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Utilization of waste materials and byproducts is a partial solution to environmental and ecological problems. Use of these materials not only helps in getting them utilized in cement, concrete and other construction materials, it helps in reducing the cost of cement and concrete manufacturing, but also has numerous indirect benefits such as reduction in landfill cost, saving in energy, and protecting the environment from possible pollution effects. Electronic waste, abbreviated as e-waste, consists of discarded old computers, TVs, refrigerators, radios - basically any electrical or electronic appliance that has reached its end of life. Efforts have been made in the concrete industry to use non biodegradable components of E waste as a partial replacement of the coarse or fine aggregates. With the increasing use of automobiles, more and more scrap tyres have to be discarded, and this has become an environmental issue all over the world. For example, around 285 million tyres are discarded annually in the USA alone, and only 34% of them are being used or recycled. As rubbers are not biodegradable and will remain in a landfill without any degradation for a very long time, their accumulation may provoke fire or health hazards and cause troublesome environmental problems. A possible solution to the problem is to incorporate the shredded rubbers into concrete. Moreover, the use of rubber tyres in concrete could provide a permanent disposal of this waste material. Therefore, successful use of the material in concrete could not only provide a promising solution to the environmental problems. but also afford a material with some desirable properties Fine aggregate is an essential component of concrete. The most commonly used fine aggregate is natural river sand. The global consumption of natural river sand is very high due to the extensive use of concrete. In particular, the demand of natural river sand is quite high in developed countries owing to infrastructural growth. The non-availability of sufficient quantity of ordinary river sand for making cement concrete is affecting the growth of construction industry in many parts of the country. Recently, On the other hand, the granite waste generated by the industry has accumulated over years. Only insignificant quantities have been utilized and the rest has been dumped unscrupulously resulting in environment problem. With the enormous increase in the quantity of waste needing disposal, acute shortage of dumping sites, sharp increase in the transportation and dumping costs affecting the environment, prevents the sustainable development. The waste disposal problem is becoming serious. A possible solution to the problem is to incorporate the granite powder as replacement of sand and partial replacement of cement with fly ash, silica fume, slag and superplasticiser in concrete. Naturally occurring decomposed granite is generally found as a by-product from quarries in Australia and around the world. It is currently used in applications such as, backfill, sub-grade, driveways and landscaping. A possible solution to the problem is to incorrect it into correct. Marble has been commonly used as a building material since the ancient times. The industry's disposal of the marble powder material, consisting of very fine powder, today constitutes one of the environmental problems around the world (Corinaldesi et al., 2010). Marble blocks are cut into smaller blocks in order to give them the desired smooth shape. During the cutting process about 25% the original marble mass is lost in the form of dust. marble dust is settled by sedimentation and then dumped away which results in environmental pollution, in addition to forming dust in summer and threatening both agriculture and public health. Many studies have been conducted in literature on the performance of the concrete containing waste marble dust or waste marble aggregate, such as its addition into self compacting concrete as an admixture or sand (Corinaldesi et al., 2010; Alyamac and Ince, 2009; Guneyisi et al., 2009; Unal and Uygunoglu, 2003), as well as its utilization in the mixture of asphaltic concrete (Karasahin and Terzi, 2007; Akbulut and Gurer, 2007; Binici et al., 2008) and its utilization as an additive in cement production (Aruntas et al., 2010), the usage of marble as a coarse aggregate (Wu et al., 2001) and as a fine aggregate passing through 1 mm sieve. Glass from varying recycling processes is considered to be a material which could be used as binder and also as aggregate replacement. Glass which is most considered for recycling in terms of environmental protection is that from containers, architectural and end of life vehicle glass. During the last decades it has been recognized that Sheet Glass waste is of large volume and is increasing year by year in the Shops, construction areas and factories. The most widely used fine aggregate for the making of concrete is the natural sand mined from the riverbeds. However, the availability of river sand for the preparation of concrete is becoming scarce due to the excessive nonscientific methods of mining from the riverbeds, lowering of water table, sinking of the bridge piers, etc. are becoming common treats . The present scenario demands identification of substitute materials for the river sand for making concrete. it is possible to manufacture concrete containing Sheet glass powder (SGP) with characteristics similar to those of natural sand aggregate concrete provided that the percentage of SGP as fine aggregate is limited to 10-20%, respectively. Slates are regionally metamorphosed argillaceous rocks. These are found in nature in both thinly and thickly bedded formations with slightly undulating surfaces and well-developed cleavage planes. It is a low value mineral, which is used principally as roof tiles in buildings or as writing pads. These are being mined at a number of places in India and distributed through dealer networks all over India. The extraction of slate generates huge amounts of waste. As much as 50% of the material is wasted during the extraction, cutting and dressing operations. The site, where slate waste generation took place has a hilly topography and due to this, there is a limited availability of space for waste storage and movement of man and material. This has resulted into the dumping of waste all along the hill slopes causing environmental hazards and an eyesore. Excessive generation of slate and its progressive accumulation over hundred of years of exploitation has resulted in the destruction of the ecology of the region. the slate waste can be used in the preparation of concrete blocks for application in building construction. These blocks will be cheaper and economically viable for use in hills where conventional bricks are in short supply.
Preliminary results of a study conducted by Achaean et al. (1998) suggest that the addition of rubber shreds to mortar reduced plastic shrinkage cracking compared to a control mortar. The use of rubber shreds in mortar allowed multiple cracking to occur over the width of mortar specimens compared to a single crack in a mortar specimen without rubber shreds. In spite of the occurrence of multiple cracking, the total crack area in the case of the rubber-filled mortar decreased with an increase in the rubber mass fraction. Despite their apparently weak bonding to the cement paste, rubber shreds provided sufficient restraint to prevent micro cracks from NEHDI AND KHAN ON RECYCLED TIRE RUBBER 5 propagating. It was observed (Raghaven et al. 1998) that the control mortar specimen developed a crack having an average width of about 0.9 mm, while the average crack width for specimens with a mass fraction of 5% rubber shreds was about 0.4 to 0.6 mm. It was also found that the onset time of cracking was delayed by the addition of rubber shreds; the mortar without rubber shreds cracked within 30 min, while the mortar with a mass fraction of 15% rubber shreds cracked after 1 h. The higher the content of rubber shreds, the smaller the crack length and crack width, and the more the onset time of cracking was delayed. Although additional studies are necessary to confirm these observations, it appears that the addition of rubber shreds could be beneficial for reducing plastic shrinkage cracks of mortar and probably of concrete.
The Flexural strength test results for the curing concretes with SGP of different percentage according to their age are presented in Fig. (9). The results were very similar to each other like compressive and tensile strength test results. The concrete containing SGP as fine aggregate, at a 10-20% mixing ratio, showed a slight increase in the flexural strength while that of plain concrete. At 30%, 40%, 50% and 100% mixing ratio there was increase in strength than that of plain concrete. The compressive strength of cubes and cylinders of the concrete for all mix increases as the % of SGP increases but decreases as the age of curing increases due to alkali silica reaction. The Tensile strength of cubes and cylinders of the concrete for all mix increases than that of conventional concrete age of curing and decreases as the SGP content increases. The Flexural strength of the beam of concrete for all mix increases with age of curing and decreases as the SGP content increases. 100% replacement of SGP in concrete showed better results than that of conventional concrete at 28 days and 45 days curing but later it started to decrease its strength because of its alkali silica reactions. The optimum replacement level in fine aggregate with SGP is 10%.
This study intended to find the effective ways to reutilize the various waste as concrete aggregate. It is identified that e-waste can be disposed by using them as construction materials. 20% of E-waste aggregate can be incorporated as coarse aggregate replacement in concrete without any long term detrimental effects with acceptable strength development properties. Investigation suggests that replacing some of fine aggregate in concrete by rubber tyre particles may be suitable in applications such as driveways, sidewalks, or in road constructions where strength is not a high priority but higher toughness is preferred. Rubberized concrete is also suitable where structure vibration control is required, such as in structural base isolation and machine foundations. Investigation suggest that decomposed granite appears to be suitable for use in concrete with a characteristics strength of 25MPa. The SGP is suitable for concrete making. The optimum replacement level in fine aggregate with SGP is 10%. The slate mine waste can be used in the preparation of concrete blocks for application in building construction.