Browsing by Author "Udayashankar, B.C."

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    Effect of Water Content on Relative Flow Area and Hence Predicted Flow Values of Controlled Low Strength Materials
    (American Society of Civil Engineers (ASCE), 2018) Raghavendra, T.; Udayashankar, B.C.; Lokeshwari, M.; Shelar, M.; Amaranath Reddy, N.
    Urban cities are embracing new innovations in built-up spaces and thereby necessitating renovations or constructions for new buildings either by demolition of obsolete buildings or at new places to expand the city itself. In this regard natural stones are converted to aggregates and hence generate stone dust as a waste. Construction and demolition wastes include brickbats which are used as in-fills. Many attempts have been made to re-use these wastes but still the problem persists and large percentages of these wastes reach landfills. Controlled low strength materials (CLSM) are an obvious choice for use of these wastes in large quantities, required for sustainable city objectives. CLSM is a cementitious and self-flowing backfill material. Design of CLSM mixes involves iteration process mainly to satisfy the flow and strength requirements. Phenomenological models are an effective tool in the design of CLSM mixtures with a single trial. In this paper Class F fly ash was used as secondary cementitious material along with powdered brickbats, stone dust as fine aggregates in complete replacement to natural sand; to produce sustainable CLSM mixtures with varying Class F fly ash to cement ratios and water contents. Spread flow and marsh cone flow tests were conducted on fresh CLSM mixtures and compressive strength tests were carried out on hardened cylindrical specimens at 3, 7, 28, and 56 day age. Spread flow values were converted to relative flow area values. Phenomenological models (flow and strength) were generated using wide range of experimental data to predict flow and strength values. The water demand of quarry dust mixes was more compared to brickbats mixes and this resulted in lesser flow values and hence non-flow results. Incorporation of these non-flow values in the generation of flow prediction models resulted in poor prediction of flow results; however strength prediction was not influenced. Discarded brick bats and quarry dust are hence recommended for use as fine aggregates along with Class F fly ash as secondary cementitious material in CLSM to overcome urbanization challenge for sustainable development. © 2018 American Society of Civil Engineers.
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    Urbanization Challenges in Emerging Economies
    (American Society of Civil Engineers (ASCE) onlinejls@asce.org, 2017) Lokeshwari, M.; Mendi, V.; Raghavendra, T.; Reddy, A.; Udayashankar, B.C.
    Rapid urbanization, industrialization, and change of life style of people has increased the rate of solid waste generation by leaps and bounds in the developing countries. Municipal solid waste generation varies with place to place and the standard of living of the people residing in cities. Solid waste consists of organic matter, which undergoes degradation and produces foul smell, if not properly managed. Therefore management of the garbage had reached a very critical stage and now emphasis has been given to its collection, treatment, and final disposal. Generally in Indian cities, waste is collected and simply dumped outside the cities which are called as landfill sites. Any method of disposal other than composting will be uneconomical, required skilled person, and also pollute air, water, and soil. Large quantity of plant nutrients gets wasted in other methods of disposal. Composting is not a method of waste disposal but it is a method of recycling the waste. Municipal solid waste is one of the potential organic nutrient residues, which upon recycling leads to a valuable compost, which is vital for growth and development of plants. Sewage sludge is rich in micro-organisms, organic content, as well as nutrient elements. So in this study co-composting of municipal waste with sewage sludge has been taken up to conserve nutrients. In the present work studies were conducted on municipal solid waste, mixed with sewage sludge in different proportion, to check the technical viability of the integrated system of composting. Addition of sewage sludge to waste for composting not only increases decomposition rate and fertility value, it also solve the problem of sludge disposal from treatment plant. It will save the cost of sludge treatment. Municipal waste compost can be regarded as being valuable in soil management practices because of their organic matter content. © 2018 American Society of Civil Engineers.