Experimental studies of reinforced concrete beams with external reinforcement of the tensioned face using composite fabrics

Abstract

The object of the study is reinforced concrete beams that are reinforced with technical polyamide (kapron) fabric produced by Branch “Khimvolokno Plant” JSC “Grodno Azot”, and fiberglass, manufactured by JSC “Polotsk-Steklovolokno”. The relevance of the stems from the need to obtain and study experimental data of the load-bearing capacity, fracture pattern, crack resistance and cracking of reinforced concrete beams reinforced with composite fabrics, since the topic of restoring the load-bearing capacity of reinforced concrete structures or their strengthening is currently very relevant. Reinforcement of bent reinforced concrete structures with composite fabrics allows using fabrics along the outer edges of the structure, as they are resistant to the external environment and are not subject to corrosion, and represent external composite reinforcement, which, together with metal reinforcement, perceive tensile forces. The most common system for the restoration of reinforced concrete structures is currently the system of external reinforcement of carbon tapes, but the use of this material is limited by high cost. The aim of the study is to experimentally confirm the possibility of effective use of technical polyamide (kapron) fabric, produced by Branch “Khimvolokno Plant” JSC “Grodno Azot”, and glass fabric, produced by JSC “Polotsk-Steklovolokno”, to strengthen the stretched face of reinforced concrete bent structures. Two reinforcement options are presented: gluing horizontal tapes along the entire length on the lower stretched face and the device of a U-shaped clip of fabrics in the stretched zone. Experimental studies have shown that the external reinforcement of the stretched zone with technical polyamide (kapron) fabric produced by Branch “Khimvolokno Plant” JSC “Grodno Azot”, and fiberglass manufactured by JSC “Polotsk-Steklovolokno” change the nature of destruction, increase load-bearing capacity of reinforced concrete beams by 16–38 % in depending on the material and method of reinforcement, affect the crack resistance and crack formation. The results of experimental studies made it possible to solve an important applied problem of the effective use of these composite materials as external reinforcement of the tension face of bending reinforced concrete beams.