Fly ash-based Reactive Powder Concrete with coarse aggregate and GGBFS: Mechanical properties and sustainability

¹ Structural Engineering Research Unit, Faculty of Engineering, Mahasarakham University, Maha Sarakham, 44150, Thailand
² Water Distribution System Design Department, Metropolitan Waterworks Authority, Bangkok, 10210, Thailand
³ Water Treatment, Transmission System and Civil Work Design Department, Metropolitan Waterworks Authority, Bangkok, 10210, Thailand
⁴ Department of Civil Engineering, Faculty of Engineering, Kasetsart University Kamphaeng Saen Campus, Nakhon Pathom, 73140, Thailand

^* Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.

Abstract

This study examines the incorporation of ground granulated blast-furnace slag (GGBFS) into fly ash-based Reactive Powder Concrete (RPC) with coarse aggregate, aiming to enhance sustainability while preserving mechanical performance. The work focuses on optimizing flowability, strength, and carbon efficiency under standard curing conditions. The binder system comprised cement (33-55%) and GGBFS (0-22%), together with fixed proportions of fly ash (38%) and silica fume (8%) by weight. Results indicate that moderate GGBFS replacement improved both workability and strength, whereas higher replacement levels markedly reduced the carbon footprint. The RPC mixtures achieved flow values of 203-225 mm, 28-day compressive strengths ranging from 123.9 to 143.5 MPa, and flexural strengths between 20.1 and 24.4 MPa. Overall, the findings show that integrating GGBFS into fly ash-based RPC enables the development of low-carbon, cost-efficient, and high-strength concrete, offering strong potential for sustainable large-scale infrastructure applications.