超高性能混凝土的收缩性能及收缩预测模型研究

Study on Shrinkage Performance and Shrinkage Prediction Model of Ultra-High Performance Concrete

试验研究了钢纤维掺量(0、1%、2%)对超高性能混凝土(UHPC)收缩性能的影响,对比分析了5种常用的混凝土收缩预测模型对UHPC的适用性,并基于试验数据建立了适用于UHPC的收缩预测模型。结果表明:掺钢纤维UHPC的收缩应变低于未掺钢纤维的对比组,且钢纤维掺量越大,对UHPC的减缩效果越显著;5种常用的混凝土收缩预测模型对UHPC的适用性较低,其中,ACI 209(92)模型高估了UHPC的40 d后收缩应变,B3模型、CEB-FIP 90模型和中国建科院模型低估了UHPC的收缩应变,GL2000模型对90 d龄期时的收缩应变预测值与试验值相对较为接近;建立的指数函数形式的UHPC收缩应变计算模型的精度较高。

The influence of steel fiber content(0,1%,2%)on the shrinkage performance of ultra-high performance concrete(UHPC)was studied through experiments.The applicability of five commonly used concrete shrinkage prediction models to UHPC was compared and analyzed,and a shrinkage prediction model suitable for UHPC was established based on the test datas.The results show that the shrinkage strain of UHPC mixed with steel fiber is lower than that of comparison group without steel fiber,and the greater the content of steel fiber,the more significant the shrinkage reduction effect of UHPC.The applicability of five commonly used concrete shrinkage prediction models to UHPC is low.ACI 209(92)model overestimates the shrinkage strain of UHPC after 40 days,B3 model,CEB-FIP 90 model and China Academy of Building Research model underestimate the shrinkage strain of UHPC,and GL2000 model predictes the shrinkage strain at the age of 90 days relatively close to the test value.The calculation model of UHPC shrinkage strain in the form of exponential function has high accuracy.