Influences of ethylene-vinyl acetate and methylcellulose on the properties of calcium sulfoaluminate cement

Calcium sulfoaluminate (CSA) cement is widely used in architecture engineering and emergency repairs. However, it still exhibits several disadvantages, such as low flexural strength and strength regression during the late curing age. Ethylene-vinyl acetate (EVA) copolymer is useful in improving the flexural strength of Portland cement. Methylcellulose can improve the water retention properties of cement based materials to ensure homogeneity during hydration and to improve the stability of hydration products. The effects of EVA and methylcellulose on the setting time, strength, and pore structure of CSA cement mortar were investigated in this study. Both polymers evidently prolong setting time and enhance flexural strength, but decrease compressive strength. The regression of strength after 7 days of curing was well controlled using methylcellulose. The hydrates and mechanism of the polymer modified CSA cement were investigated via X-ray diffraction analysis and scanning electron microscopy. (C) 2018 Elsevier Ltd. All rights reserved.