Abstract:
An experimental program was conducted to explore the impact of microsilica and cement stabilizers
on the geotechnical characteristics of lateritic soil. Portland limestone cement was added in varying
proportions of 2%, 4%, 6%, 8% and 10% by weight of dry soil and combined with microsilica which
was added in proportions of 0%, 2%, 4%, 6% and 8% by weight of dry soil. Compaction tests, CBR tests
and UCS tests were carried out on various samples with different combinations of the stabilizers.
Experimental results shows that the addition of cement led to a slight decrease in OMC and an
increase in maximum dry density for all percentages of cement added to the soil. The addition of
microsilica resulted in further increase in OMC and a slight decrease in MDD of the soil-cement mix.
The peak value of maximum dry density for the modified lateritic soil was obtained at 8% cement and
2% microsilica content, which gave 2.10g/cm3
and OMC of 15.49%. CBR (soaked and unsoaked)
values for all percentages of the soil-cement mix increased when microsilica was added up to 4%, and
then decreased between 4% and 6%. The maximum CBR values for both soaked and unsoaked were
obtained at 8% cement and 4% microsilica content, which gave 88% and 52% respectively.
Unconfined compressive strength (UCS) test carried out on a few samples with relatively higher CBR
values, shows that there was an increase in UCS with cement and microsilica content in addition to
curing period. Of all these three factors, addition of microsilica led to the greatest increase in the UCS
of the stabilized soil. Results of some geotechnical properties of the stabilized soil compared with the
Federal Ministry of Works (Nigeria) standards, confirms that the stabilized soil can be used as a sub grade and sub-base for road construction. Multiple regression models were developed to predict
simple relationships between the stabilizer contents and the different geotechnical properties tested.
