Effect of Fly Ash on the Durability Properties of High Strength Concrete

Document Type : Primary Research paper

Authors

Assistant Professor Department of Civil Engineering Nehru Institute of Technology

Abstract

Utilization of fly ash as a supplementary cementitious material adds sustainability to
concrete by reducing the CO2 emission of cement production. The positive effects of fly
ash as a partial replacement of cement on the durability of concrete are recognized
through numerous researches; however, the extent of improvement depends on the
properties of fly ash. In this study, durability properties of high strength concrete
utilizing high volume Class F fly ash sourced from Western Australia have been
investigated. Concrete mixtures with fly ash as 30% and 40% of total binder were used
to cast the test specimens. The compressive strength, drying shrinkage, sorptivity and
rapid chloride permeability of the fly ash and control concrete specimens were
determined. The 28-day compressive strength of the concrete mixtures varied from 65 to
85 MPa. The fly ash concrete samples showed less drying shrinkage than the control
concrete samples when designed for the same 28-day compressive strength of the
control concrete. Inclusion of fly ash reduced sorptivity and chloride ion permeation
significantly at 28 days and reduced further at 6 months. In general, incorporation of fly
ash as partial replacement of cement improved the durability properties ofconcrete.

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