Surgical face masks as reinforcement to improve the tensile mode fracture toughness of reinforced concrete under three-point bending tests

A set of experimental three-point bending tests and numerical simulations for using surgical masks as reinforcing layers in concrete samples were carried out. Different samples were prepared for analysis with changes in the number and position of the masks. The tensile strength of concrete was measured at 2.1 MPa, while that of face musk was 4.3 MPa. In these samples, fracture patterns, maximum load, fracture toughness of state I, fracture energy, and external work at the point of peak load were investigated based on the theory of fracture mechanics. The fracture procedure of specimens without face masks evolves quicker than the specimens with face masks. When the face mask was situated upper the notch, the fracture toughness increased rapidly by increasing the face mask number. When one face mask was situated upper the notch, the fracture toughness decreases by increasing the distance between the face mask and the lower boundary. When the face mask goes through the notch, the fracture toughness has the maximum value. It decreases by increasing the distance between the face mask and the lower boundary. When two face masks exist in the model, the fracture toughness decreases by increasing the distance between the face mask and the lower boundary. In addition, the external work decreases by increasing the distance between two face masks.