Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
3.9
2.5
Journals
Minerals
Special Issues
Alkali-Activated Cements and Concretes
share announcement

Alkali-Activated Cements and Concretes

A special issue of Minerals (ISSN 2075-163X). This special issue belongs to the section "Clays and Engineered Mineral Materials".

Deadline for manuscript submissions: closed (22 April 2022) | Viewed by 15086

Special Issue Editor

Prof. Dr. Elsabe Kearsley

E-Mail Website
Guest Editor
Department Civil Engineering, University of Pretoria, Lynnwood Road, Pretoria 0002, South Africa
Interests: cement; concrete; fly ash; environmental impact

Special Issue Information

Dear Colleagues,

Concrete consisting of sand, stone, water and Portland cement is the most widely used material in the construction of modern infrastructure. Significant strides have been made in the recent past to reduce the impact of cement production by allowing for the inclusion of large volumes of cement extenders such as ground granulated blast furnace slag and fly ash. Many of the problems associated with the use of the limestone-based clicker as the primary component of the cement still need to be addressed.

The aim of this Special Issue on alkali activated cement and concrete is to share the current state of knowledge on reducing the environmental impact of the cement and concrete industry through the use of alkali activation. Articles will focus on aspects including activator types and dosages, waste materials that can be activated, factors affecting the properties of alkali-activated materials, benefits and consequences of using alkali-activated cement and concrete, durability (including acid and thermal resistance), comparing short and long term material properties and environmental impact to that of other building materials currently in use.

Prof. Dr. Elsabe Kearsley
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Minerals is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2400 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • alkali activation
  • fly ash
  • ground granulated blast furnace slag
  • geopolymer
  • acid resistant concrete
  • alkali activated cement
  • alkali activator
  • environmental impact
  • waste materials

Published Papers (7 papers)

Download All Papers
Order results
Result details
Show export options expand_more Show export options expand_less
Select all
Export citation of selected articles as:

Editorial

Jump to: Research

2 pages, 180 KiB  
Editorial
Editorial for Special Issue “Alkali Activated Cements and Concretes”
by Elsabé Kearsley
Minerals 2023, 13(1), 46; https://doi.org/10.3390/min13010046 - 28 Dec 2022
Viewed by 1048
Abstract
Concrete consisting of sand, stone, water and Portland cement is the most widely used material in the construction of modern infrastructure [...] Full article
(This article belongs to the Special Issue Alkali-Activated Cements and Concretes)

Research

Jump to: Editorial

12 pages, 24865 KiB  
Article
Fast-Curing Geopolymer Foams with an Enhanced Pore Homogeneity Derived by Hydrogen Peroxide and Sodium Dodecyl Sulfate Surfactant
by Kyung Won Kim, Hyung Mi Lim, Seog-Young Yoon and Hyunseok Ko
Minerals 2022, 12(7), 821; https://doi.org/10.3390/min12070821 - 28 Jun 2022
Cited by 5 | Viewed by 1916
Abstract
The properties of porous and lightweight ceramic foam that can be cured at room temperature using metakaolin-based geopolymers were studied. A geopolymer slurry was prepared using metakaolin and a potassium-based alkaline medium at room temperature, and the obtained viscous paste was expanded via [...] Read more.
The properties of porous and lightweight ceramic foam that can be cured at room temperature using metakaolin-based geopolymers were studied. A geopolymer slurry was prepared using metakaolin and a potassium-based alkaline medium at room temperature, and the obtained viscous paste was expanded via gaseous methods, by means of the decomposition of peroxide at room temperature. Therefore, geopolymer (GP) foam developed in this study through multivariate geopolymer, foaming agents, and surfactants can be cured at room temperature (within 5 days) without a separate heat treatment process. The homogeneous micropores were obtained through the stabilization of the interface between geopolymer slurry and oxygen gas bubbles generated through the base-catalyzed decomposition of hydrogen peroxide. The porosity was confirmed to be 29% and 54% before and after using sodium dodecyl sulfate (SDS). The compressive strengths and densities were 1.57 MPa and 0.75 g/cm3 for GP foam without SDS, and 3.63 MPa and 0.48 g/cm3 for GP foam with SDS. Through the mercury intrusion porosimetry analysis, the pores were further refined from 100 µm to 30 µm when SDS was used, and at the same time, the variation of pore size was minimized, so that a relatively uniform pore size was maintained. In addition, the thermal conductivity is 0.0803 W/m·K and the pore size is 33.2 μm, which is smaller in pore diameter than the geopolymer containing only hydrogen peroxide. As a result, although the hydrogen peroxide alone sample has excellent thermal conductivity, the use of a surfactant is recommended for fine micropore size control. While reducing the non-uniform distribution of pores and the size of micropores generated through the direct foaming method as an inorganic binder, the possibility of an insulation finish was also confirmed by reducing the weight. Full article
(This article belongs to the Special Issue Alkali-Activated Cements and Concretes)
►▼ Show Figures

Figure 1

23 pages, 10428 KiB  
Article
Characterisation of the Hydration Products of a Chemically and Mechanically Activated High Coal Fly Ash Hybrid Cement
by Grizelda du Toit, Elizabet M. van der Merwe, Richard A. Kruger, James M. McDonald and Elsabé P. Kearsley
Minerals 2022, 12(2), 157; https://doi.org/10.3390/min12020157 - 27 Jan 2022
Cited by 15 | Viewed by 2897
Abstract
Cement companies are significant contributors of the planet’s anthropogenic CO2 emissions. With increased awareness of the substantial volume of CO2 emissions from cement production, a variety of mitigation strategies are being considered and pursued globally. Hybrid cements are deemed to be [...] Read more.
Cement companies are significant contributors of the planet’s anthropogenic CO2 emissions. With increased awareness of the substantial volume of CO2 emissions from cement production, a variety of mitigation strategies are being considered and pursued globally. Hybrid cements are deemed to be technologically viable materials for contemporary construction. They require less clinker than that for ordinary Portland cement, leading to a decrease in CO2 emissions per tonne of hybrid cement manufactured. The hybrids produced in this study consist of 70% siliceous coal fly ash and 30% Portland cement, and combines chemical (sodium sulphate) and mechanical (milling) activation. The aim of this work was to develop a better understanding of the hydration products formed and the resulting effect of activation on these hydration products, of hybrid coal fly ash cement pastes over an extended curing period of up to one year. The results indicated that chemical activation increases the formation of stable, well crystallised ettringite. Chemical activation as well as mechanical activation increased the rate of the pozzolanic reaction between portlandite contained in cement and coal fly ash. The application of combined chemical and mechanical activation definitely resulted in the fastest rate of portlandite consumption, hence an increased rate of the pozzolanic reaction. Full article
(This article belongs to the Special Issue Alkali-Activated Cements and Concretes)
►▼ Show Figures

Graphical abstract

14 pages, 5956 KiB  
Article
Geopolymer Materials Based on Natural Pozzolans from the Moroccan Middle Atlas
by Fadoua Elmahdoubi, Safaa Mabroum, Rachid Hakkou and Mounsif Ibnoussina
Minerals 2021, 11(12), 1344; https://doi.org/10.3390/min11121344 - 30 Nov 2021
Cited by 10 | Viewed by 2566
Abstract
The pozzolans of the Moroccan Middle Atlas are derived from a low explosive volcanism, mostly strombolian. They are mainly composed of olivine and pyroxene, presenting a less homogeneous structure (irregular vesicles). The main target of this project is to study the use of [...] Read more.
The pozzolans of the Moroccan Middle Atlas are derived from a low explosive volcanism, mostly strombolian. They are mainly composed of olivine and pyroxene, presenting a less homogeneous structure (irregular vesicles). The main target of this project is to study the use of natural pozzolans (NP) and metakaolin as precursors for the production of geopolymeric binders. The characterization of raw materials and elaborated geopolymers was carried out to study their mineralogical, chemical, microstructural, and mechanical properties. The studied pozzolans and kaolin were crushed, grinded, and sifted to get a fine grain size diameter of less than 100 µm. Then, they were calcined at 750 °C for 2 h to achieve an amorphous structure, increasing of their reactivity. Geopolymer production consists of mixing pozzolans and metakaolin with different amounts with an alkaline solution of sodium hydroxide and sodium silicates. The mass proportion of metakaolin (MK) used in this study was 10%, 20%, and 30%. In the present work, the amount of metakaolin was added as a source of alumina. The elaborated geopolymers were characterized using XRD, FTIR, TGA, and SEM analyses. The compressive strength was measured at 7, 14, and 28 days. The results showed interesting mechanical proprieties at about 18 MPa at 28 days with the mixture containing 20% MK. The addition of MK showed a significant increase in mechanical properties of the elaborated geopolymer. Meanwhile, the other results confirmed the training of new phases in addition to N-A-S-H gel. All these results indicate that the use of pozzolans in the production of geopolymers could be a great solution for the sustainable management of this mineral resource. Full article
(This article belongs to the Special Issue Alkali-Activated Cements and Concretes)
►▼ Show Figures

Figure 1

13 pages, 2845 KiB  
Article
Cement Substitution in High-Temperature Concrete
by Miroslava Klárová, Jozef Vlček, Michaela Topinková, Jiří Burda, Alexandr Martaus, Ivan Priesol and Jacek Szczerba
Minerals 2021, 11(11), 1161; https://doi.org/10.3390/min11111161 - 21 Oct 2021
Cited by 2 | Viewed by 1480
Abstract
An alternative binder to calcium aluminate cement (CAC) was prepared by the sol-gel method. Chemically pure systems such as tetraethylorthosilicate (SiC8H20O4) and nonahydrate of alumina nitrate (Al(NO3)3·9H2O) were used as major [...] Read more.
An alternative binder to calcium aluminate cement (CAC) was prepared by the sol-gel method. Chemically pure systems such as tetraethylorthosilicate (SiC8H20O4) and nonahydrate of alumina nitrate (Al(NO3)3·9H2O) were used as major raw materials. The manufacturing process of binder via solution is mentioned, and transitions in binder structure as a function of thermal treatment in the range between 85 and 1400 °C are described. Finally, binder efficiency was verified by its application in high-temperature concrete instead of calcium aluminate cement (CAC). Newly developed sol-gel binder was characterized by XRFS quantitative analyses, XRD diffraction, STA-DTA and TG analyses and the BET method. Samples of concrete which were based on natural bauxite raw material showed cold compressive strength of 42 MPa compared to the same material where a conventional CAC was applied, and samples reached cold compressive strength of 44 MPa. Full article
(This article belongs to the Special Issue Alkali-Activated Cements and Concretes)
►▼ Show Figures

Figure 1

11 pages, 3010 KiB  
Article
Hybrid Failure of Cemented Paste Backfill
by Andrew Pan, Mohammadamin Jafari, Lijie Guo and Murray Grabinsky
Minerals 2021, 11(10), 1141; https://doi.org/10.3390/min11101141 - 17 Oct 2021
Cited by 6 | Viewed by 2143
Abstract
The hybrid failure is a coupled failure mechanism under the action of tensile and shear stresses. The failure is critical in cemented paste backfill (CPB) since there are no visible signs prior to the failure. Few studies have been conducted on the coupled [...] Read more.
The hybrid failure is a coupled failure mechanism under the action of tensile and shear stresses. The failure is critical in cemented paste backfill (CPB) since there are no visible signs prior to the failure. Few studies have been conducted on the coupled stress response of CPB. This is most likely due to a lack of suitable laboratory equipment and test procedures. This paper presents a new punching shear apparatus to evaluate the hybrid failure of CPB. We harness two-dimensional finite element analysis (FEA) for supplementing experimental study in providing stress transformation, deformation, and possible failure mechanisms. Our study suggests that the coupled stress is a combination of tensile and shear strength in function of the angle of the frustum. The strengths measured by the coupled stress are comparable to those measured by direct shear and tensile strength tests, in which the strength properties of CPB are curing time and binder content dependent. The FEA results substantiate the effectiveness of proposed model for predicting the hybrid failure of CPB. Full article
(This article belongs to the Special Issue Alkali-Activated Cements and Concretes)
►▼ Show Figures

Figure 1

19 pages, 8239 KiB  
Article
Freeze–Thaw Damage Model of Polypropylene Fiber Reinforced Cement Stabilized Waste Construction Slurry under Uniaxial Action
by Ping Jiang, Lin Zhou, Yue Wang, Biao Qian, Wei Wang, Na Li and Fang Zhang
Minerals 2021, 11(7), 743; https://doi.org/10.3390/min11070743 - 8 Jul 2021
Cited by 11 | Viewed by 1723
Abstract
In order to apply the fiber reinforced cement stabilized waste construction slurry more widely, it is crucial to evaluate its mechanical behavior under freeze and thaw (F–T) cycles. The mechanical properties of fiber cement-modified waste construction slurry (FCMS) under five different F–T cycles [...] Read more.
In order to apply the fiber reinforced cement stabilized waste construction slurry more widely, it is crucial to evaluate its mechanical behavior under freeze and thaw (F–T) cycles. The mechanical properties of fiber cement-modified waste construction slurry (FCMS) under five different F–T cycles were studied using unconfined compressive strength tests. One fixed cement sample with five different types of polypropylene fiber was used in the FCMS. Using the meso random damage model, the two-stage damage stress–strain relationship of FCMS was established using particle swarm optimization (PSO). The results were as follows: (1) The mechanical properties of FCMS at room temperature and in an F–T environment were significantly improved by fiber; (2) The elastic modulus of FCMS decreased in the form of a power function with the increase of F–T cycles; (3) The fitting results of the two-stage F–T damage model based on meso random damage theory were in agreement with the measured data. Full article
(This article belongs to the Special Issue Alkali-Activated Cements and Concretes)
►▼ Show Figures

Figure 1

Show export options expand_more Show export options expand_less
Select all
Export citation of selected articles as:
 
Displaying articles 1-7
Back to TopTop