Effects of kaolin characteristics on the mechanical properties of alkali-activated binders

Alkali-activated materials have the potential to replace Portland cement in certain applications. To better understand these binders’ properties, it is relevant to study their rheological behaviour at early ages, like in the case of Portland cement paste. There are already many studies on the rheological behaviour of these materials in the available literature, using fly ash, metakaolin, and ground granulated blast furnace slag as precursors. However, this study discusses the rheological behaviour, mechanical properties, and porosity of ternary alkali-activated binders based on mining mud waste, waste glass, and metakaolin. The precursor consisted of a volume mix of 70% of tungsten mining waste mud, 15% glass waste, and 15% of metakaolin. The activator was a combination of sodium hydroxide and sodium silicate solution. Five activator/precursor (A/P) ratios (0.37, 0.38, 0.39, 0.40, and 0.4) were studied. The result showed that the activator/precursor ratio affects the rheology of paste and their rheological behaviour fit the Bingham model. The relative yield stress (g) and plastic viscosity (h) increased inversely with the A/P ratio, while the workability increased proportionally. Furthermore, some empirical models are proposed to describe the characteristic of yield stress: plastic viscosity and spread diameter versus the A/P ratio and time with a correlation between the rheological parameters and the spread diameter. The increase in A/P ratio has also followed a decrease in compressive strength in all tested samples for all the ages. As expected, an increase of the porosity accompanied the increase of the A/P ratio.

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Effects of EAF-Slag on alkali-activation of tungsten mining waste: mechanical properties

MATEC Web of Conferences ◽

10.1051/matecconf/201927401003 ◽

2019 ◽

Vol 274 ◽

pp. 01003 ◽

Cited By ~ 1

Author(s):

Naim Sedira ◽

João Castro-Gomes

Keyword(s):

Mechanical Properties ◽

Sodium Silicate ◽

Mining Waste ◽

Alkali Activation ◽

X Ray Diffraction ◽

Eaf Slag ◽

Electric Arc Furnace Slag ◽

Solid Liquid ◽

Alkali Activated Binders ◽

Alkali Activated

The mechanical properties of alkali-activated binders based on blends of tungsten mining waste mud (TMWM) and electric arc furnace slag (EAF-S) were investigated. The synthesis of alkali-activated binders was conducted at 60°C for 24 h with different TMWM/EAF-Slag ratios (90:10, 80:20, 70:30, 60:40, and 50:50 vt.%). Using sodium hydroxide (SH) and sodium silicate (SS) solutions as alkaline activators with ratio solid/liquid 4 by unit of volume, and the sodium silicate to NaOH (SS:SH) ratio of 2:1. The X-ray Diffraction (XRD), mercury intrusion porosimetry (MIP) were determined. The different percentages of the precursors and the alkaline activators were optimised to produce paste samples. The compressive strength of samples with 10 vt.% EAF-Slag was close to 20.7 MPa after 90 curing days. The mechanical properties were further increased up to 30 MPa by increasing the percentage of EAF-Slag to 50 vt.%. This demonstrates a new potential for re-using waste material for various constructional applications.

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Interactions of Various types between Rock and Alkali-Activated Blast Furnace Slag

GeoScience Engineering ◽

10.1515/gse-2017-0004 ◽

2017 ◽

Vol 63 (1) ◽

pp. 22-26

Author(s):

Pavel Mec ◽

Lucie Gembalová

Keyword(s):

Mechanical Properties ◽

Blast Furnace ◽

Blast Furnace Slag ◽

Ordinary Portland Cement ◽

Raw Materials ◽

Matrix Composition ◽

Cement Binder ◽

Alkali Activated Binders ◽

Furnace Slag ◽

Alkali Activated

Abstract Alkali-activated binders (AAB) are very intensively studied materials nowadays. Because of possible usage as secondary raw materials, they can be environmentally efficient. Intensive research is focused especially on binder matrix, composition and its structure. For industrial usage, it is necessary to work with some aggregate for the preparation of mortars and concretes. Due to different structures of alkali-activated binders, the interaction with the aggregate will be different in comparison to an ordinary Portland cement binder. This paper deals with the study of interactions between several types of rocks used as aggregate and alkali-activated blast furnace slag. The research was focused especially on mechanical properties of prepared mortars.

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Experimental Study on Mechanical Properties and Micro-Mechanism of All-Solid-Waste Alkali Activated Binders Solidified Marine Soft Soil

Materials Science Forum ◽

10.4028/www.scientific.net/msf.1036.327 ◽

2021 ◽

Vol 1036 ◽

pp. 327-336

Author(s):

Ya Lei Wu ◽

Jun Jie Yang ◽

Si Chen Li ◽

Man Wang

Keyword(s):

Mechanical Properties ◽

Solid Waste ◽

Coal Fly Ash ◽

Soft Soil ◽

Deformation Modulus ◽

Alkali Activation ◽

Activation Process ◽

Pozzolanic Materials ◽

Alkali Activated Binders ◽

Alkali Activated

Utilizing granulated blast furnace slag (GBFS), coal fly ash (FA), and furfural residue incineration ash (FRIA) as pozzolanic materials, then activated with calcium carbide residue (CCR) respectively to prepare all-solid-waste alkali activated binders (ASW binders). The laboratory tests were performed to research the effects of pozzolanic materials with different reactivity on the macro- and micro- characteristics of solidified marine soft soil. Results show that the mechanical properties and alkali-activation process of ASW binders solidified soil was determined mainly by the reactivity of pozzolanic materials, the higher reactivity of the pozzolanic materials in ASW binders couldn’t change the main hydration products, however, it would accelerate the hydrate reaction. The degree of hydrate reaction increased, the microstructure became denser with the increase of the reactivity of the pozzolanic materials in ASW binders solidified soil, on the macro- side, the strength and deformation modulus of the solidified soil increased, meanwhile, the brittleness of the solidified soil will be more obvious during the deformation resistance process. ASW binders (CCR:GBFS=1:1) solidified soil could reach the strength of cemented soil under the same conditions.

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Mechanical Properties of Alkali Activated Fly Ash Geopolymer Stabilized Expansive Clay

KSCE Journal of Civil Engineering ◽

10.1007/s12205-019-2251-z ◽

2019 ◽

Vol 23 (9) ◽

pp. 3875-3888 ◽

Cited By ~ 6

Author(s):

Anant Lal Murmu ◽

Anamika Jain ◽

Anjan Patel

Keyword(s):

Mechanical Properties ◽

Fly Ash ◽

Expansive Clay ◽

Alkali Activated

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Alkali-Activated Binders Using Bottom Ash from Waste-to-Energy Plants and Aluminium Recycling Waste

Applied Sciences ◽

10.3390/app11093840 ◽

2021 ◽

Vol 11 (9) ◽

pp. 3840 ◽

Cited By ~ 1

Author(s):

Alex Maldonado-Alameda ◽

Jofre Mañosa ◽

Jessica Giro-Paloma ◽

Joan Formosa ◽

Josep Maria Chimenos

Keyword(s):

Bottom Ash ◽

Physicochemical Characterization ◽

Waste To Energy ◽

Promising Alternative ◽

Leaching Potential ◽

Aluminium Recycling ◽

Alkaline Activator ◽

Alkali Activated Binders ◽

Energy Plants ◽

Alkali Activated

Alkali-activated binders (AABs) stand out as a promising alternative to replace ordinary Portland cement (OPC) due to the possibility of using by-products and wastes in their manufacturing. This paper assessed the potential of weathered bottom ash (WBA) from waste-to-energy plants and PAVAL® (PV), a secondary aluminium recycling process by-product, as precursors of AABs. WBA and PV were mixed at weight ratios of 98/2, 95/5, and 90/10. A mixture of waterglass (WG) and NaOH at different concentrations (4 and 6 M) was used as the alkaline activator solution. The effects of increasing NaOH concentration and PV content were evaluated. Alkali-activated WBA/PV (AA-WBA/PV) binders were obtained. Selective chemical extractions and physicochemical characterization revealed the formation of C-S-H, C-A-S-H, and (N,C)-A-S-H gels. Increasing the NaOH concentration and PV content increased porosity and reduced compressive strength (25.63 to 12.07 MPa). The leaching potential of As and Sb from AA-WBA/PV exceeded the threshold for acceptance in landfills for non-hazardous waste.

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The Effect of Different Types of Internal Curing Liquid on the Properties of Alkali-Activated Slag (AAS) Mortar

Sustainability ◽

10.3390/su13042407 ◽

2021 ◽

Vol 13 (4) ◽

pp. 2407

Author(s):

Guang-Zhu Zhang ◽

Xiao-Yong Wang ◽

Tae-Wan Kim ◽

Jong-Yeon Lim ◽

Yi Han

Keyword(s):

Mechanical Properties ◽

Compressive Strength ◽

Deionized Water ◽

Internal Curing ◽

Control Group ◽

Alkali Activated Slag ◽

Different Types ◽

Naoh Solution ◽

Activated Slag ◽

Alkali Activated

This study shows the effect of different types of internal curing liquid on the properties of alkali-activated slag (AAS) mortar. NaOH solution and deionized water were used as the liquid internal curing agents and zeolite sand was the internal curing agent that replaced the standard sand at 15% and 30%, respectively. Experiments on the mechanical properties, hydration kinetics, autogenous shrinkage (AS), internal temperature, internal relative humidity, surface electrical resistivity, ultrasonic pulse velocity (UPV), and setting time were performed. The conclusions are as follows: (1) the setting times of AAS mortars with internal curing by water were longer than those of internal curing by NaOH solution. (2) NaOH solution more effectively reduces the AS of AAS mortars than water when used as an internal curing liquid. (3) The cumulative heat of the AAS mortar when using water for internal curing is substantially reduced compared to the control group. (4) For the AAS mortars with NaOH solution as an internal curing liquid, compared with the control specimen, the compressive strength results are increased. However, a decrease in compressive strength values occurs when water is used as an internal curing liquid in the AAS mortar. (5) The UPV decreases as the content of zeolite sand that replaces the standard sand increases. (6) When internal curing is carried out with water as the internal curing liquid, the surface resistivity values of the AAS mortar are higher than when the alkali solution is used as the internal curing liquid. To sum up, both NaOH and deionized water are effective as internal curing liquids, but the NaOH solution shows a better performance in terms of reducing shrinkage and improving mechanical properties than deionized water.

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Enhancing Density-Based Mining Waste Alkali-Activated Foamed Materials Incorporating Expanded Cork

CivilEng ◽

10.3390/civileng2020029 ◽

2021 ◽

Vol 2 (2) ◽

pp. 523-540

Author(s):

Imed Beghoura ◽

Joao Castro-Gomes

Keyword(s):

Mechanical Properties ◽

Compressive Strength ◽

Pore Size ◽

Physical And Mechanical Properties ◽

Critical Parameters ◽

Porous Structures ◽

Foaming Agent ◽

Al Powder ◽

Highly Porous ◽

Alkali Activated

This study focuses on the development of an alkali-activated lightweight foamed material (AA-LFM) with enhanced density. Several mixes of tungsten waste mud (TWM), grounded waste glass (WG), and metakaolin (MK) were produced. Al powder as a foaming agent was added, varying from 0.009 w.% to 0.05 w.% of precursor weight. Expanded granulated cork (EGC) particles were incorporated (10% to 40% of the total volume of precursors). The physical and mechanical properties of the foamed materials obtained, the effects of the amount of the foaming agent and the percentage of cork particles added varying from 10 vol.% to 40% are presented and discussed. Highly porous structures were obtained, Pore size and cork particles distribution are critical parameters in determining the density and strength of the foams. The compressive strength results with different densities of AA-LFM obtained by modifying the foaming agent and cork particles are also presented and discussed. Mechanical properties of the cured structure are adequate for lightweight prefabricated building elements and components.

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