Abstract

NAZARI, Ali  and  RIAHI, Shadi. The effects of ZnO₂ nanoparticles on properties of concrete using ground granulated blast furnace Slag as binder. Mat. Res. [online]. 2011, vol.14, n.3, pp. 299-306.  Epub Aug 12, 2011. ISSN 1516-1439.  http://dx.doi.org/10.1590/S1516-14392011005000052.

In the present study, flexural strength together with pore structure, thermal behavior and microstructure of concrete containing ground granulated blast furnace slag with different amount of ZnO₂ nanoparticles has been investigated. Portland cement was replaced by different amounts of ground granulated blast furnace slag and the properties of concrete specimens were investigated. Although it negatively impact the properties of concrete, ground granulated blast furnace slag was found to improve the physical and mechanical properties of concrete up to 45 wt. (%). ZnO₂ nanoparticles with the average particle size of 15 nm were added partially to concrete with the optimum content of 45 wt. (%) of ground granulated blast furnace slag and physical and mechanical properties of the specimens was measured. ZnO₂ nanoparticle as a partial replacement of cement up to 3 wt. (%) could accelerate C-S-H gel formation as a result of increased crystalline Ca(OH)₂ amount at the early age of hydration and hence increase flexural strength of concrete. The increased the ZnO₂ nanoparticles' content more than 3 wt. (%), causes the reduced the flexural strength because of the decreased crystalline Ca(OH)₂ content required for C-S-H gel formation together with unsuitable dispersion of nanoparticles in the concrete matrix. ZnO₂ nanoparticles could improve the pore structure of concrete and shift the distributed pores to harmless and few-harm pores.

Keywords : concrete; ground granulated blast furnace slag; ZnO₂ nanoparticles; flexural strength; TGA; XRD; pore structure.