Effect of Bogue Potential Phases of Clinker on the Mechanical Strength of Fly ash-Limestone Based Portland Composite Cement

Abstract

Continuous rise in population coupled with infrastructural requirements leads to increasing demand of cement which is projected to be around 4.8 billion tons by 2030 and 6.0 billion tons annually by 2050 from current production level of more than 4.2 billion tons [1], and this further requires judicious use of natural resources, particularly limestone on one side and to mitigate carbon and energy footprints on other for sustainable development. Therefore, to bring down environmental impact during cement production, cement industries have been engaged over the years to substitute Portland cement with alternative cementitious materials; fly ash, granulated blast furnace slag, limestone etc individually or in combination of two-three mineral constituents in the manufacture of blended cements, which showed better durability characteristics in comparison to ordinary Portland cement. The formulation and commercialisation of these cements largely depends on the quality of Portland clinkers in terms of oxide constituents, potential as well as actual phase composition, morphology and granulometry of alite and belite grains, along with availability and quality of the cementing materials, prevalent standard norms and regulations. In view of above, present paper highlights the effect of different clinkers in terms of potential minerals as per Bogue calculations (CL-1:C3S-48.20%, C3A-6.30%; CL-2:C3S-54.20%, C3A-9.30% and CL-3: C3S-60.05%, C3A-9.0%) on mechanical strength of fly ash-limestone based ternary cement blends, Portland composite cements, similar to CEM-II/A, B-M as per EN-197-1, prepared with 15, 20, 25, 30 and 35% by weight fly ash and 5 & 10% by weight limestone, by inter-grinding of all cement constituents process, maintaining Blaine’s fineness at 370±10m2/kg, and the results of compressive strength at different curing ages showed optimum strength development in case of clinker CL-2 with potential phases, C3S-54.20% and C3A-9.30%, thus leading to better management of natural resources and extended mine life.