2.3.1. Compressive Strength

After 7, 14, and 28 days of water curing, the compressive strength of cylindrical specimens was determined in three-time intervals. From each mix, three specimens were tested on a compression testing machine (CTM) with a loading rate of 2.4 kN/s, and the average value was noted according to [25] (Figure 2).

**Figure 2.** (**a**) Compressive Testing machine (**b**) Crushed cylindrical specimen.
