砂率及机制砂特性对混凝土流动性与颗粒膜层厚度的影响

硅酸盐通报 ›› 2022, Vol. 41 ›› Issue (9): 3068-3076.

砂率及机制砂特性对混凝土流动性与颗粒膜层厚度的影响

肖世玉, 彭丙杰, 吴涛, 罗小东, 陶俊

成都建工赛利混凝土有限公司,成都 610000

收稿日期:2022-05-09 修回日期:2022-06-08 出版日期:2022-09-15 发布日期:2022-09-27
作者简介:肖世玉(1991—),女,助理工程师。主要从事混凝土研究。E-mail:378447647@qq.com
基金资助:
四川省科技重点研发项目(2021YFG0272)

Effects of Sand Ratio and Machine-Made Sand Characteristics on Concrete Fluidity and Film Thickness of Particles

XIAO Shiyu, PENG Bingjie, WU Tao, LUO Xiaodong, TAO Jun

Chengdu Seller Concrete of CDCEG, Chengdu 610000, China

Received:2022-05-09 Revised:2022-06-08 Online:2022-09-15 Published:2022-09-27

摘要/Abstract

摘要： 在保持混凝土胶材总量、水胶比不变情况下,设计了不同砂率、不同种类砂搭配的混凝土配合比,通过测试混凝土扩展度、扩展时间(T₅₀₀),结合浆膜层厚度(PFT)、水膜层厚度(WFT)计算,详细分析了PFT、WFT与新拌混凝土流动性的关系。结果表明,混凝土流动性受PFT和WFT的影响较大,且不同种类砂搭配制备混凝土的流动性、PFT、WFT均存在较大差异。混凝土扩展度随PFT、WFT的增加而增加,且关联度较高,T₅₀₀随PFT、WFT的增加而减少,但相关性较差。PFT、WFT的变化主要源于机制砂石粉含量、细度模数以及骨料空隙率的变化,当石粉含量过高时,虽然会引入更多浆体使PFT增加,但同时也会引起体积水胶比减小,比表面积增大,导致WFT变小,混凝土流动性反而变差。

关键词: 混凝土, 流动性, 浆膜层厚度, 水膜层厚度, 砂率, 细度模数, 石粉含量

Abstract: Different kinds of mix proportion of concrete, e.g. sand ratio and sand mix, were designed. By testing the concrete slump flow, slump-flow time (T₅₀₀) and combining with the calculation of paste film thickness (PFT) and water film thickness (WFT), the relationships between PFT, WFT and fluidity of fresh concrete were analyzed in detail. The results show that the fluidity of concrete is greatly effected by PFT and WFT, and the fluidity, PFT and WFT of concrete prepared with different kinds of sand are quite different. The slump flow of concrete increases with the increase of PFT and WFT, and the correlation is high between the fluidity and, and WFT. The T₅₀₀ decreases with the increase of PFT and WFT, but the correlation is poor between T₅₀₀ and PFT, WFT. The changes of PFT and WFT are mainly due to the changes of the fine content, fineness modulus of machine-made and aggregate porosity. When the fine content of sand is too high, although more slurry will be introduced to improve PFT, it will also reduce the volume water binder ratio and improve the specific surface area, resulting in the decrease of WFT and the deterioration of concrete fluidity.

Key words: concrete, fluidity, paste film thickness, water film thickness, sand ratio, fineness modulus, fine content

中图分类号:

TU528

肖世玉, 彭丙杰, 吴涛, 罗小东, 陶俊. 砂率及机制砂特性对混凝土流动性与颗粒膜层厚度的影响[J]. 硅酸盐通报, 2022, 41(9): 3068-3076.

XIAO Shiyu, PENG Bingjie, WU Tao, LUO Xiaodong, TAO Jun. Effects of Sand Ratio and Machine-Made Sand Characteristics on Concrete Fluidity and Film Thickness of Particles[J]. BULLETIN OF THE CHINESE CERAMIC SOCIETY, 2022, 41(9): 3068-3076.

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