Application Of Axial Load Research Articles

An Experimental Investigation of Light Weight Concrete Using Pumice Aggregate for Short Wall Panel Under the Application of Axial Load

The project study with the special concrete such as light weight concrete by using pumice aggregate (Natural aggregate). One of the disadvantages of conventional concrete is having high self weight. This heavy self-weight will make it to some extent an uneconomical structural material. Light weight concrete having low density reduces dead load and increase the thermal insulation. The reduction in density is produced by using it as a replacement of coarse aggregate partially in concrete. In this Study an attempt has been made to find the compressive strength of light weight aggregate concrete using mix M25 with poly carboxyl ether admixture under the application of axial load on short wall panel. Light weight concrete is made by replacement of Coarse Aggregate of Pumice aggregates.

Axial compression performance of rubberized concrete-filled steel tubular stub columns after fire exposure: Experimental investigation and calculation models

Rubberized concrete (RuC) has emerged as a promising eco-friendly solution for structural elements, offering improved energy dissipation, damping characteristics, and ductility. Incorporating rubber particles into concrete-filled steel tubular (CFST) columns presents an environmentally conscious alternative for various structural applications. However, understanding its performance post-fire is crucial for safe design application, an area currently lacking comprehensive research. This study investigates the structural behavior of sixteen axially loaded circular RuCFST columns after exposure to fire. The columns, with diameters of 219 mm and 377 mm, are filled with normal concrete and RuC, containing 5 %, 15 %, and 30 % replacement of natural fine and coarse aggregate with rubber particles. Following ISO-834 fire standards, the specimens undergo elevated temperatures and subsequent application of compressive axial loads to determine their post-fire behavior. Analysis includes examination of failure modes, temperature-time relationships, axial load-deformation curves, and strain and stress development in the columns. Microstructural analysis using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) is conducted to study internal morphology before and after exposure to high temperatures. Results indicate non-uniform and nonlinear distributions of maximum temperatures across cross-sections, with historical temperature affecting residual capacity more significantly with increased rubber content and decreased column size. Load-bearing capacities decrease by up to 30 % and 22 % for small and large RuCFST columns, respectively, after exposure to fire. Residual axial stiffness also declines, with reductions of nearly 55 % and 42 % for small and large columns, respectively. In contrast, ductility improves in fire-exposed specimens, with columns having a 30 % rubber replacement ratio showing the highest enhancement. A novel method for calculating post-fire residual load capacity based on the average historical maximum temperature is introduced, demonstrating high accuracy and offering a valuable tool for assessing and reinforcing RuCFST columns after fire exposure.

Experimental study on the seismic performance of GFRP reinforced concrete columns actively confined by AFRP strips

This paper proposes a new type of concrete columns, which are reinforced with GFRP bars and actively confined by Aramid Fiber-Reinforced Polymer (AFRP) strips. FRP reinforcement is a non-corrosive material and has the advantages of having lighter weight, higher tensile strength, and long-term durability as compared to steel reinforcement. Active confinement has advantages over non-confined concrete columns and it is expected that the active confinement in the critical area increases the adhesion between the concrete and the rebars, strengthens the concrete cover portion of the rebars, and increases the shear capacity of the column. The literature does not show a comprehensive examination of the actively confined concrete columns that are reinforced by polymer and steel bars. Six reinforced concrete columns were cast, loaded, and tested under simultaneous application of axial and cyclic loads. Four columns were actively confined by AFRP strips at 10% and 30% of the AFRP ultimate strain in the critical area. Two columns were reinforced with steel bars, and the other two were reinforced with GFRP bars. Also, two columns with steel bars and GFRP bars, but without confinement, were utilized as the control specimens. Experimental results showed that the strain in the cover portion of the actively confined columns was reduced due to the effect of active confinement, and the strength of the concrete core increased. The active confinement increased the adhesion between the concrete and the bars and also reduced crack width, which ultimately resulted in increasing concrete strength, ductility, and energy absorption.

Influence of Variation in Tie Reinforcement Diameter on the Ductility of Reinforced Concrete Columns

Reinforced concrete columns are crucial structural elements in ensuring the strength and stability of buildings. Column ductility, which is the ability to absorb energy and undergo deformation before failure, is a primary concern in structural engineering, especially in extreme external loading situations such as earthquakes. This study aims to evaluate the influence of variation in Tie reinforcement diameter on the ductility of reinforced concrete columns using Xtract software. The research method involves creating column structure models with specified dimensions and specifications, followed by the gradual application of axial loads to each model. Three models were created with varying Tie reinforcement diameters, namely 10 mm, 12 mm, and 14 mm. Structural analysis was conducted to examine the structure's response to the applied axial and moment loads, including evaluation of stresses, deformations, and column capacities. The analysis results show differences in ductility levels among the models. The model with a 10 mm Tie reinforcement diameter achieves higher ductility levels at low axial loads but fails to meet the requirements at higher axial loads according to the SNI 1726:2019 standard. However, models with Tie reinforcement diameters of 12 mm and 14 mm also exhibit a similar pattern, with good ductility at low axial loads but failing to meet the requirements at higher axial loads. In conclusion, variations in Tie reinforcement diameter affect the ductility of reinforced concrete columns. To ensure full ductility under various axial load conditions, adjustments to the design or specifications of the reinforced concrete column structure are necessary. This research contributes to understanding the factors influencing the ductility of reinforced concrete columns and can serve as a basis for the development of more effective design methods in the future.

Extrusion and meniscal mobility evaluation in case of ramp lesion injury: a biomechanical feasibility study by 7T magnetic resonance imaging and digital volume correlation.

Introduction: The existing body of literature on the biomechanical implications of ramp lesions is limited, leaving a significant gap in our understanding of how these lesions impact joint kinematics and loading in the medial compartment. This cadaveric biomechanical study aims to address this gap by employing an innovative Digital Volume Correlation (DVC) method, utilizing 7 Tesla Magnetic Resonance Imaging (MRI) images under various loading conditions. The primary objective is to conduct a comprehensive comparison of medial meniscal mobility between native knees and knees affected by grade 4 ramp lesions. By focusing on the intricate dynamics of meniscal mobility and extrusion, this work seeks to contribute valuable insights into the biomechanical consequences of medial meniscus ramp lesions. Materials and methods: An initial set of 7T MRI imaging sessions was conducted on two intact native knees, applying load values up to 1500N. Subsequently, a second series of images was captured on these identical knees, with the same loads applied, following the creation through arthroscopy of medial meniscus ramp lesions. The application of DVC enabled the precise determination of the three components of displacement and spatial variations in the medial menisci, both with and without ramp lesions. Results: The measured directional displacements between native knees and injured knees indicate that, following the application of axial compression load, menisci exhibit increased extrusion and posterior mobility as observed through DVC. Discussion: Injuries associated with Subtype 4 medial meniscus ramp lesions appear to elevate meniscal extrusion and posterior mobility during axial compression in the anterior cruciate ligament of intact knees. Following these preliminary results, we plan to expand our experimental approach to encompass individuals undergoing weight-bearing MRI. This expansion aims to identify meniscocapsular and/or meniscotibial insufficiency or rupture in patients, enabling us to proactively reduce the risk of osteoarthritic progression.

Fracture Resistance of Posterior Tooth-Supported Cantilever Fixed Dental Prostheses of Different Zirconia Generations and Framework Thicknesses: An In Vitro Study.

The rehabilitation of free-end situations is a frequent indication in prosthetic dentistry. Cantilever fixed dental prostheses (cFDPs) made of 1st and 2nd generation zirconia are one treatment option. Due to a unique gradient technology, combinations of different zirconium dioxide generations are thus feasible in one restoration. However, data about these materials are rare. The purpose of this study was therefore to investigate the fracture resistance and fracture modes of tooth-supported cFDPs fabricated from different zirconia materials (gradient technology) and different framework thicknesses. A total of 40 cFDPs were fabricated using the CAD/CAM approach and belonged to five test groups. The different groups differed in the yttria content, the proportion of the tetragonal/cubic phases, or in wall thickness (0.7 mm or 1 mm). After completion, the cFDPs were subjected to thermal cycling and chewing simulation (1.2 × 106 load cycles, 108 N load). Afterwards, cFDPs were statically loaded until fracture in a universal testing machine. A non-parametric ANOVA was compiled to determine the possible effects of group membership on fracture resistance. In addition, post-hoc Tukey tests were used for bivariate comparisons. The mean fracture loads under axial load application ranged from 288 to 577 N. ANOVA detected a significant impact of the used material on the fracture resistances (p < 0.001). Therefore, the use of cFDPs fabricated by gradient technology zirconia may not be unreservedly recommended for clinical use, whereas cFPDs made from 3Y-TZP exhibit fracture resistance above possible masticatory loads in the posterior region.

Control of a mechanism for the application of variable axial loads in a multiaxial fatigue testing machine

Control of a mechanism for the application of variable axial loads in a multiaxial fatigue testing machine

Influence of loading type and rectangular opening on the behaviour of GFRP stiffened panels

Stiffened panels are basic parts of ship hulls and decks. Effect of buoyancy and cargo loading on the stiffened panels leads to application of axial loading and pressure loading in out-of-plane direction. Fiber reinforced polymer (FRP) stiffened panels with high corrosion resistance, high strength, high stiffness and light weight is the best alternative for conventional steel stiffened panels. Because conventional steel stiffened panels experience sever corrosion when used for marine structures. For maintenance purpose, rectangular openings are provided in ship decks. The presence of opening leads to reduction in strength, reduction in stiffness, and critical failure patterns for stiffened panels subjected to axial and pressure loading. In this study, behaviour of Glass fiber reinforced polymer (GFRP) stiffened panels with rectangular opening subjected to axial and pressure loading are studied experimentally by conducting tests. GFRP stiffened panels are fabricated in such a way that the plate and stiffeners are monolithic in construction. The effect of type of loading and the rectangular opening on the strength, stiffness and span/deflection ratio of GFRP stiffened panels are discussed. Failure pattern and maximum failure strain of GFRP stiffened panels subjected to axial and pressure loading are presented.

Settlement behaviour of geothermal energy pile under cyclic thermo-axial loads

Geothermal energy pile (GEP) foundation is a new type of sustainable geostructure that can be used as an alternative solution to the energy demand for heating and cooling of built structures. However, due to limited information of this system, the installed piles have generally been over-designed to lower the risk of the system failing. This paper presents the findings of the research carried out to evaluate the performance of laboratory scaled GEP model (model pile) under the effects of the cyclic thermal loads on the settlement behaviour of the model pile with and without the application of axial load. A small-scale model pile of 19 mm diameter and 300 mm length (150 mm embedded length) was used in the experimental work while kaolin was chosen as the model soil. The model soil was compacted at 90% maximum dry density (1.4625 Mg/m3) with optimum moisture content (17%) to obtain ‘firm’ consistency, in a container of 450 mm height and 270 mm diameter. Strain gauges were installed along the pile to monitor the temperature. The ultimate load, Qu of model pile was determined as 480 N. It is found that two cycles of thermal load decreased the settlement; the higher the values, the lower the settlement due to pile expansion and soil heaves. For thermo-axially loaded pile with two cycles of thermal load, the reduction was not significant as the effect of settlement due to axial load had caused much more settlement. For the thermo-axial loads of 50°C-100 N, 17% of the settlement at failure, sf occurred after the application of axial load. When two cycles of thermal load were applied from 29°C to 50°C, the settlement occurred reduced to 16%sf. From this study it can be concluded that the effect of two cycles of cyclic thermal loads from 29°C to 50°C on pile subjected to 21% of Qu in firm clay, is negligible. The pile could function satisfactorily as designed. However, the application of higher axial loads and cycles of thermal load may need to be studied as it could potentially cause hazard to the building due to the excessive pile settlement.

Parametric study on the residual compressive strength of RC columns subjected to different standard fire durations and load ratios

PurposeSince columns are critical structural elements, they shall withstand hazards without any considerable damage. In the case of a fire, although concrete has low thermal conductivity compared to other construction materials, its properties are changed at elevated temperatures. Most critically, the residual compressive strengths of reinforced concrete columns are significantly reduced after fire exposure. Validation of the worthiness of rehabilitating concrete structures after fire exposure is highly dependent on accurately determining the residual strengths of fire-damaged essential structural elements such as columns.Design/methodology/approachIn this study, eight reinforced-concrete columns (200 × 200 × 1,500 mm) that were experimentally examined in a prior related study have been numerically modelled using ABAQUS software to investigate their residual compressive strengths after exposure to different durations of standard fire (i.e. one and two hours) while subjected to different applied load ratios (i.e. 20 and 40% of the compressive resistance of the column). Outcomes of the numerical simulations were verified against the prior study's experimental results.FindingsIn a subsequent phase, the results of a parametric study that has been completed as part of the current study to investigate the effects of the applied load ratios show that the application of axial load up to 80% of the compressive resistance of the column did not considerably influence the residual compressive strength of the shorter columns (i.e. 1,500 and 2,000-mm high). However, increasing the height of the column to 2,500 or 3,000 mm considerably reduced the residual compressive strength when the load ratio applied on the columns exceeded 60 and 40%, respectively. Also, when the different columns were simulated under two-hour standard fire exposure, the dominant failure was buckling rather than concrete crushing which was the typical failure mode in most columns.Originality/valueThe outcomes of the numerical study presented in this paper reflect the residual compressive strength of RC columns subjected to various applied load ratios and standard fire durations. Also, the parametric study conducted as part of this research on the effects of higher load ratios and greater column heights on the residual compressive strength of the fire-damaged columns is practical and efficient. The developed computer models can be beneficial to assist engineers in assessing the validity of rehabilitating concrete structures after being exposed to fire.

Effects of Reinforcement Corrosion and Sustained Load on Mechanical Behavior of Reinforced Concrete Columns.

The effects of reinforcement corrosion and sustained axial load on mechanical performance of reinforced concrete (RC) columns were investigated in the present study. Three different degrees of reinforcement corrosion were achieved by controlling the durations of accelerated corrosion test (i.e., 16 days, 31 days, and 63 days). Three levels of sustained axial load (i.e., 0%, 30%, and 60% of the ultimate bearing capacity) were concentrically applied on column specimens. The impressing current and the sustained load were applied on column specimens simultaneously, mimicking the degradation of RC columns in real structures. Results indicated that transverse stirrups yielded higher corrosion degree than that of the longitudinal rebar under identical duration of accelerated corrosion test. The application of sustained axial load improved the performance of corroded RC columns in terms of the reinforcement corrosion, the ultimate axial load, as well as the stiffness. Additionally, more longitudinal cracks along the main rebar were exhibited for column specimens subjected to sustained axial load. For both loaded and unloaded column specimens, corrosion of reinforcing steels exacerbated the mechanical deterioration of RC columns, lowering the ultimate load carrying capacity and the axial deformation compared to the uncorroded columns.

Experimental modal analysis of a rotating tendon-loaded helicopter blade demonstrator

A novel concept which uses an internal tendon to apply a compressive force on the blades for resonance avoidance of rotorcraft, so-called ‘active tendon concept’, was put forward recently. This research enhances the active tendon concept further toward its basic experimental validation in the rotating operational conditions. To progress in this direction, a new fully dynamically instrumented demonstrator combined with the displacement-based axial load application system is developed and assessed experimentally in non-rotating and rotating conditions for the rotor speeds ranging from 0 rpm to 500 rpm and axial compressive loads ranging from 0 N to 500 N. The identified modal dynamics is used to validate the comprehensive reduced-order model which is subsequently used to support the interpretation of the rotating results where the applied experimental methods lacked in resolution of range.It is observed that the rotating system features anticipated modal dynamics in the form of centrifugal stiffening and compressive softening of the beam-dominated modes, whilst the tendon-dominated modes display rapid stiffening effects with the applied axial loads. As a result of these opposing trends, further interactional phenomena such as modal veering are observed experimentally and in model-predicted results. One consistently observed beam-dominated mode is used to extend the range of the experimental observations beyond those supported by the models toward the damping characterisation throughout the veering interactions and complex strain mode analysis.The results presented in this work confirm the anticipated modal behaviour and suggest that the rotating systems can be influenced through controllable preloads whilst in the state of rotation. Additional vibration and load control opportunities arise from the emergent and tunable interactional dynamics between the primary beam or blade system and the secondary augmented tendon preload application system.

Stress concentration in butt welded joints made without the use of linings for the formation of the root of the seam

A method for calculating stresses on the concavity contour of a butt welded joint made without the use of shims to form the weld root, which takes into account both the eccentricity of the axial load application and the concavity radius, is developed. The results of calculations using analytical formulas obtained by the proposed method are in good agreement with the results of numerical calculations by the finite element method.

Design of an Innovative Test Rig for Industrial Bearing Monitoring with Self-Balancing Layout

The remote prognosis and diagnosis of bearings can prevent industrial system failures, but the availability of realistic experimental data, being as close as possible to those detected in industrial applications, is essential to validate the monitoring algorithms. In this paper, an innovative bearing test rig architecture is presented, based on the novel concept of “self-contained box”. The monitoring activity is applicable to a set of four middle-sized bearings simultaneously, while undergoing the independent application of radial and axial loads in order to simulate the behavior of the real industrial machinery. The impact of actions on the platform and supports is mitigated by the so-called “self-contained box” layout, leading to self-balancing of actions within the rotor system. Moreover, the high modularity of this innovative layout allows installing various sized bearings, just changing mechanical adapters. This leads to a reduction of cost as well as of system down-time required to change bearings. The test rig is equipped with suitable instrumentation to develop effective procedures and tools for in- and out-monitoring of the system. An initial characterization of the healthy system is presented.

Rehabilitation of severely-destructed endodontically treated premolar teeth with novel endocrown system: Biomechanical behavior assessment through 3D finite element and in vitro analyses

ObjectiveRehabilitation of endodontically treated premolars with extensive coronal destruction through endocrown approach remains a controversial topic in reconstructive dentistry. There is no clear consensus in the literature which endocrown design with which material is the most effective restoration option for severely-destructed endodontically treated premolars. The aim of this study was to assess the biomechanical behavior of endodontically treated maxillary first premolars restored with a novel endocrown system compared to the conventional one varying the applied load type through finite element and in vitro analyses. Materials and methodsFor finite element analysis, two models representing two endocrown systems used for restoration of severely-destructed endodontically treated maxillary first premolar tooth were generated: Model C for the conventional monolithic IPS e.max CAD endocrown and Model P for the novel bi-layered endocrown (PEKKTON ivory coping veneered with cemented IPS e.max CAD). Modified von Mises stress values on the remaining tooth structure, cement lines and restorative materials were evaluated separately under axial and oblique loading of 450 N. For in vitro analysis, forty sound human bifurcated maxillary first premolars were collected, endodontically-treated, and divided into 2 main groups (n = 20) according to the system used for endocrown fabrication; Group C: the conventional monolithic endocrowns and Group P: the novel bi-layered endocrowns. All specimens were subjected to an artificial thermomechanical aging protocol. Each main group was subdivided into two subgroups (n = 10) according to the loading type (axial and oblique) applied during the fracture resistance test. Qualitative analysis using Stereomicroscopy and Scanning Electron Microscopy was performed. Data were statistically analyzed at p-value ≤ 0.05. ResultsRegarding stress distribution pattern of remaining tooth structure (enamel and dentin), both endocrown systems and cement lines under both axial and oblique load application, Model P resulted in lower stresses than Model C. The oblique stress values of all analyzed structures were higher than corresponding values resulted axially. Considering failure load, a significantly higher load was recorded for Group P when axial or oblique loading was applied (p = 0.00). A significantly higher failure load was recorded with axial loading for both main groups. With regard to failure mode, a statistically significant difference was observed between main groups (p = 0.033), with more favorable failures detected for Group P axially. ConclusionsCompared to the conventional endocrown system, the studied novel system improved the biomechanical behavior within tooth/restoration complex of the restored severely-destructed endodontically treated maxillary first premolar teeth, whatever the applied load type. Clinical significanceThe novel endocrown system using a PEKK coping veneered with cemented IPS e.max CAD can be considered a favorable promising option for restoration of severely-destructed endodontically treated premolar teeth, with more protection for residual tooth structure. It can be considered as a conservative alternative option to the conventional treatment modalities not only for normal clinical conditions, but also for parafunctional cases.

Total ankle replacement along with subtalar joint arthrodesis: In-vitro and in-silico biomechanical investigations.

Total ankle replacement (TAR) and subtalar joint (STJ) fusion, are popular treatments for ankle osteoarthritis (OA). Short endurance limits the former, and movement disability comes with the latter. It is hypothesized here that fusion of the STJ can improve the longevity of the TAR prosthesis. In this study, a fresh human cadaver's ankle joint underwent TAR surgery, and strain patterns in the vicinity of prosthesis were recorded after the application of axial compressive load on tibia, resembling stance phase of the gait. Then, STJ of the same sample fused (FTAR), and a similar test procedure was pursued. The obtained strains in the FTAR were smaller than those of the TAR (p < .01). Finite element models of the tested samples were also made, and validated by experimental strains. The validated FE models were then employed to find stress distribution on the tibial plateau and prosthesis compartments. FTAR demonstrated more regular stress profiles in bone-prosthesis interface. Also, maximum von Mises stress in the talar component of the FTAR is approximately half of that in the TAR (8 and 15 MPa, respectively). Based on the results of this study, having a more symmetric load distribution on the prosthesis after STJ fusion, longevity of the TAR may likely increase.

Stability analysis of unbonded fiber reinforced isolators of square shape

Fiber-reinforced elastomeric isolators (FREIs) are generally installed in unbonded configurations. Because of the simultaneous application of axial loads and large lateral deformations, instability of these bearings is a major concern. This paper shows the results of a large series of 3D finite element analyses (FEAs) on square-shaped FREIs. The analyses aimed at obtaining easy to use design charts where the stability limits of these devices can be rapidly determined. The output of the analyses is compared to analytical results available in literature and the limitations of well-known closed form solutions are discussed.

Simulating the model for consolidation of short bored pile in pure friction soil media

In this paper, the analysis of a numerical study for consolidation analysis of short bored pile subjected to axial loads is presented. An analysis of short-bored pile is performed using finite element analysis software Abaqus CAE with the base of procured experimental data in sand media and a comparative analysis on Ansys FEA. Three models in combination of pile and footing system were developed by the application of incremental axial load for which the displacement upon each load was analyzed taking in consideration the stresses and strains. A parametric study was conducted to study the effect of load on and it’s observed displacement on the pile with or without footing. A close correlation is found between the results obtained by the FE models and the Experimental Model solution. The results indicates that the load bearing capacity of pile–footing system increases drastically when both acts together instead of acting individually.

Analysis of the uninjured tibiofibular syndesmosis using conventional CT-imaging and axial force in different foot positions

BackgroundSyndesmosis measurments and indices have been controversial and showed interindividual variability. The purpose of this study was to analyze, by conventional axial computed tomography images and a simulated load device, the uninjured tibiofibular syndesmosis under axial force and forced foot positions. MethodsA total of 15 healthy patients (30 ankles) were studied using adjustable simulated load device (ASLD). This device allowed to perform bilateral ankle CT scans in two forced foot and ankle positions (30° of plantar flexion, 15° of inversion, 20° of internal rotation and 15° of dorsal flexion, 15° of eversion, 30° of external rotation). Axial load was applied simultaneously in a controlled manner (70% body weight). Measurements on the axial image of computed tomography were: syndesmotic area (SA), fibular rotation (FR), position of the fibula in the sagittal plane (FPS), depth of the incisura (ID) and direct anterior difference (ADD), direct middle difference (MDD) and direct posterior difference (PDD). ResultsIn patients without injury to the tibiofibular syndesmosis, the application of axial load and forced foot and ankle positions showed statistically significant differences on the distal tibiofibular measurements between the stressed and the relaxed position, it also showed interindividual variability : SA (median = 4.12 [IQR = 2.42, 6.63]) (p < 0.001), ADD (0.67 [0.14, 0.67]) (p < 0.001), MDD(0.45, [0.05, 0.9]) (p < 0.001), PDD (0.73 [−0.05, 0.73]) (p < 0.002). However, it did not detect statistically significant differences when the tibiofibular differences between the stressed and the relaxed position in one ankle were compared with the contralateral side: SA (−0.14, SD = 4.33 [95% CI = −2.53, 2.26]), ADD (−0.42, 1.08 [−1.02, 0.18]), MDD (0.29, 0.54 [−0.01, 0.59]), PDD (−0.1, 1.42 [−0.89, 0.68]). Interobserver reliability showed an Intraclass correlation coefficient of 0.990 [95% CI = 0.972, 0.997]. ConclusionsWide interindividual variability was observed in all syndesmotic measurements, but no statistically significant differences were found when comparing one ankle to the contralateral side. Measuring syndesmosis alignment parameters, may only be of value, if those are compared to the contralateral ankle.

Experimental Studies of Fiber-Reinforced Concrete under Axial Tension

The design of a stand for testing concrete and fiber-reinforced concrete specimens-"eight" in tension, which provides axial load application and minimizes the effect of stress concentration at the ends of the specimen. The design of the stand is such that the distance between the axis of load application and the central hinge is 108 cm, and between this hinge and the axis of the test specimen is 21 cm, as a result of which the load transferred to the specimen is 5.143 times greater than the applied one. At the first stage of testing, it was found that the optimal characteristics of the fiber-concrete mixture is a matrix with a large aggregate ≤ 10 mm with 1.0% fiber reinforcement. At the second stage, the ultimate strength of fiber-reinforced concrete for axial tension was determined - 1.28 MPa when reinforced with wave fiber and 1.37 MPa when reinforced with anchor fiber, which amounted to 4.1% and 4.4% of compressive strength, respectively. It was also found that concrete reinforced with anchor fiber has higher deformation properties than concrete reinforced with wave fiber.