DBR LAB Report Example | Topics and Well Written Essays - 2000 words

DBR - Lab Report Example e such that sections of the pavement are not subjected to excessive deformation that would otherwise result in settlement of the section or localized deformation. One of the empirical methods used in the design of pavements is the California bearing ratio test abbreviated as CBR test. CBR value is determined by carrying out a CBR test on the subgrade soil. The CBR value depicts an index that shows the soil bearing capacity and the soil strength. Using the CBR value, sub – base and base material of a pavement to be constructed can be easily designed (Knapton). Using the CBR value, evaluations of the strengths of the soils can be established by using CBR value as an indicator. The CBR value typically represents a percentage of the soil with a standard crushed soil from California. Ultimately, the CBR value is mainly used in the quantification of the response of the subgrade and pavement to loading (Indian Institute of Technology Kanpur). There are various factors that affect the CBR test. These include the soil density, the soil texture and the soil moisture. Thus, the testing procedure to be used for a specific CBR test is completely dependent on the material type being tested. A drawback to the CBR test is that it gives the total thickness of material to be applied above the subgrade. The thickness is constant for a particular pavement irrespective of the materials that are used in the construction of the layers (Yoder and Witczak). In the California bearing Ration test, the objectives are the determination of the CBR value of the soil that is being considered to be used as a foundation of a pavements. This is mainly done to facilitate the evaluation of the subgrade soil strength (Purushothama). It should be noted that CBR does not provide information about the soil properties such as cohesion shearing resistance etc. 4.5 Kg of the sample to be tested was collected from the field. A soil sample was then taken from this sample a compacted in a CBR mould in 3