Interaction effect of recycled aggregate type, moisture state, and mixing process on the properties of high-performance concretes

This paper presents the results of a laboratory study and statistical analysis to determine the effect of the combination of three key parameters on the properties of high-performance concretes with recycled aggregates: mixing procedure, aggregate moisture states, and aggregate type. The study included evaluation of slump, compressive, flexural, and splitting tensile strength, modulus of elasticity, and drying shrinkage of concretes with a water/cementitious ratio of 0.45. Statistical analysis of the experimental data included one-way analysis of variance (ANOVA) and post hoc test. The results showed that it is possible to produce high quality concretes using recycled coarse aggregates by manipulating the above mentioned parameters, which is a technical, economical, and sustainable alternative to natural aggregate concretes. The two-stage mixing approach had a positive effect on workability, strength, and drying shrinkage. Aggregates in the pre-saturated state showed higher performance than those in the oven-dried and saturated surface-dried states.