Interfacial Bond Strength Research Articles

Debonding failure of continuously reinforced bonded concrete overlay at early ages

ABSTRACT The structural behaviour and debonding mechanism of continuously reinforced bonded concrete overlay (CRBCO) on deteriorated concrete pavements subjected to environmental loadings are evaluated analytically and experimentally. It is shown that the temperature gradient in concrete significantly affects the debonding potential at the interface between CRBCO and existing continuously reinforced concrete pavements (CRCPs) and that the normal stress at the interface is the dominant cause of debonding failure. The results of factorial experiment show that the debonding potential can be reduced by decreasing the elastic modulus, coefficient of thermal expansion (CTE) and thickness of CRBCO, and by increasing the interfacial bond strength.

Effect of Chlorhexidine on Immediate and Delayed Bond Strength between Resin and Dentin of Primary Teeth: A Systematic Review and Meta-Analysis.

Objectives: The purpose of this study was to systematically review the literature and use meta-analysis to investigate whether chlorhexidine (CHX) application after acid etching as an adjunct treatment has any influence on the immediate and delayed bond strength to primary dentin. Materials and Methods: In this review, PubMed, ISI (all data bases), Scopus and Cochrane were searched according to the selected keywords up to April 30, 2018. The full texts of all published articles that met our primary inclusion criteria were obtained. The studies were analyzed in two parts: in vitro studies that evaluated the effect of CHX application during the bonding procedures (application after acid etching) on immediate and delay dentin bond strength of resin-dentin interface. Results: The initial search yielded 214 publications, of which 8 were selected after thorough methodological assessment. None of the clinical studies fulfilled the eligibility criteria. Our results indicated that in comparison to the control group, CHX significantly reduced immediate resin-dentin bond strength (P=0.043). These values were increased after aging (P<0.001). Conclusion: Based on this invitroMeta-analysisCHX application, improveresin-dentin bond strength durability in primary teeth.

Nanoscale insights into the interfacial characteristics between calcium silicate hydrate and silica

The interfacial characteristics between cement paste and silica are far from being fully understood, especially from the nanoscale perspective. Herein, molecular models were used to provide comprehensive insights into the interfacial characteristics between calcium silicate hydrate (C-S-H, the main binding phase of cement paste) and silica. Chemically, various types of bonds existed at the interface, including H-bonds and Ca–O bonds, and proton (H+) exchange occurred between C-S-H and silica. An increase in the water content of C-S-H could depress the deprotonation of the Si-OH groups on the silica surface. Structurally, an atomic-level interfacial transition zone (ITZ) with a low density was identified, which was attributed to the rich presence of –OH groups at the C-S-H–silica interface. The water molecules and calcium ions in the ITZ diffused faster than those in the bulk C-S-H. Mechanically, the interfacial bond strength was inversely related to the water content of C-S-H, with the higher water content reducing the interfacial interactions. Under loading, the interfacial fracture underwent three stages: crack propagation, atomic chain bridging (responsible for the interfacial residual strength), and complete failure. These atomic-level findings provide hitherto unknown mechanisms of the interfacial interactions between cement paste and silica.

Interfacial bonding performance of textile reinforced ECC and seawater sea-sand concrete under a dry-wet environment

In order to promote the application of cementitious composites in the marine environment, it is crucial to clarify the interfacial bonding properties of cementitious composites to concrete. Therefore, the interfacial bonding performance of a new cementitious composite, textile reinforced ECC (TRE), to seawater sea-sand concrete (SWSSC) in a chloride salt dry-wet environment was investigated by single shear test. The interface behavior was evaluated from the failure modes, average bond strength, load-slip curves, and fracture energy of TRE-SWSSC interface. The main research factors included the erosion environment, the thickness of TRE composite, and the dry-wet cycles. The study showed that the failure mode of specimens with a small thickness of TRE composite are mainly the fracture and sliding of matrix in the free length of TRE. The failure pattern of the TRE-SWSSC interface with 20 mm thickness changed from the fracture and sliding of matrix in bond length of TRE to that in free length of TRE with the increase of dry-wet cycles. And the failure of specimens in immersion environment was interfacial peeling. The average bond strength of TRE-SWSSC interface increased with the thickness of TRE. After 270 days of environmental action, the interfacial average bond strength in the dry-wet environment was 15.94 % higher than that in the immersion environment. The load-slip curves were smoother for specimens with smaller TRE thickness, and the descending section of the load-slip curves became steeper with the increase of TRE thickness. The interfacial fracture energies of the specimens with different TRE thicknesses showed different growing trend with the dry-wet cycles. With the increase of the dry-wet cycles, the interfacial fracture energy of the specimens with a TRE thickness of 10 mm gradually increased, but the interfacial fracture energy of the specimens with a TRE thickness of 20 mm gradually decreased.

Effects of alloying elements on diamond/Cu interface properties based on first-principles calculations

Diamond/copper composites with high thermal conductivity and a variable thermal expansion coefficient are promising materials for thermal management applications. However, achieving the desired thermal conductivity of the composite material is difficult due to detachment or weak bonding between diamond and Cu. The interfacial properties of diamond/Cu composites can be improved using metal matrix alloying methods. In this study, we investigate the effects of alloying elements (B, Cr, Hf, Mo, Nb, Si, Ti, V, Zr) on the interfacial properties of diamond/Cu using first-principles calculations. Results showed that all alloying components could increase the interfacial bonding of diamond/Cu. Analysis of the electronic structure revealed that increased interfacial bonding strength after doping was the result of the stronger bonding of the alloying element atoms to the C atoms. The C atoms in the first layer of diamond at the interface formed wave peaks near the Fermi energy level after doping with B or Si atoms, facilitating electron–phonon interaction at the interface. The phonon properties of B4C and SiC were similar to those of diamond, which facilitated phonon–phonon coupling. B and Si were shown to be better alloying elements when interfacial bond strength and heat transfer were considered.

Bonding performance monitoring between CFRP and timber column interfaces based on piezoelectric ceramics

To address the problem that carbon fibre reinforced polymer (CFRP) composite material is not easy to directly measure the bond strength of the CFRP-timber column interface during the process of strengthening timber column, a real-time monitoring method of CFRP-timber interface bond strength based on piezoelectric ceramic active sensing is proposed to determine the interface bond strength directly from the structural response signal. A total of 15 specimens were designed for the active monitoring test and tensile test, and the monitoring signals at different enhancement times were compared and analysed using wavelet packets, power spectral density, and short-time Fourier transform, and it was found that the amplitude and power spectral density of the signals increased as the reinforcement time increased. The mapping relationship between wavelet packet energy and bond strength is obtained, providing a more efficient and robust way of monitoring the bond strength between CFRP and timber columns during reinforcement.

Investigating on Molding Process of Steel-polyurethane Flexible Composite Components and the Interfacial Bonding Strength

Investigating on Molding Process of Steel-polyurethane Flexible Composite Components and the Interfacial Bonding Strength

The interfacial reaction between diamond (100) surface and CuNi-based filler alloys containing Cr by first-principles calculations

Brazed diamond tools have the advantages of high holding strength for diamond abrasives, superior grinding performance, formability, etc. The elements used commonly in filler alloys such as Cr, Cu, and Ni have an important impact on the interfacial bond strength and diamond thermal damage. In this work, the interactions between Cu, Ni, and Cr of the filler alloy and the diamond (100) surface were investigated using first-principles calculations. The results indicated that the adsorption energy of Cu adsorbed on the diamond (100) surface was low, suggesting that C atoms are extremely difficult to dissolve into Cu-based filler alloys, which makes Cu-based filler alloys less wettable with diamond. While the adsorption energy of Ni adsorbed on the diamond (100) surface was greater, which may form Ni 3 C weak carbide. Therefore, Ni-based filler alloys are usually wettable with diamonds. However, Ni 3 C of poor stability may decompose C atoms at the interface, which may lead to greater corrosion of diamonds. The adsorption energy of Cr adsorbed on the diamond (100) surface was the highest among Cu, Ni, and Cr, while the co-adsorption of Cr and C can grow into stable carbides. With the extension of time, the carbides can grow to form continuous layers of carbides. The results are generally consistent with the experimental results. • Analysis of graphitization on diamond surfaces using first-principles calculations. • The co-adsorption and deposition processes of Cr and C were investigated, which provided the conditions for the formation of chromium carbides. • Interfacial reaction processes, such as C precipitation and carbides nucleation growth, were investigated at the atomic level using first-principles calculations.

Bond strength prediction of UHPC-NSC interface

The application of ultra-high-performance concrete (UHPC) on top of normal-strength concrete (NSC) is a practical rehabilitation approach to maintaining degraded and damaged concrete members. However, a successful repair operation and consequent adequate performance are very much dependent on the ability of the interface between UHPC and NSC to present a superior performance of bonding under various surface conditions. Consequently, predicting the strength of the bond at the interface joining the existing NSC and the newly placed overlaying UHPC - with sufficient certainty - has become a vital and required step in assessing and maintaining UHPC rehabilitated NSC structural elements. In this work, Artificial Neural Network (ANN as well as Gene Expression Programming (GEP methods are utilized to predict the bond strength between the overlaying UHPC and the substrate NSC using a comprehensive database set consisting of 264 experimental data points gathered from the literature. A parametric ANN analysis is performed to examine and assess the effect of each parameter on the interfacial bond strength. The following five factors are identified as key parameters through the GEP and ANN analyses: curing method, age of UHPC, the compressive strength of NSC, interfacial surface treatment, and moisture conditions. The developed ANN and GEP models have good accuracy and closer predictions of the bond strength of the slant shear test and the splitting tensile strength with root mean square error (RMSE) values of 5.0, 4.3, and coefficient of variation (COV) values of 37%, 24%, respectively.

Influence of bioceramic intracanal medication on the bond strength of bioceramic root canal sealer.

To investigate the influence of the remaining volume of a new intracanal medication based on bioceramic compounds on the bond strength (BS) and formation of an adhesive interface between calcium silicate-based and epoxy resin-based root canal sealers. For this purpose, the specimens were distributed according to the intracanal medication (n = 26): Bio-C Temp (BCT) and Ultracal XS (UXS). The roots were scanned in microCT, and after 7 days, the medication was removed. Then a new scan was performed to evaluate the volume of medication remaining. Subsequently, 40 specimens were redistributed into 2 subgroups (n = 10) and filled according to the sealer used: AH Plus (AHP) and Bio-C Sealer (BCS), to assess the bond strength by using the push-out test, and the adhesive interface by confocal laser fluorescence microscopy (CLSM) and scanning electron microscopy (SEM). The t test showed a smaller remainder of BCT (1.77 ± 0.86) compared with UXS (10.47 ± 5.78), irrespective of the root third evaluated. The BS showed that teeth with BCT + BCS had higher bond strength values (3.70 ± 1.22) when compared to the other groups: BCT + AHP (2.15 ± 1.07), UXS + BCS (3.18 ± 1.09) and UXS + AHP (2.11 ± 1.02) (p<0.001). The cervical third had higher BS when compared with the middle and apical thirds (p < 0.001), and higher number of adhesive failures. The adhesive interface in SEM and CLSM images showed better adaptation for the association between BCT + BCS. Intracanal medication and silicate-based endodontic sealer appeared to interact chemically by forming a biomineralizing layer, allowing for an increase in the bond strength and forming an adhesive interface between the materials, with no or less gap formation.

INTERFACIAL BOND STRENGTH BETWEEN MICRO-SYNTHETIC FIBER-REINFORCED PATCH REPAIR MORTAR AND CONCRETE SUBSTRATE BASED ON PUSH-OFF TEST

A micro synthetic fiber-reinforced mortar has been developed as a patch repair material. The bond strength of this material is a crucial parameter for successful repair applications. The state of stress occurring at the interfacial plane between the repair material and the concrete substrate influences the bond strength requirements of patch repair material. Therefore, bond strength envelope criteria should be established using, among others, the interfacial adhesion and friction coefficient parameters. This research aims to determine the composite’s interfacial bond strength parameters (adhesion and friction coefficient) between micro-synthetic fiber-reinforced patch repair mortar (MSFRPRM) and concrete substrate by push-off tests. At this stage, the smooth joint texture limits the investigation. The fiber volume fraction and age of repair are considered. The tests were conducted at the age of 1, 3, 7, and 28 days. In addition to the laboratory experiment, this research used ATENA Science GiD to numerically simulate the push-off test and study the influence of the fiber volume on the adhesion and friction coefficient. The results show that at a fiber volume of 0.06%, the adhesion and friction coefficients increase from 1.15 to 2.33 MPa and 0.74 to 0.85, respectively, corresponding to age. Numerical simulation indicates that the maximum adhesion and friction coefficient occurs at the fiber volume fraction of 0.06%. Thus, the overall simulation results can be used in the future as a parameter to establish MSFRPRM and concrete substrate bond strength envelopes that will be useful for evaluating the suitability of MSFRPRM as repair materials under various states of stress. Keywords: Bond Strength, Concrete Patch Repair, Concrete Substrate, Micro-Synthetic Fiber-Reinforced Repair Mortar, Push-Off Test DOI： https://doi.org/10.35741/issn.0258-2724.58.1.20

Molecular insights into the interfacial adhesion mechanism between carbon nanotubes and epoxy resin.

In recent years, carbon nanotubes (CNTs) have garnered widespread attention and have been deemed the preferred option for the creation of epoxy composites, owing to their outstanding mechanical properties. Despite this, the interaction between pure CNTs and epoxy resin is primarily dependent on van der Waals forces and therefore, the interfacial forces are weak, making it challenging for effective load transfer. To enhance the mechanical properties of the composites, surface functionalization is often deemed a more favorable method for improving interfacial bond strength. This study employs molecular dynamics simulations to examine the interfacial bonding characteristics between functionalized CNTs and epoxy resin. The results demonstrate that functional group modification can significantly improve the interfacial adhesion between CNTs and epoxy resin, and the incorporation of functional groups can enhance the crosslinking degree of the epoxy resin at the interface. The hydrogen bond network established between the CNTs and epoxy resin after functional group modification, and the high stability of the bond cooperation, are factors contributing to the excellent interfacial performance.

Contribution of fiber–matrix interface enhancement on flexural properties of Ultra–high–performance concrete

Herein, the effect of steel fiber–matrix interface reinforcement on the macromechanical properties of ultra–high–performance concrete (UHPC) is studied. Two types of nano–SiO2–coated steel fibers are prepared using the sol–gel method. Single–fiber pull–out tests are conducted, and flexural and compression tests of UHPC with fiber contents of 1 vol%, 2 vol%, and 3 vol% are performed. The results reveal that the enhancement of interfacial adhesion significantly influences the macromechanical properties of UHPC. However, the granular nano–SiO2 on the surface of the modified steel fibers increases the roughness of the steel fiber and reduces the fluidity of fresh UHPC mixture. Analysis of the images of crack section reveals that appropriate vibration can reduce the influence of the steel fiber surface roughness on the distribution of fibers in UHPC. A flexural load–deflection response model for UHPC that considers steel fiber–matrix interface bond strength and fiber orientation is established.

Uneven distribution of interfacial bond stress in steel fiber-reinforced concrete-encased steel composite structures

To solve the congestion of reinforcement and the difficulty of concrete pouring in concrete-encased steel (CES) structure, steel fiber-reinforced concrete-encased steel (SFRCES) structure was proposed. Push-out tests of 34 SFRCES specimens were carried out in this paper to study the interfacial bond stress distribution, and load-displacement curves were obtained. The interfacial ultimate bond strength calculated based on load-displacement curve is much greater than 0.2 MPa which is the interfacial design shear strength of composite steel and concrete structure in Eurocode 4. This illustrates that the design of SFRCES structure is partial to safety. Furthermore, different from the previous method using the assumption of uniform distribution of interfacial bond stress, the interfacial local bond stress was obtained based on strain data and mechanical derivation in this paper. Moreover, the influence of steel fiber volume rate, embedded length of steel, and thickness of concrete on the distribution of interfacial bond stress was analyzed by defining the uneven coefficient of interfacial bond stress distribution. Analysis results provide a theoretical basis for the design of SFRCES structure and lay a foundation for the application of SFRCES structure in practical engineering.

Enhancing the interfacial bond strength of aluminum/polymer laminated film of the soft package lithium‐ion battery through polydopamine surface modification

AbstractThe aluminum (Al) foil used in Al/polymer laminated film of the soft package lithium‐ion battery (LIB) is widely treated with a hexavalent chromate conversion coating to increase the adhesive strength and durability of the adhesive joint. Given that hexavalent chromate is toxic and carcinogenic, a novel and chromate‐free method was developed in this study for surface modification of the Al foil using polydopamine (PDA) functionalization after titanium (Ti) chemical conversion. Ti conversion favors the deposition of PDA and introduces more functional groups of PDA on the Al surface. A novel polypropylene‐based hot melt adhesive, MAH‐g‐(PP/PBE), was prepared by melt grafting of maleic anhydride on the blend of polypropylene and propylene‐based elastomer for use as the inner adhesive of Al/polymer laminated film. Then, treated Al foil/MAH‐g‐(PP/PBE) composites were prepared and their interfacial adhesive strengths were investigated. The results show that the amine and catechol groups of PDA improve the interfacial adhesion between adhesive and Al foil by improving the wettability and interfacial interaction. The peel strength between MAH‐g‐(PP/PBE) and PDA functionalized Al foil after Ti conversion treatment can reach 3.55 N/mm, which is increased by 322% compared with that between MAH‐g‐PP and untreated Al foil. PDA functionalization after Ti chemical conversion and MAH‐g‐(PP/PBE) have great potential to improve interfacial adhesion of Al/polymer laminated film used in LIB package.

Effect of Resin Cement at Different Thicknesses on the Fatigue Shear Bond Strength to Leucite Ceramic.

This in vitro study was performed to evaluate fatigue survival by shear test in the union of leucite-reinforced feldspathic ceramic using different cement thicknesses. Leucite-reinforced glass ceramics blocks were sectioned in 2-mm thick slices where resin cylinders were cemented. The samples were distributed in two experimental groups (n = 20) according to the cement thickness (60 and 300 μm). The specimens of each group were submitted to the stepwise fatigue test in the mechanical cycling machine under shear stress state, with a frequency of 2 Hz, a step-size of 0.16 bar, starting with a load of 31 N (1.0 bar) and a lifetime of 20,000 cycles at each load step. The samples were analyzed in a stereomicroscope and scanning electron microscopy to determine the failure type. There is no significant difference between the mean values of shear bond strength according to both groups. Log-rank (p = 0.925) and Wilcoxon (p = 0.520) tests revealed a similar survival probability in both cement layer thicknesses according to the confidence interval (95%). The fracture analysis showed that the mixed failure was the most common failure type in the 300-μm thickness group (80%), while adhesive failure was predominant in the 60-μm thickness group (67%). The different cement thicknesses did not influence the leucite ceramic bonding in fatigue shear testing; however, the thicker cement layer increased the predominance of the ceramic material failure. The resin cement thicknesses bonded to leucite ceramic did not influence the long-term interfacial shear bond strength, although thicker cement layer increased the ceramic material cohesive failure. Regardless the cement layer thickness, the shear bond strength lifetime decreases under fatigue.

Achieve High Interfacial Bonding Strength of Ti/Al Laminated Composite at Room Temperature via Electropulsing-Assisted Ultrasonic Additive Manufacturing

Achieve High Interfacial Bonding Strength of Ti/Al Laminated Composite at Room Temperature via Electropulsing-Assisted Ultrasonic Additive Manufacturing

Experimental Study of Interfacial Bond Properties between CGM and Existing Concrete

To ensure that the cementitious grouting material (CGM) layer and existing concrete work together, the interfacial bond strength between CGM and normal concrete substrate was experimentally investigated by conducting direct and slant shear tests. The effects of connection interface form, concrete strength, interface shear key, and shear angle on the bond strength of CGM and normal concrete were discussed in detail. The results showed that for composite specimens, the interfacial bond strength was the highest for the triangular interface form, followed by the trapezoidal interface and smooth interface, which had the lowest. The interfacial bond strength increased as the existing concrete’s strength increased; the interfacial bond strength could be greatly improved under shear load in the slant section or when the shear key was set at the interface. Moreover, the interfacial bond strength increased with the increase in the shear angle. The interfacial bond–slip curves were analyzed, and a bond–slip model of the interface between CGM and concrete was proposed. A certain value of interfacial bond stiffness was also recommended.

Evolution mechanism of microstructure and bond strength based on interface diffusion and IMCs of Ti/steel clad plates fabricated by double-layered hot rolling

Ti/steel clad plates have good corrosion resistance and lower titanium cost. However, the low interfacial bond strength severely restricts their wide application. In this study, a new process is proposed for preparing Ti/steel clad plates with high bond strength by employing double-layered slab assembly and hot rolling. The effect of temperature on bond strength is systematically studied. The results show that the shear strength initially increases and then decreases with increasing temperature from 700 °C to 950 °C. The maximum strength value of 311 MPa is obtained at 850 °C with a reduction rate of 30% in a single pass. The mechanism analysis shows that the bond strength is affected by temperature in terms of metal deformation, elemental diffusion and intermetallic compound (IMC) formation. In addition, the shear strength depends on different degrees of dislocation strengthening and recrystallization in the titanium matrix when the fracture is located at titanium matrix near the interface. Finally, a phenomenological prediction mechanism-based model is developed to describe the relationship between the temperature and the bond strength. This research can provide guidance for the hot rolling preparation of Ti/steel clad plates with high bond strength. • Ti/steel plates were fabricated by double-layered slab assembly and hot rolling. • A superior bond strength of 311 MPa was obtained at 850 °C. • Microstructure evolution was characterized. • Bonding mechanism at different temperatures was analyzed. • A phenomenological prediction mechanism-based model was proposed.

Research on the Interaction Capability and Microscopic Interfacial Mechanism between Asphalt-Binder and Steel Slag Aggregate-Filler

To explore the applicability of steel slag porous asphalt mixture, the interaction capability and microscopic interfacial mechanism between asphalt-binder and steel slag aggregate-filler were investigated in this laboratory study. These objectives were accomplished by comparing and analyzing the differences between steel slag and basalt aggregates in interacting with the asphalt-binder. The study methodology involved preparing basalt and steel slag asphalt mortar to evaluate the penetration, ductility, softening point, toughness, and tenacity. Thereafter, the interaction capability between the asphalt-binder and aggregates was characterized using the interaction parameters of the asphalt mortar obtained from dynamic shear rheometer (DSR) testing. For studying the functional groups and chemical bonding of the asphalt mortar, the Fourier Transform infrared (FTIR) spectrometer was used, whilst the interfacial bonding between the asphalt-binder and aggregates was analyzed using the scanning electron microscope (SEM). The corresponding test results indicated that the physical and rheological properties of the two asphalt mortars were similar. However, whilst the FTIR analysis indicated domination through chemical reactions, the interaction capability and interfacial bonding between the asphalt-binder and steel slag aggregates exhibited superiority over that between the asphalt-binder and basalt aggregates, with pronounced adsorption peaks appearing in the steel slag asphalt mortar spectrum. On the other hand, the SEM test revealed that, compared with the basalt, the micro-interfacial phases between the steel slag and asphalt-binder were more continuous and uniform, which could potentially enhance the interfacial bond strength between the asphalt-binder and aggregates (filler).