Effects of Combined Lime and Fly Ash Stabilization on the Elastic Moduli of Montmorillonitic Soils. Final Report

摘要

The study reports the results of physical, mineralogical, and micromorphological tests on laboratory prepared mixtures of bentonite (75wt%), Class C fly ash (20wt%), and lime (5wt%). Combined results of X-ray powder diffraction, scanning electron microscopy, compressive strength tests, and elastic modulus calculations on the same test specimens after curing for periods of time up to 180 days at 23 C or 50 C provide much insight on the stabilization reaction mechanisms in a montmorillonite-rich material. Ettringite, C-S-H gel, and afwillite create a 3-dimensional network of bound particles that is responsible for increased compressive strengths and elastic moduli 15-17 times greater than the untreated bentonite. Test results produced after one day of curing at 50 C are comparable to those obtained after 28 days of curing at 23 C.