

作　　者：宋梅梅[1] 王传林 吕高 SONG Meimei;WANG Chuanlin;LV Gao(School of Mechanical Engineering,Xi’an Shiyou University,Xi'an 710065,China;School of Civil Engineering,Shantou University,Shantou 515063,China)

机构地区：[1]西安石油大学机械工程学院,陕西西安710065 [2]汕头大学土木工程学院,广东汕头515063

出　　处：《四川建材》2021年第11期1-2,共2页Sichuan Building Materials

基　　金：国家自然科学基金资助项目:多维多点地震激励下油气长输管道的灾变机理及抗震性能研究(51808446);陕西省自然科学基础研究计划一般项目:CSAGRC复合增韧水泥对固井一界面胶结质量的影响机理研究(2021JQ-605)。

摘　　要：研究表明混凝土蠕变是影响结构安全的重要原因之一。本文考察不同外加剂(三聚磷酸钠缓凝剂、玻璃纤维)对混凝土蠕变的影响规律,并分析其微观机理。研究表明混凝土蠕变值随缓凝剂掺量的增大而增加,缓凝剂的加入使得温峰出现时间后移18 h左右,使水泥水化早期诱导期延长。这是由于缓凝剂可与溶液中的Ca^(2+)离子形成络盐,阻碍了Ca(OH)_(2)的结晶析出,降低混凝土内部微观结构的致密性,进而增大混凝土蠕变变形。混凝土蠕变变形随纤维掺量的增大而减小,这是由于玻璃纤维的三维随机分布在一定程度上抑制了混凝土的体积变化,同时纤维内部及纤维-混凝土界面过渡区的高孔隙率使混凝土内部应力场更加连续、均匀,进而降低了混凝土蠕变变形。The research shows that the creep of concrete is one of the important factors affecting the structural safety.In this paper,the effects of different admixtures(sodium tripolyphosphate retarder and glass fiber)on the creep of concrete were investigated,and the micro mechanism was analyzed.The results show that the creep value of concrete increases with the increase of retarder dosage.The addition of retarder makes the time of temperature peak move back about 18h,and prolongs the early induction period of cement hydration.The reason is that the retarder can form complex salt with Ca^(2+)ions in solution,which hinders the crystallization and precipitation of Ca(OH)_(2),reduces the compactness of the internal microstructure of concrete,and then increases the creep deformation of concrete.The results also indicate that creep deformation of concrete decreases with the increase of fiber content.This is because the three-dimensional random distribution of glass fiber inhibits the volume change of concrete to a certain extent.At the same time,the high porosity in the fiber and the transition zone of fiber cement paste interface makes the internal stress field more continuous and uniform,thus reducing the creep deformation of concrete.

关 键 词：混凝土 蠕变 缓凝剂 玻璃纤维 

分 类 号：TU528[建筑科学—建筑技术科学]