The Influence of Calcined Alumina Additives on the Mechanical Properties and Chloride-Induced Corrosion of Blended Concrete

Abstract

The development and use of blended concrete systems have been growing rapidly in the construction industry, mainly due to cost savings, energy savings, and sustainability. This paper represents the influence of Calcined Alumina (AC) on the strength and chloride-induced corrosion of concrete. AC, at various contents, was appropriately added as a partial replacement for ordinary Portland cement (OPC) in blended mixtures (3,5 and 7 % by mass of OPC). To find out its impact on the fresh properties (slump flow), hardened properties (compressive and splitting strength), and durability properties (water absorption at, rapid chloride migration coefficient, chloride penetration resistance, and corrosion resistance) depending on curing ages. Moreover, it investigates the effect of crack width on chloride penetration and corrosion rate. The results reveal that the addition of AC has a positive impact on concrete. Whereas obtained a decrease in the workability of concrete and an increase in the water demand. On the other hand, a significant increase in the compressive strength, tensile strength, and durability properties of concrete was recorded. Also, the replacement of cement with 7 % AC achieved the highest value of compressive strength (63,67 MPa) in 90 days. Also, improvements in chloride penetration resistance and corrosion rate. The presence of Al₂O₃ reduces the ingress of chloride ions into concrete considerably, leading to the conclusion that the decrease in crack width is due to a decrease in corrosion steel products and the chloride penetration concentration and depth.