Cement Stabilization Characteristics of Shale Subgrade of parts of the Lower Benue Trough, Southeastern Nigeria

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Author(s) Nnamdi E. Ekeocha | Enuvie G. Akpokodje
Pages 78-84
Volume 3
Issue 1
Date January, 2014
Keywords Pavement, failure, stabilization, cement, unconfined compressive strength, California Bearing Ratio, plasticity
Abstract

The effects of weathered shale subgrade and cement stabilization on road pavement durability [incessant failure] within the Lower Benue Trough were investigated. The soils classified as A-2-4, A-2-6, A-2-7, A-4 and A-7-6 on the AASHTO classification scheme with maximum dry density (MDD) and optimum moisture content (OMC) values of 1.76 - 2.03 gcm-3 and 12 - 19% respectively. The plasticity recorded values between 20 and 66% for the liquid limits, 6.7 – 24% for the plastic limits and between 7.6 and 43% for the plasticity index. The soaked CBR ranged between 3.5% - 38.0% which classifies the samples as non-weak soils. Although the results of the CBR may suggest that the materials meet the Nigerian national standard pavement design specification, the liquid limit and plasticity index values exceed recommended values, which most probably explain the widespread pavement failures observed within the area. The range of the soaked unconfined compressive strength (UCS) is 0.01 - 0.14Nmm-2 for various percentages of cement (3 – 12%). The soils showed some level of improvement when treated with 10 - 12% cement.

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