Effect of polymer cement modifiers on mechanical and physical properties of polymer-modified mortar using recycled waste concrete fine aggregate

Various polymer-modified mortars using recycled waste concrete fine aggregate were prepared and investigated for the purpose of measuring their feasibility of recycling. Styrene-butadiene rubber (SBR) latex and polyacrylic ester (PAE) emulsion were used and compared as polymer cement modifiers. The replacement ratio of waste concrete fine aggregate (WCFA) was also changed to investigate its effect on the physical properties. The addition of a polymer cement modifier into the mortar reduced the water-cement ratio significantly; PAE was more effective at reducing the water-cement ratio than was SBR. There was slight difference in water absorption between the SBR- and PAE-modified mortars, and it decreased drastically at a 20 % content of polymer cement modifier for both SBR and PAE. The compressive strengths decreased after the addition of the polymer cement modifiers; the PAE emulsion-modified mortar showed higher flexural strength than did the SBR latex-modified one. After the hot water resistance test, the compressive strength of the 20 % polymer cement modifier had a slightly lower value than did that at 10 % for both SBR and PAE; the rate of decrease in flexural strength of the specimen was more rapid in case of the PAE-modified mortar relative to that of the SBR-modification.