Fatigue behaviour of strain-hardening cement-based composites (SHCC)

The safe use of strain-hardening cement-based composites (SHCC) in structural and non-structural applications often requires a solid knowledge of the mechanical performance of this novel material under cyclic loading. The article at hand presents the findings of a comprehensive experimental investigation focusing on fatigue behaviour and failure mechanisms of SHCC made with polyvinyl-alcohol fibre and subject to various loading regimes. Uniaxial tests were performed both as tension-swelling tests and alternating tension-compression cyclic tests. While the upper reversal point was controlled - depending on the chosen regime - either by a given deformation increment or load level, the lower reversal point was always controlled by a given load value. The experiments revealed a pronounced decrease in the number of load cycles to failure with increasing upper stress level, smaller applied strain increments and with transition from purely tensile loading to alternating tension-compression regime. Furthermore, the effects of these tests parameters on strain capacity and other material properties of SHCC were investigated. On the basis of the test results, evaluation of the crack patterns and microscopic analysis of the conditions of the fracture surfaces, four various failure modes were identified, each of them typical for particular cyclic loading scenarios.