Effect of Soaking on the CBR-Value of Subbase Soil


The effect of soaking on the top and bottom CBR value of a sub-base is studiedin this paper.Fourteen CBR samples were prepared at 95% relative modified AASHTOcompaction .Two CBR samples were prepared for each soaking period of0,4,7,14,30 and 60 days. These samples were prepared and compactedmechanically in the laboratory. The first group was tested in case of unsoakedwhile the second group was tested in case of soaking.The results showed that, a significant drop in the CBR for top and bottom due tothe soaking was observed compared with natural case due to softening of soilparticles Which means that the bearing capacity of subbase soil decrease withincrease of soaking time. Most of decrease in soaked CBR value is pronouncedinthe first days for top and bottom CBR, respectively. And it dropped to 20%and23%value for top and bottom after 60 days soaking period and this drop is infull of weakness of soil with soaking.