| Textile Reinforced Concrete(TRC)is a new type of composite material formed by embedding textile in fine-grained concrete,which can directionally strengthen the structure and limit cracking effectively.TRC has a wide application prospect in the field of strengthening masonry.TRC can be applied to the irregular surface of masonry and has better synergistic mechanical properties with masonry.The textile embedded in matrix has good corrosion resistance.TRC can effectively improve the shortcomings of traditional strengthening methods and has a positive effect on restoration/retrofitting masonry structures,especially the protection of heritage buildings.The interfacial bonding properties between the FRCM and masonry substrate,critical indicators used to evaluate the strengthening effectiveness,have an important influence on the mechanical properties of the structures after strengthening.However,the current research is still incomplete on the factors affecting the interfacial bonding properties between TRC and masonry as well as on the interfacial bonding properties between TRC and masonry in salt erosion environment.Therefore,it is of great practical significance to study the interfacial bonding properties between TRC and masonry.For this purpose,three parts study was carried out based on the single shear test and digital image correlation technology(DIC)in this paper.Firstly,the effects of textile types,matrix types and interfacial bond length on the interfacial bonding properties between TRC and masonry in conventional environment were studied.Especially,Engineered Cementitious Composite(ECC)was considered as the matrix to optimize the material properties of TRC.Secondly,after the masonry has been eroded and deteriorated in different dry-wet cycles and different salt solution concentrations,the effects of matrix types on TRC and erosion deterioration masonry were studied.Thirdly,the interfacial bonding properties between TRC and masonry in salt corrosive environment with different dry-wet cycles,different salt solution concentrations and different matrix types were studied.Finally,based on the test results of this research and test results collected in the available literature,the influencing factors of the interface fracture energy in the slippage failure were analyzed,and the calculation formula of the fracture energy and the ultimate load calculation method are obtained via a statistical method.The main conclusions of this paper are as follows:(1)Coated carbon textile is superior to carbon and basalt textile for the interfacial bonding properties between TRC and masonry,increasing the interface bond length is also helpful to improve the interface bond strength.Slippage failure at the interface between the fabric and matrix is the most common failure mode,the coated carbon textile exploitation ratio is the highest under this mode.The effective bond length of the different textiles were determined.(2)Under dry-wet cycles,the interfacial bonding properties between TRC/mortar and erosion deterioration masonry are decrease and slip values on the textile-matrix are reduce,the textile exploitation ratio is reduced;while as the number of dry and wet cycles increases,the interfacial bonding properties between ECC and erosion deterioration masonry are first increase and then decrease,slip values on the textile-matrix are reduce,the textile exploitation ratio is increased.Salt accumulation is not observed on the matrix-masonry interface of all the specimens.(3)Under dry-wet cycles and different salt solution concentration,the interfacial bonding properties between TRC and masonry are decreased and slip values on the textile-matrix are reduced,the textile exploitation ratio is reduced;while the interfacial bonding properties between ECC/mortar and masonry are improved,slip values on the textile-matrix are reduced,the textile exploitation ratio is increased.There is no accumulation of salt at the interface between the composite material and masonry,and the composite material does not hinder the transport and migration of salt.(4)Based on the test results of this research and test results collected in the available literature,the distribution of the failure modes of the interface between TRC and masonry substrate was statistically analyzed.For the slippage failure between textile and matrix,interfacial fracture energy between TRC and masonry substrate was obtained by Mode-II interfacial fractures based on fracture mechanic.Fracture energy is related to the elastic modulus of the textile and the tensile strength of the matrix,calculation formula of fracture energy and calculation method of the ultimate load was obtained by regression.The calculation results are more accurate.The paper contains 62 figures,12 tables,and 116 references. |
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