چكيده به لاتين
Cement mortar and concrete, despite their widespread applications, have drawbacks and weaknesses. These weaknesses include low tensile and flexural strength and high shrinkage during drying and chemical resistance to corrosion. Some of these weaknesses can be remedied by polymer-based mortar or concrete. Two types of latex (styrene butadiene rubber and polyvinyl acetate) were used in the manufacture of latex modified concrete (LMC) with polymer to cement ratio (10% -15% -20%). In this study, we investigated the mechanical properties and durability of concrete as a repair concrete layer on out-of-service concrete and performance. Experiments performed on the LMC include concrete performance, flexural, tensile and compressive strengths, total porosity and water absorption, and shrinkage. Also, to evaluate the dimensional compatibility of the base concrete and repair the restrained shrinkage, bond strength has been performed. Freeze-thaw resistance testing has also been carried out as the latest durability test. The results show improvement in bending and tensile strength of concrete made with SBR latex and decrease in compressive strength of SBR and PVC modified concrete. The best mechanical performance associated with SBR10% was compressive strength loss of 4%, tensile strength increase of 14% and flexural strength increase of 13%.The results show a decrease in water absorption and porosity of 38% and 40%respectly in styrene butadiene rubber modified concrete by replacing 10% polymer with cement, resulting in a decrease in SBR based concrete shrinkage. The bond strength between LMC and base was higher than that of control and base concrete. According to the results of the shrinkage, the lowest shrinkage was for SBR20% concrete with 55.5% decrease compared to the control sample and the highest shrinkage was for PVA20%. Also, the results of Scaling Resistance of Concrete Surfaces Exposed to Deicing Chemicals showed excellent performance of concrete modified with both latex types, which appeared in all cycles without scaling, whereas the control concrete with severe scaling.
