Mechanical Property Performance of Polymer-Modified Calcium Sulfoaluminate Cement Mortar Systems

The purpose of this study was to assess the effect of polymer glass-transition temperature (T-g) on the mechanical property performance of mortars containing calcium sulfoaluminate (CSA) cement and vinyl acetate/ethylene dispersible polymer powder (VAE DPP). Competitive products were acquired from companies A, B, and C. Company A supplied VAE DPP with glass-transition temperatures of 64 degrees F (18 degrees C) and 19 degrees F (-7 degrees C). Company B supplied VAE DPP with glass-transition temperatures of 59 degrees F (15 degrees C) and 5 degrees F (-15 degrees C). Company C provided VAE DPP with glass-transition temperatures of 68 degrees F (20 degrees C) and degrees 8 degrees F (-22 degrees C). It is important to note that differences in glass-transition temperature result from differences in the ratio of monomers utilized for production of the liquid polymeric dispersion during reaction polymerization, where the pertinent ratio is that of ethylene to vinyl acetate for materials germane to this study. Additionally, each utilized polymer powder may also differ in constituent components comprising the polymer powder as a result of the drying process, where constituent materials should not be limited to products typically utilized for forming protective colloids or products utilized as anti-caking agents. Each polymer was tested in a standard mortar formulation with polymer/cement ratio of 2/5 and water/cement ratio of 0.48. Experimental results show that polymer modification improves the ductile performance of CSA cement mortars. Additionally, experimental results show that the glass-transition temperature of vendor-specific products influences the mechanical property performance of polymer-modified CSA cement mortars.