Experimental Studies of the Strength of Reinforced Concrete Flexible Elements Forced with Carbon Fiber

Abstract

Reinforcement of reinforced concrete flexible elements with polymer composite materials has found wide application in modern construction, so the accumulation of experimental studies of the strength of such structures is relevant. This paper presents the results of experimental studies of the stress-strain state of flexible reinforced concrete elements forced with carbon fiber. Namely, six beams of three types. The first type of beams - reference samples without reinforcement. The second type of beams – beams loaded at the stage corresponding to the standard load, in the presence of cracks and deflections, reinforced with carbon fiber, by gluing it to a stretched zone with a U-shaped anchorage on the supporting areas after unloading. The third type of beams includes samples reinforced, similar to the second type of beams but before the application of loads. In addition, during the experimental study, control images of concrete, rebar and carbon fiber were tested to establish their basic physical and mechanical characteristics. The limit values of experimental bending moments in the middle of the span of samples of all series are obtained. It was found that all samples externally reinforced with carbon fiber were destroyed as a result of increasing the width and height of normal cracks located in the zone of pure bending and increasing deflections, which led to the separation of the composite material from the concrete and the indent of the concrete of the compressed zone.