Report on High-Volume Fly Ash Concrete for Structural Applications

Description

High-volume fly ash (HVFA) concrete is a sustainable construction material when proportioned properly and used in appropriate construction applications. This report summa-rizes published data on the composition and properties of the material, such as workability, strength, and durability. The report affirms the viability of HVFA concrete for structural applications and discusses construction issues. HVFA concrete is defined as having a large replacement by mass of portland cement with fly ash.

Malhotra (1986) defined HVFA concrete as concrete containing 50 percent or more fly ash by mass of total cementitious materials, and Ram me and Tharaniyil (2000) defined it as concrete with 37 percent or more fly ash by mass as total cementitious materials. Naik and Ram me (1985) tested HVFA concrete using ASTM C618 Class C fly ash mixtures and having water-cementitious material ratios (w/cm) ranging from 0.42 to 0.57, without the use of high-range water-reducing admix-tures. In 1986, however, a significant research program was initiated to explore the possibility of HVFA concrete attaining compressive strengths of 7250 psi (50 MPa) or higher for structural applications (Malhotra 1986).

This research used concrete mixtures containing ASTM C618 Class F fly ash, 0.30 w/cm, and high-range water-reducing admixtures. The results of this work showed the potential of HVFA concrete as a sustainable material with workability, strength, and durability exceeding that of conventional port-land-cement concrete having similar cementitious content. Summaries of the results on HVFA concrete using Class F fly ash are given by Malhotra (1992, 2002), Bilodeau and Malhotra (2000), and Malhotra and Mehta (2012).Low-strength HVFA concrete mixtures are not covered herein. In this document, HVFA concretes that have minimum specified compressive strengths of 2500 psi (17 MPa) are discussed.