The natural aggregates are one of the main components in the production of concrete. Although deposits of natural aggregates lie on the earth’s surface or at low depths and belong to common deposits, the shortage of aggregate, especially natural sand, is presently observed in many countries. In such a situation, one is looking for other materials that can be used as a substitute for natural aggregates in mortars and concrete production. This paper presents the results of an experimental investigation carried out to evaluate the potential usage of waste basalt powder in concrete production. For this purpose, the waste basalt powder, which is a by-product of the production of mineral–asphalt mixtures, was substituted with 10%, 20%, and 30% sand replacement. In the experimental program, the workability, compressive strength, water transport properties, and microstructural performances were evaluated. The results showed that the production of concretes that feature a strong internal structure with decreased water transport behavior is possible with waste basalt usage. Furthermore, when waste basalt powder is used as a partial sand replacement, the compressive strength of concretes can be increased up to 25%. According to the microstructural analyses, the presence of basalt powder in concrete mixes is beneficial for cement hydration products, and basalt powder substituted concretes have lower porosity within the interfacial transition zone. The economic development of the country is reflected, among other things, in the increasing demand for construction projects, and thus the increased production of construction materials. As a result, the demand for materials for construction projects is constantly growing, and the limitations resulting from the need to protect the environment significantly reduce the range of natural resource deposits that can be used for their production. Currently, the most frequently used building materials in the world are cement composites, among which the dominant role is played by structural concrete. One of natural raw materials used in the production of cement composites are natural aggregates.The production and utilization of aggregates in Europe is about 4 billion tons per year, most of which, i.e., 91% comes from natural deposits . Due to In such a situation, one is looking for other materials that can be used as a substitute for natural aggregates in mortars and concrete production. As a partial substitute of fine aggregate, i.e., sand, the blast furnace slag and fly ash can be used. For this, there are many experimental studies available in the literature.Bilir  investigBilir et al.  reportedThe rock dust, which is a by-product obtained from the production process of crushed-stone aggregates, is another well-known powder material to be used in concrete. During rock extraction and mechanical processing, and due to their sorting, large quantities of waste material are produced in the form of rock dust. Similar dust waste is produced during the drying process of the aggregate used for the production of mineral–asphalt mixtures and at stonemason facilities. The storage of this type of fine material poses serious environmental problems. Dust released to the atmosphere significantly contributes to the accumulation and harmful dispersion of fine solids in air, water, and soil ,12.The chemical and mineral composition of dusts is the same as of the bedrock from which they originate. This makes them suitable for the production of cement mortars and concretes as a partial substitute of fine aggregate or even cement. Not only will it reduce the cost of construction production, it will also make the management of this waste more efficient. Such waste utilization is consistent with the principle of sustainable development that assumes an efficient management of non-renewable (consumable) natural resources and their replacement with recycled waste substitutes.Most authors believe that the introduction of rock dust as a replacement for the part of sand contributes to the improvement of the mechanical properties of mortars and cement concretes  as well Abdelaziz et al.  studied The improvement of properties of cement composites with rock dust additives is primarily related to the filler role of rock dust. The operation mechanism of chemically inert dust neither depends on the type of rock material the dust originates from nor its chemical composition ,32. TherThe use of waste materials in the production of cement composites, the properties and evaluation criteria of which have not been specified in the standards, requires a comprehensive analysis and evaluation of the properties of mortars and concretes produced with their use. Despite the growing interest in the use of various rock dust types in concrete production, many problems still remain unexplained. There is no literature related to basalt dust utilization as a partial sand substitute in concrete. The scientific goal of the research presented in the paper was to determine the effect of the basalt dust additive, partially replacing sand, on the properties of concrete. The influence of basalt dust on the technological properties of concrete mixtures, including the compressive strength, water absorption, permeability, and microstructure of hardened concrete with basalt dust additive were analyzed. The results of research on the concrete mechanical properties presented by the authors in this paper are consistent with those of other scientists who analyzed the influence of rock dusts of different mineral origin  on concrete properties. Moreover, the presented analyses concerning the influence of basalt dust on the porosity and microstructure of the cement matrix supplement the knowledge deficiency, especially with regard to basalt dusts used in concrete as a sand substitute.Waste basalt powder generated in the production process of asphalt mixtures with basalt aggregate was used. During the drying of the mineral aggregate, exhaust fumes leave the dryer with various powder particles. A coarser fraction of waste powder is collected in a special separator, while a very fine fraction is retained in a dryer filter. Asphalt mixture production leads to the formation of rock powder in an amount of about 5% of the aggregate mass used to produce the asphalt mixture. This very fine material is treated as a waste.2/g.The chemical composition of the basalt powder used in this study is presented in Basalt powder particles have a rough surface and an angular shape (the scanning electron microscope SEM image (Scanning Electron Microscope (SEM) Quanta 250 FEG by FEI , equipped with the system of chemical content analysis based on the energy dispersion of the X-ray using Energy Dispersive X-ray Spectroscopy  by EDAX) is presented in 2/g. As a coarse aggregate (CA) , the gravel of the group of fractions 2/16 was used, and as a fine aggregate (FA) , river sand  was used. In order to obtain the desired workability of concrete mixtures, the high-range water-reducing (HRWR) admixture was added.The concrete mixtures were prepared with the use of ordinary Portland cement CEM I 42.5R . To analyze the effect of basalt powder on the properties and microstructure of concrete, four concrete mixes were prepared. The reference concrete, i.e., concrete without waste basalt powder, was named C0, and the concretes with different amount of basalt powder replacing 10%, 20%, and 30% of the sand by mass were named C10, C20, and C30, respectively. The comparison between the properties and microstructure of reference concrete without basalt powder and concretes containing different amounts of waste basalt powder was made. The composition of the concrete mixtures is presented in To analyze the technological properties of concrete mixtures, the concrete slump test according to European Standard EN-12350-2:2011 was performed. Maintaining the same consistency and similar workability level of each concrete mixture was assumed, therefore with increasing basalt powder content, the high-range water-reducing admixture amount was increased.To assess the influence of different amounts of basalt powder on the physical properties of concrete, the compressive strength, permeability, and water absorption were analyzed. Compressive strength and permeability were conducted according to European Standards EN-12390-3:2011 and EN-12390-8:2011. The compression tests were performed using a computer-controlled test machine of 3000 kN capacity. The hardness value of the compressive test machine loading heads is 550 HV 30 (HRC 53), which conforms to the EN12390-4. For tests, the loading rate was selected constant as 0.5 MPa/s. The permeability of concrete was determined with a measuring device designed to determine the depth of water penetration in hardened concrete specimens under pressure. Research was conducted in accordance with the procedure set out in EN 12390-8. The measuring device enables the transfer of water pressure to the test area and its current indications. Water absorption was determined based on the relative mass loss of samples dried up to constant mass compared with samples fully saturated with water. Cube specimens 100 mm × 100 mm × 100 mm and 150 mm × 150 mm × 150 mm (for permeability determination) were prepared for each concrete, i.e., the reference concrete and concretes with waste basalt powder. A laboratory mixer was used to prepare concrete mixtures. After placing in the molds, concrete specimens were consolidated in two layers by using mechanical vibration. Until demolding, all specimens were kept covered in a chamber at controlled temperature 20 ± 2 °C for 24 h. After demolding, specimens were stored in water until testing. The testing of compressive strength was conducted at 7, 14, 28, 90, 180 and 360 days, the testing of permeability was conducted at 28 days, and the testing of water absorption was conducted at 28, 180, and 360 days.In order to determine the effect of basalt powder on the cement matrix microstructure, the scanning electron microscope (SEM) observation and energy-dispersive spectroscopy (EDS) analysis were performed. SEM analyses were performed with Quanta 250 FEG by FEI  instrument, equipped with the system of chemical content analysis based on the energy dispersion of the X-ray using Energy Dispersive X-ray Spectroscopy  by EDAX.). Fractured samples were specially prepared. The phases presented in the interfacial transition zone and bulk hydrated cement paste were identified based on EDS analysis.The partial replacement of sand with basalt dust leads to a change in two parameters of the analyzed concrete, i.e., the particle size distribution of the aggregate and rock material . The introduction of basalt dust into the concrete mix in exchange for the corresponding sand dust fraction allows maintaining the same screening curve of the aggregate mix and analyzing the impact of the type of rock material on the properties of concrete. However, in such a situation, it is difficult to talk about the physical effect of the additive, i.e., the effect of the filler, because the sand dust fraction is replaced with the same dust fraction. The addition of mineral dust as a substitute exclusively for the fine aggregate dust fraction will affect the properties of concrete when this additive has a clear activity in relation to the solution in the pores of the hardened cement paste. Conducting research with the substitution of sand with basalt dust allowed, first of all, to analyze the influence of aggregate mixture sealing on the properties of mortars and concretes.The change in concrete mix consistency, measured with a slump cone test, when the level of sand substitution with basalt dust at constant and variable fluidizing admixture content increases is presented in The results of the conducted tests show that a constant content of fluidizing admixture causes the slump cone test to vary from 140 mm, in a mixture without basalt dust, to 40 mm when 30% of sand is replaced with dust. This denotes the change of the concrete mix fluidity from an S3 to S1 consistency class according to European Standard EN-206:2016. The decreased workability of concrete mix with basalt powder addition is attributed to the greater compactness of the concrete mixture. As a result of the significant sorptivity of basalt powder, water is absorbed by its particles when mixing, which leads to a workability reduction of the concrete mixture . Basalt When modifying the concrete composition, it was assumed that the same consistency of concrete mixture, characterized by the slump cone (or Abrams cone) test, was maintained within 140 ± 10 mm. Therefore, as sand was gradually replaced with basalt dust, it was necessary to increase the amount of high-range water-reducing (HRWR) admixture. At 30% basalt dust content, the fluidizing admixture content has more than doubled compared to the reference mixture.3 and is higher than sand density (2.65 g/cm3), which is the reason why the density of the concrete mixture increases with the dust share increase in the sand mass.The results of studies on the influence of basalt dust on the properties of concrete mixtures with constant consistency with an increasing amount of basalt dust replacing sand are presented in The introduction of dust material into the concrete mix reduces bleeding . The conObtained results clearly indicate the positive influence of basalt dust as a sand replacement on the concrete strength . With thThe greatest strength increase in relation to the reference concrete, i.e., 19%, 24%, 25%, and 23% was reported respectively after 14, 28, 90, and 180 days of hardening, when replacing 30% of sand with basalt dust. Then, in the case of early 7-day strength, the highest 13% increase was obtained in concrete with 20% basalt dust additive. Concrete strength with basalt dust after 360 days of hardening does not significantly differ from that of the reference concrete. It is worth mentioning that concrete with 10% basalt dust additive gained 28-day reference concrete strength just after 7 days and 90-day reference concrete strength after only 14 days.The beneficial effect of basalt dust on the mechanical properties of concrete is connected with the physical effect of this additive, i.e., with the filler effect. Basalt dust grains fill empty spaces (pores) between sand grains and coarser aggregate. This results in a higher tightness of the aggregate composition, a more compact cement matrix microstructure, and thus lower porosity and higher material strength ,33. FromThe introduction of basalt dust has contributed to an increased level of active centers where it is possible to crystallize hydration products, especially the C–S–H phase, which also has an influence on the increased mortar strength. Cement grains, electrostatically charged differently, tend to attract one another in water slurry, resulting in aggregate creation (flocculation). In this case, water is not able to freely penetrate all the space between cement grains, and not all cement particles are effectively used in the hydration process. Microfiller introduction causes a greater dispersion of cement grains, which contributes to the accelerated hydration of clinker phases and therefore a faster strength increase ,33.Basalt dust additive has little effect on the water absorption of concrete. The mass absorption of all tested concretes did not exceed the value of 4.5% and decreased with hardening time . After 2It is worth mentioning that the concrete absorption was determined without evaluating the actual volume of water-saturated material, which may significantly affect the test results. This specific test method uses the mass of water absorbed by the concrete to refer to the mass of the whole dried sample and not only to the mass of the volume of the water-saturated material. It may have a particular effect when determining the absorption of concrete after 28 days of hardening. A longer sample hardening period in wet conditions means a larger volume of water-saturated samples. Therefore, it can be considered that a more reliable assessment of the impact of basalt dust on the concrete absorption can be performed after a longer hardening period, i.e., after 180 and 360 days of concrete cure.The research showed that the penetration depth of pressurized water in all analyzed concretes is very low and is between 10 and 17 mm . Here, 5Although all concretes feature low permeability, the water penetration depth in concrete with basalt dust additive is slightly lower in comparison with the reference concrete. The pore system has a significant influence on the permeability of concrete. The reduction of permeability is strongly influenced by the pore system. The share and structure of continuous capillary pores is of the greatest importance here . The intIn order to analyze the microstructure, porosity tests of cement mortar samples were performed. Basalt dust was a sand substitute in the amount of 10% and 20%. It was found that as the basalt dust share increases, the total pore volume and porosity decreases. Basalt dust additive reduces mortar porosity in the capillary pore range. On the other hand, the share of fine pores below 50 nm in diameter and of gel pores below 10 nm is significantly increased . This haFrom SEM observation and EDS analysis, it was found that products of hydration, the C–S–H phase in particular, crystallize on basalt dust particles. Very fine particles of basalt dust act as crystallization centers and provide additional areas where C–S–H nuclei can settle .In cement paste without basalt dust additive, large hexagonal portlandite plates were identified , while tThe presented SEM image of a concrete fracture with basalt dust additive  containsBasalt powder affected the workability of fresh concretes. When mixing water is kept constant in concrete mixtures, the workability of concrete mixes decreased with the increase in substitution ratios of basalt powder. When the basalt powder replacement rate was increased to 30%, a 71% decrease in consistency occurred . For the production of basalt powder substituted concrete with constant consistency, HRWR should be increased based on the increasing rate of basalt powder substitution. Thus, the consistency of concretes can be maintained by increasing HRWR based on the increase of basalt powder. This increase in water demand can be attributed to the relatively greater surface area of basalt powder.The amount of air in the reference mixture, which is 4.1%, decreased up to 2.5% with 30% basalt powder addition. This indicates that the use of basalt powder reduces the void rate in the concrete. In addition, concrete densities also increased inversely proportional to the amount of air and supported the improvement in the internal concrete structure. This result can be related to the higher density of basalt powder compared to the sand used in the mixture. This means that the concrete internal structure has become more compact and the impermeability has increased with basalt powder substitution, and thus a better concrete internal structure has been obtained.The compressive strength of concretes increased in all mixes based on the concrete curing age. In addition to this well-known result, the substitution of basalt powder instead of sand increased the compressive strength of all substitution rates and curing periods. In concrete mixes containing basalt powder, the increase in compressive strength has been achieved up to 25%. The increase in compressive strength, which is an expected result due to the decrease in the amount of concrete air and the increase in density, can be explained by the fact that the internal structure of the concrete becomes more compact as a result of basalt powder usage.Although there is no significant relationship between water absorption and basalt substitution rate, very clear information was obtained from the pressurized water penetration depth data. As it is well-known, the pore system has a significant influence on the permeability of concrete. According to the achieved findings, it can be concluded that the relatively small particles of basalt dust blocked the continuous capillary pores and thus reduced the concrete permeability.Microstructural analyses showed that the presence of basalt powder in concrete mixes is beneficial for cement hydration products. According to the SEM observation and EDX analysis, very fine particles of basalt dust acted as crystallization centers and provided additional areas where C–S–H nuclei can settle. It was observed that the basalt powder well adhered to the hydrated cement paste, and the portlandite crystals did not appear in large quantities between the basalt powder and the C–S–H gels. Contrary to reference mixes, the lack of large portlandite crystals was observed in the microstructures of basalt powder-substituted concrete. This observation indicates that basalt powder-substituted concretes have lower porosity through the interfacial transition zone. This is the result of the reinforcement effect of basalt powder on ITZ .This study discusses an experimental program carried out to investigate the effects of basalt powder replacement on the physical, mechanical, and microstructural properties of concretes. The following conclusions can be drawn based on the results of this study:As a result, the experimental study showed that in addition to improving some physical, mechanical, and microstructural performances of concretes and reducing the usage of natural raw materials, using basalt dust leads to the consumption of this industrial waste, thus providing a twofold benefit.This study may be extended with new experimental studies related to concrete durability and the steel–concrete bond performance of basalt dust-substituted concretes to better understand the potential of basalt powder usage in concrete production.


A side effect of using modified polycarboxylates to liquefy a concrete mix is additional pores in the concrete. They change the air void system in hardened concretes, and can be used to evaluate the freeze–thaw resistance of concretes. The purpose of this study is to determine the impact of the abovementioned quantitative and qualitative parameters on the freeze–thaw resistance of concretes. The research program was performed on eight sets of air-entraining and non-air-entraining concretes with a variable content of superplasticizer based on modified polycarboxylates. The basic composition of and air-entraining admixture content in the air-entraining concrete mixtures were held constant. Pore structure tests were performed according to EN 480-11. Scaling resistance was determined according to PKN-CEN/TS 12390-9. The results showed that as the content of modified polycarboxylates increased, the pore structure was adversely affected, and, consequently, the air void parameters deteriorated. At the same time, the freeze–thaw resistance of the non-air-entraining concretes decreased. The pores sizes also changed. As the fluidity increased, the specific surface area decreased, and, consequently, the spacing factor increased. The air-entraining concretes, despite the deterioration in the pore structure due to the modified polycarboxylates, were found to be very good quality concretes after 56 freeze–thaw cycles in the presence of 3% NaCl. Ensuring that concrete is resistant to frost is one of the most important durability issues with concrete, and has resulted in numerous research works in this field ,4,5,6,7.The use of thawing salts speeds up the destruction of concrete due to a freeze–thaw cycle. This destruction is most often manifested by chipping on the concrete’s surface. Even when the structure is destroyed due to the very strong effects of a freeze–thaw cycle when thawing agents are used, such destruction only covers the hardened cement paste’s surface layer, which has a thickness of several millimeters ,6,8,9,10The durability of the concrete’s top layer determines its resistance to scaling. Apart from maintenance, air-entraining and a correspondingly low water–cement (w/c) ratio are the key indicators. Air entraining (AE) improves the workability of a concrete mix, and also reduces sedimentation by making air bubbles retain the form of a suspended solid. Thus, AE increases frost resistance in two stages: it reduces bleeding; and, after scaling occurs, the top layer protects the concrete against the volumetric effects of freeze–thaw cycles. Reducing bleeding is very important because it can decrease the w/c value and, as a consequence, increase the strength of the top layer, resulting in protection against surface scaling ,13,14,15The most important parameter of concrete mixes is the w/c ratio, which is responsible for their material properties and determines their durability and strength. In particular, lowering the w/c value reduces bleeding, increases strength, and consequently increases resistance to scaling. To ensure that concretes are resistant to scaling, concretes with a w/c ratio ≤ 0.30 should not have AE ,2,6, whiThe AE meter is the proper air-entrained structure for hardened concrete, and protects against freeze–thaw cycles if ice forms in an air pore and is compressed by the surrounding matrix ,16. The 300), total content of air in hardened concretes (A), and specific surface area (α), take into account all of the pores in the concrete in the range of 10–4000 µm. This not only includes pores from air entraining, but also pores caught accidentally and pores that are a side effect of the use of superplasticizers (SPs) [According to EN 480-11 , the parrs (SPs) ,24. The rs (SPs) ,26,27. Srs (SPs) .The results of tests on the impact of SPs on the air void parameters (AVPs) of hardened concrete showed  that liq300 ≥ 1.5% [Khayat  showed t0 ≥ 1.5% ) are notThe impact of the side effect of SP use in the form of additional pores, as a consequence of shaping the air void structure (AVS) and the relationship with the concrete’s resistance to freeze–thaw cycles, has been the subject of many studies. These studies have particularly been concerned with SCC concretes with a very complex system of compatible admixtures and rheological problems ,39,40,41To unambiguously determine the effect of an SP based on an MP, which is used to regulate the consistency of the concrete mix, tests were carried out on NAEC and AEC mixes and hardened concretes with the same basic recipe that differed only in the content of SP. The dose of AEA was held constant in the air-entrained mixtures.We adopted commonly used SPs and AEAs in the research program to increase builders’ and engineers’ awareness and knowledge of the impact of SPs on a concrete’s resistance to scaling and its assessment in the light of AVPs. This research is particularly relevant to regions with a cold climate, as the concretes used in these regions must have adequate resistance to freeze–thaw cycles. Since an SP affects both the AVS in hardened AEC and NAEC and their resistance to scaling, it is important to determine its effect on both a concrete’s features and the relationships between them.3 and a Blaine fineness of 3849 cm2/g, which meet the requirements for reference concrete in accordance with EN 480-1 [Portland cement CEM I 42.5R with a density of 3.1 g/cmThe properties of the admixtures are given in The percentage content of SP and AEA was calculated in relation to the mass of the cement. The amount of SP was determined experimentally to obtain the consistency classes S1–S4. The amount of AEA in the air-entrained mixtures was held constant. All tests were conducted at laboratory temperature.Eight NAEC and AEC mixes were made. The basic recipes, i.e., the content of cement, water, and coarse and fine aggregate, were the same . In the 3. Coarse and fine aggregate and cement were mixed for 0.5 min, then some mixing water was added and the mixture was mixed for another 0.5 min. SP was added along with 2 dm3 of water and the mixture was stirred for 1 min. Finally, in the AEC mixtures, an AEA with 2 dm3 of water was added and the mixtures were mixed for 2 min. The total mixing time was 2 min for NAEC mixtures, and 4 min for AEC mixtures. Test samples were demolded after 24 h and stored in a chamber at 20 ± 2 °C and a humidity of 95 ± 5% in accordance with EN 12390-3 [The mixtures were made in a horizontal plan mixer with a volume of 0.1 m 12390-3 .At the concrete mix stage, consistency was tested by the Slump test method in accordance with EN 12350-2 , densityA scaling resistance test was carried out in an automatic chamber for the freezing and thawing of samples according to CEN/TS 12390-9:2016 . The tes56 < 0.1 kg/m2;very good quality concrete: m56 < 0.2 kg/m2 or m56 < 0.5 kg/m2 and m56/m28 < 2 or m112 < 0.5 kg/m2;good quality concrete: m56 < 1.0 kg/m2 and m56/m28 < 2 or m112 < 1.0 kg/m2; andacceptable quality concrete: m56 > 1.0 kg/m2 and m56/m28 > 2 or m112 > 1.0 kg/m2.unacceptable quality concrete: mTo assess the resistance of concrete to scaling, the criteria from the Swedish standard of the Borås method SS 137,244  were useCompressive strength and density were determined after 28 days in accordance with EN 12390-3  and EN 1300.The AVPs were determined in accordance with EN 480-11  by means3; the densities of the AEC mixes ranged from 2470 to 2570 kg/m3. In the NAEC mixtures, the air content ranged from 1.2 to 2.9%; in the AEC mixtures, the air content ranged from 2.7 to 6.0%.The results of the concrete mix tests are given in Liquefaction of concrete mixes with the SP resulted in an increase in density and a decrease in air content in both the AEC mixes and the NAEC mixes.The results of the compressive strength and density tests are given in The results of the scaling resistance tests are given in 300 for the tested concretes are given in The AVPs A, L, α, and AIn the AEC mixes, it was not possible to observe the effect of the SP on scaling resistance, because all of the AEC mixes, after 56 cycles of freezing and thawing in the presence of 3% NaCl, showed very good scaling resistance. However, in the NAEC mixes, a decrease in scaling resistance was observed as the SP content increased . The NAEThe destruction of C2 and C3 was in the form of a spatter on the concrete’s surface and, according to the literature ,6,8,9,10As shown in In order to determine the air void system in hardened concrete that will protect against freeze–thaw cycles ,16, FiguThe use of constant AE content in AEC mixtures CA1–CA4  resulted−1. The obtained α values in all NAECs, despite the variable resistance to scaling in the C1-very good to C4-unacceptable range, did not exceed 24 mm−1. Suggesting according to the guidelines [2 = 1) with increasing SP content. Which, with a slightly changing total air content A, confirms that SP causes an increase in the content of large pores. This is the effect of joining small pores into large ones due to a decrease in viscosity resulting from liquefaction of the concrete mix. In AEC CA1–CA3 the value of α exceeded the recommended 24 mm−1. Only in CA4 concrete the value of 17.45 mm−1 was obtained, with very good resistance to scaling. Therefore, the recommended level of α [idelines  no resisvel of α  has not 300 as the SP content increases are described by linear relationships  are not correlated with the tested freeze–thaw resistance in the case of ordinary concretes.The obtained AVP values confirm the literature data on the impact of SPs based on MPs on the decrease in pore content favorable for freeze–thaw resistance (entrained air) as against unfavorable pore content (entrapped air). They also confirm that AVPs take into account both air-entraining pores and pores that are a side effect of SP action ,24. As aAll AEC mixes, after 56 cycles of freezing and thawing in the presence of 3% NaCl, showed very good scaling resistance; therefore, no effect of SP on their scaling resistance was observed.In the NAEC mixes, with an increase in SP content and simultaneous liquefaction, the resistance to scaling decreased as a result of the top layer of the concrete being weakened and changes in the porosity structure.300.SP was found to significantly change the AVPs, particularly in the AEC mixes. It causes a significant decrease in the specific surface area, which results in an increase in the spacing factor L and a decrease in the content of micropores A300 showed the decrease in pore content favorable for frost resistance (entrained air) as against unfavorable pore content (entrapped air). They also confirm that AVPs take into account both air-entraining pores and pores that are a side effect of SP action. As a consequence, SPs shape the AVPs, whose standard values in concretes for the assessment of freeze–thaw resistance (L ≤ 0.200 mm and A300 ≥ 1.5%) are not correlated with the tested scaling resistance in the case of ordinary concretes.The qualitative analysis the impact of SPs based on MP on the AVPs: A, α, L, and A300 and SP content in both NAEC and AEC were determined and associated with scaling resistance. These relationships can be used in more complex systems to be used in projects involving air-entrained SCC and pavement concretes.The quantitative, described by mathematical equations relationships of AVPs: A, α, L, and A


A prototype is fabricated and measured to determine the scattering parameters of concrete samples. After measurements, the obtained results are used in the efficient and accurate Nicolson–Ross–Weir (NRW) method, making it possible to estimate the values of the complex relative permittivity of the concrete blocks. The sensor design is demonstrated from initial simulations to measurements for validation of the developed prototype. The obtained results for the complex relative permittivity of concrete are in agreement with those available in the literature and the difference between the simulated and measurement results for the sensor antenna resonant frequency is 4.71%. The used measurement setup can be applied to characterize different types of solid or liquid dielectric materials.A new microwave sensor is proposed to characterize the complex relative permittivity of building non-magnetic materials and used in the characterization of three concrete samples. The proposed sensor structure consists of a log-periodic planar antenna with microstrip elements tilted forward by an angle β and printed, alternately, on the top and bottom sides of a dielectric layer. The operation principle is based on the measurement of the scattering parameters S In the current scenario of mobile communications technologies, several studies have been carried out seeking to discover and minimize possible problems that may arise in the communication channels. Several studies are being carried out showing that elements positioned between the transmitter/receiver terminals severely affect the characteristics and the transmission capacity of any radio link ,2,3,4,5.Other types of sensors were developed, such as the microwave double waveguide sensors, which serve to identify small gaps between the concrete structures and the metal ,14, enabCompressive strength is one of the most studied properties in concrete. From it, the amount of load that the concrete supports and its durability are determined. However, a characteristic that affects this material is its water/cement ratio. Thus, producing a microwave sensor that can measure electrical properties ,21,22,23Identifying the properties of the concrete is clearly important but, in some structures, it is necessary to identify the reinforcement materials (fibers) that were used to produce the concrete. Therefore, the study of a microsensor based on a V-shaped resonator (VSR) was proposed as an economical and non-destructive solution to detect the type and percentage of content in fiber-reinforced concrete . In 25]25], a tiIn the last decades, a great interest has been observed from researchers worldwide in the determination of the electromagnetic properties of materials for applications in wireless communication systems. In , a step-In addition, one of the most used methods in the electromagnetic characterization of materials, including concrete, is the Nicolson–Ross–Weir (NRW) method ,36,37. TIn this context, this work proposes a new microwave sensor to be used in the characterization of the complex relative permittivity of concrete samples, based on simulated and measured values of the attenuation constant, for the propagation of electromagnetic waves. The used technique can be considered as non-destructive, as the physical structures of the samples were not changed. Some properties of the electromagnetic wave propagation and its interaction with lossy dielectric media are presented. Agreement is observed between the simulated and measured results.σ, and magnetic permeability, μ. For building materials, a medium can be identified as conductor if σ ≫ ωε and dielectric if σ ≪ ωε . Thus, for non-magnetic materials, the expression for the relative permittivity, tion (9) :(9)εr=[ to (8)) can also be expressed as phasors or complex numbers. Consequently, the use of complex numbers in Equations (3) to (5) results in obtaining the real and imaginary parts of the electrical permittivity and magnetic permeability. For non-magnetic materials, as in the case of most building materials, the relative magnetic permeability, Concrete is any product or mass produced from the use of a cementitious field . It can Composite materials have the characteristic of obtaining properties that materials alone cannot. In concrete structures, properties, such as durability, mechanical resistance, and porosity, are the most researched, usually through destructive tests. Therefore, the electrical characterization of this material becomes interesting due to the possibility that it is not necessary to extract a sample from the structure and still obtain data that are related to other properties of the concrete.In this work, the proposal was to research a concrete conventionally used in Brazil, with a 1: 2: 3 ratio and mechanical strength of 25 MPa, composed only of Portland cement, granite gravel, quartz sand, and water. In addition, it is known that the concrete hydration process and the amount of water present in its structure directly influence the properties of the concrete. Therefore, after studying the curing of the material and realizing that after 180 days of curing, the concrete already had a hydration process close to 100%, it was decided to use samples with more than 180 days of curing, stored in a place sheltered from the weather and without the presence of water.The development of a new planar antenna sensor is proposed for the electrical characterization of concrete material. The chosen characterization technique is efficient and non-destructive, requiring measurements of the propagation of an electromagnetic wave in air, between the terminals of two antennas, in the cases without and with concrete material blocks. In view of these requirements, a proposed microstrip antenna sensor was designed to achieve a directional radiation pattern, acceptable directivity, small size, low weight, low cost, and easy fabrication. Its structure is inspired by the log-periodic antenna geometry shown in N is the number of dipoles of the antenna array and the wire dipoles dimensions are lengths, nL+1, diameters, nd+1, spacings, nS+1, and positions, nR+1, for n = 0, 1, 2,…, N − 1. The angle Here, τ, and spacing factor, σ, according to the expressions shown in Equations (10) and (13), respectively, which are related to the antenna directivity, number of dipoles, N, designed bandwidth, sB, and angle In the design of a wire log-periodic antenna, its dimensions are defined by the geometric ratio, β, are printed on both sides of a dielectric FR4 substrate layer, as shown in f, scale factor, τ, and relative spacing, σ. In addition, a small number of narrow strip dipoles, N = 4, was chosen to get a small-sized antenna.In the microstrip antenna design, inspired by the log-periodic antenna geometry, narrow strip dipoles, tilted forward by an angle Two log-periodic microstrip antenna geometries were proposed and analyzed, one without a and oneTo make the design and manufacture of the proposed log-periodic microstrip antenna easy, it was fed through the straight connection of the strip dipole arms placed at the right and left side of the antenna , which wThe proposed antenna sensor geometry, shown in A prototype of the proposed antenna sensor was fabricated using microstrip technology on a FR-4 dielectric substrate, with a relative permittivity of 4.4, loss tangent of 0.02, and thickness of 1.57 mm. Thereafter, measured results were obtained for the frequency response of the antenna sensor reflection coefficient and return loss parameters.Moreover, resonance bands related to the electrical lengths of the dipoles and the effective permittivity of the used dielectric substrate (FR4), neglecting the electromagnetic coupling between the array elements, are obtained at 1.41 GHz (dipole-L1), 1.88 GHz (dipole-L2), 2.31 (dipole-L3), and 3.30 (dipole-L4). Other resonance bands are due to the electromagnetic coupling between the antenna sensor strip dipole elements.In the performed simulation, the antennas were positioned in the x-y plane, being oriented in the positive direction of the y axis, from the longest to the shortest elements. The results of the simulated reflection coefficients for the two antennas in The radiation patterns of the two antennas shown in The measurement setup was basically constituted by the proposed antenna sensor, used as a transmitter, one horn antenna, with an operating range from 700 MHz to 12 GHz, a VNA connected to the antennas and microwave absorbers, which enabled to obtain measured results of the reflection and transmission coefficients for two cases: without and with insertion of an MUT sample. As shown in As shown in μr, is 1.The results of the measurement carried out without and with the insertion of three concrete blocks placed between the terminals of the transmitting and receiving antennas were used, according to the NRW method, to (indirectly) determine the value of the complex relative permittivity of the concrete. The investigated concrete material is considered a non-magnetic material. Therefore, the relative magnetic permeability, According to Therefore, the used measurement setup is very appropriate to the considered higher frequency range and this result is related to the positioning distance of the concrete block and the distance between the antenna sensor and horn antenna, with respect to the operating frequencies.In εr = 3.39 − j0.37. The main results obtained in this analysis are shown in As shown in As shown in A new planar microwave sensor composed of a log-periodic antenna with tilted forward dipoles was developed to characterize the relative permittivity of concrete blocks. The used technique is based on the measurement in free space without and with the presence of concrete blocks samples, placed between the antenna sensor (Tx) and the horn antenna (Rx) terminals. Then, the measured results of the transmission coefficient (magnitude and phase), S21, were used according to the NRW method to estimate the concrete material complex relative permittivity.Considering the main characteristics of the proposed sensor, such as a low profile, low cost, small size, ease of manufacture, and acceptable directivity values, it has great potential and can be used to characterize different types of materials. After the measurements of three concrete samples, it was possible to extract the approximate value of the complex relative permittivity of the measured concrete.The results obtained show that, after a long curing period, the values of the complex permittivity of concrete blocks present little or no influence from the percentage of water in their composition, since the values found in the literature on the relative permittivity of liquids are higher than 50 and the values found in the measurement are lower than 5.The main contributions of this work are related to the development and application of a new planar sensor with acceptable directivity and a wide bandwidth. In addition, an accurate analysis is enabled on the determination of the electrical characteristics of dielectric materials, as these parameters are directly dependent on the frequency at which they are estimated. In addition, the use of the proposed sensor significantly reduces the complexity and cost of the setup measurement, besides being used in a nondestructive technique.As a proposal for future works, it would be interesting to investigate the application of the proposed sensor in the nondestructive characterization of other solid materials, as well as the development of other types of planar sensors.


In this study, the performance of reinforced concrete slabs strengthened using four methods was investigated under impact loads transferred from the top side to bottom side. The top and bottom sides of test slabs were strengthened by no-slump high-strength, high-ductility concrete (NSHSDC), fiber-reinforced-polymer (FRP) sheet, and sprayed FRP, respectively. The test results indicated that the test specimens strengthened with FRP series showed a 4% increase in reaction force and a decrease in deflection by more than 20% compared to the non-strengthened specimens. However, the specimen enhanced by the NSHSDC jacket at both the top and bottom sides exhibited the highest reaction force and energy dissipation as well as the above measurements because it contains two types of fibers in the NSHSDC. In addition, the weight loss rate was improved by approximately 0.12% for the NSHSDC specimen, which was the lowest among the specimens when measuring the weight before and after the impact load. Therefore, a linear relationship between the top and bottom strengthening of the NSHSDC and the impact resistance was confirmed, concluding that the NSHSDC is effective for impact resistance when the top and bottom sides are strengthened. The results of the analysis of the existing research show that the NSHSDC is considered to have high impact resistance, even though it has lower resistance than the steel fiber reinforced concrete and ultra-high-performance-concrete, it can be expected to further studies on strengthening of NSHSDC. Concrete structures are likely to be exposed to various impact loadings, for example, rock falls, terrorist attacks, and sudden crashes along their service life. When reinforced concrete slab is subjected to an impact load, it is expected to suffer an important local deflection, secondary damage caused by the occurrence of debris, and internal strength reduction. To prevent such damage, the demand for reinforced concrete with impact resistance has been increasing. Many researchers focus on new concrete members to resist impact loads, such as different reinforcement ratios and materials  ,2,3,4. TThe fiber reinforced polymer (FRP) was widely investigated in the RC members for the past few years ,22,23,24Also, studies on the strengthening of existing structure through sprayed FRP have recently been conducted ,22,23,24Recently, studies on concrete structure that incorporate fibers have been actively conducted ,31,32,33High-performance-fiber-reinforced-cement composites (HPFRCCs) exhibit high strength and are being studied and widely applied ,35,36,37This study evaluated the impact resistance properties for the following four strengthening methods: FRP, sprayed FRP, NSHSDC, and hybrid. Not only the bottom side, but also the top side were strengthened based on the existing research results ,36. The 2/g, density 3.15 g/cm3) was used, while river sand was used as the fine aggregate. In addition, crushed stones with a maximum dimension of 20 mm were used for the coarse aggregate. The details are shown in The following materials were used in the normal concrete (NC) mixture, as shown in 3 of density) and polyethylene  fiber were mixed with volume fractions of 1.0% and 0.5%, respectively, and their physical properties correspond to those of existing studies [3) is adopted as superplasticizer (SP) at cement weight ratio of 3% [The NSHSDC mixture contains silica fume and silica flour for high strength, resulting in a dense cement matrix. The steel fiber  on a ø100 mm × 200 mm specimen in accordance with ASTM C39 . In addiA total of six test specimens were tested in which both top and bottom were retrofitted with externally bonded CFS, RC sprayed with carbon fiber roving, strengthened with NSHSDC, and one in which the top was strengthened with NSHSDC and the bottom was sprayed with FRP, as well as one control RC slab and one steel fiber reinforced slab. The concrete specimens are designated as follows: the first string of characters shows the type of concrete used, where NC, NSC, SC denote normal-strength concrete, normal-strength concrete strengthened with NSHSDC, and steel fiber reinforced concrete, respectively; the second string of characters indicates the attachment of FRP; test specimens retrofitted with FRP are denoted by F, and the test specimens without FRP are denoted by NF; and the last string of characters shows that if FRP was sprayed, it was marked as S, and if not, it was not marked. For example, NCS-CF-S designated the specimen for which the bottom side is sprayed with FRP after the top side is strengthened with NSHSDC. ρrebar = 0.38%) and applied to the second layer equally in the traversal direction. In this study, the structural strengthening of concrete was conducted using dispensing FRP roving equipment manufactured by Magnum Venus Company  [CFS was attached in the x-direction of RC slab surface  . Carbon TN, USA) , and theTo overlay the NSHSDC on the specimens, 20 mm of the concrete cover was drilled, which required careful attention because the vibration during the drilling process can deteriorate the durability of the specimens. Subsequently, the NSHSDC was poured into the top and bottom sides of the concrete slab. That is, a structural member in which NSHSDC was strengthened in the compression zone (20 mm) and tensile zone (20 mm). The test specimen obtained by the strengthening method is the same as shown in As shown in Instrumentations of the test specimen involve a laser type of LVDT installed at the bottom surface for measuring the deflection. Here, the LVDT is a laser type , which has the advantage of being able to record the instantaneous displacement at a rate of hundreds of thousands of data per second. An accelerometer with a limit of 5000 g  and potentiometers with a maximum capacity of 100 mm were placed at the bottom of the specimen to measure the displacement. All output data were obtained through a dynamic data logger  and real-time impact data was acquired at a frequency of 200 kHz.As the blow progressed, the NSC-NF tended to gradually decrease the reaction force as a number of cracks occurred, but the difference between the impact force and the reaction force gradually decreased as the time lag occurred. Accordingly, all the measured reaction forces at the second blows are similar. The reaction force of the other specimens showed a slight increment by approximately 5–20% at the second blow, which increased the reaction force as the impact force applied to the reinforced concrete specimen was transferred to a support column. As shown in The experimental results are shown in max/∆res represents the degree of recovery for the structural specimen, where the higher the ratio, the higher the return for deflection [On the other hand, the ratio of ∆flection . As the flection ,46. HoweIn this study, the energy dissipation capacity of a reinforced concrete slab was calculated based on the first blow because the deflection is excessively large at the final blow, resulting in a reliability problem in obtaining the overall energy dissipation capacity . At the The support rotation angle generated in the test specimen to which the impact load is applied is a criterion for evaluating the residual performance of the structure. According to UFC-3-340-02 , one of The pattern of cracks after the experiment is shown in On the other hand, the test specimen strengthened with the sprayed FRP (NC-F-S) was found to have significant damage to the back side. The tensile reinforcement was exposed, and the damaged area was found to be wider than that of the other test specimens owing to the characteristic carbon fiber roving; although the test specimen (NC-F-S) had a high resistance to the impact energy due to the high stiffness of the reinforcement at the first blow, the accumulated impact energy during the repeated blows was determined to exceed the tensile limit of the concrete . In the The weight loss rate is an additional indicator of the residual performance after an impact load. The occurrence of concrete debris due to an impact load not only reduces the usability of the structure, but also causes environmental damage. Several studies are currently being conducted to reduce debris in specimens ,48. In tThis study evaluated the effects of reinforced concrete according to various strengthening methods. The test results showed the best impact resistance properties were shown in the NSC-NF. Furthermore, this study analyzed the two-way slabs with a similar impact energy of existing studies, as shown in (1)The NSC-NF showed excellent impact resistance and high strength. In particular, the highest strength and lowest deflection were obtained when strengthening the top and bottom sides with NSHSDC; the cracks were confirmed to spread evenly under the test specimens. This is because steel fibers and PE fibers included in the NSHSDC effectively control macro-cracking and micro-cracking and spread impact energy evenly throughout the test specimen.(2)Comparing deflection at the first blow, the lowest maximum deflection was observed in the NC-F specimen, which was 26% lower than that of the control specimen. This is attributed to the fact that CFS increased the initial stiffness. Overall, at the first blow, the carbon fiber series showed less deflection than the NSHSDC series; however, at the final blow, the ratio of maximum deflection to residual deflection decreased.(3)The crack of NSC-NF not only spread the crack evenly at the bottom but also improved the deflection capacity according to using NSHSDC, which was a hybrid using PE and steel fibers. However, strengthening with FRP and sprayed FRP cannot confirm the cracks due to the FRP adhesion. The NC-F was delaminated with the FRP, which showed the largest damaged area and exposed the tensile reinforcement. The sprayed FRP may have caused brittle fracture due to the stress concentration at the tensile section.(4)The NSC-NF showed a weight loss ratio of about 1 kg on the final blow, which is only about 0.12% of the total weight. However, the weight loss rate of the test specimen strengthened with FRP on the bottom side is approximately 2–3% of the total weight. This is due to the high ductility of the specimen as a bridging effect of steel fiber and PE fiber. Thus, the measured weight loss of the NSC-NF was smaller than that of the FRP series.(5)Compared with the previous studies, NSC-NF showed best impact resistance in the test specimens applying the strengthening techniques, but it showed disadvantage in load and deflection SFRC concrete and UHPC. However, it can be expected to further research studies on the applicability of the NSHSDC in that it can be manufactured with the thin layer while strengthening the existing concrete.This study evaluated the effects of reinforced concrete according to various reinforcement methods. Five test specimens were fabricated, including control specimens, and three strengthening methods were applied. The following results were derived from the experimental results:


The increased rates of multiresistant pathogens are a global threat to the healthcare system. As the delivery of new antimicrobials is far from addressing all resistance challenges, new alternatives to improve the current use of antimicrobials have been increasingly studied and adopted. One of the most relevant is undoubtedly antimicrobial stewardship (AMS). Antimicrobial stewardship is increasingly used to improve adherence to guidelines and clinical outcomes, to decrease antimicrobial resistance and other collateral damage and to control costs.A recent Cochrane review investigated the effectiveness and safety of AMS and found high-certainty evidence that interventions lead to more hospital patients receiving the appropriate treatment according to antibiotic policies and moderate-certainty evidence that interventions reduce the length of hospital stay without affecting safety.Several pitfalls and limitations exist that may compromise the proper conception, implementation and development of AMS for intensive care units (ICU). The purpose of this paper is to briefly address some of the main pitfalls.Clostridium difficile), and the emergence and spread of antibiotic resistance, ideally minimizing costs.-4The absence of a universal definition for AMS combined with the lack of international guidance and standards are among the many barriers to the implementation of these programs globally. The purpose of AMS is to promote the optimal/prudent/responsible use of antibiotics to optimize patient outcomes while at the same time minimizing the probability of adverse effects, including toxicity and the selection of potential pathogenic organisms , increased 65%, and the antibiotic consumption rate increased 39% between 2000 and 2015. It is expected that, assuming no policy changes, antibiotic consumption by 2030 will be 200% higher than in 2015.In fact, preserving the effectiveness of the antibiotic is a fundamental and difficult challenge in the context of a global increase and geographic convergence in antibiotic consumption.Therefore, cost containment must not be seen as the main purpose of AMS. Preserving antibiotic effectiveness is the seminal and main purpose of minimizing the induction and selection of antimicrobial resistance.-10 Most structural interventions have an enabling nature, for instance, the implementation of better and faster diagnostic methods, the use of antimicrobial resistance and antibiotic consumption surveillance systems or the use of computerized antibiotic decision support systems. With restrictive interventions, such as formulary restrictions, preapproval by senior AMS doctors and automatic stop orders, one tries to reduce the number of opportunities for inadequate prescription while enabling interventions, such as education of prescribers, implementation of treatment guidelines, promotion of de-escalation, pharmacokinetic-pharmacodynamic guided dose and dose interval and prospective audit and feedback to providers, aimed at increasing the number of opportunities and decreasing barriers for optimal prescription.There are three main kinds of AMS interventions: restrictive, enabling and structural. Restrictive interventions may be risky in some settings, such as the ICU, where prompt access to antibiotics is paramount, and in real life, potential delays in initiating antibiotic treatment were observed with some restricting interventions. They may also be detrimental to the communication between the clinical and stewardship teams. Enabling interventions consistently increases the effect of interventions, enhancing their sustainability, including those with a restrictive component (high‐certainty evidence), and they are associated with better acceptance.Both enablement and restriction interventions were independently associated with a 15% increase in compliance with desired practice, a 1.95-day decrease in the duration of antibiotic treatment, and a 1.12-day decrease in inpatient length of stay, without compromising patient safety.Antimicrobial stewardship should be a multifaceted approach in which enabling interventions are fundamental, as they are associated with better clinician acceptance and increase the effect and sustainability of other interventions. Unlike restrictive interventions, enabling does not endanger or delay access to appropriate antibiotic therapy or disrupt communication between clinical and stewardship teams. most final-year European medical students feel that they need more education on antibiotic use for their future practice as junior doctors. The proportion of students wanting more education on prudent antibiotic use or general antibiotic use ranged from 20.3% (Sweden) to 94.3% (Slovakia), with a mean of 66.1%, and was strongly inversely correlated with preparedness scores. Higher prevalence rates of antibiotic-nonsusceptible bacteria were associated with lower preparedness scores and higher self-reported needs for further education (p < 0.01).Education is an important and necessary tool in AMS. In a recent study including 7,328 responses from 179 medical schools in 29 countries, Behavioral and social science research is underutilized in the development of antimicrobial prescribing interventions. Although feedback further increased the intervention effect, and although enabling interventions that included feedback were more effective than those that did not (moderate‐certainty evidence), feedback was used in only a minority of enabling interventions.The recent Cochrane review of 221 studies shows that a majority of programs used educational interventions and that behavioral interventions are seldom used.,13 In this setting, behavioral interventions aimed at changing the way clinicians approach suspected infection in the ICU are more likely to have persistent beneficial effects than simpler restrictive measures. For example, the “watchful waiting” strategy initially proposed by Yu et al. and recently reviewed by Denny may be an attractive option in the ICU. Close monitoring of multiple physiological parameters can facilitate the withholding of empirical antibiotics in patients considered to be at low risk of adverse effects if the attending physicians view the reduced exposure to antibiotics as a desirable outcome.In addition, one should remember that the diagnosis of infection in critically ill ICU patients is frequently riddled with difficulties and uncertainty. This can lead to the overdiagnosis of sepsis and unnecessary antibiotic use, which can be associated with worse outcomes.,17 In this scenario, information technology may play an important role, and the use of electronic dashboards as well as nudges should be encouraged.,19Therefore, both educational and behavioral interventions should be included in AMS programs. Qualitative evidence highlights the influence of social norms, attitudes, and beliefs on antimicrobial prescribing behavior. Behavioral interventions, such as decision aids, desired action as the default option, the use of nudges, and pathways designed based on habits and patterns, require the development of systems that address human factors. The lack of this behavioral approach may be a factor contributing to the challenges that beset interventions aiming to influence prescribing behavior and optimize the prescription of antimicrobials.,21 An ideal dashboard should provide information on the actual resistance patterns as well as the dynamics of these patterns, the use of antimicrobials, adherence to processes of care  and healthcare-associated infections. This technology-based element should be coupled with behavioral interventions.The use of near real-time information is feasible through the interoperability of different informatics systems and antibiotic/pathogen dashboards. This approach has a “feedback effect” and may substantially improve knowledge of resistance patterns and better inform the decision to use empirical antibiotics in the ICU. With the increased use of electronic medical records and streaming analytics, dashboards can be made available for ICU physicians with near real-time updates.Despite evidence demonstrating the impact of behavioral determinants and social norms on prescribing, they are often not given adequate consideration in the design and evaluation of interventions. The incorporation and application of behavioral sciences supported by appropriate multidisciplinary collaboration is recommended. Usual behavior must be investigated as a first step to changing it, with recognition of the personal, social and environmental factors affecting behavior. In fact, to influence the antimicrobial prescribing of individual healthcare professionals and eventually change culture, interventions need to address prescribing etiquette and use clinical leadership within existing clinical groups to influence practice. Gabbay et al. showed that clinicians rarely access and use explicit evidence from research or other sources directly but rather mostly rely on “mindlines” - collectively reinforced, internalized and tacit guidelines. They showed that mindlines were mainly informed by their own and their colleagues’ experiences, their interactions with each other and their interactions with opinion leaders, patients and pharmaceutical representatives. They tend to be iteratively negotiated with a variety of key actors, often through a range of informal interactions in fluid “communities of practice”. Pakyz et al., in a qualitative study using semistructured telephone interviews with 15 AMS member pharmacists and six physicians representing 21 unique academic medical centers, demonstrated that successful implementation of AMS strategies was found to be related to communication style, types of relationships formed between the AMS and non-AMS personnel, and conflict management. Success was also influenced by the availability of human and health information technology and the ability to generate and analyze AMS-specific data.As expected, different AMS interventions have different levels of evidence and different likelihoods of efficacy . HoweverMoreover, as it is largely supported in the literature and by national organizations including Public Health England, British Society for Antimicrobial Chemotherapy and major international governments and organizations, AMS requires cross-specialty collaboration and clinical service engagement. The promotion of leadership from within cohorts internally drives behavior change towards antimicrobial use. The AMS topic must be part of the agenda of each clinical service that must engage in the definition of goals and targets and in the intervention design, implementation and monitoring. The hospital AMS unit must understand that leadership is not wielding authority but rather empowering people and that, as in any quality improvement program, the central AMS unit must move from holding power to sharing power and finally to handing power to peripherally intervening units.Therefore, there is no gold standard stewardship model. A national guideline is helpful, but effective implementation must be customized to each of the services intervened. Tailored approaches are required, defining organizational and cultural determinants, to ensure that antimicrobial stewardship is effectively implemented everywhere.In each hospital, AMS should be viewed as a series of customized quality improvement initiatives linked by a common global goal. Quality improvement initiatives should follow a prespecified improvement cycle that includes extensive planning but also measure the results of the implemented actions. As with any quality improvement initiative, AMS needs the following: a customized target and time-to-target definition, including documentation of the specific prescribing behavior that was targeted by the intervention; a change package; a feedback structure that allows the provision of a summary of clinical performance of healthcare over a specified period of time; and action planning, with the identification of quality gaps, room for improvement, rewards or motivations for meeting a target and the use of action plans if the target was not met. Further improvement may be achieved with additional behavior change intervention functions in a series of levered Plan-Do-Study-Act cycles. However, metrics and indicators should be defined locally and should differ by setting, as goals may and should also be diverse.In 2016, a consensus expert panel on metrics assessing the impact of stewardship interventions on a patient level in an acute-care setting was assembled and defined a set of process and outcome indicators ready for immediate use and tracking.Regardless, the implementation and use of a database that provides continuous feedback of metrics and indicators to providers is fundamental but often a real-life problem. In general, surveillance metrics are derived from separate electronic data sources: antibiotic prescription data (pharmacy-based), microbiology results (laboratory-based), diagnostic codes (administration-based) or a combination thereof. Surveillance is not the primary purpose of these sources of information, and using them often results in poor matching of antibiotic prescription data with the corresponding clinical and microbiological information. Their ability to represent the complex nature of the antibiotic treatment decision-making process, and thus their practical usefulness to provide insight into antibiotic prescription, is limited. With the linking of these sources, ideally inside the electronic health record, a deeper understanding of the different factors driving antimicrobial use can be obtained. Interfacing electronic health records, laboratory systems and specialized or general (but customized) analytics tools has become a more common and widely implemented strategy. Antibiotic prescription data were prospectively merged with diagnostic and microbiology data by ICU physicians through dedicated software during a 4-year period. Definite focus of infection and probability of infection (high/moderate/low) were reassessed by dedicated ICU physicians at patient discharge. By prospectively combining antibiotic, microbiology and clinical data, a longitudinal, multifaceted dataset on antibiotic use/infection diagnosis was constructed. Namely, 80% of antibacterial days of therapy were linked with infection, the predominant foci being the respiratory tract (49%), that a microbial cause was identified in 56% of the cases and that moderate/low probability infections accounted for 42% of antibacterial days of therapy for respiratory tract infections. This allowed the identification of antibiotic prescription patterns that require future antibiotic stewardship attention.Recently, De Bus et al. described the system used in the Ghent University Hospital ICU.In our opinion, AMS should always be viewed as a quality improvement initiative, requiring an evidence-based, ideally bundled, change package; a clear definition of locally adapted goals, indicators and targets; a dynamic measurement and data collection system with feedback to prescribers on a continuous basis; a strategy for building capacity ; a plan to identify and approach areas for improvement and address quality gaps using educational and behavioral interventions; and ICU leadership commitment and staff engagement, with accountability and responsibilities. The individual impact of various public campaigns in Europe between 1997 and 2007 has been estimated to be equivalent to a 6.5% to 28.3% drop in the mean level of overall antibiotic use. Factors leading to successful awareness campaigns include the following: targeting a wide audience, such as families, patients, healthcare workers, community pharmacists and policymakers; using mass and social media; repeating simple key messages; and maintaining the diffusion of these messages even after the end of the campaign, thus globally improving health literacy. In fact, sustaining the impact obtained is the main difficulty, but this objective may be achieved by incorporating this concept into the clinician-patient relationship, namely, providing patients and families with information on treatment options, including evidence of effectiveness and likely benefits and risks of harm to support patient engagement and shared decision making. Consumer representation on antimicrobial stewardship committees may also enable effective communication.There is good evidence that public campaigns promoting responsible antibiotic use may be associated with reductions in overall antibiotic use.Antimicrobial stewardship should be performed addressing preservation of the effectiveness of the antibiotic as the main purpose; as a multifaceted intervention, using structural, restrictive and enabling strategies; using both educational and behavioral interventions and information technology-based dashboards; as an intervention driven by the service/intensive care unit intervention, building capacity and progressively handling leadership from the antimicrobial stewardship central unit to the local team; by defining customized, local goals and promoting constant feedback and closing the gap; as a quality improvement initiative; and involving consumers (patients and families) and society as a whole.


SlHAKs) are differentially expressed during fruit development and ripening. The highest-expressed gene was SlHAK10 when fruit reached breaker and ripening. SlHAK3 and SlHAK19 were highly expressed at breaker, and SlHAK18 was highly expressed at ripening. These might be related to the formation of tomato fruit ripening and quality. SlHAK4, SlHAK6, SlHAK8, and SlHAK9 were significantly downregulated with fruit ripening and induced by low K. The expression level of SlHAK6, SlHAK10, SlHAK15, and SlHAK19 were significantly increased by blue SL or red combined blue SL during breaker and ripening. Blue SL or red combined blue SL increased content of phytoene, β-carotene, α-carotene, and γ-carotene and accelerated fruit coloring by enhancing K uptake in roots and transport in fruits during fruit ripening. This was consistent with the expression level of SlHAK6, SlHAK10, SlHAK15, and SlHAK19 during fruit development and ripening. The key genes of photoreceptors, light signaling transcript factors as well as abscisic acid (ABA) transduction induced by blue SL or red combined blue SL were consistent with the upregulated genes of SlHAK6, SlHAK10, SlHAK15, and SlHAK19 under blue SL and red combined blue SL. The K transport in tomato fruits might be mediated by light signaling and ABA signaling transduction. These results provide valuable information for fruit quality control and the light regulating mechanism of K transport and fruit coloring in tomatoes.Supplemental blue/red lighting accelerated fruit coloring and promoted lycopene synthesis in tomato fruits. Potassium (K) is the most enriched cation in tomato fruits, and its fertigation improved tomato yield and fruit color. However, the effects of supplemental lighting on K uptake and transport by tomatoes and whether supplemental lighting accelerates fruit coloring through enhancing K uptake and transport are still unclear. We investigated the effects of supplemental light-emitting diode (LED) lighting  on K uptake in roots and transport in the fruits as well as the fruit coloring of tomatoes (Micro-Tom) grown in an experimental greenhouse in hydroponics. The use of red SL or red combined blue SL enhanced K uptake and K accumulation as well as carotenoid  content in fruits by increasing photosynthesis, plant growth, and fruit weight. The genes related to ethylene signaling were upregulated by red SL. Quantitative real-time PCR (qRT-PCR) results showed that K transporter genes ( Solanum lycopersicum L.) is one of the most important horticultural crops in China and year-round supply is desired by consumers. Fruit color is a key determinant of tomato fruit quality that largely affects the initial quality assessment by the consumer [Tomato  has been used as an efficient light source to meet the demand for high irradiance during plant growth and fruit development and to maintain the productivity of greenhouse tomatoes, particularly during the low irradiance seasons ,3,4,5,6.Potassium (K) is the most enriched cation in tomato , and itsArabidopsis thaliana. However, the regulatory mechanism of light on the absorption and utilization of K has not been reported. Several studies have explored the functional and regulation of K transporters in fruit ripening and coloring such as grape berry [Light was thought to modulate the uptake and utilization of mineral elementals such as nitrogen , phosphope berry , peach [pe berry ,23, and pe berry . Howeverpe berry . 3 supply levels (405 mg/L and 101mg/L) in hydroponic cultivation, respectively. We analyzed K uptake rate, fruit K content, fruit coloring, carotenoid content, and photosynthesis as well as the chlorophyll fluorescence parameters. Moreover, gene expression levels of K transporter, light receptors, and light signaling components were investigated and transcriptome analysis was carried out to provide the molecular mechanism. To understand the role of supplemental red and blue (LED) light on K uptake and transport as well as fruit coloring of tomatoes, ‘Micro-Tom’ tomatoes were treated with supplementary red (660 nm), blue (430 nm), and red and blue (3:1) LED lighting under two KNOAs shown in Pn was significantly increased with red SL or blue SL at normal K supply, and red SL was significantly higher than blue SL, which showed no significant difference at low K supply  family genes in tomatoes as well as the response to low K and supplemental lighting  was used to analyze the transcriptional levels of K transporter KT/HAK/KUP  between RB SL and CK, 68 upregulated and 46 downregulated between B SL and CK, 59 upregulated and 45 downregulated between R SL and CK A. Among PSY1, PSY2, PDS, ZDS, CRITISO, LCYe, ZEP, and VDE were all upregulated by blue or blue combined red SL at the −K level compared with CK , suggesting that this gene may be involved in K transport, and its regulatory mechanism needs further study. The genes related to ethylene transduction (CTR) or receptors (ETR) were induced by red SL or low K treatment compared with CK . The genes related to lycopene metabolism including  with CK B. PSY1, normal K B. The GO with CK C. The ge with CK D. To verperiment .The use of supplemental lighting increased the biomass and yield of tomatoes by increasing the fruit weight and enhancing plant growth . In this−2⋅s−1 of SL reduced the maximum photochemical quantum yield of PSII  indicated the impact of the light on the heat dissipation by leaves [In addition, high intensity blue light might suppress photosynthesis . In thisI Fv/Fm, E, where y leaves . The preConsistent with enhanced plant growth, fruit yield, and photosynthesis, the K uptake rate of tomato roots B was incPn, Gs, and Tr under red SL light  transcription factor RAP2.11 binds to the GCC-box site of the K uptake . In thisSolanum. Lycopersicum L. Micro-Tom) seedlings were cultivated on sponge blocks and fertigated with half strength Enshi formula nutrient solution, as described in our previous research [Tomato (research . The see3)2.4H2O: 475 mg⋅L−1, KNO3: 405 mg⋅L−1, NH4H2PO4: 77 mg⋅L−1, MgSO4.7H2O: 247 mg⋅L−1, EDTA-2NaFe: 10 mg⋅L−1, H3BO3: 1.5 mg⋅L−1, MnSO4.4H2O: 1 mg⋅L−1, ZnSO4.7H2O: 0.11 mg⋅L−1, CuSO4.5H2O: 0.025 mg⋅L−1, and (NH4)6Mo7O24 ·4H2O: 0.01 mg⋅L−1). The KNO3 concentration was reduced to 101 mg·L−1 in the low K supply nutrient solution, in which a reduced amount of KNO3 was replaced by NaNO3. The basal composition of the half strength Enshi formula nutrient solution was a control solution with normal K supply  CK: natural light, without any supplemental light; (2) R: supplemental red light (660 nm); (3) B: supplemental blue light (430 nm); and (4) RB: supplemental red and blue light (red: blue = 3:1). Photosynthetic photon flux density (PPFD) was set at 100 ± 5 µmol⋅mShoot length from the basal part to apical point and taproot length from the basal part to root tip were measured by a ruler 30 days after treatment. Stem diameter below the first true leaf and fruit diameter at 47 DAA (days after anthesis) were measured by a digital caliper. The chlorophyll content was measured by SPAD-502 Plus  30 days after treatment. The fresh weight of shoots (including leaves and stem), roots, and fruits were recorded using an electronic balance 67 days after treatment, and the dry weight was recorded after plants were heated to de-enzyme at 105 °C, then dried at 80 °C until constant. The increase percentage of growth parameters was calculated SL and no SL improvement ratio of supplemental treatment to no supplemental light treatment at the same K level.Tomatoes were harvested at 33, 47, and 61 DAA, then dried in a forced air oven at 80 °C to constant weight, subsequently dry-ashed in a furnace at 550 °C for K content analysis. The content of total K was measured according to the method of flame photometry as described in our previous research .Pn), stomatal conductance (Gs), intercellular CO2 concentration (Ci), and transpiration rate (Tr) of the true leaf below first truss were measured by a Li-6400 photosynthetic system  at 10:00 on sunny days 30 days after treatment. A total of five fully expanded leaves from the five plants of each replicate were randomly selected for measurements.The net photosynthetic rates . The Fv/Fm indicates the maximum efficiency at which light absorbed by PSII is converted to chemical energy, but the NPQ provides an estimate of the heat dissipation by the leaves.Maximum quantum efficiency (Fv/Fm) of PSII and non-photochemical quenching (NPQ) of the whole plant (n = 3) were performed 30 DAT using a PlantExplorer−1⋅week−1) was calculated as described in our previous research [−1) during the fruit development and ripening period was calculated by average of the weekly amount from the first to fourth week and fifth to eighth week, respectively. In the greenhouse, the EC and pH of nutrient solution in each container was measured weekly . The levresearch . Average−1(b*/a*), if a > 0; and 180 + tan−1 (b/a), if a < 0) was used to monitor the pericarp color of tomatoes, where the larger the value, the greener the fruit; conversely, the smaller the value, the redder the fruit. Tomatoes were harvested at 36, 47, and 61 DAA. For each time point, there were three biological replicates consisting of nine fruits. Each fruit was measured on three different points of its pericarp.Pericarp color of tomato fruits was assessed with a spectrophotometer , as described in our previous research . The huev/v/v), and an internal standard was added. After two extractions, the supernatant was evaporated to dryness under a nitrogen gas stream, and reconstituted in a mixed solution of methanol:MTBE. The solution was filtered through a 0.22 μm filter for further liquid chromatography-atmospheric pressure chemical iosziaa-lion-tandem mass spectrometry (LC-APCI-MS/MS) analysis  added to 0.01% BHT and 0.1% formic acid), to solvent B, methyl tert-butyl ether (0.01% BHT). The analysis was carried out at 28 °C with a flow rate of 0.8 mL/min. MS analysis was performed using the API 6500 Q TRAP LC/MS/MS System, equipped with an APCI Turbo Ion-Spray interface, operating in a positive ion mode and controlled by Analyst 1.6.3 software. Carotenoid contents were detected by MetWare . To measure carotenoid composition and concentration, the fruit pericarp of fresh tomato at 47 DAA were collected and stored at −80° until use. The samples were ground into powder. Fifty mg of sample was extracted with a mix of n-hexane:acetone:ethanol . A YMC rch 2021 ) based o−ΔΔCt method [Fruit samples collected at 36, 47, and 61 DAA were rapidly frozen in liquid nitrogen and stored at −80 °C until use. Each treatment sample comprised three biological replicates. Each replicate of nine fruits were collected from at least five different plants. Total RNA was isolated from samples by using the RNAprep Pure Plant Kit , and cDNA was synthesized from 1 μg of total RNA by using the PrimeScript TM RT Reagent Kit with gDNA Eraser  . qRT-PCR was performed using previously described methods [t method . qRT-PCR® Ultra™ RNA Library Prep Kit for Illumina®  following the manufacturer’s recommendations and index codes were added to attribute sequences to each sample. Three biological replicates were performed for RNA transcriptome analyses. The library preparations were sequenced on an Illumina Hiseq 4000 platform by Beijing Allwegene Technology Company Limited  and paired-end 150 bp reads were generated.Fruit samples at 33 DAA in each treatment were collected for RNA-Seq analysis. The pericarp was rapidly frozen in liquid nitrogen and stored at −80 °C until use. Five fruit from different plants in each treatment were pooled for each sample. Total RNA was extracted using the TRIzol method  and used for the production of an RNA-Seq library. Sequencing libraries were generated using the NEBNextp-value < 0.05 found by DESeq were assigned as differentially expressed. GO enrichment analysis of the DEGs was implemented by the GOseq R package based Wallenius non-central hypergeometric distribution [STAR software  was usedribution , which cp ≤ 0.05.Significant differences among the treatments were determined by analysis of variance (ANOVA), followed by Duncan’s multiple range tests of SPSS 22.0 at SlHAK6, SlHAK10, SlHAK15, and SlHAK19 were significantly increased by blue SL or red combined blue SL when fruits reached the breaker stage, which was not observed under red SL. Blue SL or red combined blue SL increased phytoene, β-carotene, α-carotene, and γ-carotene content and accelerated fruit coloring by enhancing K uptake in roots and transport in fruits during fruit ripening, which is consistent with the expression level of SlHAK6, SlHAK10, SlHAK15, and SlHAK19 during fruit development and ripening. The key genes of photoreceptors, light signaling transcript factors as well as ABA transduction induced by blue SL or red combined blue SL were consistent with the upregulated genes of SlHAK6, SlHAK10, SlHAK15, and SlHAK19 under blue and red combined blue SL. The K transport in tomato fruits might be mediated by light signaling and ABA signaling transduction.The use of red SL or red combined blue SL enhanced K uptake in roots and K accumulation as well as carotenoid content in fruits by increasing photosynthesis, plant growth, and fruit weight. The genes related to ethylene transduction or receptors were upregulated by red SL. Increased phytoene and β-carotene content by red SL might be mediated by ethylene signaling transduction. The expression level of


An effective antibiotic stewardship program relies on the measurement of appropriate antibiotic use, on which there is a lack of consensus. We aimed to develop a set of key quality indicators (QIs) for nationwide point surveillance in the Republic of Korea.A systematic literature search of PubMed, EMBASE, and Cochrane Library (publications until 20th November 2019) was conducted. Potential key QIs were retrieved from the search and then evaluated by a multidisciplinary expert panel using a RAND-modified Delphi procedure comprising two online surveys and a face-to-face meeting.The 23 potential key QIs identified from 21 studies were submitted to 25 multidisciplinary expert panels, and 17 key QIs were retained, with a high level of agreement . After adding up the importance score and applicability, six key QIs [6 QIs (Q 1–6) for inpatients and 3  for outpatients] were selected. (1) Prescribe empirical antibiotic therapy according to guideline, (2) change empirical antibiotics to pathogen-directed therapy, (3) obtain culture samples from suspected infection sites, (4) obtain two blood cultures, (5) adapt antibiotic dosage to renal function, and (6) document antibiotic plan. In surgical prophylaxis, the QIs to prescribe antibiotics according to the guideline and initiate antibiotic therapy 1 h before incision were selected.We identified key QIs to measure the appropriateness of antibiotic therapy to identify targets for improvement and to evaluate the effects of antibiotic stewardship intervention. The increased use of broad-spectrum antibiotics is closely related to antimicrobial resistance , 2. TherIn the Republic of Korea (ROK), point surveillance of appropriate antibiotic use was conducted for 20 medical institutions in 2018, and the appropriateness was determined based on expert opinion . This exWe used a four-step RAND-modified Delphi method to develop a set of QIs to measure the appropriateness of antimicrobial use in adult and hospitalized pediatric patients, outpatients, or patients receiving surgical prophylaxis , 11. FigWe performed a systematic search using a protocol designed by two independent medical librarians (D.W.S and M.L). We screened the literature using databases of PubMed, EMBASE, and Cochrane Library for papers published up to 20th November 2019. The search strategy is shown in Additioinal file Data on potential QIs were extracted by four researchers . The QIs were excluded if they were: not concerned with antibiotic use for a specific group of patients, non-normative, or developed for each institution and not for patients. The extracted QIs were then clustered into different non-overlapping logical themes based on the definition of responsible use. When a QI could be allocated to more than one theme, the predominant theme was chosen based on consensus between two authors (B.K. and S.Y.P.). Duplicates were removed, and the QIs were rephrased as a recommendation. The clustering, aggregating, and rephrasing steps were undertaken consensually among four authors .We emailed invitations to different specialists for their participation in 25 expert panels. The panel of doctors comprised experts working at university-affiliated hospitals in the ROK. During panel selection, we aimed to select experts representative and responsible for antibiotic prescriptions. The panel comprised infectious disease specialists n = 13), laboratory medicine doctors (n = 3), pediatric infectious diseases specialists (n = 2), urologists (n = 2), otorhinolaryngologist (n = 1), gastroenterologist (n = 1), pulmonologist (n = 1), general surgeon (n = 1), and researchers of the National Evidence-Based Healthcare Collaborating Agency (n = 1)  to all participating panelists. The panelists were asked to select from the following three answers: ‘agree,’ ‘disagree,’ and ‘cannot assess.’ The rephrased indicators were accepted if at least 70% of the experts agreed with the new formulation. Furthermore, we asked the panelists to consider the importance of potential QIs that could be used as key indicators for antibiotic use in the ROK, with a Likert scale score from 1 ‘less important’ to 5 ‘highest importance’. If the QIs could be evaluated in point surveillance, we considered them applicable. This was finally confirmed by four researchers . We excluded QIs with durations in which appropriateness was difficult to evaluate by point surveillance.The systematic literature search identified 4293 articles, of which only 21 articles were finally selected after screening against the inclusion/exclusion criteria  panelists responded to the first online questionnaire. Among the 23 potential QIs, 13 QIs (57%) were accepted, 6 (26%) were discussed, and 4 (17%) were rejected  panelists participated in this meeting. Among the six potential QIs from the first online questionnaire round discussed, three were conclusively accepted, and three were rejected. QI 10 was merged with QI 1. Among the three suggested QIs from the first survey, one QI  was accepted. The other two QIs  were merged with QI 1 and QI 2, respectively  were included in the second online questionnaire. Twenty-three 92%, 23/25) panelists participated in this survey. All potential QIs were accepted , empiric therapy (QI 1), dosing (QI 7), and definite therapy (QI 6). QIs related to therapy duration were not selected, although it got a considerably high score on the importance scale among experts. Therapy duration is increasingly an important focus area for antimicrobial stewardship activity. However, expected applicability was below 10% based on previous studies , 13, 22.Assessing antibiotic use's appropriateness can be divided mainly into evaluating the entire antibiotic options and evaluating certain antibiotics or diseases . In addiTo date, the most widely used QIs are 11 indicators that were selected by van den Bosch et al.  in the NThe advantage of QIs over expert judgment is that the evaluation results of each QI show the areas that need improvement. In addition, comparisons with other medical institutions show whether the specified institution needs improvement. Another advantage is that the same criteria can be applied every year to determine whether one’s institution has improved. In Australia, four key QIs  and inappropriate antibiotic prescription rates are presented annually along with the target levels . Based oA limitation of this study is that members of the expert panel were only Koreans, and none was with pharmacy expertise. The QIs would be difficult to apply in other countries with different medical environments from the ROK. Pharmacy expertise was suggested as a core element of hospital antibiotic stewardship programs; however, the current antimicrobial stewardship program is mainly performed by infectious diseases specialists in the ROK , 32. SecIn this study, key QIs that can be applied to hospitalized patients, outpatients, and surgical prophylaxis were selected in the ROK. Not only will these key QIs be applied in national point surveillance initiatives in the ROK in 2020, but also other users will be able to use the QIs for antibiotic stewardship programs or in educational materials for appropriate antibiotic use. Evaluators will be able to prioritize antibiotic use based on the important indicators identified in this study. It is expected that the application of key QIs will complement and apply the advantages and limitations of the evaluation indicators experienced by the actual evaluators and researchers.Additional file 1. Figure: Search strategy for the literature review.Additional file 2. Table 1: Final list of 21 articles selected after a systematic literature search.Additional file 3. Table 2: Title and affiliations of expert panels.