高性能地聚物混凝土早期收缩特性

Early shrinkage characteristics of high performance geopolymer concrete

为研究高性能地聚物混凝土的早期收缩性能,进行系列试验研究与分析。研究表明:在试验掺量变量范围内,硅灰掺量及水玻璃模数对高性能地聚物混凝土早期干燥收缩影响一致,均先减小后增大;硅灰掺量及钢纤维掺量对高性能地聚物混凝土早期自收缩影响一致,均先增大后减小,之后再增大。在水玻璃模数范围内,水玻璃模数对高性能地聚物混凝土早期自收缩均为负面影响,增大水玻璃模数,高性能地聚物混凝土早期自收缩均依次增大。在试验钢纤维掺量范围内,钢纤维掺量对高性能地聚物混凝土早期干燥收缩均为正面影响,增加钢纤维掺量,高性能地聚物混凝土早期干燥收缩均依次降低。高性能地聚物混凝土试件早期干燥收缩均在1411×10^(-6)~4387×10^(-6)之间,早期自收缩均在856×10^(-6)~1188×10^(-6)之间。随龄期增长,高性能地聚物混凝土干燥收缩初期增长较快,自收缩先略微减小后快速增长,之后均逐渐趋于平缓,并可将早期收缩曲线分为3个阶段(快速增长段、缓慢增长段和稳定段)。基于早期干燥收缩实测值,验证了GL2000模型对高性能地聚物混凝土早期干燥收缩曲线的适用性。

In order to study the early shrinkage performance of high performance geopolymer concrete,a series of experimental research and analysis were carried out.The results show that the influence of silica fume content and water glass modulus on the early drying shrinkage of high performance geopolymer concrete is consistent within the range of test content,which decreases first and then increases.The influence of silica fume content and steel fiber content on the early autogenous shrinkage of high performance geopolymer concrete is consistent,which increases first and then decreases,and then increases.In the range of water glass modulus,the water glass modulus has a negative effect on the early autogenous shrinkage of high performance geopolymer concrete.Increasing the water glass modulus,the early autogenous shrinkage of high performance geopolymer concrete increases in turn.In the range of steel fiber content in the test,the steel fiber content has a positive effect on the early drying shrinkage of high performance geopolymer concrete.With the increase of steel fiber content,the early drying shrinkage of high performance geopolymer concrete decreases in turn.The early drying shrinkage of high performance geopolymer concrete specimens is between 1411×10^(-6)-4387×10^(-6),and the early autogenous shrinkage is between 856×10^(-6)-1188×10^(-6).With the increase of age,the drying shrinkage of high performance geopolymer concrete increases rapidly in the early stage,and the autogenous shrinkage decreases slightly first and then increases rapidly,and then gradually tends to be gentle.The early shrinkage curve can be divided into three stages(rapid growth stage,slow growth stage and stable stage).Based on the measured values of early drying shrinkage,the applicability of GL2000 model to the early drying shrinkage curve of high performance geopolymer concrete was verified.