Recycled natural wastes in metakaolin based porous geopolymers for insulating applications

Ngouloure, Zénabou N. M.; Naït-Ali, Benoît; Zékeng, S.; Kamseu, E.; Melo, Uphie Chinje; Smith, David Stanley; Leonelli, Cristina

doi:10.1016/j.jobe.2015.06.006

Cited by 39 publications

(10 citation statements)

References 30 publications

(69 reference statements)

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“…where the experimental constants of A and B were determined to be 0.026 and 11.54 for y ash-(FA-) based geopolymer pastes and 0.016 and 3.20 for metakaolin-(MK-) based geopolymer pastes [29], respectively.…”

Section: Resultsmentioning

confidence: 99%

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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Section: Resultsmentioning

confidence: 99%

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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“…The complete disappearance of this band in the IR spectrum of GPC40 is responsible for giving GPC40 the lowest value for the apparent density. The decrease in the values for the apparent density of geopolymer mortars from 1.88 to 1.70 g/cm 3 suggests that rice husk can be used as an additive for producing lightweight geopolymer cements, mortars and concretes. Despite the decrease in these values, they are still high compared to those obtained by Fongang et al [4] and Hassan et al [36].…”

Section: Apparent Densitymentioning

confidence: 99%

“…These foaming agents are expensive, however, and their production is energy intensive and emits greenhouse gases into the atmosphere. In order to alleviate these drawbacks, some researchers such as Ngouloure et al [3] have used waste materials as foaming agents for producing lightweight geopolymer cements which employ recycled natural waste products such as rice husk ash and volcanic ash as foaming agents to prepare metakaolin-based porous geopolymers for insulating applications.…”

Section: Introductionmentioning

confidence: 99%

Microstructure and mechanical, physical and structural properties of sustainable lightweight metakaolin-based geopolymer cements and mortars employing rice husk

Riyap

Bewa

Banenzoué

et al. 2019

Journal of Asian Ceramic Societies

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This work focuses on an in-depth investigation of the formation of pores in the structure of lightweight geopolymer cements and mortars using rice husk as a foaming agent. The hardener used in this study was sodium waterglass. Metakaolin was replaced by 0, 10, 20, 30 and 40 % by mass of husk and the obtained powders were used to produce lightweight geopolymer cements and mortars. The formation of pores in the lightweight geopolymer cements was monitored using X-ray diffractometry and infrared spectroscopy while those in the mortars were assessed using apparent density and compressive strength measurements, mercury intrusion porosimetry and optical and scanning electron microscopy. The values for the compressive strength and apparent density were in the ranges of 28.92-0.75 MPa and 1.88-1.70 g/cm 3 , respectively. The results indicated that the values for the compressive strength and apparent density of geopolymer mortars decreased while those of the cumulative pore volume increased with increases in the metakaolin replacement level. Stereomicroscopic and scanning electron microscopic images showed the presence of rice husk and fibres of rice husk, respectively, in the networks. It was found that rice husk can be used as a foaming agent for producing sustainable lightweight geopolymer mortars.

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“…Thermal conductivity decreases to 0.15 Wm −1 K −1 with an increase in the concentration of the blowing agent. Adding a rice husk ash or volcanic ash to the inorganic polymer composites increases the Si/Al ratio in the pore solution, which reduces the sodium silicate content to produce a suitable porous structure [38].…”

Section: Municipal Solid Waste Into Building Insulation Materialsmentioning

confidence: 99%

Use of municipal, agricultural, industrial, construction and demolition waste in thermal and sound building insulation materials: a review article

Massoudinejad

Amanidaz

Bakhshoodeh

2019

J Environ Health Sci Engineer

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Production and usage of green and sustainable building materials realizes the desire to integrate more biodegradable, natural, recycled, and renewable resources into the construction industry. The aim is to replace traditionally available construction industry materials due to their environmental impacts through air emissions and waste generation. An observed trend is the production of insulation materials by recycling of industrial, agriculture, construction and demolition (C&D), and municipal solid wastes, thus reducing the environmental burdens of these wastes. While thermal insulation is important in saving energy, sound insulation has drawn much attention in recent years. There are various waste materials that have good thermal and sound properties, enabling effective replacement of traditional materials. This review investigates the use of industrial, agricultural, C&D, and municipal solid wastes to produce innovative thermal and acoustic insulating building materials. The performance of these insulating materials, and the influence of several materials parameters (density, thermal conductivity, sound absorption coefficient) on thermal and acoustic performance are reported after a brief description of each material.

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Recycled natural wastes in metakaolin based porous geopolymers for insulating applications

Cited by 39 publications

References 30 publications

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

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

Microstructure and mechanical, physical and structural properties of sustainable lightweight metakaolin-based geopolymer cements and mortars employing rice husk

Use of municipal, agricultural, industrial, construction and demolition waste in thermal and sound building insulation materials: a review article

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