Page - 1048 - in Book of Full Papers - Symposium Hydro Engineering

Eight pieces of concrete cube specimens are poured in one batch with a strength of C30, a size of 100mm in length, 50mm in breadth and 300mm in height. Grinding papers are used to polish the concrete surface to be measured. In addition, dry cleaning cloth is used to clean the surface. (2) FRP Plates Yao Jian [9] and his fellows pointed out that when the breadth ratio between the FRP plate and concrete was equal or higher than one fourth, the de-bonding development process before the specimen damage can hardly be observed. The failure happened all of a sudden with no pre-signs. Therefore, the breadth of FRP plate is set as 20mm. The length of plate is determined by the sum of different bonding length and clamping length in accordance with the testing requirements. (3) The bond between concrete and FRP plates The cut concrete specimen and FRP plate are bonded with resin adhesive. The bonding lengths include eight different types: 80mm (Type SS-80), 90mm (Type SS-90), 100mm (Type SS-100), 110mm (Type SS-110), 120mm (Type SS- 120), 150mm (Type SS-150), 160mm (Type SS-160) and 180mm (Type SS-180). Stick FPR plate to the concrete surface to be measured with resin adhesive and use rollers to squeeze the bubbles out. Place weight on FRP plate for three days to guarantee that FRP plates are totally stuck with concrete. When the adhesive completely sticks the concrete specimen and FRP plate tightly, install the specimen on the equipment and conduct the test. 2.3. EXPERIMENTAL APPROACH This experiment adopts optical measurement technique to measure the deformation of FRP plate surface. In order to acquire speckles for optical measurement, two colors-black and white, are sprayed on the surface to be measured respectively. Connect the data line of optical measurement camera with the computer, observe the computer screen, and adjust the height and focal length of camera until the speckles on FRP plate can be clearly seen. Set the photograph frequency as five pics per second. Place the installed testing equipment fixed with FRP plate-concrete specimen on the 10t testing machine. Adopt monotonic loading mode under displacement control, the tensile speed is 0.03mm/min. The model diagram of direct shearing equipment and the diagram of direct shearing equipment are shown in Fig. 1. Fig. 1 Direct shear apparatus model 1048