This paper proposes a prefabricated basalt fiber reinforced polymer (BFRP) bars reinforcement of a concrete arch structure with superior performance in the field of protection engineering. To study the anti-blast performance of the shallow-buried BFRP bars concrete arch (BBCA), a multi-parameter comparative analysis was conducted employing the LS-DYNA numerical method, which was verified by the results of the field explosion experiments. By analyzing the pressure, displacement, acceleration of the arch, and the strain of the BFRP bars, the dynamic response of the arch was obtained. This study showed that BFRP bars could significantly optimize the dynamic responses of blast-loaded concrete arches. The damage of exploded BBCA was divided into five levels: no damage, slight damage, obvious damage, severe damage, and collapse. BFRP bars could effectively mitigate the degree of damage of shallow-buried underground protective arch structures under the explosive loads. According to the research results, it was feasible for BFRP bars to be used in the construction of shallow buried concrete protective arch structures, especially in the coastal environments. As important structural members, reinforced concrete arches are widely used in underground protective structures ,2,3. WitFRP (fiber reinforced polymer) materials have good corrosion resistance, lightweight, high strength, and excellent magnetic transparency. Hence, they have great potential for improving the overall performance of concrete structures ,5,6,7,8.The elastic modulus of BFRP bars is low and there is no yield phase before the bar breaks. There has been extensive research to systematically study the tensile strength, the creep resistance, the impact resistance, and other mechanical properties of BFRP bars. Studies have included replacement of steel bars with BFRP bars, to discover their effect on the overall performance of concrete members ,14. In tBFRP bars are not only used in beams, slabs, columns, and other common components ,20,21 buExplosion experiments are usually very complicated and costly. Therefore, it is difficult to conduct large-scale experiments repeatedly. However, numerical simulation can better reveal the dynamic responses of structures under the action of explosive loads by accurately controlling each explosion variable . In prevIn this paper, BFRP bars were selected as the reinforcement material to strengthen the concrete arch structure, and various simulation conditions were designed to investigate the influences of multiple factors. By combining the experimental and the numerical simulation results, a more comprehensive analysis was conducted to study the dynamic responses of shallow-buried concrete arches under explosive loads. These works provide an economical and reasonable design basis for improving the anti-blast performance of arch structures in protective engineering.The HyperMesh software was used to establish a high-precision model. For the concrete arch structure, the C3D8R hexahedral reduced integral element was used for meshing as shown in A, B, R1, R2, and ω are explosive specific constants; the last term on the right-hand side is a low pressure (large expansion) term; V is the ratio of the volume of explosive products to the volume of unexploded explosives, and E is the detonation energy per unit volume.The model consists of five material parts: air, TNT, soil, concrete, and BFRP bars . The 008E has the unit of Pa. A, B, R1, R2, V are dimensionless parameters. It is recommended to use the unit system of the gram, centimeter, and microsecond when a model includes high explosives. The remaining parameters involved are shown in Therefore, Air was simulated by the 009# constitutive model (*Mat_Null) and the EOS_LINEAR_POLYNOMIAL state equation. The specific values of the involved parameters are shown in This material model was used to simulate air. Hence, the parameters of PC, MU, TEROD, and CEROD were zero. C1, C2, C3...C9 were the 0, 1, 2, 3...9th polynomial equation coefficients which were zero when the state equation was used to simulate air.The 005# constitutive model (*MAT_SOIL_AND_FOAM_TITLE) was adopted for the soil material. The material parameters are shown in The 159# constitutive model (*MAT_CSCM_CONCRETE_TITLE) was adopted for the concrete material, which could effectively simulate the mechanical properties of the concrete materials under dynamic loads such as blast and impact. The material parameters are shown in The 003# constitutive model (*MAT_PLASTIC_KINEMATIC_TITLE) was adopted for the BFRP material, which could effectively simulate the anisotropic mechanical properties of composite materials. The material parameters are shown in The process of the TNT explosion acting on the concrete composite arch structure was a process with fluid-solid coupling. Therefore, the fluid-solid coupling analysis was adopted between the explosive air and the concrete arch structure. To achieve fluid-solid coupling, the concrete composite arch structure was established as a Lagrangian element and placed in the Euler grid of the air. The explosive was also in the Euler grid to realize the flow in the air after the explosion. The interface between the air area and the Lagrangian area realized the continuity of contact and displacement through a coupling algorithm. A rigid bottom plate was set under the arch feet to restrain the longitudinal displacement of the arch, which can prevent the arch model from detaching from the bottom plate during the explosion. The damage of the concrete elements is set as eroded when the damage exceeds 0.99 and the maximum principal strain exceeds 1.Since the slip between the BFRP bars and the concrete was not considered in this study, the common node connection mode was adopted between the BFRP bars and the concrete. The numerical simulation software was used to calculate multiple working conditions. There were 18 working conditions, as shown in To investigate the dynamic response of the BBCA under the blast load and verify the reliability of the model, the simulation results were compared with the explosion experimental results. An arched concrete member made of 8 mm BFRP bars with an arch height of 600 mm was utilized in these experiments and it was buried in the soil. The dynamic response of the arch structure was studied under the explosion of 0.2 kg TNT explosives with a standoff distance of 0.15 m.BFRP bars are composed of basalt fiber and resin matrices. In particular, the process is derived from the traditional wet layup method, but it is automated from tube to bar in one stage. The bars are wrapped during the process with a helix to give the desired screw thread form to achieve superior bond strength with concrete. As shown in The longitudinal bars of the concrete arch were arranged as 3 upper and lower bars. The spacing of the stirrups was 100 mm, the longitudinal bars and the stirrup were both 8 mm BFRP bars, and the bar ratio was 0.447%. The inner diameter of the arch was 900 mm, the outer diameter was 1200 mm, the thickness was 150 mm, and the lateral width was 300 mm.During the experiments, the arch structure was shallowly buried in the soil. As shown in As shown in The LS-DYNA software was used to conduct the numerical simulation to calculate pressure, displacement, and acceleration at the vault of the BBCA structure. Under the blast condition of 0.15 m and usage of 0.2 kg TNT, many concrete elements were destroyed at the vault of the simulated arch. There were cracks inside of the arch and the sides of the arch were damaged. An oblique circular crack was produced at the arch foot. Based on the crack development and the spalling of the concrete, the simulated and experimental damages were close.Under the same working conditions, the experimental and simulation results were analyzed. In In the modeling method, 18 kinds of working conditions for the explosion simulation were given according to the scaled distance. The numerical simulation calculation was carried out and the calculation results were analyzed and discussed.The BBCAs were damaged to various degrees under different explosion loads. When the standoff distance was 0.4 m and the amount of TNT was small, such as 0.5 kg or 1 kg, the arch structure almost maintained elastic deformation without significant damage, while there was only slight damage on both sides of the vault, categorized as ‘no damage’ or ‘slight damage’. When the amount of TNT was increased to 3 kg, the arch structure was significantly damaged. Many concrete units at the vault were broken and there was a through crack around the vault, leaving the BFRP bars exposed. There were also large cracks inside the vault. The cracks were divergent and there were many cracks and breaks on the hance. In addition, there were obvious cracks that penetrated the concrete arch outside of the hance. Oblique cracks appeared on the arch foot and the damage was severe. When the standoff distance was 0.15 m, the macroscopic damage of the arch structure became more and more serious with an increase in the amount of TNT. When the amount of TNT was 0.2 kg, as shown in The development of concrete cracks had a certain pattern. Under the action of the explosion load, the structural cracks first started from both sides of the vault because of the diffraction phenomenon of the blast shock wave. When the shock wave reached the center of the vault for the first time, it was blocked and bypassed the center to both sides; the structure had no damage or slight damage. With an increase in the explosion effect, the concrete on both sides was completely broken; the cracks spread vertically in the center of the vault and then a ring-shaped crack penetrated the vault. Due to the pit-forming effect of the explosion, there was a depression in the center of the vault exposing the internal bars. The concrete on the inner side of the vault was stretched exceeding the ultimate strain of the concrete, and the inner concrete was peeled off. At this time, the arch structure changed from obvious damage to severe damage. With a continued increase in the magnitude of the explosion, the vault had obvious displacement, the curvature of the arch structure was changed, the plastic hinge formed at the vault, and the stress of the structure redistributed. The shear force at the hance increased and the transverse cracks gradually developed into circular cracks. Because the arch foot was restrained by hinges, diagonal cracks gradually developed, and a part of the concrete was crushed. When the explosion load exceeded the ultimate bearing capacity of the arch structure, the concrete peeled off and the arch structure collapsed.From There were many working conditions in this study. To facilitate the analysis, some working conditions were taken for the analysis, their laws were summarized, and then the whole set of working conditions was studied. When the standoff distance was 0.4 m and the amount of TNT was 0.5 kg, the shapes of pressure curves of the BBCA vaults with diameters of 8 mm, 12 mm, and 16 mm were almost the same, and the peak pressure reached 3.05 MPa. At the end of the explosion, the pressure on the vault was zero and there was no residual stress.It can be seen from n is the attenuation coefficient of the explosion wave, which is normally 2.75, and By replacing the values of various parameters in Equation (1) with the SI units, the calculation formula of the peak value (MPa) of the free field pressure in the soil can be obtained:1, the pressure on the vault of each group was recorded and the Using the scaled distance of each group to calculate P0 is the calculated value of the pressure at the vault, and P1 is the simulated value of the pressure at the vault. The value of P0/P1 is the reflection coefficient of the explosion load in the soil and the arch structure. Under the working conditions of A, D, and G, that is, when the standoff distance was 0.4 m and the amount of TNT was 0.5 kg, 1 kg, and 3 kg, respectively, the reflection coefficient was inversely proportional to the scaled distance. However, under the working conditions of J, M, and P, the reflection coefficient was proportional to the scaled distance. ⅓.In By calculating the scaled distance, the peak pressure of the vault can be effectively predicted, so the structure could be designed for achieving the targeted explosion resistance. Under the impact of explosion, the pressure often reaches its peak point in a short time. Thus, it was meaningful to study the effect of the working conditions. Combining When simulating the effect of the explosion, the arch structure was destroyed with a small standoff distance and the displacement of the concrete unit at the vault ‘blew up’. Therefore, the dynamic displacement curves with a standoff distance of 0.4 m and an amount of TNT of 0.5 kg and 1 kg as well as with a standoff distance of 0.15 m and an amount of TNT of 0.2 kg and 0.5 kg were taken for the comparative study. The results are shown in When the standoff distance was 0.4 m and the amount of TNT was 0.5 kg, the displacement curves of the three BBCAs were almost the same. The first displacement peak point appeared immediately after the explosion and then the second peak point appeared due to the rebound. However, the second peak value was less than the first peak value. After that, the displacement of the arch fluctuated sinusoidally until the displacement returned to zero, indicating that the arch structure was still in the elastic stage and could maintain its original shape. When the amount of TNT increased to 1 kg, the displacement peaks of the three BBCAs were still almost the same, but there were slight differences in the elastic recovery stage. At this time, the arch structures were only slightly damaged on both sides of the vault. When the standoff distance was 0.15 m and the amount of TNT was 0.2 kg, the BBCAs with three diameters showed different responses after the arch structure reached the peak displacement. The 8 mm diameter BBCA slowly descended after reaching the peak displacement and there was still residual displacement after the explosion. At this time, both sides of the vault were damaged. The 12 mm and 16mm diameter BBCAs descended rapidly after reaching the peak displacement and finally returned to zero. Thus, the arch structure still maintained elastic deformation. By increasing the amount of TNT to 0.5 kg, the arch was significantly damaged and a large area of the concrete was broken at the top of the vault and obvious cracks appeared at the hance. At this time, the three BBCAs showed different behaviors after reaching the peak displacement. The displacement of the 8mm BBCA continued to increase and reached the maximum of 1.92 mm and then dropped. The maximum displacement of the 12 mm BBCA reached 1.31 mm and then decreased. The maximum displacement of the 16 mm BBCA reached 1.29 mm and the residual displacement of the vault was less than those of the 8 mm and 12 mm BBCAs.From the above analysis, the contribution of the BFRP bars was not significant when the arch was in the elastic deformation. While the arch structure was severely damaged, the BFRP bars could make a significant contribution to the blast resistance of the arch. The larger the diameter of the BFRP bars was, the greater the contribution to the elastic deformation capacity of the arch structure was.Due to a large fluctuation in the time history curve of the vault acceleration, only the peak values were analyzed. As shown in The use of BFRP bars has many advantages. For example, the elastic modulus is much closer to that of concrete compared with steel bars and shows obvious failure characteristics before the failure. In this paper, the strain curves of the BFRP bars on the inner side of the vault and the hance were selected for the analysis, because the outer BFRP bars of the vault were always compressed while the inner BFRP bars were more subjected to the tensile stress. The bars mainly bear the tensile stress, so it was more meaningful to study the inner bars.With the standoff distance of 0.4 m, the strain of the BFRP bars on the vault with different diameters is shown in When the scaled distance was varied, the strain of the BFRP bars reached its first peak point at 1.65 ms. However, when the amount of TNT was 3 kg, the BFRP bars had other strain peak points after reaching the first peak point.Since integral modeling was adopted and the difference in the bonding performance between the BFRP bars and the concrete was not considered, the deformation of the concrete was identical to that of the BFRP bars. That is, the strain of the BFRP bars was equal to that of the concrete. According to As shown in In As shown in The numerical model proposed in this paper could analyze the dynamic response of the shallow-buried arch structure under the blast load, according to the comparison of the macroscopic damage and data between the tested model and numerical model. The BFRP bars could improve the dynamic bearing capacity of the reinforced concrete arch structure in protective engineering.The damage of exploded BBCA was divided into five levels: no damage, slight damage, obvious damage, severe damage, and collapse. BFRP bars could effectively mitigate the damage degree of shallow-buried underground protective arch structures under the explosive loads.A change in the diameter of the BFRP bars had a slight effect on the dynamic pressure on the vault. Theoretical analysis results indicate that the pressure on the vault is determined by the explosion load and the reflected pressure coefficient during an explosion. Through the calculation of the pressure on the vault, the damage to the structure can be predicted.The relationship between the displacement of the vault and the diameter of BFRP bars is affected by the scaled distance. When the scaled distance is small, the vault displacement changed slightly with a change in the diameter of the BFRP bars. However, the vault displacement decreased markedly with an increase in the diameter of the BFRP bars, when the scaled distance is large.Increasing the diameter of the BFRP bars could reduce the peak acceleration of the arch vault, but the effect was not so significant. Therefore, when using BFRP bars to reinforce the structure, it seems this can be used as an auxiliary measure to achieve the effect of vibration reduction.When the concrete cracks and the arch structure undergoes plastic deformation, the high-strength BFRP bars could significantly help the arch concrete to maintain explosion resistance and mechanical performance.In this paper, the dynamic responses of BBCA structures under various blast conditions were studied through numerical simulation, and the macroscopic failure, pressure, displacement, acceleration, and strain were analyzed. The key factors affecting its anti-blast performance were discovered and the feasibility of using BFRP bars in a concrete arch was verified. The main conclusions are as follows:


Fiber reinforcement of concrete is an effective technique of providing ductility to concrete, increasing its flexural residual strength while reducing its potential for cracking due to drying shrinkage. There are currently a wide variety of industrial fibers on the market. Recycled steel fibers (RSF) from tires could offer a viable substitute of industrialized fibers in a more sustainable and eco-friendly way. However, mistrust exists among users, based on fear that the recycling process will reduce the performance, coupled with the difficulty of characterization of the geometry of the RSF, as a consequence of the size variability introduced by the recycling process. This work compares the behavior of RSF from tires compared with industrialized steel or polypropylene fibers, evaluating the fresh state, compressive strength, flexural residual strength, and drying behavior. The concept of Equivalent Fiber Length (EFL) is also defined to help the statistical geometrical characterization of the RSF. A microstructural analysis was carried out to evaluate the integration of the fiber in the matrix, as well as the possible presence of contaminants. The conclusion is reached that the addition of RSF has a similar effect to that of industrialized fibers on concrete’s properties when added at the same percentage. Concrete is undoubtedly the most common building material in use today. There are several reasons that explain this issue: its component materials are relatively inexpensive and easy to produce; its manufacture is comparatively simple; as this is a product delivered in a semi-fluid state, it allows for great versatility terms of shaping; and it can be applied to a large number of buildings and civil engineering infrastructures. However, its use also encounters certain drawbacks, the main one being its brittleness, i.e., its low tensile strength compared to its compressive strength, its low deformation capacity until the appearance of the first crack, along with its rapid propagation.The issue of brittleness of the materials used in construction is as old as the activity itself. Since ancient times, building materials, e.g., clay sun baked bricks, were reinforced with fibers such as horse-hair, straw, and other vegetable fibers to try to overcome this hindrance. The brittle matrix supports, surrounds and protects the fibers, providing compressive strength, while the fibers enhance the mechanical response of the composite by bridging the cracks that appear after tensile failure and providing a sort of ductile behavior post cracking.The concept of fiber reinforcement was developed in modern times specifically for its use with cement-based materials. Asbestos cement products were introduced in the early 1900s and became widely used following the development of several mechanized manufacturing processes, such as the Hatschek, Magnani  processeThe development of fibers specifically intended for concrete followed a different path from asbestos. Two different periods can be distinguished. The first one, up to the 1960s, can be considered a pioneering phase, with many ideas but few actual applications. It is a period of invention rather than scientific research, characterized by a growing number of patents. The first one is usually ascribed to A. Berard in 1874 , in CaliThe second phase of the development of fiber-reinforced concrete can be considered as the period in which ascertaining the true influence of fibers in concrete properties from a scientific perspective was discovered. This phase started in the early 1960s with the research work of Romualdi et al. ,8 in the3 of concrete (fV = 0.26%).Steel fibers are the most used type of fibers for concrete reinforcement and crack control. They have been chosen for a wide range of concrete elements such as pavements, slabs, bridge decks, beams, tunnel linings, foundations, and walls, with volume fraction rates standing at mostly below 2%. Their advantages are that they are widely available; relatively inexpensive when compared to other fibers; they present high strength, modulus, fracture toughness, and temperature resistance; and are deformable. On the downside, they are corrosion-prone, and their manufacturing cost is high if small diameters are wanted. In non-load bearing applications, such as pavements, the fiber content is usually under 0.5% by volume . A commo3 is considered (fV = 0.11%).Polypropylene fibers were first used in concrete in the 1980s ,19. ThesMost of the steel and polypropylene fibers used for concrete reinforcement are comprised of industrial products manufactured from raw materials. Over the last two decades, the concern for the sustainability of industrial processes has led to the undertaking of numerous research efforts looking for the replacement of industrial products by recycled fibers at low cost and with less environmental impact ,21.According to the 2019 statistics of the European Tire and Rubber Manufacturers Association (ETRMA), that accounts for 70% of the world tire industry turnover; in other words, 5.1 million tons of tires were produced throughout 2018 by its members . The EU A typical tire consists mainly of rubber (47–48% by weight) and black carbon (22%), though an important part is comprised of steel wires and cords (15–17%) that provide stiffness and resistance to the tire . The remAccording to these figures, ELTs suggest themselves as the potential source of more than 300,000 tons of recycled steel fibers per year. Owing to this sizeable potential, a sizable number of research works have been performed over recent decades regarding reinforcement of concrete with steel fibers recycled from tires. First attempts were carried out by Wu et al. in the US in the 1990s . Their wThe existing literature shows that most of the fibers used were obtained through the shredding process. A scant number of the works have focused on the geometric characterization of the fibers, reaching the conclusion that the main geometric characteristics, diameter and length, depend on the type of tire and the extraction process , meaningWith regard to industrial steel fibers, studies show that the addition of recycled steel fibers reduces the workability of concrete mixtures, being mainly affected by the type and content of fiber ,35. The Regarding compressive strength, the studies show that, as with industrial steel fibers, a small addition of recycled fibers does not have a significant bearing on compressive strength ,39, yet,Finally, the state-of-the-art includes a good number of works that investigate the influence of the addition of recycled fibers on the residual strength of concrete under flexural and shear loads, once the first cracking has occurred ,42,43,44However, although the review of the state-of-the-art shows that it is possible to obtain a sustainable and eco-friendly fiber-reinforced concrete through the use of recycled fibers from tires, its use is not widely implemented at present in the construction sector, despite the large potential source derived from the large number of ELTs processed each year. Most of the studies point out the distrust of the users when considering a recycled product, due to the fear of a decrease in properties compared to an industrial product , as one To overcome these drawbacks, the purpose of this work is to increase the knowledge on the behavior of recycled fibers from tires compared to the behavior of two widely accepted and trusted types of industrial fibers, steel and polypropylene. The first type is the most common material used for concrete reinforcement from the structural outlook, while polypropylene fibers are a common solution to protect concrete from the appearance of cracks due to shrinkage. This final aspect has hardly been considered in previous works dealing with recycled fibers. Likewise, a procedure for characterizing the two main geometric properties of the fibers, diameter and effective length, is proposed, in order to be able to proceed to their classification.Recycled steel fibers (RSF) from tires were used in this paper for internal reinforcement of concrete. RSF were obtained by shredding and separation . Their gfV = 0.11%) of RSF and PPF were used, named RSF-CC and PPF-CC. To assess the ability to provide residual flexural strength after the appearance of the first crack, two other mixes containing 20 kg/m3 of fiber (fV = 0.26%) were used, named RSF-RS and SF-RS.To appraise the fibers’ behavior in concrete, four different concrete mixes were devised . In ordeComposition and characteristics of the mixes followed the recommendations established in the European standard EN 14845-1 . OrdinarΛ is a coefficient which is the product of several other coefficients ; τ is the bond at the matrix interface; fV is volume of fiber per unit volume of composite; and L/d is the fiber aspect ratio, that is, the length of the fiber over its diameter.Geometrical properties of the fibers affect their reinforcement capacity. According to Naaman , a simplL/d parameter on the mechanical response of the composite, one of the main issues with RSF is their geometrical characterization. Due to its origin from different wires and its extraction process, the fibers come in a variety of diameters and lengths, twisted or with hooked ends. As a result of these diverse presentations, the most suitable characterization of the geometric properties of RSF seems to be a statistical description of the type of a frequency distribution or the plotting of a histogram of the diameter and length of the fibers.Because of the influence of the Previous works ,32,42 haRegarding the fibers’ length, characterization may be even more complicated than the diameter, due to the difficulty of measuring a linear dimension on a fiber that, being bent or twisted, occupies a 3D space. The above-mentioned works, as well as some design guides , solved To overcome this drawback, the authors of this work propose a definition of the Equivalent Fiber Length (EFL) of an RSF as the length of the longest edge of the rectangular cuboid that contains the fiber . AlthougCharacterization of the fresh state was performed by determining the consistency of each of the mixtures by the slump test according to the European standard EN 12350-2 , densityFor each of the four concrete mixes, compressive strength was determined according to European standard EN 12390-3  on threeFor the characterization of the cracking resistance performance of the PPF-CC and RSF-CC mixes, the standard test method ASTM C1581  for deteFor the characterization of the residual strength under flexural loads of the SF-RS and RSF-RS mixes, the standard test method EN 14651  Figure  for measThe number of specimens per mix for the characterization of the compressive strength, cracking resistance, and flexural tensile strength was taken from the recommendations in the standards or in the guides for the design of fiber reinforced concrete ,59,60.Finally, the integration of the RSF in the concrete matrix was assessed via microscopic observation. Back-Scattered Electron Microscopy (BSEM) with Energy Dispersive X-ray Analysis (EDAX) were made in small concrete pieces taken from both RSF-CC and RSF-RS mixes. The samples, once embedded into an epoxy resin, cut, polished, and coated with carbon were inserted in a scanning electron microscope Hitachi S-4800. This equipment has an energy dispersive analyzer BRUKER 5030.Attending to the aforementioned procedures for geometrical characterization, a random sample of 1000 fibers was measured. The sizes of the bins were established at 0.05 mm for diameters and 5 mm for Equivalent Fiber Lengths. During the mixing of the components, no fiber balls were formed with any type of fiber, including RSF, which could have compromised workability.fV = 0.11%, PPF-CC  cracked without warning at the age of 26 and 28 days, causing in practice the full decompression of the internal steel rings. On the other hand, for the rings made with the RSF-CC mix, only one of the rings gradually decompressed once the cementitious matrix cracked around day 25, without any sudden transition in the strain transfer. This post-cracking behavior indicates that the RSF provides a cracking resistance that confers ductility to the concrete. The variability in strain observed before the aforementioned ages, in which the first crack in the concrete matrix was noted, is attributed to the volume changes produced by thermal expansion caused by changes in temperature (purple line).tcr) and the average value of the stress development. The average stress rate (S) is the average of the stress rate for each ring specimen (q), calculated as:G is a constant (72.2 GPa) based on the ring dimensions used in the test method, |αavg| is the absolute value of the average strain rate factor for each ring specimen, (m/m)/day1/2, and rt is the elapsed time at cracking in days. The standard indicates that the concrete has a moderate-low potential for cracking if tcr is greater than 14 days or S is less than 0.17, and a low potential for cracking if tcr is greater than 28 days or S is less than 0.10.The ASTM C1581  test metBased on the classification according to ASTM C1581 and the results obtained for both mixes, PPF-CC and RSF-CC, shown in fV = 0.26%, SF-RS , and CMOD = 2.5 mm . The sudden drops in the load showed in the graphs in %, SF-RS a and RSF%, SF-RS b, as wel%, SF-RS c. Table fV = 0.26% (20 kg/m3) provide ductility to concrete after the appearance of the first crack, resulting in a deflection-softening behavior .From the results displayed in the graphs, it can be concluded that both types of fibers added at All tested prisms were accepted as valid results, since the crack appears in the center spam of the beam starting in the sawed section .Dispersion of the results is, as is to be expected, higher than in the compression tests. Although the standard EN 14651  does notfV = 0.26%, RSF and SF, modifies the post-cracking behavior of concrete in a similar way, providing ductile behavior and residual strength after the first crack appears.Thus, according to the results obtained for both mixes SF-RS and RSF-RS shown in BSEM with EDAX microanalysis was used for microstructural evaluation of the interfaces of the concrete matrix and the RSF. The fiber-matrix interface did not unearth any type of gap that could compromise the adherence and transmission of stress between both phases. This can be seen in detail in the images of Regarding the RSF, It must be taken into account that the process of obtaining RSF from tires by shredding is a crumbling process that could introduce some level of damage to the fibers and cannot guarantee the same level of uniformity as an industrially manufactured steel fiber. Indeed, during the supply of the RSF used in this paper, during visual inspection of the received material, some rubber residue adhered to the fibers was occasionally found and a copper-like hue was observed , which sThis apparent contamination could be a potential modifier of the chemical composition of the cement paste in the interface with the RSF. For example, the presence of certain inorganic chemical elements associated with rubber manufacture (such as Sulphur S and Zinc Zn) in unusual percentages in conventional cement pastes could compromise the fiber-matrix adherence ,63. ThusMore than 80 specific EDAX microanalyses were performed on the cementitious matrix and on a ring that surrounds the interface with the fiber. The microanalyses were carried out from the fiber up to approximately 30 µm away. No appreciable differences were detected between the chemical composition of the cement paste and the RSF-matrix interface, with highly similar Al/C and S/C ratios. Only in a few of the areas analyzed, a slight increase in the C/Si ratio in the ring near the RSF-matrix interface was detected. In turn, unconventional presence of elements such as Zn and S in the matrix or in the interface was not detected.Thus, according to the BSEM images and EDAX microanalysis taken on the fiber-reinforced concrete samples studied, good integration and adhesion of the RSF in the cementitious matrix is deduced. This good integration of the RSF, despite its intricate shape, and bonding with the cementitious matrix, is then corroborated by the results obtained in the residual tensile strength tests carried out according to the standard test method EN 14651 .The use of recycled steel fibers (RSF) from tires is viable, thus obtaining a sustainable and eco-friendly concrete.The variability in the shape and length of the RSF obtained by a shredding process makes a statistical analysis necessary to characterize their geometric properties. To aid in this characterization, the concept of Equivalent Fiber Length (EFL) has been defined as the length of the longest edge of the rectangular cuboid that contains the fiber.The addition of RSF has a similar effect on the workability of concrete as the addition of industrial fibers such as steel (SF) and polypropylene fibers (PPF), when added in similar proportions.RSF have the same effect on compressive strength as industrial fibers SF and PPF, when added in the same proportions. As with industrial fibers, there appears to be a fiber content threshold beyond which a decrease in strength occurs.fV = 0.26%), providing a residual strength once the first crack appears in the concrete.The addition of RSF modified the brittle behavior of plain concrete under flexural loads, providing ductility to the material. RSF offer similar performance as industrial SF for low contents by volume (RSF can control drying shrinkage cracking during the first days as concrete in a similar way as industrial PPF for the same content of fiber in terms of volume, thereby reducing the potential for cracking.Microstructural analysis has shown a good integration and adhesion of the RSF with the cementitious matrix, without the presence of potential contaminants.Based on the results showed in this paper, the following remarks can be drawn:


This paper analyzes concrete fine aggregate (sand) modification by scrap tire rubber particles-fine crumb rubber (FCR) and coarse crumb rubber (CCR) of fraction 0/1 mm. Such rubberized concrete to get better bonding properties were modified by car-boxylated styrene butadiene rubber (SBR) latex and to gain the strength were modified by glass waste. The following tests—slump test, fresh concrete density, fresh concrete air content, compressive strength, flexural strength, fracture energy, freezing-thawing, porosity parameter, and scanning electron microscope—were conducted for rubberized concretes. From experiments, we can see that fresh concrete properties decreased when crumb rubber content has increased. Mostly it is related to crumb rubber (CR) lower specific gravity nature and higher fineness compared with changed fine aggregate-sand. In this research, we obtained a slight loss of compressive strength when CR was used in concrete However, these rubberized concretes with a small amount of rubber provided sufficient compressive strength results (greater than 50 MPa). Due to the pozzolanic reaction, we see that compressive strength results after 56 days in glass powder modified samples increased by 11–13% than 28 days com-pressive strengths, while at the same period control samples increased its compressive strength about 2.5%. Experiments have shown that the flexural strength of rubberized concrete with small amounts of CR increased by 3.4–15.8% compared to control mix, due the fact that rubber is an elastic material and it will absorb high energy and perform positive bending toughness. The test results indicated that CR can intercept the tensile stress in concrete and make the deformation more plastic. Fracturing of such conglomerate concrete is not brittle, there is no abrupt post-peak load drop and gradually continues after the maximum load is exceeded. Such concrete requires much higher fracture energy. It was obtained that FCR particles (lower than A300) will entrap more micropores content than coarse rubbers because due to their high specific area. Freezing-thawing results have confirmed that Kf values can be conveniently used to predict freeze-thaw resistance and durability of concrete. The test has shown that modification of concrete with 10 kg fine rubber waste will lead to similar mechanical and durability properties of concrete as was obtained in control concrete with 2 kg of prefabricated air bubbles. The road network is of vital importance for every country as part of their economic growth. In European Union countries, almost 90% of roads are of bituminous pavement. The maintenance costs of bituminous pavement is high compared to the construction costs . The damThere is a massive amount of different waste products getting disposed of every year all over the world and some of the wastes can be used in whitetopping concrete . Among wRubber is a naturally hydrophobic material. Generally, a high amount of silicon contributes to rubber’s hydrophobic nature, and in some cases zinc stearate also creates this hydrophobic nature (zinc stearate is one of the tire manufacturing product) . Rubber’In the world, about 130 million tonnes of glasses are generated annually . In 2018In European countries, pavement structures are mainly affected by the freezing-thawing effect, which reducing concretes age. Air-entraining agents can control a freezing-thawing effect. The researchers found that waste crumb rubber is acting similar to a traditional air-entraining agent because rubber entrapping air in concrete due to its non-polar surface nature—entrapped air creating pores called airvoids. Those pores help to hold and release the water pressure and protects from a freezing-thawing effect. Pore size depends on aggregates, and pore spacing should be around 0.25 mm for better freeze-thaw.By continuing previous research  the main2/kg was used. The chemical composition of cement is given in 3, was used as fine aggregate. A portion of sand was replaced by crumb rubber obtained from used tires. Crushed granite of fraction 4/16mm, particle density 2720 kg/m3 was used as coarse aggregate. All concrete mixes were made with the same amount of coarse aggregate, 999 kg/m3 of concrete. Polycarboxylate polymer-based plasticizing admixture was used. Modified polycarboxylates properties: appearance–light brown liquid, density—1.07 ± 0.005 kg/lit, pH value—4.5 ± 1, chlorine ion content was <0.2% by weight, sodium oxide content was <0.4% by weight. In this research, 0.8% (wt. of cement) of water-reducing admixture were used in concrete. Organic compounds-based shrinkage reducing admixture was used in this research. Shrinkage reducing admixture properties: appearance–transparent liquid, density-0.94 ± 0.02 kg/lit, pH value-6.0 ± 1, chlorine ion content was <0.1% by weight, sodium oxide content was <0.1% by weight. In this research, 2.0% (wt. of cement) of shrinkage reducing admixture were used in concrete. Coarse crumb rubber 0/1fr. (CCR) and fine crumb rubber 0/1fr. (FCR) was obtained from the different local waste tire recycling companies. Rubber particle size distribution (fine crumb rubber and coarse crumb rubber) is shown in 3, bulk density 475–485 kg/m3. CR was added 5 kg/m3, 10 kg/m3 and 20 kg/m3 in concrete and part of sand was changed by CR. In this research, mixed white and green color waste beverage bottles were crushed with an electronic crushing machine. According to ASTM C618-02, recycled glass powder is an excellent pozzolanic material. In this research, we used glass powder with size <300 μm. Properties of glass powder: density—2266 kg/m3, bulk density—1245 kg/m3. The chemical composition of glass powder is given in 2 and Na2Oeq oxides. Acrylonitrile polymer-based Sika Aer Solid was used as pre-fabricated air bubbles. The density of prefabricated air bubbles is 200 kg/m3. In this research, liquid-polymer-based carboxylated styrene butadiene latex was used for rubber surface treatment. Crumb rubber was dispersed entirely in SBR latex using the ultrasonic dispersion method. Time taken for dispersion about 1min and this process was carried out at power 250 W. Properties of SBR latex: density ~1.03 kg/dm3, pH value ~10. The fiber used in this research is chemically based on polyolefine. Polyolefine fiber comprises 85% of polypropylene, and polyolefine is from the polypropylene and polyethylene family. Properties of polyolefine fiber: density ~0.91 kg/L, melting point ~170 °C, tensile strength ~430 MPa, and tensile modulus of elasticity ~6 GPa. Polyolefine fiber dimensions: 60 mm length and 0.84 mm diameter.Concrete mixes with different fineness crumb rubber from different suppliers , glass pThe concrete mixes were prepared in the laboratory using a forced type Zyklos concrete mixer. The concrete was mixed and the concrete specimens were formed according to standard EN 206.In this study, crumb rubber granulometry was done according to EN 933-1 , the airFG is fracture energy, tW is total energy, D is specimen depth, oa is notch depth, b is the width of the specimen,rW is the area under CMOD curve, wP is equivalent self-weight force, δf is displacement under the curve,oW is the weight of the specimen, S is span length, L is the length of the specimen.Different mixes were made under laboratory conditions to determine the effect of crumb rubber addition on the durability properties of hardened concrete: reference mix with prefabricated air bubbles (Control), concrete with different fineness and amounts of crumb rubber, rubberized concrete with SBR latex and rubberized SBR latex modified concrete with glass powder wastes were prepared  for the Fresh concrete properties are described in 3. Naturally, rubber was a low specific gravity material than the fine aggregate. From experiments we can see that when crumb rubber content increased, fresh concrete density decreased due to its low specific gravity nature. There is another important reason for density lowering: air content (entrapped by rubber–nonpolar nature) rises due to the high specific area of fine crumb rubber. Adding glass powder with treated rubber were showed lower density than other samples because both glass powder and rubber have a very low particle density than sand and cement. Therefore, glass rubber concrete’s fresh density will decrease when cement (glass replacement) and sand (rubber replacement) content are reduced, these all are basic reasons. Additionally, there is another compelling reason for lowering glass concrete fresh density: glass particles are also entrapping air in concrete due to its surface nature and geometry. As a result, increasing rubber and glass content, air voids will increase, and fresh concrete density will decrease.The fresh concrete density and air content are interconnected. When air content gets increased, fresh concrete density will get decreased. Changing materials in concrete can change their property. In the fresh concrete density test, we can see that density varies for different materials. The fresh concrete density for a control mix is 2450 kg/mThe air in concrete is essential for freezing-thawing resistance. We used a special air-entraining agent (prefabricated bubbles) in a control mix, which executed about 2.5% air content. The fresh concrete pores are almost closed porosity. The rubbers’ non-polar nature will repel water and entraps air easily into the concrete. From 2 (2). The efficient compressive strength of CR concretes was achieved due to tiny size rubber particles occupied micropores between cement paste and aggregates and because of small amounts of CR was added in concrete. The literature [The compressive strength of the control mix is 56.8 N/mm2 . From thterature  proved tCrumb rubber has been treated with SBR latex to ensure homogenous rubber distribution and better bonding between rubber and cement paste. SBR latex will form a chemical bond between rubber and cement hydration products (C-S-H) for superior strength. In this research, we can see that SBR latex modified rubber concrete showed less compressive strength than rubberized concrete without SBR latex and control mix. Strength reduces for 5, 10, and 20 kg of LCR was about 21.1%, 16.9%, and 17.9% compared with control samples average compressive strength values. The reason behind insufficient compressive strength is due to the high amount of SBR latex, which brings more porosity to concrete (porous nature of crumb rubber samples is shown below SEM pictures). That porosity made concrete less dense and weakened under compressive force. The literature  showed r2, GLCR20—44.1 N/mm2. Compressive strength reduced after 28 days for batches GLCR10, GLCR20 about 20.6%, 22.3% than a control mix. Compressive strength results of samples where glass powder was added after 56 days was: GLCR10—50.1 N/mm2, GLCR20—49.8 N/mm2. Strength reduced after 56 days for batches GLCR10, GLCR20 about 13.9%, 14.4% than a control mix at the same age. We see that compressive strength results after 56 days in glass powder modified samples increased 11–13% than 28 days compressive strengths, while in control samples at the same period was obtained 2.5% compressive strength increase. Therefore, from these 56 day results, we can say that pozzolanic reactions of glass powder started working in rubberized concrete. However, we can expect that glass powder will increase concretes strength slowly and at later stages due this pozzolanic reaction. Elaqra et al. [Compressive strength of rubberized concrete with glass powder waste was tested after 28 days and 56 days because the pozzolanic reactions of glass powder will take place at later stages. Glass powder waste modified concrete compressive strength results after 28 days: GLCR10—45.1 N/mma et al.  used fina et al.  with gla2  Much lower compressive strength results which is related with flexural strength results; (2) A high amount of SBR latex liquid used in concrete, which developed more porosity; (3) There was no strong bond between rubber and cement paste . The literature  explaineConcrete potential against fracture can be determined by calculating fracture energy. In this research, fracture energy was calculated to estimate crumb rubber toughness and fibers toughness. Fracture energy can be calculated by finding an area under a flexural stress-strain curve until failure. An area under the curve tells about the ability of concrete energy absorption. For example, a larger area represents that concrete can absorb greater energy before failure. Generally, fiber-reinforced concrete will take a long time for failure than non-fiber-reinforced concrete, and fiber-reinforced concrete will have more significant displacement and area (under the CMOD curve). In this research, polyolefine fiber was used in all samples, and we used Originpro analyzing software to find an area under CMOD curve a–c. From300) which positive influence resistance to freezing-thawing of concrete. While SBR latex modified rubberized concrete compressive strength after 200 freezing-thawing cycles increased by 11.98% (50.2 MPa), 8.59% (51.1 MPa) and 8.33% (51.1 MPa) for LCR5, LCR10, and LCR20 samples accordingly than pre-freeze-thaw compressive strength values. In LCR samples was obtained a high amount of porosity which gave the strength reduction, but the same high amount of porosity gave the positive durable property to concrete. We can see the porosity nature (due to SBR) of LCR set concrete from the microscopic analysis. Those porosities gave space for water expansion due to freezing-thawing. Freezing-thawing resistance of concrete modified by glass powder waste are shown in 300) sieve is 20%, while in coarse crumb rubber is 1%. We can state that fine size crumb rubber created more micropores, which made concrete more durable during the freezing-thawing resistance.In this research, we investigated the performance of crumb rubber, SBR latex modified crumb rubber and crumb rubber with glass powder concretes after 200 freezing-thawing cycles. The freezing-thawing results of all samples were compared with control concrete. Generally, there should be a minimum amount of air in concrete to perform against the freeze-thaw effect. A traditional air-entraining agent or special air-entraining agent will use in concrete for a better freeze-thaw effect in the industries. So many years before, researchers found that rubber can act as an air-entraining agent in concrete. Due to its non-polar nature, rubber entraps air in concrete, which provides space for pressure release during water freezing-thawing. Fine crumb rubbers will entrap more air content than coarse rubbers because due to their high specific area. A rubber amount should be reasonable for sufficient air content in concrete. In this research, we added 5, 10, 20 kgs of crumb rubbers in concerts. After 200 cycles, a control mix compressive strength was obtained 57.5 MPa; it increased by 1.19% compared to zero cycles compressive strength . After 2Porosity is the prime factor for concrete performance in a mechanical and durable environment. Concrete’s total porosity, open porosity, and close porosity are calculated by using a water absorption test. After 48 h of water absorption test, a control mix absorbed 4.03% of water . UntreatWhen glass powder was added to SBR latex modified rubberized concretes, it decreased the amount of open porosity and increased close porosity content . Due to 3 of fine crumb rubber showed less frost resistant factor (Kf) compared with LCR and GLCR mixes but it exhibited good freezing-thawing performance. The reason behind that performance is that fine crumb rubber is a very finer particle than sieved normal crumb rubber, so FCR10 entrapped more micropores in concrete (A300), which made good durable performance in the freezing-thawing test.From In this paper, a scanning electron microscope was used to project: (1) prefabricated air bubbles in control concrete a; (2) crSEM analysis clearly showed that SBR latex modified crumb rubber concrete contains lots of pores; those pores decreased such concrete performance in both the compressive and flexural field. However, the pores helped positively during the freezing-thawing effect. Porosity parameter analysis also explained that SBR latex modified rubberized concrete has high porosity amount than other investigated concretes untreated crumb rubber concrete. When rubber content increased, the workability decreased due to its irregular shape and fineness and that fine crumb rubber acts as a filler in concrete. Rubberized concrete mix modified with SBR latex showed higher workability compared to control mix due to the fluid nature of SBR latex and higher porosity which gives more softer concrete mix. When glass powder was added, it increased workability due to glass particles smooth surfaces.From experiments we can see that when crumb rubber content increased, fresh concrete density decreased, and air content increased due to its low specific gravity nature. Adding glass powder in rubberized concrete were showed lower density than other samples because both glass powder and rubber have a very low particle density than sand and cement.When rubber amounts increased, compressive strength get decreased due to rises of air voids and cracks . However, these rubberized concretes with a small amount of rubber provided sufficient compressive strength results (greater than 50 MPa). We see that compressive strength results after 56 days in glass powder modified samples increased 11–13% than 28 days compressive strengths, while in control samples at the same period was obtained 2.5% compressive strength increase. Therefore, from these 56 day results, we can say that pozzolanic reactions of glass powder started working in rubberized concrete.The flexural strength of rubberized concrete with small amounts CR were increased by 3.4–15.8% compared with a control mix, due the fact that rubber is an elastic material and it will absorb high energy and perform positive bending toughness. The test results indicated that CR can intercept the tensile stress in concrete and make the deformation more plastic. The fracturing of such conglomerate concrete is not brittle, there is no abrupt post-peak load drop and gradually continues after the maximum load is exceeded. Such concrete requires much higher fracture energy.3 of fine size crumb rubber created enough micropores, which made concrete durable during the freezing-thawing resistance. Freezing-thawing results have confirmed that Kf values can be conveniently used to predict freeze-thaw resistance and durability of concrete.Due to its non-polar nature, rubber entraps air in concrete, which provides space for pressure release during water freezing-thawing. Fine crumb rubber particles (lower than A300) will entrap more air content than coarse rubbers because due to their high specific area. We can state that 10 kg/mIn SEM analysis we can see that fine crumb rubber particles are much smaller that CR and it gives smaller pore size around rubber and cement stone contact zone. These pores and rubber particles give damping effect for freezing water which gives better concrete resistance to freezing-thawing.3 of prefabricated air burbles can be successfully replaced by 10 kg/m3 of fine crumb rubber to get the similar mechanical and durability properties.From all results we can state that 2 kg/mThe following conclusions are made in this research:


Copper slag (CS) is produced during the smelting process to separate copper from copper ore. The object of the experimental research is to find the optimum percentage of CS and PPF volume fraction when CS replaces fine aggregate, and PPF volume fraction when subjected to impact loading. Copper slag was incorporated as 20%, 40%, 60%, 80% and 100% with PPF of 0.2–0.8% with 0.2% increment. The number of blows on failure of the specimen increases as the fibre volume increases. In addition, the energy absorption of composite concrete is higher than that of ordinary concrete. Concrete with up to 40% CS and 0.6% PPF volume shows a 111.72% increase in the number of blows for failure as compared to the control specimen. The impact resistance at failure was predicted by regression analysis, and very high regression coefficients of 0.93, 0.98 and 0.98 were obtained respectively at 7-, 14- and 28-days curing. In addition to regression analysis, a two-parameter Weibull distribution analysis was used to obtain reliable data on the number of blows at first cracking and eventual failure. The energy absorption at 28-day curing period is 1485.81 Nm which is 284% higher than the control mix. Based on the findings, it can be inferred that adding CS up to 60% densifies the microstructure due to its pozzolanic activity, while polypropylene fibre acts as a micro reinforcement, increasing the number of blows. Cement mortar concrete is widely acknowledged as the most extensively employed construction material on the globe. The advancement in infrastructure in the world has accelerated the use of concrete . Large qResearchers are attempting trials to recycle, reduce and reuse the industrial wastes in different ways such as construction material or by developing new value-added products ,9,10. Co3)) in control concrete was converted into a calcium-silicate-hydrate reacted component [3O4 (magnetite) and Fe2SiO4  as the primary phases in XRD analysis. Hydration is measured by the formation of a calcium hydroxide peak in the control concrete. A slight increase in the calcium hydroxide peaks for 10% replacement of CS is observed compared to ordinary concrete [The microstructure studies of CS explored that silica, alumina, lime and magnesia are available in copper slag. The oxides of silica-alumina, ferrous and magnesium make up 95% of the total mass of chemical constituents . The addomponent ,18. The concrete .3C6 hydrocarbon polymer. The polypropylene fibres are classified as monofilament and fibrillated fibre. Fibrillated fibres are made by forming slits in a plastic film having micron thickness. Fibrillated fibres are stretched to a particular length making a fibre bridging phenomenon that improves the hardened characteristics of concrete [Cracking is a critical parameter that predominantly affects the durability, structural integrity, bonding between binder and fillers and load bearing capacity. Even the micro-cracks are the pathfinder for making wider cracks . Fibre-rconcrete ,32. Hybrconcrete . Plain concrete is a heterogeneous material, and it does not sustain the sudden or time dependent loading such as impact and dynamic loading. The structure’s response to the dynamic loading becomes essential when forces like an earthquake, wind force, fluid sloshing and heavy machinery vibration act. An impulsive loading is possible in constructing the foundation for heavy machinery and circumstances like pile driving for the particular case of foundations . These fThe novelty of this research work is finding an alternate material for fine aggregate in concrete making. The new material should be waste material from industry also disposed of or dumped in open land; because waste utilization in concrete leads to a sustainable environment. Copper slag is an environmental pollutant discharged or dumped in open ground by Sterlite Industries that induces pozzolanic property when mixed with cement. Incorporating copper slag in concrete improves the mechanical property of concrete. At the same time, the depletion of natural resources like river sand leads to a search for an alternate material to fine aggregate in concrete. Hence the applicability of copper slag as a fine aggregate is verified and the impact resistance of concrete was evaluated. Copper slag available in a similar size fraction as river sand can be used as an alternate material to river sand. It is the reason to replace the copper slag with fine aggregate. To improve the inherent properties, reduce crack propagation and reduce the shrinkage effect, PPF was selected to incorporate concrete along with CS. Past literature was found in the analysis of various mechanical and durability characteristics of copper slag concrete in combination with other waste materials. However, there is no detailed investigation involved in analysing the effect of replacement of CS to river sand in fibre reinforced concrete. This research extends the analysis of copper slag concrete admixed with fibrillated polypropylene fibre subjected to impact loading. The impact resistance of copper slag concrete admixed with polypropylene fibre is the main focus of this research. The main objective of the study is to obtain an optimum replacement of copper slag and optimum volume fraction of polypropylene fibre. The research question of the study is how the CS and PPF combinedly participate in forming a dense microstructure to resist the impact loading and what the optimum replacement of CS is and how much PPF needs to be admixed? Mechanical properties, such as compressive strength and tensile strength of CS-PPF concrete is analysed and compared with control mix. Microstructure of the control concrete and CS-PPF concrete is also compared. That scarcity of natural river sand amplified the research on the feasibility of CS in concrete production. Sterlite Industries India Ltd. Thoothukudi, India, Tuticorin is facing a huge problem disposing of the copper slag into the environment without proper treatment. The plant produces around 4 million tons of copper slag per year. The chemical composition, particle size distribution and low water absorption are CS’s potential beneficial characteristics, enhancing mechanical and durability properties. The chemical composition revealed that the copper slag contains enough oxygen components to act as a natural pozzolan. Hence, the research was extended to incorporate some admixture-like fibres to upgrade the performance of concrete. Fibrillated PPF was added to the CS concrete to improve the intrinsic characteristics such as tensile strength, modulus of elasticity, impact and toughness of concrete to reduce shrinkage cracks. There is still lack of studies available on 100% replacement of CS replacement with PPF on impact resistance of copper slag concrete. 2/kg and 0.60% residue on 90 µm sieve IS1727 [3 bulk density, 1.25% water absorption, specific gravity of 2.51 and fineness modulus of 2.74 were used. The grading zone of fine aggregate is zone II in which 79% of mass is presented between 0.15 and 1.18 mm mesh sieves. Copper slag was obtained from the open disposal at Sterlite Corporation of India, Tuticorin. It has specific gravity of 3.56, of bulk density of 2088 kg/m3, 2.99 fineness modulus and 0.15% water absorption. The specific gravity of CS is 41.8% greater and CS absorbs 88% less water than river sand. Leaching of heavy metals in copper slag are within allowable limits. Regarding, heavy metal leaching, the study of copper slag revealed that copper slag leaches 0.0368 ppm withing 24 h, and by the end of 180 days it was 0.668 ppm. Both the values are under permissible limits according to TCLP (toxic characteristic leaching procedure) test [3. Aggregate was tested according to IS 2386 design code [3, 10 to 12 mm graded length, 35–40 µm thickness, and 15–18% elongation conforming to ASTM C-1116 [Chettinad ordinary Portland cement of OPC 43 grade conforming to BIS 8112, 2013  was usede IS1727 . The tese IS1727 , 35 minue IS1727 . Conplase IS1727 . It has re) test . U.S. Enre) test ,43. Coarign code . FibrillM C-1116 .2 (M30 grade). Different mix proportions were arrived on for 20, 40, 60, 80, and 100 percentage of CS replacement. Fibrillated polypropylene fibre was admixed as the percentage of 0.2, 0.4, 0.6 and 0.8 percentage of the volume of concrete. In total, 29 mix proportions were designed, including the control concrete. Mix identification C0P0 is given to control concrete where ‘C’ represents copper slag and ‘P’ represents PPF volume fraction. C denoted from 0 to 100 and P indicated from 1 to 4 for corresponding PPF volume fraction of 0.2–0.8%. The target mean strength of M30 mix is 38.25 N/mm2 as per mix design calculation. 3, 0.41 kg/m3 and 1343 kg/m3, respectively. The concrete mix proportion was prepared according to BIS 10262, 2019 . Seven pPrevious studies have described the methods of fabrication of the impact testing machine . A 34.33The steel ball weighs 1 kg and has a diameter of 65 mm. It arrests the lateral movement of the steel ball. The steel ball transfers the impact load to the specimen. The drop hammer is then placed vertically with its base on the steel ball. The hammer is hoisted and dropped repeatedly to check its verticality and free-fall.The size of the specimen specified by the ACI committee for this study was a circular disc with a diameter of 152 mm and a height of 63.5 mm [For each specimen, the numbers of blows at first crack (N1) and at ultimate failure (N2) were recorded. The following formula given in Equation (1) was used to compute the impact energy given to each sample: 2, which is 6.55% higher than the strength of the control concrete and 3.5% more than the target mean strength. In 2 which is 14% higher than the strength of the control concrete and 10.8% more than the target mean strength. Copper slag 20% contributes 2.54–21.54% increase in compressive strength compared to the control specimen in overall curing periods. The maximum compressive strength of C40P2 mix at 28 days is 46.67 N/mm2, which is 25% higher than the strength of the control concrete and 22% more than the target mean strength. The maximum compressive strength of C60P1 concrete at 28 days is 45.48 N/mm2, which is 22% higher than the strength of the control concrete and 18.9% more than the target mean strength. The maximum compressive strength of C80P1 concrete at 28 days is 46.22 N/mm2, which is 24% higher than the strength of the control concrete and 20.83% more than the target mean strength. The compressive strength of C100P4 concrete at 28 days reduces by up to 16%, the highest reduction observed in this experiment. The decrease in compressive strength is due to the excess copper slag, which dilutes the mix where fibre does not disperse properly. From the existing literature [The maximum compressive strength of C0P4 mix at 28 days is 39.60 N/mmterature , the hig2, which is 31.58% greater than the reference mix. Parveen et al. (2013) [The line graph in . (2013)  reportedDifferent failure patterns of specimens are shown in PPF specimens sustain the impact force and delay sudden fracture and hence some specimens split into four parts. The failure mechanism of CS-PPF concrete is governed by the bridging effect of PPF and improvement in bond strength between cement and fibre. Intrusion of PPF increases the impact resistance and also reduces the anticipated or catastrophic failure of the samples. The fibrillated type of PPF made a networking structure to produce adequate pull-out resistance. The bonding occurs due to the filling effect and pozzolanic activity of CS. The optimum performance was achieved through the dense microstructure and the bridging effect of PPF. The hammer’s concentrated impact force acts as an inertial load on the specimen in the direction of acceleration. The sample attempts to bounce back against the applied load, but the steel ring above stops the movement. The specimens are split into two to four pieces depending upon the stress distribution. The separation of components is due to cracks forming from the point of loading to different radial directions. Fibre admixed specimens do not show complete cleavage along the path of cracks because the cracks are stitched with the fibrillated structure of polypropylene fibre. The short discrete fibres arrest microcracks due to their interconnection in tension region and reduce the friction between the fibres and cement matrix .The fibre reinforced composites exhibit higher resistance to the impact loading than the unreinforced concrete matrix . The craThe observed values of number of blows are shown in The number of impacts observed up to the initial crack for the C40P4 concrete mix at 7, 14 and 28 days is 82, 158 and 172, respectively. The control concrete, on the other hand, has 13, 64 and 84. The concrete containing 40% copper slag and 0.8% PPF (C40P4) is highly resistant to initial cracking when subjected to impact loading. The maximum resistance at first crack was 1–5 times higher than the control specimen. Impact loading is reduced in concrete containing 100% copper slag. Because CS has finer particles, the particles are crushed when impact loading is applied. Although CS has a high specific gravity, there is much less copper slag in a given volume, necessitating a high cement paste to bind the concrete matrix. Insufficient binding makes the concrete porous and less resistant to applied loading . Since C2 to make additional CSH gel, the microstructure of C40P3 in Many researchers have proved this theory in research on copper slag . At 28 dThe blows for the initial crack are increased from 2.66 to 2.91 times at 28 days, while impacts for the post-initial crack increase from 2.75 to 3.10 times. Because of the increased ductility of concrete, the difference between the number of blows at the initial crack and the number of impacts at ultimate failure increases as PPF content increases. One study revealed that for the fibre volume of 0.2%, the number of blows increased to 1.31 times [3S), tricalcium silicate  and other calcium silicate phases occurs during the hydration process. 3O4) and magnetite (Fe2SiO4) crystalline phase through XRD images [The formation of C–S–H gel from dicalcium silicate , which produces C–S–H gel and Ca(OH)2, with some Ca(OH)2 remaining as an unreacted component. The hydration of tricalcium silicate is a critical reaction in the development of concrete strength (C3S). Excess CH  is produced during the hydration of C3S and could be consumed by copper slag. More silicate ions (S) are supplied by copper slag, which reacts with CH to form more C–S–H  gel. Because of the low CaO content, copper slag shows poor cementitious properties. However, when combined with cement, it can produce high pozzolans due to the high concentrations of silica, alumina and iron oxide [2O3 and SiO2 is attributed to critical peaks in the copper slag XRD pattern. Copper slag densifies concrete microstructure due to the pozzolanic activity of silicate ions (SiO2) with Ca(OH)2. The development of strength in concrete occurs during the hydration process as a result of the condemnatory reaction of tricalcium silicate gregates . 2. 2 components.2 is the principal reason for the increase in strength and durability. Furthermore, it accelerates the hydration of cement-containing copper slag filling the pores and resulting in a dense microstructure [2 components. PPF surrounded by the hydrated products ensures proper filling of minor gaps between the fibres. The round particle shape represents the copper slag, and the lean particles illustrate the PPF present in concrete. SEM images depict that unreacted Ca(OH)2 present in the control concrete gradually disappears in successive replacement levels of copper slag. More CSH gel formation and fewer Ca(OH)2 parts are identified through those images; hence the optimum replacement is 40% of CS and 0.6% of PPF. However, for up to an 80% replacement, the impact resistance of concrete does not fall below that of the control concrete.The PPF was surrounded by reacted components, evidenced by the superior pozzolanic activity. Comparing the control concrete and concrete containing 40%, not having any unreacted Ca(OH)tructure . The micThe linear relationship between the initial cracking and ultimate failure at 7, 14 and 28 days was derived by regression analysis to analyse the interdependency of the experimental results. A strong linear relationship was proven among the N2 and N1 values. The relationships predict the number of impacts at the ultimate failure of regression coefficients 0.9302, 0.9819 and 0.9807, respectively, at 7, 14 and 28 days. Testing with more impact at the cracking level requires more hits to fail. Fibrillated PPF acts as a thread to bond the cement matrix with sharp-edged CS particles with a high specific surface area, increasing concrete’s impact resistance. PPF does not affect compressive strength, but it does increase ductility and energy absorption capacity . The preDrop weight impact testing was performed according to ACI Committee 544 and showed significant variations in result data. Identifying the first crack is difficult since it can occur in any direction and the width of the initial crack is very small and difficult to spot it visually. The number of blows is the measure of impact resistance but the number of blows may vary according to the hardened material, such as coarse aggregate or smooth cement matrix below the point of application of impact loading. The test depends upon the manual operation of holding the mass of the hammer. Most of the crack patterns propagate along three mutual perpendicular directions from the point of application of loading. However, some specimens show different patterns and some smooth surfaces subjected to testing cause variability in crack paths . The rest represents the numbers of random variables between N1 and N2, t0 is the location variable where t ≥ t0, α > 0 and β ≥ t0.Weibull distribution reliability analysis accepts reliability analysis for fatigue analysis and impact testing . The twoEquation (8) represents the probability survivorship function.t0 function is assumed to be zero. According to the minimum life the equation is revised to obtain revised survivorship probability (FRSP) as given in Equation (9).To define the minimum life of brittle concrete composite under impact and fatigue loading, the Taking natural log on both sides of Equation (9) twice, the following Equation (10) was obtained.Equation (10) can be separated as individual component of a linear equation consisting of slope and intercept Y = ln(S) known as Benard’s approximation [x is the consecutive serial number of results arranged in ascending order. n is the total number of sample points. The graph was plotted using the data set between Y = ln(R) or N2 (R) based on reliability probability can be determined using the formula given in Equation (12).The failure probability of each experimental result was substituted to the empirically derived survivorship function Fximation  given inWeibull distribution reliability analyses were executed using Microsoft Excel. The following steps are adopted to obtain the percentage of reliability on impacts obtained through the drop weight impact resistance test.The experimental observation includes the number of impacts at cracking and failure stage on 7, 14 and 28 days. The results are grouped into P0 (0.0% PPF), P1 (0.2% PPF), P2 (0.4% PPF), P3 (0.6% PPF) and P4 (0.8% PPF).The number of blows in each group was sorted in ascending order and the serial number was assigned from 1 to x where x is the respective serial number.(RSP) was calculated using the formula given in Equation (9).The failure probability FThe natural logarithm value of N1 or N2 was determined.The value of equation lnx axis and lny axis.The graph was drawn taking ln (N1 or N2) as 2 value on the graph. The equation is used to obtain the value of slope and intercept C. The points in the graph were picked to obtain a linear trendline with equation and Rβ.The slope of the trendline is taken as β and intercept C the value of The intercept C = β, FALSE). The Weibull cumulative distribution was performed using the Weibull formula. Dist  from 1.Reliability probability (R) was calculated by subtracting Revised Survivorship Probability (FThe impact strength of concrete in terms of N1 and N2 was determined using the reliability probability as given in Equation (12). The graphs were drawn between the reliability coefficient and the number of blows which are shown in The minimum regression coefficient is 0.8422 and the maximum coefficient of determination is 0.9775. The data set fitted to the linear trendline shows the regression coefficient greater than 0.8 evidencing a good prediction leading to an accurate Weibull distribution . The numEnergy absorption is the amount of work done or the amount of energy stored in the material. Materials with high energy absorption are more resistant to impact loading. Fibres are primarily energy-storing materials needed explicitly in impact loading or any other accidental loading where ductility is the primary factor. From The maximum energy absorption values in the C40P3 mix are 610.61, 814.14 and 1485.81 Nm at 7, 14 and 28 days. The energy absorption values of the control concrete at 7, 14 and 28 days were 203.54 Nm, 264.6 Nm and 386.72 Nm. The corresponding increase in percentages is 199%, 207% and 284%, which is approximately the energy absorption increased two times. Previous literature stated that the energy absorption at 7, 14 and 28 days is doubled for the fibrillated fibre reinforced concrete, which was confirmed in this experimental work  The tren−Copper slag has many potential benefits such as improving workability, increasing impact resistance and producing pozzolanic properties. Copper slag would be an exceptional substitute for fine aggregate. There is no detrimental effect detected on replacing the fine aggregate up to 80% CS. CS 40% and PPF 0.4% shows optimum replacement according to compressive strength results. The C100 group does not attain required target strength due to the free water content in the mix. The free water content is attributed to the low water absorption of CS.−PPF in CS concrete enhances the ductility, post crack performance and increases the capacity against failure compared to the mixes without PPF. A 0.2–0.6% of PPF volume fraction shows improved performance compared to 0.8% PPF. The networking structure of bonding within the fibre concrete matrix reduces the linear and lateral expansion of cracks and hence the count at first crack itself increased. Fibrillated fibre shows higher post-cracking resistance.−The impact count gradually increases up to 80% replacement of copper slag. In each batch of CS replacement there is an increasing trend of blows according to PPF content. Concrete containing 100% copper slag replaced with sand tolerated 35–47% less blows to break the specimen. C40P4 tolerated the highest number of blows of 82, 158 and 172 at 7, 14 and 28 days, respectively. Blows at initial crack increased from 2.66 to 2.91 times. The impact blows increase from 2.75 to 3.10 times over the control concrete at 28 days at ultimate failure.−2 is visualized in SEM images. The microstructure of concrete evidences homogeneous spread of CSH gel, pore filling effect and dense microstructure.The hydration product increases in CS mixes compared to the control concrete can be evidenced through microstructure images. Due to the excellent pozzolanic activity of CS the amount of CSH gel formation increases with each increment of CS, and thereby a reduction of unreacted Ca(OH)−Regression analysis was performed to derive a relationship between early cracking and ultimate failure. The proposed best fit of linear equations predicts the N2 values from N1 derived the regression coefficients of 0.9302, 0.9819 and 0.9807, respectively at 7, 14 and 28 days.−Weibull distribution using shape and scale parameters is suitable for distributing the variation in number of blows at initial crack and ultimate failure. The impact blow counts observed at reliability level 0.8 or greater is significantly related to the tabulated blows during experimentation.−The energy absorption values are doubled in the case of fibre reinforced proportions. Maximum values of energy absorption were found in the C40P3 mix, respectively, 610.61, 814.14 and 1485.81 Nm at 7, 14 and 28 days. At the same time, the energy absorption values of the control concrete at 7, 14 and 28 days were 203.54, 264.6 and 386.72 Nm, respectively.−The outcome of this study describes the mix proportioning of CS-PPF concrete, characterization of microstructure, crack propagation during impact loading and finally, the optimum content of CS and PPF. Since copper slag is a pozzolanic material, like fly ash, the copper slag would be an essential alternative to fine aggregate in the future. Copper slag PPF concrete can be employed to produce solid blocks, hollow blocks and precast elements. This research work can be extended to other types of concrete-like high-density concretes, self-compacting concrete, etc.Wastes generated by various industries can be used in multiple ways in the field of solid waste management. Using alternative materials for cement and fine aggregate reduces consumption and increases natural resource conservation. The experimental part of the study includes the testing of concrete under impact loading according to ACI drop weight method and the analytical part of the study considers the variability of results obtained during experimental work and arriving at normalised values for number of blows using Weibull distribution. At 40% of copper slag replacement, the impact resistance is high at 0.8% PPF and energy absorption was a maximum at 0.6%. Hence, optimum replacement of copper slag is 40% and optimum volume fraction of polypropylene fibre is 0.6–0.8%. This research work brings the following conclusions:


Antimicrobial resistance (AMR) is a significant problem in global health today, particularly in low- and middle-income countries (LMICs) where antimicrobial stewardship programmes are yet to be successfully implemented. We established a partnership between AMR pharmacists from a UK NHS hospital and in Ho Teaching Hospital with the aim of enhancing antimicrobial stewardship knowledge and practice among healthcare providers through an educational intervention. We employed a mixed-method approach that included an initial survey on knowledge and awareness before and after training, followed by qualitative interviews with healthcare providers conducted six months after delivery of training. This study was carried out in two phases in Ho Teaching Hospital with healthcare professionals, including pharmacists, medical doctors, nurses and medical laboratory scientists. Ethical approval was obtained prior to data collection. In the first phase, we surveyed 50 healthcare providers, including nurses (33%), pharmacists (29%) and biomedical scientists (23%). Of these, 58% of participants had engaged in continuous professional development on AMR/AMS, and above 95% demonstrated good knowledge on the general use of antibiotics. A total of 18 participants, which included four medical doctors, five pharmacists, four nurses, two midwives and three biomedical scientists, were interviewed in the second phase and demonstrated greater awareness of AMS practices, particularly the role of education for patients, as well as healthcare professionals. We found that knowledge and practice with AMS was markedly improved six months after the training session. There is limited practice of AMS in LMICs; however, through AMR-focused training, we demonstrated improved AMS skills and practice among healthcare providers in Ho Teaching Hospital. There is a need for continuous AMR training sessions for healthcare professionals in resource-limited settings. Antimicrobial resistance (AMR) is a significant problem in global health today. It is severe in low- and middle-income countries (LMICs), where the burden of infectious diseases is much higher. There is limited information on the extent of this problem in these settings. Global mortality projections due to AMR in the next few decades show that the greatest impact will be in Africa and Asia . InapproStaphylococcus aureus (MRSA) has also been documented [Widespread AMR has been documented in Ghana in national reports and published research . Ghana’scumented . Ghana’scumented . Reportscumented . There icumented ,7.The Tropical Health and Education Trust (THET), together with the Commonwealth Partnerships for Antimicrobial Stewardship (CwPAMS) developed and funded a partnership model between United Kingdom (UK) National Health Service (NHS) hospitals and African partners . The goaThis study was conducted in Ho Teaching Hospital, which is located in the Volta region of Ghana. The hospital is a tertiary care hospital and serves as a teaching hospital with a staff strength of about 1200, 306 bed spaces and 14 wards. Ghana is low- and middle-income country located in the sub-Saharan part of West Africa. Ghana has an established National Health Insurance Scheme (NHIS) that provides a broad range of healthcare services to Ghanaians through district, mutual and private health insurance schemes .We employed a bottom-up approach with a mixed-method study design ,12. ThisBox 1Topics included in the AMR/AMS Training ProgrammeAMR/AMS—Antimicrobial Resistance/Antimicrobial StewardshipAwaRE—Access Watch, REserveWHO—World Health OrganisationTraining block 1AMR/AMS—definitions; global concern, WHO position, United Kingdom’s and Ghana’s positionsAWaRE lists and what they meanExamples of AMS activities—using specific case scenarios and different infrastructures, e.g., paper prescribing systems vs. electronic systemsGlobal Point Prevalence SurveyIntroduction to Quality Improvement and Behavioural Change theoriesTraining block 2Infection prevention and controlFeedback and review of results from GPPS 1Consider areas for change; apply QI methodology and Behavioural Change theoriesConduct Global Point Prevalence Survey 2Training block 3Enabling pharmacists as AMS leaders and champions—role of clinical pharmacists/advanced pharmacy practiceFeedback and review of results from Global Point Prevalence Survey 2Reiterate QI approaches and Behavioural Change theoriesConduct Global Point Prevalence Survey 3For phase 1, we designed a data collection tool  to retriData collected from the initial pre- and post-training surveys were entered into and analysed using the IBM Statistical Package for Social Sciences (SPSS) version 22. Results were presented using basic descriptive frequencies. All interviews were transcribed verbatim, and transcripts were read repeatedly and then coded individually to identify similarities and differences. All transcripts were coded and reviewed alongside the generation of a coding frame. Codes were also mapped unto the Behaviour Change Wheel (BCW) framework based on the influence of the model of Capability, Opportunity and Motivation on Behavioural outcomes (COM-B) see  below 1. SimilarEthical approval was obtained via an ethics application made to the research and ethics committee of the University of Health and Allied Sciences. Ethics reference number: UHAS-REC A.9  18–19 , pharmacists (29%) and medical laboratory scientists (23%) as shown in Up to 58% of the participants engaged in CPD with topics on AMR/AMS, and above 95% demonstrated good knowledge on the general use of antibiotics. While many were familiar with terms such as antibiotic resistance and antimicrobial resistance, more than half were not conversant with antimicrobial stewardship, superbugs and AMR capacity building. However, the proportions demonstrating good knowledge of AMR/AMS increased after the training .The participants demonstrated good knowledge of antibiotic use, which further improved after the training sessions. The majority of the participants either strongly agreed or agreed with the statements on antibiotic use .Knowledge about AMR was low among the HCPs. Less than 50% of the respondents demonstrated good AMR knowledge in some of the questions, and this improved considerably after training .More than 80% of the participants agreed that patients’ clinical conditions and microbiology results were key determinants for antibiotic prescriptions, while more than 97% agreed that there was a lack of effective diagnostic tools and that inappropriate prescriptions of antibiotics still exist. About half of the participants confirmed that there were no specific prescription policies and protocols and that the antibiotics available in the facility were unable to treat some infections. The national Standard Treatment Guideline (STG) is the most consulted reference when prescribing antibiotics, followed by the British National Formulary (BNF). Over 90% of the participants agreed that obtaining local antibiotic resistance profiles and changing the attitudes of prescribers and patients will reduce unnecessary antibiotic usage.For the second phase, we interviewed a total of 18 participants, which included four medical doctors, five pharmacists, four nurses, two midwives and three biomedical scientists. Among the participants were 10 males and eight females, with ages ranging from 27 to 56 years.The majority of the interviewed participants confirmed that the training on AMR/AMS was very helpful and increased their understanding of AMR. This, in turn, led to changes in their practice, such as reduced empirical prescription of antibiotics and more detailed counselling for patients on antibiotic use.The healthcare providers across different specialties explained that they felt more confident carrying out AMS roles after the training. The nurses were competent in antibiotic drug administration and acted as patient advocates to question the antibiotics being prescribed. The pharmacists were also competent in delivering AMS roles and providing information on medications for the rational prescription of antibiotics. Both nurses and pharmacists could support antibiotic prescription decisions, especially when they involve junior doctors.The interviewed participants reported general overuse of antibiotics in Ghana with highly empirical and broad-spectrum prescribing. Factors that contribute to this observed practice with antibiotics include a lack of continuous training for prescribers and other healthcare providers (HCPs), poor compliance with guidelines, limited diagnostic services, staff shortages, pressure from patients and the influence of drug companies. To date, there have been no interventions put in place to improve antibiotic use in the hospital in this study.Commonly prescribed antibiotics include cephalosporins, penicillin, metronidazole, ciprofloxacin, erythromycin, amoxiclav and cefazolin. All of these antibiotics are in the list of essential medicines and are available in hospital formularies in both branded and generic forms. The common indications requiring antibiotic prescriptions include urinary tract infections (UTIs), respiratory tract infections, gastrointestinal tract (GIT) infections, sepsis, sexually transmitted infections (STIs) and surgical prophylaxis. There are standard treatment guidelines; however, the disease type, cost, drug availability and severity of infection are all factors that affect the choice of the antibiotic drug being prescribed.Recommended strategies for improving antibiotic use and the barriers in implementing these AMS interventionsThe respondents highlighted some recommendations for improving antibiotic use, such as including education and training for prescribers, improved labs for microbe-specific treatment, purchase of lab items for testing, antibiotic use checks/audits, employment of more staff to build the workforce and development of local policies. The main barriers to this will be failure to enforce laws and limited funding in healthcare.From the interview data, the current AMR behaviours that we saw, such as broad-spectrum and highly empirical prescription of antibiotics, fall on inherent local factors, including the lack of continuous training, limited laboratory services and lack of local policies. In order to move forward with the desired behaviours for AMS support and practice, we need to leverage the relevant intervention functions shown on the Behaviour Change Wheel. These include training, enablement, persuasion and environmental restructuring. These functions map to the policy categories of social planning/service provision, guidelines and regulations . Some adCapability: HCPs felt more confident and empowered in contributing to AMR topics during rounds and better educating patients after the training.Opportunity: More staff can be employed to create opportunities to deliver additional AMS activities.Motivation: The training was educative, increased knowledge about antibiotic use and helped to improve the AMS practice.We were able to assess baseline knowledge of antibiotic use and AMR among health professionals in the study hospital. We were also able to demonstrate the impact of an educational intervention on knowledge and awareness of AMR. The healthcare providers described the training as educative and helpful, and they found it useful in their practice with antibiotics. The training generally increased knowledge about antibiotic use and AMR/AMS, and it led to a better understanding of different aspects of antibiotics use, including the importance of proper patient education. After the training, some self-reported changes in practice in the hospital included a reduction in antibiotic use and empirical prescription, as well as better patient counselling and education on antibiotic use. AMR training and related educational programmes for HCPs have been previously employed in different settings to improve the use of antimicrobials ,15. In aEffective antimicrobial stewardship delivery in hospitals requires a multidisciplinary team effort that includes the medical doctors, who mostly prescribe, pharmacists, nurses, microbiology teams and others. Our training included these different groups of HCPs. Pharmacists are the custodians of drugs within the hospital and can ensure safe and effective use of antibiotics by providing information to other HCPs, as well as counselling patients. Nurses are competent in antibiotic drug administration and act as patient advocates to question the antibiotics being prescribed. While there were guidelines and consultations with other colleagues, the HCPs confirmed that other resources, such as improved laboratory services and an expanded workforce, would increase efficiency in the delivery of AMS roles. The HCPs recommended protocols and guidelines, more AMR training courses, improved laboratory and diagnostic services and availability of patient educational materials in order to support the delivery of AMS in the local hospital. All of these recommendations have also been identified in earlier studies as effective strategies for long-term sustenance of antibiotic stewardship programmes in LMICs ,18,19.The HCPs perceived that there is generally irrational overuse of antibiotics in Ghanaian hospitals, citing the broad-spectrum and empirical prescription of antibiotics. Factors contributing to the irrational use of antibiotics in Ghana include a lack of continuous AMR training, poor AMR knowledge, limited diagnostic services, understaffing and pressure from patients and pharmaceutical companies. This is consistent with other findings reported in Ghana ,20,21.Broad-spectrum antibiotics, including penicillin, cephalosporins, aminoglycosides and metronidazole, are commonly prescribed. Common indications for which antibiotics are prescribed include respiratory tract infections, UTIs, STIs and GIT infections. Others include typhoid and surgical prophylaxis. In the study hospital, antibiotics are prescribed in both branded and generic forms, but mostly as generics, and they are in the EML and hospital formulary. Similar indications for antibiotic use have previously been identified in Ghana ,9,22,23.Presently, there are standard treatment guidelines in the hospital to guide antibiotic use. Most HCPs employ the use of guidelines as often as they need to when dispensing, prescribing or administering antibiotics. While patients can request antibiotics, they have no influence on the decisions on if they eventually get an antibiotic or which antibiotic should be prescribed for and dispensed to them. In addition to laboratory diagnostic reports, the following factors are considered in choosing antibiotics for a patient: the disease and its severity, the cost of the antibiotic and the availability.Our study had several limitations. First, only a small subset of HCPs from the study hospital were involved in the AMR training programme. The impact of the training would be more effective if a larger cohort had been trained. Secondly, while improvements to knowledge and awareness was assessed immediately after the training, we relied on self-reported changes in practice to assess the impact. This assessment may be subject to reporter bias . HoweverThe findings of this work have several implications for practice and policies. Given the factors underpinning current antimicrobial use patterns, there is a need for dedicated AMS staff to promote and oversee AMS activities in the hospital. Routine training and AMR-focused workshops should be organised for healthcare providers to reinforce and sustain AMS practices. According to data from the GPPS results, local AMS policies should be developed to guide antimicrobial use in the local hospital context. National and international treatment guidelines should be adapted and tailored for relevance and use in the local settings. There is a need for further research to evaluate the impact of the AMS team on practice and to identify further parameters for long-term sustainability.AMR is still a budding public health challenge across the globe, and especially in low-income settings. AMS practice is still in infancy in these settings. We demonstrate how expertise from developed and advanced settings can be leveraged to move AMS practice forward. The findings from this study show that continuous AMR training for healthcare professionals can increase knowledge and awareness, spur behavioural change to improve practice and build momentum for sustainable AMS programmes.