Effects of Polymers on Waterproofing and Mechanical Properties of Mortar after Heat Treatment.

In this paper, emulsified asphalt powder (EAP), VAE redispersible polymer powder, and SBA emulsion as admixtures were mixed into the cement mortar. Cement mortar strength, water absorption and SEM analysis before and after heat treatment were used to investigate the effect of addition of the three polymers on heat aging resistance of cement mortar at 70 °C. The results show that the addition of three polymers can all decrease the water absorption, and the water absorption decreases with the increase of polymer content. The film-forming property of SBA emulsion is better than that of redispersible polymer powder, so its modified-mortar has the best surface waterproof effect. Compared with VAE, the effect of EAP on mortar waterproofing modification is better after heat treatment. After heat treatment, asphalt component has certain viscous flow at high temperature, and the compressive strength of EAP-modified mortar decreases after heat treatment, and the flexural strength increases first and then decreases with the increase of EAP admixture, and its strength changes mainly reflect the characteristics of asphalt components under high temperature, while those VAE-modified mortar and SBA-modified mortar mainly reflect the characteristics of traditional polymer modified mortar, the polymer film structure hinders moisture migration at the early stage of heat treatment, and the flexible polymer film structure breaks down at the later stage of heat treatment causing strength higher than that before thermal aging. [ABSTRACT FROM AUTHOR]