摘要
为缓解抹灰砂浆的早期干燥收缩,本文采用醋酸乙烯-乙烯(VAE)改性抹灰砂浆,通过正交试验探究了VAE、水胶比、粉煤灰、重钙对水泥砂浆早期干燥收缩的影响规律,采用灰色关联度分析了各因素对早期干燥收缩的影响程度,并采用核磁共振技术从细观尺度分析了VAE改性抹灰砂浆的孔隙结构分布。结果表明:各因素对砂浆早期干燥收缩影响程度由大到小依次为水胶比、VAE掺量、重钙掺量、粉煤灰掺量,并且最优组合为水胶比0.45、VAE掺量3%(质量分数,下同)、重钙掺量0%、粉煤灰掺量20%;VAE掺量在3%左右时,砂浆“三峰”峰值均有所降低,横向弛豫时间T_(2)谱积分面积最小,减少了有害孔和多害孔数量,此时砂浆孔结构分布均匀、形态复杂;VAE影响下砂浆的早期干燥收缩值与孔隙结构分形维数呈负相关函数,孔隙尺寸分布越均匀,形态越复杂,砂浆抵抗早期干燥收缩性能越强;实际工程中可以通过调节水胶比、VAE掺量控制砂浆的早期干燥收缩,通过调节粉煤灰、重钙掺量控制成本投入。
To alleviate the early drying shrinkage of plastering mortar,vinyl acetate-ethylene(VAE)modified plastering mortar was used in this paper.The effects of VAE,water-binder ratio,fly ash and ground calcium carbonate on early drying shrinkage of cement mortar were discussed by orthogonal test.The influences of various factors on the early drying shrinkage were analyzed by grey correlation degree,and the pore structure distribution of VAE modified plastering mortar was analyzed by nuclear magnetic resonance.The results show that the influence degree of various factors on the early drying shrinkage of mortar in descending order is water-binder ratio,VAE content,ground calcium carbonate content and fly ash content,and the best combination is 0.45 water-binder ratio,3%(mass fraction,the same below)VAE content,0%ground calcium carbonate content and 20%fly ash content.When VAE content is about 3%,the peak value of‘three peaks’of mortar decreases,and the integral area of T_(2) spectrum is the smallest,which mainly reduces the number of harmful holes and multi-harmful pores,and the distribution of mortar pore structure is uniform and the morphology is complex.Under the influence of VAE,the early drying shrinkage value of mortar has a negative correlation function with the fractal dimension of pore structure.The more uniform the pore size distribution is,the more complex the morphology is,the stronger the mortar resistance to early drying shrinkage is.In practical engineering,the early drying shrinkage of mortar can be controlled by water-binder ratio and VAE content,and the cost input can be controlled by fly ash and ground calcium carbonate content.
作者
陈成文
邵立荣
王金光
单俊伟
景宏君
郭美蓉
叶万军
CHEN Chengwen;SHAO Lirong;WANG Jinguang;SHAN Junwei;JING Hongjun;GUO Meirong;YE Wanjun(Xi’an Construction Seventh Construction Group Co.,Ltd.,Xi’an 710862,China;School of Civil and Architectural Engineering,Xi’an University of Science and Technology,Xi’an 710054,China;Road Engineering Research Center,Xi’an University of Science and Technology,Xi’an 710054,China)
出处
《硅酸盐通报》
CAS
北大核心
2024年第8期2778-2787,共10页
Bulletin of the Chinese Ceramic Society
基金
国家自然科学基金(42072319)。
关键词
醋酸乙烯-乙烯
抹灰砂浆
早期干燥收缩
核磁共振技术
孔隙结构
分形维数
vinyl acetate-ethylene
plastering mortar
early drying shrinkage
nuclear magnetic resonance
pore structure
fractal dimension
