Research on Flexural Bearing Capacity of Reinforced Hollow Slab Beams Based on Polyurethane Composite Material Positive and Negative Pouring Method

In order to explore the construction technology of prestressed steel strand–polyurethane cement composites for strengthening hollow slab beams, two reinforced test beams (L1, L2) and one unreinforced test beam (L0) were subjected to flexural static load tests. The deflection, ductility, stiffness, strain, and bearing capacity of each test beam were used to summarize the influence of different reinforcement techniques on the flexural performance of hollow slab beams. Research shows the prestressed steel strand–polyurethane composite material was well-bonded to the hollow slab beam, which effectively inhibits the development of concrete cracks and delays the damage process of hollow slab beams, that the reinforcement effect of the test beam L1 under the reverse pouring process was remarkable, and the bending performance of the test beam L2 under the forward pouring process of the simulated real bridge was good, which was much better than that of the unreinforced beam L0. The use of tensile prestressed steel strands and forward casting of polyurethane–cement composite materials effectively improved the flexural bearing capacity of the test beams, and this reinforcement process can be further extended to engineering applications