Study On Bending Performance Of Reinforced Reactive Powder Concrete Simply Supported Beam

Reactive powder concrete(RPC)is a kind of concrete composed of cement,quartz sand,silica fume,superplasticizer,slag,and steel fiber.RPC has the advantages of ultra-high strength,low brittleness,and excellent durability.It is a kind of ultra-high-strength concrete with very wide application prospects.Because its composition and mechanical properties are different from ordinary concrete(OC),the calculation method of the bearing capacity and stiffness of its members must be different from ordinary concrete members.Based on this,this paper carried out full-scale tests on four reinforced reactive powder concrete simply supported beams to study their bending performance.And then established the calculation formulas for their bearing capacity and stiffness.The main research contents are as follows:First,the flexural test were performed on four reinforced RPC simply supported beams.Considering the effects of different reinforcement ratios,polypropylene fibers were added on the mechanical properties and failure modes of RPC.Study on the law of cracks appearing and developing during the bending test of RPC simply supported beams were obtained,and the load-displacement curves were obtained.Finally,it was found that the RPC doped with steel fiber had an ultimate pressure strain in the compression zone of 4394 ? 5200 ??,and the cracking strain was 690?820 ??,which were much larger than ordinary concrete.Secondly,the formulas of the cracking moment,the bending capacity of the normal section and the stiffness of the simply supported RPC beam were derived.Due to the addition of steel fibers,the influence of the tensile stress of the RPC tensile zone must be considered in the derivation of the formula,and the effectiveness of the formulas were verified by bending tests.The results show that the calculated values of cracking moment,bending bearing capacity and stiffness are in good agreement with the experimental values,and the calculation formula has high accuracy,which can be used for the design and calculation of the reinforced RPC beam.Finally,using ABAQUS finite element analysis software,RPC simply supported beams model was established to simulate the bending test of a reinforced RPC simply supported beam.The results show that the trend of the deflection curve obtained from the simulation is basically consistent with the test results,and the degree of coincidence is high.The plastic strain region of the numerical model is basically consistent with the crack occurrence region of the test beam,which further indicates that the model established in this paper can be used for the simulation analysis of the simply supported RPC beam.The research of this paper can be used in the design and calculation of reinforced RPC beams,and can provide experimental and theoretical references for the popularization and application of RPC in engineering.