Sulfate-Heaving Studies on Chemically Treated Sulfate-Rich Geomaterials

Abstract

Sulfate heaving often occurs when soils rich with sulfates are treated with calcium-based stabilizers such as lime and cement materials. This heaving has inflicted severe distress on several transportation infrastructure types including highways, runways, tunnel liners, dwellings, and other structures. Soil and environmental factors can influence the sulfate-heaving phenomenon in soils. This paper summarizes lessons learned from sulfate-heaving problems documented in the United States. It includes a summary of the various test methods used to quantify sulfate amounts and different treatment methods applied to sulfate soils to mitigate sulfate-induced heaving distress. In an experimental study documented in this paper, percentage changes in sulfates and reactive alumina before and after treating soils with lime and cement additives are analyzed to explain their contributions to ettringite mineral formation and related soil heaving. A method using reactive alumina and soluble sulfate measurements in effective screening of stabilizer treatments for sulfate rich soils is presented. An unmanned aerial inspection was carried out to inspect the heaving distress on a pavement section built over high-sulfate soils in Texas. This study showed an effective combined lime and fly ash treatment of high-sulfate soils with an extended mellowing period. Updates from ongoing and recently completed investigations of sulfate-heaving mitigation and their salient findings are discussed and presented.