RESEARCH OF THE STRENGTH AND DEFORMABILITY OF ROAD SLABS REINFORCED WITH SMALL DIAMETER COMPOSITE REINFORCEMENT

Abstract

Scientific work is devoted to research of stress-strain state of PD2-9,5 road slabs, reinforced with identical frames made of fiberglass reinforcement and metal reinforcement A500C of the 10th diameter. In order to verify the hypothesis regarding the possibility of equal-strength replacement of metal reinforcement with composite reinforcement of a smaller diameter, glass composite reinforcement of the 7th diameter was used to reinforce the slab. To determine the actual bearing capacity, due to the application of a uniformly distributed load, a calculation scheme with a "beam" slab, i.e., resting on two supports, was applied. During the experiment, it was determined that the appearance, formation, and opening of normal cracks in both tested slabs corresponds to the "classic" nature of crack formation in reinforced concrete elements operating in bending. After the destruction of the slab reinforced with fiberglass composite reinforcement, numerous structural cracks of a mesh nature were recorded, with different degrees of branching, mainly in the lateral central part and in the lower (stretched) zone. The total final deflection in the center of the slab reinforced with fiberglass composite reinforcement at the time of failure was 3,41 cm, which significantly exceeds the permissible value for the span length L < 3 m. At the same time, the total deflection in the center of the slab reinforced with metal reinforcement at the current maximum uniformly distributed load ( without complete destruction of the slab) is 1,06 cm, which meets the generally accepted construction requirements. It was established that the actual bearing capacity of the road slab reinforced with A500C metal reinforcement is higher by 2,3 times than the bearing capacity of a slab with similar fiberglass composite reinforcement. This fact does not give grounds for asserting the effective use of Ø7 mm fiberglass composite reinforcement as a conditionally “equal-strength” replacement of Ø10 mm class A500C metal reinforcement when reinforcing elements of a similar type. To ensure structural requirements, it is necessary to significantly increase the diameter of the applied composite reinforcement, or, as an option, use combined reinforcement with a simultaneous combination of metal and composite reinforcement. Keywords: strength, composite reinforcement, stress-strain state, road slab.