Effectiveness of Surface Preparation on the Capacity of Plated Reinforced Concrete Beams

Abstract

One of the most important methods for strengthening and repairing reinforced concrete beams is to use external bonded steel plates, however, the success of this technique depends on the effectiveness of the surface preparation of the steel and concrete beams. The International Concrete Repair Institute (ICRI) recognises ten standard concrete surface profiles (CSP), according to the level of roughness, which ranges from CSP 1 (nearly smooth) to CSP 10 (very rough). Each level of roughness is associated with particular bond strength. The purpose of this investigation is to study the effectiveness of four different levels surface preparation, namely; no surface preparation (NSP), wire brushing (WB), scabbling (SC) and hand chipping (HC), on the capacity of plated reinforced concrete beams.The quality of the surface preparation established was measured based on the flexural performance of the externally strengthened steel-concrete beams. A total of 9, 250 × 450 × 3600 mm reinforced concrete beams were prepared, strengthened with glued steel plates on their soffits, and tested under two-point static loading until failure. The results showed that beams with rougher surface preparation have a high bond strength as compared to smoother surface preparations. The increase in flexural capacity of the roughened beams in Group A ranges from 18% to 32% as compared to the control beam, whilst the increase in flexural capacity of the roughened beams in Group B ranges from 20% to 42%.