• First study on flexural and fracture behavior of DβS-based geopolymer concrete. • 25–50% DβS improves modulus of rupture, fracture toughness, and ductility. • Peak CMOD and post-cracking behavior enhanced, reducing brittleness. • Life cycle assessment shows 72% lower global warming potential vs cement concrete. • DβS valorizes lithium waste, enabling sustainable low-carbon construction. Geopolymer concretes offer substantial environmental benefits, along with notable durability and mechanical advantages, relative to traditional cement concrete. However, geopolymer concretes exhibit relatively brittle fracture behavior and limited flexural performance when cured at ambient temperature. For the first time, this research evaluates flexural properties of ambient-cured geopolymer concrete prepared with delithiated β -spodumene (D β S), a lithium refinery residue. Four unique mixes were formulated by partial or full substitution of fly ash (FA) with D β S at 0% (control), 25%, 50%, and 75% of the total binder. Mechanical properties, including compressive and splitting tensile strengths, and fracture-related parameters of load-bearing capacity, crack mouth opening displacement (CMOD), modulus of rupture, fracture energy, fracture toughness and ductility index, were systematically evaluated. Results indicate that a partial replacement of FA with D β S (25–50%) significantly enhances the mechanical performances. Although the best results are obtained at 25% replacement, at 50% D β S replacement, the 28-day compressive and splitting tensile strengths increase by 10% and 8%, respectively, relative to the control concrete. Load-bearing capacity and peak CMOD improve by about 4%, while modulus of rupture, fracture toughness, and fracture energy increase by 4%, 33%, and 2%, respectively. The ductility index increases substantially at full FA replacement, reaching up to 2.2 times that of the control concrete. A life cycle assessment further confirms that increasing D β S content in geopolymer concrete substantially reduces environmental impacts, with the greatest benefits observed at 50% substitution. Overall, the findings demonstrate that D β S not only improves the mechanical characteristics of geopolymer concrete but also significantly enhances its flexural behavior and fracture resistance. This improvement is critical for the construction sector, as flexural performance governs crack resistance and ensures structural integrity of elements under bending stresses.

• Milled zirconia shows higher flexural strength than 3D-printed overall • Printed 3Y/5Y multilayer zirconia matches flexural strength of milled 3Y/5Y • Printed 5Y zirconia matches the flexural strength of milled 5Y zirconia • Milled zirconia has higher Weibull modulus and fewer defects than printed • Monoclinic phase occurs in 3Y regions; cubic phase only in milled 5Y

Influence of alkaline treatment on banana peel powder functionality at ultra-low loading in PLA composites: A comparative study

Vinyl ester resins (VERs) are widely used in various industries owing to their excellent mechanical properties and chemical resistance. However, their inherent flammability severely restricts further application, and conventional flame retardants often enhance fire safety at the cost of mechanical and thermal performance. Herein, a reactive ammonium polyphosphate (APP) derivative (MDO) with abundant C=C bonds was synthesized by grafting maleic anhydride onto the surface of an amine-modified APP (DO). The resulting MDO not only acts as an efficient flame retardant but also participates in the curing of VER through radical copolymerization. With the addition of only 22 wt% MDO, the 22% MDO/VER composite achieves a vertical burning (UL-94) V-0 rating and a high limiting oxygen index (LOI) of 28.5%, accompanied by remarkable reductions in peak heat release rate (PHRR), total heat release (THR), peak smoke production rate (PSPR) and total smoke production (TSP) compared to the neat VER. More importantly, introducing MDO enhances the tensile strength (49% improvement), flexural strength (56% improvement), and impact strength (19% improvement) of VER while effectively maintaining the glass transition temperature ( T g , 115 °C). The dual enhancement originates from the reactive crosslink sites of MDO that improve the interfacial compatibility and promote condensed-phase charring. This work provides a rational strategy to fabricate high-performance VER composites with superior fire retardancy, outstanding mechanical properties and well-preserved thermal performance.

This study aims to elucidate the influence mechanisms of carbon nanotubes (CNTs) on asphalt binder and mixture performance through multiscale experimental characterization. Dynamic shear rheometry (DSR), multistress creep recovery (MSCR), single-edge notched beam (SENB) fracture testing, and atomic force microscopy (AFM) were employed to quantitatively correlate CNT concentrations with enhanced rheological properties and creep resistance. The recommended CNT dosage was determined based on homogeneous dispersion, performance improvement, and cost-effectiveness analysis. Subsequent evaluations focused on the high- and low-temperature stability, viscoelastic behavior, and fatigue resistance of CNT-modified asphalt mixtures at the identified recommended dosage. The results demonstrated the following: Microstructural analysis showed that CNT-induced wax crystallization and chemical interaction reorganized the colloidal structure of the asphalt. A 1.0% CNT dosage was identified as the recommended value to achieve uniform dispersion, performance gain, and cost-effectiveness. Validation tests on the mixture showed a 27% reduction in rutting depth, a 9.9% to 45.1% increase in dynamic modulus, and a 28% increase in flexural strength, confirming the cross-scale synergies from nanomodification to macroscopic performance. This research establishes a theoretical-experimental framework for designing nanoengineered asphalt materials, offering a viable solution for durable pavement infrastructure under extreme environmental and mechanical stress conditions.

The growing demand for sustainable construction materials has led to increased research on alternative binders that reduce environmental impact. This study investigates the development and performance of one-part alkali-activated concrete (OPAA) incorporating pulverized rice husk ash (PRHA), ground granulated blast furnace slag (GGBFS), and high-chloride contaminated recycled coarse and fine aggregates (RCA, RFA). Using anhydrous sodium metasilicate (ASMS) as the activator, the research focuses on optimizing mechanical and durability properties through statistical analysis of variance (ANOVA). Experimental results demonstrate compressive strengths ranging from 52 to 67 MPa, flexural strengths between 4.13 and 5.25 MPa, and split tensile strengths of 3.19 MPa. The modulus of elasticity (MOE) achieved values between 30.91 and 31.83 GPa, with water absorption rates varying from 0.57% to 2.97%. Durability assessments, including sorptivity, high-temperature resistance, and microstructural analysis using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD), confirmed the formation of dense C─ A─ S─ H and N─ A─ S─ H gels, contributing to enhanced mechanical strength and durability. Additionally, thermal stability tests demonstrated that OPAA concrete retains significant compressive strength even after exposure to 600°C, making it suitable for fire-resistant applications. Overall, this study provides a scalable and sustainable solution for reducing the carbon footprint of the construction industry while enhancing material performance. The findings support the adoption of alkali-activated concrete as a viable alternative to ordinary portland cement (OPC)-based concrete, contributing to the advancement of green building practices and sustainable infrastructure development. From a sustainability perspective, the study highlights the significant reduction in embodied energy (EE) and embodied carbon dioxide emissions (ECO2e) compared to OPC.

Aim: With the aim to improve the thermal and mechanical characteristics of nanocomposites for cutting-edge engineering applications, this work looks at how nanotubes and nanodiamonds can be integrated into 3D printing processes. Background: The performance of 3D-printed products has been greatly enhanced by the addition of nanomaterials like carbon nanotubes (Carbon nanotubes) as well as nanodiamonds into polymer matrices. While nanodiamonds offer remarkable hardness and thermal stability, carbon nanotubes are widely recognized for their better electrical conductivity and bending strength. Their qualities make them the best options for raising the calibre of nanocomposites that are 3D printed. Objective: This paper looks at the effects of dispersion, functionalization, and synthesis of nanotubes and nanodiamonds on the mechanical and thermal properties of nanocomposites, taking into account the environmental impact, obstacles, and applications of these materials. Method: The techniques for adding nanotubes and nanodiamonds to 3D printing formulations were the main topic of a thorough literature study. A number of important factors were examined, including stability, toughness, elasticity, and tensile strength. The influence of uniform particle spread on overall composite performance as well as developments in dispersion technologies were reviewed in the paper. Results: The study found that the incorporation of nanotubes and nanodiamonds into 3D printing processes significantly improved the mechanical and biological properties of nanocomposites. These nanomaterials improved electrical conductivity and thermal stability, making them suitable for applications in electronics, aerospace, and biomedical fields. However, challenges such as high costs, ecological impacts, and long-term stability assessments remain. Conclusion: Although there is potential for next-generation materials with the incorporation of nanotubes along with nanodiamonds in 3D-printed nanocomposites, issues such as uniform nanoparticle dispersion still need to be resolved.

Structure property correlations of vacuum assisted squeeze cast AA5085-SiC-Si3N4 hybrid composites

This research examines the progression of mechanical properties in nanoconcrete under various high-temperature curing conditions. The compressive, flexural, and split tensile strength of plain concrete (PC), nano-SiO2 concrete (NSC), and nano-CaCO3 concrete (NCC) were examined under standard curing (SC), steam curing (StC), and hot water curing (HWC). The strength development mechanism of nanoconcrete under different curing methods was revealed using X-ray diffraction. The findings indicate that the optimal content of nano-SiO2 and nano-CaCO3 in concrete under the three curing methods is 2% and 1%, respectively. Nano-SiO2 contributes more significantly to the concrete’s mechanical properties than nano-CaCO3. HWC and StC greatly enhanced the concrete’s early mechanical properties, but high-temperature curing resulted in varying degrees of degradation in the later concrete’s mechanical properties, and HWC was more effective than StC. Nanoparticles can combine with high-temperature curing to impart higher concrete’s early mechanical properties while mitigating the decline of its later mechanical properties. The 56-day compressive strength of HWC-NSC20 and HWC-NCC10 could be restored to 107.28% and 103.54% of SC-PC, respectively, with nano-SiO2 showing a more significant repair effect. Both high-temperature curing and nanoparticles enhanced the hydration degree of C2S/C3S phases at 3 days. Delayed ettringite formation and incomplete cement hydration are the primary causes of the loss of later mechanical properties in hot water–cured concrete. The incorporation of nanoparticles partially repaired the degradation of later mechanical properties caused by high-temperature curing.

Mechanical properties and wear behavior of Ti3SiC2–TiB2 composites obtained by reaction spark plasma sintering

Controlling light absorption in digital light processing (DLP) via pigment incorporation offers a versatile approach to tuning curing dynamics, shrinkage behaviour, and mechanical performance in ceramic additive manufacturing. In this study, black pigment (BP) was systematically introduced into a silica-based photopolymer suspension to modulate optical attenuation and enhance the geometric fidelity, surface quality, and dimensional accuracy of printed parts. An optimal 2 wt% BP formulation reduced peeling forces by ≈40% and eliminated recoating resistance, enabling smoother layer separation and improved print stability. Cure uniformity was enhanced, suppressing overcuring artefacts and sharpening lateral features. The degree of polymer conversion increased from ≈50% (no pigment) to ≈76%, correlating with reduced early-stage mass loss during thermogravimetric analysis, indicating a more complete crosslinked network and reduced low-temperature volatilization. These effects led to significantly improved mechanical performance, with green strength reaching ≈36 MPa and sintered strength ≈12 MPa, alongside minimized shrinkage anisotropy (ΔZ–XY ≈ 0.12%). Microstructural and profilometric analyses confirmed improved microstructural integrity and surface quality, with lateral surface roughness reduced to ≈4 μm and cure-induced overgrowth eliminated. Cure depth tuning effectively confined light penetration, improving interlayer bonding and dimensional precision. A full-scale silica-based ceramic core printed with the optimized formulation preserved intricate features and achieved dimensional accuracy within ±0.5 mm after sintering. These findings demonstrate that, within the studied silica-based system, pigment-modified photopolymer formulations enable high-resolution, low-defect DLP ceramic printing, offering a scalable and reliable route for precision components in aerospace, investment casting, and high-temperature tooling. • Black pigment tuned light absorption in DLP ceramic printing, improving cure uniformity and resolution. • At 2 wt.% BP, peeling force dropped ~40%, recoating became resistance-free, and conversion rose to ~76%. • Green and sintered flexural strengths reached ~36 and ~12 MPa, respectively. • Porosity decreased, surface roughness reached ~4 µm Sa, and shrinkage anisotropy was reduced to ~0.12%. • A full-scale silica-based core achieved ±0.5 mm post-sintering accuracy in complex geometries.

How durable are 3D-printed dental resin-based composites? An umbrella review.

Stereolithographic fabrication of gyroid-structured β-tricalcium phosphate scaffolds from solvent-based slurries

Tannin-phenolic hybrid biomacromolecular resins for extrusion-based biocomposite manufacturing.

Strengthening and toughening mechanisms of gradient Ti(C,N)-based cermets

This study analyzes the influence of porosity on Nextel TM 610/Al 2 O 3 -ZrO 2 short-fiber-reinforced composites for the first time. Its goal was the comparison of a short-fiber-reinforced all-oxide ceramic matrix composite (SF-Ox/Ox) with a fabric-reinforced material. Since the matrix system and the processing were the same for both materials, differences can be related to the use of short-fibers instead of fabrics. Zirconium-n-butoxide was infiltrated to decrease the porosity from 32% to 46%, which increased the bending strength and the Young’s modulus from 85±19 MPa to 120±23 MPa and 40±10 GPa to 82±12 GPa, respectively. The strain decreased with decreasing porosity from 0.25±0.05% to 0.16±0.03%. The damage-tolerant behavior was maintained for all samples, which was never shown for SF-Ox/Ox in such a porosity range. The less anisotropic alignment of the short-fibers is therefore advantageous for crack-deflection. This offers the possibility to obtain damage-tolerance while having a denser matrix system.

Development of woven-carbon-fabric-based composite structural batteries with quasi-solid electrolyte

Cold-formed steel lightweight concrete (CFS-LWC) composite beams: New design proposal

This study presents the design, fabrication, and mechanical performance of carbon fiber-reinforced polylactic acid (CF-PLA) bone plates incorporating auxetic and non-auxetic metamaterial architectures. Four lattice-structured bone plates (re-entrant, rotating square, tetrachiral, and hexagonal) were evaluated for their flexural, tensile, and compressive properties. The specimens were fabricated using Fused Deposition Modelling (FDM). The tetrachiral structure demonstrated superior bending capacity, achieving a flexural stress of 17MPa and a modulus of 1214MPa. Under both tension and compression, it exhibited the highest strength (24.5MPa and 40MPa, respectively) and stiffness (1441MPa in tension and 2352MPa in compression), while the rotating square designs offered a favorable balance of flexibility and strength. CF-PLA metamaterial bone plates showed substantially lower stiffness compared to various metallic plates (e.g., Titanium (Ti), steel) indicating their potential to reduce stress shielding and promote bone healing. The auxetic geometries, particularly the tetrachiral and rotating square, exhibited superior tensile and compressive behavior compared to the non-auxetic hexagonal bone plates. The results underscore the potential of 3D-printed CF-PLA metamaterial structures as effective alternatives to metallic bone plates. With further optimization, such designs could enable patient-specific implants with improved biomechanical compatibility and healing outcomes.

We explored the microwave drying of rubber tree (Hevea brasiliensis) wood using a multifaceted approach that encompasses various aspects. The primary objective was to examine drying behavior, drying time, moisture distribution across the core and surface, and to evaluate drying stresses via the prong test. Static bending and compression parallel to the grain were tested to assess the impact of microwave treatments on mechanical properties. The drying process showed a nearly uniform moisture distribution within the wood’s core and on its surface, indicating well-controlled drying. Most notably, the dried wood had no observable drying-induced stresses, suggesting a promising application of microwave drying. However, the volumetric shrinkage (%) was higher in microwave-dried samples (5.65% and 6.51%) than in air-dried samples (4.16%). A reduction in modulus of elasticity (MOE), modulus of rupture (MOR), and maximum compressive strength (MCS) was observed in the microwave-dried wood. Compared to the air-dried samples, the maximum reductions recorded were 15% for MOE, 18% for MOR, and 15% for MCS. The examination under light microscopy showed that the wood microstructures, such as ray cells and vessel walls, had incurred damage. The diminished mechanical properties could likely be linked to these micro-cracks or damage in the microstructures. The results show that these microstructural changes may significantly increase wood’s permeability. We also attempted to calculate the energy consumption for different microwave treatments. These findings emphasize the need for a balanced approach to optimizing microwave drying methods to mitigate reductions in mechanical properties while capitalizing on the advantages of reduced drying time and controlled, uniform moisture distribution.