An experimental investigation on the mechanical characteristics of Steel Fibre Reinforced Alkali Activated Concrete incorporating industrial and agro wastes

In recent years, there has been growing interest in alternative cementitious materials that can provide enhanced performance and sustainability compared to traditional Portland cement-based concrete. Alkali-activated concrete (AAC) made of various industrial wastes has emerged as a promising alternative due to its lower carbon footprint and excellent mechanical properties. Rice husk ash, a by-product of rice milling being rich in amorphous silica and possessing pozzolanic properties, when added to AAC can enhance the strength due to its contribution for the formation of additional binding phases. However, to further enhance the overall performance of AAC, the incorporation of fibres has gained significant attention. Fibre reinforcement in AAC offers improved mechanical strength, enhanced crack resistance and increased ductility, making it suitable for various structural applications. This paper aims to provide an in-depth exploration of AAC reinforced with steel fibres (SFRAAC). It presents an experimental investigation on the mechanical properties of SFRAAC with different types of binders (Fly ash, Slag as industrial wastes and Rice Husk Ash as agro waste) and dosages of fibres (steel). The study focuses on understanding the effects of steel fibre inclusion on compressive strength, tensile strength and flexural strength of M30 grade AAC at the age of 28 days designed according to IS: 17452:2020. The concrete mix design parameters, alkali activator composition, curing conditions and fibre dosages are carefully controlled to ensure accurate comparisons and reliable results. A highest slump value of 52 mm is achieved for a combination with 30% fly ash, 60% Slag and 10% rice husk ash. A highest mean compressive strength of 79.4 MPa and splitting tensile strength of 4.71 MPa are attained with 30% fly ash and 70% slag combination at a volume fraction of 0.1%, and a highest mean flexural strength of 10.91 MPa is attained for the same combination at a volume fraction of 0.4%.