Comparative Analysis of Performance and Cost of Chemical Stabilizers for Iowa Granular Roads: Field and Laboratory Evaluation

This paper investigates the role of surface-layer gradation and evaluates the effectiveness of ionic, enzymatic, and water-absorbent solutions as chemical stabilizers through laboratory measurements and field tests on gravel road test sections in Washington County, Iowa. Materials, including soil samples and surface aggregates, were collected from representative sources commonly used in county road construction. The study monitored six test sections over a 1-year period post-construction, documenting distresses and conducting cost and performance comparisons, revealing that the performance of gradation-controlled sections incorporating balanced mixes of gravel, sand, and fines surpassed that of control sections, showing significant enhancements resulting from chemical treatments in overall performance, dust-emission reduction, and structural strength. Water-absorbent solutions proved the most highly effective in moisture retention, enhancing durability, and suppressing dust, leading to a notable 19.1% reduction in overall construction and maintenance costs compared with conventional untreated sections. Enzymatic stabilizers reduced costs by 14.2% and the volume of ionic stabilizers by 11.0%. The study emphasizes the critical role of optimal blend design and chemical treatment in road stabilization projects, and advocates prolonged assessment and strategic stabilizer application to optimize performance under varying environmental and traffic conditions. Ongoing field-data collection aims to further validate these findings and refine gravel road stabilization methods for enhanced cost-effectiveness and durability.