01779044

Component

https://doi.org/10.1177/03611981211029935

This study investigates the mechanical and physical properties of engineered geopolymer composites (EGCs) consisting of metakaolin (MK) based geopolymer (GP) binder, microsilica sand (MS) or river sand (RS), and polyvinyl alcohol (PVA) fiber. Plain GP matrices and fiber-reinforced composites were studied. Aspects of the material composition evaluated here included binder composition, aggregate type, and fiber content. Compressive strength test results revealed that GP mortars presented greater compressive strength than pure GP binders. Moreover, the addition of PVA fibers produced an important increment in compressive strength while increases in fiber content generally enhanced compressive strength. MS composites tended to produce higher compressive strength than RS composites. While exhibiting low densities (i.e., 1.80–1.94?g/cm3), the composite materials evaluated exceeded the compressive strength of regular concrete (i.e., 30?MPa). Furthermore, the best performing composite presented a compressive strength of 57.5?MPa, thus falling in the category of high-strength concrete. The EGC-like tensile pseudo strain-hardening (PSH) behavior of MK-based GP composites was confirmed by a uniaxial tensile test with MS-composites exhibiting greater tensile strength and ductility compared with RS composites; yet, robust PSH behavior was not achieved mainly because of a lack of proper fiber dispersion. Scanning electron microscopy (SEM) revealed unreacted metakaolin particles in some areas within the geopolymer gel of both GP binders evaluated in this study, suggesting incomplete geopolymerization in the binder. Furthermore, energy dispersive X-ray spectroscopy (EDS) microchemical analysis of a geopolymer gel encountered close agreement between the target composition of the GP binders produced and the actual chemical composition encountered in the specimens evaluated.

Ruwa AbuFarsakh https://orcid.org/0000-0002-3596-864X © National Academy of Sciences: Transportation Research Board 2021.

English

0000-0002-3596-864X

0000-0002-3610-8238

0000-0001-8087-8232

0000-0001-7004-3506

0000-0002-5487-3873

0000-0003-4802-459X

0000-0002-2328-4494

pp 475-491

2021-12

Transportation Research Record: Journal of the Transportation Research Board

Web

References (52)

Chemical composition by material content; Composite materials; Compressive strength; Ductility; Engineered materials; Fiber composites; Geopolymer concrete; Kaolin; Polymer fibers; Sand; Tensile strength

Highways; Materials

TRIS, TRB, ATRI

Aug 12 2021 3:16PM