不同配合比的HECC力学与干缩性能试验研究  

Experimental study on mechanical and drying shrinkage properties of HECC with different mix proportions

作　　者：胡伟 李家正[2] 石妍[2] 卢晓春[1] HU Wei;LI Jiazheng;SHI Yan;LU Xiaochun(College of Hydraulic and Environmental Engineering,China Three Gorges University,Yichang 443002,China;Department of Materials and Structure,Changjiang River Scientific Research Institute,Wuhan 430010,China)

机构地区：[1]三峡大学水利与环境学院,湖北宜昌443002 [2]长江科学院材料与结构研究所,湖北武汉430010

出　　处：《人民长江》2024年第4期222-229,共8页Yangtze River

基　　金：湖北省自然科学基金项目(2022CFD026);国家自然科学基金项目(52179122,U2040222)。

摘　　要：水工超高韧性水泥基复合材料(HECC),具有中等强度、低弹性模量、较强的热稳定性、可控的裂缝宽度及较宽泛的原材料来源等特性,由于其中无粗骨料、胶凝材料用量高,其体积变形明显高于普通水工混凝土,因此必须合理控制体积稳定性。为探寻不同因素对HECC干缩及力学性能的影响及其发展规律,开展了不同水胶比、纤维掺量、粉煤灰以及硅灰掺量下的HECC流动性能、抗压抗折强度和干缩性能试验,并利用SEM对水化产物进行观察。结果表明:在用水量一定的情况下,水胶比由0.25增至0.35,试样的28 d抗压强度、抗折强度和干燥收缩分别降低17.3%,9.7%和20.5%;纤维掺量显著影响HECC抗折强度,掺量2.0%比1.0%时的抗折强度高30.0%,但对抗压强度与干缩性能影响不大;粉煤灰掺量对HECC抗压和抗折强度影响较大,且抗压抗折强度随着粉煤灰的增大而逐渐减小,掺量60%时对应的抗压强度和抗折强度较40%时分别降低30.4%和18.2%,粉煤灰掺量增加能够大幅度降低HECC干燥收缩,掺量60%时的干缩率较40%掺量时降低23.5%;硅灰能提升HECC早期抗压抗折强度,且随着硅灰掺量的增加趋势逐渐变缓,但硅灰对HECC的干缩不利,会增大HECC干燥收缩,掺6%时干缩率较基准组增长13.6%。Hydraulic Engineered Cementitious Composites(HECC)has the characteristics of medium strength,low elastic modulus,strong thermal stability,controllable crack width and wide source of raw materials.Because there is no coarse aggregate in HECC and the amount of cementitious material is high,the volumetric deformation of HECC is significantly higher than that of ordinary hydraulic concrete,so the volumetric stability must be reasonably controlled.In order to explore the influence of different factors on the drying shrinkage and mechanical properties of HECC and their development rules,the flow performance,compressive and flexural strength and drying shrinkage performance tests of HECC under different water-binder ratio,fiber content,fly ash and silica fume content were carried out,and the hydration products were observed by SEM.The results showed that when the water consumption was constant,the water-binder ratio increased from 0.25 to 0.35,and the 28 d compressive strength,flexural strength and drying shrinkage decreased by 17.3%,9.7%and 20.5%,respectively.The fiber content significantly affected the flexural strength.The flexural strength of HECC with 2.0%fiber was 30.0%higher than that with 1.0%fiber,but it had little effect on compressive strength and dry shrinkage.The content of fly ash had a great influence on the compressive and flexural strength of HECC.The compressive and flexural strength decreased gradually with the increasing of fly ash.The compressive strength and flexural strength of HECC with 60%fly ash were 30.4%and 18.2%lower than those with 40%fly ash.The increasing of fly ash content can greatly reduce the drying shrinkage.The drying shrinkage of HECC with 60%fly ash was 23.5%lower than that of 40%fly ash.The addition of silica fume can improve the early compressive and flexural strength of HECC,and with the increase of silica fume content,the increasing trend gradually slowed down.However,the addition of silica fume was not conducive to the drying shrinkage of HECC,which would increase the drying

关 键 词：HECC 干燥收缩 抗压强度 抗折强度 

分 类 号：TV431[水利工程—水工结构工程]