Abstract: thermal resistance, thermal cracking, water absorption, strength

Abstract: This article is especially regarding the review of Feasibility of Manufacturing of Clay Tiles Using Clay of soils and under the introduction, importance of clay roof tiles comparing with asbestos sheet, cement roof tiles and other roof materials., physical and chemical factors that affect the behaviour of thermal insulation, thermal resistance, thermal cracking, water absorption, strength and life span, manufacturing method according Sri Lanka standard specification for clay roof tiles (1975 SLS) and what physical and chemical properties should be in clay which are being researching to find proper solution or develop any properties of clay, testes and significance of the study were mentioned. Under the background, there were reviewed some research articles which has suggested some solution for this research.In Sri Lanka, the most common roofing materials use are clay tiles, asbestos sheets and cement tiles. But cement tiles is more costly and asbestos sheet has some health risk. At present, asbestos sheet has banned by government. Usually clay tile is costly material to build roof construction and usually clay is somewhere in Sri Lanka. So we have to find method to as roofing materialKeywords: clay extract from soil; clay tiles; easy method to manufacturing; cool roofs; economically.1. IntroductionRoof is one of the important and appearance part of the houses and other buildings. In Sri Lanka, the most common roofing materials use are clay tiles, asbestos sheets and cement tiles. Earlier days most of the roof built by clay roof tiles, but nowadays roof are built by asbestos sheets and cement tileseven though those are not better than clay tiles, because it has some properties better than other material such as good thermal insulation, high fire resistance, long lifespan, UV-resistance, durable colour and good appearance.Roughly the roof cost will be 10-15% of the total cost, thus peoples most use asbestos sheets. Because low cost, high roof covering, quick construction and good strength, but recently asbestos sheet has some health risk, so it is banned by government. World Health Organization has said that all type of asbestos sheet cause lung cancer, mesothelioma, cancer of the larynx and ovary, and asbestosis. But asbestos is a cheaper than other roofing materials and also can be constructed quickly, no need to more timber bars, no more labours and it has good strength better than clay roof tiles. At present, peoples who willing to use metal roofing sheet as roofing material, because peoples mostly like material as economically. But that roofing material has low thermal insulation, low thermal resistance and less lifespan. Thus it is not more suitable for roof of house. And available of clay not everywhere in Sri Lanka. So we have to find other method to roof material with friendly of environment and economically.2. BackgroundRoof is one of the important and appearance part of the houses and other buildings. Roughly the roof cost will be 10-15% of the total cost (cost modelling for roofing material selection). In Sri Lanka, the most common roofing materials use are sheets and cement tiles (ICTAD specification for building works, 2011). Earlier days most of the roof built by clay roof tiles, but nowadays roof are built by asbestos sheets and cement tiles even though those are not better than clay tiles, Peoples most use asbestos sheets. Because low cost, high roof covering, quick construction and good strength (Design guidelines for timber celling structure with asbestos sheet, 2004), but recently asbestos sheet has some health risk, so it is banned by government. World Health Organization has said that all type of asbestos sheet cause lung cancer, mesothelioma, cancer of the larynx and ovary, and asbestosis (Asbestos Exposure and Cancer Risk Fact Sheet – National Cancer, 2016). But asbestos is a cheaper than other roofing materials and also can be constructed quickly, no need to more timber bars, no more labours and it has good strength better than clay roof tiles.The Sri Lanka Environment Protection Agency (EPA) is proposing that all major sources in Tiles and Clay products manufacturing category meet health-based standards for acid gas hazardous, air pollution, maximum achievable control technology standards for mercury, non-mercury metal hazardous air pollutants, and dioxins/furans, work practise standards, where applicable. The proposed rules would protect air quality and promote public health by reducing emissions of the hazardous air pollutants listed of the clean air act (Roofing materials assessment investigation, 2016). When it is reused as a construction material, it is typically employed as a raw material in cement or an aggregate in concrete. Analysed the physical and chemical properties of clay and measured its leachate characteristics using various testing techniques, pointing out that clay can be used to produce back filling material, soil amendments, flow able fills, and embankments. The use of reused method helps to reduce waste disposal problems.Here clay take from extract the soil, so we have to find a method for extraction. There are some soil washing machine for separation the soil particles. But it is not more suitable for extract clay from soil (Soil-washing technology and practice, 1995). We have to collect suitable soil through the experimental. If that clay has not have suitable properties, we have to change properties of that clay. The effect of global warming change are of relevant environment and human activities in the urban and rural area. The houses and other building area is effect by summer and winter, so the good roof material should be product the buildings from that summer and winter. Thus clay material should be contain suitable thermal insulation, thermal resistance and cooling system (Summer and winter effect of innovative cool roof tiles, 2014).The conventional method of tiles production has brought undeniable shortcomings. The consumption of earth-based materials as clay, shale and sand in tiles production resulted in resource depletion, environmental degradation, and energy consumption. Main resources are mined from riverbeds and hillsides to service usually clay tilesindustry leaving mines areas un-reclaimed. Environmental degradation accompanies such mining activities with air pollution and remains after the mines cease operations, leaves scars on the landscape.Clay has some chemical properties and physical properties, thus thing is suitable for manufacturing tiles and bricks. So we have to analysis such properties to extract clay from soil, such properties are plasticity index, liquid limit, chemical compositions and particle size distribution(Properties of clay, 1985) (Physical properties of clay and soil mechanics, 2013). Particles size distribution test method covers the quantitative determination of the distribution of particle size of the fine grained portion of soils. The sedimentation or hydrometer method is used to determine of the material that is finer than the 0.075mm sieve and larger than about 0.0002mm (Soil particle size analysis test, 1981). The test is performed on materials passing the 2mm sieve or finer sieve and the results are presented as the mass percent finer versus the log of the particle diameter.The plasticity index (PI) is a measure of the plasticity of a clay soil. The plasticity index is the size of the range of water contents where the soil exhibits plastic properties. The PI is the difference between the liquid limit and the plastic limit (Determination of plasticity index of clay, 2012). The liquid limit is conceptually define as the water content at the behaviour of clay soils changes from plastic to liquid. Here we done by Atterberg apparatus. Shrinkage limit is the water content where further loss of moisture will not result any more volume reduction. The test to determine the