Importance of the surface roughness of a steel fibre pulled out from cement paste by slowly increasing load cycles

Pull-out tests of fibres were conducted using slow cyclic tension to evaluate the behaviour bond between cement paste and steel with different types surface roughness. Even though load amplitude increases in small steps cycles, development residual slip increment proves absence a complete at beginning loading. During steps, evolves deceleration, steady, acceleration stages. The stiffness during ascending descending parts load-slip curve up last indicating that loading compacts matrix near fibre surface. growth roughness amount adhered pulled out, explaining changes increase pull-out capacity these fibres. • fibre-matrix was studied for slowly growing tensile cycles. grew despite per cycle. Residual developed Image analysis indicated