机制砂石粉含量对新拌混凝土流动性能的影响  

Effect of the Stone Powder Content of Machine-made Sand on the Flowability of Fresh Concrete

作　　者：陶俊 罗小东 彭丙杰 肖世玉 黄小川 

机构地区：[1]成都建工赛利混凝土有限公司,四川成都610000

出　　处：《混凝土世界》2023年第4期47-51,共5页China Concrete

基　　金：四川省科技重点研发项目(2021YFG0272)。

摘　　要：通过改变石粉含量得到不同浆膜层厚度(PFT)和水膜层厚度(WFT)的混凝土拌合物。通过混凝土扩展度以及T500试验,研究了石粉含量变化对PFT、WFT及新拌混凝土流动性能的影响。结果表明:机制砂石粉含量最佳值为2%,当石粉含量由0%增加到2%时,对应混凝土流动性能明显改善;当石粉含量超过2%时,对应混凝土流动性能下降。石粉对新拌混凝土流动性能产生影响的内在原因是因为石粉改变了混凝土的PFT和WFT,新拌混凝土流动性主要受到PFT/WFT的共同影响,其中WFT是关键影响因素。当WFT在1.4μm以上时,无论WFT如何变化,此时混凝土扩展度以及T500随PFT改变而改变。当石粉含量在2%以内增加时,此时对应混凝土WFT均在1.4μm以上,而PFT则不断增加;当WFT在1.4μm以下时,无论PFT如何变化,此时混凝土扩展度以及T500随WFT改变而改变。当石粉含量超过2%且增加时,此时对应混凝土WFT均在1.4μm以下且随石粉含量增加而降低。Concrete mixtures with different paste film thickness(PFT)and water film thickness(WFT)were prepared by changed the content of stone power.The influence of stone powder on PFT/WFT and the flowability of fresh concrete were investigated by slump flow experiment and T 500 experiment.The results showed that the optimal stone power content of machine-made sand and was 2%.When the content of stone powder increased from 0%to 2%,the flowability of corresponding concrete was significantly improved,and when the content of stone powder exceeded 2%,the flowability of corresponding concrete decrease.The internal reason for the influence of stone powder on the flowability of fresh concrete was that stone powder changed the PFT and WFT of concrete,and the flowability of fresh concrete was mainly effected by the combination of PFT and WFT,of which WFT was the key influencing factor.When the WFT was at 1.4μm above,no matter how the WFT changed,the concrete expansion and T 500 changed with PFT.When the stone powder content increased within 2%,the correspongding concrete WFT was all at 1.4μm above,while PFT continued to increase;When the WFT was below 1.4μm,no matter how the PFT changed,the concrete expansion and T 500 changed with the change of the WFT.When the stone powder content exceeded 2%and increased,the corresponding concrete WFT was below 1.4μm and decreased with the increase of the stone powder content.

关 键 词：石灰石粉 浆膜层厚度 水膜层厚度 扩展度 混凝土流动性能 

分 类 号：TU528[建筑科学—建筑技术科学]