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• Waste Marble Aggregates can be utilized in sustainable Alkali Activated Concrete. • Up to 50% of natural aggregates can be replaced with Waste Marble Aggregates. • Alkali Activated Concrete with Waste Marble Aggregates showed excellent strength. • Durability characteristics of alkali activated concrete using waste marble was studied using different methods. This study examines the use of waste marble aggregates (WMA) as a substitute to natural aggregates (NA) to produce sustainable alkali activated concrete (AAC). Sodium hydroxide (NaOH) of 8M concentration and sodium silicate (Na 2 SiO 3) were used as an alkaline activator for high calcium fly ash based AAC. NA were replaced with WMA at different weight ratios, namely 0%, 25%, 50%, 75% and 100%. Different properties like density, workability, air content, compressive, flexural and tensile strengths, along with modulus of elasticity of fresh and hardened concrete were investigated. Also, rapid chloride penetration test, oxygen permeability index test, depth of water penetration, electrical resistivity and acid resistance were also conducted to study the durability characteristics of the sustainable AAC. Results of this study showed that WMA affected the pore structure and new calcium-based products were formed along with polymeric products. New products in the matrix accelerate the polymerisation process and significantly enhanced the strength properties and durability of AAC. The outcomes of this study revealed that WMA can be employed to replace up to 50% of NA in the production of sustainable AAC. Its high potential to replace NA could lead to significant saving in energy, cost and, can further reduce the hazardous environmental impacts caused by marble industries during mining, processing and polishing phases. [ABSTRACT FROM AUTHOR]

• Ultrafine slag enhanced the mechanical properties of the geopolymer concrete. • Corn con ash improved the durability of the sustainable geopolymer concrete. • Pore structure can be improved by incorporating CCA. • Reduced drying shrinkage was obtained for RHA and CCA based geopolymer concrete. This paper presents the first scientific attempt to develop and study the performance of rice husk ash (RHA) and ultra-fine slag (UFS) based sustainable geopolymer concrete with different ratio of corn cob ash (CCA). NaOH (8 M) and Na 2 SiO 3 were employed as alkaline activators. CCA acted mainly as amorphous silica and was utilised as a substitute for RHA. The effects of different CCA contents (0%, 3%, 6%, 9% and 12% by RHA mass) on the performance of geopolymer concrete in terms of fresh, hardened and durability properties have been evaluated. Different characteristics, i.e. density, air content, workability, compressive, flexural and split tensile strengths, Young's modulus of elasticity were investigated. Meanwhile, the durability performance was also evaluated by using different methods such as rapid chloride penetration test, chloride conductivity test, water sorptivity test and DIN (Deutsches Institut für Normung) water permeability test. The outcomes of this research have shown that UFS and CCA improved the compressive strength by 14–15%. They significantly improved the polymerisation and thus enhanced the strength and durability of sustainable geopolymer concrete. Furthermore, CCA and UFS acted as micro fillers and increased the CaO as well as SiO 2 contents which enhanced the densification. Additionally, the development of hydration products in the matrix, enhanced the pore structure and thus the strength. This study revealed that CCA (up to 6%) can be utilised as a substitute binder to produce sustainable geopolymer concrete, and has the potential to replace conventional concrete for structural applications. [ABSTRACT FROM AUTHOR]