Thermal conductivity of several geopolymer composites and discussion of their formulation

Samuel, Devon M.; Inumerable, Nathaniel; Stumpf, Andrew J.; Kriven, Waltraud M.

doi:10.1111/ijac.14200

Cited by 11 publications

(9 citation statements)

References 92 publications

(177 reference statements)

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“…In Ashby's chart (Figure 10), which demonstrates common applications of lightweight building materials/ceramics provided in the ANSYS GRANTA EduPack R2021, it can be observed that our geopolymer lightweight composites are within the range of insulating and building materials commonly used [33]. Concerning the values of thermal conductivity reported in the literature in the study [14], we can confirm that our value of about 0.11 W/mK is lower than those recorded for 18 vol% pyrolyzed cork, i.e., 0.56 W/mK. The absence of cork waste pre-treatments and thermal curing of the final composites allowed us to indicate the mixes optimized in this work as sustainable fire-resistant insulation materials with a reduced environmental footprint, when compared to expanded polystyrene systems [34].…”

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confidence: 72%

“…The addition of lightweight waste materials in geopolymers is not studied enough [7,14], even though this type of waste could beneficially affect both the cost of disposal and the future application of geopolymers as insulating materials. Additionally, in the literature, there are only a few cases of the valorization of waste cork used as a lightweight filler or aggregate [10].…”

Section: Discussionmentioning

confidence: 99%

“…To improve fire resistance while maintaining the lightweight nature of the material for non-structural composites, waste cork was added to the matrix. In previous works [10][11][12][13][14], the use of cork has been discussed, but few articles have focused on the use of cork waste in mortars and concrete [15].…”

Section: Introductionmentioning

confidence: 99%

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Waste Cork in Metakaolin–Geopolymer Matrix: Physico-Mechanical Characterization

et al. 2023

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Cork powdery waste (CW) from agglomerated cork caps manufacturing is commonly transported to waste-to-energy plants, although it could be locally exploited for lightweight building materials. The transformation of CW into a geopolymer formulation to obtain a novel composite formulation suitable for insulating panels is presented in this contribution. The geopolymer mix was based on metakaolin added to NaOH and Na silicate solutions, to which 2.4, 4.8 and 9.1 wt% (calculated upon dry metakaolin) of CW in the form of as-received powdery waste were added. No pre-treatments were performed on CW and no thermal curing was conducted for the alkali-activated product that was consolidated at room temperature to improve product sustainability. The insulating panel presented an apparent density of about 1.521 to 0.990 ± 0.001 g/cm3, combined with a total porosity in the range of 35.61 to 56.22 ± 0.003 % for 2.4 to 9.1 wt% of CW, respectively, and this was dependent upon ageing time. The values of its mechanical properties (compressive strength ranged from 2.5 to 1.5 MPa at 28 and 90 days of curing time, complying with UNI EN 998-2) and thermal insulating properties (thermal conductivity around 0.1146 W/mK) indicated that the highest percentage of CW in the formulations, i.e., 9.1 wt%, was suitable to obtain self-standing insulating panels.

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confidence: 72%

Section: Discussionmentioning

confidence: 99%

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Waste Cork in Metakaolin–Geopolymer Matrix: Physico-Mechanical Characterization

et al. 2023

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“…52 Therefore, the enhancement in thermal conductivity of geopolymer facilitates the transfer of temperature from the material interior to the exterior, making it more suitable for heating elements, the grout used in geothermal drilling and molten salt storage system. [51][52][53] F I G U R E 1 0 SEM images of geopolymer: (A) GP-1; (B) GP-2; (C) GP-3; (D) GP-4.…”

Section: Thermal Conductivity Of Geopolymermentioning

confidence: 99%

Electrothermal effect of carbon fiber and graphite reinforced metakaolin‐based geopolymer

Zhang,

Lin,

Chen

et al. 2024

Int J Applied Ceramic Tech

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This paper investigates the influence of carbon fiber and graphite on the cyclic electrothermal performance of geopolymers (inorganic polymers). It was observed that carbon fibers, graphite, and the carbon fiber/graphite composite could form a stable conductive network at low voltage (3 V). However, under high voltages (9 and 12 V), the current of the geopolymer exhibited a peak shape in the first cycle, with higher voltages resulting in larger peak values and decreased conductivity in subsequent cycles. While graphite improved electrical and thermal conductivity, it weakened the microstructure, leading to an increase in microcracks and voids, and a reduction in the strength of geopolymers. The cumulative energy during the electrothermal process was calculated. The failure mechanism of the conductive network in the geopolymer during cyclic electrical heating was explained, highlighting the disruptive effect of gel shrinkage due to water loss on conductive networks.

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“…Some studies have been carried out using waste from the cork industry for its gasification [38] and use as fuel to obtain cork phenolic fraction compounds [39]. Cork particles agglomerated with alkali-activated materials have been studied as substitutes for Portland cement, as thermal and acoustic insulating materials [40] for lightweight mortars, or as additives in geopolymers [41]. Cork powder has been used as a filler for epoxy resins to increase their toughness under impact stress [42,43].…”

Section: Introductionmentioning

confidence: 99%

Slate–Cork Laminate Enhanced with Silicone for Habitat Industry Application

Abenojar,

López de Armentia,

Martínez

2024

Fire

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This study investigates the feasibility of using a composite material comprising slate reinforced with cork sheets for architectural purposes like facades and wall coverings. The research involves the comprehensive characterisation of both slate and cork materials along with the evaluation of the silicone adhesive used in their bonding process, specifically Sikasil® HT from SIKA®. It was found that both slate and cork exhibited low wettability, which was enhanced through cold plasma treatment. Subsequently, a composite sandwich structure was fabricated and subjected to impact testing in a drop tower, along with fire resistance evaluations. The fire tests revealed that when subjected to a flame of 900 °C for 15 min, the slate alone heated rapidly, reaching 500 °C within 3 min on the side opposite to the flame. However, the sandwich structure reached 260 °C on the cork side (opposite to the flame) at 7.5 min, maintaining this temperature until the deterioration or detachment of the cork between 11 and 12 min. This provided insulation and delayed ignition. The sandwich structure maintained its fire resistance due to the insulating properties of cork and the superior thermal resistance of silicone compared to other adhesives up to 260 °C. Overall, the results suggest the potential suitability of this sandwich structure for architectural applications. Its favourable adhesion properties and acceptable fire resistance indicate that it could serve as a viable alternative for construction materials in architectural contexts.

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Thermal conductivity of several geopolymer composites and discussion of their formulation

Cited by 11 publications

References 92 publications

Waste Cork in Metakaolin–Geopolymer Matrix: Physico-Mechanical Characterization

Waste Cork in Metakaolin–Geopolymer Matrix: Physico-Mechanical Characterization

Electrothermal effect of carbon fiber and graphite reinforced metakaolin‐based geopolymer

Slate–Cork Laminate Enhanced with Silicone for Habitat Industry Application

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