Effect Of Fiber On Mechanical Properties Of Textile Reinforced Concrete Slabs And Reactive Powder Concrete Beams

The investigation of the biaxial flexural properties of glass fiber textile meshes inconcrete slabs and the reinforcing effects of hybrid use of steel fiber and fiber textile meshes has guiding meaning for the application of mesh and steel fiber in structural members.The improvement of the strength and durability of concrete material can obviously reduce the size and weight of the structural members and decrease the resource occupation greatly.It is the main direction of the future development of the building materials.In this paper,ordinary concrete beams and reactive powder concrete beams with the same bearing capacity were studied.Based on the theoretical calculation and the experiment investigation,the mechanical behavior of RPC beams were analyzed,and material saving result of the reactive powder concrete is evaluated.The results are of great significance to the weight reduction of the building structures and the practical engineering application.The main contents are as follows:(1)In order to investigate the biaxial flexural properties of glass fiber textile meshes in concrete slabs and the reinforcing effects of hybrid use of steel fiber and fiber textile meshes,the alkali resistance test and two-way slab bending test were carried out.The possible replacement of conventional steel mesh by composed use of glass fiber mesh and steel fibers has been investigated.The results showed that the corrosion resistance of the AR glass fiber is better than that of the C-glass fiber.Ultimate load of concrete slabs can be improved 59%with addition of AR glass fiber textile meshes.Hybrid use of steel fiber and glass fiber textile meshes shows significant positive synthetic effect,and ultimate load and toughness of concrete slabs can be improved significantly,and failure mode of the concrete slabs changes from brittle pattern into a ductile one.The conventional steel mesh with constructive steel ratio(0.2%)can be replaced by the hybrid use of AR glass fiber mesh and steel fibers with fiber content of 30 kg/m3.(2)According to “Technical Specification for Fiber Reinforced Concrete”Structures(CECS38:2004)and previous data,ordinary concrete beams and reactive powder concrete beams with the same bearing capacity are calculated and designed.And the three dividing point bending tests were carried out.The load-deflection curve,load-longitudinal reinforcement strain curve,beam failure mode and crack development pattern of the test beams were obtained.The results show that the ratio of ultimate bearing capacity of ordinaryconcrete beams to RPC beams is close to 1.It agrees well with the design results.The load-longitudinal reinforcement strain curves of ordinary concrete beams almost coincides with the RPC beams with the same bearing capacity.Due to the incorporation of steel fibers,the number of cracks in the RPC beams increased obviously,and the width of cracks and the spacing between cracks decreased significantly.The weight of the RPC beam is about 60% of the ordinary concrete beam with the same bearing capacity,so the reactive powder concrete can be used instead of the ordinary concrete for the purpose of reducing the weight of the structural members.(3)The calculation model of flexural bearing capacity of RPC beams and the crack width calculation model of RPC beams are derived.In order to verify the reasonableness of the model,the flexural bearing capacity of RPC beams and RPC beams in other references were calculated by using this model.The calculation results show that the predictive value of the flexural bearing capacity of the RPC beam coincides quite well with the experimental value.The maximum crack width of the model is in good agreement with the experimental value,and it can be used for the analyzing and checking of the maximum crack width in the serviceability limit state of the RPC beam.