Interaction of Coal Fly Ash with Concrete Surfactants: Diffusional Transport and Adsorption

摘要

The most important commercial outlet for coal ash is in the concrete industry as a partial replacement for Portland cement. In many concrete mixtures specialty surfactants are added to enhance the entrainmcnt and retention of air during mechanical agitation. Porous carbon particles, if present in fly ash, can adsorb these surfactants and disrupt the air entrainment process. Previous work has shown that the degree of ash / surfactant interaction cannot be accurately correlated to carbon content alone, but depends on the nature and properties of the carbon present. This paper further examines the fundamentals of the adsorption process, with an emphasis on time-dependent effects and the relationship between sorptive activity and carbon surface chemistry.