Laboratory Investigation of Desert Road Subgrade Stabilization Using Lime, Cement, RRP, and Polyvinyl Acetate Polymer: A Case Study of the Shadad-Nehbandan Road, Iran

More than two-thirds of Iran's land area is covered by desert regions, where weak, saline, and collapsible soils pose significant challenges to road construction. This study presents a comprehensive laboratory investigation into the stabilization of desert road subgrade soil from the Shadad-Nehbandan road (Iran) using five stabilizers: lime (۲-۱۰%), cement (۴-۱۰%), RRP (۰.۰۱-۰.۰۳%-a liquid ionic stabilizer), polyvinyl acetate (PVA) polymer (۱-۷%), and a control. Standard Proctor compaction, unconfined compressive strength (UCS), California Bearing Ratio (CBR), Atterberg limits, swelling, pH, and scanning electron microscopy (SEM) tests were conducted under various curing and soaking conditions. Results show that cement significantly improves UCS (۲۴ times control after ۲۸ days) and CBR (up to ۵۰ times) with minimal strength loss (۲۰%) after ۷ days of soaking. Lime exhibits long-term strength gain (up to ۴ times after ۹۰ days) but poor short-term performance. RRP and PVA show negligible or unacceptable strength under wet or soaked conditions, with PVA losing up to ۹۸% strength after soaking. Economic analysis confirms cement as the most cost-effective stabilizer. This research emphasizes that non-traditional stabilizers must be rigorously tested before field application.

کلیدواژه ها:

Desert soil stabilization ، lime ، cement ، RRP ، polyvinyl acetate ، unconfined compressive strength ، CBR ، SEM ، economic comparison