Compressive mechanical properties of sprayed ECC under the coupling effect of temperature-chloride

This study investigates the deterioration mechanism of the compressive mechanical properties of sprayed ECC under different temperature chloride erosion, as well as the deterioration mechanism of the rock-sprayed ECC combined body. The results show that the deterioration of compressive mechanical properties of sprayed ECC is due to the continuous accumulation of Friedel's salt and chloride crystals to generate expansion force, which causes microcracks, and the C–S–H gel changes from dense to reticular form, deteriorating the mechanical properties. In addition, with the increase of temperature, the hydration products dissolve to form new transport channels, which aggravates the deterioration. The deterioration of combined body is related to the repeated damage to the area where chloride ions pass through. Moreover, microcracks will actively tend to the area where expansion microcracks or salting-out occurs. The phenomenon of convergence or dispersion appears in crack propagation, which aggravates the formation of more axial penetrating cracks. •The deterioration law of compressive mechanical properties of sprayed ECC under the coupling effect of temperature-chloride is obtained.•The deterioration mechanism of compressive mechanical properties of sprayed ECC is revealed by energy and microstructure characteristics.•The change law and fitting equation of erosion depth of sprayed ECC at 80 °C are obtained.•The deterioration mechanism of compressive mechanical properties of like rock-sprayed ECC combined body is explored.