Title: Effect of Fly Ash on Physical Properties of Concrete

Author(s): Steven H. Gebler and Paul Klieger

Publication: Symposium Paper

Volume: 91

Issue:

Appears on pages(s): 1-50

Keywords: abrasion resistance; absorption; admixtures; bleeding (concrete); cold weather construction; compressive strength; concretes; curing; drying shrinkage; fly ash; hardened concretes; mineral admixtures; pozzolans; setting (hardening); water content.

DOI: 10.14359/10063

Date: 2/1/1986

Abstract:
Tests of portland cement concretes contain-ing Class F and Class C fly ashes from ten different sources were conducted to evaluate mixing water requirement, time of setting, bleeding, compressive strength, drying shrinkage, abrasion resistance, and absorption. The effects of moisture availability and temperature during curing were also examined. Mixing water requirement was reduced for concretes with Class C fly ash. There was no consistent water reduction when Class F fly ashes were used. Slight to signifi-cant retardation of setting time was noted for concretes with fly ash. Setting time generally increased as concrete mixing water requirement increased. Concretes with fly ash showed less bleeding than control concretes. Concretes with Class C fly ash showed less bleeding than concretes with Class F fly ash. Concretes containing Class C fly ash developed higher early age compressive strength than concretes with Class F fly ash. Compressive strengths of concretes with Class F fly ash were more susceptible to low curing temperatures than those for concretes with Class C fly ash. At early ages, compressive strength of concretes with fly ash, regardless of class, was essentially unaffected by moisture availability. Abrasion resistance of control concretes and concretes containing fly ash was dependent on compressive strength. Drying shrinkage and absorption of the concretes were generally unaffected by the use o f f l y ash.