Bio-mechanical efficacy for slag/fly ash-based geopolymer mingled with mesoporous NiO

Abstract

The main target of this research is the fabrication of pre-cast/self-cleaning eco-friendly building materials with adequate mechanical properties to be used in constructions exposed to bacteria, such as hospitals, to prevent the spread of epidemics and diseases. The impact of different doses of mesoporous NiO (MP-NiO) on the compressive strength value of 50 wt%slag+ 50 wt%fly-ash geopolymer paste was studied at different curing regimes. At 28-days of normal curing, the strength values for the modified pastes containing 0%, 0.5%, 1%, and 2% MP-NiO were 47, 62.4, 65.9 and 58.5 MPa, respectively, while these values completely changed under hydrothermal treatment to become 98.6, 104.8, 105.6 and 100.8 MPa, respectively at 6bars for 4hrs. XRD, TGA/DTG, and SEM techniques affirmed the dual effect of MP-NiO and hydrothermal curing in the production of CSHs, CAHs, CASHs, zeolitic phases, nickel-aluminate spinel (NiAl2O4) and calcium-nickel-silicate (CaNiSi2O6) that reinforced the internal microstructure. The self-cleaning test was conducted via the agar diffusion method. High bacterial resistivity was observed in the cases of discs containing 1% mesoporous NiO, whatever the curing conditions, as these discs strongly resisted the growth of Salmonella, K.Pneumonia, and E. Faecalis and the measured inhibition zones around normally cured discs were 44 ± 1, 44 ± 1, and 52 ± 2, respectively while the measured inhibition zones around autoclaved discs were 45 ± 1, 43 ± 1, and 48 ± 2, respectively.

Keywords

• Geopolymer
• Mesoporous NiO
• Hydrothermal curing
• Mechanical properties
• Anti-bacterial activity