Title: Use of Biomass and Co-Fired Fly Ash in Concrete

Author(s): Christopher R. Shearer and Kimberly E. Kurtis

Publication: Materials Journal

Volume: 112

Issue: 2

Appears on pages(s): 209-218

Keywords: biomass; durability; fly ash; pozzolan; strength; supplementary cementitious material; sustainability; workability

DOI: 10.14359/51686827

Date: 3/1/2015

Abstract:
In this study, biomass and co-fired fly ashes are examined for use as supplementary cementitious materials. These ash sources are not addressed in the current American standard for fly ash and natural pozzolan use in concrete (ASTM C618-12a). The influence of these ashes on early-age hydration kinetics, workability, setting time, strength, permeability, and sulfate resistance is investigated. The findings demonstrate that co-fired fly ash, when conforming to current ASTM C618 specifications, can impart similar properties to concrete as coal fly ash. Thus, the potential of an ash to be used as a supplementary cementitious material is related to the chemical and physical properties of the ash, and not necessarily to its source (that is, coal or co-firing). Current standards should consider permitting co-fired fly ash sources that meet existing ASTM C618 requirements and any additional requirements deemed necessary to ensure their satisfactory performance when used in concrete.