Experimental study on crack bridging in engineered cementitious composites under fatigue tensile loading

The crack bridging behaviour of Engineered Cementitious Composites (ECCs) under fatigue tensile loading is investigated experimentally in this paper. Uniaxial fatigue tension tests were conducted on pre-cracked specimens under deformation control with constant crack opening displacement amplitude. The crack bridging stress at the maximum crack opening displacement was obtained against the number of loading cycles. Eight maximum crack opening displacement levels were tested in total. The crack bridging stress was found to decrease with the increase of loading cycles. The crack bridging stress degradation is generally more significant in ECCs than in steel fibre reinforced concrete. In addition, the crack bridging stress degradation behaviour of ECCs reinforced with polymeric fibres was found to be distinct from that of steel fibre reinforced concrete with presence of accelerated stress degradation. The experiment demonstrates that it is important to take the fibre fatigue rupture into account in the analysis of mechanical behaviour degradation of ECCs and that the crack opening affects the crack bridging degradation behaviour