Research

15 pages, 4077 KiB

Open AccessArticle

Carbstone Pavers: A Sustainable Solution for the Urban Environment

by Hadi Kazemi Kamyab, Peter Nielsen, Peter Van Mierloo and Liesbeth Horckmans

Appl. Sci. 2021, 11(14), 6418; https://0-doi-org.brum.beds.ac.uk/10.3390/app11146418 - 12 Jul 2021

Cited by 7 | Viewed by 2545

To reduce CO₂ emissions from the building industry, one option is to replace cement in specific applications with alternative binders. The Carbstone technology is based on the reaction of calcium- and magnesium-containing minerals with CO₂ to form carbonate binders. Mixes of [...] Read more.

To reduce CO₂ emissions from the building industry, one option is to replace cement in specific applications with alternative binders. The Carbstone technology is based on the reaction of calcium- and magnesium-containing minerals with CO₂ to form carbonate binders. Mixes of carbon steel slag and stainless-steel slag, with tailored particle size distributions, were compacted with a vibro-press and subsequently carbonated in an autoclave to produce carbonated steel slag pavers. The carbonated materials sequester 100–150 g CO₂/kg slag. Compressive and tensile splitting strength of the resulting pavers were determined, and the ratio was found to be comparable to that of concrete. The environmental performance of the Carbstone pavers, with an average tensile splitting strength of 3.6 MPa, was found to be in compliance with Belgian and Dutch leaching limit values for construction materials. In addition, leaching results for a concrete mix made with aggregates of crushed Carbstone pavers (simulating the so-called “second life” of pavers) demonstrate that the pavers can be recycled as aggregates in cement-bound products after their product lifetime. Full article

(This article belongs to the Special Issue Eco-Performance of Alternative Binder Systems)

► Show Figures

Figure 1

16 pages, 6650 KiB

Open AccessFeature PaperArticle

Durability of Ternary Cements Based on New Supplementary Cementitious Materials from Industrial Waste

by Isabel Fuencisla Sáez del Bosque, María Isabel Sánchez de Rojas, Gabriel Medina, Sara Barcala and César Medina

Appl. Sci. 2021, 11(13), 5977; https://0-doi-org.brum.beds.ac.uk/10.3390/app11135977 - 27 Jun 2021

Cited by 2 | Viewed by 1636

Abstract

Cement-based materials decay with exposure to aggressive agents, a development that raises infrastructure operation and maintenance costs substantially. This paper analyses the inclusion of ultrafine construction and demolition (U_C&DW) and biomass-fuelled power plant (BA) waste as pozzolanic additions to cement in [...] Read more.

Cement-based materials decay with exposure to aggressive agents, a development that raises infrastructure operation and maintenance costs substantially. This paper analyses the inclusion of ultrafine construction and demolition (U_C&DW) and biomass-fuelled power plant (BA) waste as pozzolanic additions to cement in pursuit of more sustainable and eco-respectful binders and assesses the durability of the end materials when exposed to seawater, chlorides (0.5 M NaCl) or sulphates (0.3 M Na₂SO₄). The effect of adding silica fume (SF) at a replacement ratio of 5% was also analysed. Durability was determined using the methodology proposed by Koch and Steinegger, whilst microstructural changes were monitored with mercury intrusion porosimetry (MIP), X-ray diffraction (XRD) and scanning electron microscopy (SEM) for a fuller understanding of decay processes. According to the findings, the new blended cements containing 20%U_C&DW + 10%BA or 20%U_C&DW + 20%BA + 5%SF resist the attack by the aggressive media studied, with a 56-d corrosion index of over 0.7. The composition of the reaction products generated with the attack is essentially the same in OPC and the SCM-bearing materials. The results show that the optimal replacement ratio for SCM is 30%. Full article

(This article belongs to the Special Issue Eco-Performance of Alternative Binder Systems)

► Show Figures

Figure 1

13 pages, 2132 KiB

Open AccessArticle

Pore Size Distribution and Surface Multifractal Dimension by Multicycle Mercury Intrusion Porosimetry of GGBFS and Limestone Powder Blended Concrete

by Yury Villagrán-Zaccardi, Natalia Alderete, Philip Van den Heede and Nele De Belie

Appl. Sci. 2021, 11(11), 4851; https://0-doi-org.brum.beds.ac.uk/10.3390/app11114851 - 25 May 2021

Cited by 9 | Viewed by 2087

Abstract

Eco-friendly concrete mixtures make efficient use of constituents with reduced environmental impact to secure durable structures. Ternary mixes containing Portland cement, ground granulated blast-furnace slag (GGBFS) and limestone powder (LP) have demonstrated a good balance between environmental impact, economic cost and technical performance. [...] Read more.

Eco-friendly concrete mixtures make efficient use of constituents with reduced environmental impact to secure durable structures. Ternary mixes containing Portland cement, ground granulated blast-furnace slag (GGBFS) and limestone powder (LP) have demonstrated a good balance between environmental impact, economic cost and technical performance. The pore structure of cement-based materials determines the transport of species; hence its description is a valuable tool for predicting their durability performance. In this paper, textural analysis of the pore structure of Portland cement concrete and GGBFS and limestone powder blended concrete is assessed by multicycle mercury intrusion porosimetry (MIP). Results from three intrusion-extrusion cycles were used for determining pore volume, size distribution and surface multifractal dimension. The hysteresis during the experiments is mainly explained by the combined effects of ink-bottle pores and different contact angles for the intrusion and retraction. The analysis of the surface multifractal dimension of the pore structure showed no significant effects of GGBFS and limestone powder on the pore wall texture of concrete samples. The outcome depicts the advantages of using multiple intrusion-extrusion cycles during MIP experiments, as well as the effect of 35 wt.% GGBFS, 25 wt.% GGBFS + 10 wt.% LP, and 25 wt.% of LP, on concrete pore structure. Full article

(This article belongs to the Special Issue Eco-Performance of Alternative Binder Systems)

► Show Figures

Figure 1

25 pages, 6416 KiB

Open AccessArticle

Use of Treated Non-Ferrous Metallurgical Slags as Supplementary Cementitious Materials in Cementitious Mixtures

by Asghar Gholizadeh Vayghan, Liesbeth Horckmans, Ruben Snellings, Arne Peys, Priscilla Teck, Jürgen Maier, Bernd Friedrich and Katarzyna Klejnowska

Appl. Sci. 2021, 11(9), 4028; https://0-doi-org.brum.beds.ac.uk/10.3390/app11094028 - 28 Apr 2021

Cited by 12 | Viewed by 2426

Abstract

This research investigated the possibility of using metallurgical slags from the copper and lead industries as partial replacement for cement. The studied slags were fayalitic, having a mainly ferro-silicate composition with minor contents of Al₂O₃ and CaO. The slags were [...] Read more.

This research investigated the possibility of using metallurgical slags from the copper and lead industries as partial replacement for cement. The studied slags were fayalitic, having a mainly ferro-silicate composition with minor contents of Al₂O₃ and CaO. The slags were treated at 1200–1300 °C (to reduce the heavy metal content) and then granulated in water to promote the formation of reactive phases. A full hydration study was carried out to assess the kinetics of reactions, the phases formed during hydration, the reactivity of the slags and their strength activity as supplementary cementitious material (SCM). The batch-leaching behaviour of cementitious mixtures incorporating treated slags was also investigated. The results showed that all three slags have satisfactory leaching behaviour and similar performance in terms of reactivity and contribution to the strength development. All slags were found to have mediocre reactivity and contribution to strength, especially at early ages. Nonetheless, they passed the minimum mechanical performance requirements and were found to qualify for use in cement. Full article

(This article belongs to the Special Issue Eco-Performance of Alternative Binder Systems)

► Show Figures

Figure 1

16 pages, 16032 KiB

Open AccessArticle

Detoxified Spent Pot Lining from Aluminum Production as (Alumino-)Silicate Source for Composite Cement and AutoClaved Aerated Concrete

by Arne Peys, Mateja Košir, Ruben Snellings, Ana Mladenovič and Liesbeth Horckmans

Appl. Sci. 2021, 11(8), 3715; https://0-doi-org.brum.beds.ac.uk/10.3390/app11083715 - 20 Apr 2021

Cited by 6 | Viewed by 3279

Abstract

New sources of supplementary cementitious materials (SCMs) are needed to meet the future demand. A potential new source of SCM is spent pot lining, a residue from aluminum production. The present work showed that the refined aluminosilicate part of spent pot lining (SPL) [...] Read more.

New sources of supplementary cementitious materials (SCMs) are needed to meet the future demand. A potential new source of SCM is spent pot lining, a residue from aluminum production. The present work showed that the refined aluminosilicate part of spent pot lining (SPL) has a moderate chemical reactivity in a cementitious system measured in the R3 calorimetry test, comparable to commercially used coal fly ash. The reaction of SPL led to the consumption of Ca(OH)₂ in a cement paste beyond 7 days after mixing. At 28 and 90 days a significant contribution to strength development was therefore observed, reaching a relative strength, which is similar to composite cements with coal fly ash. At early age a retardation of the cement hydration is caused by the SPL, which should most likely be associated with the presence of trace amounts of NH₃. The spent pot lining is also investigated as silica source for autoclaved aerated concrete blocks. The replacement of quartz by spent pot lining did not show an adverse effect on the strength-density relation of the lightweight blocks up to 50 wt% quartz substitution. Overall, spent pot lining can be used in small replacement volumes (30 wt%) as SCM or as replacement of quartz (50 wt%) in autoclaved aerated concrete blocks. Full article

(This article belongs to the Special Issue Eco-Performance of Alternative Binder Systems)

► Show Figures

Graphical abstract

14 pages, 3866 KiB

Open AccessArticle

Viability of Cupola Slag as an Alternative Eco-Binder and Filler in Concrete and Mortars

by Israel Sosa, Pablo Tamayo, Jose A. Sainz-Aja, Ana Cimentada, Juan Antonio Polanco, Jesús Setién and Carlos Thomas

Appl. Sci. 2021, 11(4), 1957; https://0-doi-org.brum.beds.ac.uk/10.3390/app11041957 - 23 Feb 2021

Cited by 7 | Viewed by 2115

Abstract

Obtaining new materials capable of meeting society’s demands motivates the search for new solutions that are capable of satisfying twofold requirements: respect for the environment and obtaining more durable and resistant materials. Cupola slag is a by-product generated in the process of obtaining [...] Read more.

Obtaining new materials capable of meeting society’s demands motivates the search for new solutions that are capable of satisfying twofold requirements: respect for the environment and obtaining more durable and resistant materials. Cupola slag is a by-product generated in the process of obtaining ductile iron. When the slag undergoes rapid cooling, its vitrification is favored, leaving the silica in an amorphous structure and, thus, susceptible to reacting. Through reaction, the slag can develop cementing properties and cement can consequently be partially replaced with residue, providing savings in economic and environmental costs compared to traditional hydraulic binders. In this study, the physical and chemical properties of cupola slag and its recovery process are analyzed. Mortars that incorporate traditional admixtures (fly ash and limestone filler) have been manufactured and consistency and mechanical properties have been compared with mortars that incorporate cupola slag admixture. Mortars have also been manufactured with normalized sand and with Portland cement replacements (0, 10, 20, and 30% by weight) with cupola slag, and both the consistency and the mechanical properties have been compared at 7, 28, 60, and 90 days. The results obtained show the suitability of cupola slag as a binder and as an admixture, with respect to the traditional ones, and how the mechanical properties tend to converge for all of the replacement levels characterized, for ages close to 90 days of age. Full article

(This article belongs to the Special Issue Eco-Performance of Alternative Binder Systems)

► Show Figures

Figure 1

14 pages, 1831 KiB

Open AccessFeature PaperArticle

Reactivity Assessment of Modified Ferro Silicate Slag by R³ Method

by Pithchai Pandian Sivakumar, Stijn Matthys, Nele De Belie and Elke Gruyaert

Appl. Sci. 2021, 11(1), 366; https://0-doi-org.brum.beds.ac.uk/10.3390/app11010366 - 01 Jan 2021

Cited by 16 | Viewed by 2383

Abstract

Traditional methods to track the reactivity of supplementary cementitious materials (SCMs) and their contribution to the hydration mechanism mostly use Portland Cement (PC) as an activator. Alternatively, a novel method to assess the reactivity of SCMs called R³ was recently presented. This [...] Read more.

Traditional methods to track the reactivity of supplementary cementitious materials (SCMs) and their contribution to the hydration mechanism mostly use Portland Cement (PC) as an activator. Alternatively, a novel method to assess the reactivity of SCMs called R³ was recently presented. This novel method uses lab grade chemicals such as portlandite (CH), K₂SO₄, KOH, and CaCO₃ to activate the SCM by resembling the pH of the alkaline pore solution created by PC. By using this method, the reactivity of the SCM can be easily quantified from measured heat release, bound water content, and CH consumption. The primary objective of the current study is to apply the novel methodology to analyze the reactivity of Modified Ferro Silicate (MFS) Cu slag benchmarked against siliceous fly ash (FA), ground granulated blast-furnace slag (GGBFS), and inert quartz filler. GGBFS showed the highest cumulative heat release and bound water content due to its latent hydraulic behavior. Determination with XRD analysis of the major phase of the R³ model MFS slag paste showed the participation of Fe in the hydration mechanism by forming Fe-AFm. R³ paste with GGBFS showed the presence of hydrotalcite/Al-AFm, whereas FA showed the presence of ettringite (AFt) as their crystalline reaction products. The experiments also indicate that the MFS slag acts as a reactive pozzolanic material with an acceptable performance in heat release, bound water content, and CH consumption, and can be used as SCM to make concrete. With the possibility of using MFS slag as SCM to replace part of PC, sustainability and circular economy can be fairly well achieved. Full article

(This article belongs to the Special Issue Eco-Performance of Alternative Binder Systems)

► Show Figures

Figure 1

24 pages, 5017 KiB

Open AccessArticle

Sustainable and Durable Performance of Pozzolanic Additions to Prevent Alkali-Silica Reaction (ASR) Promoted by Aggregates with Different Reaction Rates

by Esperanza Menéndez, Miguel Ángel Sanjuán, Ricardo García-Roves, Cristina Argiz and Hairon Recino

Appl. Sci. 2020, 10(24), 9042; https://0-doi-org.brum.beds.ac.uk/10.3390/app10249042 - 17 Dec 2020

Cited by 16 | Viewed by 2611

Abstract

The increased use of industrial wastes and by-products to produce concretes and blended cements is a lever to achieve carbon neutrality. Furthermore, they could improve their durability. Some pozzolanic additions can minimize the alkali-silica reaction (ASR), which is a well-known deleterious process that [...] Read more.

The increased use of industrial wastes and by-products to produce concretes and blended cements is a lever to achieve carbon neutrality. Furthermore, they could improve their durability. Some pozzolanic additions can minimize the alkali-silica reaction (ASR), which is a well-known deleterious process that occurs between some reactive aggregates and the alkaline pore solution found in mortars and concretes. This work quantifies the efficiency of four pozzolanic materials (natural pozzolan, P, siliceous coal fly ash, V, silica fume, D, and blast-furnace slag, S) assessed by means of compressive strength testing, open porosity, ASR-expansion measurements, and SEM microscopy. Accelerated expansion tests were performed in mortar bars with a cement/sand ratio of 1/2.25 and a water/cement ratio of 0.47, two reactive aggregates and a non-reactive one. The major contributions of this paper are: (i) The more aggregate reactivity is, the higher ASR mitigation level was found when additions were added and (ii) The best additions for ASR inhibition are silica fume and fly ash. Full article

(This article belongs to the Special Issue Eco-Performance of Alternative Binder Systems)

► Show Figures

Figure 1

Journal Menu

Journal Browser

Eco-Performance of Alternative Binder Systems

Share This Special Issue

Special Issue Editors

Special Issue Information

Keywords

Published Papers (8 papers)

Research

Further Information

Guidelines

MDPI Initiatives

Follow MDPI