水泥基材料塑性阶段变形特性研究

Deformation properties of cement-based materials during plastic stage

利用波纹管研究了水泥基材料塑性阶段的变形行为,同时测试基体的毛细管负压发展规律,分析了变形特性与凝结行为。结果表明:非泌水状态下,浆体的塑性阶段收缩变形呈阶段性发展,存在特征拐点或区域,与毛细管负压发展具有强对应关系。低水灰比浆体的特征拐点更为明显,高水灰比浆体则存在特征区域,据此进行的凝结时间判定与维卡仪测试结果相近。泌水会影响浆体塑性阶段的变形历程,导致变形曲线特征不明显。

Deformation behavior measured by corrugated tube and development of capillary pressure were adopted to describe the defor- mation properties of cement-based materials during plastic stage,the relation between deformation properties and setting time was dis- cussed.Results indicate that plastic shrinkage of cement paste without bleeding is in phased development, the feature turning points and re- gion are observed preferential for cement paste with low and high water cement ratio, respectively, which are well correspondent to the de- velopment of capillary pressure.According to the features, setting time can be determined and the results are in a good agreement with the results obtained by vicat.The process of plastic deformation can be effect significantly by bleeding water, which resulting in indistinct fea- ture of deformation.