Cement Interface Research Articles

The Effectiveness of Various Functional Monomers in Self-adhesive Resin Cements on Prosthetic Materials.

ABSTRACTAim:This study examined the influence of various functional monomers in two self-adhesive resin cements (SACs) on prosthetic materials.Materials and Methods:Base metal alloy, lithium disilicate glass-ceramic, and zirconia were used as bonding materials. Silicon carbide paper was used to polish the specimens. Two self-adhesive resin cements (Panavia SA luting multi, PAM, and Maxcem elite chroma, MAC) were used. Ten specimens for each material were produced and resin cements were bonded to each material. The specimens were stored in 37°C distilled water in an incubator for 24 hours. A universal testing machine was used to measure the shear bond strength. The data were statistically examined using one-way ANOVA and Tukey’s test.Results:In all prosthetic materials, PAM had the highest bond strength. In lithium disilicate glass-ceramic, the lowest bond strength was found with MAC.Conclusion:The self-adhesive resin cement (PAM) containing 10-MDP monomer and long carbon-chain silane was performed the greatest outcome in the shear bond strength on the prosthetic materials and self-adhesive resin cement interface.

The role of aggregate and cement paste in the deterioration of the transitional interface zone of pervious concrete during freeze-thaw cycles

Improving the performance of the cement matrix is an effective method to enhance the freeze-thaw (F-T) damage resistance of pervious concrete. However, the interfacial transition zone (ITZ) is the weakest component. The purpose of this paper is to evaluate the effect of ITZ on the deterioration of pervious concrete under F-T circumstances. The evolution of the compressive strength of samples under water and salt F-T conditions was obtained by uniaxial compression tests. Additionally, the development of the ultrasonic velocities and the relative dynamic modulus of elasticity were examined. Changes in the microstructure and the pore structure were also continuously monitored. The results demonstrate that as the number of F-T cycles rises, compressive strength and dynamic elastic modulus diminish, and the deterioration of samples in 3% NaCl solution is more severe than that in water. Within 100 F-T cycles, cement paste samples with the identical w/c as pervious concrete showed no discernible strength deterioration, and detrimental porosity did not alter considerably. Scanning electron microscopy (SEM) results showed that the performance difference between aggregate and ITZ and the expansion stress lead to debonding at the interface of aggregate and cement, which is the primary culprit for the worsening of pervious concrete under F-T conditions. This work serves as a reference for the deterioration mechanism and durability enhancement of pervious concrete under F-T circumstances.

Bone Cements Used for Hip Prosthesis Fixation: The Influence of the Handling Procedures on Functional Properties Observed during In Vitro Study.

The failure of hip prostheses is a problem that requires further investigation and analysis. Although total hip replacement is an extremely successful operation, the number of revision surgeries needed after this procedure is expected to continue to increase due to issues with both bone cement types and cementation techniques (depending on the producer). To conduct a comparative analysis, as a surgeon prepared the bone cement and introduced it in the body, this study’s team of researchers prepared three types of commercial bone cements with the samples mixed and placed them in specimens, following the timeline of the surgery. In order to evaluate the factors that influenced the chemical composition and structure of each bone cement sample under specific intraoperative conditions, analyses of the handling properties, mechanical properties, structure, and composition were carried out. The results show that poor handling can impede prosthesis–cement interface efficacy over time. Therefore, it is recommended that manual mixing be avoided as much as possible, as the manual preparation of the cement can sometimes lead to structural unevenness.

Cement Sheath Integrity in Anisotropic Shale Formations: A Numerical Investigation

Cement sheath should provide zonal isolation and structural support during the full life cycle of a well. However, achieving long-term cement sheath integrity under complex geological and operational conditions, especially in bedding shales characterized by strong anisotropy, is still a great challenge. Thus, to better understand the effects of the anisotropy of shales on cement sheath integrity, this paper developed a 3D coupled thermal-hydro-mechanical model of the formation-cement-casing system. Stress generation and evolution within cement sheath are also considered in the modeling. The model is validated against analytical solutions and physical experimental results. Then, sensitivity analyses were performed to investigate the initial stress of cement sheath and shale anisotropy on cement sheath integrity. The results show that the anisotropy of Young’s modulus has a greater influence on cement sheath integrity compared to the anisotropy of Poisson’s ratio. Debonding between the cement sheath and formation can be easily generated due to the shale’s high anisotropy of Young’s modulus. The aperture of the microannulus along the cement interface varies with the angle between the wellbore axis and the bedding plane. The minimum microannulus is developed where the wellbore is parallel to the shale’s bedding planes. The results also indicate that initial stress generated in the cement sheath after its hardening is beneficial for the integrity of the cement-formation interface.

Experimental study on the shear behavior of frozen cemented sand-structure interface

The shear behavior of the interface between frozen cemented soil and structure is important for analyses of soil-structure interaction and foundation design involving cement grouting and ground freezing. This paper investigated the shear behavior of frozen cemented sand-structure interface. Direct shear experiments were conducted on the frozen sand- and frozen cemented sand-structure interface specimens at various sub-freezing temperatures and normal stresses. Experimental results, including shear stress-displacement curves, the adfreeze and residual strengths, and their differences between the frozen sand- and frozen cemented sand-structure interfaces, were presented and analyzed. The shear stress-displacement relationships of both interfaces display a wave pattern, and the adfreeze and residual strengths of the frozen cemented sand-structure interface were found to decrease significantly when compared with the one without cementation. On average, the adfreeze strength of the frozen cemented sand-structure interface decreases by 47% and the residual strength by 19% compared to the case without cement. As the temperature drops from −2 °C to −14 °C, the peak interface cohesion of the frozen sand case increases by 393%, while that of the frozen cemented sand case rises by 115%. Empirical formulas based on the Mohr-Coulomb model between the strengths and testing parameters, including temperature and normal stress, were proposed for both interfaces. The findings from this study help understand the impact of cement grouting on the shear behavior of frozen sand-structure interface and are significant for practices such as ground construction and foundation engineering when cement grouting is involved in ground freezing.

Damage mechanism of pier concrete subjected to combined compressive stress, freeze-thaw, and salt attacks in saline soil

This study experimentally investigates the damage mechanism of pier concrete under the combined action of axial compressive stress (CS), freeze–thaw (FT) cycles, and salt attacks (SA). An indoor accelerated corrosion test of pier concrete under the combined action of CS, FT, and SA was conducted based on field investigations of concrete corrosion of piers in the saline soil of Xinjiang province in China. The experimental results of macro and micro analyses showed that the durability degradation of the pier concrete could be attributed to the damage to the cement slurry, aggregates, interface areas, and pore structure. A new delamination damage model was established to describe the mechanism of the combined damage, including the deterioration of the mortar layer, the generation of microcracks in the interface zone, the deposition of corrosion products, and crack development. The quantitative assessment of the durability degradation of the pier concrete was more accurate when the mass loss (ML) and relative dynamic elastic modulus (RDEM) were considered. These unique findings provide an important reference for the design and durability evaluation of pier concrete in saline soils.

Geopolymer and ordinary Portland cement interface analyzed by micro-Raman and SEM

ABSTRACT Geopolymers are a class of material that could potentially be used for sealing and repair of damaged concrete structures. This application is important for both decommissioning activities and standard industrial applications. The purpose of this article is to investigate the interface between ordinary Portland cement and geopolymer. The surface microstructure of the cement is investigated by SEM, EDX, and micro-Raman after embedding in geopolymer or immersion in the activation solution of a geopolymer for various durations. It is found that immersion in the solution induces a dendritic carbonation profile into the cement structure following the CSH gel. On the contrary, embedding in the geopolymer creates a dense, impermeable interface with a thickness of a few micrometers. This interface is found to be dense and brittle and it decreases the permeability of the surface, preventing the penetration of silicates into the cement structure. However, this brittle interface is sensitive to dehydration and can rupture under intense drying. This phenomenon can be utilized to separate the geopolymer and cement but is concerning if the integrity of the material must be guaranteed under extreme conditions.

Cyclic Shear Behavior of Warm and Ice-Rich Frozen Cemented Sand-Structure Interface

Cyclic Shear Behavior of Warm and Ice-Rich Frozen Cemented Sand-Structure Interface

IMPROVING MECHANICAL PROPERTIES OF OIL WELL CEMENT USING POLYPROPYLENE FIBERS AND EVALUATING A NEW LABORATORY METHOD FOR MEASURING THE CASING CEMENT BONDING STRENGTH

The main objective of this study is to enhance the poor performance of oil well cement in terms of mechanical properties by using pure polypropylene fibers. Polypropylene fibers were added in increasing concentrations from 0 to 0.1%, 0.3%, 0.5%, 0.7%, and 0.9% by weight of cement (BWOC). Rheological parameters, density, fluid loss, permeability, porosity, compressive strength, tensile strength, and flexural strength were all tested. A new method for measuring the tensile strength of cement samples in the presence of a casing is also evaluated in this research. In addition, the interfacial bonding shear strength, which represents the strength of cement adhesion to the casing, was measured using a new laboratory procedure. The influence of adding polypropylene fibers on rheology, density, and fluid loss can be ignored, according to the results of the experiments. The permeability and porosity of cement samples increased as the proportion of polypropylene fibers increased, according to the findings. Further, an increase in polypropylene fibers concentration up to 0.3% BWOC led to improving the mechanical properties at different curing times. The bonding strength of the casing cement interface improved with increasing polypropylene fibers concentration up to 0.5% BWOC.

Crack resistance of a noble green hydrophobic antimicrobial sealing coating film against environmental corrosion applied on the steel-cement interface for power insulators.

Due to their great load-bearing capabilities, steel–cement interface structures are commonly employed in construction projects, and power utilities including electric insulators. The service life of the steel–cement interface is always decreasing owing to fracture propagation in the cement helped by steel corrosion. In this paper, a noble crack-resistant solution for steel–cement interfaces utilized in hostile outdoor environments is proposed. A Ce-rich, homogeneous, and thick hydrophobic sealing coating (HSC) is developed on the steel–cement interface after 60 minutes of immersion in a 60 000 ppm CeCl3·7H2O sealing coating solution. The specimens treated with optimized HSC film demonstrate fissure filling, lowest corrosion current (Icorr) 2.3 × 10−7 A cm−2, maximum hardness (109 Hv), oxide-jacking resistance (40 years), hydrophobic characteristics, carbonation resistance, and bacterial corrosion resistance, resulting in a crack-free steel–cement interface. This work will pave the way for a new branch of environmentally acceptable coatings for the construction and power industries.

Comparative evaluation of bond strength of resin cements with and without 10-methacryloyloxydecyl dihydrogen phosphate (mdp) to zirconia and effect of thermocycling on bond strength - An in vitro study.

BackgroundTo compare bond strength of resin cements with and without 10-Methacryloyloxydecyl Dihydrogen Phosphate (MDP) to zirconia and evaluate effect of thermocycling on bond strength. Material and MethodsStandardised test specimens were fabricated as per ADA specification 131. Each Zirconia specimen was mounted in autopolymerzing acrylic resin material. The specimens were divided into 2 groups: Group 1 – specimens bonded with resin cement containing 10-MDP and Group II - specimens bonded with resin cement without 10-MDP. Forty samples of resin cement cylinders were prepared with dimensions of 6mm height and 4mm diameter in line with ADA specification 27 were cured onto the zirconia surface of 10mm x10mm x5mm using customised moulds. Specimens from each cement group were further divided into 2 subgroups: Subgroup A – Specimens that were not thermocycled and Subgroup B – Specimens that were thermocycled. Specimens were then subjected to tensile bond testing by using a Universal testing machine, the data were analysed using independent sample t test for bond strength and paired t test for effect of thermocycling. Statistical analysis used: Data was subjected to normalcy test (Shapiro-wilk test). Data showed normal distribution. Hence parametric test paired t test were applied. ResultsPaired t test revealed that the thermocycling affected the bond strength to zirconia. The highest bond strength was achieved for the resin cement with 10-MDP before thermocycling, whereas the lowest bond strength values were recorded for resin cement without 10-MDP after thermocycling. ConclusionsResin cement with 10-MDP showed superior bond strength to Zirconia than resin cement without 10-MDP. Adhesive failure was predominant at Zirconia and resin cement interface. Thermocycling had a significant effect on the bond strength of resin cements to zirconia, showing decreased bond strength. Key words:10-MDP, Tensile Strength, Zirconia.

Assessment of the Shear Bond Strength of Composite Resin to Fresh Amalgam Using Different Adhesion Protocols: An In Vitro Study

Introduction: This study was conducted to evaluate and compare the effect of using three adhesive systems on the shear bond strength between composite resin and fresh amalgam. Materials and Methods: Amalgam samples were assigned into three groups according to the adhesive systems being used prior to the composite resin application. Group A (n = 10): universal self-etch bonding system (Single Bond Universal Adhesive, 3M, Neuss, Germany) was applied and light cured. Group B (n = 10): universal self-etch bonding was applied and light cured, followed by a thin layer of nanohybrid flowable composite (Tetric N-Flow, Ivoclar Vivadent, Liechtenstein), then light cured. Group C (n = 10): self-adhesive dual-cure luting resin cement (Calibra Universal, Dentsply Sirona, Charlotte, NC) was applied in equal quantity for each sample over amalgam surface. Composite resin was then applied by plastic instrument in a single increment to the height of the hole (2 mm), then celluloid strip was placed and light cured. After thermocycling, a shear bond test was performed. Results: Resin luting cement interface showed the higher significant bond strength, followed by universal bonding agent − flowable composite interface. The universal bonding interface group yielded the lowest results. Conclusion: The application of self-adhesive dual-cure luting resin cement resulted in significant increase in bond strength between composite resin and fresh amalgam.

Synergy of reduced graphene oxide and metal oxides improves the power factor of thermoelectric cement matrix composites

Thermoelectric cement, a functional material that realizes the mutual conversion of thermal and electrical energy, has wide application prospects in energy harvesting and urban heat island effect mitigation. In this article, metal oxides and reduced graphene oxide (RGO) were added through ethanol liquid-phase mixing and pre-dispersion processes to the cement-based composites to enhance the thermoelectric properties. The addition of metal oxide increases the metal oxide/cement interface (metal oxide to cement interface, metal oxide to RGO interface, etc.). The presence of high-density interfaces hinders the carrier motion and leads to carrier scattering at the interfaces, which enhances the Seebeck effect of cement matrix composites. When the TiO2 content is 10.0 wt%, the RGO cement matrix composite achieved a power factor (PF) of 1.23 μWm−1 K−2, which was 10 times higher than before the addition. This study is a novel idea for further improving the thermoelectric properties of cementitious composites and promoting their practical applications.

Does Additive Pressurized Carbon Dioxide Lavage Improve Cement Penetration and Bond Strength in Cemented Arthroplasty?

The modern cementing technique in cemented arthroplasty is a highly standardized and, therefore, safe procedure. Nevertheless, aseptic loosening is still the main reason for revision after cemented total knee or cemented total hip arthroplasty. To investigate whether an additional carbon dioxide lavage after a high-pressure pulsatile saline lavage has a positive effect on the bone–cement interface or cement penetration, we set up a standardized laboratory experiment with 28 human femoral heads. After a standardized cleaning procedure, the test implants were cemented onto the cancellous bone. Subsequently, the maximum failure load of the bone–cement interface was determined using a material testing machine to pull off the implant, and the cement penetration was determined using computed tomography. Neither the maximum failure load nor cement penetration into the cancellous bone revealed significant differences between the groups. In conclusion, according to our experiments, the additive use of the carbon dioxide lavage after the high-pressure pulsatile lavage has no additional benefit for the cleaning of the cancellous bone and, therefore, cannot be recommended without restrictions.

Changes in the immitance spectra of the cement paste in the initial period of hardening

The paper analyzes changes in the impedance and admittance spectra of the cement slurry during hardening. The spectra were measured in the frequency range from 20 Hz to 2 MHz on a precision RLC meter Agilent E4890A using a homemade capacitor measuring cell. The studies in order to establish the optimal equivalent electrical circuits describing the transformation of the electrophysical properties of the cement slurry and interface phenomena in the near-electrode layer of the measuring cell from the time of hardening were carried out. The sensitivity of the parameters of equivalent circuits to different stages of cement slurry hardening has been established.

Effects of silane treatment on the bond between steel fibres and mortar

The ability of fibres to resist crack growth in fibre-reinforced concrete can be significantly influenced by the fibre–matrix bond. This investigation reveals surface treatment of fibres as a viable technique for developing a uniform bond along the fibre–cement interface to resist growth of microcracks and thereby complement the physical restraint against pull-out provided by fibres’ shape and friction. Previous reports have shown effective chemical treatment of glass, carbon and polypropylene fibres. However, research into chemical surface treatment processes for steel fibres, the most common in concrete, is scarce and focused on corrosion and dispersion, rather than the fibre–matrix bond. Here, a silane treatment technique is proposed to strengthen the steel fibre–cementitious matrix bond. Surface energy measurements and X-ray photoelectron spectroscopy demonstrate the effectiveness of this treatment. Fibre pull-out tests conducted on silane-treated fibres show an apparent increase in pull-out energy, accompanied by a delay in reaching the peak load, compared with untreated fibres, suggesting increased resistance to crack initiation and growth. Furthermore, the results indicate improved flexural strength and direct tensile strength of mortar reinforced with silane-treated fibres compared with untreated fibres. The improvements are further corroborated by results from restrained drying shrinkage and volume of permeable voids.

Cement debonding behaviors of the various tibial components of the ATTUNE knee system and its predecessors: Is a cement-in-cement revision an alternative?

BackgroundAseptic loosening remains one of the most common causes of revision of the tibial component for total knee arthroplasty. A stable bond between implant and cement is essential for appropriate long-term results. The aim of our in vitro study was to investigate the maximum failure load of tibial ATTUNE prosthesis design alternatives compared with a previous design. In addition, cement-in-cement revision was considered as a potential strategy after tibial component debonding. MethodsThe experimental investigations of the maximum failure load of the implant–cement interface were performed under optimal conditions, without potential contamination. We compared the designs of the tibial components of the ATTUNE, ATTUNE S+ and P.F.C. Sigma. In addition, we investigated the cement-in-cement revision for the ATTUNE knee system replacing it with an ATTUNE S+. ResultsThe maximum failure load showed no significant difference between P.F.C. Sigma and ATTUNE groups (P = 0.087), but there was a significant difference between the P.F.C. Sigma and the ATTUNE S+ groups (P < 0.001). The analysis also showed a significant difference (P < 0.001) between the ATTUNE and the ATTUNE S+ groups for the maximum failure load. The ATTUNE S+ cement-in-cement revision group showed a significant higher failure load (P < 0.001) compared with the P.F.C. Sigma and ATTUNE groups. No significant differences (P = 1.000) were found between the ATTUNE S+ cement-in-cement and ATTUNE S+ group. ConclusionBased on these results, we found no design-specific evidence of increased debonding risk with the ATTUNE and ATTUNE S+ components compared with the P.F.C Sigma. Furthermore, the cement-in-cement revision seems to be an alternative for the revision surgery.

Influence of free electron charge and free extra framework anions in calcium aluminate@ rGO (CA@ rGO) cement composites with enhanced dielectric and electrochemical properties

Nowadays, the metal oxide-based composites loaded with reduced graphene oxide (rGO) nano sheets are believed to enhance both the electrochemical and dielectric properties. In this study, therefore, the effect of rGO loading contents on the calcium aluminate (CA), namely CA@ rGO, cement composites with high dielectric and electrochemical properties is presented. CA@ rGO composites were successfully synthesized via a simple direct mixing of CA cement with various contents of graphene oxide (GO) precursors followed by a conventional thermal reduction method. Based on XRD and Raman spectroscopy results, all prepared CA@ rGO composites clearly confirmed both the structure of the pristine CA cement as well as the complete conversion of GO precursors to rGO after thermal reduction, and the existence of rGO nano sheets on the surface of CA@ rGO composites. The impedance value results revealed that the enhancement of a high dielectric constant was achieved in the CA@ rGO composites due to both typical interface polarization and the micro-capacitor of CA cement and rGO nano sheets. Meanwhile, the prepared CA@ rGO-4 composite electrode exhibited the highest of electrochemical double-layer capacitive behavior with the specific capacitance (Csc) value of 79.33 F g−1 at 0.2 A g−1. The enhanced super-capacitive performance of CA@ rGO composite can be improved by the synergistic effect of free electron transfer and electron diffusion between the CA cement interface and rGO nano sheets.

Comparative Evaluation of Two Glass Polyalkenoate Cements: An In Vivo Pilot Study Using a Sheep Model.

Poly(methyl methacrylate) (PMMA) is used to manage bone loss in revision total knee arthroplasty (rTKA). However, the application of PMMA has been associated with complications such as volumetric shrinkage, necrosis, wear debris, and loosening. Glass polyalkenoate cements (GPCs) have potential bone cementation applications. Unlike PMMA, GPC does not undergo volumetric shrinkage, adheres chemically to bone, and does not undergo an exothermic setting reaction. In this study, two different compositions of GPCs (GPCA and GPCB), based on the patented glass system SiO2-CaO-SrO-P2O5-Ta2O5, were investigated. Working and setting times, pH, ion release, compressive strength, and cytotoxicity of each composition were assessed, and based on the results of these tests, three sets of samples from GPCA were implanted into the distal femur and proximal tibia of three sheep (alongside PMMA as control). Clinical CT scans and micro-CT images obtained at 0, 6, and 12 weeks revealed the varied radiological responses of sheep bone to GPCA. One GPCA sample (implanted in the sheep for 12 weeks) was characterized with no bone resorption. Furthermore, a continuous bone–cement interface was observed in the CT images of this sample. The other implanted GPCA showed a thin radiolucent border at six weeks, indicating some bone resorption occurred. The third sample showed extensive bone resorption at both six and 12 weeks. Possible speculative factors that might be involved in the varied response can be: excessive Zn2+ ion release, low pH, mixing variability, and difficulty in inserting the samples into different parts of the sheep bone.

A Parametric Study for Radial Cracking in Cement Under Different Loading Events Based on the Stress Intensity Factor

AbstractCement is one of the primary barriers in a wellbore and critical to well integrity. Radial cracking is a pervasive failure mode in cement due to the temperature and pressure variation during drilling, completion, or production. This work presents a comprehensive analysis of radial cracking in cement under various loading events. The proposed model estimates the stress intensity factor and fracture surface displacement as indicators for crack propagation and opening, respectively, through a distributed dislocation technique. Three types of radial cracks, divided by their tips terminating at the casing–cement interface, inside cement, or at the cement–formation interface, are considered. Based on this model, we conduct a parametric study for radial cracking under typical loading events such as steam injection, CO2 injection, and high-pressure and high-temperature (HPHT) drilling. Results indicate that the crack near the casing–cement interface has an increased risk for steam injection and HPHT drilling, while all three types of radial cracks are destructive during CO2 injection. The thermal expansion coefficient of cement is a significant parameter for steam and CO2 injection wells. The fluid pressure and the cement’s thickness are crucial to radial cracking under HPHT conditions. Stiffer cement could promote crack opening for steam injection but prohibit the crack deformation for CO2 injection or HPHT wells. Thicker cement would accelerate radial cracking under the three loading events. These findings are helpful in designing cement to maintain long-term integrity.