Please solve as soon as possible The cement and concrete industry is a key link in...

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Civil Engineering

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The cement and concrete industry is a key link in the circulareconomy. Alternative fuels/raw materials in cement kilns, utilisingrecycled aggregates and cementitious industrial by-products inconcrete and producing durable concrete structures assist in thecircular economy. Example of fly ash production is shown in Figure1. Discuss the use of any THREE new binders, waste materials andrecycled materials (as ingredients) in concrete production andtheir suitable applications. Produce a ‘white paper’ (not more than5 pages) and it should include the following:
(i) Identified 3 ingredients and a brief description of theirproduction.
(ii) How these materials are used to produce certain grades ofconcrete.
(iii) Energy savings and carbon dioxide emissions of allingredients.
(iv) Link with circular economy.

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Sol Management and treatment of industrial solid waste and municipal waste has been gaining importance Waste material can be utilized as fuel in cement kilns as raw material for cement clinker as mineral addition to cement or as granular material in cement mortar and concrete Depending on the properties of the waste it can be used in the cement and concrete industry without treatment or after treatment Although vast amounts of waste material can be consumed in the production of cement clinker and blended cement that consumption can be increased substantially if it is used as aggregate in cement mortar and concrete Using waste material in this way can solve problems of shortage of aggregate in construction sites and reduce environmental problems related to aggregate mining and waste disposal For effective use of waste in the construction industry a combined chemical civil material and environmental engineering approach is necessary Careful characterization of waste is necessary before it is used in construction Treatment of some waste materials is necessary to improve their quality before being incorporated into concrete Environmental assessment of waste and concrete containing waste is also necessary for proper evaluation of waste materials as a constituent in concrete Slump bulk density unit weight and air content mechanical properties such as strength and elasticity modulus and durability properties such as water absorption shrinkage carbonation and chloride resistance of fresh and hardened concrete containing waste materials are normally evaluated Some waste materials can improve certain concrete properties such as fire behaviour thermal insulation and cracking and therefore some reports are available on these topics too But the durability performance of concrete containing waste materials has not been evaluated to the same extent and therefore significant research is necessary on this topic As different waste materials can change themicrostructure of mortar and concrete and the hydration chemistry of cement more work is necessary to understand the aggregatecement interaction in concrete and to develop more robust waste aggregatebased concrete technology 1 USE OF PLASTIC WASTE IN CONCRETE Huge amounts of plastic solid waste are generated all over the world by the consumption of packaged products Dumping plastic waste in landfills is not possible due to its slow degradation rate and bulky nature The high calorific value of plastic waste can be used for incineration or other high temperature processes but their combustion produces dangerous gases that could be harmful to human health Although these alternatives are feasible recycling waste plastic to produce new materials such as concrete appears to be the best solution for disposing of it since it is both cheaper and has ecological advantages The incorporation of plastic in the form of aggregate or fiber lowers the slump value of fresh concrete because of the sharp edges and angular particle size of plastic aggregate However an increase in slump value due to incorporation of this material has also been reported Concrete mixes containing plastic aggregates will have more free water as plastic aggregates neither absorb nor add any water to the concrete mix and therefore this increases slump The incorporation of plastic as aggregate decreases the modulus of elasticity and the compressive splittingtensile and flexural strengths of the resulting concrete The factors that may be responsible for low compressive and flexural strength of concrete containing plastic are 1 the decrease in bond strength between the surface of the plastic waste and the cement paste 2 the hydrophobic nature of plastic waste which can inhibit cement hydration reaction by restricting water movement In a recent study it was found that the incorporation of plastic up to a certain level did not influence the compressive and flexural strength of concrete However curing conditions were slightly different from those of the majority of the other studies and that might have had some effect on the properties Concrete containing waste plastic showed no propagation of micro cracks and improved toughness compared with conventional concrete However toughness indices of concrete containing PET fiber decrease with longer curing time due to degradation of the fiber by alkaline hydrolysis The incorporation of plastic aggregate in plain concrete improves thermal insulation performance which is dependent on the shape of the plastic aggregate too So we can say that waste plastics can be used as replacement for fine aggregates in concrete for the production of lightweight concrete Addition of granulated waste plastics effectsthe compressive strength and density of concrete Portland cement was mixed with the aggregates to produce the concrete composites Grade 20 concrete design strength of mix ratio 1 23 35 and 065 wc ratio was used for the experiment Five weight fractions 0 5 10 15 20 and 30 of granular plastic waste were used to replace the fine aggregate in the batchingIn this way we high compressive strength concrete is produced Cement manufacturing is highly energy and See Answer

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