Effect of calcium stearate based foam stabilizer on pore characteristics and thermal conductivity of geopolymer foam material

Cui, Yong; Wang, Dongmin; Zhao, Jihui; Li, Duanle; Ng, Serina; Yang, Rui

doi:10.1016/j.jobe.2018.06.002

Cited by 86 publications

(35 citation statements)

References 35 publications

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“…As can be seen from Figure 4, when the addition amount of CFA increases from 0% to 12%, the thermal conductivity of GFs declines from 0.0944 W/(m·K) and 0.0871 W/(m·K), which is close to the results in the present study [36,37]. In fact, the increase of porosity reduces the volume of the skeleton structure, and the thermal conductivity of it is much higher than that of the air within the voids, resulting in a higher thermal insulation effect of the whole GFs [38,39]. Meantime, the addition of CFA improves the rheological property of the geopolymer slurry and makes the pore distribution in the hardened blocks more uniform, which leads to a reduction in the thermal conductivity of GFs.…”

Section: Thermal Conductivitysupporting

confidence: 88%

Fabrication and Fireproofing Performance of the Coal Fly Ash-Metakaolin-Based Geopolymer Foams

Peng

Qin

et al. 2020

Materials

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This paper aims to investigate the influence of coal fly ash (CFA) addition on the fireproof properties of the metakaolin-based geopolymer foams. The physical properties, thermal conductivity and fire resistance of the CFA-metakaolin-based geopolymer foams are discussed. The CFA-metakaolin-based geopolymer foams achieve a dry density between 259.43 kg/m 3 and 349.73 kg/m 3 , a porosity between 71.78% and 72.98%, a thermal conductivity between 0.0871 W/(m·K) and 0.0944 W/(m·K) and a compressive strength between 0.38 MPa and 0.56 MPa, exhibiting better physical properties than that of the porous blocks without CFA addition. It is also found that the CFA addition could decrease the viscous sintering temperature and change the phase compositions of sintering products, resulting in the porous structure deterioration in a certain extent and obvious rise of the final reverse-side temperature during the fire-resistance tests. Fortunately, the conversion of the amorphous geopolymer gel to ceramics has helped to maintain the main skeleton structure stability. The CFA-metakaolin-based geopolymer foams still exhibit excellent fire resistance, and the reverse-side temperatures are always within 250 • C after 3 h fire-resistance tests.

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Section: Thermal Conductivitysupporting

confidence: 88%

Fabrication and Fireproofing Performance of the Coal Fly Ash-Metakaolin-Based Geopolymer Foams

Peng

Qin

et al. 2020

Materials

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“…The effect of calcium stearate in the concrete has been studied intensively by some researchers, e.g., to reduce the permeability [ 14 ], to act as an accelerator and reduce the corrosion rate [ 15 ], to improve absorption in the foamed concrete [ 16 ], and also to reduce the quantity of macroscopic sale pore sized 10–100 µm [ 17 ]. The reduction of water absorption can also be applied in the concrete by adding the superplasticiser as a water reducer [ 18 ].…”

Section: Introductionmentioning

confidence: 99%

Drying Shrinkage of Concrete Containing Calcium Stearate, (Ca(C18H35O2)2), with Ordinary Portland Cement (OPC) as a Binder: Experimental and Modelling Studies

et al. 2020

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This work investigates the effect of calcium stearate (Ca(C18H35O2)2) on concrete shrinkage behaviors by using experimental testing. The test specimens are cubes with each dimension given as 100 × 100 × 285 mm for shrinkage tests and cylinders with 150 mm diameter and 300 mm height for compressive strength tests. The calcium stearate with fractions of 0, 0.1, 0.2, and 0.3% from the weight of cement are used in the tests. The results showed that the shrinkage occurred in amounts of 0.079, 0.062, 0.065, and 0.060 mm for the specimens containing calcium stearate of 0, 0.1, 0.2, and 0.3%, respectively. Moreover, we also perform shrinkage modelling to explore a possibility to incorporate the calcium stearate fraction into the standard concrete shrinkage model. There are three well-known shrinkage models used here, i.e., the Sakata, the Japan Standard and the Bazant-Baweja models, where only the latter one is capable to capture our experimental results very well for different fractions of calcium stearate.

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“…According to the previous experiments by authors [27], the FA-based geopolymers have strong strength at a SiO 2 /Al 2 O 3 and Na 2 O/ Al 2 O 3 molar ratio of 3.1 and 0.7, respectively. In order to study the influence of the water-to-solid ratio (W/S) on properties and pore structure of foam geopolymers, additional H 2 O was added to adjust a mass ratio of W/S from 0.38 to 0.50 at a step of 0.03.…”

Section: Preparation and Synthesis Of Specimenmentioning

confidence: 66%

Effects of Water on Pore Structure and Thermal Conductivity of Fly Ash-Based Foam Geopolymers

Cui

Wang

2019

Advances in Materials Science and Engineering

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e influence of the water-to-solid ratio (W/S) on the viscosity, pore characteristics, bulk density, compressive strength, and thermal conductivity of foamed fly ash-based geopolymers with thermal conductivity less than 0.065 W/(m·K) was investigated, and their properties and cost analysis were also compared with that of foamed ordinary Portland cement (OPC). When the W/S varied from 0.38 to 0.5, the apparent viscosity of geopolymer paste 15 min after the preparation decreased significantly from 168 Pa·s to 6 Pa·s. e increasing W/S ratio contributed to the rise of the number of microcapillaries (φ < 50 nm) and macrocapillaries (50 nm < φ < 50 μm) but contributed to the decline of artificial air pores (φ > 50 μm). e refinement of pore characteristics lowered the 28 d thermal conductivity of foamed geopolymers from 0.06 W/(m·K) to 0.048 W/(m·K). Although the slight increase of total porosity of foamed geopolymers from 89% to 92% with the increase of the W/S ratio weakened their 28 d compressive strength from 0.75 MPa to 0.45 MPa, this strength still meets the Ordinary Portland Cement (OPC) based Foam Insulation Board standard of JC/T2200-2013 (>0.4 MPa for 0.25 g/cm 3 ). e production cost of foamed geopolymers was slightly higher by 1.1-1.5 times than that of foamed OPC. However, considering the more beneficial effect of environmental load reductions and better mechanical and thermal properties of foamed geopolymers than those of foamed OPC, slightly higher cost would be acceptable for practical application.

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Effect of calcium stearate based foam stabilizer on pore characteristics and thermal conductivity of geopolymer foam material

Cited by 86 publications

References 35 publications

Fabrication and Fireproofing Performance of the Coal Fly Ash-Metakaolin-Based Geopolymer Foams

Fabrication and Fireproofing Performance of the Coal Fly Ash-Metakaolin-Based Geopolymer Foams

Drying Shrinkage of Concrete Containing Calcium Stearate, (Ca(C18H35O2)2), with Ordinary Portland Cement (OPC) as a Binder: Experimental and Modelling Studies

Effects of Water on Pore Structure and Thermal Conductivity of Fly Ash-Based Foam Geopolymers

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