EFFECT OF DUST RATIO ON THE CONSOLIDATION BEHAVIOUR OF COMPACTED LATERITIC SOILS

Abstract

The study was undertaken to evaluate the effect of dust ratio on consolidation properties ofcompacted lateritic soils. Three laterite samples designated as A, B and C with dust ratiosranging between 0.2-0.4, 0.4-0.6 and 0.6-0.8 were used for the study. The laterite samples weresubjected to various testing which include: sieve analysis test, specific gravity test, compactiontest, atterberg limit test and consolidation test. Results obtained from sieve analysis test revealedthat the samples were classified as A-2-6, A-7-5 and A-7-6 according to AASHTO SoilClassification System, SC (sand mixed with clay) and CH according to Unified SoilClassification System, the specific gravity of the samples were 2.66, 2.62 and 2.55, the liquidlimit, plastic limit and plasticity index of the samples were 26.8%, 32.6%, 33.9% while theplastic limit was 15.83%, 17.57%, 20.14%, the plasticity index of the samples were 10.97%,15.03% and 13.44%, the maximum dry unit weight of the samples were 19.55kN/m3 ,17.18kN/m3 and 16.69kN/m3 , the optimum moisture content were 7.86%, 14.21% and 14.88%,the coefficient of consolidation of the samples were 0.079mm2 /min, 0.081mm2 /min and0.083mm2 /min, the coefficient of volume compressibility of the samples was 0.0018mm2 /kpa,0.0021mm2 /kpa and 0.0021mm2 /kpa while the compression index of the samples was0.0022mm2 /kpa, 0.003mm2 /kpa and 0.001mm2 /kpa. The study therefore concluded that dust ratiohas significant impact on consolidation properties of compacted lateritic soils as lateritic soilswith high amount of dust ratio has high coefficient of consolidation and coefficient of volumecompressibility.