Microstructure and hardened state properties on pozzolan-containing concrete. (1st June 2017)

• Record Type: Journal Article
• Authors: Paiva, H.; Silva, A.S.; Velosa, A.; Cachim, P.; Ferreira, V.M.
• Is Part Of: Construction & building materials. Volume 140(2017)
• Page Start: 374
• Page End: 384
• Publication Date: 2017-06-01
• Subjects: Concrete -- Metakaolin -- Diatomite -- Microstructure -- SEM/EDS -- Porosity -- Reactivity -- Admixtures; Building materials -- Periodicals; 624.18
• DOI: 10.1016/j.conbuildmat.2017.02.120
• Languages: English
• ISSNs: 0950-0618

Abstract

Highlights: SEM microstructure analysis as a tool to evaluate pozzolan's effects in concrete. Effect of two chemically and physically different pozzolans in concrete behaviour. Comparison of concrete rheology controlled by water or a water reducing admixture. Impact of type of workability control over microstructure and hardened state features. Abstract: The homogeneous state of the concrete in the fresh state has consequences on their properties in the hardened state. The use of pozzolanic concrete must be carefully evaluated, because the physical and chemical differences of each pozzolan have consequences on concrete hardened state properties. In this work, two physical and chemically different pozzolans were used to evaluate the effect on concrete microstructure and its basic hardened state properties. Scanning electron microscopy (SEM) was used and can be an effective tool in the analysis of the microstructure allowing a better understanding of the properties of concrete in hardened state. It allows showing that the differences in the two pozzolans (metakaolin and diatomite) promote different microstructures as well as different final properties of pozzolanic concrete. Moreover, it was also shown that the use of a water reducing agent, to adjust workability instead of water, promotes an improvement in both the microstructure and the hardened state features such as porosity and mechanical strength.