Experimental Evaluation of Mechanical Properties of Alkali-Activated Blast Furnace Slag Concrete vs. Portland Cement in Hydraulic Structures

Improving the mechanical properties and durability of concrete used in hydraulic structures has always been of interest to civil engineers. In this paper, the mechanical properties of alkali-activated concrete (AAC) were evaluated compared to ordinary portland cement concrete (OPCC) for use in hydraulic structures. In this research paper, a mix design of OPCC containing 500 kg/m3 of Portland cement and a mix design of AAC containing granulated blast furnace slag (GBFS) were made. The mechanical properties of the designs were evaluated under compressive strength, tensile strength and elastic modulus tests at 7, 28 and 90 days of curing. The test results indicate that the performance improves with increasing curing age in concrete samples. In this regard, in OPCC, the highest compressive strength, tensile strength and elastic modulus were obtained at 90 days of curing age, respectively, with values of 64.92, 5.22 MPa and 33.73 GPa, which achieved 48.79, 89.13 and 21.85 percent improvement in results compared to 7 days of curing age. In AAC, the highest compressive strength, tensile strength and elastic modulus were obtained at the 90-day curing age, which were 72.33, 4.74 MPa and 39.11 GPa, respectively, which resulted in 10.93, 60.67 and 25.35 percent improvement in results compared to the 7-day curing age. At the 90-day curing age (as the optimal age), the performance of AAC in compressive strength, tensile strength and elastic modulus tests showed 11.41% improvement, 19.9% decrease and 15.95% improvement in results, respectively. The results obtained from scanning electron microscopy (SEM) analysis on concrete samples overlapped with other tests in this study.