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15 pages, 5539 KiB

Open AccessArticle

Geopolymeric Composites Containing Industrial Waste Reinforced with Arundo donax Fibers

by Stefania Manzi, Luisa Molari, Maria Chiara Bignozzi, Giulia Masi and Andrea Saccani

Buildings 2024, 14(5), 1191; https://doi.org/10.3390/buildings14051191 - 23 Apr 2024

Viewed by 292

Abstract

Traditional Portland cement-based composites have a great environmental impact. Alkali-activated binders can offer an alternative, particularly if they can be obtained even partially from waste. Two residuals derived from the finishing steps of the traditional ceramic industry have been used as possible polymerizable [...] Read more.

Traditional Portland cement-based composites have a great environmental impact. Alkali-activated binders can offer an alternative, particularly if they can be obtained even partially from waste. Two residuals derived from the finishing steps of the traditional ceramic industry have been used as possible polymerizable sources mixed with metakaolin. Moreover, to contrast the low dimensional stability of alkali-activated materials and their mechanical brittleness, natural fibers derived from the Arundo donax plant have been added to the mortars. The use of renewable natural fibers instead of synthetic ones can contribute a further environmental advantage. The fresh (consistency) and cured (mechanical) properties of composite materials prepared with residuals and metakaolin were analyzed here. For comparison’s sake, a reference set of composite materials not loaded with fibers but with an identical binder/sand and liquid/binder ratio was cast. A room-temperature curing condition was selected that, although inadequate to promote the short-time reactivity of the wastes, has a minimal energy requirement and allows on-site applications. A small-scale decrease in the properties in the compression mode tests was observed in the waste-modified mortars, while the Arundo addition improved their flexural strength and dimensional stability. Full article

(This article belongs to the Special Issue Recent Scientific Developments in Cement-Based and Alternative Materials)

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15 pages, 3356 KiB

Open AccessArticle

Utilization of Waste-Expanded Thermoplastic as a Sustainable Filler for Cement-Based Composites for Greener Construction

by Jaroslav Pokorný, Lucie Zárybnická, Radek Ševčík and Luboš Podolka

Buildings 2024, 14(4), 990; https://doi.org/10.3390/buildings14040990 - 03 Apr 2024

Viewed by 404

Abstract

Plastics represent an integral part of our everyday lives, with various functions from packaging materials to insulation layers in our buildings. Pure expanded polystyrene (EPS) is a good example of a fully recyclable material. However, once polluted with other materials or substances, EPS [...] Read more.

Plastics represent an integral part of our everyday lives, with various functions from packaging materials to insulation layers in our buildings. Pure expanded polystyrene (EPS) is a good example of a fully recyclable material. However, once polluted with other materials or substances, EPS becomes a serious environmental burden. In this work, waste EPS for the production of greener building composites with balanced properties and utility value was investigated. Natural aggregate (2/4 mm) was substituted with corresponding fractions of a thermoplastic alternative in portions of 25, 50, 75, and 100 vol.%. The comprehensive experimental investigation evaluated physical and mechanical properties, heat transport and accumulation, and water absorption characteristics. Due to the uniformly distributed plastic particles in the hardened cement-based matrix, the data revealed an important reduction in the dead weight of produced mortars, which also reduced thermal conductivity by up to 47%. On one hand, lightweight mortars showed partially reduced mechanical resistivity; on the other hand, the EPS bead-modified structure turned out to be effective in liquid water transport reduction. Full article

(This article belongs to the Special Issue Recent Scientific Developments in Cement-Based and Alternative Materials)

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20 pages, 5976 KiB

Open AccessArticle

An Improved Anchorage System for L-Shaped FRP Composites to Enhance the Seismic Response of Beam-Column Joints in a Low-Strength Substandard Reinforced Concrete (RC) Frame

by Waqas Adil, Fayyaz Ur Rahman, Qaisar Ali and Christos G. Papakonstantinou

Buildings 2024, 14(3), 721; https://doi.org/10.3390/buildings14030721 - 07 Mar 2024

Viewed by 559

Abstract

Reinforced concrete buildings are prone to collapse during seismic events due to the brittle shear failure of non-seismic beam-column joints (BCJ). In this study, two one-third scale reinforced concrete (RC) frames incorporating various non-seismic details were tested under lateral cyclic loading. One of [...] Read more.

Reinforced concrete buildings are prone to collapse during seismic events due to the brittle shear failure of non-seismic beam-column joints (BCJ). In this study, two one-third scale reinforced concrete (RC) frames incorporating various non-seismic details were tested under lateral cyclic loading. One of the RC frames was used as control, while the other was strengthened using externally bonded carbon-fiber-reinforced polymer (CFRP) sheets in a L-Shaped configuration with particular attention to anchorage to evade debonding. For the strengthening process, L-shaped CFRP sheets were bonded to the inner face of columns, extended on beams both above and below the joint up to a hinge length. To avert debonding, the L-shaped CFRP sheets were fully wrapped with CFRP sheets around the column, both near the joint and at the end of the sheet. The sheets were also wrapped around the beam, through two slots in the slab that were adjacent to the beam-column interface and at the far end of the sheet. Test results confirmed that the installation of CFRP sheets in an L-shaped configuration altered the brittle-shear failure mechanism of the beam-column joints to a ductile failure by repositioning the hinges away from the columns. Additionally, the proposed anchorage method successfully eradicated the debonding and peel-off of the CFRP sheets. Moreover, strengthening with the CFRP sheets in the L-shaped configuration enhanced the strength and ductility of the RC frame by 45% and 43%, respectively. According to the findings of this study, the application of L-shaped CFRP sheets proved effective in strengthening RC frame structures. Full article

(This article belongs to the Special Issue Recent Scientific Developments in Cement-Based and Alternative Materials)

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19 pages, 3522 KiB

Open AccessArticle

Analyzing the Relationship between Compressive Strength and Modulus of Elasticity in Concrete with Ladle Furnace Slag

by Víctor Revilla-Cuesta, Roberto Serrano-López, Ana B. Espinosa, Vanesa Ortega-López and Marta Skaf

Buildings 2023, 13(12), 3100; https://doi.org/10.3390/buildings13123100 - 13 Dec 2023

Cited by 1 | Viewed by 853

Abstract

The addition of Ladle Furnace Slag (LFS) to concrete modifies its compressive strength and modulus of elasticity and consequently impacts their relationship. This research evaluated both properties at 28, 90, and 180 days in concrete mixes produced with 5%, 10%, and 20% of [...] Read more.

The addition of Ladle Furnace Slag (LFS) to concrete modifies its compressive strength and modulus of elasticity and consequently impacts their relationship. This research evaluated both properties at 28, 90, and 180 days in concrete mixes produced with 5%, 10%, and 20% of two LFS types, both stabilized and non-stabilized. The relationship between them was then analyzed through these experimental results by adopting a statistical approach. A three-way analysis of variance revealed that both properties were affected by LFS differently. Thus, the effect of each LFS content on both features varied depending on its composition and pre-treatment. Furthermore, the effect of the LFS content on the compressive strength was also influenced by the age of the concrete. These facets implied that when analyzing the relationship between both mechanical properties, the monotonic correlations were stronger than the linear ones, reaching values between 0.90 and 1.00. Therefore, the double reciprocal regression models were the most precise ones for expressing the modulus of elasticity as a function of compressive strength. The model accuracy was further enhanced when discriminating based on the LFS type and introducing concrete age as a predictive variable. With all these considerations, the average deviations between the estimated and experimental values of 1–3% and the maximum deviations of 4–7% were reached, as well as R² coefficients of up to 97%. These aspects are central to the further development of LFS concrete models. Full article

(This article belongs to the Special Issue Recent Scientific Developments in Cement-Based and Alternative Materials)

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18 pages, 5797 KiB

Open AccessArticle

Complex Effect of Portland Cement Modified with Natural Zeolite and Ground Glass Mixture on Durability Properties of Concrete

by Dalius Kriptavičius, Giedrius Girskas, Ernestas Ivanauskas and Aleksandrs Korjakins

Buildings 2023, 13(10), 2576; https://doi.org/10.3390/buildings13102576 - 12 Oct 2023

Cited by 1 | Viewed by 733

Abstract

This article analyses the combined effect of a mixture of natural zeolite and ground soda lime silicate glass on the durability properties of concrete. The specimens were prepared by replacing 25% of the cement with a mixture of zeolite and glass at different [...] Read more.

This article analyses the combined effect of a mixture of natural zeolite and ground soda lime silicate glass on the durability properties of concrete. The specimens were prepared by replacing 25% of the cement with a mixture of zeolite and glass at different proportions with zeolite particles of two different sizes and cured for 28 and 90 days. Chloride migration, the depth of water penetration under pressure, and freeze–thaw cycle tests were performed, and compressive strength was determined. The combined effect of the mixture on the composition and microstructure of the cement matrix was studied by analysing the results of XRD, TGA, SEM-BSE, and porosity tests. The test results showed that irrespective of the cement “dilution” effect, the mixture of additives had a beneficial combined effect: increased durability of concrete, a denser structure of the cement matrix, the formation of calcium aluminate hydrates, faster rate, and higher degree of hydration. Full article

(This article belongs to the Special Issue Recent Scientific Developments in Cement-Based and Alternative Materials)

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14 pages, 4942 KiB

Open AccessArticle

The Role of High Carbon Additives on Physical–Mechanical Characteristics and Microstructure of Cement-Based Composites

by Jaroslav Pokorný, Radek Ševčík, Lucie Zárybnická and Luboš Podolka

Buildings 2023, 13(7), 1585; https://doi.org/10.3390/buildings13071585 - 22 Jun 2023

Cited by 4 | Viewed by 866

Abstract

Traditional supplementary cementitious materials (SCMs) have been proven to reduce the negative impact of Portland cement production on the environment. However, the availability of SCMs becomes limited due to their extensive usage. For this reason, our work aimed to investigate the effect of [...] Read more.

Traditional supplementary cementitious materials (SCMs) have been proven to reduce the negative impact of Portland cement production on the environment. However, the availability of SCMs becomes limited due to their extensive usage. For this reason, our work aimed to investigate the effect of partial substitution of ordinary Portland cement (OPC) with two different types of carbon-rich waste powders—biochar (BC) and coal dust (CD), dosed separately up to 10 wt.% of OPC, on the physical, microstructural and mechanical properties of hardened specimens. Obtained data pointed out that replacing OPC with small amounts of BC and CD (not exceeding 5.0 wt.% and 2.5% wt.%, respectively) initiated an increment in mechanical strengths due to a decrease in total open porosity and enhanced formation of hydration products of such composites compared with the reference. Overall, both examined alternatives, if added in appropriate amounts, have the perspective to be effectively applied in cement manufacturing and concrete production, and thus to importantly contribute to the long-term sustainability of the construction industry in view of energy savings, reduced releasing of the greenhouse gasses and mitigating of global climate changes. Full article

(This article belongs to the Special Issue Recent Scientific Developments in Cement-Based and Alternative Materials)

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Review

Jump to: Research

24 pages, 2861 KiB

Open AccessReview

Reusing Ceramic Waste as a Precursor in Alkali-Activated Cements: A Review

by Lourdes Soriano, Mauro M. Tashima, Lucía Reig, Jordi Payá, María V. Borrachero, José M. Monzó and Ángel M. Pitarch

Buildings 2023, 13(12), 3022; https://doi.org/10.3390/buildings13123022 - 04 Dec 2023

Viewed by 825

Abstract

Concrete and ceramic products are among the most widely used materials in the construction sector. The production of ceramic materials has significantly grown in recent years. Concrete is one of the most widely used materials worldwide and most of its carbon dioxide (CO [...] Read more.

Concrete and ceramic products are among the most widely used materials in the construction sector. The production of ceramic materials has significantly grown in recent years. Concrete is one of the most widely used materials worldwide and most of its carbon dioxide (CO₂) emissions are attributed to Portland cement (PC) production. This review analyzed previous research works into the use of ceramic waste (CW) as a precursor in alkali-activated (AA) cements. The physico-chemical properties of different CW materials were analyzed, and the properties and environmental impact of three main categories of AA CW cements were explored: those developed solely with CW; hybrid cements combining CW with traditional binders (PC, calcium hydroxide or calcium aluminate cement); combinations of CW with other precursors (i.e., blast furnace slag, fly ash, fluid catalytic cracking residue, etc.). The results evidenced that CW can be successfully employed as a precursor in AA cements, particularly in the context of prefabricated products where thermal curing is a prevalent procedure. When enhanced mechanical strength is requisite, it is feasible to attain improvements by employing hybrid systems or by combining CW with other precursors, such as blast furnace slag. This new alternative reuse option allows progress to be made toward sustainable development by reducing not only CO₂ emissions and embodied energy compared to PC but also PC consumption and CW accumulation in landfills. Full article

(This article belongs to the Special Issue Recent Scientific Developments in Cement-Based and Alternative Materials)

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26 pages, 5463 KiB

Open AccessReview

Comprehensive Review of Direct and Indirect Pozzolanic Reactivity Testing Methods

by Farzaneh Elyasigorji, Farhad Farajiani, Milad Hajipour Manjili, Qian Lin, Sina Elyasigorji, Visar Farhangi and Habib Tabatabai

Buildings 2023, 13(11), 2789; https://doi.org/10.3390/buildings13112789 - 06 Nov 2023

Cited by 6 | Viewed by 1679

Abstract

The production of portland cement is among the major contributors to greenhouse gas emissions that adversely affect the environment. Identifying sustainable materials to partially replace portland cement in concrete, such as pozzolanic materials, is crucial in addressing this issue. These materials mainly consist [...] Read more.

The production of portland cement is among the major contributors to greenhouse gas emissions that adversely affect the environment. Identifying sustainable materials to partially replace portland cement in concrete, such as pozzolanic materials, is crucial in addressing this issue. These materials mainly consist of silica and alumina that react with the available calcium hydroxide to form strength-bearing phases such as calcium silicate hydrates. Understanding the degree of pozzolanic reactivity of materials using efficient reactivity test methods is an important consideration. The paper thoroughly reviews the available literature related to direct and indirect pozzolanic reactivity test methods that have been utilized over the years. Direct methods quantify the amount of consumed calcium hydroxide, whereas indirect methods assess changes in the physical properties of the specimen due to pozzolanic reactions. The aim of this paper is to identify affordable, time-saving, and effective direct and indirect methods. Based on this study, the Frattini, electrical conductivity, and pH tests are considered the most time-efficient methods to assess pozzolanic materials. Electrical conductivity and pH tests are also easy to perform. In contrast, other methods are more time-consuming. Full article

(This article belongs to the Special Issue Recent Scientific Developments in Cement-Based and Alternative Materials)

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