Physical-Mechanical Behavior of Metakaolin Based Geopolymer Systems Reinforced with Stainless Steel Fibers


Physical-Mechanical Behavior of Metakaolin Based Geopolymer Systems Reinforced with Stainless Steel Fibers

L.R. Caballero, M.D.M. Paiva, E.M.R. Fairbairn, R.D.T. Filho

Abstract. Geopolymers are a promising alternative to ordinary Portland cement (OPC) binders in the manufacture of concrete, as their synthesis generates much less greenhouse gas emissions. Geopolymer binders are subject to drying shrinkage, which can be controlled by decreasing the water to cement ratio and adding inert materials to produce mortars. These systems are also brittle in nature and, therefore, it is important to investigate the fiber reinforcement efficiency under tensile loading. This study is based on typical metakaolin-based geopolymer pastes and mortars, activated with sodium silicate and sodium hydroxide. The aim of the study is to evaluate two metakaolin batches with different contents of crystalline phases, the addition of a fixed natural sand content and different contents of stainless steel fibers and their effect on the physical-mechanical performance of the composites. The geopolymer networks were confirmed by XRD and FTIR characterizations. Microstructure results showed that the geopolymer composites formed a dense and uniform base matrix, with no microvoids and very little Na2CO3 efflorescence. Metakaolin-based geopolymer pastes and mortars presented typical mechanical properties, with uniaxial compressive strengths ranging from 33 to 50 MPa and flexural tensile strength ranging from 3.4 to 10.0 MPa. Finally, the geopolymer binders exhibit similar physical-mechanical performances, despite the crystalline content of the metakaolin. Pure and reinforced geopolymer systems display overall superior mechanical performance, when compared to OPC matrices, especially regarding the maximum strain at failure, suggesting that these systems are suitable to replace OPC systems in structural applications.

Geopolymer, Geopolymer Mortar, Fiber-Reinforced Geopolymer Composite, Metakaolin, Mechanical Properties

Published online , 18 pages
Copyright © 2018 by the author(s)
Published under license by Materials Research Forum LLC., Millersville PA, USA

Citation: L.R. Caballero, M.D.M. Paiva, E.M.R. Fairbairn, R.D.T. Filho, ‘Physical-Mechanical Behavior of Metakaolin Based Geopolymer Systems Reinforced with Stainless Steel Fibers’, Materials Research Proceedings, Vol. 7, pp 295-312, 2018


The article was published as article 27 of the book Non-Conventional Materials and Technologies

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