Study on Compression Deformation and Damage Characteristics of Pine Needle Fiber-Reinforced Concrete Using DIC

Natural fiber-reinforced concrete (NFRC) has the advantages of environmental protection, energy conservation and regeneration. However, studies conducted to improve the macro mechanical properties of concrete by pine needle fiber have achieved good results. In this paper, the deformation and compression damage of pine needle fiber-reinforced concrete (PNFRC) are analyzed by digital image correlation; a fractal dimension is used to quantify the shape of PNFRC after compression damage; and the results of scanning electron microscopy confirm the effect of fiber treatment on deformation and damage of concrete. The results showed that the horizontal strain field of PNFRC has strain concentration zones in the elastic deformation stage, indicating that the fiber enhances the deformation ability of concrete. The defined damage factor can reflect the damage of fiber-reinforced concrete (FRC). The damage curve of natural fiber concrete increases evenly and slowly compared to ordinary concrete.