Sustainable Fast Setting Early Strength Self Compacting Concrete(FSESSCC) Using Metakaolin

Abstract

Sustainability in construction, using concrete as construction material, is initiated to obtain through cement, i.e. binder, optimisation and by application of secondary cementitious materials(SCMs) as component substitute of cement. The cement production industry has previously attained notable improvements in sustainability by use of byproducts of various industries as SCMs through blending suitable materials, like ferro silicon industrial by product mirco silica, steel industry by product finely ground granulated blast furnace slag, thermal power industry byproduct fly ash etc., to diminish the CO2 emission from the manufacturing plants of cement. Pozzolanicity and pore- filling qualities are the two pre requisite characteristics of the SCMs so they can play effective role in reducing the cement quantity in concrete and there by achieve sustainability. But as these quality features are inadequate in most of the industrial waste byproducts as they are not purposefully/specifically/ precisely manufactured but they are only the byproducts of industries produced as a process of manufacturing some products like steel, ferro silica alloys etc., or using some other materials like coal for producing energy. Also these SCMs are globally not obtainable everywhere. Construction industry is thus struggling with considerable cement consumption in its various activities and there by releasing enormous amounts of CO2 emissions, consumption of natural resources thereby depleting the same and increase in cost of cement production due to imposed green tax and shortage of suitable raw materials. Therefore, there is an emergent preference towards finding out various substitutive inorganic binders from native sources for partly substituting cement in concrete construction. One of the solutions to achieve sustainability in concrete construction is to use moderate reactive SCMs like flyash(FA), GGBFS(ground granulated blast furnace slag) in higher quantity and reactive SCMs like SF etc., so that demerits of slow setting and late strength gain in concrete prepared with moderate SCMs like GGBFS,fly ash etc., can be compensated by reactive SCMs,in lower quantities. Recently clays are observed to be an ample possibility as a promising reactive SCMs as they are richer in alumina and silica, and have good pozzolanic properties in definite raw, calcination situations or surface alterations forms for producing sustainable concretes with lower expenses and more eco-friendliness. In this study experimental investigation presented on the utilisation of metakaolin (MK), a high reactive SCM, in combination with GGBFS, a moderately reactive SCM, in the development of fast setting early strength sustainable self consolidating concrete(SCC) intended to use in fast track repairs/construction. Influence of MK on properties in fresh state and solidified state of SCC were studied and its effect on durability characteristics of SCC established.