Compressive strength and microstructural characteristics of class C fly ash geopolymer

Guo, Xiaolu; Shi, Huisheng; Dick, Warren A.

doi:10.1016/j.cemconcomp.2009.11.003

Cited by 637 publications

(222 citation statements)

References 15 publications

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“…Geopolymers has been recognized as fire and acid resistant material, and show high early compressive strength similarly with Portland cement [2][3][4][5][6]. The excellent properties of geopolymers have placed these materials suitable to be used as structural materials [6].…”

Section: Introductionmentioning

confidence: 99%

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Development of Hybrid Composite Rice Husk Ash (RHA)–Geopolymer for Bricks Bearing Buildings

2017

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Abstract. The aim of this study is to synthesize hybrid composite rice husk ash (RHA)-geopolymer as materials for bricks bearing buildings application. Class-C fly ash was used as raw material and rice husk ash (RHA) taken directly from the field, washed and dried at 100 o C for 4 hours. Geopolymers were synthesized through alkali activation method at 60°C for 1 hour with its molar oxide ration of SiO 2 /Al 2 O 3 = 3.0, Na 2 O/SiO 2 = 0.2, and H 2 O/Na 2 O = 10. There were three series of samples produced by mixing fly ash with addition of 5%, 10% and 15% RHA (relative to the mass of fly ash). The samples were tested after 7 days. The highest compressive strength were 26 MPa which is reached by samples containing 10% RHA. The fire resistance measurement showed that the addition of RHA improved fire retardancy of geopolymers. The samples were immersed in 1 M H 2 SO 4 solution for 4 days for acid resistance examination. The X-Ray Diffraction was performed to examine the chemical compositions of the samples before and after the test took place. Scanning Electron Microscopy (SEM) was performed to examine the morphology of these samples surfaces. The addition of 10% RHA in geopolymer showed its excellent properties in terms of mechanical strength, thermal properties, and acid resistance. The study suggests that hybrid composite RHA-geopolymer and can be developed as bricks bearing buildings.

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Section: Introductionmentioning

confidence: 99%

“…On the other hand, the needs to substitute the use of Portland cement have been increasing in recent decades. The production of Portland cement has been recognizing as one of the main contributor of greenhouse effect [1][2][3]. One of the promising environmentally friendly materials is geopolymers [4].…”

Section: Introductionmentioning

confidence: 99%

Development of Hybrid Composite Rice Husk Ash (RHA)–Geopolymer for Bricks Bearing Buildings

2017

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“…In terms of energy requirements, alkali-activated binders require 70% less when compared to Portland cement [8]. The most interesting aspect of alkali-activated binders is that the aluminosilicate sources that have been researched are usually residues [9,10], whereas one ton of Portland cement requires 2.8 tons of non-renewable raw material (clay and calcium carbonate, among others) [11]. In addition to the environmental advantages, the technological benefits of alkali-activated binders are their high compressive strength and durability, which are similar to or better than the characteristics of Portland cement [12].…”

Section: Introductionmentioning

confidence: 99%

Study of the binary system fly ash/sugarcane bagasse ash (FA/SCBA) in SiO2/K2O alkali-activated binders

Castaldelli

Moraes

Akasaki

et al. 2016

Fuel

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Due environmental problems related to Portland cement consumption, many studies have been performed to diminish its use. One solution is the development of alkali-activated binders, which can decrease CO 2 emissions and energy consumption by 70% when compared to Portland cement production. In addition, an alkali-activated binder presents mechanical properties similar to Portland cement mixtures, which turns into an interesting material in civil construction. Aluminosilicate-based materials are important raw materials to produce the alkali-activated binders. Therefore, two residues are presented as an aluminosilicate source in this study: fly ash (FA) and sugarcane bagasse ash (SCBA). Both residues were obtained from a combustion process to generate energy, the former from coal and the latter from the bagasse of the sugarcane industry. In addition, the alkaline activating solution is an important factor to achieve improved mechanical properties. In this context, this study investigated the influence of four different SiO 2 /K 2 O molar ratios (0, 0.36, 0.75 and 1.22) in the activating solution with a constant water content, and three FA/SCBA binder proportions (75/25, 50/50 and 25/75). Microstructural characterization was carried out by X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy, mercury intrusion porosimetry, pH and electrical conductivity measurements to study the evolution of the reaction process. The compressive strength of mortars was assessed in order to determine the optimum SiO 2 /K 2 O molar ratio and FA/SCBA ratio. The tests showed that a SiO 2 /K 2 O molar ratio of 0.75 and FA/SCBA proportion of 75/25 provided the best mechanical properties.

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“…The peak of very weak intensity at 2360 cm -1 represents the stretching and deformation vibration of O-H and H-O-H groups from weakly-bound water molecules adsorbed on the surface or situated between the rings of the geopolymeric products [33]. …”

Section: Resultsmentioning

confidence: 99%

Basic Physical – Mechanical Properties of Geopolymers Depending on the Content of Ground Fly Ash and Fines of Sludge

Sičáková

Števulová

2017

Selected Scientific Papers - Journal of Civil Engineering

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The binding potential of fly ash (FA) as a typical basic component of building mixtures can be improved in mechanical way, which unfolds new possibilities of its utilization. This paper presents the possibilities of preparing the geopolymer mixtures based on ground (d m = 31.0 µm) FA, used in varying percentages to the original (unground; d m = 74.1 µm) one. As a modification, fine-grain sludge from the process of washing the crushed aggregates was used as filler in order to obtain mortar-type material. The basic physical-mechanical properties of mixtures are presented and discussed in the paper, focusing on time dependence. The following standard tests were executed after 2, 7, 28, and 120 days: density, total water absorption, flexural strength, and compressive strength. Ground FA provided for positive effect in all tested parameters, while incorporation of fine portion of sludge into the geopolymer mixture does not offer a significant technical profit. On the other hand, it does not cause the decline in the properties, so the environmental effect (reduction of environmental burden) can be applied through its incorporation into the geopolymer mixtures.

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Compressive strength and microstructural characteristics of class C fly ash geopolymer

Cited by 637 publications

References 15 publications

Development of Hybrid Composite Rice Husk Ash (RHA)–Geopolymer for Bricks Bearing Buildings

Development of Hybrid Composite Rice Husk Ash (RHA)–Geopolymer for Bricks Bearing Buildings

Study of the binary system fly ash/sugarcane bagasse ash (FA/SCBA) in SiO2/K2O alkali-activated binders

Basic Physical – Mechanical Properties of Geopolymers Depending on the Content of Ground Fly Ash and Fines of Sludge

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