Bond Strength Research Articles

Numerical Analysis of the Bond Behaviour of High-Strength Concrete-Filled Steel Square Columns with Different Shear Connectors

This paper deals with a numerical method of analysis of the performance of shear connectors in transferring load in high-strength concrete-filled steel tube square sections. The novelty of the model is that it considers all the important parameters that affect performance at once: bond strength, the transfer rate of each connector, and the stress distribution and deformation of each element. Four specimens fabricated using different types of connectors were validated using ABAQUS version 2017 software. The deformation of the connectors, concrete damage, and the local instability of the steel tube were extensively investigated. The main parameters considered were the ultimate bond strength and load transfer ratio. The shear connector arrangement consisting of four specimens, namely C1 with 16 studs, a circular rib (C2), a circular rib with 8 studs (C3), and a circular rib with 8 vertical ribs (C4), had a significant influence on the key parameters. Connectors C2, C3, and C4 transferred more than 80% of the total load. The circular rib was more effective in transferring the load and limiting slip than the vertical rib and the studs. The circular rib (C2) transferred the load mainly through the four corners. The deterioration of the concrete and local instability of the steel tube had complex deformations which were influenced by the geometry of the inserted connectors.

Green transforming black liquors as a new HCHO scavenger in production eco urea formaldehyde-agro composites

Innovative formaldehyde (HCHO)-scavenger based on black liquor is being developed to achieve eco-friendly low toxic urea formaldehyde (UF) adhesive. This scavenger will enhance the UF adhesive in production of agro-composites, complying with the environmental requirements. The HCHO-scavenger is synthesized from black liquor-based aerogels of various types of black liquors. The performance of the prepared scavengers is assessed via adsorption of HCHO; as well as its beneficial effect on properties of UF adhesive and UF-Palm fiber-composite. In order to produce a composite with mechanical properties and free-HCHO compliance with the standard specifications, the UF-scavenger system is optimized from its behavior. The data evidence the effective behavior of all investigated scavenger to improve bond strength of UF adhesive system (from 8.4 MPa to ∼ 18 MPa); and properties of UF-palm-composites, where the enhancement in modulus of rupture (MOR) and internal bond strength (IB), water repellent, reach to 50 %, 83 % and 7.7 %, respectively. In addition to success in producing eco-composites through reducing the free-HCHO of wood sample from 30.77 to 3.0–12.7 mg/100g with reduction percentages (58.7–90.3 %) exceeded those reported in the literature when carbon and silicon scavengers were used.

Influence of fatty acid composition on contact angle and wear rate of Jatropha curcas and sunflower’s mixture by varying compositions mixture

United Nation Sustainable Development Goals make sustainability become common goals which drives into investments of innovative product and technology focusing on sustainability. Cutting oils are generally made from mineral oil and the renewable replacement is sought after and one of them are Jatropha curcas and sunflower oil or blend of them. Viscosity and adsorption will influence the properties of cutting oil. The study concern on the relationship between percentage of JCO in the mixture to anti-wear properties and contact angle measured using goniometer contact angle and pin-on-disk tribometer by varying percentage of Jatropha curcas oil in mixtures for 2.5 %, 5 %, 10 %, 20 %, and 30 %. Also, molecular simulation is conducted through molecular dynamic in search of dipole moment, electrostatic potential, polarizability and bond energy. The approach is employed to connect molecular interaction and non-linearity trending of experiment. The experiment shows contact angle and wear scar width and also wear rate become higher when percentage of Jatropha curcas oil is higher. The lowest contact angle is 26.9 deg. and the highest is 36.9 deg. of 2.5 % and 30 % Jatropha oil. The highest wear rate is 6.77e-7 and the lowest is 2.74e-7 of 2.5 % and 30 % Jatropha oil. The simulation gives supporting basis in the finding of experiment in which the viscosity is more prominent in governing wear rate than adsorption. Increases of Jatropha curcas percentages have inversely proportional to dipole moment, polarizability, electrostatic potential and bonding which explain why the fatty acids become more adhere to the fatty acid than to surface. The finding is restricted only for idealized conditions both of molecular structure and surface.

The Fate of the Formic Acid Proton on the Anatase TiO2(101) Surface

AbstractAs a prototype adsorption reaction of gas Brønsted acid on oxides, we study the adsorption of formic acid on anatase. We perform infrared spectroscopy measurements of adsorbed HCOOH and HCOOD on TiO2 nanopowders, from 13 K up to room temperature in an ultra‐high vacuum chamber. We assign the IR signals via computed spectra from nuclear quantum dynamics simulations using our divide‐and‐conquer semiclassical ab initio molecular dynamics method. The acid proton forms an extraordinarily short and strong hydrogen bond with the surface oxygen. The strength of this hydrogen bond, that compares to H bonds in ice at high pressures, is at the root of a substantial redshift with respect to the typical free OH stretching frequency, which eludes its straightforward detection.

Micromechanical and Tribological Characterization of Fabricated Ti–6Al–4V Alloy Using Laser Powder Bed Fusion

Abstract In the dynamic era of advanced manufacturing technology, laser powder bed fusion (L-PBF) have gained popularity in different domains due to its capability to build parts from bulk to miniature size with higher efficiency and precision. Ti–6Al–4V, a bio-inert metal alloy, possesses a unique blend of profound mechanical and biocompatibility attributes, making it highly suitable for implant applications. This study reports the fabrication of Ti–6Al–4V alloy for implant application via the L-PBF process. The objective is to enhance the micromechanical and tribological properties of the fabricated Ti–6Al–4V component by identifying the optimal processing conditions. The fabricated component exhibited a maximum hardness of 395.26 HV and a minimum frictional coefficient of 0.3193 at 195 W laser power, 900 mm/s scanning speed, and 70 μm hatching distance. The wear-rate and absorbed wear volume were measured as 1.265 × 10−5 mm3 N−1 min−1 and 0.3162 mm3, respectively, under sliding conditions. At optimal processing state, the printed surface displayed an alpha-phase morphology with homogeneous microstructural features due to uniform melting of powder particles that improved bond strength and minimized defects. This study offers an experimental insight into operational attributes, paving the way for accelerated production of Ti–6Al–4V alloy components using the L-PBF method and tailoring tribological properties to meet specific functional requirements.

Wane-and-wax mechanism of nitrogenous disinfection byproducts with constant Cl/N peak under UV/chlorine treatment: Implication for new drinking water disinfection strategy

Nitrogenous disinfection byproducts (N-DBPs) are notorious for their serious health risks, yet nitrate (NO3-) mediates N-DBPs generation during UV/chlorine treatment remains unexplored. This study investigated the interaction of chlorine and NO3- on N-DBPs formation and developed a specific fragment-based screening method using UPLC-QTOF-MS to explore the underlying mechanism. Results showed that the chlorine-to-nitrogen (Cl/NO3--N) molar ratio significantly affects dichloroacetonitrile (DCAN) and dichloroacetamide (DCAM) generation, with peak concentrations at a Cl/NO3--N molar ratio of around 15. NO3- promotes the production of HO•, which positively correlates with DCAN and DCAM concentrations, also peaking at this ratio. Utilizing our developed method, three key hydroxyl-substituted intermediates that circumvent the previously reported “limiting-steps” in DCAN formation were identified. This reaction proceeds via a stepwise mechanism involving hydroxylation and chlorine substitution to produce hydroxyl-phenylacetonitrile and hydroxyl-chlorine-phenylacetonitrile. The conversion rate of hydroxyl-chlorine-phenylacetonitrile to DCAN was 8.6 times higher at Cl/NO3--N molar ratio of 15 compared to conditions without NO3-, attributed to the weakened bond strength of the side chain, as supported by density functional theory calculations. This study provides novel insights into the mechanistic pathways of DCAN and DCAM formation, critical for developing more effective drinking water disinfection technologies to control N-DBPs.

Enhancing mechanical properties and crack resistance of high-strength SHCC/ECC for durable transportation through ethylene-vinyl acetate polymer modification

Strain-hardening cementitious composites (SHCC) possess excellent ductility and toughness, making them suitable for reinforcement and repair projects of transit infrastructures, such as tunnel linings, bridges, and highways. Especially, polyethylene (PE) fiber is admixed to SHCC for fabricating high-strength PE-SHCC. However, the hydrophobic nature of PE fibers results in relatively weak interfacial frictional bond strength with cementitious matrix, ultimately leading to larger crack widths and wider gaps. This poses durability and safety concerns for the practical applications of PE-SHCC in transit infrastructure. In this study, ethylene-vinyl acetate (EVA) dispersible polymer is selected to address this problem. The effect of admixing EVA on mechanical and direct tensile properties of PE-SHCC is investigated. The compressive strength, first crack strength and matrix fracture toughness of PE-SHCC tended to decrease after EVA modification, however, the tensile strength and tensile strain increased significantly with doping. After that, the single fiber pullout test combined with flaw size/distribution analysis is performed to explore the improvement mechanism of PE-SHCC after EVA modification. It was found that the addition of EVA could significantly improve the interfacial transition zone (ITZ), increase the interfacial friction between PE fibers and matrix, and optimise the defect distribution within the matrix. The recommended dosage of EVA is 3–6 % comprehensive consideration of the tensile strength, strain energy, crack width, and mechanical strengths of the EVA-modified PE-SHCC. The enhancement of mechanical strengths and crack resistance in PE-SHCC contributes to the development of transit infrastructure towards greater reliability, durability, and resilience.

An efficient deep learning approach for ultimate bond strength estimations of corroded bar and concrete

Abstract The corrosion behavior of the reinforced concrete structure depends heavily on the interfacial bond behavior between steel and concrete. Over the years, the deterioration of integrated reinforced steel has weakened this bond and potentially led to structural problems. Conventional methods of bond strength evaluation, such as pullout and bond beam tests, is frequently intrusive and tedious. Therefore, there is a growing need for non-intrusive, effective, and reliable forecasting algorithms capable of assessing bond deterioration caused by corrosion. Traditional algorithms for predicting bond strength make it difficult to capture the complex nature of steel-concrete bonds. The present study proposes two different deep learning algorithms, i.e., convolutional neural networks (CNN) and long short-term memory (LSTM), for predicting maximum bond strength in the presence of corrosion. The predictive model is based on a comprehensive dataset comprising 218 datasets from previous studies encompassing diverse input and output variables for predicting the models. The models were trained and tested using the given data to improve early predictions of corrosion-induced bond degradations. The predictive model’s effectiveness was assessed by applying various performance metrics. From this study, the CNN model exhibits higher accuracy and efficiency with mean absolute error, root mean square error, and mean absolute percentage error of 0.25, 0.28, and 95.72, respectively, for predicting ultimate bond strength estimations. The findings of this study provide an accurate and robust prediction model to improve the reliability and safety of the concrete structure by enhancing the residual load-bearing capacity of the concrete structure that has undergone corrosion.

Bond behavior of confined rebar in recycled brick aggregate concrete using bending pullout test

The pertinence of recycled brick aggregate (RBA) in concrete structures largely depends on their bonding ability with the rebars. Considering the practical detailing of concrete structures where main rebars are usually confined by stirrups, this study conducted bending pullout tests on 12 beam specimens to study the influence of concrete confinement on the bond behavior of rebar in RBA concrete. The investigated variables include RBA%, rebar diameter (d), embedment length (le), and the ratio of concrete cover to rebar diameter (c/d). Bond stress-slip relationships were acquired, analyzed, and average bond strengths were compared to the AS 3600, CEB-FIP codes, and existing MacGregor's model. The average bond strength of confined specimens was nearly double that of the unconfined specimens. A progressive increase in bond strength was noticed with the presence of RBA regardless of confinement. The confined specimens also exhibited higher deformability, ductility, and toughness values than those of the unconfined beams. At 15% RBA content, the maximum toughness value of the confined specimen was 3078.1 J, while the unconfined specimens reached a value of 278.1 J, only. Similarly, the ductility of the confined beam was found in a range of 1.21–1.60 whereas the value is only 1.04–1.10 for the unconfined cases. Moreover, the confined specimens exhibited a significant number of cracks during their failure, while the unconfined specimens experienced a split type brittle failure. Nevertheless, these findings may contribute to the further development of the bond behavior of rebar in RBA-based concrete structures and thus play a role in the sustainability of construction materials.

Data and Molecular Fingerprint-Driven Machine Learning Approaches to Halogen Bonding.

The ability to predict the strength of halogen bonds and properties of halogen bond (XB) donors has significant utility for medicinal chemistry and materials science. XBs are typically calculated through expensive ab initio methods. Thus, the development of tools and techniques for fast, accurate, and efficient property predictions has become increasingly more important. Herein, we employ three machine learning models to classify the XB donors and complexes by their principal halogen atom as well as predict the values of the maximum point on the electrostatic potential surface (VS,max) and interaction strength of the XB complexes through a molecular fingerprint and data-based analysis. The fingerprint analysis produces a root-mean-square error of ca. 7.5 and ca. 5.5 kcal mol-1 while predicting the VS,max for the halobenzene and haloethynylbenzene systems, respectively. However, the prediction of the binding energy between the XB donors and ammonia acceptor is shown to be within 1 kcal mol-1 of the density functional theory (DFT)-calculated energy. More accurate predictions can be made from the precalculated DFT data when compared to the fingerprint analysis.

Measuring behavioral synchronization and spatial cohesion in the activity budgets of three adult white-handed gibbon (Hylobates lar) dyads in Huai Kha Khaeng Wildlife Sanctuary, Thailand.

Individual behavior of primates living in small groups is often seen to represent behavior of all group members due to close spatial cohesion. However, given that females expend more energy on reproduction than males (including lactation and infant carrying), females and males may exhibit different behaviors even when maintaining spatial proximity, particularly in highly seasonal or resource-poor environments. We collected 187 hours of data from three dyads (n= 6 individuals) of white-handed gibbons (Hylobates lar) living in a fruit-poor environment in western Thailand during the period of fruit scarcity. We calculated activity budgets, dyad behavioral synchronization, and dyad spatial cohesion. We hypothesized that activity budgets would differ significantly between sexes or pairs would engage in behaviors independently to provide females with an opportunity to obtain more resources. We also hypothesized that pairs would remain in close proximity. Overall, activity budgets exhibited significant variation when analyzed by sex (X2= 27.693, P ⩽ 0.001) and group (X2= 119.584, P ⩽ 0.001). Females spent less time resting and vocalizing and more time traveling compared to males. Percentages of synchronized behavior were lower than expected with only 55% of records synchronized (group B: 58.6%; group D: 58.5%; group L: 49.7%). Spatial cohesion, however, was relatively high overall with adults in the same or adjacent trees in 67.1% of paired records but significantly variable across groups (B: 89.4%; D: 73.1%; L: 48.2%; X2= 190.111, P ⩽ 0.001). We suggest that behavioral synchronization and spatial cohesion may be indicators of pair bond strength, not just the result of pair living. Given differences in activity budgets, low behavioral synchronization, and variable amounts of time pair mates spent apart, we conclude that pair mates should be considered individual actors who engage in behaviors independently from one another, particularly when coping with challenging ecological conditions.

C(sp3)‐F Bond Activation by Lewis Base‐Boryl Radicals via Concerted Electron‐Fluoride Transfer

Selective C–F bond activation through a radical pathway in the presence of multiple C–H bonds remains a formidable challenge, owing to the extraordinarily strong bond strength of the C–F bond. By the aid of density functional theory calculations, we disclose an innovative concerted electron‐fluoride transfer mechanism, harnessing the unique reactivity of Lewis base‐boryl radicals to selectively activate the resilient C‐F bonds in fluoroalkanes. This enables the direct abstraction of a fluorine atom and subsequent generation of an alkyl radical, thus expanding the boundaries of halogen atom transfer reactions.

Vibrational Spectra and Computational Study of Amyl Acetate: MEP, AIM, RDG, NCI, ELF and LOL Analysis

This work is focused on biologically active neat amyl acetate and its solutions in ethanol/heptane. According to the experimental results, when the concentration of amyl acetate in the amyl acetate-ethanol solution decreases, the additional band appears on the low-frequency side. The primary reason for the formation of such additional band is the intermolecular hydrogen bonding between amyl acetate and ethanol. In the amyl acetate-heptane solution, as the concentration of amyl acetate in the solution decreases, the band corresponding to the C=O stretching vibrations shifted to a higher frequency. This is explained by the fact that heptane breaks intermolecular interactions in solution, resulting in a simpler spectral band corresponding to the C=O stretching vibrations. Calculations are also used to study interactions in amyl acetateethanol complexes and their spectral manifestations. When the complex formation energies are calculated, this energy increases with the number of molecules, but the average hydrogen bond energy per one bond remains unchanged. The density functional theory (DFT) method is used to analyze molecular structural parameters: Mulliken atomic charge distribution; thermodynamic parameters; molecular electrostatic potential (MEP) surface; atoms in molecules (AIM) analysis; quantum chemical parameters such as reduced density gradient (RDG) and noncovalent interaction (NCI) analysis; electron localization functions (ELF) analysis; and localized orbital locator (LOL) analysis.

Quantification of Interfacial Voids Using Positron Annihilation Spectroscopy for Mechanism Study on SiCN Bonding and SiN Bonding

Abstract Hybrid bonding for 3D integration requires reliable direct bonding interface of dielectrics. Lately, the spotlight has focused on SiCN/SiCN bonding considering its superior bonding performance by the dangling bonds-facilitated nanovoid closure mechanisms, but it is reported to be sensitive to reactive species especially under the high temperatures. Recent work proposed SiN/SiO2 asymmetric bonding showing a void-free bonding interface and bond energy higher than 2.5 J/m2 as a promising candidate for direct bonding applications. Interestingly, we observed opposite bonding behaviors between SiCN and SiN in corresponding symmetric bonding pair and asymmetric bonding pair (with SiO2). Thus, a comprehensive fundamental understanding on the bonding of different dielectrics is needed to guide the specifications of the bonding layer for enabling a void-free and highly reliable bonding interface. In this study, we systematically quantified the nanovoids in the bonding interface of SiCN/SiCN, SiCN/SiO2, and SiN/SiO2 through positron annihilation spectroscopy and simulation, dangling bond formation by electron spin resonance, and the film passivation property by quasi-steady-state photoconductance. By correlating the film properties and bonding performance, the model of SiCN bonding is extended towards its SiCN/SiO2 asymmetric bonding, and a new model of the nanovoid closure mechanism in SiN bonding is first-time proposed.

Analysis of the Impact and Mechanism of Polyacrylate-Based Composite Paste on the Performance of Recycled Aggregate

This study developed three composite slurries for coating recycled aggregate by incorporating polyacrylate emulsion, fly ash, and gypsum into a cement-based mixture. The filling and pozzolanic effects of fly ash help to improve microcracks in the recycled aggregates. The polyacrylate emulsion forms a strong bonding layer between the cement matrix and the aggregates, enhancing the interfacial bond strength. Based on relevant studies, the following mix designs were developed: Slurry 1 consists of pure cement paste; Slurry 2 contains 15% fly ash and 3% gypsum added to the cement paste; Slurry 3 adds 22% polyacrylate emulsion to the slurry. The study first compared the effects of the three composite slurries on the crushing value and water absorption of recycled aggregates, and then analyzed their impact on the mechanical properties, permeability, and drying shrinkage of concrete. Finally, the mechanisms behind the enhancement were investigated using the Vickers Hardness Test (HV), Mercury Intrusion Porosimetry (MIP), and scanning electron microscopy–energy-dispersive spectroscopy (SEM-EDS). The results showed that the polyacrylate emulsion composite slurry had the most significant improvement effect. For recycled aggregate AL, the crushing value decreased from 28.8% to 22.5% and the saturated surface–dry water absorption decreased from 15.1% to 13.8% after cement slurry modification. After coating with the composite slurry, the crushing value further dropped to 18.2% and the water absorption to 9.5%. Two aspects of the performance of recycled aggregates are enhanced with the polymer composite slurry: first, fly ash provides nucleation sites for CH, reducing the tendency for directional CH alignment. Second, the long chains of PAE (polyacrylic ester) encapsulate cementitious particles, effectively filling surface defects on the recycled aggregates, improving the bonding strength at the new-to-old interface, and significantly enhancing the performance of both recycled aggregates and recycled concrete.

Magnetic pulse welding for dissimilar metals and corrosion studies at interface

Magnetic Pulse Welding (MPW) is an eco-friendly, solid-state welding method that utilizes high-velocity impacts. It operates without the necessity for fillers or flux and generates no harmful fumes. The process harnesses electromagnetic forces to weld two dissimilar job pieces by rapidly discharging current (∼100 µs) from a capacitor bank into a tool coil. This action produces a significant magnetic field (∼35 T) in the tool coil, which induces eddy currents in the job pieces, causing the outer piece to strike the inner piece at high velocities. Dissimilar metal joints such as Al-Cu, Cu-SS304, Al-SS304 and Ti-SS304 were successfully welded under these conditions using a 200 kJ MPW system. The resulting joints passed helium leak tests and exhibited a characteristic wavy morphology at the interface. Hardness measurements are conducted to investigate the mechanical properties of these joints, which provide valuable insights into the weldability and interface bond strength. Corrosion behaviour was evaluated, revealing bimetallic corrosion at the interface area. The welds were found to be flawless, instantaneous, and stronger than the base materials, confirming the potential of MPW for joining dissimilar metals with minimal corrosion rate of 0.441 mpy attained for the Ti-SS304 joint.

Research Progress of Human Biomimetic Self-Healing Materials.

Humans can heal themselves after injury, which inspires researchers to develop bionic self-healing materials. Such materials not only equipped with the self-repair capacities akin to those of the human body, but also emulate the mechanical properties of human organs, including the tensile resilience of muscles, the fatigue resistance of skin, and the elevated modulus typical of cartilage. Based on the design concept of imitating the structure of human organs, the bionic self-healing material perfectly solves the problem of poor mechanical properties of self-healing materials caused by weak bond energy and inter-chain flow. This review discusses various organ-inspired self-healing materials in detail, summarizes their synthetic principles and introduces their fascinating mechanical properties. Finally, the application prospects of bionic self-healing polymer materials, such as bio-strain sensors, self-healing anticorrosive coatings, biomedical detection, etc., are outlined. Considering the excellent comprehensive performance and multi-functions of human biomimetic self-healing polymers, more outstanding sustainable materials will be developed, accelerating research progress in self-healing materials and realizing environmentally friendly products in multiple fields.

Bond strength of resin-based restorative materials to fast-setting calcium silicate cement using different resin adhesive systems.

This study assessed the bond strength of resin-based restorative materials to fast-setting calcium silicate cement (Aarhus Uinversity, Denmark) when treated with each of two one-bottle universal adhesive systems. The cement surface (N=256) was treated with a self-priming adhesive and a self-etch phosphate monomer-containing adhesive with and without etching of the cement surface. Specimens then received either resin composite or compomer restorative materials (n=32). The bond strength was measured after 1 day and 1500 thermocycles (n=16). The failure type was visually inspected. The cement-adhesive-restorative material interface was visualized using scanning electron microscopy (SEM). The data were analyzed using multiple linear regression. Restorative material type, resin adhesive system, and thermocycling had a statistically significant effect on the bond strength. Compomer restorative material and self-etch universal adhesive system demonstrated statistically significantly higher bond strength values to fast-setting calcium silicate cement, predominantly exhibiting cement cohesive failure. Etching the cement surface enhanced the bond strength of the self-priming universal adhesive. Thermocycling significantly reduced the bond strength. SEM showed self-etch universal adhesive seemingly diffused over the etched cement surface compared to other groups. Self-etch phosphate monomer-containing universal adhesive and compomer resulted in the highest bond strength to fast-setting calcium silicate cement.

The Effect of Silver Nanoparticles on Bond Strength of Calcium Silicate-Based Sealer: An In Vitro Study

The aim of this study was to evaluate the bond strength of the calcium silicate-based sealer (CSS) modified with the silver nanoparticles (AgNPs) using the single-cone technique (SC) and the continuous wave condensation (CWC) technique, measured by a universal testing machine. The AgNPs and the modified sealers were characterized by scanning electron microscopy and transmission electron microscopy. One hundred single-rooted extracted human permanent teeth with a single root canal were cleaned and shaped with a Protaper Next system. The teeth were randomly divided into four groups (n = 25) as follows: Group 1, canals were obturated using the SC technique with TotalFill® BC Sealer. Group 2, canals were obturated using the SC technique with TotalFill® BC Sealer mixed with AgNPs. Group 3, canals were obturated using the CWC technique with TotalFill® HiFlow BC Sealer. Group 4, canals were obturated using the CWC technique with TotalFill® HiFlow BC Sealer mixed with AgNPs. After two weeks, 1 mm-thick dentin slices were cut and exposed to a push-out bond strength test using a universal testing machine. Specimens were examined under a digital microscope to determine the mode of failure. Statistical analysis was performed using ANOVA and Tukey multiple comparison tests (p < 0.05). The nanoparticle characterization revealed a spherical morphology with no obvious aggregations. The results showed that group 4 had the highest dislodgement resistance compared to all groups (p < 0.05). Group 4 was significantly higher in push-out bond strength value than group 1 (p < 0.001) and group 3 (p < 0.003), but not significantly higher than group 2. Cohesive failure was the most prevalent failure mode among all groups. It can be concluded that the incorporation of silver nanoparticles into the calcium silicate-based sealer significantly increased the bond strength. The warm obturation approach demonstrated significantly higher resistance to dislodgment as compared to the single-cone technique.

Development of Biodegradable and Recyclable FRLM Composites Incorporating Cork Aggregates for Sustainable Construction Practices

Reducing energy consumption in the building sector has driven the search for more sustainable construction methods. This study explores the potential of cork-modified mortars reinforced with basalt fabric, focusing on optimizing both mechanical and hygroscopic properties. Six mortar mixtures were produced using a breathable structural mortar made from pure natural hydraulic lime, incorporating varying percentages (0–3%) of cork granules (Quercus suber) as lightweight aggregates. Micro-computed tomography was first used to assess the homogeneity of the mixtures, followed by flow tests to evaluate workability. The mixtures were then tested for water absorption, compressive strength, and adhesion to tuff and clay brick surfaces. Adhesion was measured through pull-off tests, to evaluate internal bonding strength. Additionally, this study examined the relationship between surface roughness and bond strength in FRLM composites, revealing that rougher surfaces significantly improved adhesion to clay and tuff bricks. These findings suggest that cork-reinforced mortars offer promising potential for sustainable construction, achieving improved hygroscopic performance, sufficient mechanical strength, internal bonding, and optimized surface adhesion.