Tube Specimens Research Articles

Abstract B15: BRCA haploinsufficiency promotes gluconeogenesis in fallopian tube epithelial cells

Abstract Introduction: High-grade serous ovarian cancer (HGSC) is one of the deadliest gynecologic malignancies due to presentation at advanced stages and the development of chemotherapy resistance. The recent discovery that HGSC arises from fallopian tube epithelia (FTE) and the analysis results obtained from TCGA study are helping in understanding the genes involved in the progression of the disease. HGSC is genetically unstable due to the loss of function mutations in BRCA1, BRCA2, PALB2, ATM, and RAD51 genes involved in DNA damage response. These genes also regulate cellular metabolism, antioxidant, and detoxification responses. Preliminary data show that phase II antioxidant enzymes are significantly reduced in HGSC and there is an increase in reactive oxygen species (ROS) in cells harboring p53 and BRCA1 mutations in precursor lesions of FTE and HGSC. We also observed differential mRNA expression of PCK1 and PCK2, GLUT1 genes involved in gluconeogenesis and glycolysis. Mitochondria are one of the major organelles for the production of ROS, and it is a well-known fact that metabolism is drastically changed in cancer cells compared to normal cells. Our aim was to determine the metabolic and fuel dependency in preneoplastic transformed cells, characterize the mitochondrial phenotype, and link these dependencies to transformation in FTE. Methods: Fallopian tube specimens were obtained from the Biospecimen Shared Resources Core at SCCC. Patients undergoing risk reduction surgery were consent and FTE cells were obtained from BRCA and non-BRCA. Preneoplastic cell lines were then generated by hTERT, p53 mutation (R175H), and HPVE7. To mimic the genetic changes of in vivo HGSC, oncogenes CCNE1 and PIK3CA-H1047R were then overexpressed (OE) in these immortalized cell lines. Xenografts were generated from the transformed FTE cells lines. Agilent Seahorse assays were used to study the fuel dependency, oxidative phosphorylation, and glycolysis. Results: FTE-BRCA1 and FTE-BRCA2 cells showed differences in both glycolytic and oxidative metabolism depending on the oncogenic type. The transformed cells had lower oxidative metabolism and there was also discrepancy in the dependency of metabolites utilized by these cell lines for energy. As seen by mRNA, FTE-BRCA cells had more PCK2 protein and were characterized by higher metabolic rates; these observations were augmented in the presence of PIK3CA-H1047R. However, these FTE preneoplastic and oncogene transformed cells showed no difference in their mitochondrial mass or membrane potential. Conclusion: FTE-BRCA mutant cells utilize glycolysis or gluconeogenesis pathways to overcome metabolic stress depending on which oncogene is driving carcinogenesis. Further work is required to elucidate the mechanism of PCK2 and BRCA link in ovarian cancer carcinogenesis. Citation Format: Iru Paudel, Ramlogan Sowamber, Leah Dodds, Alex Sanchez, Marilyn Huang, Matthew Schlumbrecht, Brian Slomovitz, Sophia George. BRCA haploinsufficiency promotes gluconeogenesis in fallopian tube epithelial cells [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research; 2019 Sep 13-16, 2019; Atlanta, GA. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(13_Suppl):Abstract nr B15.

Tests and numerical simulation of rectangular RACFST stub columns under concentric compression

Tests and numerical simulation of rectangular recycled aggregate concrete filled steel tube (RACFST) stub columns under concentric compression are carried out. Eighteen specimens, including 12 RACFST specimens and 6 concrete filled steel tube (CFST) specimens as reference, with varied width-to-thickness ratio (B/t), depth-to-width ratio (β) and recycled coarse aggregate replacement ratio (r) are tested. The test results show that rectangular RACFST stub column specimens have similar failure pattern as their counterparts. However, the bearing capacity and the composite elastic modulus of RACFST specimens are lower than those of CFST ones while they both decrease with higher r. Moreover, the specimens with larger B/t and β possess a smaller ductility index. Numerical simulation of rectangular RACFST stub columns under concentric compression is executed using a finite element analysis (FEA) model developed based on the ABAQUS software, and the predicted results are verified by the experimental observations. The mechanism of concentrically loaded rectangular RACFST stub columns is further revealed by the FEA model. Finally, simplified formulae for the bearing capacity of rectangular RACFST stub columns are proposed, with the comparison between simplified and experimental results showing that the simplified model is a good predictor.

Experimental study on the residual seismic resistance of ultra high performance cementitious composite filled steel tube (UHPCC-FST) after contact explosion

Abstract This paper aims to ex perimentally study the residual seismic resistance (RSR) of Ultra high performance cementitious composite filled steel tube (UHPCC-FST) specimen after contact explosion. Firstly, six 1/4 scaled circular UHPCC-FST were fabricated with the column height, outer diameter and core concrete compressive strength being 2000 mm, 203 mm and 131.5 MPa, respectively. Then, four of which were tested under contact explosion, in which the TNT charge weights were 1–3 kg and the height of bursts are all 250 mm. Furthermore, the RSR of both four post-blast UHPCC-FST columns and two intact control specimens were examined through the low-frequency horizontal cyclic loading test, in which two perpendicular loading directions were considered. It indicates that: (i) UHPCC-FST column suffered the localized cratering damage beneath the explosive, and the damage level became more severe with increasing the TNT charge weight; (ii) all the specimens endured the bending failure under the cyclic loadings, which occurred near the column bottom and cratering position for intact and post-blast specimens, respectively; (iii) RSR of the post-blast column deteriorated more obviously for the cyclic loading direction being perpendicular to the cratering face compared to that being parallel to the cratering face. Finally, based on the quantitative degradation of the seismic resistance, stiffness and energy consumption of the present UHPCC-FST specimens, a composite damage index was proposed to evaluate the RSR of the post-blast column after contact explosion. The present work could provide helpful references in the damage assessment and retrofitting of the post-blast column under potential contact explosions in the seismic zone.

Behavior of FRP confined UHPFRC-filled steel tube columns under axial compressive loading

Ultra-high performance fiber-reinforced concrete (UHPFRC) has been widely investigated in recent years. This study focusses on the experimental results of FRP confined UHPFRC filled steel tube (UHPFRCFST) specimens under axial compression. In total 37 specimens, both square and circular, were prepared and tested to investigate the axial compressive behaviors of FRP confined UHPFRCFST specimens. The main investigated parameters were the FRP layers, the concrete type and the steel fiber addition. The experimental results indicate that axial load capacity of concrete filled steel tube (CFST) specimens can be effectively enhanced by the FRP confinement. However, the performance enhancement was less significant for square UHPFRCFST specimens as compared to circular UHPFRCFST specimens. Comparisons of these results demonstrate that FRP confined CFST specimens exhibit a higher load-bearing capacity in the post-peak stage than the non-wrapped CFST specimens. Moreover, prediction equations were proposed to predict the ultimate axial load capacity of FRP confined UHPFRCFST specimens, and the predicted results matched well with the experimental results.

Study of Tube And Tank Specimens Repaired Using a Carbon Fibre Reinforced Epoxy

Merchant and passenger ships operate in harsh environments where they constantly suffer from corrosion and crack problems. The traditional cutting and welding of the steel parts most often requires redirection of a vessel to a shipyard what results in substantial vessel out-of-service time. In such situations, a ship operator seeks an efficient and fast repair solution to minimise ship delays. Following advancements in research and application of composite materials, an opportunity to implement composite patches made of carbon fibres and epoxy resin has emerged in the shipping industry as one of the cost and time efficient repair solutions. Although, the resin hardens and bonds the fibres strongly to the damaged surface, classification societies still consider this repair as a temporary solution and accept it conditionally, meaning with the frequent obligatory inspections. This is because there hasn’t been enough practical evidence yet to recognise the composite patching as the permanent repair solution. In order to further investigate the efficiency of the composite patching, this paper presents the finite element (FE) strength investigation of 17 patches applied to tube and tank specimens under water pressure. The future work will consider a validation of the obtained FE results by means of pressure testing during the course of the qualification process.

Experimental study on residual axial bearing capacity of UHPFRC-filled steel tubes after lateral impact loading

Concrete-filled steel tube (CFST) has been widely used in civil engineering. Numerous studies have shown that concrete-filled double-skin steel tube (CFDST) columns exhibit satisfactory mechanical properties under various loading conditions. Furthermore, ultra-high performance fiber-reinforced concrete (UHPFRC) has been developed as a prominent representative of new construction materials. This study investigates the residual bearing capacities of 10 concrete-filled steel tube specimens (three CFST columns and seven CFDST columns) after impact loading. The investigated parameters include the steel ratio, the concrete type, the section form, axial load ratio, the impact energy and the presence/absence of impact load. The results demonstrate that, when the inner steel tube thicknesses are identical, increasing the steel ratio from 0.296 to 0.467 (the outer steel tube thickness increases from 5 mm to 8 mm) can effectively improve the residual performance. For the non-impacted specimens, the bearing capacity of the CFDST columns is increased by 47.1% as the concrete type is changed from NSC to UHPFRC. For the impacted specimens, due to the influence of the test setup and other reasons, the concrete type has only a slight influence on the residual performance of CFDST columns; however, it has a substantial influence on the residual performance of the CFST columns. Furthermore, with the concrete type in the CFST columns changing from NSC to UHPFRC, the residual performance of CFST columns can be significantly enhanced.

Study of the concrete in reinforced concrete-filled steel tube column under axial loading

Experimental and analytical studies are performed to determine the response of axially loaded reinforced concrete-filled steel tube stub columns (R-CFSTs) to the strength of concrete infill. The concrete strength was set as variable in the test, and six strength levels were considered. Three specimens were fabricated for each concrete strength, resulting in a total of 18 R-CFST specimens, along with another 18 concrete-filled steel tube (CFST) specimens for comparison. Based on the experimental results, the improving mechanism of reinforcing bars on the overall performance of R-CFST was investigated. The effects of the concrete strength on the load transfer performance, steel tube, reinforcing bar, failure mode, ductility, and strength of R-CFST were examined in comparison with the corresponding values associated with CFST. The strength prediction equations proposed for R-CFST were validated using experimental data from previous research. Further, analytical studies were performed to confirm the experimental results and proposed equations. A constitutive model for the concrete core of R-CFST is proposed, and a corresponding analytical method is introduced. Finally, specific analyses are performed on the steel ratios of R-CFST and CFST. The results indicate that R-CFSTs outperform CFSTs with respect to post-peak response, ductility, strength, and brittle fracture resistance. For the same steel ratio basis, R-CFSTs with thinner tubes perform well relative to CFSTs with thicker tubes. Recommendations to configure reinforcements to guarantee good performance by CFSTs when filled with high-strength concrete are provided. Furthermore, the proposed equations are recommended for more accurate prediction of the strength of R-CFSTs.

FRP confinement of SCC incorporating expansive agent and saturated lightweight sand

Abstract This study investigated the effect of shrinkage, the use of lightweight sand (LWS) as internal curing and an expansive agent (EA) as shrinkage-reducing admixture on the confinement of self-consolidating concrete. Sixty-three concrete filled fiber reinforced polymer tube specimens were tested under axial compression. Using high EA content resulted in reduction in the unconfined compressive strength of concrete while using LWS resulted in up to 30% increase in the unconfined compressive strength at late ages. The coupled effect of LWS and EA increased the confinement effectiveness by 83%. The use of temporary confinement, in the form of rigid formwork, in conjunction with EA increased the confined strength by up to 23%.

Histopathological study of surgically resected specimens of fallopian tube

Background: Fallopian Tubes are very common surgical specimen received in the pathological laboratory. It is affected by wide spectrum of both non neoplastic and neoplastic lesions. But there is very few studies described the frequency of various histopathological spectrums of lesions of fallopian tube. Aims & Objectives: To study the various histopathological lesions seen in surgically resected specimens of fallopian tube and their age distributions.Material and Method: A total of 200 surgically resected specimen of fallopian tube of all age group of patients which are received for one and half year duration, are processed with routine histopathological techniques. Histopathological features were studied on Haematoxylin and Eosin stain.Results: In our studies majority of the cases are belongs to 40 to 60 years of age out of 200 specimens. In this study, most of the patients were undergone total abdominal hysterectomy with salpingo-oophorectomy (60%). In our study out of 200 cases 63 (31.50%) specimens show unremarkable histology. Only 1(0.50%) case shows neoplastic pathology. Most common histopathological findings observed are paratubal cyst, ectopic tubal gestation and Walthard Cell Nests.Conclusion: Present study shows broad spectrum of pathological lesions in fallopian tube. Majority of the lesions are non neoplastic in nature. Thorough histopathological examination of fallopian tube specimens is necessary to document many lesions including rare primary intraepithelial malignancy which can be missed clinically and found incidentally on histopathological examination.

Cellular automata modeling of the kinetics of static recrystallization during the post-hydroforming annealing of steel tube

A modeling setup based on the cellular automata (CA) method was developed to model the kinetics of static recrystallization (SRX) in hydroformed steel tubes undergoing the annealing process. In addition, the impact of multiaxial deformations on the kinetics of SRX within the hydroformed steel tube was investigated. First, hoop and axial strains developing at the pole of the steel tube during hydroforming were obtained from the digital image correlation measurements. Then, an exact analytical solution was employed to calculate the corresponding hoop and axial stresses at the pole of the bulged tube. Using these biaxial stress–strain curves, the stored energy was calculated for the hydroformed tube specimen. Second, the actual grain topology and crystallographic orientation of grains in the deformed specimen were obtained with the electron backscatter diffraction. Third, the calculated stored energy as well as the microstructural and crystallographic data was incorporated into the CA model as initial conditions to predict the kinetics of SRX in the specimen during annealing. Finally, to assess the accuracy of the CA model, experimental and predicted results were compared in terms of grain topology data including the grain size and aspect ratio distributions, as well as the rate of recrystallization during annealing. A reasonable agreement between the experimental and CA predictions in partial and fully recrystallized specimens was achieved inferring the validity of the developed algorithm and the modeling setup to predict the SRX kinetics during the post-tube hydroforming annealing process.

High-Temperature Thermal Properties of Sprayed and Infill-Type Fire-Resistant Materials Used in Steel-Tube Columns

In order to investigate the fire performance of steel tube and concrete-filled steel tube (CFT) columns with fire-resistant materials, high-temperature thermal properties tests were performed to measure the thermal conductivity, specific heat, and mass loss of fire-resistant materials. Conventional sprayed fire-resistant material (SFRM) and a newly developed infill-type fire-resistant material (IFRM) were examined, and stub columns fire tests were also performed to verify the measured thermal properties. Test parameters for stub column fire tests were shape of the steel tube, presence of infill concrete, and thickness and type of fire-resistant materials. A heat transfer analysis was performed to predict temperature distributions in steel tube and CFT column specimens. Comparison with the test results show that the temperature distribution can be predicted with reasonable precision using the measured thermal properties of SFRM and IFRM.

Axial crushing behaviors of composite pre-folded tubes made of KFRP/CFRP hybrid laminates

In this paper, the crushing behaviors of composite pre-folded tubes made of KFRP/CFRP hybrid laminates subjected to quasi-static axial loads are investigated both experimentally and numerically. The full-diamond origami pattern and its variation forms with curved lobes are considered for the tube design. Five pre-folded tube specimens with different ply stacking sequences consisting of CFRP and KFRP woven fabrics are manufactured and tested in quasi-static axial compression tests. The finite element models for pre-folded tubes made of KFRP/CFRP hybrid laminates are developed and validated with the experimental results. A comprehensive parametric study on the energy absorption properties of CFRP/KFRP hybrid composite tubes with various geometries is performed numerically. The results show that the energy absorption performance of the composite tubes has a strong correlation with the composition of hybrid fiber and the specimen with the stacking sequence of [0k°/0c°/0c°/0k°] has the best overall energy absorption performance among the five specimens tested. Moreover, it is found that by converting the standard full-diamond pattern to the curved variation forms, the energy absorption performance of the pre-folded tubes can be improved.

Four-point-bend tests on high-burnup advanced fuel cladding tubes after exposure to simulated LOCA conditions

ABSTRACT To evaluate the fracture resistance of high-burnup advanced fuel cladding tubes during the long-term core cooling period following loss-of-coolant accidents (LOCAs), laboratory-scale four-point-bend tests were performed using the following advanced fuel cladding tubes with burnups of 73–84 GWd/t: low-tin ZIRLOTM, M5®, and Zircaloy-2 (LK3). Three four-point-bend tests were performed on the high-burnup advanced fuel cladding tube specimens subjected to the integral thermal shock tests which simulated LOCA conditions (ballooning and rupture, oxidation in high-temperature steam, and quench). During the four-point-bend tests, all the specimens that were oxidized at 1474 K to 9.9%–21.5% equivalent cladding reacted exhibited brittle fractures. The maximum bending moments were comparable to those of the conventional Zircaloy cladding tube specimens. Furthermore, the effects of oxidation and hydriding on the maximum bending moment were comparable between the high-burnup advanced fuel cladding tube specimens and the unirradiated Zircaloy-4 cladding tube specimens. Therefore, it can be concluded that the post-LOCA fracture resistance of fuel cladding tubes is not significantly reduced by extending the burnup to 84 GWd/t and using the advanced fuel cladding tubes, though it may slightly decrease with increasing initial hydrogen concentration in a relatively lower ECR range (< 15%), as observed for the unirradiated Zircaloy-4 cladding tubes.

On the method to obtain the elastic properties using a pressurized thin tube

This paper presents a simple method for obtaining the elastic modulus and Poisson’s ratio by using a thin tube subjected to a uniform pressure. The primary target of the present work is a nuclear fuel tube, whose mechanical properties are enhanced by adding a strengthening material into the base material of zirconium alloy, e.g., a coating or a composite. It is particularly useful if the mechanical properties of the strengthening material are not provided because the conventional models of micromechanics or composite materials need the properties of all constituent materials to evaluate its effective mechanical properties. A typical example is an oxide dispersion strengthened (ODS) coated tube for an accident tolerant fuel (ATF), which is currently being developed in the worldwide nuclear field after the Fukushima accident in 2011. In this work, fuel tube specimens of pure Zircaloy-4 and those coated with the ODS are used for the experiments. A pressure of 12.76–38.29 (max) MPa is exerted inside the tubes. The elastic modulus and Poisson’s ratio of the tube material are obtained using Hooke’s law of plane stress condition and the measured axial and circumferential strains. As a result, the elastic modulus and Poisson’s ratio of the pure Zircaloy-4 are very close to the values in the open database, which validates the present method. The difference of the elastic modulus and Poisson’s ratio are not meaningfully appear for the ODS coated tube compared with those of the pure Zircaloy-4 tube. Possible experimental errors and the thin tube assumption are discussed with a simple finite element analysis.

Poor Antimicrobial Activity of Opium Against Carbapenem-Resistant Pseudomonas aeruginosa Isolates

Background: Carbapenem-resistant Pseudomonas aeruginosa (P. aeruginosa) has dramatically increased. Thus, finding a new therapeutic option is necessary to fight such isolates. Objectives: This study aimed to explore the influence of opium on carbapenem-resistant and carbapenem-sensitive P. aeruginosa. Methods: During the study period from December 2018 to March 2019, a total of 20 non-duplicate P. aeruginosa isolates were collected from clinical samples in Shahid Mohammadi and Pediatrics hospitals (teaching hospitals) affiliated to Hormozgan University of Medical Sciences in Bandar Abbas, the South of Iran. The antimicrobial susceptibility pattern was tested by the disc diffusion method according to the Clinical and Laboratory Standards Institute (CLSI) guidelines. The influence of opium was tested by broth microdilution and agar disc diffusion methods against P. aeruginosa isolates. Results: We studied 20 isolates of P. aeruginosa, of which 30%, 30%, 15%, 10%, 10%, and 5% were collected from wound, urine, discharge, blood, tracheal tube, and other specimens, respectively. According to the antimicrobial susceptibility testing results, the highest and lowest rates of resistance were to ofloxacin and piperacillin, respectively. Unexpectedly, all clinical and standard isolates of P. aeruginosa were resistant to different concentrations of opium. Conclusions: Based on our experiments, no antimicrobial effect was found for opium against the tested isolates. Studies of opium need to be continued as it may show some bacteriostatic or bactericide activities in other conditions.

Effect of Heat Treatment on Mechanical Properties and Energy Absorption Capacity of 7003 Aluminum Alloy

The effects of heat treatment conditions on the mechanical properties and energy absorption capacity of 7003 (Al-6Zn-0.6Mg) aluminum alloy were studied. The extruded material was heat treated at various temperatures to prepare annealed or aged specimens. Tensile tests, hardness measurements, electron backscatter diffraction characterizations, and differential scanning calorimeter analyses were carried out to investigate the mechanical properties and microstructures of the as-extruded or heat treated specimens. Axial compression tests of circular tube samples were also performed t℃haracterize their energy absorption behavior. Specific energy absorption was calculated by measuring the absorbed energy per unit weight of the tube specimen. The peak reaction force was defined as the maximum force applied during the compression test. The as-extruded material with high strength and low elongation exhibited fracture failure during the axial compression test. After a low temperature annealing at 200 or 250 ℃, the material had low strength and low energy absorption capacity. In contrast, the high temperature (300 to 400 ℃) heat treatment resulted in an increase in strength and enhancement of energy absorption capacity. The aging treatment effectively increased the strength and the energy absorption capacity. After artificial aging, fine and uniform precipitates were formed. The artificially aged specimens showed the highest yield strength and therefore exhibited the highest energy absorption capacity among the heat treated specimens. Specific energy absorption and peak reaction force were linearly proportional to the flow stress of the material. Key words: Al-Zn-Mg alloy, heat treatment, energy absorption capacity, mechanical properties, microstructure

The Effect of Shot Peening on Steam Oxidation of 304H Stainless Steel

Shot peening is currently utilized in coal-fired power plant components to mitigate scale exfoliation issues from steamside oxidation of austenitic stainless steel superheater and reheater tubing. To focus on commercially available material, this study exposed quarter-ring specimens cut from two different commercially shot peened type 304H tubes and exposed to 1 bar steam for up to 15,000 h at 550°, 600°, 625°, and 650 °C. Specimens were removed at increments to characterize the oxide thickness and microstructure. The shot peened inner surface generally retained a thin, protective Cr-rich scale with occasional Fe-rich oxide nodules at 550–625 °C. The increased oxidation resistance from shot peening began to degrade at 650 °C after as little as 5,000 h. Cut and polished faces of these specimens formed thick, Fe-rich oxides similar to polished 304H coupons. Surprisingly, the mechanically machined outer surface of the tube specimens performed similarly to the shot peened inner diameter, suggesting it had sufficient cold work to achieve a similar benefit. Electron backscatter diffraction and Vickers-hardness measurements were used to characterize post-exposure changes in underlying microstructure and mechanical properties, respectively, imparted by shot peening.

DEBRIS-FRETTING TEST OF COATED AND UNCOATED ZR-1%NB CLADDING

Debris fretting is one of the most significant fuel rod failure causes. An approach to mitigate this is to apply special coatings on the surface of the cladding that are supposed to increase the wear resistance. This paper summarizes the experiments performed in Research Centre Rež on fuel cladding tube specimens. The tube segments made of uncoated and coated Zr-1%Nb alloy were exposed to fretting tests simulating the wire-debris vibrations impact on cladding during the reactor operation. The goal of these tests is to obtain results about the differences in wear resistance of uncoated and coated specimens. This paper shows the testing procedure in the air at room temperature and obtained impact markings on the specimens’ surfaces.

Detection and genotyping of CMV and HPV in tumors and fallopian tubes from epithelial ovarian cancer patients

Viral and bacterial infections are detected in epithelial ovarian cancer (EOC) tissues. Since the fallopian tubes are often affected by pelvic inflammatory disease (PID) and the majority of serous EOCs appear to originate from dysplastic lesions in the distal tube, it is relevant to consider the potential role that infectious agents may play in ovarian carcinogenesis. We sought to analyze the prevalence of human papillomavirus (HPV) and cytomegalovirus (CMV) in EOC tissue and fallopian tube specimens obtained at tumor resection. Ovarian cancer and fallopian tube tissue samples obtained from patients with EOC were analyzed by both qualitative and quantitative PCR to detect and quantify viral DNA. The presence of CMV and HPV DNA was detected in 70% and 74% cancerous ovarian tissues, respectively, and was significantly higher in EOC than in benign tumor cases (P ≤ 0.01). CMV or HPV infection was observed also in the fallopian tube samples. Infection with HPV16 was determined in 70% of EOC cases. Almost two thirds of EOC patients demonstrated coinfection with CMV and HPV in the pathological samples. The results revealed that the presence of CMV and HPV in EOC samples is common. CMV and HPV infections can be potential risks for EOC development.

Bond Properties of RAC-Filled Square Steel Tubes after High Temperature

This paper presents the results of an experimental study to investigate the influence of high temperatures on the bond properties between the recycled coarse aggregate (RCA) concrete and square steel tubes. A total of 27 pushout recycled aggregate concrete- (RAC-) filled square steel tube specimens are cast and heated under five different temperatures (20°C, 200°C, 400°C, 600°C, and 800°C) for testing. The main parameters considered in the test are temperature, exposure time of heating, RCA replacement ratio, interface length-to-width ratio, and concrete strength. The experimental results indicate that the bond strength for recycled coarse aggregate concrete and square steel tube increases with increasing temperatures.