Research on the bonding performance of TRC permanent formwork and cast-in-place concrete

•The bonding properties of TRC formwork and concrete are analyzed.•The interface bonding between TRC formwork and concrete is good.•The ultimate bearing capacity of the treated interface specimens is improved.•The specimens after the interface treatment suppressed the development of cracks. The performance of the interface bond between the TRC permanent formwork and cast-in-place concrete is a key factor that determines whether the formwork can exert sufficient mechanical properties to replace traditional formwork. Sufficient performance of the TRC permanent formwork can further promote its application in engineering practice. This paper presents the results of a three-point bending test performed on a TRC formwork superimposed plain concrete beam with prefabricated cracks. The influences of various interface treatment methods, interface agent types, TRC formwork thicknesses, chopped fibre contents, textile distribution rates and other factors on the bonding performance of the interface between the TRC permanent formwork and cast-in-place concrete are considered. The study found that regardless of whether the interface is processed, the interface bonding performance between the TRC permanent formwork and the cast-in-place concrete is better than that between traditional formwork and cast-in-place concrete. After the interface is processed, the ultimate bearing capacities of the composite beam specimens are improved to varying degrees, and the crack development mode is improved. Treating the interface, increasing the thickness of the TRC formwork, increasing the formwork distribution textile rate, adding chopped fibres and other treatment methods can reduce the strain of the interface between the TRC formwork and cast-in-place concrete.