Determination of the california bearing ratio c.b.r pdf

Public Works Engineering Dept. Faculty of Engineering Civil Engineering Dept. These relationships are as follows: materials and subgrade soils for pavement structural design. Despite its simplicity, the CBR test is tedious and laborious.

The database contained granular as percent passing No. Analysis of the data showed that the CBR values It should be noted that, these relationships are questionable are greatly influenced by percent passing No.

Only seven and MDD. A simple model predicting the CBR as a function of these eleven data points were used to establish Eqs 1 and 2 , parameters was developed using optimization techniques. The respectively. Moreover, the data points used for the goodness of fit statistics of the measured and predicted CBR values using the proposed model indicates a good prediction development of these relationships were typical ranges and accuracy and minimal bias.

Proctor; soaked Many other correlations between CBR and index soil properties were found in the literature. Some of these I. Few models are for coarse materials. In subgrade soils to uniaxial penetration. In Essence, it is a addition, some of the cited models are based on very limited relative measure of the strength stiffness of the unbound materials while others are based on a good number of materials.

The CBR can be measured either in the laboratory or materials. This test was developed by the California Division The correlations found in the literature are based on simple of Highways around s and was subsequently adopted by regression analysis between the CBR either soaked or many countries around the world. In Egypt, CBR is the major unsoaked and the index soil characteristics and compaction input parameter used to characterize the strength of the properties such as liquid limit LL , plastic limit PL , unbound materials and subgrade soils for pavement structural maximum dry density MDD , optimum moisture content design.

Some recent correlations were based on the use of laborious. Thus, many studies have been conducted to estimate Artificial Neural Networks ANNs such as the ones given the CBR from the physical and compaction properties of the in [12], [13] and [14].

The results obtained by these tests are used with the empirical curves to determine the thickness of pavement and its component layers. This is the most widely used method for the design of flexible pavement. Subscribe to our Newsletter. Stay informed - subscribe to our newsletter.

Email The subscriber's email address. Search AboutCivil. Thus, the total thickness of the flexible pavement needed to cover the subgrade of the known CBR value is obtained. The thickness of construction over subgrade could be obtained from the design chart knowing the CBR value of the sub-base. Similarly, find the thickness of the base course and wearing course with the help of corresponding CBR value.

Types of slope failure — Causes and Improvement of slope failure in Soil. Black cotton soil — Properties, Chemical composition, and Stabilization. Apply the loads to the penetration piston at the rate of 1. In some cases the initial penetration takes place without a proportional increase in the resistance to penetration and the curve may be concave upward.

To obtain the true stress-strain relationships, correct the curve having concave upward shape near the origin by adjusting the location of the origin by extending the straight the portion of the stress strain curve down ward until it intersects with x-axis.

Determine the corrected load values at 2. Date :………………………….. ASTM D 3. The Asphalt Institute. The Asphalt Handbook 4.