文献类型：期刊文献

英文题名：Effect of defoaming agent on the properties of cement mortars with hydroxyethyl methyl cellulose through adjusting air content gradient

作者：Wang, Shunxiang[1,2,3];Zhang, Guofang[2,3];Wang, Zhaojia[4];Huang, Tianyong[4];Wang, Peiming[2,3]

机构：[1]Shaoxing Univ, Sch Civil Engn, Shaoxing 31200, Peoples R China;[2]Tongji Univ, Key Lab Adv Civil Engn Mat, Minist Educ, Shanghai 201804, Peoples R China;[3]Tongji Univ, Sch Mat Sci & Engn, Shanghai 201804, Peoples R China;[4]Beijing Bldg Mat Acad Sci Res, Beijing 100041, Peoples R China

年份：2023

卷号：139

外文期刊名：CEMENT & CONCRETE COMPOSITES

收录：SCI-EXPANDED(收录号：WOS:000972668300001)、、EI(收录号：20231213777195)、Scopus(收录号：2-s2.0-85150360057)、WOS

基金：The authors greatly acknowledge the financial support of this work by the Fund of National Key Research and Development Programs in the 13th Five-year Plan of China (2018YFD1101003, 2016YFC0700905) , the Open Fund of State Key Laboratory of Solid Waste Reuse for Building Materials, and the Fundamental Research Funds for the Central Universities (22120180292) .

语种：英文

外文关键词：Cement mortars; Hydroxyethyl methyl cellulose; Defoaming agent; Air content; Mechanical strengths

外文摘要：Pore structure plays one of the most important role in the properties of cement-based materials. Hydroxyethyl methyl cellulose (HEMC) has the air entrainment effect, which may significantly change the pore structure and further affect the performance of this materials. Incorporating defoaming agent (DA) may weaken this effect, due to its defoaming effect which needs to be fully evaluated. Therefore, the working efficiency of DA and the changes of pore structure caused by stepwise adjustment of the air content were mainly studied. The results show that incorporating DA can effectively eliminate air bubbles, while the defoaming effect is weak with the air content approaching to 6.0%. There is a certain negative correlation between fresh bulk density and air content, and a positive correlation between fluidity and air content. Incorporating an appropriate dosage of DA is beneficial to control the air content of the cement mortars with HEMC, so as to ensure the cement mortars have better mechanical strengths and low drying shrinkages. With the increase of DA dosage, the large capillary pores, macro pores and total porosity all show a gradual decreasing trend due to the air content decreasing. The content of connected capillary pores in cement mortars tends to increase as the air content level decreases, but shows a small decrease at the low air content of less than 6.0%.