Effects of surface roughness on flexural performance of CFRP/concrete composites

Abstract

Carbon Fibre Reinforced Polymer (CFRP) composites have been progressively more utilized to strengthen the concrete members to improve its flexural performance. Flexural capacity of CFRP strengthened concrete members mainly hinge on controlling probable failure modes. The interfacial bond failure takes place owing poor surface preparation for FRP application which grounds a bond failure between concrete and adhesive eventually. Preparation of concrete substrate plays a significant role in terms of engendering strong bond between FRP - concrete interface. Achieving uniform surface roughness all through the concrete substrates is the major issue in surface preparation procedure since the uniformity of the roughened concrete substrates totally depends on the human skills and experience. Existing surface roughness quantification methods have a substantial discrepancy although a unique quantification method is essential more imperatively. In the present study, experimental investigation was focused on the flexural performance of the externally strengthened CFRP concrete beams with different types of surface preparation levels. The surface roughness of the concrete substrates was determined by means of a stan.dard quantification method. Concrete beams were subjected to three point bending test and failure modes were observed. The test results point out a significant effect on the flexural capacity of CFRP strengthened concrete beams with the surface roughness levels.