Abstract: A clay soil classified as A-7-6 and CH soil according
to AASHTO and unified soil classification system respectively, was
stabilized using A-3 soil (AASHTO soil classification system). The
clay soil was replaced with 0%, 10%, 20%, to 100% A-3 soil,
compacted at both British Standard Light (BSL) and British Standard
Heavy (BSH) compaction energy levels and using Unconfined
Compressive Strength (UCS) as evaluation criteria. The Maximum
Dry Density (MDD) of the treated soils at both the BSL and BSH
compaction energy levels showed increase from 0% to 40% A-3 soil
replacement after which the values reduced to 100% replacement.
The trend of the Optimum Moisture Content (OMC) with varied A-3
soil replacement was similar to that of MDD but in a reversed order.
The OMC reduced from 0% to 40% A-3 soil replacement after which
the values increased to 100% replacement. This trend was attributed
to the observed reduction in void ratio from 0% to 40% replacement
after which the void ratio increased to 100% replacement. The
maximum UCS for the soil at varied A-3 soil replacement increased
from 272 and 770 kN/m2 for BSL and BSH compaction energy level
at 0% replacement to 295 and 795 kN/m2 for BSL and BSH
compaction energy level respectively at 10% replacement after which
the values reduced to 22 and 60 kN/m2 for BSL and BSH compaction
energy level respectively at 70% replacement. Beyond 70%
replacement, the mixtures could not be moulded for UCS test.
Abstract: The need to save time and cost of soil testing at the
planning stage of road work has necessitated developing predictive
models. This study proposes a model for predicting the dry density of
lateritic soils stabilized with corn cob ash (CCA) and blended cement
- CCA. Lateritic soil was first stabilized with CCA at 1.5, 3.0, 4.5 and
6% of the weight of soil and then stabilized with the same
proportions as replacement for cement. Dry density, specific gravity,
maximum degree of saturation and moisture content were determined
for each stabilized soil specimen, following standard procedure.
Polynomial equations containing alpha and beta parameters for CCA
and blended CCA-cement were developed. Experimental values were
correlated with the values predicted from the Matlab curve fitting
tool, and the Solver function of Microsoft Excel 2010. The correlation
coefficient (R2) of 0.86 was obtained indicating that the model could
be accepted in predicting the maximum dry density of CCA stabilized
soils to facilitate quick decision making in roadworks.