Bond Strength Degradation Research Articles

Bond behavior of plain round bar embedded in high ductile concrete under monotonic and cyclic loading

AbstractBond behavior is the basis of combined action of steel bar and high ductile concrete (HDC), which has an important effect on the mechanical performance of reinforced HDC structures. In this paper, nine groups of pullout specimens were tested to investigate the bond behavior and degradation mechanism of plain round bar embedded in HDC under monotonic and cyclic loading. The design parameters included HDC compressive strength, HDC flexural toughness and anchorage length. Experimental results indicated that only a small free end slip occurred for specimens with plain round bar when the maximum bond stress was reached. Bond strength of polyethylene fiber specimens was 1.67 times that of polyvinyl alcohol fiber specimens. Compared with the monotonic specimens, the cyclic specimens exhibited an obvious degradation in bond strength and residual bond strength, and the degradation degree of former was more serious than that of latter. Besides, it also should be noted that the HDC compressive strength had a great influence on the energy dissipation capacity of cyclic specimens. Based on the test results, a calculating formula of bond strength was built. Then this paper proposed a bond stress‐slip relationship model for the plain round bar embedded in HDC under monotonic loading.

Bond strength degradation in concrete cracked by expansion agent filled pipes

AbstractIn this study, the bond behavior of corroded reinforced concrete was investigated by conducting pull‐out tests on concrete specimens with variable induced crack widths and different splitting modes. To simulate cracks due to corrosion and focus on their effect on bond strength degradation, a novel method using expansion agent filled pipes is proposed. With the increase of the crack width over elapsed time from filling the aluminum pipe with an expansion agent, a target crack width was obtained. The results confirm that the type of splitting greatly influences the reduction in bond strength with deterioration of bond strength more severe in “Side‐split” than in “Single‐split.” Furthermore, using the surface crack width as a variable, empirical formulas to predict bond strength degradation due to corrosion of rebar are proposed. These prediction models give a good correlation when compared to the available literature.

Numerical simulation of the influence of bond strength degradation on the behavior of reinforced concrete beam-column joints externally strengthened with FRP sheets

Limited information is known about the effects of bond strength degradation during installation on the bond's quality and performance between fiber-reinforced polymer (FRP) reinforcement and substrate material. This research study's primary focus is to investigate the efficiency of the external FRP composites in rescuing the structural performance and controlling the mode of failure of the reinforced concrete (RC) beam-column joint with different bond strength degradation percentages nonlinear finite element analysis (NLFEA). Firstly, the RC beam-column model was validated against the published experimental results and then was expanded to consider the effect of the degradation percentages in bond strength between concrete and FRP composite (0 % (Fully bond), 10 %, 20 %, 30 %, 40 %, 50 %, 60 %, 70 %, 80 %, 90 %, and 100 % (control or un-strengthened joint). The structural performance was evaluated in terms of failure mode, stress distribution, pulling and pushing ultimate load capacity and corresponding displacement, horizontal load-displacement hysteretic loops, horizontal load-displacement envelopes, displacement ductility, energy dissipation, stiffness degradation, and equivalent hysteretic damping factor. The NLFEA results showed that the FRP strengthening technique with bond strength degradation percentages less than 30 % enhanced the cyclic performance (higher load capacity, larger horizontal displacement, higher displacement ductility, higher energy dissipation, and slower secant stiffness degradation). Also, the utilized FRP method with bond strength degradation percentage less than 30 % performed well in eliminating any surface debonding or buckling in the FRP composite because of the proper lateral support provided for the strengthening sheets. Finally, the bond strength degradation percentage less than 30 % could significantly enhance the deficient joints' seismic performance under strong beam-weak column conditions by changing its behavior to a more ductile one, including the beam flexural hinging. Moreover, the relocation of a plastic hinge in the beam provided more lateral strength for the joint specimens.

Investigating the nonlinear performance of corroded reinforced concrete beams

Reinforced concrete beams are one of the primary horizontal members that undergo large flexural stresses in a reinforced concrete structure. According to capacity design concept, the beams are designed to suffer damage before the columns of the structure. However, such damage in beams and subsequent failure sometimes occurs prematurely if the rebars in the beam have undergone corrosion. Corrosion of reinforcement is one of the primary factors responsible for degradation of RC structure that significantly affects its intended service life. The present study is an effort to assess the performance of corroded RC beams considering the primary effects, such as bond strength degradation, spalling stresses induced on concrete surrounding rebars, and reduction in the cross-sectional area of the rebars. A 3D nonlinear finite element model has been developed to simulate the corrosion induced spalling stress along with bending stress. The effect of the combined bending and spalling stresses are identified for the corroded RC beam. An attempt is also made to consider the effect of sustained loading and an optimum level of corrosion is proposed up to which maintenance and repair work can be executed at a minimum cost for corroded RC beams.

Study of the Residual Bond Strength between Corroded Steel Bars and Concrete—A Comparison with the Recommendations of Fib Model Code 2010

As is well known, corrosion of steel reinforcement deteriorates the steel–concrete interface and causes concrete cracking, degrading significantly the bond strength. Several experimental studies have investigated the magnitude of residual bond strength due to corrosion, which affects either the function of corrosion-damaged steel bars or the surface crack width in concrete. As a result, linear and exponential correlation relationships have been proposed in order to predict the bond loss due to corrosion. Based on the results of an ongoing experimental campaign on the degradation of bond strength of RC specimens, combined with comparable outcomes from existing literature, this manuscript summarizes a database, comparing with the recommendations of Model Code 2010, to analyze and interpret the corrosion effect on the bond loss and highlights some points that need improvement in the current regulations. As indicated, the density of transverse reinforcement (stirrups spacing) has intense impact on the resulting bond loss due to corrosion. Hence, in order to quantify this aspect, the present manuscript introduces a discretization of confinement levels of RC elements, depending on the stirrups spacing. Based on this, regression analyses of data were conducted to extract fitting curves of bond loss, taking into account the amount of transverse reinforcement and predictive zones of residual bond strength in relationship to either corrosion penetration or surface crack width. Furthermore, the outcomes demonstrate that the corrosion penetration depth is an appropriate assessment tool to correlate the residual bond strength with the corrosion level, whereas the surface crack width on concrete is not yet an effective index, since there is a plethora of factors affecting the crack width. Due to this, more research is needed to improve the current level of knowledge on the surface crack width and link it with the corrosion damage of the steel bar and the residual bond strength due to corrosion.

Experimental dentin adhesives containing calcium orthophosphate particles: Effect on dentin bond strength, micro-permeability and collagen degradation

PurposeTo assess the effect of dicalcium phosphate dihydrate (DCPD) or mineral trioxide aggregate (MTA) particles on the microtensile bond strength (μTBS), micro-permeability and enzymatic activity at the adhesive-dentin interface of experimental dental adhesives. Materials and methodsAn experimental ethanol-based, two-step etch-and-rinse adhesive system was prepared. Four experimental groups were tested, based on the type of particle added: (1) DCPD functionalized with diethylene glycol dimethacrylate (DCPD_DEGDMA), (2) citric acid (DCPD_CA), (3) calcium silicate (MTA) and (4) unfilled (control). All particles were added at 10 wt%. Human third molars had their occlusal enamel removed and dentin surface polished. After acid etching, the adhesives were applied on the dentin surfaces and the teeth were restored with a commercial nanofilled resin composite. The μTBS and micro-permeability were tested after 24 h or 2 months of storage in simulated body fluid (SBF) at 37 °C. Bonded interfaces were observed using scanning electron microcopy (SEM). Gelatinolytic activity at the adhesive interfaces was assessed by in situ zymography at 24 h and 2 months in SBF/37 °C. The results were described as relative florescent units (RFU). μTBS data were analyzed by ANOVA/Games–Howell test. Data from micro-permeability and in situ zymography were analyzed by Kruskal–Wallis/Mann–Whitney test (alpha: 5%). ResultsDifferences in μTBS were found among adhesives (control = MTA > DCPD_CA > DCPD_DEGDMA, p < 0.001), but not between storage times. The control group showed the lowest permeability at both observation periods. Except for DCPD_CA, no significant increases in micro-permeability were observed after 2 months. All groups presented significant reductions in RFU values between 24 h and 2 months. DCPD_DEGDMA (at 24 h) and MTA (at 2 months) presented statistically lower RFU than the control (p < 0.01). ConclusionEvidence of reduced MMP activity was observed at adhesive interfaces with the use of experimental adhesives containing calcium-releasing particles. However, after two months, bond strength and micro-permeability results suggest that interfacial stability was not affected by adhesive formulation.

Mechanical properties and seismic behavior of confined masonry walls in freeze-thaw environment

Previous literatures show that freeze-thaw cycles (FTC) will deteriorate the physical and mechanical properties of masonry materials. The research in this paper focused on the influence of FTC on mechanical properties and seismic performance of confined masonry walls. A series of mortar cubes, brick units and double-shear specimens built of concrete brick and three types of mortar (cement, cement-lime and cement-fly ash) were subjected to testing after rapid freeze-thaw experiment in environmental chamber. Besides, quasi-static tests were performed on four confined masonry wall specimens to investigate their seismic behavior under varying degrees of freeze-thaw damage. The test results indicated that as the number of FTC increased, the compressive strength of mortar and bricks, masonry shear bond strength, load-carrying capacity, displacement ductility, secant stiffness and energy dissipation capacity of confined masonry walls all shown a downward trend. In addition, a prediction model was proposed to obtain the degradation of shear bond strength of masonry subjected to freeze-thaw damage, and could be used in the rapid investigation and non-destructive detection. Moreover, the addition of fly ash was helpful to slow down the deterioration of masonry buildings in freeze-thaw environment.

Hydroxy acids for adhesion to enamel and dentin: Long-term bonding performance and effect on dentin biostability

ObjectivesTo test the demineralization potential, bonding performance, and dentin biostability when using hydroxy acids for etching enamel and dentin. MethodsSurface microhardness, roughness and depth of demineralization were investigated after etching enamel and dentin with 35 % glycolic acid (Gly), tartaric acid (Ta), gluconic acid (Glu), gluconolactone (Gln), or phosphoric acid (Pa) (n = 5/group). Dentin microtensile bond strength (μTBS) after 24 h or 1 year of bonding (n = 8 teeth/group) and enamel shear bond strength (SBS) after 24 h (n = 10 teeth/group) were obtained. In dentin, failure mode was classified as adhesive, cohesive in dentin/resin, or mixed. Dentin biostability was assessed by loss of dry weight and collagen degradation after 30-day incubation (n = 10 beams/group). Statistical analysis consisted of ANOVA with post-hoc Tukey’s HSD, Tukey-Kramer test, Bonferroni correction, and Fisher’s exact tests (α = 0.05). ResultsGly showed better or similar results than Pa for enamel microhardness and dentin roughness, while no significant differences were observed among Ta, Glu, and Gln (p > .05). Hydroxy acids produced significantly shallower demineralization than Pa (p < .05). Gln resulted in the lowest SBS and μTBS, while Gly, Glu, Ta, and Pa showed no significant difference. There was no significant difference in μTBS between 24 h and 1 year of storage. The association between failure mode and etchant was statistically significant after 24 h only (p < .001). Hydroxy acids resulted in higher dentin biostability than Pa (p < .05). ConclusionsGly, Glu and Ta resulted in adequate bonding performance and reduced dentin degradation and are potential alternative etchants to improve long-term stability of adhesive restorations. Clinical significanceThis study supports the potential use of hydroxy acids as alternative etchants when bonding to enamel and dentin and demonstrates that specific acids are more suitable to be used in adhesion since they result in appropriate bond strength and less dentin degradation.

Concrete-steel bond-slip behavior of recycled concrete: Experimental investigation

In order to study the interfacial bond-slip behavior of steel reinforced recycled concrete (SRRC) under cyclic loading, thirteen specimens were designed and tested under cyclic loading and one under monotonic loading. The test results indicated that the average bond strength of SRRC decreased with the increasing replacement ratio of recycled concrete, whereas the bond strength increased with an increase in the concrete cover thickness, the volumetric stirrup ratio, and the strength of recycled concrete. The ultimate bond strength of the cyclically-loaded specimen was significantly (41%) lower than that of the companion monotonically-loaded specimen. The cyclic phenomena also showed that SRRC specimens went through the non-slip phase, initial slip phase, failure phase, bond strength degradation phase and residual phase, with all specimens exhibiting basically the same shape of the bond-slip curve. Additionally, the paper presents the equations that were developed to calculate the characteristic bond strength of SRRC, which were verified based on experimental results.

Bond performance of grouted tendons at elevated temperatures

The bond between tendons and grout is crucial to the performance of bonded post-tensioned concrete structures. To study the bond performance of grouted tendons at elevated temperatures, pull-out tests were conducted on specimens comprising either a mono- or multi-strand tendon located centrally within a grouted duct inside a concrete cylinder, at test temperatures of 20–600°C. It was found that the bond strength deteriorated with a rise in temperature and the degradation of bond strength was more severe than that of other mechanical properties. Three types of failure mode were observed: pull-out, partial splitting and through splitting. The use of a smaller duct could improve the bond strength of specimens failing in pull-out mode. The influence of the strength of the outer concrete was found to be insignificant. Based on the distinct bond behaviour of different failure modes, a bond–slip model was developed by regression of the test results.

Hybrid soft computational approaches for modeling the maximum ultimate bond strength between the corroded steel reinforcement and surrounding concrete

The capacity efficiency of load carrying with the accurate serviceability performances of reinforced concrete (RC) structure is an important aspect, which is mainly dependent on the values of the ultimate bond strength between the corroded steel reinforcements and the surrounding concrete. Therefore, the precise determination of the ultimate bond strength degradation is of paramount importance for maintaining the safety levels of RC structures affected by corrosion. In this regard, hybrid intelligence and machine learning techniques are proposed to build a new framework to predict the ultimate bond strength in between the corroded steel reinforcements and the surrounding concrete. The proposed computational techniques include the multilayer perceptron (MLP), the radial basis function neural network and the genetic expression programming methods. In addition to that, the Levenberg–Marquardt (LM) deterministic approach and two meta-heuristic optimization approaches, namely the artificial bee colony algorithm and the particle swarm optimization algorithm, are employed in order to guarantee an optimum selection of the hyper-parameters of the proposed techniques. The latter were implemented based on an experimental published database consisted of 218 experimental tests, which cover various factors related to the ultimate bond strength, such as compressive strength of the concrete, concrete cover, the type steel, steel bar diameter, length of the bond and the level of corrosion. Based on their performance evaluation through several statistical assessment tools, the proposed models were shown to predict the ultimate bond strength accurately; outperforming the existing hybrid artificial intelligence models developed based on the same collected database. More precisely, the MLP-LM model was, by far, the best model with a determination coefficient (R2) as high as 0.97 and 0.96 for the training and the overall data, respectively.

An adaptive coupling method of state-based peridynamics theory and finite element method for modeling progressive failure process in cohesive materials

In this study, an adaptive coupling method is proposed for the combination of the state-based peridynamics theory (PD) and the classical finite element method (FEM). The non-local PD theory is used for dealing with localized cracking process while the FEM is adopted for modeling elastic (or plastic) problems without localization. The evolving boundary between cracking domain and the elastic or plastic domain without localization is taken into account. A new bond damage model is implemented into the ordinary state-based PD theory, by considering the progressive degradation of bond strength and residual strength. The proposed coupling method and bond damage model are implemented in MATLAB framework. The accuracy of the PD-FEM coupling method is verified by the analytical solutions in elastic cases. The efficiency of the new bond damage model implemented in the adaptive PD-FEM coupling method for modeling the progressive failure process in cohesive materials is clearly validated through a series of representative laboratory tests on concrete structures.

Bond Strength Assessment of Concrete-Corroded Rebar Interface Using Artificial Neutral Network

Bond strength assessment is important for reinforced concrete structures with rebar corrosion since the bond degradation can threaten the structural safety. In this study, to assess the bond strength in concrete-corroded rebar interface, one of the machine learning techniques, artificial neutral network (ANN), was utilized for the application. From existing literature, data related to the bond strength of concrete and corroded rebar were collected. The ANN model was applied to understand the factors on bond property degradation. For the input in the ANN model, the following factors were considered the relative bond strength: (1) corrosion level; (2) crack width; (3) cover-to-diameter ratio; and (4) concrete strength. For the cases with confinement (stirrups), (5) the diameter/stirrups spacing ratio was also considered. The assessment was conducted from input with single parameter to multiple parameters. The scaled feed-forward multi-layer perception ANN model with the error back-propagation algorithm of gradient descent and momentum was found to match the experimental and computed results. The correlation of each parameter to the bond strength degradation was clarified. In cases without confinement, the relative importance was (1) &gt; (2) &gt; (4) &gt; (3), while it was (2) &gt; (1) &gt; (3) &gt; (5) &gt; (4) for the cases with confinement.

Experimental study on fatigue performance of RC beams strengthened with CFRP under variable amplitude overload and hot-wet environment

Highway reinforced concrete (RC) bridges are generally served under hot-wet environment and vehicle overload in south China, which will cause great fatigue damage to the bridge structures. To discuss the fatigue damage mechanism, a fatigue experimental method of RC bridge structures under the coupling action of variable amplitude overload and hot-wet environment was proposed in this paper. Fatigue tests of 38 RC beams strengthened with carbon fiber reinforced polymer (CFRP) were carried out with the experimental method. Fatigue performance and failure mechanism of the beams were discussed. Results showed that bond strength degradation of CFRP-concrete interface under hot-wet environment, early yielding and rupture of tensile rebars under overload, caused the loss of flexural stiffness and fatigue performance of the strengthened beams. Fatigue lives under variable amplitude overload of the strengthened beams were predicted effectively with a proposed modified Miner rule. Both temperature and relative humidity affected the fatigue lives and fatigue limits, while high-temperature and high-humidity environment led to severe deterioration of fatigue performance of the strengthened beams.

Bond behavior between recycled aggregate concrete and deformed rebar after Freeze-thaw damage

In this study, the internal cracks and residual deformation, as well as the damage mechanism of both natural aggregate concrete (NAC) and recycled aggregate concrete (RAC) after different freeze–thaw cycles (0, 50, 100, 150, 200, 250, and 300) were firstly investigated. After that, 51 axial pull-out tests were carried out to analyze the influence of two comprehensive orthogonal parameters, the replacement percentage of recycled coarse aggregate (0, 50%, and 100%) and the number of freeze–thaw cycles (0, 50, 100, 150, 200, 250, and 300) on the peak bond strength and peak slip between RAC and deformed rebar. A bond strength degradation model with splitting tensile strength as the damage factor was established. The “softened inner layer + elastic outer cylinder” theory was modified, and the theoretical calculation equations of peak bond strength and yield bond strength between deformed rebar and RAC after freeze–thaw damage were also proposed. The results showed that as the number of freeze–thaw cycles increased, the bond behavior between RAC and deformed rebar gradually degenerated, the peak bond strength decreased gradually, while the peak slip decreased first and subsequently increased. The replacement percentage of recycled coarse aggregate affected the bond behavior differently for different freeze–thaw cycles. When the number of freeze–thaw cycles was small, the bond strength between RAC and deformed rebar was poorer than that between NAC with the same compressive strength and deformed rebar. However, with the increase of the number of freeze–thaw cycles, the bond strength between RAC and deformed rebar was superior to that between NAC and deformed rebar. The fitting and theoretical equations of bond strength proposed in this study were in good agreement with the experimental results.

Cyclic bond property of steel reinforced recycled concrete (SRRC) composite structure

For the composite structures consisting of the steel profile and recycled concrete, the interfacial bond property between steel and concrete is the most critical factor for the collaborative work. In order to study the interfacial bond property of steel reinforced recycled concrete (SRRC) structures, seven SRRC specimens were fabricated and then tested cyclically. The influences of replacement ratio of recycled aggregate and compressive strength of recycled concrete on the bond behavior of this combination were assessed by looking at failure patterns, hysteretic performance, backbone curves, characteristic loads and corresponding slip, bond strength degradation, and degradation mechanism. Test results showed that the replacement ratio of recycled aggregate dominates the onset of slip between steel and recycled concrete. The obvious pinching phenomenon appears on the hysteresis curves, indicating apparent slip characteristics between the steel profile and recycled concrete. As the chemical cementing force gradually loses effectiveness, the bond strength mainly relies on the friction to maintain the stress balance after the interfacial bond layer gradually crushes. Based on the experimental results, a simplified bond-slip model was proposed and divided into four parts, i.e. intact, hardening, degradation and failure stages, and the degradation mechanism corresponding to each segment was then analyzed in detail.

Influence of acidic monomer concentration and application mode on the bond strength of experimental adhesives

The aim of this research was to evaluate the influence of MDP (10-methacryloyloxydecyl dihydrogen phosphate) concentration and application mode of experimental adhesives on microshear bond strength (μSBS) to dentin after storage in distilled water at 37°C for 24h and 6 months. Five experimental adhesives were prepared with: CQ, DABE, BHT, ethanol, HEMA, TEGDMA, Bis-EMA, UDMA, and Bis-GMA. Concentrations of 0 wt%, 3 wt%, 9 wt%, 12 wt% or 15 wt% of MDP were added to their composition. The adhesives were applied to flat dentin surfaces in etch-and-rinse or self-etching modes. Cylindrical molds filled with light-cured composite resin were placed above the dentin. The specimens were stored in distilled water at 37oC for 24h or 6 months and submitted to μSBS testing. The adhesives were also submitted to pH analysis. The data were analyzed by one-way ANOVA, three-way ANOVA and Tukey's test (α = 5%). All the adhesives used in the etch-and-rinse mode showed significantly higher bond strength than the adhesives applied in the self-etching approach. The 9 wt% adhesive showed the highest bond strength values, and 3 wt% was most stable after storage. A strong negative correlation between MDP concentration and pH was observed. It was concluded that the formulations with low concentrations of MDP (up to 9 wt%) showed better results for bond strength and bond strength degradation over time.

Effects of elevated temperatures on mechanical behavior of epoxy adhesives and CFRP-steel hybrid joints

High environmental temperatures can significantly degrade the mechanical behavior of CFRP-steel composites, due to the reduced bond performance of epoxy adhesives. Here, we systematically investigate the effects of elevated temperatures on the mechanical behavior of epoxy adhesives and CFRP-steel hybrid joints. First, the glass transition behavior and mechanical properties of four distinct epoxy adhesives subjected to elevated temperatures were studied via dynamic mechanical analysis (DMA) and tensile tests. The failure process of CFRP-steel double-lap joints was subsequently investigated under different elevated temperatures. Digital image correlation (DIC) technique was utilized to capture the full-field strains on the specimens during the testing. The results indicate that adhesive Araldite 2014 possesses the highest glass transition temperature, followed by adhesive J133. However, adhesive J133 possesses the highest tensile strength and toughness under all testing temperatures and forms the most robust bonding between CFRP and steel at these temperatures. The bond strength is reduced by over 50% at 70 °C compared with that at room temperature, and the degradation of bond strength is correlated with that of the tensile strength of the adhesives. We also find that it is more appropriate to use Tg,o as an indicator to determine the working temperature limit of epoxy adhesives.

Risk of failure in existing RC balcony and strength verification under degradation phenomena

In the present paper, the safety conditions of reinforced concrete (RC) balconies subject to degradation phenomena caused by carbonation, presence of chlorides or water infiltration were examined. After a brief review of the typical damages of balconies occurring with detachments of plaster and bricks expulsion, some cases of collapses of balconies recently occurred were presented.Therefore, a calculation model was proposed for a hand verification of the flexural and shear strength of existing corroded T beams cast in place of lightened RC orthotropic slabs forming the balcony and for the calculus of deflection including slippage of steel bars. Diffused and pitting corrosion on steel bars, compressive concrete strength degradation, and concrete bond strength degradation are included in the model. This approach is simple and can be applied based on the experimental information available (carbonation test, chloride content, measurement of the pitting in the bar, a gravimetric method for general corrosion) or by utilizing analytical expressions calibrated on knowledge of the corrosion current intensity determined by linear polarization resistance measurement (LPR).

Effects of sodium hypochlorite as dentin deproteinizing agent and aging media on bond strength of two conventional adhesives.

This study evaluated the effect of 10% sodium hypochlorite (NaOCl) as deproteinizing agent and storage media on bond strength (BS) of two etch-and-rinse adhesive systems to dentin. Twenty-eight sound extracted human third molars were divided in four groups (n = 7), according to dentin treatment (conventional etching or etching followed by 10% NaOCl application) and adhesive systems (GB-Gluma 2Bond and OS-One-Step). After dentin treatments and adhesive application, a composite block was built-up on dentin surface and teeth were serially sectioned to obtain bonded sticks specimens. The sticks were submitted to three aging conditions: (24H) 24 hr in water (immediate), (SH) 3 hr of NaOCl accelerated-aging or (1Y) 1 year of water storage. Afterward, submitted to microtensile bond strength test (μTBS), failure modes and adhesive interfaces analyzes. Data were analyzed by two-way analysis of variance (ANOVA) and Tukey's test (α = .05). Dentin deproteinization before bonding significantly reduced μTBS for GB-treated group (p < .05), regardless the aging conditions. Water storage for 1 year (1Y) and NaOCl accelerated-aging (SH) decreased μTBS for both adhesives. Yet, the groups stored in NaOCl (SH) exhibited the lowest BS results (p < .05). Bond strength of deproteinized dentin was dependent on the adhesive system composition and NaOCl accelerated-aging promoted decreased bond strength and further degradation than water storage for 1 year.