Effect of fly ash on the service life, carbon footprint and embodied energy of high strength concrete in the marine environment

Abstract

Durability is one of the primary considerations in designing concrete structures in aggressive environments. This paper presents a study of concretes containing fly ash as 30% and 40% of the total binder in regards to service life, carbon footprint and embodied energy. A simple deterministic service life estimation technique using the well-known Fick’s law was applied to assess the service life of similar grade concrete mixes against the corrosion due to chloride diffusion. The parameters needed to predict the service life of concrete were determined from laboratory experiments. Compared to control concrete, fly ash concretes showed less chloride diffusion which is considered as the dominant form of attack in reinforced concrete structures in the marine environment and thus the latter is more durable or has a longer service life than the former. Finally, this paper presents the application of life cycle assessment to measure carbon footprint and embodied energy consumption saving benefits of the use of more durable fly ash concretes in the aggressive marine environment. About 36%–43% of carbon footprint and 36%–38% of embodied energy consumption can be avoided for different concrete covers due to replacement of 40% cement with fly ash.