Alkali-activated slag concretes are being extensively researched because of its potential sustainability-related benefits.\nFor such concretes to be implemented in large scale concrete applications such as infrastructural and building elements, it is\nessential to understand its early and long-term performance characteristics vis-a-vis conventional ordinary portland cement (OPC)\nbased concretes. This paper presents a comprehensive study of the property and performance features including early-age\nisothermal calorimetric response, compressive strength development with time, microstructural features such as the pore volume\nand representative pore size, and accelerated chloride transport resistance of OPC and alkali-activated binder systems. Slag\nmixtures activated using sodium silicate solution (SiO2-to-Na2O ratio or Ms of 1ââ?¬â??2) to provide a total alkalinity of 0.05 (Na2O-tobinder\nratio) are compared with OPC mixtures with and without partial cement replacement with Class F fly ash (20 % by mass) or\nsilica fume (6 % by mass). Major similarities are noted between these binder systems for: (1) calorimetric response with respect to\nthe presence of features even though the locations and peaks vary based on Ms, (2) compressive strength and its development, (3)\ntotal porosity and pore size, and (4) rapid chloride permeability and non-steady state migration coefficients. Moreover, electrical\nimpedance based circuit models are used to bring out the microstructural features (resistance of the connected pores, and\ncapacitances of the solid phase and pore-solid interface) that are similar in conventional OPC and alkali-activated slag concretes.\nThis study thus demonstrates that performance-equivalent alkali-activated slag systems that are more sustainable from energy and\nenvironmental standpoints can be proportioned.
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