Numerical analysis of PBO FRCM-concrete joints

The use of fiber reinforced composites for strengthening and retrofitting existing reinforced concrete (RC) structures has been gaining popularity in the last few decades. Fiber reinforced polymer (FRP) composites have been heavily studied and proven successful for bending and shear strengthening of RC beams and slabs and for confining axially loaded RC elements. Recently, fiber reinforced cementitious matrix (FRCM) composites, which are comprised of high-strength fiber net embedded within inorganic matrices, have been proposed as an alternative to FRP composites. The bond behavior of fiber reinforced cementitious matrix (FRCM) composites applied to concrete elements is investigated in this paper by means of a three-dimensional numerical analysis. The FRCM-concrete joints studied are part of an extensive experimental campaign conducted using the single-lap direct-shear test set-up and include specimens both with and without the external layer of matrix. The input data of the numerical models are obtained applying a fracture mechanics approach that allowed for studying the shear stress - slip relationships that characterize the matrix-fiber interfaces. The load responses and strain profiles obtained from the numerical models of specimens with and without the external matrix layer are compared with the corresponding load responses and strain profiles observed in the experimental tests. A good agreement between the numerical solutions and the experimental results is obtained.