Water Absorption Rate Research Articles

Oil-based drilling cutting pyrolysis residues- phosphogypsum foamed ceramics: Basic properties, microsintering mechanism and heavy metals solidification

Oil-based drilling cutting pyrolysis residues(ODPR) and phosphogypsum(PG) are typical types of industrial solid waste in China, characterized by low utilization rate and high output. The large amount of untreated accumulation will release heavy metals(HMs) and other pollutants, posing risks to the environment. Therefore, there is an urgent need to develop a high value-added building material product that can reduce environmental hazards while improving utilization rate. Based on this background, this study uses ODPR and PG as raw materials to explore their potential applications in the field of foamed ceramics. Research has shown that different sintering processes have a significant impact on the appearance and performance of products. By adjusting the preparation process, foamed ceramic products with excellent performance can be prepared. When the sintering temperature is 925℃, the foaming agent dosage is 3 %, and the raw material ratio ODPR:PG:Borax=35:45:20, a foamed ceramic product with a porosity of 60.95 %, water absorption rate of 3.4 %, compressive strength of 4.8 MPa, thermal conductivity of 0.8016 W/(m·k), and acid and alkali resistance of 98.57 % and 99.44 % can be prepared. The product meets the relevant requirements of “Fired heat preservation brick and block (GB/T 26538)” and “ General Specification for porous ceramic products (GB/T 16533)”. The HMs content test showed that the Ni and Pb contents in the pre-sintered blanks were the highest, at 0.6308 mg/kg and 0.3182 mg/kg, respectively. However, after high-temperature calcination, the solidification rate of HMs could reach up to 98.93 %, and the leaching amount was significantly reduced. The three further evaluation methods indicate that HMs in the pre-sintered blanks and foamed ceramic products do not pose significant ecological risks. The research results provide a green inorganic insulation material in the field of solid waste control and building materials.

Non-sintered ceramsite from alkali-activated gasification slag for adsorption through the regulation of physical properties and pore structure

With the development of the coal gasification industry, the comprehensive utilization of coal gasification fine slag (CGFS) has become increasingly important. This study explored the potential of producing non-sintered ceramsite by combining CGFS with blast furnace slag (BFS). The impacts of the alkali activator modulus, dosage, and BFS-CGFS ratio on the ceramsite's cylinder compressive strength, bulk density, apparent density, water adsorption ratio, hydration products, microstructure, and adsorption capacity were investigated. Moreover, the leaching behavior of heavy metals in acidic environments and the production costs were evaluated. The results indicated that the modulus and dosage of the alkali activator, along with the BFS-CGFS ratio, significantly affected the properties of the ceramsite. The cylinder compressive strength, bulk density, and apparent density of the ceramsite increased with the increase in the alkali activator dosage and modulus, but decreased as the BFS-CGFS ratio decreased. The water absorption rate behaved oppositely. With increasing alkali activator modulus and dosage, the ceramsite's adsorption capacity for iodine, CODCr, and methylene blue first increased and then decreased, peaking at a modulus of 1.4 and a dosage of 12%, respectively. A reduced BFS-CGFS ratio increased the adsorption capacity of the ceramsite for iodine and CODCr. Considering both mechanical and adsorption properties, the optimal composition for the ceramsite was found to be an alkali activator modulus of 1.4, a dosage of 12%, and a CGFS content of 70%. With this ratio, the use of ceramsite would not result in secondary environmental pollution. This study not only provided a new approach to enhance the utilization of CGFS but also avoided the use of calcination processes in producing ceramsite, demonstrating its potential in reducing environmental impact.

Effects of aggregates and fibers on the strength and permeability of concrete exposed to low vacuum environment

The performance and regulation of concrete in low vacuum environments are receiving increasing attention. This study investigates the effects of aggregates and fibers on the strength and permeability of concrete in a low vacuum environment, using varying gradients of sand ratios (37.5 %, 40 %, and 42 %) and aggregate-to-binder ratios (3.27, 3.92, and 4.14). Three types of non-metallic fibers are utilized: polyethylene (PE), polyvinyl alcohol (PVA), and glass fibers. Evaluations focus on concrete strength, mass loss, gas permeability, capillary water absorption, and porosity. Results indicate that higher sand and aggregate-to-binder ratios enhance both flexural and compressive strength. Fiber incorporation improves flexural and compressive toughness, with PE fibers showing the most significant toughening effect. The low vacuum environment increases the strength of the concrete but reduces its axial compression toughness ratio and increases brittleness, while fiber incorporation helps improve the compression toughness of the concrete. Higher sand and aggregate-to-binder ratios reduce mass loss and accelerate drying equilibrium, while fibers increase mass loss and prolong drying equilibrium, with PVA fibers causing greater mass loss. The pattern of concrete mass loss can be explained by the tortuosity of the moisture diffusion path. Additionally, low vacuum significantly increases the gas permeability of concrete. Enhancing the sand and aggregate-to-binder ratios reduces permeability both before and after low vacuum treatment. Although fibers increase the gas permeability, they help mitigate this increase under low vacuum condition. Capillary water absorption tests reveal that concrete under low vacuum condition has a significantly higher water absorption rate compared to air-drying condition. Increasing sand and aggregate-to-binder ratios reduces water absorption and capillary water content, whereas fibers have the opposite effect. Porosity tests show that moisture migration in a low vacuum environment is mainly related to permeable porosity, while total porosity is more closely related to compressive strength.

Inovasi Paving Block Bentuk Ikan Pari

The weak interlock system in paving blocks can cause discomfort for drivers when passing over them. The more frequently traversed by vehicles, paving blocks with poor interlock systems will experience displacement. The compressive strength of paving blocks also affects their quality, thus supporting the performance of the paving block interlock system. This research aims to produce paving block products with a better interlocking system. The method used in this research is experimental and conducted in a laboratory setting. The results of the compressive strength test on stingray-shaped paving blocks, conducted at 14 days and converted to 28 days, showed superior compressive strength with an average of 24.04 MPa compared to conventional square and hexagonal paving blocks tested at 28 days, each with an average compressive strength of 20.07 MPa and 22.25 MPa, respectively. The water absorption test of the stingray-shaped paving blocks conducted at 7 and 14 days showed average water absorption rates of 5.67% and 4.31%, respectively, meeting the quality requirements of Grade B according to SNI -03-0691-1996, which requires less than 6%. Interlock system testing of the stingray-shaped paving blocks indicated superiority with an average displacement of 5.514 mm compared to conventional square and hexagonal paving blocks, each with an average displacement of 11.802 mm and 9.744 mm, respectively. The cost calculation for stingray-shaped paving blocks amounted to Rp. 2263.22 per paving block, 24,559% more economical than the total cost for conventional hexagonal paving blocks, which amounted to Rp. 3000.00.

Characterization and ceramic properties evaluation of Lombok clay

Purpose. This research aims to assess the characteristics of ceramics made from Lombok clay to optimize the quality of ceramic products in the Lombok region and surrounding areas. Methods. Methods used to characterize Lombok clay include measuring its chemical composition, loss on ignition, plasticity level and conducting mineral analysis. Additionally, the influence of sintering temperature on clay properties and shrinkage is studied. Findings. The main mineral component of Lombok clay is kaolin, which has a high level of plasticity and a water absorption rate of 7 ± 0.6%. The ceramic body produced from this clay is classified as semi-porcelain, making it suitable for medium-sized tableware manufactured using the rotating technique. Originality. This research highlights the effect of sintering temperature on the mineral transformation of Lombok clay and provides valuable information on its optimal applications. It fills a gap in the literature by providing comprehensive data on clay properties and optimal processing conditions that have previously been underexplored. Practical implications. Lombok clay is used predominantly by small-scale ceramic craftsmen in Lombok and Bali due to its relatively low market price. With the findings of this study, these craftsmen can enhance the quality of their products to semi-porcelain standards by adjusting the sintering temperature.

Highly Deformable and Robust Ionic Structure for Multi‐Tissue Adaptive Hemostatic Sponges

AbstractAccidental trauma is always accompanied by tissue defects with noncompressible hemorrhages. Deformable and tough biomaterials are desirable for self‐compressible hemostasis, although their preparation is challenging. Here, a critical‐size calcium phosphate (C–CaP) with polymer‐like high deformability and mineral‐like high bending strength is prepared, which is hybridized with silk fibroin (SF) to fabricate a hemostatic sponge (SF‐C). C–CaP endows SF‐C with an ultrahigh elastic modulus (36.0 kPa) among analogous materials, leading to an ultrafast water absorption rate (1.2 g cm−3 s−1) and space‐filling rate (200.0%/s). The deformability of the SF‐C sponge further enables self‐adaptability to defects with micrometre‐scale precision. Consequently, SF‐C achieves rapid hemostasis in both damaged soft tissues and hard tissues in rats, resulting in less blood loss and a shorter hemostatic time than those of clinical materials. This study provides a promising hemostatic material for the treatment of hemorrhages in defective tissues and expands the current knowledge by revealing the critical‐sized ionic structure and unique mechanics of C–CaP.

A multifunctional Mg2Si5Al4O18/Y2Si2O7 glass-ceramic coating for porous Si3N4 ceramic

In order to enhance the oxidation and moisture resistance of porous Si3N4 ceramics, here we design a novel Y2O3-MgO-Al2O3-SiO2 glass-ceramic coating through a straightforward scraping process followed by sintering method. The crystalline phase, water absorption, dielectric properties and high temperature resistance of the coating are evaluated systematically. The result shows that the coating obtained by sintering at 1200 °C for 30 min exhibits high density, with an approximate thickness of 88 ± 5 μm. The crystalline phases present in the coating are composed of Mg2Si5Al4O18 and Y2Si2O7. The water absorption rate of the coating is only 0.59 %, and its dielectric constant ranges from 3.3 to 3.4 in the frequency range of 2–20 GHz, with a low dielectric loss tangent below 4 × 10−3. After exposure to high-temperature (1000 °C for 30 min), no significant changes are observed in the microstructure or water absorption rate of the coating. Therefore, this study has successfully developed a multifunctional glass-ceramic coating that is moisture-proof, high-temperature resistant, and exhibits low dielectric loss.

Optimization of mechanical properties of small diameter artificial blood vessels based on alginate/chitosan/gelatin

Due to the rise in cardiovascular disease and the problem of autologous transplant limitation, the emergence of 3D bioprinted blood vessels using natural polymer materials as ink is becoming increasingly important in the field of small-diameter artificial blood vessels (φ ≤ 6 mm). In this paper, gelatin was firstly adopted to explore alginate/chitosan composite hydrogel properties and solve the current issues of poor mechanical performance and suboptimal printability of small-diameter blood vessels, which indicated that the modification caused a 17.7 % increase in compressive strength and a 63.2 % enhancement in tensile properties. The material microstructure evaluation showed that the samples with gelatin(4 %) presented the excellent water absorption rate(>90 %) significantly increasing their porosities. A self-developed 3D bioprinter was utilized to clarify the controllable mechanism of small-diameter artificial blood vessel, which has superior performance and excellent printability. This study provides a new reference solution to the current challenges in the bio-ink performance and printability of small-diameter artificial blood vessels.

Improvement of the gel properties of curdlan gel by hydrogen bonding interaction with trehalose

This study investigated the effect of trehalose addition (0.5–2.0%) on the gelation properties of curdlan gels were investigated. The results demonstrated that the optimal gelation performance of curdlan-trehalose composite gel was determined at trehalose concentration of 1.0% with preferable water holding capacity, water absorption rate, and freeze-thaw stability. The gelation behavior of the curdlan-trehalose composite gel showed a more intense network structure with increasing storage modulus (G′), loss modulus (G″), and deceasing tan δ at the trehalose concentration in the range of 0%–1%. And the highest gel strength was also observed in 1% trehalose addition. Moreover, the structures characterized by Fourier transform infrared (FT-IR), X-ray diffraction (XRD), Low field nuclear magnetic resonance (LF-NMR) and scanning electron microscope analysis (SEM) all revealed that the addition of trehalose strengthened the hydrogen bonding interaction with curdlan to create a much denser network of composite gel, which would provide a better mechanistic insight of the curdlan-trehalose gel in practical application potentials in food and medicine.

Enhanced mechanical, thermal, water and UV aging resistance properties of bamboo fiber/HDPE composites through silane coupling agent modified nano-SiO2-TiO2

Nano-TiO2 is widely employed to enhance the properties of plant fiber reinforced thermoplastic polymer composites due to its chemical inertness, anti-aging, and anti-bacterial properties. However, the enhancement of bamboo fiber/high-density polyethylene (BF/HDPE) composites is limited by the high photocatalytic activity of nano-TiO2 and its poor compatibility with the BF/HDPE matrix. This study employs an organic-inorganic co-modification to prepare BF/HDPE composites reinforced with silane coupling agent KH550 modified nano-SiO2 coated nano-TiO2 (KH550/SiO2-TiO2) by spray coating and melt mixing methods, and the properties of the composites were tested and characterized. The effects of KH550 and KH550/SiO2-TiO2 content on the properties of modified BF/HDPE composites, including mechanical properties, water absorption, thickness swelling rate, water contact angle, thermal stability, and UV aging resistance，which were characterized using methods of mechanical tests, FTIR, UV-Vis, XPS and SEM, both before and after modification. The results indicate that KH550 effectively improves the agglomeration phenomenon and enhances the dispersibility of nano-SiO2-TiO2 in the BF/HDPE composites. The optimal thermal stability is achieved when the BF/HDPE composites modified with a 5 wt% KH550/SiO2-TiO2, while BF/HDPE composites modified with a 3 wt% KH550/SiO2-TiO2 exhibit the better mechanical properties, water resistance, and UV aging resistance compared to other contents. Flexural strength and modulus of KH550/SiO2-TiO2 modified BF/HDPE composites increased by 18.71 % and 17.92 %, tensile strength and modulus increased by 7.74 % and 21.92 %, respectively. The 480-hour water absorption and thickness swelling rate decreased by 18.68 % and 20.73 %, respectively, and the contact angle increased by 19.17°; better thermal stability and color stability was observed. The spray coating method was more effective in improving the properties of the modified BF/HDPE composites than the melt mixing method. Comprehensive analysis indicates that the mechanical properties, water resistance, thermal stability, and UV aging resistance of the BF/HDPE composites reinforced with 3 wt% KH550/SiO2-TiO2 prepared by the spray coating method are significantly enhanced.

Enhanced Water Resistance of TiO2-GO-SMS-Modified Soil Composite for Use as a Repair Material in Earthen Sites.

Most earthen sites are located in open environments eroded by wind and rain, resulting in spalling and cracking caused by shrinkage due to constant water absorption and loss. Together, these issues seriously affect the stability of such sites. Gypsum-lime-modified soil offers relatively strong mechanical properties but poor water resistance. If such soil becomes damp or immersed in water, its strength is significantly reduced, making it unviable for use as a material in the preparation of earthen sites. In this study, we achieved the composite addition of a certain amount of sodium methyl silicate (SMS), titanium dioxide (TiO2), and graphene oxide (GO) into gypsum-lime-modified soil and analyzed the microstructural evolution of the composite-modified soil using characterization methods such as XRD, SEM, and EDS. A comparative study was conducted on changes in the mechanical properties of the composite-modified soil and original soil before and after immersion using water erosion, unconfined compression (UCS), and unconsolidated undrained (UU) triaxial compression tests. These analyses revealed the micro-mechanisms for improving the waterproof performance of the composite-modified soil. The results showed that the addition of SMS, TiO2, and GO did not change the crystal structure or composition of the original soil. In addition, TiO2 and GO were evenly distributed between the modified soil particles, playing a positive role in filling and stabilizing the structure of the modified soil. After being immersed in water for one hour, the original soil experienced structural instability leading to collapse. While the water absorption rate of the composite-modified soil was only 0.84%, its unconfined compressive strength was 4.88 MPa (the strength retention rate before and after immersion was as high as 93.1%), and the shear strength was 614 kPa (the strength retention rate before and after immersion was as high as 96.7%).

EVALUATION OF PROPERTIES OF WOOD PLASTIC COMPOSITES MADE FROM SEVEN TYPES OF LIGNOCELLULOSIC FIBERS

This article aims to investigate the characteristics of wood plastic composites (WPC) prepared from polyethylene (PE) reinforced with lignocellulosic fibers derived from the xylem and bark of Masson pine, fir, cypress, as well as from Moso bamboo. The surface polarity and elemental composition of fibers were determined through contact angle measurements and X-ray photoelectron spectroscopy (XPS). The lignocellulosic fiber/PE composites were manufactured through hot-pressing technique, and their water absorption, mechanical properties, and mildew resistance were evaluated. The results revealed that the surface free energy of xylem fibers was higher than that of bark fibers among the three conifer species. XPS analysis showed that the O/C ratio of bark was consistently lower than that of xylem fiber. Among the three conifers, the Masson pine bark had the lowest O/C ratio (22.25%), while its xylem fibers had the highest ratio of 41.64%. WPC made with bark fibers had better water resistance. Additionally, the composites reinforced with xylem fibers showed superior static bending strength, impact strength, and mildew-resistant properties as compared to the composites reinforced with bark fibers. WPC made from bamboo fibers exhibited the best water resistance, with a water absorption rate and thickness swelling rate of 1.83% and 1.42%, respectively. They also had the highest static bending strength, elastic modulus, and impact strength, at 41.31 MPa, 3.82 GPa, and 10.24 kJ/m2, respectively. The WPC made from fir xylem fibers showed the most effective mildew resistance, with the smallest damage (0.50).

Enhancing Power and Thermal Gradient of Solar Photovoltaic Panels with Torched Fly-Ash Tiles for Greener Buildings

Solar photovoltaic (PV) panels that use polycrystalline silicon cells are a promising technique for producing renewable energy, although research on the cells’ efficiency and thermal control is still ongoing. This experimental research aims to investigate a novel way to improve power output and thermal performance by combining solar PV panels with burned fly-ash tiles. Made from burning industrial waste, torched fly ash has special qualities that make it useful for architectural applications. These qualities include better thermal insulation, strengthened structural integrity, and high energy efficiency. Our test setup shows that when solar PV panels are combined with torched fly-ash tiles, power generation rises by 7% and surface temperature decreases by 3% when compared to standard panels. The enhanced PV efficiency is ascribed to the outstanding thermal insulation properties of fly ash tiles and their capacity to control panel temperature. To ensure longevity and safety in building applications, the tiles employed in this study had a water absorption rate of 5.37%, flexural strength of 2.95 N/mm2, and slip resistance at 38 km/h. Furthermore, we find improved structural resilience and lower cooling costs when up to 30% of the sand in floor tiles is replaced with torched fly ash, which makes this method especially appropriate for sustainable buildings. Key performance indicators that show how effective these tiles are in maximizing energy use in buildings include thermal emissivity (0.874), solar reflectance (0.8), and solar absorption (0.256). While supporting more ecofriendly building techniques, this study highlights the advantages of utilizing burned fly ash in solar PV systems: enhanced power generation and thermal comfort. The main results open a greater potential for fly ash use in different building materials. The use of torched fly ash in building materials enhances thermal insulation and structural integrity while lowering cooling costs, making it an ideal choice for eco-friendly construction and highlighting the potential for further research into environmentally responsible, energy-efficient solutions.

Optimization of starch foam extrusion through PVA polymerization, moisture content control, and CMCS incorporation for enhanced antibacterial cushioning packaging

Melt strength and moisture content are critical parameters in starch foam extrusion, as they dictate bubble expansion dynamics, which subsequently determine the foam's properties. Despite continuous advancements in the development and application of starch foams, challenges such as water resistance, mechanical strength, and antibacterial activity remain unresolved. This research investigates the influence of polyvinyl alcohol (PVA) polymerization and moisture content on the properties of extruded foam while also exploring the potential for enhancing antimicrobial functionality by incorporating carboxymethyl chitosan (CMCS) into conventional starch foams. The findings underscore the significance of melt strength and intermolecular entanglements in shaping foam characteristics, confirming that bioactive components effectively improve hydrophobicity, foaming characteristics, and antibacterial capabilities. Moreover, by precisely regulating PVA polymerization and moisture content, it became feasible to optimize foam properties and achieve the desired performance. Specifically, foam with a moisture content of 12 % and a PVA polymerization degree of 1700 exhibited exceptional performance, including the highest foaming ratio of 45.62, the minimal water absorption rate of 6.31 %, and the greatest recovery rate of 88.95 %. Furthermore, increasing CMCS concentrations substantially enhances the antibacterial properties of the foam, demonstrating its potential for application in antibacterial cushioning packaging and emphasizing its versatility and practicality.

An eco-friendly strategy of cell wall stapling: In situ crosslinking of acrylic acid emulsion impregnated in thermally treated poplar wood

Traditional wood modification methods often result in the release of harmful substances and energy wastage. This study proposes an efficient and environmentally friendly modification strategy for fast-growing poplar wood. The approach involves polymerizing organic linear molecules within the cell wall to form stitches, thereby enhancing the dimensional stability and mechanical properties of wood and increasing its ability to withstand various environments. Poplar wood specimens were treated via a method that combines heat treatment with acrylic emulsion impregnation. The research findings indicated an improvement in the mechanical properties of poplar wood following the combined treatment. Moreover, poplar wood subjected to this treatment approach exhibited a 35.24 % lower water absorption rate after a 7-day water immersion test, and tangential and radial swelling rates of the wood were reduced by 29.66 % and 45.68 %, respectively. Scanning electron microscopy revealed excellent penetration of acrylic emulsion into wood cells; the emulsion infiltrated the wood and adhered to the cell walls, forming a crosslinked network structure. Analysis of the modification mechanism through X-ray diffraction, Fourier-transform infrared spectroscopy, and X-ray photoelectron spectroscopy showed that the successful infusion of acrylic emulsion compensated for the lower mechanical properties of thermally treated wood, thus improving the utilization value of poplar. The acrylic emulsion is an environmentally friendly and harmless modifier, making the modified wood suitable for various applications, including indoor furniture, logistics, and outdoor facilities. This modification strategy enables efficient resource utilization and provides valuable insights for the sustainable development of the timber industry.

Production of high-strength eco-conscious ceramics exclusively from municipal solid waste

This research investigated the application of municipal solid waste incineration fly ash (MSWIFA), municipal solid waste incineration bottom ash (MSWIBA), and construction waste residue (CWR) as raw materials for the comprehensive conversion into municipal solid waste ceramics employing the SiO2-Al2O3-CaO-MgO (8 wt%) phase diagram. This study aimed to evaluate the influence of the addition of MSWIFA and sintering temperature on important ceramics properties, including linear shrinkage, water absorption, sintering range, and flexural strength. Additionally, relationships were established among these physical parameters using Pearson's correlation coefficient. The thermal behavior of the mixture was analyzed through automatic slag melting point tester and TG-DSC techniques. Furthermore, characterization of the crystalline phase transition and microstructure of sintered samples was performed by XRD, Factsage, and SEM. The results showed that both the addition of MSWIFA and the sintering temperature significantly influenced the crystal phase composition of the sintered ceramics. Moreover, the addition of MSWIFA and the sintering temperature had a significant influence on the pore structure of the ceramics. These ceramics exhibited exceptional properties, such as the extremely low water absorption rate of 0.08 % and the remarkable flexural strength of 124.78 MPa. Ceramics performance indicators were far higher than the requirements of China's national standard GB/T4100-2015. The sintering range had the capability to attain 30 °C, guaranteeing the feasibility of practical manufacturing processes. Furthermore, leaching concentration tests conducted on additive-free ceramic samples reveal a low risk of heavy metal contamination, as the heavy metals were effectively solidified within the crystalline and amorphous phases of the ceramics. The comprehensive utilization of MSWIFA, MSWIBA, and CWR for the production of fully solid waste ceramics not only yields cost reduction benefits but also promotes efficient utilization, presenting a feasible and highly promising approach to sustainable waste management.

Water retention and heat storage characteristics of phase change hydrogel in cooling pavement

Phase change hydrogel (PCH) combines the heat storage characteristics of phase change material with the water retention capacity of hydrogel, showing great potential in cooling pavement applications. This study aims to investigate the water retention and heat storage properties of PCH in cooling pavement, providing new insights for mitigating the urban heat island effect. Based on the principle of osmotic pressure, polyethylene glycol (PEG) solution was actively absorbed by superabsorbent polymers (SAP) to form stable PCH. By infusing the asphalt mixture skeleton with PCH-containing phase change grouting material (PCGM), a temperature-regulating phase change grouting pavement (PCGP) can be obtained. Morphological characterization showed that PCH was uniformly distributed in PCGM and effectively locked PEG during high temperature and water absorption/release processes without leakage. PCH imparted excellent water retention properties to PCGM, with a saturation water absorption rate of 44.1 %, which is 6.2 times higher than the control group, and a water retention rate of 34.31 % after heating at 60 °C for 12 hours. Furthermore, PCGM exhibited considerable heat storage performance, with a melting enthalpy of 15.74 J/g and a crystallization enthalpy of 12.07 J/g. Based on these, PCGP demonstrated outstanding temperature-regulating ability, reducing surface temperatures by 9.3 °C and 11.6 °C under dry and saturated conditions, respectively, compared to control pavement. In conclusion, this study provides a theoretical basis for the development of novel cooling pavement materials and shows great potential for its wide application in urban infrastructure construction.

Factors Affecting the Physical Properties of Microbial Induced Calcium Carbonate Precipitation (MICP) Enhanced Recycled Aggregates

Microbial-induced calcium carbonate precipitation (MICP) can enhance the physical properties of recycled aggregates. Compared to traditional technologies, MICP offers environmental benefits and produces no pollution. However, its mineralization efficacy is significantly influenced by the process parameters. To investigate this, an MICP mineralization test was conducted by manipulating various process parameters throughout the mineralization process. The water absorption rate, apparent density, and calcium carbonate content of the mineralized recycled aggregates were assessed to discern the impact of these parameters on the mineralization outcome. Further analysis using techniques such as thermogravimetric analysis (TG), X-ray diffraction (XRD), nuclear magnetic resonance (NMR), and scanning electron microscopy (SEM) were employed to elucidate the mineralization mechanism of the recycled aggregates at a micro-level. The findings indicated that the MICP treatment induced bacteria to precipitate CaCO3, forming calcite crystalline CaCO3 within the pores and microcracks. This led to a denser interfacial transition zone and, consequently, improved the physical properties of the recycled aggregates. Optimal mineralization was achieved when the bacterial solution concentration was 1.4, the temperature and pH were 35 °C and 9, respectively, and the urea concentration, Ca+ concentration, and mineralization time were 0.5 mol/L, 0.5 mol/L, and 7 days, respectively. Under these conditions, the mineralized recycled aggregate exhibited a 16.07% reduction in water absorption, a 1.07% increase in apparent density, and a 2.28% change in mass.

Experimental and Statistical Analysis of Concrete Eco-Cobble Using Organic and Synthetic Fibers

The environmental impact of traditional construction materials necessitates the development of sustainable alternatives. This study evaluates eco-cobbles as novel building materials designed to reduce environmental footprint while maintaining performance standards. The objectives were to develop an eco-friendly cobble alternative and assess its effectiveness through laboratory tests. Eco-cobbles were synthesized using recycled and bio-based materials and tested for compressive strength, flexural strength, and water absorption at 14 and 28 days. The compressive strength ranged from 11.5 MPa to 26.8 MPa, with a maximum value observed at 28 days in a mixture containing 95% concrete and 5% polyethylene terephthalate (PET). Flexural strength varied from 9.1 MPa to 28.7 MPa, with the highest value achieved in a mixture of 95% concrete and 0% fibers. Water absorption rates ranged from 2.1% to 6.6%, demonstrating an effective balance between performance and durability. Environmental assessments indicated a 30% reduction in resource consumption and a 40% decrease in carbon footprint compared to traditional cobble production methods. The findings demonstrate that eco-cobbles not only meet performance standards but also offer significant environmental benefits with a 99% compliance from the results obtained by response surface methodology plots, confirming that eco-cobbles offer a viable, sustainable alternative to conventional materials, with the potential for broader application in eco-friendly construction practices.

Design and Coupled Moisture-Thermal Transfer Simulation of Opposite Cross-Section Polyethylene Terephthalate Knitted Fabric with Hygroscopic Quick-Drying Capability.

In addition to sportswear and outdoor equipment, moisture-absorbent quick-drying fabrics are also widely used in everyday clothing and home textiles. In this study, three types of weft-knitted fabrics were designed using Coolmax fiber and polypropylene fiber. The Coolmax/PP fabric exhibits good stretchability with a strain of 180.5% and achieves a high cumulative individual transfer capability of 691.6%, with a water absorption rate of 50.2%/s. The moisture conductivity gradient presented good moisture and heat conductivity in a simulated human body temperature environment using an infrared camera. Furthermore, mathematical modeling was constructed and visual simulation analysis was conducted to explore moisture-thermal transfer behavior. The simulation results closely align with experimental data, providing insights into designing flexible and wearable quick-drying fabrics for thermal management.