Abstract:
This study presents an evaluation of use of the cement waste as chemical
stabilizers and recycling fiber glass wastes and plastic waste (PET Bottles)
as soil reinforcement, for improving the strength and stability of soils.
An experimental program was conducted to investigate the effect of
materials waste and evaluate the efficiency of their use on clay soil as
stabilizers, this was achieved based on a study of the effect of materials
waste on the properties of clay soil such as optimum moisture content
(OMC), maximum dry density and shear strength parameters (cohesion(c)
and angle of friction (ɸ)). The aim was to determine the optimum content of
each of these materials waste and consequently, to reduce the pollution
which results from accumulation of (plastics waste (PET: Polyethylene
Teraphathalate), fiber glass and cement waste). A series of laboratory
compaction, triaxial and California Bearing Capacity (CBR) tests were
carried out.
Various percentages of cement waste (3, 6, 9, 12 and 15%) of dry weight of
soil was added to clay soil and tested. Also soil was reinforced randomly by
different percentage (0.5, 1.5, 3, 6, 9 and 12 %) of dry weight of soil by
fiber glass (length 10-30mm) and Plastic (PET) bottles strips waste (length
and width (5-10mm)). Soil specimens were compacted at maximum dry
density.
Results of soil treated by cement waste indicate that addition of cement
waste increased the shear strength (385.38 mPa at age 2hours) and CBR
()to a maximum value for up to 9% addition, when the percentage of
addition of cement waste was equal to or greater than 9% soil became non
plastic. The OMC decreased with an increase of more than 12% of cement
~ V ~
waste content. The dry density of the soil decreased from 1.56 to 1.48 g/cm3
with an increasing of cement waste content. `
Results of soil reinforced by fiber glass and PET bottle indicate that an
increasing of fiber glass and plastic bottle content decreased the maximum
dry density and increased the OMC. The highest increase in strength value
(386.82 mPa) was achieved when the soil was reinforced by 3.0 % of fiber
glass content and (386 mPa) when the soil was reinforced by 1.5% of
plastic bottle content and the highest CBR value was achieved at 3.0% of
fiber glass and PET bottle content respectively.
The highest CBR value was 8.3 times the CBR of natural clay soil for soil
treated by cement waste, 3.6 times the CBR of natural clay soil for soil
reinforced by fiber glass and 2.1 times the CBR of natural clay soil for
reinforced by PET bottle waste.
As a result of this study it is recommended to use not more than 9% of
cement waste, 3% fiber glass waste and (1.5% to 3%) PET bottle waste as
stabilizers to improve the shear strength and CBR of clayey soil.
