Thermodynamics: What Is Soil Classification?

Soil classification is the separation of soil into classes or groups according to its similarity either characteristics or behaviour. The phrase 'Soil' come from the Latin word Solum. Different scientific fields have different meanings of the 'Soil' term. Agriculture scientist refers soil as "the loose material on earth's crust consisting of disintegrated rock with an admixture of organic matter, which supports plant life". While, Geologist distinguish soils as the disintegrated rock material which has move away from the origin place. But, the civil engineer believed that soil as "the loose unconsolidated inorganic material on the earth's surface produced by the disintegration of rocks, overlying hard rock with or without organic matter".

Coarse soil grains have different shape characteristics and surface roughness with low surface area (Davison, 2000). A coarse textured is one comprised primarily of medium to coarse size and particles. Research show that more than 65% of coarse soil consists of sand and gravel sizes. In case of coarse grained soil, the individual grains can be noticeable by the naked eye. Coarse soils can be classified to two types which are gravel and sand. Gravel particles are usually rock fragments such as sandstone or schist which have been formed by weathering and chemical process. Gravel is mainly angular, sub-angular, sub-rounded, rounded, flat or elongated in shape and have a texture of rough, smooth or polished (Knappett & Craig, 2012). According to Das (2011), the size limits recommended by the American Association of State Highway and Transportation Officials (AASHTO) and the Unified Soil Classification system is 75 mm to 4.75 mm and 75 mm to 2 mm. In engineering purposed, gravel is widely used in many roadways where the road surface is made up from gravel especially in rural areas with little traffic flow. In fact, small gravels are also important for the manufacture of

Clay is known for an amount of fine-grained and poor materials that become plastic when wet. In chemical view clays are hydrous aluminum silicates, that the contents are impurities such as potassium, sodium, calcium and etc. The properties of the clay are plasticity, shrinkage value, fine quality of grain, color after firing, hardness, and cohesion. For single particle it is smaller than 0.004 mm(Lagassé, 2012). Over the centuries clays is widely use in the society or civilization. In ancient time clays is use for making cooking pot, bricks, vase and etc. Heat resistant properties and easily moulded which make clays often use. Until now, the clay becomes an important role in the manufacture industries. For example in construction industry which the clay is believe to be the best material because it is sustainable and lost lasting. The clay does not require many processes to be brought to the construction site and environmental friendly. To fulfill the demand of developing green building, by using clay for the rooftop or in construction of mansion, there will be no pollution occurs because of the natural behavior of the element. One of the clays examples that widely used is stoneware. It is grey-ish in colour, heavier and more opaque than porcelain. It is made from siliceous paste and can be burn at high temperature. This type of clay has been produced in China a long time ago. This stoneware clay can be found in near east China. Earthenware