Search Results (152)

Ambient-temperature asphalt binders have emerged as a sustainable alternative to traditional hot-mix asphalt, offering significant advantages in energy conservation and emission reduction. This review systematically examines the research progress and development trends of high-performance reactive asphalt binders designed for ambient-temperature application, which achieve enhanced performance through chemical cross-linking reactions. The study focuses on three core material systems: epoxy resin, waterborne epoxy emulsified asphalt, and polyurethane. For each system, we comprehensively summarize the material composition, strength formation mechanisms, and mix design methodologies. Key evaluation methods for critical pavement performance—including strength characteristics, water stability, and high-temperature performance—are critically reviewed. Furthermore, microscopic characterization techniques including scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC) are discussed to elucidate the underlying mechanisms governing performance evolution. Analysis reveals that epoxy-based binders exhibit superior strength and stiffness, rendering them suitable for heavy-traffic pavements; waterborne epoxy emulsified asphalt binders combine environmental compatibility with construction convenience for thin-layer rehabilitation, while polyurethane-based binders demonstrate exceptional elasticity and rapid curing characteristics for quick-traffic-opening scenarios. Although current research has established a preliminary performance evaluation framework, the absence of unified technical standards constrains widespread engineering implementation. Future research priorities should focus on developing water-triggered curing systems, intelligent responsive materials, and comprehensive standardization systems to fully harness the engineering potential of these sustainable binders. Full article

To address the issues of poor sustained-release behavior and limited long-term efficacy associated with conventional salt-storage materials, this study developed the epoxy-resin-encapsulated slow-release salt-storage filler to enhance both the engineering performance and the deicing/snow-melting capacity of salt-storage pavements. In this study, attapulgite was optimized and selected as the salt storage carrier through the adoption of pesticide coating technology and experimental testing, wherein a deicing salt blend with a CaCl₂ to NaCl mass ratio of 2:1 was loaded via a wet adsorption method. Subsequently, using dimethicone as the surface modifier, the optimal encapsulation process was determined to involve the dilution ratio of epoxy resin to cyclohexanone of 4:1 and the curing agent dosage of 30% by weight. The results indicated that the recommended content of the filler should not exceed 5%. The filler reduced the high-temperature stability and water stability of the mixture, while the low-temperature crack resistance first increased and then decreased, peaking at the 2% filler content with an improvement of 12.2%. The water stability was the most significantly affected by the filler content. Ice–snow melting performance tests demonstrated that the salt-storage mixture with 5% filler achieved the deicing rate of 56.35% at −5 °C, meeting the industry standard requirements. The self-prepared slow-release salt-storage filler exhibited superior long-term ice–snow melting performance to V-260, with the slow-release duration extended by 60%. The salt release process was divided into three distinct stages: rapid dissolution, stable release and slow dissolution. The 60 °C was determined as the optimal temperature for the accelerated immersion testing, which the accelerated test could effectively simulate the natural immersion process. Based on the prediction model established accordingly, the functional service life of snow-melting for this slow-release salt-storage asphalt pavement in northern area was estimated be approximately 4.07 years. The slow-release salt-storage filler fabricated in this work possesses both remarkable sustained-release behavior and deicing efficacy. The findings provide the technical foundation for the development of novel salt-storage pavement materials, performance characterization, and mechanistic analysis of snow-ice melting. Full article

The anti-corrosion performance of epoxy coatings in saline solution environments is restricted by their surface hydrophilicity and microporous defects. Herein, we developed a modified epoxy (MEP)-based superhydrophobic anticorrosive coating by fluorinated resin matrix and incorporation of polyaniline@expanded graphite (FPANI@MEG) anticorrosive fillers. The FPANI@MEG fillers were fabricated via in situ polymerization of aniline on the surface of dopamine-modified expanded graphite to construct the micro-nano hierarchical structure required for superhydrophobicity, while providing barrier shielding and active passivation functions. The results showed that the final coating exhibited excellent superhydrophobicity with a water contact angle of 156.5 ± 1.8° and sliding angle of 3.0 ± 0.6°, along with excellent adhesion and adaptability to various complex environments. Meanwhile, the coating maintained superhydrophobicity after 400 cycles of Taber abrasion and 450 g of falling-sand impact, demonstrating hydrophobic robustness. Furthermore, the coating exhibited a low-frequency impedance modulus of 2.30 × 10⁷ Ω·cm² after immersion in NaCl solution for 15 days. The synergistic combination of air film shielding, physical barrier, and active passivation endowed the coating with good anticorrosion performance. This work may provide a theoretical reference for improving the corrosion protection of epoxy-based superhydrophobic coatings on carbon steel in aggressive saline solution environments. Full article

Hydraulic concrete suffers severe damage from high-velocity sand-bearing water flow. Traditional single-layer coating materials struggle to simultaneously satisfy the requirements of strong adhesion, high abrasion resistance, and long-term durability. In this study, a functionally graded multilayer composite coating system, designated HIR (Hybrid Epoxy–Interfacial Primer–Rubber), was developed. The HIR system comprises a hybrid acrylic–epoxy resin (HEP) top layer, a modified epoxy-based interfacial primer (EIP), and a sprayed liquid rubber (SLR) middle layer, realizing synergistic enhancement of interfacial bonding, deformation adaptability, and abrasion resistance. The results showed that the HIR achieved an adhesion strength exceeding 2.0 MPa to concrete. The HEP exhibited an elongation at break exceeding 30%, while the SLR showed an elongation at break higher than 1000%. The anti-abrasion strength of the HIR-coated concrete reached 254.35 h/(kg/m²), which is 15 times that of uncoated concrete. Moreover, the coated concrete maintained a relative dynamic elastic modulus above 95% after 300 freeze–thaw cycles. DMA revealed multiple glass transition temperatures in both SLR (24 °C, 101 °C, 137 °C) and HEP (62 °C), enabling effective energy dissipation over a wide temperature range. Through interlayer property matching and synergistic enhancement, the HIR significantly enhances both abrasion resistance and freeze–thaw durability of hydraulic concrete. Full article

We co-modified layered double hydroxide (LDH) in water using phosphocreatine (PC) and dodecylphosphoric acid (DPA) to obtain a highly dispersible LDH. Embedding this LDH in epoxy enabled V-0 at 7 wt% and lowered HRR, THR and TSP, attributed to a dense char and PC-DPA synergy. SEM, WAXS, and TGA characterised the structure and thermal behaviour of the functionalised LDHs. These modified LDHs were then loaded into the epoxy resin (EP) to develop flame-retardant nanocomposites. Compared to unmodified LDH (NO₃-LDH) and PC-modified LDH (PC-LDH), PC-DPA-LDH showed superior dispersion and compatibility within the epoxy matrix. As a result, PC-DPA-LDH/EP achieved a UL-94 V-0 rating at only 7 wt% loading, while NO₃-LDH/EP had no rating, and PC-LDH/EP reached only V-2. Moreover, PC-DPA-LDH/EP demonstrated significant decreases in peak heat release rate (46.4%), total heat release (34.5%), and total smoke production (59.7%) compared with neat EP. These improvements were attributed to the synergistic flame-retardant effects of PC and DPA, as well as to the formation of a compact char layer that effectively insulated the underlying material and suppressed volatile emissions. This work highlights the potential of bio-based, aqueous-synthesised nanohybrids for high-efficiency, eco-friendly flame-retardant epoxy systems. Full article

This study introduces advanced epoxy formulations incorporating carbon-based nanofillers, carbon nanotubes, nanofibers, and functionalized graphene. The epoxy matrix was optimized to lower moisture absorption and enhance multifunctional properties. A non-stoichiometric epoxy/hardener ratio reduced equilibrium water concentration (C_eq) by up to 30% compared to unmodified epoxy, achieved by minimizing polar groups responsible for water bonding. These improvements benefit the aerospace, marine, and wind energy sectors. All nanofillers form a secondary phase with reduced glass transition temperature (T_g), but functionalized graphene performs best. Its self-assembled sheet architectures trap resin, limit water interaction, and create conductive pathways, improving strength, reducing moisture uptake, and achieving a low electrical percolation threshold (EPT). Full article

To overcome polymer-based plugging materials’ disadvantage of being prone to degradation and failure under hydrothermal conditions, an epoxy resin plugging particle with a high-pressure-bearing capacity under high temperatures was prepared by optimizing the curing process. Bisphenol A Epoxy Resin E51 and Diethyltoluenediamine (DETDA) were selected as raw materials for sample preparation. Due to the high viscosity of the system, 1,2-cyclohexanediol diglycidyl ether was introduced as a diluent, and an optimal concentration of 20% was determined through experimental optimization. Non-isothermal differential scanning calorimetry, bottle testing, and infrared spectroscopy were employed to investigate the variation laws of curing temperature, curing time and curing degree during the epoxy resin curing process via one-step and multi-step methods. The compressive strength of the epoxy resin prepared using the two processes was evaluated. After comprehensively comparing the preparation time, process complexity, and compressive strength of the final samples of the one-step and two-step curing methods, the one-step process (90 °C/5 h) was determined to be superior. In addition, the results of the fracture plugging experiment showed that after the bulk epoxy resin prepared using the optimized process was made into particles through a mechanical method and treated under hydrothermal conditions at 120 °C, the maximum breakthrough pressure reached 4.2 MPa, which was 950% and 135.96% higher than that of Particle 1 (Poly(2-acrylamido-2-methylpropanesulfonic acid)/acrylamide (PAMPS/AM) gel) and Particle 2 (PAMPS/AM gel treated with Polyethylene glycol (PEG)), respectively, which were used as control groups. This result indicates that epoxy resin can be used as a high-temperature-resistant plugging material and should be further researched. Full article

Objectives: To evaluate the physicochemical properties of a novel strontium silicate-based root canal sealer (C-Root SP) in comparison with a calcium silicate-based sealer (TotalFill BC) and an epoxy resin-based sealer (AH Plus). Methods: Setting time, net mass change (apparent solubility behavior), pH changes, and surface characteristics were assessed based on ISO 6876 and ANSI/ADA Specification No. 57, with minor methodological modifications. Net mass change and pH were evaluated over 28 days. Surface morphology and elemental composition were analyzed after dry and aqueous aging in deionized water using scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy. Data were analyzed using one-way and repeated-measures ANOVA with Tukey’s post hoc test (α = 0.05). Results: AH Plus exhibited the longest initial and final setting times (10.93 ± 0.65 h and 37.33 ± 0.13 h), whereas TotalFill BC showed the shortest (7.98 ± 0.32 h and 30.18 ± 0.20 h); C-Root SP demonstrated intermediate values (9.35 ± 0.38 h and 32.75 ± 0.57 h) (p < 0.001). C-Root SP exhibited positive net mass change values (indicative of net mass loss), ranging from 5.32 ± 4.72% at 24 h to 6.83 ± 5.55% at 28 days, significantly higher than AH Plus and TotalFill BC (p < 0.001), which showed negative values indicative of apparent mass gain. All sealers demonstrated alkaline conditions, with C-Root SP maintaining the highest apparent pH values throughout the evaluation period (p < 0.001). Surface and compositional changes were observed in the bioceramic sealers following aqueous aging, with increased detectable strontium content in C-Root SP. Conclusions: C-Root SP exhibited physicochemical behavior consistent with a strontium-modified calcium silicate-based sealer, characterized by hydration-driven hydroxyl ion release resulting in apparent alkalinity and ion exchange-associated behavior, and dynamic surface changes consistent with those reported for bioceramic materials. Clinical Significance: Strontium incorporation may influence hydration-mediated physicochemical behavior; however, further in vitro and in vivo studies are required to determine its clinical relevance. Full article

Background/Objectives: Residual EDTA may persist after smear-layer removal and after the application of contact sealers during setting. This in vitro study compared the effect of 1 min of pre-setting surface contact with 17% EDTA (vs. distilled water) on a calcium silicate-based sealer (AH Plus Bioceramic Sealer) and an epoxy resin-based sealer (AH Plus). Methods: Discs were prepared (N = 108) in a 2 × 2 design (n = 27/group); per group; n = 12 were used for solubility followed by eluate pH using the same specimens/eluates after 24 h immersion in distilled water; n = 12 were used to test Vickers microhardness on an independent set after setting; and n = 3 were used for SEM/EDS. Results: Data were analyzed at α = 0.05 using Kruskal–Wallis tests followed by Bonferroni-adjusted pairwise Mann–Whitney U tests for solubility and eluate pH, and one-way ANOVA was performed followed by Tukey’s post hoc test to assess the microhardness. Solubility differed among groups (p < 0.001) and was higher for the bioceramic sealer than for the resin sealer; pre-setting EDTA exposure increased solubility for the AH Plus Bioceramic Sealer (0.86 ± 0.08% to 1.30 ± 0.16%) and decreased solubility for AH Plus (0.34 ± 0.04% to 0.22 ± 0.03%) (p < 0.05). The eluate pH also differed among groups (p = 0.001) and was higher for the bioceramic sealer (≈11.7) than for the resin sealer (≈8.7–9.3), with no within-material differences (p = 0.999 and p = 0.851). Microhardness differed among groups (p < 0.001) and was higher for AH Plus (239.70–246.92 HV) than for AH Plus Bioceramic (131.72–170.83 HV); EDTA reduced microhardness only for the bioceramic sealer (p < 0.001), with no significant change for AH Plus (p = 0.475). Descriptive SEM/EDS findings suggested increased surface irregularities and lower surface Ca for AH Plus Bioceramic after EDTA exposure (12.68 to 7.31 wt%). Conclusions: Pre-setting EDTA contact therefore produced material-dependent changes in early properties and adverse surface-related effects in the calcium silicate-based sealer, supporting thorough chelator removal before obturation. Full article

This study investigates the utilization of Abies alba exudate resin for the development of hybrid resins intended as matrices for composite materials. The novelty of this work lies in demonstrating that physically hybridized, bio-derived resin systems based on Abies alba exudate can exhibit distinct mechanical and dynamic behaviors solely by adjusting the solvent-assisted formulation route, without intentional chemical modification and without spectroscopic evidence of co-network formation within the limits of ATR-FTIR analysis, although limited interfacial interactions cannot be excluded. Two formulation routes were explored: (i) dilution of Abies alba exudate in turpentine derived from pine buds, (ii) dilution in ethanol (96%). The diluted resins were subsequently blended with a commercial epoxy system, which was cured with its amine hardener to form solid matrices in which the Abies alba component was physically incorporated. The resulting hybrid resins were characterized by multiple testing methods and further applied in the fabrication of cotton fiber-reinforced composites. The turpentine-based hybrid resin (HR1) showed a rigid mechanical response, with tensile strengths of approximately 13.2–13.5 MPa, compressive strengths of about 30 MPa, Shore D hardness values of 56–58.5, and a low damping ratio (≈0.026). In contrast, the ethanol-based hybrid resin (HR2) exhibited a highly deformable mechanical response, characterized by low tensile strength (≈0.5 MPa), very high elastic recovery, low hardness (<10 Shore D), and a significantly higher damping ratio (≈0.139). To demonstrate their applicability in composite manufacturing, the HR1 matrix was reinforced with cotton fabric, leading to a substantial improvement in tensile strength (25–26 MPa) and flexural strength (35–36 MPa), together with an increased natural frequency. Water absorption tests revealed limited moisture uptake for the neat hybrid resins (≤0.04 g), while the cotton-reinforced composite exhibited higher but largely reversible water absorption (≈21.5%), associated with the hydrophilic nature of the reinforcement. Full article

Natural fibre-reinforced composites (NFCs) have attracted attention as sustainable alternatives to synthetic fibre composites. However, their hydrophilic nature and susceptibility to moisture absorption, especially in combination with process-related defects, can compromise long-term performance. This study critically examines the effects of hydrophobic fumed silica, incorporated into an epoxy matrix, on the processing, moisture uptake, and mechanical properties of flax/epoxy laminates produced via resin transfer moulding (RTM). Epoxy systems containing 0–5 wt% silica were characterised in terms of particle dispersion, rheological properties, thermal behaviour, and water absorption. Corresponding laminates were analysed for void content, Fickian diffusion behaviour, and tensile performance in dry and saturated states. Despite its hydrophobic surface treatment, silica increased resin water uptake and, at 5 wt%, led to a substantial rise in viscosity, poor fibre impregnation, and increased porosity. The resulting laminates exhibited faster and higher moisture uptake and significantly reduced wet mechanical properties, especially for highly filled systems. While thermal stability improved slightly, the overall findings revealed that the chosen silica-based matrix modification led to clear trade-offs and processing limitations under RTM conditions. This study highlights the importance of assessing such limitations early in the design process and demonstrates that the selected silica type is not a viable strategy for improving moisture resistance in NFCs. Full article

Sulfate corrosion is a significant durability issue for concrete used in sewage and hydraulic infrastructure. In sulfate-rich environments, the formation of expansive products (e.g., ettringite and thaumasite) leads to a progressive loss of performance. Unlike conventional protection methods, which rely on surface-applied coatings or impregnation, this study examines the use of water-dilutable epoxy resins as an internal, volume-wide admixture dispersed throughout the concrete matrix to provide whole-body protection. The experimental program evaluated the mechanical performance, microstructure, and sulfate ion ingress/penetration dynamics of resin-modified concretes. The results suggest that using the appropriate amount of resin can limit the penetration of aggressive ions and slow the harmful changes associated with sulfate attack while maintaining the material’s overall performance. Overall, these findings suggest that water-based epoxy admixtures are a promising strategy for improving the durability of concrete in sulfate-exposed environments. They also provide guidance for designing more resistant cementitious materials for modern infrastructure applications. Full article

Adsorption chillers can produce chilled and desalinated water using low-grade heat, but their performance is limited by low coefficient of performance (COP) and large system mass. Enhancing heat and mass transfer in the sorbent bed is key to improving efficiency. This work introduces and systematically evaluates binder-stabilized silica gel composites as a structural and thermal enhancement strategy for adsorption chillers. Silica gel composites bonded with epoxy resin and polyvinyl alcohol (PVA) were evaluated for adsorption chiller applications. Thermal stability, conductivity, microstructure, equilibrium sorption, and sorption hysteresis were assessed. The results indicate that PVA-based composites were thermally unstable and discarded, whereas epoxy-bonded silica gel showed high thermal stability and mechanically robust granules with preserved pore connectivity. The epoxy composite exhibited 109% higher thermal conductivity than loose silica gel, improving internal heat transfer. This improvement is accompanied by a reduction in sorption capacity of approximately 58%, attributable to the inert resin fraction. Notably, the composite exhibits a reduced and locally negative sorption hysteresis, indicating facilitated desorption and lowered internal diffusion resistance. The epoxy-bonded silica gel therefore provides a promising combination of thermal stability, improved heat transfer, and enhanced sorption–desorption behaviour, supporting its potential to increase the efficiency of next-generation adsorption chillers. Full article

Developing sustainable, high-performance biomass composites is crucial for replacing non-renewable structural materials. In this study, a “bamboo steel” composite was fabricated using a multilevel modification strategy involving alkali pretreatment, toughened resin impregnation, and surface functionalization. Bamboo fibers were treated to remove hemicellulose and lignin, enhancing porosity and interfacial bonding. The bamboo scaffold was subsequently impregnated with a thermo-plastic polyurethane-modified epoxy resin to create a robust, interpenetrating network. The optimized composite (treated at 80 °C) exhibited a flexural strength of 443.97 MPa and a tensile strength of 324.14 MPa, demonstrating exceptional stiffness and toughness. Furthermore, a superhydrophobic coating incorporating silica nanoparticles was applied, achieving a water contact angle exceeding 150° and excellent self-cleaning properties. This work presents a scalable strategy for producing bio-based structural materials that balance mechanical strength with environmental durability. Full article

An epoxy resin can be crosslinked with an imidazole-based ionic liquid (IL), whose excess, provided its high melting temperature, can potentially form a dispersed phase to store thermal energy and produce a phase-change material (PCM). This work investigates the crosslinking of diglycidyl ether of bisphenol A (DGEBA) using 1-ethyl-3-methylimidazolium chloride ([EMIM]Cl) at its mass fractions of 5, 10, 20, 40, and 60%. The effect of [EMIM]Cl on the viscosity, curing rate, and curing degree was studied, and the thermophysical properties and morphology of the resulting crosslinked epoxy polymer were investigated. During the curing, [EMIM]Cl changes its role from a crosslinking agent (an initiator of homopolymerization) and a diluent of the epoxy resin to a plasticizer of the cured epoxy polymer and a dispersed phase-change agent. An increase in the [EMIM]Cl content accelerates the curing firstly because of the growth in the number of reaction centers, and then the curing slows down because of the action of the IL as a diluent, which reduces the concentration of reacting substances. In addition, a rise in the proportion of [EMIM]Cl led to the predominance of the initiation over the chain growth, causing the formation of short non-crosslinked molecules. The IL content of 5% allowed for curing the epoxy resin and elevating the stiffness of the crosslinked product by almost 7 times compared to tetraethylenetriamine as a usual aliphatic amine hardener (6.95 GPa versus 1.1 GPa). The [EMIM]Cl content of 20–40% resulted in a thermoplastic epoxy polymer capable of flowing and molding at elevated temperatures. The formation of IL emulsion in the epoxy matrix occurred at 60% [EMIM]Cl, but its hygroscopicity and absorption of water from surrounding air reduced the crystallinity of dispersed [EMIM]Cl, not allowing for an effective phase-change material to be obtained. Full article