Aggregates Obtained by Alkali Activation of Fly Ash: The Effect of Granulation, Pelletization Methods and Curing Regimes

Rudić, Ognjen; Ducman, Vilma; Malešev, Mirjana; Радоњанин, Властимир; Draganić, Suzana; Šupić, Slobodan; Radeka, Miroslava

doi:10.3390/ma12050776

Cited by 10 publications

(5 citation statements)

References 42 publications

(62 reference statements)

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“…The strongest band was Si-H at 1350-1450 cm −1 due to depolymerization. The Si-H bands increased in RCA-UNS 30% samples likely [49,50]. The changes in Si-O-Si transmittance band at 750-800 cm -1 indicate that a secondary C-S-H was formed, which has also been reported in other research [23,51].…”

Section: Fourier Transform Infrared (Ft-ir) Graphs Of Samplessupporting

confidence: 82%

Studying the C–H Crystals and Mechanical Properties of Sustainable Concrete Containing Recycled Coarse Aggregate with Used Nano-Silica

et al. 2021

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The present study aims to replace 30%, 40%, and 50% of the natural coarse aggregate (NCA) of concrete with recycled coarse aggregate containing used nano-silica (RCA-UNS) to produce a new sustainable concrete. Three groups of concrete are made and their mechanical properties and microstructure are studied. In the first group, which was the control group, normal concrete was used. In the second group, 30%, 40%, and 50% of the NCA were replaced with coarse aggregate obtained from crushed concrete of the control samples and with 0.5% nano-silica as filler. In the third group, 30%, 40%, and 50% of the concrete samples’ NCA were replaced with aggregates obtained from 90-day crushed samples of the second group. Water absorption, fresh concrete slump, and compressive strength of the three groups were investigated and compared through scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) tests. The results show that the third group’s compressive strengths increased by 12.8%, 10.9%, and 10% with replacing 30%, 40%, and 50% of NAC with RCA-NS at 28 days compared to the control samples, respectively. This could be due to the secondary production of calcium silicate hydrate due to the presence of new cement paste. The third group’s microstructure was also improved due to the change in the C–H and the production of extra C–S–H. Therefore, the hydration of cement with water produces C–H crystals while reactions are induced by recycled aggregate containing used nano-silica.

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Section: Fourier Transform Infrared (Ft-ir) Graphs Of Samplessupporting

confidence: 82%

Studying the C–H Crystals and Mechanical Properties of Sustainable Concrete Containing Recycled Coarse Aggregate with Used Nano-Silica

et al. 2021

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“…The degree of the reaction was analysed using Fourier-transform infrared spectroscopy (FTIR, Perkin Elmer Spectrum two, Kentucky, USA), a technique used to obtain an infrared spectrum of AAM solid products [26].…”

Section: Experimental Methodsmentioning

confidence: 99%

The Potential of Ladle Slag and Electric Arc Furnace Slag use in Synthesizing Alkali Activated Materials; the Influence of Curing on Mechanical Properties

et al. 2019

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Alkali activation is studied as a potential technology to produce a group of high performance building materials from industrial residues such as metallurgical slag. Namely, slags containing aluminate and silicate form a useful solid material when activated by an alkaline solution. The alkali-activated (AA) slag-based materials are promising alternative products for civil engineering sector and industrial purposes. In the present study the locally available electric arc furnace steel slag (Slag A) and the ladle furnace basic slag (Slag R) from different metallurgical industries in Slovenia were selected for alkali activation because of promising amorphous Al/Si rich content. Different mixtures of selected precursors were prepared in the Slag A/Slag R ratios 1/0, 3/1, 1/1, 1/3 and 0/1 and further activated with potassium silicate using an activator to slag ratio of 1:2 in order to select the optimal composition with respect to their mechanical properties. Bending strength of investigated samples ranged between 4 and 18 MPa, whereas compressive strength varied between 30 and 60 MPa. The optimal mixture (Slag A/Slag R = 1/1) was further used to study strength development under the influence of different curing temperatures at room temperature (R. T.), and in a heat-chamber at 50, 70 and 90 °C, and the effects of curing time for 1, 3, 7 and 28 days was furthermore studied. The influence of curing time at room temperature on the mechanical strength at an early age was found to be nearly linear. Further, it was shown that specimens cured at 70 °C for 3 days attained almost identical (bending/compressive) strength to those cured at room temperature for 28 days. Additionally, microstructure evaluation of input materials and samples cured under different conditions was performed by means of XRD, FTIR, SEM and mercury intrusion porosimetry (MIP).

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“…The asymmetrical stretching vibration of the Si-O bond was seen at 1010 cm −1 [43]. The bands at approximately 600 cm −1 correspond to the Al-O-Si stretching vibrations [65], and the broad peak at approximately 730 cm −1 belongs to the stretching vibration of the hexa-coordinates Al(VI)-OH and Al(VI)-O in the MK, which disappeared during alkalinization [44]. The signal at about 710 cm −1 is due to the bending vibration of the tetracoordinated Al(IV)-O-Si in the cyclic structure.…”

Section: Xpsmentioning

confidence: 96%

Preparation of Porous and Durable Metakaolin-Based Alkali-Activated Materials with Active Metal as Composites for Catalytic Wet Air Oxidation

Christophliemk

Heponiemi

et al. 2022

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Novel porous and durable metakaolin-based alkali-activated materials (MK-AAMs) with active metal as composites were produced to degrade bisphenol A (BPA) in catalytic wet air oxidation (CWAO). Two composite producing processes were employed. The first process consisted of mixing metakaolin (MK), a foaming agent and active metal oxide (CuO, MnO2) in a strongly alkaline solution of K2SiO3 and KOH. Paste was cured under microwave radiation to produce porous CuO and MnO2 composites. A porous blank MK-AAM was produced as described above but without active metal and was used as a reference as well. Cu(OH)2 composite was produced by refluxing a blank MK-AAM in 0.5 M CuSO4 solution for 24 h. The specific surface area (SSA) of the reference, CuO, MnO2, and Cu(OH)2 composites were 36, 53, 61, 89 m2/g, respectively. Mechanical durability was determined in terms of compressive strength and 2.8, 3.4, 3.2, 3.6 MPa were received, respectively. The activity of the reference and the composites were tested in CWAO at 1 MPa and 150 °C for 5 h by using an aqueous model solution of BPA. Under the optimal conditions for CWAO (pressure: 1 MPa; temperature: 150 °C; initial pH 5–6; c[catalyst]: 4.0 g/L) with Cu(OH)2 composite, the BPA and total organic carbon (TOC) conversions of 100% and 53% were reached. During 5 h oxidation, the composites degraded due to the combined effect of erosion (1.5 wt%) and active metal (Cu, Mn) leaching (1.1 wt%, 3.6 wt%). It was proposed that BPA can be degraded energy-efficiently via CWAO into less harmful compounds under mild reaction conditions without losing the desired properties of the composites.

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Aggregates Obtained by Alkali Activation of Fly Ash: The Effect of Granulation, Pelletization Methods and Curing Regimes

Cited by 10 publications

References 42 publications

Studying the C–H Crystals and Mechanical Properties of Sustainable Concrete Containing Recycled Coarse Aggregate with Used Nano-Silica

Studying the C–H Crystals and Mechanical Properties of Sustainable Concrete Containing Recycled Coarse Aggregate with Used Nano-Silica

The Potential of Ladle Slag and Electric Arc Furnace Slag use in Synthesizing Alkali Activated Materials; the Influence of Curing on Mechanical Properties

Preparation of Porous and Durable Metakaolin-Based Alkali-Activated Materials with Active Metal as Composites for Catalytic Wet Air Oxidation

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