Optimisation of fine RCA content in mortar mixture based on the long-term fracture and fatigue tests

This paper presents the results of an experimental study with a focus placed on the long-term mechanical-, fracture- and fatigue analysis of mortar, in which natural aggregates (NA) were partially substituted with fine recycled concrete aggregates (RCA). Long-term tests were done at 28, 145 and 255 days under natural aging conditions. Fracture and fatigue experimental analysis took place for tensile mode I, which was enriched by fracture tests performed under a combination of tensile and shear load – mixed-mode I/II loading conditions. In total, four mixtures (reference and three with fine RCA) were tested to examine the influence of the aggregate replacement on the fracture and fatigue properties of the material. The experimental results showed that 25 % of replacement seems to be an optimum dosage of fine RCA, which improves both the fracture and fatigue properties of tested mixtures. • Mortar with various percentage of fine RCA. • Optimum dosage of fine RCA in the mixture is 25 %. • Long-term mode I fracture properties. • Mixed-mode I/II fracture properties. • Fatigue properties under frequency of 10 Hz.