非离子纤维素醚改性水泥浆的孔结构.pdf

第16卷第1期
建筑材料学报
Vol 16. No. 1
2013年2月
JOURNAL OF BUILDING MATERIALS
Feb.,2013
文章编号:1007-9629(2013)01-0121-07
非离子纤维素醚改性水泥浆的孔结构
欧志华2,马保国2,震守卫2
(1.湖南工业大学土木工程学院,湖南株洲412007;
2.武汉理工大学硅酸盐建筑材料国家重点实验室,湖北武汉430070)
摘要:通过表观密度测试及宏观、微观孔结构观察,研究不同分子结构非离子纤维素醚对水泥救孔
结构的影响.结果表明,非离子纤维素醚会导致水泥浆孔隙率增加;非离子纤维素醚改性水泥浆黏
度相近时,羟乙基纤维素醚(HEC)改性水泥浆的孔隙率比羟丙基甲基纤维素醚(HPMC)和甲基纤
维素醚(MC)改性水泥浆小;基团含量相似的HPMC纤维素醚,黏度/相对分子质量越低,其改性
水泥浆孔隙率越小,非离子纤维素醚掺入水泥浆后,降低了液相表面张力,使得水泥浆容易形成气
泡;非离子纤维素醚分子定向吸附在气泡气一液界面,同时还增加了水泥浆液相黏度,使得水泥浆稳
定气泡的能力增强
关键词:非离子纤维素醚;水泥浆;孔结构;分子结构;表面张力;黏度
中图分类号:TU528.0
文献标志码
doi:10.3969/j.issn.1007-9629.2013.01.023
Pore Structure of Cement Pastes Modified by Non-ionic Cellulose Ethers
OU Zhi-hua", MA Bao-gu
JIAN Shou-wei
(1. School of Civil Engineering, Hunan University of Technology, Zhuzhou 412007, China; 2. State Key Laboratory
of Silicate Materials for Architectures, Wuhan University of Technology, Wuhan 430070, China)
Abstract: The effect of non-ionic cellulose ethers(NCE) with different molecular structure on pore struc
ture ot cement pastes was investigated by apparent density test, visual observation, optical microscope and
SEM. The results indicate that the addition of NCE results in higher porosity in cement pastes. The poros
ity in cement pastes modified by hydroxyethyl cellulose ethers(HEC) is lower than that in cement pastes
modified by hydroxypropyl methyl cellulose ethers(HPMC) and methyl cellulose ethers(MC)when their
viscosity is close to each other. If HPMC with close substituent group content(by mass) is added, the low-
er the viscosity/relative molecular mass of HPMC, the lower the porosity of the cement pastes. The addi
tion of NCE reduces the surface tension of liquid in cement pastes and leads to form bubble more easily
The ability of cement pastes to stabilize bubbles is enhanced by the addition of NCE because NCE mole-
cules are adsorbed on the gas-liquid interface of bubbles orientationally and the viscosity of cement paste
increased
Key words: non-ionic cellulose ether(NCE); cement paste; pore structure; molecular structure; surface
tension; viscosity
非离子纤维素醚(以下均简称为纤维素醚)具有混凝土等新型水泥基材料中得到广泛应用.用于
优良的增稠和保水作用,在干混砂浆2、自密实水泥基材料中的纤维素醚通常包括甲基纤维素醚
收稿日期:2011-08-25;修订日期:2011-11-07
基金项目:国家自然科学基金资助项目(50902107);国家重点基础研究发展计划(973计划)项目(2009CB623201)
第一作者:欧志华(1975-),男,湖南常宁人,湖南工业大学高级工程师,博士.主要从事水泥基复合材料和建筑节能研究.E-mail: zihao