The effect of specimen size on the unconfined compressive strength of cement-stabilized granular mixtures made of natural and recycled aggregates

The cement-stabilization technique is employed on natural and recycled granular materials to improve their mechanical properties. The strength of these materials is assessed by the unconfined compressive strength on laboratory compacted specimens, typically after 7 days of curing. Standards and technical specifications specify different values of specimen height and diameter and different loading modes of testing. This makes the comparison between different materials and with the acceptance limits of technical specifications difficult. The research investigates the effect of specimen size and loading mode on the unconfined compressive strength of both natural and recycled cement-stabilized granular materials. The results revealed significant differences in strength due to variations in specimen size and loading mode. As expected, an increase in specimen slenderness resulted in a decrease in compressive strength. A linear regression model was developed to quantify the effect of the experimental variables on the compressive strength of the two cement-stabilized materials.