Enhancement of bonding efficiency between overlay and substrate concrete using Styrene-Butadiene Rubber Latex and different surface roughness methods

Abstract

The present study aims to accurately assess the binding efficiency between the substrate and the overlay using Styrene-Butadiene Rubber Latex (SBR) and ordinary Portland cement as a bonding mortar. Four different roughening techniques for the substrate surface were compared: surface roughening with a steel wire brush;, surface roughening by scarifying double parallel grooves in one direction; surface roughening by scarifying double parallel grooves in two directions; and surface roughening by scarifying double parallel grooves in one direction, drilling the substrate, and fixing screws in the double grooves. A total of 24 repaired prism specimens were tested for flexural strength with 45° and 90° angles between overlay and substrate. The cylinder specimens were also tested for splitting tensile strength and for slant shear strength at a 30° angle between overlay and substrate. The repaired specimens were cured at 23±2°C for 28 days before the flexural, splitting, and slant shear strength tests were performed. The experimental tests indicated that the best bonding strength was obtained in flexural strength tests when the surfaces were roughened by scarifying, carefully drilling the substrate, and fixing screws in the double grooves at a 45° angle between overlay and substrate.

Keywords

• cement-sbr mortar
• substrate surface roughness
• repaired concrete
• flexural strength
• splitting strength
• slant shear strength