Mechanical autogenous recovery and crack sealing of natural curauá textile reinforced concrete

Abstract

This paper investigates the autogenous sealing capability of curauá Textile Reinforced Concrete (TRC). Curauá is a high-performance natural fiber with excellent tensile strength and water absorption capacity. The curauá TRC mechanical behavior was evaluated through direct tensile and four-point bending tests. The autogenous mechanical recovery was analyzed by means of repeated bending and short-time creep tests. The specimens were submitted to three different environmental conditions (RH of 55%, cycles of sprayed water and 12-h water immersion) and their influence on crack sealing was evaluated. The TRC presented strain and deflection hardening behavior with a mean crack width of 50 µm. The combination of the hydrophilic nature of curauá fibers, the matrix with high pozzolanic content and narrow cracks, contributed to the autogenous sealing of the cracks and mechanical recovery of the specimens. Even under repeated and short-time creep tests, the curauá TRC did not lose its strength or strain capacities; and the mean crack width remained close to the ones submitted to the monotonic test. When submitted to sprayed water, all cracks were partially sealed after only four cycles.