Correlation of LWD, CBR and Cyclic-Triaxial Tests

The resilient modulus of subgrade is an important factor in pavement design which is determined by cyclic triaxial test on cylindrical samples. Due to test complication and difficulties, other tests could be useful if there is an appropriate correlation between results. Nowadays non-destructive testing of pavement is growing in the world as they are rapid, without destruction and have precision measuring equipment. In recent years the application of LWD has been widely developed. This device evaluates pavement structure of several locations in short time with high accuracy. The main objective of this paper is to evaluate the LWD feasibility in order to estimate subgrade resilient modulus and the quality control of construction. So the in-construction road path have been chosen, then LWD field test, CBR laboratory test and finally cyclic triaxial have been done. Also the compaction percentage of each point determined to compare with LWD results. Comparing modulus obtained from LWD results to other test lead to establish modelsand equation which the best relation between LWD modulus and resilient modulus acquired. Also LWD result scattering is less than CBR. Moreover LWD device has enough efficiency for structural evaluation of unbound material and quality control of pavement sublayers.