Influência de anticorrosivos na aderência aço-concreto

Abstract

The performance of reinforced concrete structures depends directly on the bond between steel and concrete, since this mechanism ensures the transfer of stresses and the joint functioning of the materials. However, degradation processes—especially corrosion of the reinforcement—can compromise this interaction, reducing the lifespan of structures and increasing the risk of structural failures. Therefore, the use of anti-corrosion coatings applied directly to steel bars has become a widespread alternative in civil construction. However, it is still necessary to understand how these products interfere with steel-concrete bonding, especially in situations of reduced anchorage. In this study, the effect of two anti-corrosion coatings on the bond between CA-50 steel and concrete proportioned to 25 MPa was experimentally investigated through pull-out tests on cylindrical specimens. Bars without coating, bars with a cement-polymer-based reinforcement protector, and bars coated with a synthetic lead-based primer (red lead) were evaluated. The tests were performed with anchorage lengths of 23.7 and 15 centimeters. For the 23.7 centimeter anchorage length, the average rupture force of the uncoated bars was 14.96 kN. The bars with protective reinforcement showed 14.91 kN, while the bars coated with red lead reached 12.68 kN. For the 15 centimeter anchorage length, the average rupture force of the uncoated bars was 14.99 kN. The bars with protective reinforcement registered 11.32 kN, and those coated with red lead, 5.75 kN. It is concluded that the steel-concrete stress transfer is influenced by the type of coating and the extent of the available anchorage.