Effect of Moisture Variation on the Strength Characteristics of Laterite: A Case Study of Abeokuta, Ogun State, Nigeria
Abstract
Nigeria, a country in the tropical region is characterized with heavy rainfall and high temperature. It is therefore appropriate to say that climatic factors affect its roads. Many of the roads are flooded with water after heavy rains due to inadequate drainage system. The roads in Ogun State are plagued with various distresses and failures. This study examined the effect of moisture variation on the strength characteristics of laterite in Abeokuta, Ogun State, Nigeria. Samples of laterite soils were obtained from Oke-Mosan burrow-pit, Abeokuta and engineering properties such as the natural moisture, sieve analysis, Atterberg limits, compaction and the strength characteristics were evaluated. The un-soaked California Bearing Ratio (CBR) value of the soil compacted at optimum moisture content was 32%. The effect of moisture variation on the strength of laterite was determined from results of CBR of the compacted laterite soils soaked in water for 5 days to simulate the worst moisture condition in the field for the laterite. The result showed that an increase in the soaking period of the compacted soil sample from 1 to 5 days result in decrease in the CBR of the soil from 6.57% to 6.16% also, there was also increase in the bulk density from 2060.74 kg/m3 to 2169.20 kg/m3. The study revealed that affinity for water and the corresponding low shear strength of the laterite soils are responsible for the failure of roads in Abeokuta metropolis.
