Study On Fracture Performance Of Basalt Fiber Reinforced Concrete

As the most common building material,concrete is widely used in hydraulic engineering construction,but the easy cracking,low tensile strength and poor toughness of concrete have limited its application and development in large hydraulic structures.As a new material,basalt fiber reinforced concrete has the advantages of excellent toughness,high strength and good stability,which effectively restrain the generation and development of cracks.Therefore,it is of great practical significance to study the crack resistance of basalt fiber reinforced concrete for preventing cracks and improving durability of concrete structures.In this paper,the fracture mechanical properties of basalt fiber reinforced concrete are analyzed and studied by means of experiments,scanning electron microscopy and numerical simulation,in order to systematically explain the toughening and reinforcing mechanism of basalt fiber reinforced concrete.The main conclusions are as follows:(1)The basic mechanical tests of basalt fiber concrete for compression,tension and bending are carried out.The microstructure of the basalt fiber concrete is observed by electron microscopy.After analysis and comparison,it is found that the blending length is 6mm and the dosage is 2‰.Basalt fiber can better enhance the mechanical properties of concrete.(2)The test results of fracture mechanical properties of basalt fiber reinforced concrete are analyzed.The calculated values of each fracture parameter are obtained,and the concrete P-CMOD curves of different fiber content are drawn.The results show that basalt fiber can improve the peak load and toughness of concrete materials.(3)A meso-damage mechanics model suitable for the mechanics properties of fiber reinforced concrete is proposed in this paper.The experimental and numerical results of basalt fiber reinforced concrete are compared and analyzed to verify the feasibility of the model.The influence of aggregate mass ratio on the specimen of basalt fiber reinforced concrete is explored by the model.The effects of fiber concent and fiber length on the mechanical properties of concrete are quantitatively described by regression analysis method.Based on the size effect theory of energy release,the size effect of basic mechanical properties of basalt fiber reinforced concrete is analyzed,and the corresponding fitting curve of size effect law is obtained.(4)The numerical simulation results of the three-point bending beam are compared with the experimental results.The correlation coefficients of the calculation results of different working conditions are above 0.95.The model is used to simulate the behavioral characteristics of the basalt fiber reinforced concrete in fracture mechanics.The-CMOD curve increases as the size of the test piece increases.