The word "soil" comes from the Latin word "Solum" which means earthy material necessary for plant growth. Soil can be defined as a combination of organic ingredients and weathered rocks present in the most superficial part of the earth's crust. Soil Science or Penology (pedos means earth) is the branch of science that deals with the study and classification of soils. Say no to plagiarism. Get a tailor-made essay on "Why Violent Video Games Shouldn't Be Banned"? Get Original Essay To decide the different physical and composite attributes of soil and their separate representation, some classification frameworks are used. Soils are harvested according to their requirement to perform in a certain arrangement of physical conditions. Numerical grouping frameworks were produced depending on the pattern planned for the structure. Soil characterization has proven to be an extremely useful tool for soil engineers. It provides general rules in an experimental way to leverage the field experience of others. Soil can be comprehensively classified as described below: Please note: This is just an example. Get a custom paper from our expert writers now. Get a Custom Essay Classification in Grain Size Evaluation. Grain size structures depended on the measurement of soil grains. In this context the terms clay, fissure, sand and gravel are used to demonstrate only the particle size and the nature of the soil type is not respected. Structural classification. The arrangement of soil solely in consideration of particle size and dispersion rate is known as structural classification framework. This framework specifically names the soil considering the percentage of sand, fissure and clay. Triangular cards are used to organize the soil according to this framework. AASHTO classification framework. AASHTO classification system, also called PRA classification system. It was initially created in 1920 by the U.S. Highway Agency to pool land for freeway subsurface use. This picture is created in light of the size of the molecules and the plasticity attributes of the soil mass. After some updates, this framework was received from AASHTO in 1945. In this framework, soils are separated into seven noteworthy groups. Few of the significant groups are also separated into subgroups. Unified soil classification system. The unified soil classification system was initially created by Casagrande (1948) and was known as the airfield classification system. It was accepted with some modifications by the U.S. Land Reclamation Authority and the U.S. Corps of Engineers. This picture depends both on the size of the grains and on the versatility qualities of the soil. A similar framework with slight modifications was adopted by the ISI for the general design of buildings (IS 1498 – 1970). The IS framework separates soil into three noteworthy groups, coarse-grained, fine-grained, and organic soils and different soil materials. Coarse-grained soils are those with more than half of the material larger than 0.075 mm. Coarse-grained soils are also characterized as rock (G) and sand (S). Rock and sand are also divided into four classifications based on grade, sediment, or soil substance. Fine-grained soils are those for which more than half of the soil is better than sieve estimates by 0.075 mm. They are separated into three subdivisions such as silt or residue (M), clay (c).