Effect of Remoulded Density on Creep of Black Cotton Soil

Abstract

A black clay soil collected using the method of disturbed sampling, from Bako village, along Gwagwalada road, Abuja, was characterized and tested for mineral composition. The clay was compacted at four different compaction energy levels (Reduced Standard Proctor, Standard Proctor, West African Standard and Reduced Modified Energy Levels). The resultant compaction characteristics were used to remold the clay for 72 hours loading consolidation test which was used to evaluate the consolidation and creep parameters as well as the magnitude of creep. Results showed that the clay classified as Clay of High Plasticity (CH) according to unified Soil Classification System and composed predominantly of secondary minerals including montmorillonite. The recompression index was observed to reduce from 0.0522 at reduced standard proctor energy level through 0.0472 at standard proctor energy level to 0.0243 at West African standard energy level which ended up with 0.0143 at reduced modified energy level. The compression index however, reduced from 0.489 at reduced standard proctor energy level to 0.398 at standard proctor energy level through 0.305 at West African standard energy level after which the value increased to 0.324 at reduced modified energy level. The trend of creep shows increase from 248.6 mm at reduced standard proctor to 350.6 mm at standard proctor compaction energy level after which the value reduced to 226.5 mm at reduced modified compaction energy level.