Pull out test on polyethylene terephthalate fiber to evaluate the critical length in cementitious matrix

ABSTRACT

This study investigates the adhesion efficiency between recycled PET fibers and the cementitious matrix, aiming to determine the critical anchorage length of the fibers in reinforced concrete. Pull-out tests were performed to evaluate the fiber-matrix interaction and the maximum shear stress. The results indicated that fibers with anchorage lengths of 20 and 30 mm presented slippage, while fibers of 40 and 50 mm showed deformation without slippage, evidencing the need for a longer embedment length to improve anchorage and stress distribution. Scanning Electron Microscopy (SEM) analysis revealed that the smooth surface of the PET fibers impairs adhesion with the matrix, suggesting that for the use of this material, longer embedment lengths improve the performance of reinforced concrete. The study concludes that the minimum critical anchorage length is 40 mm for better stress transfer.

Keywords:
Pull out; Pet fibers; Critical size; Cementitious matrix; Shear stress