Investigation of geopolymers containing fly ash and ground-granulated blast-furnace slag blended by amorphous ratios

Lau, Chee Keong; Rowles, Matthew R.; Parnham, Glenn N.; Htut, Trevor; Ng, Tian Sing

doi:10.1016/j.conbuildmat.2019.06.198

Cited by 56 publications

(18 citation statements)

References 43 publications

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“…It involves the dissolution of aluminum silicate with geological origin substance or industrial waste such as slag, ash, biomass, or red mud in a highly alkaline medium releasing Si and Al species [19]. Numerous studies have elaborated on the geopolymeric formation by the utilization of incinerated municipal solid waste (MSW) ash, namely municipal solid waste bottom ash (MSW-BA) and fly ash (MSW-FA) as a source of solid aluminosilicate [20][21][22][23][24][25]. The composition of the geopolymers consists of a three-dimensional network of free AlO 4 and SiO 4 tetrahedral, which are formed due to the breakdown of Si-O-Si and Si-O-Al bonds.…”

Section: Introductionmentioning

confidence: 99%

Application of geopolymers synthesized from incinerated municipal solid waste ashes for the removal of cationic dye from water

et al. 2020

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In this study, municipal solid waste bottom ash (MSW-BA) and fly ash (MSW-FA) were used as a source of aluminosilicate to prepare geopolymer (GEO) adsorbents (GEO-MSWBA and GEO-MSWFA) for the removal of methylene blue (MB) from water. The effects of temperature, pH, and initial concentration on the MB adsorption onto GEO-MSWBA and GEO-MSWFA were evaluated. The adsorption isotherms parameters and thermodynamics were also determined. Detailed physical and chemical characterizations of the prepared adsorbents were carried out to further understand their impact on MB adsorption. The results from the scanning electron microscopy revealed a uniform granule-sphere like structure on both prepared geopolymers, which would facilitate the MB adsorption onto the adsorbents. The X-ray diffraction allowed observation of the microstructural transformations that occur after the alkaline activation. The surface areas of the GEO-MSWBA and the GEO-MSWFA were recorded as 32.78 m2/g and 4.5 m2/g, respectively. From the Fourier transform infrared, a stretching vibration of the aluminosilicate tetrahedral was observed, which indicated the success of geopolymerization. The prepared geopolymers showed a high capability of MB adsorption from an aqueous solution. The adsorption process was best suited and explained using the Langmuir isotherm model with a maximum adsorption capacity of 666.7 mg/g for the GEO-MSWBA (at 25°C) and 769.2 mg/g for the GEO-MSWFA (at 35°C). The positive value of the enthalpy (ΔHo) for the GEO-MSWBA suggested the reaction favored endothermic reaction while the negative value of entropy (ΔSo) indicated a solid/liquid random interaction. On the other hand, the negative ΔHo value for the GEO-MSWFA indicated the reaction followed an exothermic reaction causing energy to be released, the positive ΔSo value indicated a good affinity at the solid-liquid surface. The overall negative value for Gibbs free energy (ΔGo) for both adsorbents suggested the adsorption was spontaneous and feasible. It was also inferred that n- π interaction, direct and indirect hydrogen bond, and electrostatic interaction between the MB and the prepared geopolymers facilitated the adsorption process. The current study shows that the GEO-MSWBA and the GEO-MSWFA have a great potential of removing MB as a cationic dye from water without performing any sort of laborious pretreatments.

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Section: Introductionmentioning

confidence: 99%

Application of geopolymers synthesized from incinerated municipal solid waste ashes for the removal of cationic dye from water

et al. 2020

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“…This indicates that the addition of natural perlite, at the 40% level, has contributed to the compressive strength development of the synthesized geopolymers, presumably related to the additional reaction resource obtained from the perlite. The increase in the compressive strength with the perlite incorporation was due to the relatively higher SiO 2 /Al 2 O 3 molar ratio and the amorphous nature of perlite compared to pozzolan [1,30,31], which increases the content of reactive silica and alumina in the reaction medium and, consequently, the formation of more geopolymerization products, which could be mainly sodium aluminosilicate hydrate gel (N-A-S-H) due to the low calcium content [30,32]. These results are in accordance with those found by Duan et al, [33], which show the increase in compressive strength of y ash-based geopolymers with increasing silica fume content.…”

Section: Compressive Strength Analysismentioning

confidence: 99%

Experimental study on the synthesis and characterization of volcanic rocks (pozzolan and perlite)-based geopolymers

Aziz

Benzaouak

Bellil

et al. 2021

Preprint

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The geopolymer preparation based on natural pozzolan is a promising route. Thus, improving the physicochemical properties of these geopolymers by adding other volcanic rocks merits investigation. The present work aims to study the effect of perlite addition, as an acidic volcanic rock, on the physico-chemical and microstructural properties of geopolymers based on pozzolan (basic volcanic rock). The perlite proportion varied between 0 and 50%. A mixture of sodium silicate (Na2SiO3) and sodium hydroxide (NaOH) was used as an alkaline activator. The perlite effect on the physico-mechanical properties of the synthesized geopolymers was evaluated by the compressive strength (Rc), P-wave velocity (Vp), bulk density (D), and porosity (P). The microstructural aspects have been explored by X-ray Diffractometry (XRD), Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy (SEM), and Energy-Dispersive X-ray spectroscopy (EDS). The results highlight the possibility of obtaining an eco-efficient geopolymer, with compressive strength of up to 50 MPa at 28 days by partially replacing the pozzolan by 40% of the perlite, due to the formation of more amorphous N-A-S-H type gel. However, the excessive content (over 40%) of perlite had a negative effect on the development of the compressive strength and microstructure of the pozzolan-based geopolymer, which was related to the formation of zeolitic phases in the geopolymer matrix. This study confirms the promise of using pozzolan-perlite-based geopolymers as sustainable building materials, which could significantly promote the development of geo-resources and environmental protection in the construction sector.

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“…The specific gravities of the FA and GGBFS were 2.4 and 3.0. The mix design used in this study was derived from the previous study with the amorphous calcium content reduced to ensure sufficient setting time for casting [ 30 ]. SF was also added to ensure that the concrete strength to exceed 50 MPa for the optimal fibre–matrix anchorage of the fibres.…”

Section: Experimental Investigationmentioning

confidence: 99%

Torsional Behaviour of Steel Fibre Reinforced Alkali Activated Concrete

Lau

Htut²,

Melling³

et al. 2020

Materials

Self Cite

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Nine alkali-activated concrete beams were produced and tested under pure torsional load to failure. The alkali-activated concrete beams were produced with following variables: (i) fibres only, (ii) conventionally reinforced or (iii) a hybrid of both fibres and conventional steel reinforcement. The fibres only beams were found to have approximately 20% higher cracking torque than conventionally reinforced beams. However, fibres only beams were observed to have lower post crack ductility and inconsistent post crack behaviour, in comparison to conventionally reinforced alkali-activated concrete (AAC) beams. On the other hand, the hybrid reinforcements in AAC beams were found to demonstrate more ductile post crack behaviour consistently of the beams tested. Hybrid reinforcement was also shown to have 20% and 25% improvement in cracking and ultimate torque compared to conventionally reinforced, which suggests that it is suitable for industrial applications to improve structure capacity. The ultimate torque results of the beams were compared to an analytical model that considered the contribution of fibres. It was found that the ultimate torque of the hybrid reinforced beam has good correlation with the model but overestimated conventionally reinforced beams.

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Investigation of geopolymers containing fly ash and ground-granulated blast-furnace slag blended by amorphous ratios

Cited by 56 publications

References 43 publications

Application of geopolymers synthesized from incinerated municipal solid waste ashes for the removal of cationic dye from water

Application of geopolymers synthesized from incinerated municipal solid waste ashes for the removal of cationic dye from water

Experimental study on the synthesis and characterization of volcanic rocks (pozzolan and perlite)-based geopolymers

Torsional Behaviour of Steel Fibre Reinforced Alkali Activated Concrete

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