Digital Repository, University of Moratuwa

    Evaluation of shear design procedures adopted in the industry for reinforced concrete

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    Reinforced Concrete is a construction material used for nearly one and a half centuries. It has become a popular and widely accepted practice in the industry. From the design point of view, concrete members subjected to flexure can be designed to a very high degree of accuracy, but shear design procedures are not well established and are not clear. Several theories have been put forward but none of them seem to have resolved the issues.Senate Research Committe

    Development of a landfill clay liner using locally available expansive soil

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    Solid waste is a growing problem in urban areas of Sri Lanka and management of waste, both liquid and solid has become a critical environmental concern due to absence of engineered methods of disposing waste. Development of a simple engineered landfill facility utilizing locally available materials to suit landfill liner requirements is the most economical and the timely solution to this problem. In the present study, it was investigated the suitability of expansive soil which is commonly available in the south arid zone of Sri Lanka to use as clay liners in landfill facilities. The engineering properties of soil were improved by the addition of commercially available bentonite to build a low hydraulic conductivity barrier. Further, the long term effect of soil-leachate interaction on hydraulic conductivity of the suggested liner was studied. Results showed that the engineering properties of expansive soil can be improved by the addition of bentonite to meet the landfill liner requirements. However, the original engineering properties of soil-bentonite mixtures were significantly affected by the leachate interaction over a long period of time

    Study the effect of waste rubber materials on shear strength of residual soils

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    One of the problems associated with the socio-economic development of Sri Lanka is waste disposal. One of the wastes generated in engineering and transportation sector is scrap tire and it poses serious environmental problem, worst when it is burnt. This Paper presents study the effect of waste rubber materials on shear strength of residual soils. Series of laboratory direct shear tests were carried out on soil reinforced with randomly distributed rubber strips. The soil was collected from the university premises and rubber strips were obtained from scraped tire tubes. 20mm × 5mm tire tube strip sizes were used as the reinforcement of the residual soil and 0%, 0.5%, 1.0%, 1.5%, 2.0%, 2.5%, 3.0% increments were used until reached to the optimum rubber percentage. According to the tests results, the soil type was identified as CVG according to the BS 5930 1990 and the optimum rubber content is 2.0% for the maximum shear strength

    Study effect of polyester fibres on engineering and durability properties of high volume fly ash concrete

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    Need and Growth of infrastructural facilities has been tremendously increased during last two decades across the world and hence the construction industry. In construction industry concrete of various kinds is the key material because of its potential benefits, low inherent energy and recycle values. On the earth concrete is the most consumed material after water; which needs to give due consideration towards the sustainability of concrete industries in particular. The sustainability issue for concrete construction industry is not arrived due to one or more reasons related to the material or the technology itself. This includes it consumes large quantities of virgin materials; the principal binder in concrete is cement, a major contributor to greenhouse gas emissions that are implicated in global warming and climate change. Cement on other hand also utilizes natural resource in form of lime stone. Huge amount of energy is consumed in mining, blasting, crushing and transportation of these raw materials. Concrete structures suffer from durability issues which have an adverse effect on the resource productivity of the industry. Potential and optimize utilization of cementing material in concrete will definitely lead towards sustainable concrete construction. Use of industry waste and by products like fly ash, silica fume, grounded granular slag to partly replace cementing material to concrete system addresses all three sustainability issues, its adoption will enable the concrete construction industry to become more sustainable. High Volume Fly Ash (HVFA) concrete is one of the solutions in this context of sustainable concrete construction. Though HVFA concrete technology has been developed way back and being proven technology for construction industries with potential benefits over regular concrete, it has been not become popular in developing countries due to one or other limitations like ductility, impact and abrasion resistance. Authors in this article will describe effect of polyester fibres on engineering properties Impact Strength and Abrasion Resistance of High Volume Fly Ash Concrete design mix M25, M30, M35 and M40. Test samples include replacement of cement by 50%, 55% and 60% class F fly ash. Paper contains test results of key material like fly ash, fibre, mix design for all grade, 60 min. slump comparison, comparative study of impact and abrasion resistance for plain and fibre reinforced HVFA at 28 and 56 days age. Comparative studies of economic gain with HVFA over conventional mix will also be presented to address sustainability issue

    Zinc adsorption by lowcost sorbent materials: clay tile, Brick, sawdust and rice husk

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    It has been found over the past couple of years rapid growth of population, industrialization and urbanization has first and foremost contributed to the severe water pollution in both surface and ground water. The health hazards associated with heavy metals have been on the rise, particularly the chronic diseases. Lack of tertiary treatment of wastewater may have contributed to this emergent problem, adsorption process is considered as the best available water treatment method and activated carbon has proven to be the best sorbent material which can be used in removing wide variety of pollutants. However, usage of this activated carbon becomes restrict due to its high cost and regeneration cost. Therefore, the present study focuses on low-cost sorbent materials: viz., clay tile, brick, sawdust and rice husks. Laboratory-scale experiments were performed with a synthetic Zinc solution. Results revealed that clay tile material has the highest adsorption capacity (47.6 mg/g) and removal efficiency, (98%), while brick (37.0 mg/g, 86%), sawdust (20.4 mg/g, 80%) and rice husks (15.8 mg/g, 64%) have relatively low adsorption capacities and removal efficiencies, respectively. The separation factor of equilibrium (RL) indicates favourable isotherms (0< RL<1) for all tested sorbent materials. Among the studied materials clay tile, brick and rice husks are good adsorbent for Zinc (n>2) while sawdust is a moderately difficult material for adsorption of Zinc (n <2)

    Site- specific soil microzonation for efficient and hazard resistant site and land use planning

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    Over the years, most of the urban complexes in India have undergone a phenomenal growth for various reasons and so have their vulnerability towards different hazards. Micro zonation is thus a principal component of pre disaster mitigation effort. Unless a detailed plot level micro zonation is carried out for the city, it is not possible to prescribe detailed development guidelines and planning norms that will take into consideration the vulnerability of that land. The methodology adopted here is to analyze the results of field reconnaissance survey and soil borehole details and soil topography surveys report in the very preliminary stages of planning of town/township/institutional campuses and compare it against the priority index of various types of building that these sites constitutes in order to have the following: 1. To provide the most appropriate soil conditions to the lifeline structures. 2. from preventing the project to decelerate in doing the above.3. Reduce the negative effects of defunct urban planning in India because of outdated and ineffective development control regulations. 4. To facilitate the process of micro zonation of the cities as a whole.5. Felicitates strategic long term planning and to add to the pre-disaster mitigation efforts. 6. Help reduce the effects of construction on soil to a minimum. Urban planning framework in India has disappointingly not kept pace with the growth of cities and neither with the various changes that have come about in the way is planning understood. The Procedural that the research is trying to accomplish shall help to facilitate the process, which is indeed an urgent call in context to the disaster mitigation efforts. The process involves more of analytical work of the reports which is on general conditions available for all major projects. The ides is to put a little bit more effort and analyze them to have strategic long term plans for the towns/ townships/ institutional campuses. Therefore there shall not be much to a fiscal issue in doing so. Instead it will help to scrutinize and prevent deceleration which might occur later in the project execution. The paper shall describe in detail the relationship of soil lab tests, geotechnical test and architectural planning to achieve the above mentioned aim. Procedural will be explained giving a prototype implementation in a township development project proposed in the city of Ahmadabad, Gujarat, India (seismic zone 3, micro zone D). The information and test results for the same were obtained from Indian Seismological Institute, Gandhinagar and an Ahmadabad based soil testing company. The project falls under AUDA jurisdiction and hence the Priority index values shall be followed from its guidelines. The ultimate goal of the research is to define the principles of site specific microzonation and account the role of an Architect/ Planner in contributing towards hazard mitigation efforts and strategies

    Technology transfer to local construction industry through foreign contractors: barriers and enablers

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    Sri Lankan construction industry has developed considerably during past few years due to ongoing infrastructure development projects and post war reconstruction and rehabilitation projects. These will further trigger a construction sector boom over the next few years. Construction industry boom has invited more foreign construction firms into the local construction industry. Technology Transfer to local construction industry is one key benefit from the foreign construction firms’ involvement. Technology Transfer is a crucial and dynamic factor in social and economic development and has been transferred intentionally or unintentionally from one party to another when right conditions are provided (Li Hua and Greenwood, 2001). The development of a construction industry of a certain country can be enhanced through the involvement of foreign construction firms. However, authors’ initial investigations raised question is, whether the Sri Lankan construction industry is ready to acquire the possible construction technology through foreign firms. This paper identified enablers and barriers of Technology Transfer and suggest local construction industry to create a suitable conditions to acquire construction technology more dynamically through foreign firms
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