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Search Results (594)

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Keywords = volume of water absorption

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25 pages, 3035 KiB  
Article
Physical, Mechanical, and Durability Behavior of Sustainable Mortars with Construction and Demolition Waste as Supplementary Cementitious Material
by Sandra Cunha, Kubilay Kaptan, Erwan Hardy and José Aguiar
Buildings 2025, 15(15), 2757; https://doi.org/10.3390/buildings15152757 - 5 Aug 2025
Abstract
The construction industry plays a major role in the consumption of natural resources and the generation of waste. Construction and demolition waste (CDW) is produced in substantial volumes globally and is widely available. Its accumulation poses serious challenges related to storage and disposal, [...] Read more.
The construction industry plays a major role in the consumption of natural resources and the generation of waste. Construction and demolition waste (CDW) is produced in substantial volumes globally and is widely available. Its accumulation poses serious challenges related to storage and disposal, highlighting the need for effective strategies to mitigate the associated environmental impacts of the sector. This investigation intends to evaluate the influence of mixed CDW on the physical, mechanical, and durability properties of mortars with CDW partially replacing Portland cement, and allow performance comparisons with mortars produced with fly ash, a commonly used supplementary binder in cement-based materials. Thus, three mortar formulations were developed (reference mortar, mortar with 25% CDW, and mortars with 25% fly ash) and several characterization tests were carried out on the CDW powder and the developed mortars. The work’s principal findings revealed that through mechanical grinding processes, it was possible to obtain a CDW powder suitable for cement replacement and with good indicators of pozzolanic activity. The physical properties of the mortars revealed a decrease of about 10% in water absorption by immersion, which resulted in improved performance regarding durability, especially with regard to the lower carbonation depth (−1.1 mm), and a decrease of 51% in the chloride diffusion coefficient, even compared to mortars incorporating fly ash. However, the mechanical performance of the mortars incorporating CDW was reduced (25% in terms of flexural strength and 58% in terms of compressive strength), but their practical applicability was never compromised and their mechanical performance proved to be superior to that of mortars incorporating fly ash. Full article
(This article belongs to the Special Issue Research on Sustainable Materials in Building and Construction)
20 pages, 3271 KiB  
Article
Calculation Model for the Degree of Hydration and Strength Prediction in Basalt Fiber-Reinforced Lightweight Aggregate Concrete
by Yanqun Sun, Haoxuan Jia, Jianxin Wang, Yanfei Ding, Yanfeng Guan, Dongyi Lei and Ying Li
Buildings 2025, 15(15), 2699; https://doi.org/10.3390/buildings15152699 - 31 Jul 2025
Viewed by 192
Abstract
The combined application of fibers and lightweight aggregates (LWAs) represents an effective approach to achieving high-strength, lightweight concrete. To enhance the predictability of the mechanical properties of fiber-reinforced lightweight aggregate concrete (LWAC), this study conducts an in-depth investigation into its hydration characteristics. In [...] Read more.
The combined application of fibers and lightweight aggregates (LWAs) represents an effective approach to achieving high-strength, lightweight concrete. To enhance the predictability of the mechanical properties of fiber-reinforced lightweight aggregate concrete (LWAC), this study conducts an in-depth investigation into its hydration characteristics. In this study, high-strength LWAC was developed by incorporating low water absorption LWAs, various volume fractions of basalt fiber (BF) (0.1%, 0.2%, and 0.3%), and a ternary cementitious system consisting of 70% cement, 20% fly ash, and 10% silica fume. The hydration-related properties were evaluated through isothermal calorimetry test and high-temperature calcination test. The results indicate that incorporating 0.1–0.3% fibers into the cementitious system delays the early hydration process, with a reduced peak heat release rate and a delayed peak heat release time compared to the control group. However, fitting the cumulative heat release over a 72-h period using the Knudsen equation suggests that BF has a minor impact on the final degree of hydration, with the difference in maximum heat release not exceeding 3%. Additionally, the calculation model for the final degree of hydration in the ternary binding system was also revised based on the maximum heat release at different water-to-binder ratios. The results for chemically bound water content show that compared with the pre-wetted LWA group, under identical net water content conditions, the non-pre-wetted LWA group exhibits a significant reduction at three days, with a decrease of 28.8%; while under identical total water content conditions it shows maximum reduction at ninety days with a decrease of 5%. This indicates that pre-wetted LWAs help maintain an effective water-to-binder ratio and facilitate continuous advancement in long-term hydration reactions. Based on these results, influence coefficients related to LWAs for both final degree of hydration and hydration rate were integrated into calculation models for degrees of hydration. Ultimately, this study verified reliability of strength prediction models based on degrees of hydration. Full article
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21 pages, 570 KiB  
Article
The Impact of Cereal-Based Plant Beverages on Wheat Bread Quality: A Study of Oat, Millet, and Spelt Beverages
by Anna Wirkijowska, Piotr Zarzycki, Dorota Teterycz and Danuta Leszczyńska
Appl. Sci. 2025, 15(15), 8428; https://doi.org/10.3390/app15158428 - 29 Jul 2025
Viewed by 240
Abstract
Cereal-based plant beverages have gained attention as functional ingredients in bakery formulations, offering both nutritional and technological benefits. Replacing water with these beverages may improve the nutritional value of bread by increasing its fiber and unsaturated fatty acid content, while also introducing functional [...] Read more.
Cereal-based plant beverages have gained attention as functional ingredients in bakery formulations, offering both nutritional and technological benefits. Replacing water with these beverages may improve the nutritional value of bread by increasing its fiber and unsaturated fatty acid content, while also introducing functional components that affect dough rheology and bread texture. This study examined the effects of substituting water with oat (BO), millet (BM), and spelt (BS) beverages in wheat bread formulations at 25%, 50%, 75%, and 100% levels. Thirteen bread variants were prepared: one control and four substitution levels for each of the three cereal-based beverages, using the straight dough method, with hydration adjusted according to farinograph results. Farinograph tests showed increased water absorption (up to 64.5% in BO100 vs. 56.9% in control) and improved dough stability (10.6 min in BS100). Specific bread volume increased, with BS75 reaching 3.52 cm3/g compared to 3.09 cm3/g in control. Moisture content remained stable during storage, and crumb hardness after 72 h was lowest in BO100 (9.5 N) and BS75 (11.5 N), indicating delayed staling. All bread variants received favorable sensory ratings, with average scores above 3.75 on a 5-point scale. The highest bread yield (149.8%) and lowest baking loss (10.9%) were noted for BS100. Although BO breads had slightly higher fat and energy content, their nutritional profile remained favorable due to unsaturated fatty acids. Overall, oat and spelt beverages demonstrated the greatest potential as functional water substitutes, improving dough handling, shelf-life, and sensory quality while maintaining consumer appeal. Full article
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14 pages, 2649 KiB  
Article
Study on the Liquid Transport on the Twisted Profile Filament/Spun Combination Yarn in Knitted Fabric
by Yi Cui, Ruiyun Zhang and Jianyong Yu
Polymers 2025, 17(15), 2065; https://doi.org/10.3390/polym17152065 - 29 Jul 2025
Viewed by 214
Abstract
The excellent moisture transport properties of yarns play a crucial role in improving the liquid moisture transfer behavior within textiles and maintaining their thermal-wet comfort. However, the current research on the moisture management performance of fabrics made from yarns with excellent liquid transport [...] Read more.
The excellent moisture transport properties of yarns play a crucial role in improving the liquid moisture transfer behavior within textiles and maintaining their thermal-wet comfort. However, the current research on the moisture management performance of fabrics made from yarns with excellent liquid transport properties primarily compares the wicking results, without considering the varying requirements of testing conditions due to differences in human sweating rates during daily activities. Moreover, the understanding of moisture transport mechanisms in yarns within fabrics under different testing conditions remains insufficient. In this study, two types of twisted combination yarns, composed of hydrophobic profiled polyester filaments and hydrophilic spun yarns to form a hydrophobic-hydrophilic gradient along the axial direction of the yarn, were developed and compared with profiled polyester filaments to understand the liquid migration behaviors in the knitted fabrics formed by these yarns. Results showed that hydrophobic profiled polyester filament yarn demonstrated superior liquid transport performance with infinite saturated liquid supply (vertical wicking test). In contrast, the twisted combination yarns exhibited better moisture diffusion properties under limited liquid droplet supply conditions (droplet diffusion test and moisture management test). These contradictory findings indicated that the amount of liquid moisture supply in testing conditions significantly affected the moisture transport performance of yarns within fabrics. It was revealed that the liquid moisture in the twisted combination yarns migrated through capillary wicking for moisture transfer. Under an infinite saturated liquid supply condition, the higher the content of hydrophilic fibers in the spun yarns, the greater the amount of moisture transferred, demonstrating an excellent liquid transport performance. Under the limited liquid droplet supply conditions, both the volume of liquid water and the moisture absorption capacity of the yarn jointly influence internal moisture migration within the yarn. It provided a theoretical reference for testing the internal moisture wicking performance of fabrics under different states of human sweating. Full article
(This article belongs to the Section Polymer Applications)
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29 pages, 42729 KiB  
Article
Sustainable and Functional Polymeric Coating for Wood Preservation
by Ramona Marina Grigorescu, Rodica-Mariana Ion, Lorena Iancu, Sofia Slamnoiu-Teodorescu, Anca Irina Gheboianu, Elvira Alexandrescu, Madalina Elena David, Mariana Constantin, Iuliana Raut, Celina Maria Damian, Cristian-Andi Nicolae and Bogdan Trica
Coatings 2025, 15(8), 875; https://doi.org/10.3390/coatings15080875 - 25 Jul 2025
Viewed by 331
Abstract
The development of sustainable and functional nanocomposites has attracted considerable attention in recent years due to their broad spectrum of potential applications, including wood preservation. Also, a global goal is to reuse the large volumes of waste for environmental issues. In this context, [...] Read more.
The development of sustainable and functional nanocomposites has attracted considerable attention in recent years due to their broad spectrum of potential applications, including wood preservation. Also, a global goal is to reuse the large volumes of waste for environmental issues. In this context, the aim of the study was to obtain soda lignin particles, to graft ZnO nanoparticles onto their surface and to apply these hybrids, embedded into a biodegradable polymer matrix, as protection/preservation coating for oak wood. The organic–inorganic hybrids were characterized in terms of compositional, structural, thermal, and morphological properties that confirm the efficacy of soda lignin extraction and ZnO grafting by physical adsorption onto the decorating support and by weak interactions and coordination bonding between the components. The developed solution based on poly(3-hydroxybutyrate-co-3-hydroxyvalerate) and lignin-ZnO was applied to oak wood specimens by brushing, and the improvement in hydrophobicity (evaluated by water absorption that decreased by 48.8% more than wood, humidity tests where the treated sample had a humidity of 4.734% in comparison with 34.911% for control, and contact angle of 97.8° vs. 80.5° for untreated wood) and UV and fungal attack protection, while maintaining the color and aspect of specimens, was sustained. L.ZnO are well dispersed into the polymer matrix, ensuring a smooth and less porous wood surface. According to the results, the obtained wood coating using both a biodegradable polymeric matrix and a waste-based preservative can be applied for protection against weathering degradation factors, with limited water uptake and swelling of the wood, UV shielding, reduced wood discoloration and photo-degradation, effective protection against fungi, and esthetic quality. Full article
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26 pages, 3891 KiB  
Article
Investigation of Hollow Block Production by Substituting Chicken Feather, Cotton and Rock Wool Waste Fibers for Pumice Aggregate
by Ela Bahsude Gorur Avsaroglu
Buildings 2025, 15(15), 2587; https://doi.org/10.3390/buildings15152587 - 22 Jul 2025
Viewed by 278
Abstract
Currently, natural resources are rapidly depleting as a result of increasing construction facilities. Increasing energy consumption with increasing construction is another serious issue. In addition, many problems that threaten the environment and human health arise during the disposal and storage of waste materials [...] Read more.
Currently, natural resources are rapidly depleting as a result of increasing construction facilities. Increasing energy consumption with increasing construction is another serious issue. In addition, many problems that threaten the environment and human health arise during the disposal and storage of waste materials obtained in different sectors. The main objective of this study is to investigate the substitution of cotton (CW), chicken feather (CFF) and stone wool waste (SWW) from pumice aggregate in the production of environmentally friendly hollow blocks. To achieve this, CW, CFF and SWW were substituted for pumice at ratios of 2.5–5–7.5–10% in mass, and hollow blocks were produced with this mixture under low pressure and vibrations in a production factory. Various characterization methods, including a size and tolerance analysis, unit volume weight test, thermal conductivity test, durability test, water absorption test and strength tests, were carried out on the samples produced. This study showed that waste fibers of chicken feather and stone wool are suitable for the production of sustainable and environmentally friendly hollow blocks that can reduce the dead load of the building, have sufficient strength, provide energy efficiency due to low thermal conductivity and have a high durability due to a low water absorption value. Full article
(This article belongs to the Section Building Materials, and Repair & Renovation)
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26 pages, 4992 KiB  
Article
Composites from Recycled HDPE and ZnO Nanopowder with Improved Insulation and Weathering Features for Cable Jacketing Applications
by Alina Ruxandra Caramitu, Magdalena Valentina Lungu, Romeo Cristian Ciobanu, Ioana Ion, Eduard Marius Lungulescu, Gabriela Beatrice Sbarcea, Virgil Emanuel Marinescu, Sebastian Aradoaei, Mihaela Aradoaei and Raducu Machidon
Polymers 2025, 17(14), 1987; https://doi.org/10.3390/polym17141987 - 20 Jul 2025
Viewed by 380
Abstract
In this study, polymer matrix composites based on high-density polyethylene (HDPE) and recycled HDPE (HDPEr) were reinforced with zinc oxide nanoparticles (ZnO NPs). Four formulations (M1-M4) with HDPE/HDPEr/ZnO NP mass ratios of 50/50/0, 48/47/5, 45/45/10, and 43/42/15 were produced via melt injection molding. [...] Read more.
In this study, polymer matrix composites based on high-density polyethylene (HDPE) and recycled HDPE (HDPEr) were reinforced with zinc oxide nanoparticles (ZnO NPs). Four formulations (M1-M4) with HDPE/HDPEr/ZnO NP mass ratios of 50/50/0, 48/47/5, 45/45/10, and 43/42/15 were produced via melt injection molding. Disc-shaped samples (Ø30 ± 0.1 mm × 2 ± 0.1 mm) were evaluated in unaged and aged states (840 h at 100% humidity and 100 °C) using scanning electron microscopy, X-ray diffraction, ultraviolet–visible and Fourier-transform infrared spectroscopy, water absorption, thermal resistance, and mechanical and dielectric testing. Among all composites, M2 showed the best performance, with the highest aging resistance (estimated lifetime of 3891 h in humidity and 2361 h in heat). It also exhibited superior mechanical properties, with the highest indentation hardness, Vickers hardness, and elastic modulus before (0.042 GPa, 3.846 HV, and 0.732 GPa) and after aging under humidity (0.042 GPa, 3.932 HV, 0.706 GPa) and elevated temperature (0.085 GPa, 7.818 HV, 1.871 GPa). Although ZnO NPs slightly reduced electrical resistivity, M2 showed the most stable dielectric properties. In its unaged state, M2 had 22%, 30%, and 3% lower surface resistivity, volume resistivity, and dielectric strength, respectively, than M1 polymer. M2 was identified as the optimal formulation, combining mechanical strength, dielectric stability, and resistance to moisture and heat. Full article
(This article belongs to the Section Polymer Composites and Nanocomposites)
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13 pages, 7783 KiB  
Article
Enhancing Metakaolin-Based Geopolymer Mortar with Eggshell Powder and Fibers for Improved Sustainability
by Demet Yavuz
Buildings 2025, 15(14), 2526; https://doi.org/10.3390/buildings15142526 - 18 Jul 2025
Viewed by 264
Abstract
This research explores the effectiveness of eggshell powder (ESP) and polypropylene (PP) fiber in geopolymer (GP) mortars. It examines how various doses of ESP, ranging from 0% to 25%, and two volumes of PP fibers, at 0.1% and 0.2% (by volume), impact the [...] Read more.
This research explores the effectiveness of eggshell powder (ESP) and polypropylene (PP) fiber in geopolymer (GP) mortars. It examines how various doses of ESP, ranging from 0% to 25%, and two volumes of PP fibers, at 0.1% and 0.2% (by volume), impact the workability, mechanical and physical characteristics, and microstructure of GP mortars. Assessments were made for workability, apparent porosity, water absorption, and flexural and compressive strengths, along with microstructural evaluations. Using ESP as a substitute for metakaolin (MK) at 15% and 25% (by weight) improved the flexural and compressive strengths by 22.9%, 22.5%, 37.1%, and 50.7%, respectively. Using PP fiber resulted in flexural strength improvements of up to 97%. These findings deepen the understanding of ESP’s potential as a partial replacement for MK in geopolymer mortar, provide insights on material enhancement, and demonstrate superior mechanical and durability properties. Full article
(This article belongs to the Section Building Materials, and Repair & Renovation)
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13 pages, 1060 KiB  
Article
Study on Injection Allocation Technology of Layered Water Injection in Oilfield Development
by Xianing Li, Bing Hou, He Liu, Hao Guo and Jiqun Zhang
Energies 2025, 18(13), 3502; https://doi.org/10.3390/en18133502 - 2 Jul 2025
Viewed by 193
Abstract
Reservoir heterogeneity, fluid property variations, and permeability contrasts across different geological layers result in significant disparities in water absorption capacities during oilfield development, often leading to premature water breakthrough, uneven sweep efficiency, and suboptimal waterflooding outcomes. The accurate determination of layer-specific water injection [...] Read more.
Reservoir heterogeneity, fluid property variations, and permeability contrasts across different geological layers result in significant disparities in water absorption capacities during oilfield development, often leading to premature water breakthrough, uneven sweep efficiency, and suboptimal waterflooding outcomes. The accurate determination of layer-specific water injection volumes is critical to addressing these challenges. This study focuses on a study area in China, employing comprehensive on-site investigations to evaluate the current state of layered water injection practices. The injection allocation strategy was optimized using a hybrid approach combining the splitting coefficient method and grey correlation analysis. Key challenges identified in the study area include severe reservoir heterogeneity, poor injection–production correspondence, rapid water cut escalation, and low recovery rates. Seven dominant influencing factors—the sedimentary microfacies coefficient, effective thickness, stimulation factor, well spacing, permeability, connectivity, and permeability range coefficient—were identified through grey correlation analysis. Field application of the proposed method across fourteen wells demonstrated significant improvements: a monthly oil production increase of 40 tons, a water production reduction of 399.24 m3/month, and a 2.45% decline in the water cut. The obtained results substantiate the method’s capability in resolving interlayer conflicts, optimizing oil recovery performance, and effectively controlling water channeling problems. Full article
(This article belongs to the Section H: Geo-Energy)
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18 pages, 5967 KiB  
Article
Incorporation of Poly (Ethylene Terephthalate)/Polyethylene Residue Powder in Obtaining Sealing Concrete Blocks
by Ana Paula Knopik, Roberta Fonseca, Rúbia Martins Bernardes Ramos, Pablo Inocêncio Monteiro, Wellington Mazer and Juliana Regina Kloss
Processes 2025, 13(7), 2050; https://doi.org/10.3390/pr13072050 - 28 Jun 2025
Viewed by 350
Abstract
Polymer residues can be reused in civil construction by partially replacing mineral aggregates in concrete, thereby reducing the extraction of natural resources. This study aimed to evaluate the use of powdered poly (ethylene terephthalate) (PET) and polyethylene (PE) residues, accumulated in shaving-mill filters [...] Read more.
Polymer residues can be reused in civil construction by partially replacing mineral aggregates in concrete, thereby reducing the extraction of natural resources. This study aimed to evaluate the use of powdered poly (ethylene terephthalate) (PET) and polyethylene (PE) residues, accumulated in shaving-mill filters during the extrusion of multilayer films used in food packaging, in the production of sealing masonry blocks. The PET/PE residues were characterized by Fourier Transform Infrared Spectroscopy (FTIR), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). Cylindrical specimens were produced in which part of the sand, by volume, was replaced with 10, 20, 30, 40 and 50% polymer residue. The cylindrical specimens were evaluated for specific mass, water absorption and axial and diametral compressive strengths. The 10% content provided the highest compressive strength. This formulation was selected for the manufacture of concrete blocks, which were evaluated and compared with the specifications of ABNT NBR 6136:2014. The concrete blocks showed potential for applications without structural function and were classified as Class C. The results, in line with previous investigations on the incorporation of plastic waste in concrete, underscore the promising application potential of this strategy. Full article
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24 pages, 1909 KiB  
Article
Experimental Investigation into Waterproofing Performance of Cement Mortar Incorporating Nano Silicon
by Nasiru Zakari Muhammad, Muhd Zaimi Abd Majid, Ali Keyvanfar, Arezou Shafaghat, Ronald MCcaffer, Jahangir Mirza, Muhammad Magana Aliyu and Mujittafa Sariyyu
Buildings 2025, 15(13), 2227; https://doi.org/10.3390/buildings15132227 - 25 Jun 2025
Viewed by 459
Abstract
Water ingress and penetration of aggressive fluids undermines the integrity of many concrete structures. For this reason, optimal performance of such structures up to their designed life cannot be guaranteed. This study introduces nano silicon as an alternative waterproofing admixture for increasing life [...] Read more.
Water ingress and penetration of aggressive fluids undermines the integrity of many concrete structures. For this reason, optimal performance of such structures up to their designed life cannot be guaranteed. This study introduces nano silicon as an alternative waterproofing admixture for increasing life span of cementitious materials, due to its non-vulnerability to deterioration, which is common to traditional surface coating solutions. Therefore, nano silicon was characterized using Field Emission Scanning Electron Microscope (FESEM), Energy Dispersion Spectroscopy (EDS), Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), and surface Zeta potential. The Central Composite Design (CCD) tool was adopted to plan the experiment and further used to model the relationship between experimental variables and experimental response. The model was found to be nonlinear quadratic based on Analysis of Variance (ANOVA). Also, the validity of the model was evaluated and found to have accurate prediction with mean absolute percentage error (MAPE) of 1.62%. The optimum mix ratio necessary to increase resistance to capillary water absorption was established at a nano silicon dosage of 6.6% by weight of cement and w/c of 0.42. In conclusion, the overall results indicate that resistance to capillary water absorption was increased by 62%. Furthermore, while gas permeability was reduced by 31%, on the other hand, volume of water permeable voids decreased by 10%. Full article
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15 pages, 3089 KiB  
Article
Influence of Carbonized Garbage Fly Ash on the Performance of Foam Concrete
by Di Wang, Zhiqiang Xu, Yehan Yu, Na Xu, Chuanqi Li, Xu Tian, Hui Wang, Feiting Shi and Kangshuo Xia
Coatings 2025, 15(7), 736; https://doi.org/10.3390/coatings15070736 - 20 Jun 2025
Viewed by 449
Abstract
To utilize garbage fly ash (GFA) as a resource, this research proposes a method for preparing GFA with higher reactivity through carbonation and applies it to the production of foamed concrete. The effects of CO2-cured GFA substitution rate and foam volume [...] Read more.
To utilize garbage fly ash (GFA) as a resource, this research proposes a method for preparing GFA with higher reactivity through carbonation and applies it to the production of foamed concrete. The effects of CO2-cured GFA substitution rate and foam volume on slump flow, rheological properties, mechanical strength, thermal conductivity, water absorption rate, and water resistance coefficient of foam concrete are clarified. The results show that an increase in the CO2-cured GFA substitution rate from 0 to 100% improves the slump flow by 10.8%~34.5% and decreases the plastic viscosity by 4.8%~36.4% and yield stress by 5.6%~28.1%. The higher carbonized GFA substitution rate can prolong the initial setting time with the largest amplitude of 30.4%. In addition, increasing the CO2-cured GFA substitution rate improves the mechanical strengths, water resistance, thermal conductivity, and solidification of heavy metals. When the CO2-cured GFA substitution rate is 100%, the 28-day compressive strength, 28-day flexural strength, water absorption rate, water resistance coefficient, thermal conductivity, leached Zn, and leached Cr of foam concrete are 18 MPa, 3.6 MPa, 20.7%, 0.46, 0.69 W·m−1·K−1, 9.4 × 10−5 mg/mL, and 8.6 × 10−5 mg/mL, respectively. Moreover, more foam volume improves the fresh-mixed performance of foam concrete while reducing the mechanical strength, water resistance property, thermal conductivity, and solidification of heavy metals. It is found that the technical approach for preparing foamed concrete containing CO2-cured GFA with 40% foam volume can achieve its large-scale use. Full article
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23 pages, 8462 KiB  
Article
Engineering and Durability Properties of Sustainable Bricks Incorporating Lime Kiln Dust, Ground Granulated Blast Furnace Slag, and Tyre Rubber Wastes
by Joy Ayankop Oke and Hossam Abuel-Naga
Buildings 2025, 15(12), 2079; https://doi.org/10.3390/buildings15122079 - 17 Jun 2025
Viewed by 378
Abstract
This study explores the potential of using sustainable materials in brick manufacturing by designing a novel brick mix in the laboratory, incorporating sand, lime kiln dust (LKD) waste, tyre rubber, and ground granulated blast furnace slag (GGBFS) waste. These cementless bricks blended LKD–GGBFS [...] Read more.
This study explores the potential of using sustainable materials in brick manufacturing by designing a novel brick mix in the laboratory, incorporating sand, lime kiln dust (LKD) waste, tyre rubber, and ground granulated blast furnace slag (GGBFS) waste. These cementless bricks blended LKD–GGBFS wastes as the binder agent and fine crumb rubber from waste tyres as a partial replacement for sand in measured increments of 0%, 5%, and 10% by volume of sand. Ordinary Portland cement (OPC) and fired clay bricks were sourced from the industry, and their properties were compared to those of the laboratory bricks. Tests performed on the industry and laboratory bricks included compressive strength (CS), freeze-thaw (F-T), and water absorption (WA) tests for comparison purposes. Additionally, scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) analyses were performed on the bricks to assess the morphological and mineralogical changes responsible for the observed strengths and durability. The CS and WA values of the engineered bricks were 12, 6, and 4 MPa, and 7, 12, and 15%, respectively, for 0, 5, and 10% crumb rubber replacements. The industry bricks’ average CS and WA values were 13 MPa and 8%, respectively. From the results obtained, the green laboratory bricks passed the minimum strength requirements for load-bearing and non-load-bearing bricks, which can be used to construct small houses. Lastly, the engineered bricks demonstrated strength and durability properties comparable to those of the industry-standard bricks, indicating their potential as a sustainable alternative to help divert waste from landfills, reduce the pressure on natural fine sand extraction, and support eco-conscious brick production for a sustainable environment. Full article
(This article belongs to the Section Building Materials, and Repair & Renovation)
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15 pages, 5199 KiB  
Article
Biodegradable, Wear-Resistant and Resilient Thermoplastic Polycarbonate-Based Polyurethane with Nanoscale Microphase Structure
by Shuang Su, Jintao Wang, Qi Yan, Anqi Li, Chuang Liu, Xianli Wu and Yuezhong Meng
Polymers 2025, 17(12), 1665; https://doi.org/10.3390/polym17121665 - 16 Jun 2025
Viewed by 498
Abstract
A series of PPCDL-PEG1000-TPU were prepared by melting method using CO2 based biodegradable polycarbonate diol (PPCDL) and polyethylene glycol (PEG1000) as soft segments, and hexamethylene diisocyanate (HDI) and 1,4-butanediol (BDO) as hard segments. Their structure and properties were characterized to [...] Read more.
A series of PPCDL-PEG1000-TPU were prepared by melting method using CO2 based biodegradable polycarbonate diol (PPCDL) and polyethylene glycol (PEG1000) as soft segments, and hexamethylene diisocyanate (HDI) and 1,4-butanediol (BDO) as hard segments. Their structure and properties were characterized to show that the products have nanoscale microphase separation, excellent wear-resistance and high resilience. PPCDL-PEG1000-TPUs have high tensile strength, high elongation at break, controllable hardness and excellent wear resistance when the content of hard segment is about 20%. Compared to PPCDL-TPU with only PPCDL as soft segment, the mechanical properties of TPU increase rather than decrease after the addition of PEG due to the crystallization behavior of PEG units in block copolymers. When the ratios of nPPCDL:nPEG are 10:1 and 4:1, the tensile strength of PPCDL-PEG1000-TPU reaches 27.5 MPa and 16.5 MPa (an increase of nearly 200% and 20% than PPCDL-TPU). The elongation at break reaches 1995% and 2485% (an increase of nearly 40% and 75% than PPCDL-TPU). Hardness of the prepared PPCDL-PEG1000-TPUs’ Shore A can be controlled in range of 70~85 by regulating the addition of PEG and their glass transition temperature (Tg) decreases with the increase of the amount of PEG incorporated. All PPCDL-PEG1000-TPUs exhibit good wear resistance with the average Akron wear volume of 12 mm3 after 4000 cycles of experiments according to national standards. PPCDL-PEG1000-TPUs show a high resilience performance with a negligible change in the hysteresis loop area after six cycles of tensile stretching. Furthermore, all PPCDL-PEG1000-TPUs possess high thermal stability, strong hydrophobicity, and low water absorption. This material has excellent application prospects and competitiveness in footwear and shock-absorbing materials. Full article
(This article belongs to the Section Polymer Analysis and Characterization)
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22 pages, 10230 KiB  
Article
Near-Surface Water Vapor Content Based on SPICAV IR/VEx Observations in the 1.1 and 1.18 μm Transparency Windows of Venus
by Daria Evdokimova, Anna Fedorova, Nikolay Ignatiev, Oleg Korablev, Franck Montmessin and Jean-Loup Bertaux
Atmosphere 2025, 16(6), 726; https://doi.org/10.3390/atmos16060726 - 15 Jun 2025
Cited by 1 | Viewed by 415
Abstract
The SPICAV IR spectrometer aboard the Venus Express orbiter measured spectra of the 1.1 and 1.18 μm atmospheric transparency windows at the Venus night side in 2006–2014. The long-term measurements encompassed the major part of the Venus globe, including polar latitudes. For the [...] Read more.
The SPICAV IR spectrometer aboard the Venus Express orbiter measured spectra of the 1.1 and 1.18 μm atmospheric transparency windows at the Venus night side in 2006–2014. The long-term measurements encompassed the major part of the Venus globe, including polar latitudes. For the first time, the H2O volume mixing ratio in the deep Venus atmosphere at about 10–16 km has been retrieved for the entire SPICAV IR dataset using a radiative transfer model with multiple scattering. The retrieved H2O volume mixing ratio is found to be sensitive to different approximations of the H2O and CO2 absorption lines’ far wings and assumed surface emissivity. The global average of the H2O abundance retrieved for different parameters ranges from 23.6 ± 1.0 ppmv to 27.7 ± 1.2 ppmv. The obtained values are consistent with recent studies of water vapor below the cloud layer, showing the H2O mixing ratio below 30 ppmv. Within the considered dataset, the zonal mean of the H2O mixing ratio does not vary significantly from 60° S to 75° N, except for a 2 ppmv decrease noted at high latitudes. The H2O local time distribution is also uniform. The 8-year observation period revealed no significant long-term trends or periodicities. Full article
(This article belongs to the Section Planetary Atmospheres)
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