Prediction of California Bearing Ratio (CBR) using Dynamic Cone Penetrometer (DCP) for Soils from Second District in the Province of Sorsogon

California Bearing Ratio (CBR) is one important parameters considered in design and construction of pavement. However, since CBR cannot be easily determined in the field or in laboratory, CBR can be related to other in situ test such as Dynamic Cone Penetrometer (DCP). In this study, laboratory soaked CBR value and field DCP test were correlated for soils from second District in the Province of Sorsogon allowing to expediently determine the subgrade strength for pavement design. Fifteen soil samples from proposed road construction in the Sorsogon second district were taken for laboratory soaked CBR test.  DCP test have been performed in the field on different pits 0.5 m depth from Natural Ground Line to record the penetration value. On the same pits, soil samples is extracted directly where the DCP test performed and bring to laboratory for CBR test and some soil index properties determination. To analyze if a relationship exists between CBR and DCP, Pearson Product Moment Coefficient are utilized setting CBR as independent variables. Then, simple regression analysis has been performed to determine relationship of CBR value with DCP penetration. Regression analysis results showed that soaked CBR value have strong relation with DCP index having coefficient of determination (R²) of 0.76. Comparison between the developed equation and previous study shows conservatively similar regression curve and result suggesting validity of the developed equation.