In this paper, the use and effect of Ground Granulated Blast Furnace Slag (GGBFS) addition to fly ash (FA) on the performance of Geopolymer Concrete was presented. A reference of Ordinary Portland cement concrete (OPC) mix was used to compare with geopolymer concrete. The effect of different proportions of GGBFS addition, ambient curing, and curing age on the properties of geopolymer concrete was reported. The concentration of sodium hydroxide solution with 8 M and solution to binder ratio as 0.4 were taken for all the mixes of geopolymer concrete. This paper reported an investigation data on the mechanical and durability characteristics of fly ash-GGBFS based geopolymer concrete and that data was compared with the control mix (OPC). SEM analysis was done on selected samples to estimate the microstructural characteristics. The results concluded that a geopolymer concrete mix containing 60% GGBFS and 40% fly ash at 28 days of ambient temperature achieved maximum compressive strength (55.63 MPa) and further performed durable under severe environmental conditions.

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Strengthening of reinforced concrete structures is given top priority in construction sector across the world. Ageing and load pattern changes will affect the stability of structure may be reduced. In this case, Fibre-Reinforced Polymer (FRP) materials are recognized as vital constituents to solve stability issues of the modern concrete structures. The purpose of present constructive studies of various techniques for FRP retrofit concrete structures because, the FRP material has improves the structural performance in terms of stability, stiffness, strength and durability such that the Fibre-Reinforced Polymers wrapping is one of the techniques to regain the strength of a concrete structures. By various researchers the different wrappings techniques are used to regain the strength and also enhanced the durability of the structure. This paper focuses mainly on various wrapping techniques of FRP sheets for external strengthening of RC structures such as reinforced circular columns, square beams, columns and column-beam joints.

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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.