Effect of polymer additives on mechanical properties of high strength mortar for marine structures = Ảnh hưởng của phụ gia polymer đến một số tính chất cơ học của vữa cường độ cao cho công trình biển

Abstract

This study evaluates the effect of polymer additives on the mechanical properties of high strength modified mortar (HPMM), aiming to use it as a protective layer for reinforced concrete in a marine environment. The research utilized a redispersible polymer powder (RDP) at contents ranging from 1% to 10% and a latex emulsion at a content of 5% by mass of cement, in mortar with a water to cement (w/c) ratio of 0.2. The experiments included evaluations of flowability, compressive strength, flexural strength, and corrosion resistance in a saltwater environment (Cl⁻ ions, 3.5% NaCl solution). The results showed that as the RDP content increased from 1% to 10%, flowability ranged from 11.0 to 16.0 cm, compressive strength varied from 74.67 MPa to 81.78 MPa, and flexural strength ranged from 17.68 MPa to 19.99 MPa, showing no clear trend. Bulk density gradually increased from 2066 kg/m³ to 2238 kg/m³. HPMM modified with RDP exhibited higher compressive and flexural strengths than that with latex. Notably, the polymer modified mortar layer demonstrated superior protective capabilities, significantly reducing rebar corrosion. This study suggests that polymer modified mortar is an effective and economical solution for protecting concrete marine structures, contributing to the extension of service life of coastal infrastructure in Vietnam.