Durability and flexural behaviour of fly ash based geopolymer concrete beams

Abstract

The production of Portland cement has been swelling manifold newlinethroughout the world due to the mounting demands of the construction newlineindustry. However, this huge production of Portland cement is highly internalenergy- newlineintensive and causes emission of green house gas, CO2. The pollution newlineinvolved in the manufacture of cement hampers the image of concrete as a newlinesustainable material. Efforts are continuously being made to make concrete newlineenvironmentally friendly. Concrete is the most commonly used construction newlinematerial without proper substitute so far. With the increase in construction newlineactivities, there is heavy demand on its ingredients, particularly for cement. newlineMany such alternates for cement have been tried by different scientists newlineworldwide, but the best choice of a substitute material to cement has been newlineagreed to be the Geopolymer paste. Also, cement is manufactured by the newlinecalcination process of a hefty quantity of lime stone and this large quantity of newlinelime stone is explored from the lime quarries, which in turn creates an newlineimbalance in the mineral wealth of our planet. newlineIn spite of the easy availability of Portland cement in the market at newlinepresent, concrete made out of it is found to be less durable in some of the very newlinesevere environmental conditions due to the presence of free calcium. newlineTherefore, arrival of any new alternate material of construction immediately newlineshould be assessed for both strength and durability. The complex newlinephenomenon of aggressive chemical attack and the associated damage to newlineconcrete considerably reduces the strength and stiffness of reinforced concrete newlinemembers leading to premature failure. Failure does not only mean structural newlinecollapse but also includes loss of serviceability characterized by cracking, newlinespalling, debonding or excessive deflection. newlineKeeping all the above aspects in mind, a detailed experimental newlineinvestigation on the manufacturing process, serviceability under loads, newlinedurability against various severe disturbing agents are inevitable as far as a newlinenew material is concerned. newline