Behavior of adhesively bonded concrete-CFRP joints at low and high temperatures

This paper presents an evaluation of the results obtained from an initial study carried out at the IBMB, Technical University of Braunschweig, on the influence of temperature on adhesively bonded plate-concrete joint systems. The results of a theoretical model are also presented. The type of specimen used in this study is a three-point bending beam. The concrete specimens were prismatic in form, 100 x 100 x 700 nun without ail internal steel reinforcement, strengthened at the intradoss with two types of UD CFRP lamina 20 mm wide and 590 mm long of thickness 1.4 mm for the E = 300 GPa type and 1.24 mm for the E = 175 GPa type, The plate-bonded specimens were designed to produce bending failure under a load, by not bonding the lamina and the concrete around the midspan of the specimens. The specimens were tested to failure at -100degrees, -30degrees, and +40degreesC after an approximately homogeneous temperature distribution within the concrete specimen has been reached. For comparison only, specimens of the same type were tested to failure at room temperature. The results obtained showed varying behavior of the bonded plate-concrete joint depending oil variations in temperature. Furthermore, they showed different failure mechanisms. Greater reductions in the ultimate bond force were recorded for the test specimens strengthened with lamina having a high elastic modulus. A reasonable correlation was found between the experimental and theoretical results.