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The carbon dioxide produced by cement industries causes environmental pollution and global warming. In 1000 Kg of cement manufacturing processes, approximately 900 Kg of CO2 is emitted. In order to reduce the impact of cement production on atmosphere, waste bi-products are used as admixture. In India, every year 75 million tons of fly ash, which are rich in silica, are disposed to landfill as waste. Also, Egg Shell Powders (ESP), which are rich in calcium, are thrown away as waste. In the paper, these two wastes are used as a partial replacement of cement, and various properties like workability, compressive strength, split tensile strength and flexural strength are studied. ESP was varied up to 15.0% (0%, 2.5%, 5%, 7.5%, 10%, 12.5% and 15%) and fly ash was added to cement from 0% to 30% (0%, 5%, 10%, 15%, 20%, 25% and 30%). The results further showed that addition of fly ash along with ESP is beneficial for improved performance of concretes. [ABSTRACT FROM AUTHOR]

Policy makers in India have realized the importance of facility for pedestrians and non- motorized vehicles in an urban infrastructure setup. This has resulted in increased utilization of construction materials like Portland cement and crushed stone, which are not environmentally friendly and sustainable. The current study presents the development of paver blocks for pedestrian facility using different wastes. Geopolymer concrete was synthesized by fly ash and recycled asphalt pavement aggregates for making of paver blocks. Paver blocks were produced in laboratory with recycled asphalt pavement aggregate replacement levels of 0%, 20%, 40%, 60% and 80% by weight of virgin coarse and fine aggregates. The developed paver blocks were tested for dimensions and tolerances, water absorption, compressive strength and abrasion resistance as per IS15658:2006 standard. The results of the laboratory study show that recycled asphalt pavement aggregates can be introduced into geopolymer matrix to produce paver blocks of desirable quality. Furthermore, its use in pedestrian facilities provides a new avenue for managing the excessive waste, which otherwise goes in landfills, incurring loss to the paving industry. Therefore, the proposed method can help decision makers to effectively utilize recycled asphalt pavement in paving industry with environment-friendly approach. [ABSTRACT FROM AUTHOR]

The knowledge about the utility of fly ash is well known worldwide. Moreover, even though fly ash is widely and abundantly available in India, its optimal utilization is not yet achieved. This paper attempts to give clarity on the viable limit of fly ash in structural concrete. The study confirms the applicability of efficiency factor method in the mix design and strength prediction of concrete. Maximum usable fly ash percentage depends upon the strength of concrete and type of chemical admixture. Although the results presented herein may vary with change of constituent materials, type of concrete, type and power of concrete mixer, ... etc., the trend in results would remain similar and will be useful for both researchers and practicing engineers in concrete technology domain striving for sustainable construction. [ABSTRACT FROM AUTHOR]