Determination and Prediction of Bonding Strength of Polymer Modified Concrete (PMC) as the Repair Overlay on the Conventional Concrete Substrate

In order to achieve a durable repair overlay, high bonding strength to substrate concrete and having the least amount of cracks in overlay are the main issues. Polymer Modified Concrete (PMC) consists of Portland cement concrete with a polymer modifier. Its advantages are proper bonding strength to substrate concrete, high tensile and flexural strength and low amount of shrinkage and permeability which makes it a suitable material for repair overlays. In this paper, 24 mix designs of polymer modified concrete as the repair overlay containing two different types of modifier polymers (Styrene Butadiene Resin (SBR)-based and Acrylic-based polymers) with different replacement percentages and various amounts of silica fume was considered to investigate the effect of type and amount of polymers and also properties of the mentioned overlays on their bonding strength to the substrate concrete. Two different methods for bonding assessment had been used and compared with each other. In both polymer modifiers, maximum bonding occurred in presence of polymer with 20% of cement weight. SBR-based PMC showed stronger bonding than other type of modified concrete. According to the results, with aid of linear regression analysis and Fuzzy Logic method the bonding strengths are predicted with acceptable accuracy.