Concrete Roughness Characterization Using Laser Profilometry for Fiber- Reinforced Polymer Sheet Application

The failure of a reinforced concrete member strengthened with FRP laminates may be caused by crushing of concrete, rupture of FRP laminates, or by the de-lamination of the FRP sheet. Therefore, the effectiveness and failure mode of fiber-reinforced polymer (FRP) sheets applied to beams and columns is related to the degree of adhesion of the epoxy to the concrete surface. When a peeling or de-lamination failure can be avoided, a more effective engagement of the FRP sheet occurs which results in more efficient use of material. One of the principal factors affecting the bond behavior between the concrete and epoxy is the roughness of the concrete substrate. To prepare the bond surface, sand blasting or grinding is typically used to roughen the concrete. To that end, a portable device has been developed to measure the roughness of concrete surfaces. This device can be used as a quality control tool to characterize surface roughness and identify when an adequate surface preparation has been attained. The method uses laser striping and image analysis. The method was tested on 6 slabs of sand blasted concrete, which were sandblasted to varying degrees of surface roughness, and a series of 9 plastic model concrete surface profiles.