拌合水及水环境对泡沫混凝土性能的影响

Influences of mixing water and water environment on performances of foam concrete

研究了拌合水对泡沫混凝土的作用,并通过流值进行表征。通过体积吸水率、干湿循环性能变化反映水环境作用对泡沫混凝土性能的影响。试验结果表明,单位拌合用水量、水固比越大,泡沫混凝土的流值越大;水固比相同时,泡沫混凝土的体积密度越大,体积吸水率越高、水稳定性越好;与水固比1∶1.9的泡沫混凝土相比,水固比为1∶1.8的体积吸水率较高,干湿循环后的水稳定性较低;掺加20%粉煤灰替代水泥可一定程度上降低吸水率,提高水稳定性。新拌阶段,拌合水稀释了水泥悬浊粒子的浓度,提高流动性。硬化后,水在泡沫混凝土中的迁入、迁出对其性能产生影响,其中连通孔隙率与水分作用密切相关。

The effects of mixing water on foam concrete were studied,which were characterized by fluidity.The influences of water environment on foam concrete were reflected by the changes of volumetric water absorption and performance after dry-wet circulation.The results showed that the higher the water content and water ratio,the better the flowability.The greater the bulk density was,the greater the volumetric water absorption and water stability was,at the same W/S.The volumetric water absorption of foam concrete with W/S=1∶1.8 was higher than foam concrete with W/S=1∶1.9 but the water stability after dry-wet circulation was lower.Replacing cement with 20%fly ash could reduce the water absorption and improve the water stability to a certain degree.Mixing water thinned the concentration of cement and improved the fluidity of cement paste at the fresh mixing stage.Immigration and emigration of water in the foam concrete could have an effect upon the properties of foam concrete at the hardened stage.And the effects of water were closely related to the connected porosity.