IMPROVEMENT OF GEOTECHNICAL PROPERTIES OF CLAY SOIL USING METAKAOLINE

Problematic soils pose a serious challenge to geotechnical engineers when construction activities are to be carried out in/on them. Therefore this paper aims at studying the improvement of the geotechnical
properties of this type of soil using Metakaolin through laboratory studies. The soil samples used were mixed with 0% to 20% Metakaolin at an interval of 5%. The prepared samples were subjected to Atterbarg limits, Compaction, California Bearing Ratio (CBR) and Unconfined Compressive Strength (UCS) tests. The results obtained have shown that the maximum addition of the Metakaolin upon which a maximum stabilization was observed was 5% and above which there was no significant changes in the
soil properties. A decrease in the liquid limit and plastic limit of the soil from 26.8% and 21% for the
control to 25.7% and 20.8% were respectively observed at 5% Metakaolin. The Optimum Moisture
Content (OMC) and Maximum Dry Density (MDD) of the clay soil also changed from 13% and 1.84
Mg/m3 at 0% Metakaolin to 8.2% and 2.18 Mg/m3 at 5% Metakaolin. The soaked CBR value increased
from 12.73% to 15.33% and the un-soaked CBR value also increased from 16.56% to 17.77%. The UCS of the soil increased with an increase in curing period up to 28 days, with a maximum value of 624 kN/m2
which was obtained at 5% Metakaolin. This has therefore shown that the improved soil could be used in the preparations of soil sub-grade and sub-base road constructions, especially in low traffic roads as the
results obtained have met the specifications of such roads in Nigeria.