Meta-halloysite to improve compactness in iron-rich laterite-based alkali activated materials

Kaze, Cyriaque Rodrigue; Venyite, Paul; Nana, Achile; Nemaleu, Juvenal Giogetti Deutou; Tchakouté, Hervé K.; Rahier, Hubert; Kamseu, Elie; Melo, Uphie Chinje; Leonelli, Cristina

doi:10.1016/j.matchemphys.2019.122268

Cited by 58 publications

(23 citation statements)

References 45 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…2c), is shifted to low wavenumbers in the range of 993-975 cm −1 and 1003-979 cm −1 for GMHA and GMHR geopolymer series respectively. The shift of this characteristic broad band at low wavenumber confirmed the dissolution of the meta-halloysite and the formation of the geopolymer gel [23]. From literature, this band is often used to determine the degree of polycondensation [32,33].…”

Section: Phases Evolutionmentioning

confidence: 81%

“…On the contrary, kaolinite (Al 2 Si 2 O5(OH) 4 ) is a simple layer aluminosilicate consisting of alternate layers of silica and alumina in tetrahedral and octahedral coordination, respectively [22] and typically occurs in platy form. Thermal treatment of halloysite and kaolinite clays from 550 to 800 °C causes their dehydroxylation resulting respectively in meta-halloysite and meta-kaolinite formation, required for the geopolymer synthesis [5,23]. However, the additional water content to halloysite with respect to kaolinite allows earlier decomposition and dehydroxylation conducing to meta-halloysite at lower temperature.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Mechanical and microstructural properties of geopolymer mortars from meta-halloysite: effect of titanium dioxide TiO2 (anatase and rutile) content

et al. 2020

Self Cite

View full text Add to dashboard Cite

This study aimed to investigate the effect of Titanium Dioxide TiO 2 (anatase and rutile) on mechanical and microstructural properties of meta-halloysite based geopolymer mortars namely GMHA and GMHR series. Meta-halloysite received 2.5, 5.0, 7.5 and 10 wt% of anatase or rutile as addition before calcination and geopolymerization. The raw materials and the end products were characterized using XRD, FTIR, ESEM and MIP analyses. The flexural strength increases from 6.90 to 9.13 MPa and from 6.90 to 12.33 MPa for GMHA and GMHR series respectively. The cumulative pore volume decreases from 102.2 to 84.2 mm 3 g −1 and from 102.2 to 51.3 mm 3 g −1 for GMHA and GMHR products respectively. Both matrices present micrographs with very low capillaries pores and fractured surfaces that confirmed the enhancement of the mechanical properties. It was concluded that TiO 2 in both forms is beneficial for the reduction of porosity and densification of geopolymer matrices. Rutile enabled more compact and denser geopolymer structure compared to anatase. The aforementioned results showed the efficiency of both fine TiO 2 particles to improve the geopolymer network significant for its durability.

show abstract

Section: Phases Evolutionmentioning

confidence: 81%

Section: Introductionmentioning

confidence: 99%

Mechanical and microstructural properties of geopolymer mortars from meta-halloysite: effect of titanium dioxide TiO2 (anatase and rutile) content

et al. 2020

Self Cite

View full text Add to dashboard Cite

show abstract

“…Moreover, the efflorescence is not only an aesthetic problem ( Fig. 1), but it could also have an impact upon the mechanical properties of the material [14][15][16] as well as damaging the protective layer around the steel reinforcement [15,17].…”

Section: Introductionmentioning

confidence: 99%

The impact of the curing process on the efflorescence and mechanical properties of basalt fibre reinforced fly ash-based geopolymer composites

et al. 2020

View full text Add to dashboard Cite

Efflorescence is one of the limitations of the widespread use of geopolymers. This problem is caused by excess unreacted sodium oxide remaining inside materials. Unreacted sodium oxide creates white efflorescence on the surface of the produced material in the form of sodium carbonate heptahydrate Na2CO3∙ 7H2O. It decreases not only the aesthetic value of the final products, but also the mechanical properties of the material. The aim of this article is to analyse the influence of the curing method on the appearance of efflorescence on geopolymer composites reinforced by short basalt, especially on mechanical properties. Class F fly ash from the ‘Skawina’ coal-fired power plant (located in Skawina, Lesser Poland, Poland) was used as raw material for the geopolymerization process. The article compares two methods of curing: typical laboratory conditions (in the air) and samples submerged in water. Three series of fly ash-based geopolymer were cast: basalt fibres were added as 1% and 2% by weight of fly ash and one control series without any fibres. The investigation was performed using visual analysis, including microstructure investigation, and the testing of mechanical properties (compressive strength at ambient temperature) after 28 days.

show abstract

“…The authors of paper [ 23 ] confirmed that the addition of iron strengthened the geopolymeric binder and caused a good cohesion between different particles, and also increased the number of pores. Kaze et al [ 24 ] showed that the Si/Al ratio also has a great influence on the properties of calcined iron-rich laterite-based geopolymers. Davidovits [ 25 ] focused in his research on iron-rich geopolymers, and, at the same time, broke the current trend of iron having a negative impact on the mechanical properties of materials.…”

Section: Introductionmentioning

confidence: 99%

Determination of the Thermal Parameters of Geopolymers Modified with Iron Powder

et al. 2022

View full text Add to dashboard Cite

The paper presents the results of research concerning the influence of a metallic micromaterial on the thermal conductivity λ, specific heat Cp, and thermal diffusivity a of modified geopolymers. Iron oxide in the form of powder with an average granulation of 10 μm was used as the geopolymer-modifying material. The research concerned geopolymer composite samples with metakaolin (activated with potassium silicate) and the addition of iron in amounts ranging from 0.5% to 2.5% in relation to the weight of the metakaolin. Additionally, the samples were modified with sand and fireclay in two different amounts—1:1 and 1:1.2 in relation to the metakaolin. The addition of fireclay caused a decrease in the thermal conductivity of the composites by 30% when compared to the samples with the addition of sand. The lowest value of the thermal conductivity coefficient λ was obtained for the geopolymer with metakaolin and fireclay. When the ratio of these components in the composite was 1:1, the value of thermal conductivity was equal to 0.6413 W/(m·K), while in the case of their ratio being 1:1.2, it was equal to 0.6456 W/(m·K). In the samples containing fireclay, no significant influence of the added iron on the values of thermal conductivity was noticed. In the case of the geopolymer with sand, the effect was noticeable, and it was most visible in the samples containing metakaolin and sand in the ratio of 1:1.2. It was noticed that with an increase in the addition of Fe, the thermal conductivity of the composite increased.

show abstract

Meta-halloysite to improve compactness in iron-rich laterite-based alkali activated materials

Cited by 58 publications

References 45 publications

Mechanical and microstructural properties of geopolymer mortars from meta-halloysite: effect of titanium dioxide TiO2 (anatase and rutile) content

Mechanical and microstructural properties of geopolymer mortars from meta-halloysite: effect of titanium dioxide TiO2 (anatase and rutile) content

The impact of the curing process on the efflorescence and mechanical properties of basalt fibre reinforced fly ash-based geopolymer composites

Determination of the Thermal Parameters of Geopolymers Modified with Iron Powder

Contact Info

Product

Resources

About