Longitudinal Steel Bars Research Articles

Using woven recycled plastic fibers in reinforced concrete beams

The modern lifestyle, along with the advancement of new technologies has produced plastic waste and the recycling of these waste materials has become an important challenge for human societies. Polyethylene terephthalate (PET) is one of the most consuming waste materials. A solution to repel these materials is to use them in the civil engineering industry and buried them in concrete. PET layers and strips were used in reinforced concrete beams instead of steel reinforcements by some researchers. But, in this study, the longitudinal and transverse steel bars were replaced by woven recycled plastic fibers and tested experimentally. These woven PET bars are produced by the authors and used as a structural element. Six beams with different combinations of steel and woven PET bars are tested under two-point loading and the experimental and analytical results are presented. The results show that using these fibers concludes to increases the ductility of reinforced concrete beams. By replacing PET ropes instead of one, two and three tensile steel reinforcements, the ductility ratios of the beams are about 1.73, 1.76 and 4.12 times of the reference reinforced concrete beam. Moreover, some theoretical formulation is presented and compared with experimental data.

A yield curvature model considering axial compression ratio

This study proposed a yield curvature prediction model considering axial compression ratio with exponential function which is improved on the basis of the specification effective yield curvature prediction model. Parametric moment–curvature curves approach was used to verify that the yield curvature is greatly affected by the section size, the yield strength of longitudinal steel bar and the axial compression ratio. On the basis, the yield curvature under different levels was obtained by Xtract and parametric moment–curvature curves approach, the result shows that with the increase of axial compression ratio, the yield curvature also increases, which is roughly a linear relationship. Subsequently, combined with the specification and considering the influence of axial compression ratio, a new yield curvature prediction model is proposed based on a massive sample space obtained by parametric moment–curvature curves approach. Moreover, by comparing with the experimental database of PEER, the accuracy of new prediction model is verified, and the result shows that the new prediction model is suitable for estimating yield curvature of square section columns.

Flexural Performance of Cracked Reinforced Concrete Beams Strengthened with Prestressed CFRP Sheets under Repeated Loads

Because researchers are aiming to restore the deformation and minimize the crack width of existing concrete structures, the strengthening technology of prestressed carbon-fiber-reinforced plastic (CFRP) is currently the focus of many studies and applications. In terms of the strengthening of a prestressed CFRP sheet on the flexural performance of cracked reinforced concrete beams under repeated loads, a four-point bending test of 12 beams was conducted considering the prestress degree reflected by the amount and the prestress force of the CFRP sheet. The longitudinal strengthened CFRP sheet was bonded on the bottom surface of the test beam and fixed by U-jacket CFRP sheets at the ends after tensioning. The strains of concrete, longitudinal tensile steel bars and CFRP sheets were measured at the pure bending segment of test beams, while the cracks, midspan deflection and failure pattern were recorded. The results show that the normal strain on the mid-span section of the strengthened beams by the prestress CFRP sheets was fitted for the assumption of plane section, the cracks and mid-span deflection decreased with the prestress degree of the CFRP sheets to provide better serviceability for the strengthened beams, the load capacity could be increased by 41.0–88.8% at the yield of longitudinal tensile steel bars and increased by 41.9–74.8% at the ultimate state and the ductility at the failure state was sharply reduced by 54.9–186%. The peeling off of broken CFRP sheets played a role in controlling the failure pattern of the strengthened beams under repeated loads. Finally, methods for predicting the bending performance of reinforced concrete beams strengthened by prestressed CFRP sheets were proposed. This study enriches the knowledge about damaged reinforced concrete beams that were strengthened with prestressed CFRP sheets.

Assessment of concrete shear resistance of lightweight SCC beams containing scoria aggregates

Lightweight self-consolidating concrete (LWSCC) has become a construction material that combines the benefits of lightweight concrete (LWC) and self-consolidating concrete (SCC). However, this combination may affect the shear resistance of structural members made with such concrete. This paper evaluates the shear resistance and performance of LWSCC beams. Eight full-scale beams without stirrups were fabricated and tested to failure. Seven beams were constructed using LWSCC and one was cast using normalweight self-consolidating concrete (NWSCC). Natural lightweight coarse and fine scoria aggregates were used in preparing the concrete mix. The beams were tested over a simply supported span in a two-point loading configuration. The test parameters comprised the type of aggregates, the reinforcement ratio of longitudinal steel bars, the shear span-to-depth ratio, and the depth of the beam. The experimental results showed that employing scoria aggregates in the mix resulted in beams with a reduced self-weight, where the obtained unit weight of LWSCC was 1800 kg/m3. Compared to the beam with NWSCC, the counterpart beam with LWSCC showed 25% lower shear strength. Additionally, the LWSCC beam experienced a reduction of 20% in the flexural cracking load while the beam showed a larger number of cracks at failure. The shear strength of the beams was predicted using the relevant shear design provisions of the American Concrete Institute building code ACI 318, the Canadian standard CSA-A23.3, and Eurocode 2. The ACI 318 method provided more reliable and conservative estimates for the shear capacity of the tested beams.

Flexural Behavior of RC Beams with NSM Prestressed Helical Rib Steel Wire

The reinforcement technique of near-surface mounted?NSM?prestressed helical rib steel wire (PHRSW) with wide raw material sources, lower in price and high application value can significantly enhance the flexural behavior of reinforced-concrete (RC) structures. Based on 8 flexural RC beams reinforced with NSM PHRSW, performance of test beams under different groove widths (10 mm, 15 mm and 20 mm) and concrete strengths (C30 and C40) was analyzed, including load-deflection, ductility, flexural capacity, strain of longitudinal steel bar and HRSW, failure mode and crack propagation. The results show that the overall flexural behavior RC beams reinforced with NSM PHRSW was significantly improved. There is a good entirety bearing capacity between the longitudinal reinforcement and PHRSW of reinforced beam with suitable groove size. The comprehensive performance of reinforced beams increases first then decreases, with the increase of groove size. The higher the strength of concrete, the more significant the influence of groove size. There is an optimal match between groove width and concrete strength for RC beams reinforced with NSM PHRSW. Considering comprehensive property of reinforced beams, groove width with 15mmwas best in this research. The results can make the research of RC beams reinforced with NSM PHRSW more comprehensive and in-depth, and provide design basis for its engineering application.

Experimental study on eccentric compression behavior of slender rectangular concrete columns reinforced with steel and BFRP bars

This study aims to investigate the eccentric compression behavior of concrete columns reinforced with a hybrid of steel and basalt fiber-reinforced polymer (BFRP) bars and ties (hybrid-RC). A total of ten slender columns were constructed and tested, including six hybrid-RC columns, two longitudinal steel bars and ties reinforced concrete (steel-RC) columns, and two longitudinal BFRP bars and ties reinforced concrete (BFRP-RC) columns. The study focused on the effects of reinforcement type, loading eccentricity, and reinforcement ratio. The test results indicated that the hybrid-RC columns with relatively higher reinforcement ratios demonstrated close load-carrying capacity and stiffness to those of steel- and BFRP-RC columns. All the columns experienced a significant reduction in their load-carrying capacities, as well as the axial and lateral stiffness, when the applied loading eccentricity increased from 80 mm to 150 mm. As the reinforcement ratio increased, hybrid-RC columns exhibited an improvement in the load-carrying capacity, stiffness, and axial force contribution of longitudinal bars in compression. Furthermore, the equations to predict the cross-sectional strength of hybrid-RC columns were proposed by theoretical analysis, and the existing methods considering the slenderness effect were evaluated for hybrid-RC columns.

Flexural strengthening of reinforced concrete beams using textile-reinforced mortar improved with short PVA fibers

Textile-reinforced mortar (TRM) composites were developed to avoid the problems caused by fiber-reinforced polymer (FRP) composites. Furthermore, short and dispersible polyvinyl alcohol (PVA) fibers were applied in TRM matrix to improve the brittle behavior and limit the crack width of TRM composites. In this study, eight reinforced concrete (RC) beams, including two reference beams and six strengthened beams, were designed to investigate the flexural behaviors of RC beams strengthened with PVA fibers-improved TRM composites. The investigation variables were (i) the longitudinal steel bar ratio, (ii) the carbon textile reinforcement ratio, and (iii) the sustaining load level. The test results indicated that (1) TRM composites could effectively limit the crack width of RC beams, and multi-crack behavior was observed in the strengthening overlay. (2) The flexural capacity of strengthened beams was enhanced as the number of textile layers increased. This enhancement came with a decrease in deformation, energy absorption, and ductility to some extent depending on the failure modes. (3) For strengthened RC beams with the sustaining load of 60kN and 96kN, the yield load was decreased by 8% and 16% respectively compared with the strengthened beam without the sustaining load. The enhancement efficiency in yield load was reduced as the sustaining load level increased. However, an acceptable reduction in ductility was obtained. Finally, based on the plane section assumption, an analytical mode was proposed to calculate the flexural capacity and deflection of RC beams strengthened with TRM composites.

Numerical investigation of the hybrid reinforced concrete beam using GFRP bars

The numerical study of the hybrid reinforced concrete beam using GFRP bars has been explored in this research. Finite element software ABAQUS had been used for numerical investigation. In the present research, the use of GFRP bars as a replacement to steel reinforcing bars for longitudinal reinforcement is attempted. Further, a RC beam by using GFRP as longitudinal reinforcement and steel rebars as transverse reinforcement is compared with the conventional steel reinforced concrete beam. The beams are tested for three-point bending using numerical simulation under displacement control. By performing the numerical modelling, load, strain and displacement data has been attained. Further, by using the output data, stress-strain curves of concrete, load versus strain variations in tension bars and load versus deflection curves are plotted. The stresses, deflections, strain developed in longitudinal bars, load carrying capacity, energy absorption are then calculated using the data and are compared. From the results it is observed that, the load carrying capacity decreases by 16% and the energy absorption increases by 29% when longitudinal steel bars are replaced by GFRP bars.

Shear behavior of reinforced concrete beams subjected to accelerated non-uniform corrosion

In this paper, a modified accelerated corrosion method based on impressing current was adopted to generate non-uniform corrosion of stirrups in reinforced concrete (RC) beams. The shear performance of corroded RC beams was experimentally investigated, aiming to study the influence of stirrup corrosion induced by two different accelerated corrosion methods on the degradation of shear capacity of RC beams. Different corrosion degree of stirrups, corrosion of longitudinal steel bars, as well as shear span ratio were investigated. Results indicates that, the stirrups subjected to the modified accelerated corrosion method demonstrate a considerably higher circumferential and longitudinal non-uniformity, while the classic accelerated corrosion method induces a rather uniform corrosion. The non-uniformity of corrosion aggravates the propagation of both corrosion-induced and load-induced cracks, leading to the change of shear failure mode. The uniform corrosion induced by the classic accelerated corrosion method underestimates the degradation of shear capacity of RC beam, especially in the cases of corrosion degree no less than 15%. The corrosion of longitudinal steel bars mainly correlates to the decrease in the initial stiffness of RC beam, while little influence on the stiffness is observed with corroded stirrups.

Quasi-static experimental study on precast concrete columns reinforced with bundled rebars

Bundled reinforcement is an alternative approach to improve the installation efficiency and structural integrity of precast concrete structures. With higher strength and lighter weight compared with steel bars, basalt fiber reinforced polymer (BFRP) bar is an attractive candidate material for concrete structures. Low-cyclic reversed loading tests on four precast concrete columns reinforced with different arrangements of longitudinal bars were conducted in this paper. The test specimens included singly arranged steel bars (S12-1P, S20-1P), three-bar bundled steel bars (S12-3P), and three-bar bundled hybrid BFRP bars/steel bars (S10/B13-3P). The test results showed that using bundled reinforcement in precast concrete columns could delay the yielding of longitudinal steel bars. Specimens S12-3P and S20-1P not only maintained the inherent bearing capacity and stiffness, but also demonstrated improved deformability of 18.1% and 6.9%, respectively, compared to the conventional precast column S12-1P. S10/B13-3P showed a 5.5% increase in peak load and a 9.1% increase in displacement ductility, which is expected to result in better seismic performance compared to that of the conventional columns. The corresponding repairable limits (based on the drift ratios) for S12-1P, S20-1P, and S10/B13-3P were 2.6%, 2.9% and 4.5%, respectively. In addition, the use of bundled bars could result in a wider curvature concentrated distribution zone, thereby increasing the plastic hinge length and providing a larger deformation capacity with the same peak curvature.

Compressive behavior of corroded reinforced concrete columns strengthened with BFRP reinforced ECC in marine environment

Corrosion of reinforced concrete (RC) columns due to chloride ions in marine environments is a significant problem. Reinforcement technologies, such as the engineered cementitious composite (ECC)-fiber reinforced polymer (FRP) reinforcement technology, have proven to be effective measures to improve the compressive capacity of RC columns. However, the confinement mechanism and design formula for this reinforcement technology remain unclear. In this study, the compressive behavior of corroded reinforced concrete column strengthened with basalt fiber reinforced polymer (BFRP) reinforced ECC was investigated by numerical analysis, including the load-displacement curves, the confinement mechanism, the stresses distributions and the effect of key parameters. Additionally, a theoretical model was developed to predict the peak load of the strengthened column. The results showed that the corrosion of the longitudinal steel bar and the stirrup were respectively significantly weakened the compressive capacity and the deformation capacity of the strengthened column; The stress in the BFRP grid reached 10% of its ultimate stress under point B, and increasing the number of BFRP grid layer was found to be beneficial in delaying the load degradation in the softening stage; The theoretical model established in this study could accurately predict the peak load of the strengthened column.

Calibration analysis of calculation formulas for shear capacities of corroded RC beams

This short communication presented the calibration analysis methods and results of calculation formulas for shear capacities of corroded RC beams. A dataset was established which involved shear tests on 93 non-corroded control and 326 corroded RC beams with corroded longitudinal steel bars, stirrups and/or bent steel bars. Then, the generalized calibration method for calculation formulas of shear capacities of corroded RC beams was proposed. Based on the shear capacity calculation formulas for non-corroded RC beams specified by the Chinese code, the corrosion-induced reduction functions for the concrete contribution term, stirrups contribution term and bent steel bars contribution term were calibrated with test results collected in the dataset. After that, the recommended reduction functions were proposed and the corresponding recommended shear capacity calculation formulas were found reliably conservative. The calibration results were dependent on the specific shear capacity calculation formulas for non-corroded RC beams. Nevertheless, the dataset is available to all readers upon request to allow them to calibrate their own calculation formulas for shear capacities of corroded RC beams. The recommended shear capacity calculation formulas could help reliable safety assessments of existing RC structures.

Experimental Study on the Bearing Performance of Rock-Socketed Concrete-Filled Steel Tube Piles under Horizontal Cyclic Loading

Rock-socketed concrete-filled steel tube piles (RSCFSTs), which have been widely used in harbors, bridges, and offshore wind turbines, were exposed to horizontal cyclic loading during service and suffered fatigue damage. For the RSCFSTs, longitudinal steel bars were welded to the inner wall of the steel tube to enhance the bonding strength of the steel tube and concrete core interface. It is essential to research the bearing performance of RSCFSTs like this, under horizontal cyclic loading. In this paper, cyclic loading tests of RSCFSTs under horizontal loading were carried out. The failure patterns of RSCFSTs during the destabilization process were generalized, and the lateral displacement development law of RSCFSTs was analyzed. The interfacial bonding characteristics between the steel tube and concrete core during the test were also discussed. Results showed that the horizontal bearing capacity of RSCFSTs decreases nonlinearly with the increase in the equal amplitude of load, and the development process of the lateral displacement-cycle number curve was divided into three phases: (I) rapid growth period, (II) fatigue growth period, and (III) sharp growth period. The larger the horizontal load was, the faster the lateral displacement entered the fatigue growth period. The duration of the rapid growth period and fatigue damage period accounts for about 90% of the total life of RSCFSTs. The stiffening form of the longitudinal steel bars welded to the inner wall of the steel tube can realize the synergistic force between the upper steel tube and the concrete core of RSCFSTs, which accounts for about 7/10 of the length of RSCFSTs. The depth of the steel tube, foundation stiffness, and bonding performance between the steel tube and the concrete core were the key factors that affected the horizontal bearing performance of RSCFSTs. Finally, some constructive suggestions are proposed for the design of RSCFSTs, including increasing steel tube embedded depth, adding a sniffer bar between the steel tube and concrete interface, etc.

Semi-empirical synergetic analysis of the shear capacity of steel fibre reinforced concrete slender beams of rectangular-sections without stirrups

Although steel fibre reinforced concrete (SFRC) has been widely used in various engineering structures, there is a lack of a reliable and unified method for predicting the shear capacity of reinforced SFRC slender beams. After conducting an extensive review of previous studies on the slender beams of rectangular-section without stirrups and the SFRC with the cold-drawn hook-end steel fibre, a database was developed based on 280 reinforced SFRC slender beams that failed in shear accompanied by 37 reinforced SFRC slender beams failed in flexure and 71 reinforced conventional concrete beams failed in shear. The comparison between the experimental results and the results predicted using existing formulae revealed that a more accurate empirical model is required to evaluate the effects of multi-factors on the shear strength of the reinforced SFRC slender beams without stirrups. Based on the model of the critical shear crack, a semi-empirical synergetic equation is developed to predict the shear capacity of reinforced SFRC slender beams without stirrups. The enhanced shear resistance of SFRC in the shear-compression zone, the dowel action of longitudinal tensile steel bars, the aggregate interlock between sides of critical shear crack, and the shear resistance of steel fibres across the shear cracks as well as the size effect of sectional depth are considered. Good prediction results with small dispersion can be obtained using the proposed semi-empirical model. Conservative and simplified equations are also provided as the lower bound of the experimental shear strength of the reinforced SFRC slender beams without stirrups for easier implementation of the proposed model in real engineering design practice.

Study on flexural behavior of concrete beams reinforced with hybrid high-strength and high-toughness (HSHT) and ordinary steel bars

To study the flexural behavior of high-strength and high-toughness (HSHT) reinforced concrete beams with negative Poisson’s ratio and special spiral grooves on the surface, fifteen beams of 250 mm × 450 mm × 3200 mm were designed and manufactured to conduct bending tests. The effects of different parameters, including the reinforcement ratio, compressive strength of concrete, loading mode, the number of HSHT steel bars in hybrid reinforcement, and longitudinal steel bars type, were studied on failure modes, crack patterns, flexural stiffness, flexural strength, ductility, and energy absorption capacity. The load versus mid-span deflection curves for concrete beams reinforced with HSHT steel bars can be divided into five stages. The concrete beams reinforced with HSHT steel bars can also bear higher residual strength (approximately 0.9 Fp) and exhibit superior crack width control ability. The peak load increases by a maximum of 22.9 % with the reinforcement ratio of HSHT steel bars increasing from 0.86 % to 1.08 %. Hybrid reinforcement can improve the service performance of concrete beams, take full advantage of HSHT steel bars, and increase the energy absorption capacity of beams. Based on strain analysis of cross-section, the flexural strength model of concrete beams reinforced with hybrid reinforcement was proposed by considering the ultimate compression strain. The calculation results show that the proposed model can accurately calculate the flexural strength of concrete beams reinforced with HSHT steel bars.

Laboratory investigation on early-age shrinkage cracking behavior of partially continuous reinforced concrete pavement

As a form of durable pavement structure commonly used in the world, continuously reinforced concrete pavement (CRCP) has prominent problems caused by irregular crack distribution in the early stage. According to the characteristics of the discontinuous distribution of CRCP longitudinal steel bar stress and active crack control method, a rigid pavement structure called partially continuous reinforced concrete pavement (PCRCP) was proposed to simultaneously optimize the crack distribution pattern and reduce the longitudinal steel ratio in this paper. Since early-age shrinkage cracking behavior is a key factor affecting its durability. This paper purposes to assess the early-age shrinkage cracking behavior of PCRCP by comparing different reinforcement methods in laboratory experiments. Research results indicated that the early-age shrinkage behavior of PCRCP is basically the same as that of CRCP. The early-age shrinkage behavior of PCRCP is significantly improved than the advanced reinforced concrete pavement (ARCP). Restricted by the boundary and longitudinal steel bars system, the concrete beam produces a top-down nonlinear temperature and humidity gradient, resulting in various degrees of shrinkage deformation at different depths inside. The active crack control method can control the early-age concrete slab to form uniform crack pattern with straight lines or fewer bending cracks, which improves early-age cracking behavior significantly. This paper is to further deepen and develop the theory of CRCP early-age cracking behavior and provide basic theory support for the subsequent experimental section studies of PCRCP.

Torsional Strength of Reinforced Concrete Beams with Brine and Olive Oil Mill Wastewater

The authors conducted a comprehensive research study on adding olive oil mill and brine wastewater to the concrete mix to investigate torsion, bending stress, shear, and compressive strength. The total number of specimens were 33 beams 100 mm (depth) × 100 mm (width) × 500 mm (length). Three beams were used as control samples, and thirty beams were divided into two groups: fifteen samples were from an olive oil mill, and the other fifteen were brine wastewater with different percentages of additive material (olive oil mill and brine wastewater), with 2.5, 5.0, 7.5, 10.0, and 15.0 % of each. The beams were reinforced with 4 ϕ 8 mm as longitudinal steel bars and ϕ 4 mm stirrups spaced at 20 mm. All specimens were tested at 28 days. It was found that the torsional strength of the samples containing brine wastewater when added at the best percentage, which is 10%, was 5.46 MPa. As is the case when adding olive oil mill wastewater with the best percentage, which is 7.5%, it was 5.16 MPa. These data are greater than the torsional strength in the reference samples, which were 4.38 MPa, meaning that the torsional strength when adding brine wastewater and olive oil mill wastewater increases by 24% and 17%, respectively. Doi: 10.28991/CEJ-2023-09-03-012 Full Text: PDF

Short and Long RC Columns with Internal WWM Reinforcement under Concentric and Eccentric Compression

Recently, various types of steel meshes were used as additional internal reinforcement for improving the confinement, ductility, and strength of the reinforced concrete (RC) columns. In this experimental study, a welded wire mesh (WWM) layer was used as an internal reinforcement in addition to the traditional steel reinforcement (longitudinal bars and transverse ties) for short and long RC columns under concentric and eccentric compression. Thirty-six square RC columns with two slenderness ratios λ (height to width ratio) of 9 and 18 were tested under compression with eccentricity ratios e/t (eccentricity to section thickness ratio) of 0, 0.13, and 0.26. The reference columns were traditionally reinforced with longitudinal steel bars and transverse ties with a reference volumetric ratio ρr of 0.44%. The other columns comprised a WWM layer wrapped outside the ties whose volumetric ratio ranged from 0.22% to 0.44%. The results demonstrated that the columns reinforced with a WWM layer in addition to traditional reinforcement showed an improvement in ductility and strength compared to those reinforced with longitudinal bars and transverse ties only. A WWM layer increased the ultimate load of the columns comprising ρr ties by approximately 16% and 9% for short and long columns, respectively. These improvements were proportional to the ties volumetric ratio.

Numerical Analysis of Cracking Processes in RC Beams without Transverse Reinforcement

The procedure of FEM calculations was presented in the paper. The numerical calculations concerned a simulation of crack distribution and propagation in concrete beams reinforced longitudinally without shear reinforcement. The analysis of the obtained FEM results showed different modes of failure in the beams when shear span-to-depth ratio was a/d = 2.5 and a/d = 1.8. In the analyzed beams, the ratio of longitudinal reinforcement and the mechanical properties of the steel bars were also changing parameters. The FEM results have showed that the shear failure of reinforced concrete beams without transverse reinforcement significantly depends on the ratio and yield strength of longitudinal steel bars. Furthermore, the results of numerical calculation for the beams of a/d = 2.5 were also juxtaposed with experiments performed by the author on two longitudinally reinforced concrete beams.

Flexural Behavior of Graphite Tailings RC Beams in Chloride Environment

This paper investigates the mechanical properties of graphite tailings concrete beams under various curing environments. The results show that the concentration of graphite tailings has an important influence on the mechanical properties of concrete. Finally, the bending characteristics of the beam and the modified bearing capacity calculation formula are obtained, which provides a theoretical basis and the reference value for the construction of green building materials. Through research, the main innovations and main findings of this paper are as follows: (1) In the three kinds of concrete experimental environment, the fracture load and ultimate load of concrete beams with graphite tailings replacement rate of 20% are the largest. (2) In the three kinds of concrete test environment, when the concrete test beams under the same load, with the increase of graphite tailings replacement rate, the mid-span deflection of concrete beams showed a trend of decreasing first and then increasing. When the replacement rate of graphite tailings sand is 20%, the mid-span deflection of the test beam is the smallest. (3) Through experiments, it is found that the normal section bearing capacity of graphite tailings concrete beams after chloride salt erosion conforms to the plane section assumption. After chlorine salt erosion, the strain of the longitudinal tensile steel bar of concrete beams with different graphite tailings sand replacement rates is the same as that of ordinary concrete beams, and the slope of the strain curve is the same, showing a linear trend. The experimental results show that the replacement rate of graphite tailings sand has an insignificant effect on the strain of steel bars. (4) The Gauss function is used to fit the experimental value of normal section bearing capacity of concrete beam, and the calculation formula of normal section ultimate bearing capacity of graphite tailings sand concrete beam under chloride environment is established. The research results of this paper have significant reference value for the study of mechanical properties of graphite tailings sand concrete components.