Properties of high performance concrete systems incorporating large amounts of high-lime fly ash

Abstract

This research was undertaken to evaluate the engineering properties of high-lime (ASTM Class C) fly ash concretes. An air-entrained reference concrete mixture without fly ash was proportioned to have 28-day compressive strength of 41 MPa. Additionally, concrete mixtures were also proportioned to have cement replacement with Class C fly ash in the range of 0–70% by weight. For each concrete mixture, specimens were made to evaluate compressive strength, tensile strength, flexural strength, modulus of elasticity, shrinkage, abrasion resistance, air permeability, water permeability, chloride ion permeability, air-void parameters, freezing and thawing durability, and salt scaling resistance, of hardened concrete. The results of this study established that high-performance concrete incorporating Class C fly ash at 30% cement replacement can be proportioned for high-strength applications. In general, concrete mixtures up to 50% cement replacement with fly ash showed satisfactory performance with respect to strength and physical durability properties appropriate for structural applications.