Fly Ash-Calcium Chloride Stabilization in Road Construction

Abstract

Both fly ash and calcium chloride have been used in a wide variety of roadway construction applications. Engineering applications of both Class C and Class F fly ashes include portland cement concrete, soil and road base stabilization, flowable fills, grouts, structural fills, and asphalt filler. Until recently, the primary roadway application for calcium chloride has been as a dust-controlling agent on unsurfaced roads. Ongoing research at Texas A&M and Texas Transportation Institute has concluded that when the two are strategically combined within a roadway mix design, their individual mineralogical and physicochemical characteristics interact to further enhance the service performance of the roadway. Although the fines content in the roadbed composition is critical, there is a synergistic effect on the strength generated when calcium chloride is added along with fly ash. This synergistic blending of fly ash and calcium chloride is referred to as “surface-activated stabilization.’'