EXPERIMENTAL STUDY ON THE BOND STRENGTH BETWEEN REPAIR MORTAR AND CONCRETE SUBSTRATE

Abstract

Concrete is widely used in infrastructure projects worldwide, including Timor-Leste, a newly independent country struggling to advance its social and economic development. Concrete repair and rehabilitation are critical for extending its service life. The effectiveness of the repair depends on the strength of the bond between the repair material and the concrete substrate. This experimental study focused on the bond properties of ordinary performance cement mortar (OPCM) and polymer-modified cement (PMC) mortar and also examined the interfacial bond strength under tension, shear, and a combination of both. Slant shear and double shear tests were conducted to investigate the bond strength. The test results showed that the epoxy resin used as an interfacial bonder exhibited a lower bond strength than the other test parameters. The results obtained from the tests indicated that the expected interfacial bond strength was achieved between the repair material and concrete substrate using the proposed method. The use of OPCM in repairs is considered sustainable and applicable in countries where access to repair materials is difficult, as experiments have shown satisfactory results with existing repair materials and combinations.