Enhancing the CBR Strength and Freeze–Thaw Performance of Silty Subgrade Using Three Reinforcement Categories
Abstract: Silty subgrade soil
cannot satisfy the requirements of highway construction because of its low
strength and durability problems. A wide range of reinforcements have been used
to improve soil performance. Improving the soil properties has caused more
interest in identifying new accessible resources for reinforcement. This paper
investigates the effect of including different reinforcement types on reducing
the rapid accumulation of pavement damage caused by freeze–thaw cycles or low
strength of a silty pavement foundation. The improvement of CBR strength and
freeze-thaw behavior was tested with the inclusion of three reinforcement
categories: i) randomly distributed fibers (natural palm fibers and chemical
polypropylene fibers), ii) chemical additives (lime and cement), and iii) waste
or by-product materials (fly ash and silica fume). To represent unsaturated and
saturated soil conditions for various field applications, both unsubmerged and
submerged samples were investigated. Mass losses were also calculated after
freezing–thawing cycles as criteria for durability behavior. The test results
for the reinforced specimens were compared with unreinforced samples to clarify
the effectiveness of each reinforcement type and content. Unsubmerged samples
especially that reinforced with waste materials provided a significant
improvement in CBR strength. For submerged conditions, the best performance was
observed from the specimens treated with chemical additives. 10% of cement
reinforcement and 20% of waste materials provide the highest resistance against
the freeze–thaw cycles.
Author: Ahmed Ebrahim Abu
El-Maaty
Journal Code: jptsipilgg160016
