Experimental investigations on tensile strength and fracture toughness of a polyoxymethylene fiber reinforced concrete

The crack resistance performance of concrete materials, characterized by tensile strength and fracture toughness, is vital for the durability and structural functionality of concrete components. In this study, polyoxymethylene (POM) fibers were added into concrete to enhance the crack resistance. Firstly, three -pointbending (3 -p -b) tests and splitting tension tests were performed on notched beam and cubic specimens of plain concrete and POM fiber reinforced concrete. Then, considering the heterogeneity of concrete, the 3 -p -b and splitting tension test results were analyzed to reveal the failure behaviors of plain concrete and POM fiber reinforced concrete materials. It was found that the addition of POM fibers was beneficial for improving the fracture resistance of concrete. The Boundary Effect Model (BEM) was used to estimate the tensile strength and fracture toughness of plain concrete and POM fiber reinforced concrete materials from the 3 -p -b test results, which correlated well with those obtained from the splitting tension tests and the conventional method. Moreover, the influence of POM fiber length and volume fraction on fracture resistance was evaluated. Findings revealed that increasing fiber length and volume fraction effectively enhanced the tensile strength and fracture toughness of concrete material.