Investigation of carbonation behaviour on high volume GGBFS use in rigid road pavement concrete

Investigation of carbonation behaviour on high volume GGBFS use in rigid road pavement concrete

B. Mehdizadeh 1*, K. Vessalas 2, A. Castel 3, M Mortazavi 4

1 PhD candidate, School of Engineering and Information Technology, University of Technology Sydney 2 A/ Professor, Head of Discipline, Structural and Materials Engineering, University of Technology Sydney3 Professor, Technical Editor of Concrete in Australia, University of Technology Sydney,  4Senior lecturer, School of Civil and Environmental Engineering University of Technology Sydney

ABSTRACT

This study investigates the carbonation behaviour of high-volume ground granulated blast furnace slag (GGBFS) in rigid road pavement concrete, focusing on reducing carbon emissions and improving concrete strength and durability. The research examines the effects of GGBFS and fly ash (FA) content on the compressive and flexural strengths of concrete and carbonation behaviour. The study utilises shrinkage-limited cement (SL), FA, GGBFS, and various aggregates as raw materials with a fixed water-to-binder ratio (0.45). This study reveals that compressive strength fluctuates when a significant amount of GGBFS was applied. Among the mixes with fixed 20% FA content, the mix with 40% GGBFS content demonstrates the highest compressive strength, while exceeding 40% GGBFS content leads to a significant decline in strength. The flexural strength also decreases with increasing GGBFS content. In addition, the study shows that increasing GGBFS content generally leads to higher carbonation depths, while the effect of FA content is minimal. The carbonation rates are significantly higher for mixes incorporating FA and GGBFS compared to the control mix. The research underscores the need for a thoughtful selection of supplementary cementitious materials (SCMs) to maximize the strength properties of slag-based concrete and showcases the potential of FA and GGBFS in enhancing carbonation depth. These findings hold implications for developing sustainable concrete materials for road pavement purposes and provide guidance for concrete design and evaluation. The research project’s primary results can review the minimum SL cement content required for the Transport for NSW (TFNSW) QA Specification 3211 carbonation formulae with the addition of GGBFS and FA.