CORROSION RESISTANCE ASSESSMENT OF STEEL BARS EMBEDDED IN THE CIRCULATING FLUIDIZED BED OF FLY ASH AND BOTTOM ASH CONCRETE

Abstract

This study investigates the integration of industrial waste, specifically fly ash (FA) and bottom ash (BA), as sustainable substitutes for cement and sand in concrete production. The utilization of these materials addresses environmental concerns related to natural resource depletion and waste accumulation from coal-fired power plants. FA and BA were used at varying proportions (15% FA:50% BA and 30% FA:50% BA) in concrete mixtures. The mechanical properties, including compressive and flexural strengths, were evaluated at 7, 28, and 90 days, alongside an accelerated corrosion test to assess chloride-induced corrosion resistance. Microstructural analysis using Scanning Electron Microscopy (SEM) further complemented the study. The results revealed that the 15% FA:50% BA mixture achieved the highest compressive strength and demonstrated superior resistance to chloride-induced corrosion, attributed to enhanced microstructure densification through pozzolanic reactions. However, both FA-BA mixtures exhibited lower flexural strength compared to control concrete, highlighting the brittleness introduced by the substitutions. SEM analysis confirmed reduced porosity and improved particle bonding in the modified mixtures. These findings suggest that a mix of 15% FA and 50% BA provides an eco-friendly and durable alternative for concrete applications in chloride-exposed environments, with future potential for optimizing flexural properties through fiber reinforcement.