Performance, radiation shielding, and anti-fungal activity of alkali-activated slag individually modified with zinc oxide and zinc ferrite nano-particles
“…Besides the original crystalline phases of FS (fayalite and magnetite), calcite (2.8%) has been identified in AAFS-BFS, which is attributed to the carbonation of the samples during curing. Simultaneously, the formation of andradite (2%) is mainly due to the interaction between dissolved Fe in FS and calcium silicate phases in BFS, similar to those reported in the literature [44]. Meanwhile, it was observed that the initial crystalline reflections present in FS and LS were also present in the alkali-activated samples of AAFS-LS.…”
“…Besides the original crystalline phases of FS (fayalite and magnetite), calcite (2.8%) has been identified in AAFS-BFS, which is attributed to the carbonation of the samples during curing. Simultaneously, the formation of andradite (2%) is mainly due to the interaction between dissolved Fe in FS and calcium silicate phases in BFS, similar to those reported in the literature [44]. Meanwhile, it was observed that the initial crystalline reflections present in FS and LS were also present in the alkali-activated samples of AAFS-LS.…”
Experiments on the development and properties of aerated concrete based on alkali-activated slag cement (AASC) and using Zn powder (ZP) as a gas agent were carried out. The experiments were designed for water-binding material (w/b) ratios of 0.35 and 0.45, curing temperatures of 23 ± 2 °C and 40 ± 2 °C, and ZP of 0.25%, 0.50%, 0.75%, and 1.0%. ZP generates hydrogen (H2) gas in AASC to form pores. At a w/b of 0.35, the curing temperature had little effect on the pore size by ZP. However, a w/b of 0.45 showed a clear correlation that the pore diameter increased as the curing temperature increased. The low w/b of 0.35 showed a small change in the pore size according to the curing temperature due to the faster setting time than 0.45 and the increased viscosity of the paste. Therefore, at a termination time exceeding at least 60 min and a w/b of 0.45 or more, it was possible to increase the size and expansion force of the pores formed by the ZP through the change of the curing temperature. ZP showed applicability to the manufacture of AASC-based aerated concrete, and the characteristics of foaming according to the curing temperature, w/b ratio, and ZP concentration were confirmed.
“…The mass loss of this peak after 3 and 7 days of hydration is 6.9%, and 7.2%, respectively. The endotherm that appeared at 505 °C is correlated to the dehydration of CH (portlandite) 4 , 59 . The mass loss of this peak is 2.1% and 2.8% after 3 and 28 days of hydration, respectively.…”
Section: Resultsmentioning
confidence: 97%
“…The double peak present at 720 and 780 °C is ascribed to the degradation of calcium carbonates with different crystallinity, because of the carbonation of the specimens during its handling. The% mass loss values of these peaks are varied according to the degree of crystallinity and the degree of carbonation 51 , 59 . Figure 15 TGA/DTG thermograms of hardened specimens made from mix A at ( a ) 7 days and ( b ) 28 days hydration.…”
This study focused on investigating the possibility of using different ratios (5, 10, 15 mass%) of recycled alum sludge (RAS) as partial replacement of ordinary Portland cement (OPC), to contribute to solving the problems encountered by cement production as well as stockpiling of large quantities of water-treated sludge waste. MnFe2O4 spinel nanoparticles (NMFs) were used to elaborate the mechanical characteristics and durability of different OPC-RAS blends. The outcomes of compressive strength, bulk density, water absorption, and stability against firing tests fastened the suitability of utilization of RAS waste for replacing OPC (maximum limit 10%). The inclusion of different doses of NMFs nanoparticles (0.5, 1 and 2 mass %) within OPC–RAS pastes, motivates the configuration of hardened nanocomposites with improved physico-mechanical characteristics and stability against firing. Composite made from 90% OPC–10% RAS–0.5% NMFs presented the best characteristics and consider the optimal choice for general construction applications. Thermogravimetric analysis (TGA/DTG), X-ray diffraction analysis (XRD), and scanning electron microscope (SEM) techniques. affirmed the positive impact of NMFs particles, as they demonstrated the formation of enormous phases as ilvaite (CFSH), calcium silicate hydrates (CSHs), MnCSH, Nchwaningite [Mn2 SiO3(OH)2 H2O], [(Mn, Ca) Mn4O9⋅3H2O], calcium aluminosilicate hydrates (CASH), Glaucochroite [(Ca, Mn)2SiO4, and calcium ferrite hydrate (CFH). These hydrates boosted the robustness and degradation resistance of the hardened nanocomposites upon firing.
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