早龄期加载的PVA纤维超高强混凝土徐变性能研究

Creep Behavior of PVA Fiber Ultra-High Strength Concrete Loaded at Early Age

以混凝土强度、聚乙烯醇(PVA)纤维体积分数、加载龄期三个因素作为控制变量,共成型18组混凝土试件,开展了坍落度试验、抗压强度试验、徐变试验,分析不同强度等级、PVA纤维体积分数、加载龄期对混凝土徐变规律的影响。同时,基于ACI209徐变预测模型和试验结果拟合结果,提出了适应早龄期PVA纤维超高强混凝土的徐变预测模型。试验实测曲线与预测模型计算曲线的对比表明,该徐变预测模型能够用于PVA纤维混凝土早龄期徐变随加载时间、纤维体积分数、混凝土强度因子变化的预测。

Three factors of concrete strength,polyvinyl alcohol(PVA)fiber volume content,and loading age are used as control variables.A total of 18 groups of concrete specimens are formed,and slump test,compressive strength test,and creep test are carried out to analyze the influence of different strength grades,PVA fiber volume fraction and loading age on the creep law of concrete.At the same time,based on the ACI209 creep prediction model and the fitting results of the test results,a creep prediction model suitable for the early-age PVA fiber ultra-high strength concrete is proposed.The comparison between the measured curve of the test and the calculated curve of the prediction model shows that the creep prediction model can be used to predict the change of the creep of PVA fiber concrete with loading time,fiber volume fraction and concrete strength factor in the early age.