NS-VAE泡沫混凝土微观分析与宏观性能研究  

Micro Analysis and Macro-properties of VAE and Nano-silica Foamed Concrete

作　　者：杨淏华 李静[1] YANG Haohua;LI Jing(School of Civil Engineering and Transportation,South China University of Technology Guangzhou 510640,China)

机构地区：[1]华南理工大学土木与交通学院,广州510640

出　　处：《广东土木与建筑》2024年第5期100-104,共5页Guangdong Architecture Civil Engineering

基　　金：轻型复合建筑系统研究,广东省科技厅项目(2024)。

摘　　要：首先分别探究了VAE乳液(Ethylene-vinylacetatecopolymer,乙烯-醋酸乙烯共聚物)和纳米二氧化硅(NS)对泡沫混凝土干密度和抗压强度等宏观性能的影响,然后对VAE与NS复合改性泡沫混凝土的改性机理进行了微观分析。研究证明当NS掺入比例在0%~1%,VAE掺入比例在2%时,NS-VAE泡沫混凝土较普通泡沫混凝土改善了孔隙率和平均孔径,提高了3 d和28 d抗压强度,减小了0~7 d干缩值。微观分析表明NS形成的晶核附着在水化产物表面,并在水化产物表面与VAE一同形成致密的凝胶网膜结构,这些致密的凝胶网膜结构减小了泡沫混凝土内部的孔隙孔径,提高了复合改性泡沫混凝土的干密度与抗压强度。总体来看,NS-VAE泡沫混凝土同时具备VAE泡沫混凝土和NS泡沫混凝土的优点,早期干缩值小,不易开裂,早期抗压强度高,具备更优秀的力学性能。This study firstly investigates the effects of VAE emulsion(ethylene-vinyl acetate copolymer)and nano-silica(NS)on the macroscopic properties such as dry density and compressive strength of foam concrete,and analyzes the modification mechanism of the concrete mixed with VAE and nano-silica(nano-silica-VAE foam concrete)through microstructure analysis.The results show that when the nano-silica ratio is between 0%and 1%and the VAE ratio is 2%,the porosity and average pore size of the concrete are significantly improved compared to ordinary foam concrete.The compressive strength value after 3 d and 28 d of curing are significantly higher than those of ordinary foam concrete and the 0~7 d drying shrinkage value of the concrete is significantly reduced.The microscopic analysis show that nano-silica adhere to the surface of the hydration products and,together with VAE,forming a dense gel-like membrane structure on the surface of the hydration products,effectively reducing the pore size inside the foam concrete and improving the dry density and compressive strength of nano-silica-VAE foam concrete.Overall,NS-VAE foam concrete combines the advantages of VAE foam concrete and nano-silica foam concrete.It exhibits low early dry shrinkage,reduced susceptibility to cracking,high early compressive strength,and superior mechanical properties.Therefore,it represents an excellent engineering material.

关 键 词：VAE乳液 纳米二氧化硅(NS) 泡沫混凝土 孔隙结构 抗压强度 干缩值 

分 类 号：TU528.2[建筑科学—建筑技术科学]