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, 250x450x3600 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%.