Comparative Evaluation of California Bearing Ratio (CBR) of Natural Offshore Sand and Cement Stabilized Offshore Sand as Road Subbase Material in Swampy Region

Abstract

This investigation focused on the comparative evaluation of California Bearing Ratio values of natural offshore sand and cement stabilized offshore sand as subbase materials for road construction in swampy regions. CBR tests were carried out on the offshore sand sample to ascertain its suitability for road subbase filling. Based on the test results, the CBR of the natural offshore sand was found to be 4.05 percent. After 4% Cement stabilization, the value increased to 12 percent. At 6% cement stabilization, the CBR increased to 26 percent. At 8% cement content, the value obtained was 27 percent. At 10% cement content, the CBR results increased to 31.7 percent. After 12% cement content, the CBR values obtained became 61.4 percent. For sand to be used as subbase material, the Federal Ministry of Works and Housing, Abuja (1997) recommends that the Minimum CBR for subbase should be 30 percent. It is seen that CBR values of natural offshore sand, and at 4% - 8% cement contents did not satisfy requirement for use as subbase material. However, at 10% and 12% cement contents, CBR values of 37.9 percent and 61.4 percent obtained respectively met CBR requirement for subbase. This investigation concludes that cement can be used to stabilize offshore sand to improve the performance of its engineering properties for use as subbase material for construction of road in swampy regions.