Literature Review On Natural Soil

LITERATURE REVIEW

2.1 General

The natural soil behaves like an Expansive soil or cracking soil because these have tendency of shrinking and cracking when moisture content decreases and also have tendency of swelling when moisture content increases. The moisture may come from water leakage or sewer lines, rain, flooding. Soil generally exhibits these properties, when it contains montmorillonite clay minerals.

The engineering properties of Natural soil includes plasticity characteristics, compaction properties, volume stability its strength may be enhanced by adding materials such as Rice husk ash, Sugarcane bagasse ash, cement, sodium chloride etc. The changes in properties of these soils primarily depend upon the type and amount of binder,

This chapter includes a literature review of the structure of soils and their minerals, especially montmorillonite and kaolinite, they are the predominant clay minerals found in natural soil. In general the problems of expansive clay are also discussed together with natural soil stabilization. Special consideration is given to Sugarcane bagasse ash stabilization, including the general soil-Sugarcane bagasse ash reactions, effect of Sugarcane bagasse ash on compaction characteristics, plasticity, volume stability and strength. The changes which occur in clay soil when Sugarcane bagasse ash is added can be divided into two categories, modification and stabilization. During modification calcium ions are absorbed by clay particles in cation exchange reactions. This process starts immediately and

A typical rigid pavement consists of three components: -

(1) Soil sub grade (ii) Base course (iii) Surface course

(i) Soil sub-grade:- The Sub-grade is the foundation layer, the structure which must eventually support all the loads which come on to the pavement. The performance of the pavement is affected by the characteristics of the sub-grade. Desirable properties which the sub-grade possesses are: strength, drainage, ease of compaction permanency of strength. The strength of the sub grade is increased by compaction or in some cases by stabilization.

(ii) Sub-base course:-A sub base is a layer of material between the base and sub-grade. However, a sub-base can be of a lower quality. Sub–base purposes same as base course but little.

(iii) Base Course:-A base course is a layer of granular material which lies immediately below the Wearing surface of the flexible pavement. The base course lies close to the surface course and hence it must possess high resistance to deformation in order to withstand the high pressure imposed upon