Experimental study on flexural behavior of UHPC-NC composite beams

With the increase of service life, bridges will deteriorate under various factors and it is necessary to repair and strengthen the existing structures. Ultra High Performance Concrete (UHPC) has excellent mechanical properties, and it is an ideal material for building composite members and strengthening existing concrete structures. In this paper, three UHPC- normal strength concrete(UHPC-NC) composite beams and one reinforced concrete beam were tested. The loading process, crack development mode and failure mode of UHPC-NC composite beams were recorded. The mechanical behavior of UHPC and reinforcement during the loading process were emphatically studied. It was verified that the high tensile strength of UHPC contributes to the flexural resistance of composite beams. When calculating the flexural strength of UHPC -NC composite beams, the high tensile strength of UHPC should be fully considered. Secondly, the flexural capacity of the composite structure can be greatly improved by arranging longitudinal reinforcement in the UHPC layer. Meanwhile, nonlinear finite element analysis (FEA) is carried out for the test beam. The results show that the FEA results are in good agreement with the test results.