Abstract:
The present study investigated the utilization of plastic wastes as reinforcement to improve the strength and
swelling behavior of weak subgrade expansive soils and reduce plastic pollution. Expansive soils are known for
their volume change during different seasons, while plastic waste is the most hazardous waste pollutant material
that causes damage to the environment and organisms. Utilizing plastic wastes in subgrade construction reduces
the quantity of waste and improves the problematic behavior of expansive soils.
The studied soil is categorized as expansive clay soil according to the AASHTO soil classification system.
Various geotechnical laboratory tests were conducted by varying the plastic strip sizes with treatment per centages of 0%, 0.25%, 0.5%, 1%, 1.5% and 2%. The study found that swelling percentages and compaction
parameters were decreased with an increase in plastic waste strips. As percentages of plastic strips increase, CBR
values increase while unconfined compressive strength increases up to 0.5% addition of plastic strips and then
slightly decreasing. The cohesion of the soil increases up to 1.5% of plastic strips addition. The study recom mends that the utilization of plastic waste in subgrade road construction is the best alternative to improve the
strength of expansive soils and reduce environmental pollution.
