*2.4. Concrete Casting and Specimen Preparation*

Three series of concrete mixes were cast in this investigation according to the three types of artificial aggregates. The coarse aggregate was used in each case to make up 20%, 40%, and 60% of the original volume. In total, ten different concrete combinations and a control concrete mixture were prepared. According to ASTM C192-18, the control mixture was poured, whereas the artificial aggregate-containing mixture required further operations to be completed. To achieve a saturated surface dry state, it was essential to soak the lightweight aggregate pellets used in the concrete mixes overnight in water, and then dry them with a towel to remove the excess water. The concrete mixtures were prepared and created using a rotating pan mixer with a 40-litre capacity.

In accordance with TS EN 12350-2, a slump cone was used to test the workability of each combination once the mixing step was completed. The hardened characteristics of the concrete mixes were investigated once the workability was established. A total of six specimens were used in the investigation of hardened properties. These included three specimens of 100 mm cubes for compression strength testing, three specimens of 100 \* 200 mm cylinders for splitting tensile and three-point load testing, three specimens of 75 \* 75 \* 280 mm for modulus of elasticity testing, and three specimens of 150mm cubes for the water permeability test. Water curing was performed for 28 days on all the concrete sample seeds that had been removed from the molds after 24 h of drying.
