The role of the fiber–matrix interfacial properties on the tensile behavior of FRCM coupons

Abstract

Fiber-reinforced cementitious matrix (FRCM) composites are usually mechanically characterized by means of tensile and bond tests. The former, in the clevis-grip version, is referred to by the American guidelines ACI 549.4R (2013) to determine the tensile properties of the FRCM composite. The latter, in the single-lap version, is used in the Italian guidelines CNR-DT 215 (2018) to determine the effective strain. The effective strain is the strain at which debonding occurs and therefore composite action is lost. In this paper, the poliparafenilene benzobisoxazole (PBO) fiber–matrix stress transfer law, also known as cohesive material law (CML), is employed in an analytical model that describes clevis-grip tensile tests of PBO-FRCM composites. The CML was previously obtained by the authors from single-lap shear tests. The load responses provided by the model are compared with the results of tensile tests herein presented in addition to selected tests from the literature. The experimental cracking process, tensile strength, and deformation capacity can be accurately predicted by the analytical model. The comparison indicates that the knowledge of the CML of the fiber–matrix interface allows for an accurate prediction of the main tensile properties of the PBO-FRCM coupon.