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Buildings
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Eco-Friendly Building Materials: Recycled Waste and Sustainable Design
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Eco-Friendly Building Materials: Recycled Waste and Sustainable Design

A special issue of Buildings (ISSN 2075-5309). This special issue belongs to the section "Building Materials, and Repair & Renovation".

Deadline for manuscript submissions: closed (10 December 2024) | Viewed by 12285

Special Issue Editors

Dr. Yanni Bouras

E-Mail Website
Guest Editor
Built Environment and Engineering, Institute of Sustainable Industries and Liveable Cities (ISILC), Victoria University, Melbourne, VIC 3011, Australia
Interests: concrete durability; steel structures; machine learning; structural stability; sustainable construction materials; circular economy in construction
Special Issues, Collections and Topics in MDPI journals
Dr. Le Li

E-Mail Website
Guest Editor
College of Sport, Health and Engineering, Institute of Sustainable Industries and Liveable Cities, Victoria University, Melbourne, VIC 3011, Australia
Interests: sustainability and built environment; construction materials; risk assessment and management; construction management
Special Issues, Collections and Topics in MDPI journals
Dr. Wasantha Liyanage

E-Mail Website
Guest Editor
College of Sport, Health and Engineering, Institute of Sustainable Industries and Liveable Cities, Victoria University, Melbourne, VIC 3011, Australia
Interests: geotechnical engineering; sustainable construction; reactive soils; rock mechanics; tunneling
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Conventional construction depends on the extraction of huge quantities of natural resources and the utilization of high-carbon-emitting materials, which adversely impact the natural environment. Another challenge facing the health of our planet is the production of vast volumes of waste which are discarded in landfill sites, several of which stem from the building and construction industry. Hence, it is critical that the building and construction sector adopts environmentally sustainable practices to mitigate these environmental impacts and the harmful effects of climate change.

Increasingly, waste streams are being viewed as a valuable resource that can be utilized for the development of novel and sustainable building materials. Additionally, there is a growing demand for low-carbon materials resulting in great innovations in concrete and steel technology. We are pleased to announce this Special Issue of Buildings, titled "Eco-Friendly Building Materials: Recycled Waste and Sustainable Design", which aims to further enrich the body of knowledge on environmentally sustainable building materials and highlight innovative approaches to material development. This Special Issue will focus on the performance and production of materials that incorporate recycled waste content and/or achieve substantial emission reductions.

Dr. Yanni Bouras
Dr. Le Li
Dr. Wasantha Liyanage
Guest Editors

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. Buildings is an international peer-reviewed open access semimonthly 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 2600 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

  • building materials
  • embodied energy
  • environmental impacts
  • recycled waste
  • sustainable construction

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Further information on MDPI's Special Issue polices can be found here.

Published Papers (8 papers)

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Research

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25 pages, 9570 KiB  
Article
The Effect of Recycled Crushed Brick Aggregate on the Physical–Mechanical Properties of Earth Blocks
by Carlos Alberto Casapino-Espinoza, José Manuel Gómez-Soberón and María Consolación Gómez-Soberón
Buildings 2025, 15(1), 145; https://doi.org/10.3390/buildings15010145 - 6 Jan 2025
Viewed by 439
Abstract
The use of different components, such as alternative aggregates, represents an innovation in construction. According to various studies, these components improve certain properties of the elements that incorporate them. Specifically, recycled construction aggregates (RCAs)—such as crushed ceramic bricks (CCBs)—offer several benefits, including reducing [...] Read more.
The use of different components, such as alternative aggregates, represents an innovation in construction. According to various studies, these components improve certain properties of the elements that incorporate them. Specifically, recycled construction aggregates (RCAs)—such as crushed ceramic bricks (CCBs)—offer several benefits, including reducing landfill waste, enhancing the mechanical properties of the elements that integrate them, and ensuring availability. This research focuses on utilizing these waste materials and determining their feasibility and compatibility (in the short term) for manufacturing traditional earth blocks (EBs). This is achieved by studying the physical and mechanical properties of CCBs in matrices for EB construction, adhering to performance standards, emphasizing the advantages these aggregates provide for mechanical properties in sustainable construction and applying them in the context of traditional construction. Correlations were established through a statistical study of experimental data, graphically indicating the relationship between the different properties of CCBs, the mix design process, and the structural behavior of the resulting EB. Based on the key variable of the CCB replacement percentage, properties such as the elastic module by ultrasound, porosity, and expansion by hygroscopicity were analyzed, alongside mechanical properties like compressive and flexural strength. The results show that EBs with CCBs increases porosity by up to 21.59%. These blocks exhibit dimensional shrinkage of up to 14.5%, correlating with the increase in the CCB content. This aggregate replacement leads to a reduction in compressive strength (up to −23%) and flexural strength (up to −17.43%); however, all CCB content levels studied met the requirements of the applied standards. It is concluded that CCBs satisfactorily modifies the properties of the EBs and is suitable for use in construction. Full article
(This article belongs to the Special Issue Eco-Friendly Building Materials: Recycled Waste and Sustainable Design)
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Graphical abstract

Graphical abstract
Full article ">Figure 1
<p>Aggregates used to produce EBs: (<b>a</b>) E, (<b>b</b>) CCBs.</p> Full article ">Figure 2
<p>Granulometry of the E and CCBs used, and of the different dosages studied.</p> Full article ">Figure 3
<p>Comparison of the LL and PL of the E and the CCBs under study.</p> Full article ">Figure 4
<p>(<b>a</b>) Concrete mixer and mixing materials; (<b>b</b>) First saturation and hydration rest; (<b>c</b>) Humidity control and correction; (<b>d</b>) Block making in molds; (<b>e</b>) Drying and curing; (<b>f</b>) Face polishing.</p> Full article ">Figure 5
<p>UPV equipment positioned in one of the samples.</p> Full article ">Figure 6
<p>TGA equipment.</p> Full article ">Figure 7
<p>HC content for CCBs replacing E.</p> Full article ">Figure 8
<p>Apparent solid density, bulk density, and pore content.</p> Full article ">Figure 9
<p>Δ<sub>x</sub> of the study matrices from HC ≈ 0. Regression equations valid only for phase 3.</p> Full article ">Figure 10
<p>RH ratio for the study matrices. The dashed line shows the mean confidence interval (CI) for 95%.</p> Full article ">Figure 11
<p>Ratio of f<sub>b</sub> to study matrices, CI = 95%.</p> Full article ">Figure 12
<p>E∂ obtained for the different study matrices.</p> Full article ">Figure 13
<p>TG and dTGA tests for 100E and the different matrices incorporating replacement CCBs.</p> Full article ">Figure 14
<p>Example of obtaining samples for OIA study. (<b>a</b>) Sample cutting, (<b>b</b>) epoxy resin embedding, (<b>c</b>) metallographic polishing, (<b>d</b>) surface of the face to be studied, and (<b>e</b>) definition of area of interest.</p> Full article ">Figure 15
<p>Identification of the four phases of components present in the microstructure of each area of interest in the different matrices that compose the research. (<b>a</b>) Matrix 100E, (<b>b</b>) Matrix 95E + 5CCB, (<b>c</b>) Matrix 90E + 10CCB, and (<b>d</b>) Matrix 80E + 20CCB.</p> Full article ">Figure 16
<p>Percentage areas of the different phases identified in the OIA process.</p> Full article ">
12 pages, 3633 KiB  
Article
Estimation of Chemical and Mineral Composition, Structural Features, and Pre-Firing Technological Properties of Waste Coal Heaps for Ceramic Production
by Khungianos Yavruyan and Vladimir Kotlyar
Buildings 2024, 14(7), 1905; https://doi.org/10.3390/buildings14071905 - 22 Jun 2024
Cited by 1 | Viewed by 1099
Abstract
The relevance of the investigation and creation of a new non-traditional raw material base for wall ceramics for the south of Russia is shown in connection with the decreasing availability of traditional raw materials—loams. Characterizations of the mineral and chemical constituent rock formations [...] Read more.
The relevance of the investigation and creation of a new non-traditional raw material base for wall ceramics for the south of Russia is shown in connection with the decreasing availability of traditional raw materials—loams. Characterizations of the mineral and chemical constituent rock formations of the rocks composing the dumps of coal waste heaps and enrichment plants are given. A serious constraint for the industrial development of coal wastes is the requirement for a great variety of mineral constituents. The chemical and mineralogical compositions and the pre-firing ceramic properties of the waste coal heaps are studied and presented in detail. It is mentioned that fine and thin materials contain coal in an increased amount; due to this, they cannot be considered as the main raw material for the production of wall ceramics. The materials of the medium-sized grain group (2.0–5.0 mm, sifting) can contain up to 2–3% of coal and are most often represented by a mixture of mudstones, siltstones, and sandstones, with the predominance of one or another type of rock. The granulometric composition and the content of large-grained inclusions, molding moisture, plasticity, cohesiveness, desiccation properties, and air shrinkage were studied and determined. It is concluded that the middle group of waste coal heaps in particular are of the greatest interest as a basic raw material for the production of wall ceramic products. Full article
(This article belongs to the Special Issue Eco-Friendly Building Materials: Recycled Waste and Sustainable Design)
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Figure 1
<p>Radiograph WCH of the Eastern Donbass.</p> Full article ">Figure 2
<p>Intergrowths of coal particles with host rocks of fraction 0.63–1.25 (<b>a</b>) and particles of pure coal of fraction 0.315–0.63 mm (<b>b</b>).</p> Full article ">Figure 3
<p>Thermogram of WCH with coal content of about 40%.</p> Full article ">Figure 4
<p>Photos of WCH grain chips under an electron microscope.</p> Full article ">Figure 5
<p>Microphotograph and spectrum of hydrous mica grains.</p> Full article ">
18 pages, 6875 KiB  
Article
Assessment of Elaboration and Performance of Rice Husk-Based Thermal Insulation Material for Building Applications
by Karin Rodríguez Neira, Juan Pablo Cárdenas-Ramírez, Carlos Javier Rojas-Herrera, Laia Haurie, Ana María Lacasta, Joaquín Torres Ramo and Ana Sánchez-Ostiz
Buildings 2024, 14(6), 1720; https://doi.org/10.3390/buildings14061720 - 8 Jun 2024
Cited by 1 | Viewed by 3287
Abstract
Developing environmentally friendly building materials with low environmental impacts is receiving more attention nowadays to face the global challenges of climate change; building insulation materials made from agricultural waste can be used for their low environmental impact and to generate responsible supplies that [...] Read more.
Developing environmentally friendly building materials with low environmental impacts is receiving more attention nowadays to face the global challenges of climate change; building insulation materials made from agricultural waste can be used for their low environmental impact and to generate responsible supplies that utilize natural resources adequately. The study aims to assess a panel made from rice husk using the pulping method. An experimental design established the proportion of rice husk, the percentage of additive (NaOH concentration), boiling time and blending time. Taguchi’s method was applied to investigate the effect on density and thermal conductivity; the final panel with optimum conditions was morphologically analyzed using scanning electron microscopy (SEM); the thermal behavior was studied by thermogravimetric analysis (TGA); fire reaction and smoldering behavior were analyzed; and characterization in water absorption and acoustic absorption performances were established. The results show thermal conductivity values between 0.037 and 0.042 W/mK, a smoldering velocity of 3.40 mm/min, and a good acoustic absorption coefficient in octave frequency bands between 125 Hz and 4 kHz greater than 0.7. These characteristics are competitive with other insulating bio-based materials available on the market. This study employed chemicals utilized by other biomaterials for the pulping process and in flame retardants. However, it is important to investigate natural treatments or those with a diminished environmental impact. Full article
(This article belongs to the Special Issue Eco-Friendly Building Materials: Recycled Waste and Sustainable Design)
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Figure 1
<p>Steps in manufacturing the samples.</p> Full article ">Figure 2
<p>Thermal conductivity measurement equipment.</p> Full article ">Figure 3
<p>Process of measurement of moisture.</p> Full article ">Figure 4
<p>Epiradiator test.</p> Full article ">Figure 5
<p>Smoldering setup.</p> Full article ">Figure 6
<p>Point of measurement in the acoustic samples and in situ setup of the probe.</p> Full article ">Figure 7
<p>SEM analysis: (<b>a</b>) internal longitudinal; (<b>b</b>) external longitudinal; (<b>c</b>) cross-section of natural rice husk; (<b>d</b>) internal longitudinal; (<b>e</b>) external longitudinal; (<b>f</b>) cross-section of processed rice husk.</p> Full article ">Figure 8
<p>Energy dispersive X-ray spectroscopy (EDS): (<b>a</b>) natural rice husk; (<b>b</b>) processed rice husk.</p> Full article ">Figure 9
<p>Thermal stability of rice husk (TGA).</p> Full article ">Figure 10
<p>(<b>a</b>) Percentage of water absorption in samples of the rice husk, wood fiber and glass wool; (<b>b</b>) the samples after 24 h of immersion.</p> Full article ">Figure 11
<p>Samples after epiradiator test.</p> Full article ">Figure 12
<p>Smoldering process thermography.</p> Full article ">Figure 13
<p>Temperature evolution for thermocouples located every 3 cm along. Pre-set temperature of the hot plate: 360 °C. (<b>a</b>) RH untreated; (<b>b</b>) wood fiber; (<b>c</b>) RH + 10% Solubor; (<b>d</b>) RH + 10% H<sub>3</sub>BO<sub>3</sub> + Borax.</p> Full article ">Figure 14
<p>Smoldering propagation velocities are calculated as the slope of the obtained linear regression.</p> Full article ">Figure 15
<p>Comparison between the sound absorption coefficients obtained for the two samples. In each case, the average of 8 measurements and their standard deviation, evaluated in octave bands, is shown.</p> Full article ">
21 pages, 4923 KiB  
Article
A Novel Eco-Friendly Thermal-Insulating High-Performance Geopolymer Concrete Containing Calcium Oxide-Activated Materials from Waste Tires and Waste Polyethylene Terephthalate
by Shen-Lun Tsai, Her-Yung Wang, Keng-Ta Lin and Chang-Chi Hung
Buildings 2024, 14(5), 1437; https://doi.org/10.3390/buildings14051437 - 16 May 2024
Cited by 1 | Viewed by 1144
Abstract
This study presents an innovative approach for the utilization of industrial by-products and municipal waste in the production of sustainable and environmentally friendly cement mortar. We explored stabilized stainless-steel reduced slag (SSRS) and polyethylene (PE) plastic waste as partial replacements for aggregates. Various [...] Read more.
This study presents an innovative approach for the utilization of industrial by-products and municipal waste in the production of sustainable and environmentally friendly cement mortar. We explored stabilized stainless-steel reduced slag (SSRS) and polyethylene (PE) plastic waste as partial replacements for aggregates. Various engineering properties of the resulting cement mortar specimens, including the slump, slump flow, compressive strength, flexural strength, tensile strength, water absorption, and ultrasonic pulse velocity (UPV), were investigated through comprehensive experimental tests. The influence of different water–cement (w/c) or water–binder (w/b) ratios and substitution amounts on the engineering properties of the cement mortar samples was thoroughly examined. The findings revealed that an increase in PE substitution adversely affected the overall workability of the cement mortar mixtures, whereas an increase in the SSRS amount contributed to enhanced workability. As for the hardened properties, a consistent trend was observed in both cases, with higher w/c or w/b ratios and substitution amounts leading to reduced mechanical properties. Water absorption and UPV test results validated the increased formation of porosity with higher w/c or w/b ratios and substitution amounts. This study proposes a promising method to effectively repurpose industrial by-products and municipal waste, transforming them into sustainable construction and building materials. Additionally, a comparative analysis of the transportation costs and carbon footprint emissions between SSRS–cement mortar and PE–cement mortar was conducted to assess their environmental impact and sustainability. Generally, higher w/c or w/b ratios and replacement levels corresponded with a reduced carbon footprint. The geographical location of the source of SSRS and PE remains a challenge and studies to overcome this challenge must be further explored. Full article
(This article belongs to the Special Issue Eco-Friendly Building Materials: Recycled Waste and Sustainable Design)
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Figure 1

Figure 1
<p>SSRS obtained as the by-product of producing stainless steel.</p> Full article ">Figure 2
<p>Recycled PE obtained from single-use plastic food-container wastes.</p> Full article ">Figure 3
<p>Slump measurement of cement mortar samples with different (<b>a</b>) PE substitution amounts and (<b>b</b>) SRSS substitution amounts.</p> Full article ">Figure 4
<p>Flow of cement mortar samples with different (<b>a</b>) PE substitution amounts and (<b>b</b>) SRSS substitution amounts.</p> Full article ">Figure 5
<p>Compressive strength of cement mortar samples with different w/c and PE substitution amounts.</p> Full article ">Figure 6
<p>Compressive strength of cement mortar samples with different w/b and SSRS substitution amounts.</p> Full article ">Figure 7
<p>Flexural strength of cement mortar samples with different w/c ratios and PE substitution amounts.</p> Full article ">Figure 8
<p>Flexural strength of cement mortar samples with different w/b ratios and SSRS substitution amounts.</p> Full article ">Figure 9
<p>Tensile strength of cement mortar samples with different w/c ratios and PE substitution amounts.</p> Full article ">Figure 10
<p>Tensile strength of cement mortar samples with different w/b ratios and SSRS substitution amounts.</p> Full article ">Figure 11
<p>UPV of cement mortar samples with different w/c ratios and PE substitution amounts.</p> Full article ">Figure 12
<p>UPV of cement mortar samples with different w/b ratios and SSRS substitution amounts.</p> Full article ">Figure 13
<p>Water absorption of cement mortar samples with different w/c ratios and PE substitution amounts.</p> Full article ">Figure 14
<p>Water absorption of cement mortar samples with different w/b ratios and SSRS substitution amounts.</p> Full article ">
24 pages, 11999 KiB  
Article
Evaluation of Eco-Friendly Consolidating Treatments in Pugliese Tuff (Gravina Calcarenite) Used in Italian Heritage Buildings
by Jose Antonio Huesca-Tortosa, Yolanda Spairani-Berrio, Cristiano Giuseppe Coviello, Maria Francesca Sabbà, Fabio Rizzo and Dora Foti
Buildings 2024, 14(4), 940; https://doi.org/10.3390/buildings14040940 - 29 Mar 2024
Cited by 4 | Viewed by 1176
Abstract
This work evaluates the effectiveness of various consolidating treatments applied to Pugliese tuff (Gravina Calcarenite). This type of stone has been used in numerous historic buildings in the Puglia area (southeast of Italy), which presents durability problems due to high porosity, low cohesion [...] Read more.
This work evaluates the effectiveness of various consolidating treatments applied to Pugliese tuff (Gravina Calcarenite). This type of stone has been used in numerous historic buildings in the Puglia area (southeast of Italy), which presents durability problems due to high porosity, low cohesion between clasts, and low mechanical resistance. Eco-friendly treatments that generate CaCO3 have been selected, specifically bioconsolidant KBYO biological and lime water, which a priori are capable of consolidating without occluding the pores or reducing them excessively, thereby creating compounds similar to those contained in the stone and being respectful of the environment. Nano-sized treatments have also been tested, including nanosilica and nanolime, to compare results with eco-friendly treatments. The bioconsolidating treatment has been applied in two different ways, the usual way consisting of two applications a day for 7 days, as well as a double treatment that is applied in two batches of 7 days with a rest of 7 days between applications. Double treatment has shown a great improvement in consolidation compared to the usual 7-day application; this treatment has obtained the best results in both mechanical and petrophysical properties. This study not only demonstrates the effectiveness of the bioconsolidant but also expands eco-friendly conservation strategies to improve the preservation of historical structures built in calcarenite. Full article
(This article belongs to the Special Issue Eco-Friendly Building Materials: Recycled Waste and Sustainable Design)
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Figure 1

Figure 1
<p>Building in Bari (Italy) realized with Gravina Calcarenite stone. It is appreciated features induced by material loss like alveolizations.</p> Full article ">Figure 2
<p>Workflow.</p> Full article ">Figure 3
<p>Thin-section micrographs of Gravina Calcarenite used in these studies. Marine fossils are marked with white arrows. It has been observed through a polarizing petrographic microscope.</p> Full article ">Figure 4
<p>(<b>a</b>) Color study with colorimeter. (<b>b</b>) Glass containers with the specimens after water vapor permeability test. (<b>c</b>) Droplet absorption test.</p> Full article ">Figure 5
<p>(<b>a</b>) Ultrasonic test. (<b>b</b>) Compression test. (<b>c</b>) DRMS testing process.</p> Full article ">Figure 6
<p>Colorimetric data of color difference between the same specimen (disk nº 3) untreated (standard) and treated with bioconsolidant for 7 days (sample). It can be seen that the total difference is ΔE* = 7.168, a value higher than 3, the limit at which it is invisible to the naked eye.</p> Full article ">Figure 7
<p>Handheld microscope view of the same specimen of Gravina Calcarenite, untreated and bioconsolidated with double application of the treatment. The orange areas correspond to the ankerite. The common zones are indicated in the images with the arrows.</p> Full article ">Figure 8
<p>SEM observation of the same untreated and treated specimen. Colored frames indicate enlarged areas. The (<b>top</b>) row shows the untreated specimen, and the (<b>bottom</b>) row shows the bioconsolidated specimen with 7 days of treatment. The biofilm is visible in the last picture on the right.</p> Full article ">Figure 9
<p>(<b>a</b>) SEM view of the specimen treated with double application of bioconsolidant showing at 1000× magnification the entire surface enveloped by biofilm. (<b>b</b>) FE-SEM observation of Gravina Calcarenite with double bioconsolidant treatment. At 5000 magnification, the calcified bacteria can be distinguished with rounded shapes that surround and consolidate the original stone matrix.</p> Full article ">Figure 10
<p>Capillary absorption graph at the same specimens (before and after being treated): (<b>a</b>) untreated specimens (before applying the bioconsolidant); (<b>b</b>) treated specimens with bioconsolidant; (<b>c</b>) untreated specimens (before applying the double bioconsolidant); (<b>d</b>) treated specimens with double bioconsolidant. Less capillary absorption is seen in the double-treated specimens.</p> Full article ">Figure 11
<p>Photographs of the capillary absorption test of specimen 5. (<b>a</b>) Untreated at 11 s. (<b>b</b>) Untreated at 59 s. (<b>c</b>) Bioconsolidated with double treatment at 31 s. (<b>d</b>) Bioconsolidated with double treatment after 5 min.</p> Full article ">Figure 12
<p>SEM observation of the same specimen untreated and treated with lime water. Colored frames indicate enlarged areas. The (<b>top</b>) row shows the untreated specimen and the (<b>bottom</b>) row the treated specimen. The arrows indicate the consolidated areas.</p> Full article ">Figure 13
<p>Capillary absorption graph of the average of the same specimens: (<b>a</b>) untreated; (<b>b</b>) treated with lime water.</p> Full article ">Figure 14
<p>SEM observation of the same specimen untreated and treated with nanolimes. In the (<b>upper</b>) row is the untreated specimen and in the (<b>lower</b>) row the treated specimen. Colored frames indicate enlarged areas. The arrow indicates the consolidated areas.</p> Full article ">Figure 15
<p>Capillary absorption graph of the same specimens: (<b>a</b>) untreated; (<b>b</b>) treated with nanolimes.</p> Full article ">Figure 16
<p>SEM observation of the same specimen untreated and treated with nanosilica (Nano Estel). In the (<b>upper</b>) row is the untreated specimen and in the (<b>lower</b>) row the treated specimen. Colored frames indicate enlarged areas. The arrows point to the same areas before and after being treated.</p> Full article ">Figure 17
<p>Capillary absorption graph of the same specimens: (<b>a</b>) untreated; (<b>b</b>) treated with nanolimes.</p> Full article ">Figure 18
<p>DRMS resistance graph. In the vertical axis, the resistance in N and in the horizontal axis, the depth of the test up to 200 mm.</p> Full article ">Figure 19
<p>Pore size distribution graph. (<b>a</b>) Untreated. (<b>b</b>) Lime water. (<b>c</b>) Double bioconsolidation. (<b>d</b>) Bioconsolidation. (<b>e</b>) Nanolimes. (<b>f</b>) Nanosilica.</p> Full article ">
24 pages, 7046 KiB  
Article
Utilisation of Machine Learning Techniques to Model Creep Behaviour of Low-Carbon Concretes
by Yanni Bouras and Le Li
Buildings 2023, 13(9), 2252; https://doi.org/10.3390/buildings13092252 - 5 Sep 2023
Cited by 2 | Viewed by 1363
Abstract
Low-carbon concrete mixes that incorporate high volumes of fly ash and slag as cement replacements are becoming increasingly more common as part of efforts to decarbonise the construction industry. Though environmental benefits are offered, concretes containing supplementary cementitious materials exhibit different creep behaviour [...] Read more.
Low-carbon concrete mixes that incorporate high volumes of fly ash and slag as cement replacements are becoming increasingly more common as part of efforts to decarbonise the construction industry. Though environmental benefits are offered, concretes containing supplementary cementitious materials exhibit different creep behaviour when compared to conventional concrete. Creep can significantly impact long-term structural behaviour and influence the overall serviceability and durability of concrete structures. This paper develops a creep compliance prediction model using supervised machine learning techniques for concretes containing fly ash and slag as cement substitutes. Gaussian process regression (GPR), artificial neural networks (ANN), random forest regression (RFR) and decision tree regression (DTR) models were all considered. The dataset for model training was developed by mining relevant data from the Infrastructure Technology Institute of Northwestern University’s comprehensive creep dataset in addition to extracting data from the literature. Holdout validation was adopted with the data partitioned into training (70%) and validation (30%) sets. Based on statistical indicators, all machine learning models can accurately model creep compliance with the RFR and GPR found to be the best-performing models. The sensitivity of the GPR model’s performance to training repetitions, input variable selection and validation methodology was assessed, with the results indicating small variability. The importance of the selected input variables was analysed using the Shapley additive explanation. It was found that time was the most significant parameter, with loading age, compressive strength, elastic modulus, volume-to-surface ratio and relative humidity also showing high importance. Fly ash and silica fume content featured the least influence on creep prediction. Furthermore, the predictions of the trained models were compared to experimental data, which showed that the GPR, RFR and ANN models can accurately reflect creep behaviour and that the DTR model does not give accurate predictions. Full article
(This article belongs to the Special Issue Eco-Friendly Building Materials: Recycled Waste and Sustainable Design)
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Figure 1

Figure 1
<p>Histograms of input data relating to testing parameters: (<b>a</b>) time, (<b>b</b>) loading age, (<b>c</b>) volume-to-surface ratio and (<b>d</b>) relative humidity.</p> Full article ">Figure 2
<p>Histograms of input variables relating to concrete properties: (<b>a</b>) 28-day compressive strength, (<b>b</b>) 28-day elastic modulus, (<b>c</b>) slag-to-binder ratio, (<b>d</b>) fly ash-to-binder ratio, (<b>e</b>) water-to-binder ratio and (<b>f</b>) aggregate-to-binder ratio.</p> Full article ">Figure 3
<p>Framework of supervised learning.</p> Full article ">Figure 4
<p>Architecture of artificial neural network [<a href="#B32-buildings-13-02252" class="html-bibr">32</a>].</p> Full article ">Figure 5
<p>Structure of DTR: General Structure (<b>a</b>) and structure developed herein for creep prediction (<b>b</b>).</p> Full article ">Figure 6
<p>Structure of random forest prediction: General Structure (<b>a</b>) and structure developed herein for creep prediction (<b>b</b>).</p> Full article ">Figure 7
<p>ANN model establishment in MATLAB.</p> Full article ">Figure 8
<p>Predicted versus true responses for ANN model with training data (<b>a</b>) and testing data (<b>b</b>), DTR model with training data (<b>c</b>) and testing data (<b>d</b>), and for RFR model with training data (<b>e</b>) and testing data (<b>f</b>).</p> Full article ">Figure 9
<p>Predicted response versus true response for Matern 5/2-GPR model (validation data).</p> Full article ">Figure 10
<p>Effect on training data size on prediction accuracy for all ML models with random individual data point selection (<b>a</b>) and for the RQ-GPR model with random creep curve selection (<b>b</b>).</p> Full article ">Figure 11
<p>Shapley value absolute averages (<b>a</b>) and a Box and Whisker plot (<b>b</b>) showing Shapley value distribution for slag concretes.</p> Full article ">Figure 12
<p>Shapley value absolute averages (<b>a</b>) and a Box and Whisker plot (<b>b</b>) showing Shapley value distribution for fly ash concrete.</p> Full article ">Figure 13
<p>Shapley values versus input parameters: time since loading (<b>a</b>), age at loading (<b>b</b>), volume-to-surface ratio (<b>c</b>), relative humidity (<b>d</b>), 28-day compressive strength (<b>e</b>) and 28-day elastic modulus (<b>f</b>).</p> Full article ">Figure 14
<p>Shapley values versus input parameters: fly ash content (<b>a</b>), slag content (<b>b</b>), silica fume content (<b>c</b>), cement content (<b>d</b>), water content (<b>e</b>) and total aggregate content (<b>f</b>).</p> Full article ">Figure 15
<p>Predictions of GPR and RFR (<b>a</b>) and ANN and DTR (<b>b</b>) model compared to experimental data for fly ash concrete including varied loading age.</p> Full article ">Figure 16
<p>Predictions of GPR and RFR (<b>a</b>) and ANN and DTR (<b>b</b>) model compared to experimental data for slag concrete including varied slag mass.</p> Full article ">
17 pages, 5482 KiB  
Article
A Preliminary Study Was Conducted on the Compressive Strength and Flow Performance of Environmentally Friendly UHPC-SCA
by Shuwei Wang, Min Zhang, Yaoyang Shi, Lixin Chen and Yingming Zhou
Buildings 2023, 13(9), 2226; https://doi.org/10.3390/buildings13092226 - 31 Aug 2023
Cited by 1 | Viewed by 1056
Abstract
This research paper explores using marine shells as coarse aggregates in producing seawater sea sand UHPC-CA. The study examined factors such as coarse aggregates (granite, oyster shell, and cone shell), fine aggregates (sea sand and river sand), fiber types, and content. The research [...] Read more.
This research paper explores using marine shells as coarse aggregates in producing seawater sea sand UHPC-CA. The study examined factors such as coarse aggregates (granite, oyster shell, and cone shell), fine aggregates (sea sand and river sand), fiber types, and content. The research findings indicate that different coarse aggregates and fibers influence the flow performance of UHPC-SCA. The study identified the cone shell as the best coarse shell aggregate and 1.5% steel fiber as the optimal fiber and inclusion amount. The compressive strength of this combination reached 106 MPa, which is comparable to the granite stone UHPC-CA of the same particle size. Full article
(This article belongs to the Special Issue Eco-Friendly Building Materials: Recycled Waste and Sustainable Design)
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<p>Waste shells.</p> Full article ">Figure 2
<p>Detailed information on various test materials.</p> Full article ">Figure 3
<p>Marine UHPC-SCA test flow.</p> Full article ">Figure 4
<p>Effect of different fibers and aggregates on the fluidity of UHPC-CA. (<b>a</b>) SF, (<b>b</b>) PVA, (<b>c</b>) PP, (<b>d</b>) oyster shell, (<b>e</b>) cone shell.</p> Full article ">Figure 5
<p>Comparison of slump and spread of UHPC-CA in each group. (<b>a</b>) Different coarse aggregates, (<b>b</b>) Fiber content of granite, (<b>c</b>) The fiber content in the cone shells, (<b>d</b>) The fiber content in the Oyster shells.</p> Full article ">Figure 6
<p>Compressive strength of granite UHPC-CA. (<b>a</b>) Granite macadam, (<b>b</b>) SF content, (<b>c</b>) 1.5% SF content, (<b>d</b>) 2% SF content.</p> Full article ">Figure 7
<p>Compressive strength of oyster shells UHPC-SCA. (<b>a</b>) Oyster shell, (<b>b</b>) Fiber content.</p> Full article ">Figure 8
<p>Compressive strength of cone shells UHPC-SCA. (<b>a</b>) Cone snail, (<b>b</b>) Optimal coarse aggregate.</p> Full article ">Figure 9
<p>Relationship between fluidity and compressive strength of UHPC-CA in marine shells, seawater, and sea sand. (<b>a</b>) The fiber content in oyster shells, (<b>b</b>) The fiber content in the cone shells. Note: The diagram indicates the flow performance by the dotted line. The histogram shows the compressive strength, with orange representing 3 days, green representing 7 days, and purple representing 28 days.</p> Full article ">Figure 10
<p>Macroscopic images of various UHPC-CA test blocks. (<b>a</b>) Granite macadam, (<b>b</b>) oyster shells, (<b>c</b>) cone shells.</p> Full article ">

Review

Jump to: Research

20 pages, 6934 KiB  
Review
Feasibility of Repairing Concrete with Ultra-High Molecular Weight Polyethylene Fiber Cloth: A Comprehensive Literature Review
by Zengrui Pan, Rabin Tuladhar, Shi Yin, Feng Shi and Faning Dang
Buildings 2024, 14(6), 1631; https://doi.org/10.3390/buildings14061631 - 2 Jun 2024
Cited by 2 | Viewed by 1238
Abstract
This review explores the use of Ultra-High Molecular Weight Polyethylene (UHMWPE) fiber cloth as an innovative solution for the repair and reinforcement of concrete structures. UHMWPE is a polymer formed from a very large number of repeated ethylene (C2H4) [...] Read more.
This review explores the use of Ultra-High Molecular Weight Polyethylene (UHMWPE) fiber cloth as an innovative solution for the repair and reinforcement of concrete structures. UHMWPE is a polymer formed from a very large number of repeated ethylene (C2H4) units with higher molecular weight and long-chain crystallization than normal high-density polyethylene. With its superior tensile strength, elongation, and energy absorption capabilities, UHMWPE emerges as a promising alternative to traditional reinforcement materials like glass and carbon fibers. The paper reviews existing literature on fiber-reinforced polymer (FRP) applications in concrete repair in general, highlighting the unique benefits and potential of UHMWPE fiber cloth compared to other commonly used methods of strengthening concrete structures, such as enlarging concrete sections, near-surface embedded reinforcement, and externally bonded steel plate or other FRPs. Despite the scarcity of experimental data on UHMWPE for concrete repair, this review underscores its feasibility and calls for further research to fully harness its capabilities in civil engineering applications. Full article
(This article belongs to the Special Issue Eco-Friendly Building Materials: Recycled Waste and Sustainable Design)
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<p>Micro-structure of fiber, (<b>a</b>) normal polyethylene with low molecular orientation, (<b>b</b>) Ultra-High Molecular Weight Polyethylene Fiber [<a href="#B73-buildings-14-01631" class="html-bibr">73</a>].</p> Full article ">Figure 2
<p>Schematic of the chemical structures of ethylene and polyethylene [<a href="#B62-buildings-14-01631" class="html-bibr">62</a>].</p> Full article ">Figure 3
<p>Chemical and molecular interaction of crosslinking UHMWPE under high energy radiation [<a href="#B94-buildings-14-01631" class="html-bibr">94</a>].</p> Full article ">Figure 4
<p>High-resolution scanning electron micrograph with (<b>a</b>) global view of carbon nanotubes on UHMWPE and (<b>b</b>) detailed view of fibers pulled from CNT clusters [<a href="#B103-buildings-14-01631" class="html-bibr">103</a>].</p> Full article ">Figure 5
<p>Surface morphology of UHMWPE after different argon plasma treatment times of (<b>a</b>) 0 h, (<b>b</b>) 1 h, (<b>c</b>) 3 h, (<b>d</b>) 5 h [<a href="#B108-buildings-14-01631" class="html-bibr">108</a>].</p> Full article ">Figure 6
<p>Schematic diagram of (<b>a</b>) polystyrene on UHMWPE powder [<a href="#B116-buildings-14-01631" class="html-bibr">116</a>] and (<b>b</b>) schematic diagram of FRPs [<a href="#B110-buildings-14-01631" class="html-bibr">110</a>].</p> Full article ">Figure 7
<p>Small-size concrete specimen (40 mm × 40 mm × 160 mm) for flexural test: (<b>a</b>) initial photo of experimental specimen, (<b>b</b>) its crack pattern, and (<b>c</b>) failure mode [<a href="#B150-buildings-14-01631" class="html-bibr">150</a>].</p> Full article ">Figure 8
<p>Load-shortening curves for wrapped specimens with different layers of CFRP [<a href="#B156-buildings-14-01631" class="html-bibr">156</a>].</p> Full article ">Figure 9
<p>Load-displacement curves obtained in the structural tests: (<b>a</b>,<b>b</b>) represent different mixing proportions of cementitious composites, reinforced with UHMWPE/PVA and steel fiber [<a href="#B169-buildings-14-01631" class="html-bibr">169</a>].</p> Full article ">Figure 10
<p>Failure mode of epoxy–concrete bond: (<b>a</b>) in dry ambient conditions; (<b>b</b>) following exposure to moisture [<a href="#B196-buildings-14-01631" class="html-bibr">196</a>].</p> Full article ">
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