Early Drying Shrinkage Analysis of Vinyl Acetate-Ethylene Modified Plastering Mortar
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 and20％fly ash content.When VAE content is about3％,the peak value of'three peaks'of mortar decreases,and the integral area of T2 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.
vinyl acetate-ethyleneplastering mortarearly drying shrinkagenuclear magnetic resonancepore structurefractal dimension
万方数据
维普
