Influence of Fly Ash Properties on Characteristics of Manufactured Angular Fly Ash Aggregates

Abstract

This paper presents the influence of fly ash properties on angular fly ash aggregate (AFAA) and its manufacturing process to be used as a replacement of natural aggregate in concrete. Characteristics of fly ash play an important role in quality of AFAA as fly ash is the major constituent of the raw materials that are used in manufacturing of AFAA. Ample of studies have already been done on production and utilization of round fly ash aggregate (FAA) by pelletization process, but this study deals with innovative work of manufacturing of AFAA by crushing sintered briquettes into required sizes. Unlike round fly ash aggregate, AFAA possesses rough surface that enhance interlocking of these aggregate with paste in concrete. Four different types of AFAA were manufactured in laboratory by using two different samples of fly ash and two different binders. Performance of AFAA showed that specific surface area and chemical composition of fly ash affects sintering behavior of ash and as a result internal microstructure of aggregate also gets affected. Later, eight types of concrete were produced using four types of manufactured FAA at two different water cement ratio 0.45 and 0.50. It was concluded that strength of concrete depends on properties of manufactured AFAA and nature of bond between cement and aggregate at Interfacial transition zone. AFAA used concrete is found to be lighter in weight compared to the concrete of natural aggregate and is economical for use in construction purposes which in turn can save our depleting natural resources and environmental pollution.