Influence of Styrene Acrylate and Styrene Butadiene Rubber on Fresh and Mechanical Properties of Cement Paste and Mortars

Polymer latex emulsions have been widely used in many repair, maintenance and concrete topping applications. Two types of polymer latex emulsions; copolymers of styrene acrylate rubber (SAR) and styrene butadiene rubber (SBR) have been incorporated into cement paste and mortar mixtures at various dosages within the scope of this research. Initially, the effects of these polymer latex emulsions on setting time and rheology of cement pastes have been investigated. At the second stage, fresh (spread flow value, unit weight) and hardened properties (flexural and compressive strength) of cement mortars incorporating SAR & SBR have been determined. Test results showed that both latex emulsions significantly extend final setting times at a constant W/C ratio. This behaviour becomes more significant at higher dosages. However, this problem can be minimized by reducing amount of water. SBR seems to be more effective in reducing the yield value and viscosity of cement pastes compared to SAR at all dosages. SBR is also more effective than SAR in terms of water reducing and plasticizing performance without causing significant compressive strength loss even at high dosages according to cement mortar test results. Besides, compressive and flexural strength improvements can be recorded at a constant workability.