Large amounts of waste glass are generated along with the manufacturing of glass products, causing detrimental effects on the environment. Through crushing and ball-milling, waste glass powder (WGP) can be acquired from glass bottles and has been suggested in cementitious systems due to its potential pozzolanic activity. To better understand the impact of WGP on cementitious composites, experimental tests of rheology, heat of hydration, and strength development were conducted on cement pastes with and without WGP. Results show that the rheological performance of cement paste is improved when WGP with particles passing through 80 μm sieves is incorporated. The retarding effect and pozzolanic reaction were observed through X-ray diffraction patterns and thermo-gravimetric parameter analyses. A calcium hydroxide (CH) content calculation further confirms the secondary reactivity of WGP in cement pastes. Compared with the samples without WGP, the normalized CH content of binder per unit mass containing 35% WGP decreased by 21.01%, 24.94%, and 27.41% at the ages of 1, 28, and 90 days, respectively, which contributes to late-age strength development of pastes. At the same time, the hydration per unit of cement was increased by 21.53%, 15.48%, and 11.68%, which improved the cement efficiency. In addition, WGP particles provide nuclei for hydration products, facilitating the subsequent growth of C-S-H and strength development in late ages. Based on value engineering analysis, WGP was found to reduce the impact of Portland cement on the environment by 34.9% in terms of carbon dioxide emissions, indicating a bright prospect for WGP in the cement industry. Glass materials are widely used in daily life and industrial applications due to their stable chemical properties and aesthetic appearance. Large amounts of waste glass are generated along with the manufacturing and application of various glass products, such as waste glass bottles. The annual production of waste glass is about 21.23 million tons in China, whereas the recycling rate is merely 30.4%, causing occupation of land resources and pollution of adjacent environments due to its unbiodegradable nature [2, accounting for 70% or more [2) emissions. For instance, in 2020, cement clinker production reached 1.579 billion tons on the Chinese mainland alone, and the emissions of CO2 accompanying it reached over 1.23 billion tons, taking up 12.43% of the total CO2 emissions in all industries. Aiming at mitigating the increasingly tense greenhouse effect, specific schemes for the strategy of carbon neutrality and peak emissions have been deployed, advocating new patterns for high-quality/sustainable cement development. The most effective way is to reduce the amount of silicate cement clinker by incorporating a high volume of supplementary cementitious materials (SCMs) [The main components of waste glass are generally acknowledged as amorphous SiO or more ,2. This s (SCMs) , and higs (SCMs) ,9. Utilis (SCMs) ,11,12,13A decrease in the particle size of WGP was reported to significantly increase the pozzolanic activity ; 75 μm w2 emissions, was quantified correspondingly.Thus, recycling waste glass bottles into WGP to produce a greener cementitious composite seems practicable. However, the effect of WGP from local waste glass bottles on the hydration and microstructure of cement paste has not been fully understood, especially for WGP with similar particle sizes to cement. Whether the rheological and mechanical properties of pastes containing different amounts of local WGP could meet relevant standards will be critically investigated for further application. Therefore, it is necessary and of great significance to study the effects of recycled WGP from waste glass bottles on the fresh and hardened properties of cementitious composites. Experimental tests of WGP content on the performance variation of cement pastes were carried out accordingly. Mineral compositions from an X-ray diffractometer (XRD) and microstructure morphologies under scanning electronic microscopy (SEM) were obtained to analyze the impact of WGP in substitution with cement. The ecological effect, focusing on CO3 and 2.51 g/cm3, respectively.Common white-type waste glass bottles were provided by a local waste collection station in Guangzhou, China. Those bottles were first cleaned and dried, then crushed and ground in a ball mill to powder, as schematically shown in 2 (64.90 wt.%), CaO (19.62 wt.%), and Na2O (10.06 wt.%), implying a typical soda-lime silica glass and an alkaline glass material. Such a high content of SiO2 (mostly amorphous silica) would reveal pozzolanic activity based on previous research and related standards [The chemical compositions of both materials are listed in tandards ,26,27. FDifferent substitution ratios of WGP for cement are proposed by British standard BS EN 196-1 , interna3 were prepared for compressive strength evaluation at the ages of 7, 28, and 90 days. All specimens were demolded after film covering for 24 h, then moved to a standard curing chamber at 20 ± 2 °C and ≥98% relative humidity until the test ages. After the compression tests were conducted at an MTS hydraulic universal testing machine, samples were carefully prepared from the core of the cubes for further microstructural analysis.To better illustrate the effect of local WGP on the properties of cement paste, the above weight percentages of 20%, 25%, and 30% were selected. In addition, 15 wt.% and 35 wt.% WGP replacements for cement were designed as contrasts. Detailed mix proportions with a constant water-to-cement ratio of 0.4 are listed in A rheometer with a co-axial cylindrical rheometer was applied to investigate the rheological parameters of all pastes. The shear speed was first increased from 5 to 100 revolutions per minute (RPM) in a step of 5 RPM, maintained for 15 s till the peak. Then, the shear speed was decreased at the same interval . The BinThe heat evolution of all mixtures was obtained via the TAM air isothermal calorimeter. According to the equilibrium principle of specific heat capacity, Equation (1) was proposed to calculate the amount of cement and free water at a constant quartz sand quantity .Thermo-gravimetric and differential thermal analysis (TG-DTA) experiments were carried out on the NETZSCH STA 2500. The temperature range was 30 °C to 1000 °C at a rate of 10 °C/min under a dynamic NThe micromorphologies of hydration products were photographed by an SNE-4500 M Plus electron microscope. The instrument voltage was 15 kV, and thin layers of gold were sprayed on the surface of paste samples in advance to guarantee good conductivity for concrete specimens.Shear stress-rate curves of fresh cement pastes with 15 wt.% WGP and 30 wt.% WGP are displayed in Heat evolution in the first 168 h of plain paste, 15 wt.%, and 30 wt.% WGP-modified pastes is plotted in 3S)/dicalcium silicate (C2S) dissolution and CH formation [2O in WGP serves as a catalyst for early C-S-H formation and development [When heat evolution rate per unit cement is discussed b, higherormation . Along wormation  suggesteelopment . In addielopment .The cubic compressive strengths of all mixtures after standard curing for 7, 28, and 90 days are summarized in As for the activity index of WGP, mainly three standards are quoted and compared. According to ASTM C311 , a 20% W3), dicalcium silicate (C2S), tricalcium silicate (C3S), quartz (SiO2), ettringite (3CaO·Al2O3·3CaSO4·32H2O), and other minerals. The quartz SiO2 with diffraction peaks at an age of one day may be the impurity fraction contained in the cement itself. The hydration processes of C3S and C2S can be expressed in Equations (2) and (3), in which the hydration of C2S is a bit slower and gives off less heat under the same conditions [XRD patterns of samples from plain pastes and 35 wt.% WGP-modified pastes at ages of 1, 7, 28, and 90 days are plotted in nditions .(2)2C3S3S2H3, suitable for stoichiometric calculations [Herein, hyphens in C-S-H are used to represent the category of calcium silicate hydrated since the chemical composition of C-S-H is not constant and changes with hydration degree and original minerals. When hydration is completely accomplished, C-S-H can then be described as Culations . Activat2S and C3S gradually decrease as the hydration process proceeds, while the intensity of the hydration product CH slightly increases. When recycled WGP is adopted, the hydration degree of cement becomes higher, as depicted in 2S and C3S are even greater in comparison with the control group, indicating an accelerating effect of WGP. Meanwhile, CH diffraction peaks exhibit a weakening trend in pastes with WGP. Herein, at one day, the difference between CH peaks of paste with and without WGP is not obvious. However, after 90 days of curing, CH peaks in WGP-modified paste are much smaller than those in the control group, implying consumption of CH in the presence of WGP. As cement hydration proceeds, CH content increases and the concentration of hydroxyl ions increases, prompting the pozzolanic reaction of WGP with amorphous silica [s silica . Once co3. Therefore, in order to minimize the effect of CaCO3, a modified calculation method is proposed. The measured CaCO3 content usually includes both raw material and CH carbonation, so it is essential to determine the CH and CaCO3 content of the raw cement. CaCO3 content measured typically includes both raw material and CH carbonation, which makes the determination of CH and CaCO3 in the original cement critically necessary. The TG and DTG curves of cement, plain paste, and 35 wt.% WGP-modified paste are displayed in 3. Based on the data from TG-DTG tests, the amount of CH can be quantitatively calculated as follows: The results are summarized in The pozzolanic activity of WGP could be reflected more specifically by the CH content change in pastes. Thermo-gravimetric parameters enable identification of physical phases and determination of CH content in hydrated pastes ,50. BaseFirstly, for cement, the weight loss around 400 °C caused by CH dehydration is 3 decomposition is 3 exists in raw cement.The weight loss around 650 °C caused by CaCO3 is 3, the original amount of CaCO3 is Secondly, Thirdly, chemical-bonded water can be calculated right after decomposition of CH  as 100%−Micromorphologies of pastes containing WGP from waste glass bottles are shown in 2 emissions, accounting for nearly a quarter of total CO2 emissions [V) from the perspective of economics is adopted to analyze WGP impact by comparing the performance function (F) and carbon cost (C) of cement paste, expressed in Equation (7) [The cement manufacturing process contributes greatly to COmissions . WGP to tion (7) .(7)V=FC2 emissions in the production of 1 ton of cement include those from raw material extraction, manufacturing, and transport (35.15 kg), decomposition (462.87 kg), calcination (505.92 kg), and product transportation (58.56 kg) [2. For WGP recycled from local waste glass bottles by crushing, grinding, and sieving, the main equipment used for the recycling process is ball mills and sieving machines. The consumption of electricity is recorded as 3 kW·h per ton of WGP. When coal-fired power is assumed, CO2 production is 0.93 kg/(kW·h), which gives a CO2 emission of 2.79 kg, according to Cabrera and Wolley [This study focuses on the function of 90-day compressive strength and the carbon cost during the whole process of pastes with and without WGP. Generally, CO8.56 kg) . To sum 3 of paste, and the emission of CO2 reaches 1452.44 kg. When the cement is partially substituted by WGP from glass bottles, the cost greatly decreases based on the above analysis of CO2 emissions. CO2 emissions are taken as the C, i.e., the cost of carbon. In this paper, the compressive strength function is taken as F. For instance, 35 wt.% WGP-modified paste costs 945.42 kg, merely 65.1% of the plain paste, reducing it by 34.9%. And the value (The cost and function of plain paste and pastes with 15%, 20%, 25%, 30%, and 35% WGP in weight are listed in Recycling waste glass bottles into cement paste is technically feasible in terms of the mechanical properties required by relevant standards.2 emission analysis via value engineering analysis.WGP reduces the ecological impact of Portland cement by 34.9%, according to COThe addition of 35% WGP increased cement hydration by 21.53%, 15.48%, and 11.68% at curing ages of 1, 28, and 90 days, respectively, compared to without WGP.The pozzolanic reaction of WGP consumes CH in cementitious systems, as confirmed by XRD patterns and CH content analysis from TG-DTG curves. Compared with the samples without WGP, the normalized CH content per unit binder mass containing 35% WGP decreased by 21.01%, 24.94%, and 27.41% at the ages of 1, 28, and 90 days, respectively.WGP particles provide nucleation places for hydration products, facilitating subsequent growth of C-S-H and strength growth in late ages.In the present study, WGP recycled from local waste glass bottles is introduced in cement paste production. Its impact on the performance and carbon dioxide emissions of cement pastes were investigated. Based on experimental tests of rheology, heat of hydration, strength, and discussions of XRD, TG-DTG, and microstructure results, the following conclusions can be drawn:


In the construction process of an asphalt concrete impermeable core wall, the interlayer bonding of the core wall is the weak link of the core wall structure and also the focus of construction, so it is important to carry out research on the influence of interlayer bonding temperature on the bending performance of an asphalt concrete core wall. In this paper, we study whether asphalt concrete core walls could be treated with cold-bonding by fabricating small beam bending specimens with different interlayer bond temperatures and conducting bending tests on them at 2 °C. The effect of temperature variation on the bending performance of the bond surface under the asphalt concrete core wall is studied through experimental data analysis. The test results show that the maximum value of porosity of bituminous concrete specimens is 2.10% at lower bond surface temperature of −25 °C, which does not meet the specification requirement of less than 2%. The bending stress, strain, and deflection of bituminous concrete core wall increase with the increase of bond surface temperature, especially when the bond surface temperature is less than −10 °C. If the lower bonding surface temperature is less than 10 °C, the upper layer of asphalt mixture with large grain size aggregate cannot be effectively buried in the low bond surface, resulting in flat fracture and brittle damage to the specimen, which is detrimental to construction quality; therefore, the bonding surface should be heated so that the temperature of the bottom bonding surface is 30 °C. If the lower bonding surface temperature is 10 °C or above, no heating is required. Hydraulic asphalt concrete core walls, panels, and geomembranes are the main impermeable structures for pumped storage power plants ,2,3, amoThe surface temperature of the hydraulic asphalt concrete core wall bond is mostly inconsistent within each country, and some of the German asphalt roll concrete dams, when paved, require the subgrade surface temperature to be in excess of 25 °C; if this is not the case, heating of the subgrade surface is required . In 1989Researchers are currently studying the interlayer bonding performance of asphalt concrete core walls at a variety of temperatures. Cai Qian , for exaTemperature regulation is a major challenge in the construction of hydraulic asphalt concrete fields. The majority of the aforementioned researchers’ studies on the bonding surface of an asphalt concrete core wall are performed at room temperature, although it is unclear whether cold, low-temperature binding meets the quality criteria.Small beam bending specimens were prepared in this study by designing different bond-surface temperatures, by controlling the temperature of the binding surface (−25 °C to 70 °C), and by performing bending tests at 2 °C. The primary problem addressed in this study is verifying that the binding surface can be treated with cold binding, which may provide a benchmark for later construction and maintenance of asphalt concrete core walls in colder regions. It is therefore important to perform investigations into the effect of interlayer bond temperature on the flexural performance of asphalt concrete core walls.The trabecular bending specimens were prepared by designing different joint surface temperatures and the bending test was carried out at 2 °C. The flexural strength of asphalt concrete and the strain corresponding to flexural strength and deflection across the middle span are obtained. Finally, stress strain analysis, fracture section analysis, and data comparison analysis are carried out according to the experimental results.The asphalt model used in this test is Karamay 70 asphalt. The coarse aggregates were limestone aggregates, divided into three categories, according to 9.5–16, 4.75–9.5, and 2.36–4.75 mm; the fine aggregate was limestone artificial sand, 0.075–2.36 mm, and the filling was limestone mineral powder, up to 0.075 mm, ground by a laboratory ball mill .The raw material testing was based on SL 501-2010 “Design code of asphalt concrete facings and cores for embankment dams” . The per(1)Coarse aggregatesCrude aggregate has a particle size of 19~2.36 mm and acts mainly as a skeleton in asphalt concrete, the quality of which is an important index of asphalt concrete strength. In this paper, limestone was used as coarse aggregate, which was divided into 5 particle size classes by broken sieve. The surface density, water absorption, adhesion to asphalt, crushing rate, and durability of the two coarse aggregates were tested and compared. The results of mass tests of the coarse aggregate are shown in (2)Fine aggregatesFine aggregate particle size falls within 2.36–0.075 mm, and its main role is to lubricate the asphalt concrete, in order to provide fluidity for the asphalt concrete, so that the asphalt concrete at a certain temperature can better form the flow dynamic, be easy to pave, and have good compaction. The fine aggregate also fills the larger gaps between the coarse aggregate, making the aggregate more dense. In this paper, fine aggregate was prepared from hard limestone, and its surface density, water absorption, water stability grade, durability, and mud content were tested and compared. The results of quality inspection of fine aggregate are shown in (3)FillerThe role of filler is to fill the fine voids between coarse and fine aggregates to make the asphalt concrete aggregate more dense, which helps to better improve the impermeability properties of asphalt concrete. The filler comprises ground limestone as the raw material, and the main test indexes are surface density, water content, hydrophilic coefficient, and so on. The quality test results of the fillers are shown in (4)AsphaltAsphalt is the core material of the asphalt concrete impermeable layer, and the quality of asphalt is related to its impermeable performance. At present, the comprehensive performance of asphalt concrete is mainly judged by three indexes: needle penetration, softening point, and ductility. Therefore, in this paper, the three major indicators of the selected asphalt (before film oven and after film oven) were tested. The asphalt quality test results are shown in The test results in The design grading of mineral for hydraulic asphalt concrete is calculated using the improved Ding Purong formula based on Fuller’s (Fuller) formula.iP is the passing rate of aggregate at id, %; id is the particle size of a grade, mm; P0.075 is the passing rate of aggregate when the sieve is 0.075 mm, %; maxD is the maximum particle size of aggregate, mm; and r is the grading index.In the Formula (1): The mineral grading index is 0.38, the oil to stone ratio is 7.2%, and the filler amount is 12%. The aggregate grading curve is shown in The mineral aggregate gradation index refers to the proportion of mineral aggregate that constitutes each particle size of asphalt mixture. The oil-to-stone ratio means the weight percentage of the amount of asphalt and minerals in the asphalt mixture. The amount of filler refers to the amount of mineral powder used in the asphalt mixture to fill the voids of asphalt concrete in the overall mineral content.The test equipment mainly include the following: bending test machine ; motor controller (500 W); data collector (N); computer; pressure sensor ; thermometer (−30 °C~70 °C ); cold box (−35 °C~24 °C ); glass water; and flame spray lamp.The bending test uses the motor controller to control the motor at the bottom of the bending test instrument, drives the thermostatic waters support in the specimen to move upwards, and fixes the pressurized rod position, so that the support forms a three-point bending test on the asphalt concrete beam. The force applied to the middle of the specimen is transmitted from the rod to the upper pressure sensor and then transmitted to the data collector by the pressure sensor; the bending deformation in the middle of the specimen is transmitted to the data collector by the displacement sensor and finally stored in the computer in the form of electrical signals in the computer’s asphalt concrete bending test system.(1)Aggregates of a certain ratio are heated in a high-temperature oven for 3 to 4 h at 170 °C;(2)The aggregate and bitumen in proportion to the bituminous concrete mixer are heated, stirring at 160 °C for 90 s to form an asphalt mixture;(3)In a mold used for the production of specimens sized 300 × 150 mm, samples are divided into four layers of 75 mm each in order to simulate the mass of interlayer adhesion under different test conditions. The lower layer of asphalt concrete is prepared, and compaction is performed 7 times each round, with a total of 15 rounds;(4)The temperature change rate is controlled to about 28.6% of the lower temperature limit of 70 °C specified in the construction specification  for low-(5)The mold is removed after the test block has cooled ;(6)The specimen is then cut into a small, curved specimen size of 250 mm × 35 mm × 40 mm, deviation ±1 mm, ±1 mm, ±2 mm, respectively, with a special cutter. The combined surface located at 125 mm along the length of the cut specimen is well marked.The sample size for the trabecular bending test is a rectangular specimen of 250 mm × 35 mm × 40 mm as required by specification , which i(1)The first step requires the sample to be treated at constant temperature, adjusting the thermostat according to the temperature required for the test. When the thermostat reaches the minimum underwater temperature of  2 °C in (2)The next step is to adjust the test machine. Place and adjust the test machine test piece support, with support distance of 200 mm, and ensure that the upper force rod lower indenter and the support are parallel and centered. Then, turn the motor until the indenter and support are in a horizontal direction and form a certain distance, in order to facilitate the placement of test pieces;(3)Next is to adjust the test specimen thermostat, the thermostatic water tank on the curved test stand, and the temperature of the glass water (specification: −40 °C) as required by the test. Measure the temperature of the water by thermometer and adjust the temperature in real time so that the temperature of the water is within ±1 °C of the test requirement;(4)The constant temperature and temperature-adjusted specimens are placed in the test machine at a height of 35 mm and width of 40 mm, provided that the temperature of the bath meets the test requirements ;(5)The motor controller is adjusted so that the motor rotates at a certain speed with a strain rate of 1%/min, i.e., a span deformation rate of 1.67 mm/min. The load is applied between the specimens and data are automatically collected by computer.(1)When the lower layer of asphalt is applied with the bonding layer temperature of −25 °C and −10 °C, a large band gap appears at the binding surface and can obviously be seen to delaminate, denoting that the binding quality is poor.(2)When the lower asphalt mixture layer is applied with the 10 °C and 30 °C surface temperature setting, small voids appear on the surface and there is no clear delamination, thus denoting good quality.(3)When the lower asphalt mixture layer is applied with the surface temperature setting at both 50 °C and 70 °C, there is no visible delamination and there are no voids in the combined surface, thus denoting good quality.According to DL/T 5362-2018, the tensile strength of asphalt concrete is calculated by Equation (2), and the maximum bending tensile strain is calculated by Equation (3). The stress–strain curves of asphalt concrete at different temperatures are produced separately from the experimental data.bR—flexural strength of asphalt concrete, Mpa; b—width of the span-interrupted specimen, mm; h—height of the span-interrupted specimen, mm; L—span diameter of the specimen, mm; bP—specimen damage at the maximum load, N; bε—maximum bending tensile strain of asphalt concrete, %; and f—the deflection of the span midpoint when the specimen is damaged, mm.In the formula: After the density and porosity of the sample are measured, three specimens are prepared according to the above test procedure at different bonding surface temperatures and the mean of the test results is used as the test result. When the difference between the maximum or minimum of three specimens and the mean of the test value exceeds 15%, the mean value shall be the average. When the maximum and minimum values of the three test samples differ by more than 15% from the median values, the test should be repeated. The relationship between the heating temperatures and the bending strength and tensile strength of the bonding surface at different heating temperatures is compared and analyzed. The experimental results are shown in Density: The density of a material is the mass per unit volume of the material in an absolutely dense state.Porosity: It is the percentage of pore volume in the block material to the total volume of the material in its natural state.P—material porosity, %; V0—material volume in the natural state, or apparent volume, cm3; ρ0—material bulk density, g/cm3; V—absolute dense volume of material, cm3; and ρ—material density, cm3.In the formula: As can be seen from The maximum porosity of bituminous concrete specimens is 2.10% when the temperature of the lower bond surface is −25 °C, which does not meet the requirement of <2% in the design specification for hydraulic bituminous concrete. This is because −25 °C is below the asphalt brittle point, the upper layer of hot material poured into the temperature dissipates faster, and large particles of aggregate in the compaction molding are difficult to embed in the lower layer of material, so the density of the test piece in the compaction molding is difficult to achieve.When the initial loading temperature of the lower bond surface is −25 °C and −10 °C, the force of the specimen is unstable, and force interruption and loading deflections are likely to occur. This phenomenon is due to poor adhesion between the upper and lower layers of the specimen and gaps in the bond surface, as shown in As can be seen from In order to better analyze the effect of interlayer heating temperature on the bending performance, by using 70 °C as the study ontology, the stress ratio, strain ratio, and deflection ratio variation curves were constructed, and the effect of the interlayer heating temperature on the bending performance of asphalt concrete is shown in Stress ratio is the ratio of stress measured at different temperatures to stress measured on bonding surface; strain ratio is the ratio of strain measured at different temperatures to strain measured on the bonding surface; and deflection ratio is the ratio of deflection measured at different temperatures to the deflection measured on the bonding surface.As can be seen from (1)There is a lower bond surface temperature of −25 °C and maximum porosity of 2.10% in bituminous concrete specimens, which does not meet the specification requirement of less than 2%. The bending resistance of asphalt concrete samples met the specification requirements at −10 °C, 10 °C, 30 °C, 50 °C, and 70 °C at lower bonding temperatures but was stable at lower bonding temperatures of 10 °C, 30 °C, 50 °C, and 70 °C. The results show that the critical temperature of the interlayer bond is −10 °C when the temperature of the lower the interlayer bond surface is −10 °C.(2)The bending stress, strain, and deflection of bituminous concrete core wall increase with the increase of the bond surface temperature, especially when the bond surface temperature is less than −10 °C. Through the specimen after fracture cross-section, it can be seen that, when the asphalt concrete lower bond surface is at 10 °C or below, the specimen has brittle damage, and the upper layer of the asphalt mixture with large-diameter aggregates can not be effectively embedded in the lower layer of the mixture, thus resulting in a more flat bond fracture cross-section.(3)According to the test analysis, the temperature of the combined surface of the lower layer of asphalt concrete is less than 10 °C, which does not guarantee the bonding mass between layers, and should be heated to 30 °C and not to 70 °C as required by the specification. If the temperature of the lower bond surface is above 10 °C, no heating measures are needed, which provides a theoretical basis for the construction of an asphalt concrete core wall under low temperature.In this paper, bending tests were conducted on asphalt concrete specimens in a 2 °C temperature environment, and the bending properties of −25 °C, −10 °C, 10 °C, 30 °C, 50 °C, and 70 °C interlayer bonding temperatures were analyzed. The results are concluded as follows:


When using a rational amount of superplasticizer and fiber, the compressive strength of concrete, even with a minimum cement amount of 350 kg/m3, was at least 65 MPa, its flexural strength was at least 6 MPa, its frost resistance was F200, and its abrasion capacity was not more than 0.30 g/cm2. Concrete with such properties can be used for roadways of any type. Low abrasion capacity and high frost resistance provide the necessary durability of concrete for rigid pavement during operation.The complex effect of the amount of cement, polypropylene fiber , and polycarboxylate superplasticizer on concrete properties for rigid pavement was determined using the methods of experiment planning and experimental–statistical modeling. The fluidity of all the mixtures was S1. The W/C of the mixtures depended on the composition of the concrete and variable from 0.32 to 0.46. It was found that, by increasing the amount of superplasticizer from 1% to 1.8–2%, the compressive strength of concrete increased by 4.5–6 MPa after 3 days and by 7–9 MPa after 28 days. The flexural strength in this case increased by 0.6–0.9 MPa. The use of polypropylene fiber in the amount of 1.5–1.8 kg/m Cement concrete rigid pavements have a number of advantages over bituminous concrete surfaces, which constitute a significant part of highways. Durability and rut resistance are the most important advantages. Recently, rigid pavement has been increasingly used in different countries due to its improved properties with a similar construction cost ,2.Road surfaces are maintained while considering the variable directions of the load from transport and, at the same time, the dynamic effects of the load ,4. Fiber3 steel fibers.Steel fiber is a very effective material for dispersed reinforcement in rigid concrete pavements. In a previous study by Latifa , due to Steel fiber also reduces the shrinkage of concrete pavement during hardening, which is important for road pavements .However, the use of steel fiber significantly increases the cost of concrete ,13. Stee3 of steel fiber or 10.0 kg/m3 of polypropylene fiber led to a reduction in the pavement thickness from 6% to 39% depending on the design method. In another study [3 or steel fiber in the amount of 25 kg/m3.Research shows that polypropylene fiber is almost as effective in concrete pavements as steel fiber. For example, in one study , the useer study , the strPolypropylene fiber increases the concrete durability of hard surfaces by increasing the frost resistance and wear resistance of concrete ,16. For 3 polyvinyl alcohol fiber 20 mm in length, with a diameter of 30 μm, reduced the shrinkage and increased the wear and crack resistance of concrete.Polypropylene dispersed reinforcement reduces the width of the crack opening in road pavements , changesIn the research conducted by Nobili et al. , it was Many studies show that the efficiency of dispersed reinforcement is significantly affected by the length and diameter of polypropylene fiber ,16,23. AChanging the amount of fiber has a mixed effect on concrete properties. In most cases, increasing the amount of fiber to a certain value improves the mechanical properties of concrete, and any further increase in the degree of dispersed reinforcement is no longer effective and reduces the mechanical properties of concrete ,22,23,25Accordingly, the purpose of this study was to determine the complex effect of polypropylene fiber and superplasticizer on the concrete properties of rigid pavements. Such an effect was studied for concrete types with different amounts of cement, considering the possible options that meet pavement strength requirements depending on the road category.Experimental planning methods were used in this research, which allowed for an investigation of the influence of the amount of cement, fiber, and superplasticizer as well as their interrelation . The disThe prerequisite data for the development of fiber-reinforced concrete for rigid pavements with polypropylene fiber of a certain size were previously obtained by the authors of this study . At the The development of fiber-reinforced concrete compositions for rigid pavement using local cement, aggregates, additives, and fiber is important for Ukraine, considering the significant amount of work that needs to be done to rebuild the infrastructure destroyed during the war.-Portland cement CEM II/A-M(S-L) 42.5 R, manufactured by CRH Ukraine  in accordance with ,28;-Crushed stone fraction 5–20 mm in accordance with ,30. Pass-Washed quartz sand with a fineness modulus of 2.59 in accordance with ,31;-Polycarboxylate superplasticizer STACHEMENT 2570/5/G, manufactured by LLC “Stachema Lviv-service”  ;-Polypropylene fiber “X Mesh” was 39 mm long and 0.45 mm with an equivalent diameter, manufactured by LLC “DIIF”   Figure . The ultFor concrete and fiber concrete mixing, the following materials were used:-1, the cement content, from 350 to 450 kg/m3;X-2, the polypropylene fiber content, from 0 to 3 kg/m3;X-3, the superplasticizer amount, from 1% to 2% of the cement weight.XThe investigations of the properties of concrete and fiber-reinforced concrete were carried out according to the optimal 15-point 3-factor plan ,34. The 1) significantly affects all of the properties of concrete. However, for economic and environmental reasons, it is desirable to achieve the properties required for rigid pavement while minimizing cement consumption. The effectiveness of dispersed reinforcement (X2) may vary depending on the strength of the cement–sand matrix. By varying the X2 factor, it also becomes possible to compare the properties of unreinforced concrete and dispersed-reinforced concrete. For the compositions with different amounts of cement and fiber, the reasonable amount of superplasticizer (X3) may vary. The ranges of variation in these factors were selected based on the results of preliminary experiments and taking into account the recommendations of fiber and superplasticizer manufacturers. All three factors varied independently of each other.These factors were chosen for the following reasons: It is known that the cement amount , and 6 prisms 10 × 10 × 40 cm  were manufactured.The hardening of the samples occurred under normal conditions at a temperature of 18–20 °C and a relative humidity of 90–100%.According to ES model (1) and the following ES models confirm the influence of the variable factors on concrete properties with sufficient accuracy only within the factor space of the described experimental study. However, the trends of the composition influence revealed in these studies can also apply to other types of concrete and fiber-reinforced concrete of a similar purpose.The diagram of ES model (1) was plotted in the form of a cube , as show1. The W/C of the mixture is also reduced by 10–12% when increasing the amount of superplasticizer from 1% to 2% of the cement weight, that is, by increasing the level of factor x3. With the introduction of polypropylene fiber in an amount of up to 1.5 kg/m3 (factor level x2 ≈ 0), the W/C of the mixture does not almost change. So, the use of such an amount of fiber does not require an additional introduction of water to maintain equal consistency in the mixture. However, by increasing the amount of fiber to 2.5–3 kg/m3 (close to the maximum level of factor x2), the W/C of the mixture increases by 5–6%, which is equivalent to an increase in the amount of water in the concrete composition by 8–10 L/m3. Thus, the structure and properties of concrete and fiber-reinforced concrete mixtures were influenced not only by the variable factors but also by the change in the W/C of the mixture caused by their variation [The analysis of the diagram in ariation ,40. Thisariation ,41,42.At all 15 experimental points, the compressive strength after 3 and 28 days, the flexural strength after 3 and 28 days, and the abrasion and frost resistance of concrete were determined. The levels of these physical and mechanical properties of the tested concrete and fiber-reinforced concrete mixtures are shown in cm.3) and at the design age of 28 days (fcm) were established as follows:According to The experimental error in the calculation of ES model (2) was 2.063 MPa, whereas the error in the calculation of ES model (3) was 1.644 MPa.For the convenience of analysis, according to ES models (2) and (3), the diagrams in the form of cubes were plotted, as shown in 1), their strength predictably increased. At the same time, increasing the cement amount from 350 to 400 kg/m3 caused a more appreciable strength increase than an increase from 400 to 450 kg/m3. By reducing the W/C of the mixture with equal consistency while increasing the superplasticizer amount from 1% to 2% of the cement weight (factor x3), the compressive strength of concrete and fiber-reinforced concrete increased by 4.5–6 MPa after 3 days and by 7–9 MPa after 28 days. At the same time, in the range of variable amounts of superplasticizer from 1.6% to 2%, the strength of concrete was close to the maximum and changed insignificantly. So, using STACHEMENT 2570/5/G in the amount of nearly 1.8% can be considered reasonable for this type of concrete.From the diagrams and data in 2) in the amount of 1.5–2.0 kg/m3, the compressive strength of concrete increased by an average of 3 MPa both at the early age and design age. Increasing the fiber content to over 2.0 kg/m3 was not effective and reduced the strength of concrete. This is explained by the effect of dispersed reinforcement on the W/C of the mixture with equal consistency. As indicated above, the introduction of the fiber in the amount of 2.0–3.0 kg/m3 caused an appreciable increase in W/C.With the introduction of polypropylene fiber  and 28 days (fc.tf.3). The experimental error in the calculation of ES model (4) was 0.239 MPa, and the error in the calculation of ES model (5) was 0.145 MPa. The diagrams constructed using ES models (4) and (5) are shown in According to 1). At the same time, at an early age, this effect was more noticeable than at the design age. By increasing the amount of cement from 350 to 450 кг/м3 after 3 days, the flexural strength of concrete increased by an average of 1.4 MPa, and after 28 days, it increased by 0.5 MPa. This can be explained by a shift in the strength effect of the cement–sand matrix on the resistance of the concrete structure to tensile stresses. At the initial stage of concrete hardening, the strength of this matrix has a greater influence, but as the age of concrete increases, the influence of matrix adhesion to coarse aggregate becomes more noticeable [It is seen from the diagrams shown in ticeable .3), providing the lowest W/C and, accordingly, the highest compressive strength. Due to the use of dispersed reinforcement, the flexural strength of the tested concrete mixtures increased by 0.5–0.6 MPa. After 3 days, greater efficiency was achieved when using the maximum amount of polypropylene fiber, at the design age, i.e., when using fiber in the amount of 1.6–1.8 kg/m3. Thus, for this factor (х2), the reasonable range is similar to the range that provided the greatest compressive strength. Such an effect of the change in the fiber content on fc.tf can be explained by the necessary change in the W/C of the mixture when dispersed reinforcement is introduced, as described above.At both the early age and design age, concrete mixtures with the amount of superplasticizer 1.7–1.9% by the weight of cement had the highest flexural strength, which coincided with the range of the additive quantity :The abrasion resistance of the tested concrete and fiber-reinforced concrete mixtures was determined on an abrasive wheel using a standard abrasive powder . Based oThe diagram of ES model (6) was plotted, as shown in 1) does not significantly affect the abrasion of the tested concrete and fiber-reinforced concrete mixtures. With increasing the amount of cement, the wear resistance of concrete slightly increased (level G decreased by 3–9%). This effect is explained by the fact that, with the increase in the strength of concrete, which has a positive effect, the fragility of the cement–sand matrix simultaneously increases [3) to 1.6–1.8% of the cement weight also reduced the abrasion of concrete, which is explained by the increase in their strength. In this case, an improvement in the mechanical properties occurs due to the reduction in the W/C mixture. Most noticeably, by 9–14%, the abrasion of concrete decreased due to the use of polypropylene fiber in the amount of 1.8–2.2 kg/m3. Such an effect of dispersed reinforcement on wear resistance is explained by the ability of polypropylene fiber to hold individual concrete blocks as a composite material when applied under abrasive loads [The analysis of the diagram and ES model (6) shows that the cement content . Concrete mixtures with a maximum fiber content with a cement amount of 350 kg/m3 also had frost resistance grade F150 (No.4 and No.5). Composition No.7 also had frost resistance grade F150 with the cement amount of 400 kg/m3 and fiber content of 1.5 kg/m3, but with a minimum amount of superplasticizer. The remaining nine tested concrete compositions had F200 frost resistance. Thus, all concrete mixtures with a cement content of 450 kg/m3 had a higher frost resistance, which is an expected and widely described effect [3 and superplasticizer amount of 1.5% had F200 frost resistance. With the cement content of 400 kg/m3, compositions No.8, No.9, and No.10 with a fiber content of 1.5 kg/m3 or 3 kg/m3 and an average or maximum amount of superplasticizer (1.5% or 2%) had frost resistance grade F200. Thus, we can conclude that dispersed reinforcement has a positive effect on the frost resistance of concrete, which is also expected, coinciding with the results of most researchers [3) and an insufficient amount of superplasticizer (1%), the W/C of the mixture increased under the experimental conditions. In this case, the positive effect of the fiber was balanced by its negative effect on W/C. In general, it can be concluded that the average amount of fiber (1.5 kg/m3) with superplasticizer in the amount of 1.5% or more is reasonable for increasing the frost resistance of concrete.As shown in the data in d effect ,48,51. Wearchers ,52. The 3, leads to greater concrete strength in terms of wear resistance and frost resistance after 3 and 28 days.The studies carried out using the methods of optimal planning of the experiment made it possible to determine the complex effect of the amount of cement, superplasticizer, and polypropylene fiber on the strength, abrasion, and frost resistance of concrete for rigid pavements. A reasonable amount of fiber and superplasticizer is recommended. It was determined that the use of superplasticizer STACHEMENT 2570/5/G in the amount of 1.7–1.8% by the weight of cement, and polypropylene fiber with a length of 39 mm in the amount of 1.5–1.9 kg/m3 had a compressive strength of at least 65 MPa, a flexural strength of at least 6.0 MPa, frost resistance grade F200, and an abrasion rate of about 0.30 g/cm2. Concrete mixtures with these properties can be used for rigid pavements on all types of roads. Fiber-reinforced concrete with an increased amount of cement of up to 400–450 kg/m3 can be used in the construction of those sections of the road with the most load, which will provide greater structural reliability of pavement.When using a reasonable amount of dispersed reinforcement and superplasticizer, concrete mixtures even with a minimum amount of cement 350 kg/mIn general, the use of polypropylene fiber with a length of 39 mm and 0.45 mm with an equivalent diameter can be considered of limited effect for concrete mixtures under study. Dispersed reinforcement with this amount of fiber increased the compressive strength by 5–6% and the flexural strength by 8–12%, reduced the abrasion by 9–14%, and increased the frost resistance by up to 50 cycles. However, the use of this type of fiber can be recommended, since the achieved effect is complex, improving both the strength and durability of concrete. At the same time, the cost of this fiber is not high (about EUR 8 per kg), and in addition, fibers with such geometric dimensions do not significantly complicate the preparation of concrete mixture due to their easy distribution in the concrete volume. In addition, improving the properties of concrete for rigid pavements allows for the use of dispersed reinforcement in combination with a reasonable amount of superplasticizer.


Lacticaseibacillus paracasei Zhang (L. paracasei Zhang), using single-cell Raman spectroscopy (SCRS). Fluorescent microcopy with live/dead cell staining (propidium iodide and SYTO 9), plate counting, and scanning electron microscopy were used in combination to observe bacteria in an induced VBNC state. We induced the VBNC state by incubating the cells in de Man, Rogosa, and Sharpe broth (MRS) at 4 °C. Cells were sampled for subsequent analyses before VBNC induction, during it, and up to 220 days afterwards. We found that, after cold incubation for 220 days, the viable plate count was zero, but active cells could still be observed (as green fluorescent cells) under a fluorescence microscope, indicating that Lacticaseibacillus paracasei Zhang entered the VBNC state under these conditions. Scanning electron microscopy revealed the altered ultra-morphology of the VBNC cells, characterized by a shortened cell length and a wrinkled cell surface. Principal component analysis of the Raman spectra profiles revealed obvious differences in the intracellular biochemical constituents between normal and VBNC cells. Comparative analysis of the Raman spectra identified 12 main differential peaks between normal and VBNC cells, corresponding to carbohydrates, lipids, nucleic acids, and proteins. Our results suggested that there were obvious cellular structural intracellular macromolecular differences between normal and VBNC cells. During the induction of the VBNC state, the relative contents of carbohydrates (such as fructose), saturated fatty acids , nucleic acid constituents, and some amino acids changed obviously, which could constitute a bacterial adaptive mechanism against adverse environmental conditions. Our study provides a theoretical basis for revealing the formation mechanism of a VBNC state in lactic acid bacteria.This study aimed to investigate the molecular composition of a viable but nonculturable (VBNC) state of a probiotic strain,  Lacticaseibacillus paracasei Zhang  is a lactic acid bacterium isolated from traditional fermented mare milk in Inner Mongolia, China [L. paracasei Zhang strain has good acid resistance and bile salt resistance, strong abilities in immune regulation and antioxidation, and has been widely commercially used as a probiotic food additive and supplement [a, China ,2,3. Thipplement . Lactic pplement ,6. Howevpplement .Escherichia coli and Vibrio cholerae in estuaries and marine environments [The VBNC state was first reported in 1982 based on studies of ronments ,11. To dronments ,13,14. Nronments ,16. Thusronments . TherefoThe current methods for detecting VBNC cells include fluorescence microscopy coupled with staining kits, molecular detection techniques, and flow cytometry ,18. CellL. paracasei Zhang, to investigate its changes in intracellular macromolecules during the induction of a VBNC state. This study aimed to gain a better understanding of the VBNC state of lactic acid bacteria and provide a theoretical basis for revealing the formation mechanisms of a VBNC state in lactic acid bacteria.More than 95% of microorganisms in nature are in a VBNC state due to various environmental pressures. They cannot be isolated and cultured easily, leading to inadequate research on and utilization of these microbes . In addiL. paracasei Zhang was obtained from the Key Laboratory of Dairy Biotechnology and Engineering of Inner Mongolia Agricultural University, Ministry of Education, Lactic Acid Bacteria Culture Collection (LABCC). The strain was originally isolated from koumiss, a traditionally fermented mare milk product from Inner Mongolia, and its taxonomic identity was confirmed using biochemical, physiological, and molecular methods [The probiotic strain  methods . The bacL. paracasei Zhang was grown from the stock culture in 5 mL of de Man, Rogosa, and Sharpe (MRS) broth  at 37 °C for 18 to 22 h without shaking. A logarithmic phase culture of L. paracasei Zhang was washed twice in sterile saline (0.85% NaCl solution), resuspend in sterile MRS broth, and diluted to 107 cells/mL in saline to induce the VBNC state at various temperatures  . BrieflyL. paracasei Zhang cells were considered to have entered a complete VBNC state when the number of cells (per milliliter) determined by plate counting  was zero, while living cells (as green florescent cells) were still detected when observed under a fluorescence microscope (red fluorescence represented dead cells). The cell morphology was documented using scanning electron microscopy. For scanning electron microscopy, bacterial cultures were centrifuged at 1000× g at 4 °C for 10 min. The bacterial cells were washed 3 times with 10 mM phosphate buffered saline at 1000× g for 10 min. Next, the cells were fixed in 3% glutaraldehyde for more than 2 h, followed by washing 3 times with phosphate buffered saline and dehydration through the 10%, 30%, 50%, 70%, 80%, 90%, and 100% ethanol series. The dehydrated cells were dried by carbon dioxide under a critical point, then mounted, gold-coated, observed, and photographed with a scanning electron microscope  [The , Japan) .Healthy and VBNC cells were subjected to SCRS. Healthy cells were prepared by culturing the bacteria in MRS medium at 37 °C for 18 h when the culture entered the logarithmic growth phase. Among the 6 induction conditions, only cultures that were induced in MRS broth at 4 °C were found to enter the VBNC state and were thus further investigated by SCRS. Cell aliquots were collected at 4 time points (in triplicate) after starting VBNC induction , and the cells were centrifuged (5200 rpm × 3 min) at room temperature. Cells were washed three times with deionized water to remove the culture medium. Each sample was resuspended and transferred (1.5 μL) to a calcium fluoride microscope slide, and then air-dried for SCRS analysis. Raman spectra were obtained using a modified confocal Raman-fluorescent microscope  according to Wang et al. . Signals−1) was extracted for subsequent analysis and obtaining useful information in the Raman bands [Raw Raman spectra were pre-processed with the spectral software suite LabSpec 5 , including background subtraction and baseline correction by a second-degree polynomial algorithm; then, zero and area normalization were obtained . For eacan bands .L. paracasei Zhang cells were subjected to PCA, which was performed with Matlab R2016a [Normalized fingerprint ranges of the SCRS of normal and VBNC-state b R2016a . In PCA,L. paracasei Zhang was induced under different conditions , while other signal peaks were attributed to lipids , proteins , nucleic acid , and amino acids   bacteria and 1 peaks) . The finentrated , so the entrated .L. paracasei Zhang  were analyzed using PCA  and VBNC cells of sing PCA . On the L. paracasei Zhang was analyzed using PCA analysis. Symbols representing cells in the two different states were distributed in distinct clusters on the PCA score plot, suggesting that there were apparent cellular and metabolic differences , lipids (four peaks), nucleic acids (three peaks), and proteins (two peaks)  . We usedL. paracasei Zhang cells at different induction periods are shown in Differences in the molecular constituents  of healthy and VBNC −1 peak (corresponding to fructose) increased first and then decreased, with large fluctuations. Smaller fluctuations were observed in the 885 cm−1 and 1112 cm−1 peaks. The contents of most carbohydrate-related constituents increased significantly during the early stage of induction, which could be an adaptive response towards the adverse environment. Then, carbohydrates were gradually consumed and depleted. After the complete cell population entered the VBNC state, the carbohydrate content increased slightly; this was likely generated intracellularly to provide a minimal level of energy for survival. Previous reports found that several genes involved in carbohydrate and energy metabolism in yeast and bacteria were downregulated in the VBNC state [Carbohydrates are the most important constituents for discriminating between cell states, and they are the energy source used to maintain cell activity . The varNC state . HoweverNC state .−1 (corresponding to ν3PO43− group in phosphoric acid) and 1044 cm−1 (corresponding to a phospholipid group) were similar during the various VBNC induction stages, while the 1044 cm−1 peak showed greater variation between the different stages of VBNC induction. These molecular groups are important intermediates in lipid synthesis and decomposition. The intensity of the 908 cm−1 peaks (corresponding to myristic acid) exhibited only minor fluctuations during the VBNC induction stage, not showing obvious differences from healthy cells. The peak of 1065 cm−1 was attributed to palmitic acid, and its signal intensity increased first and then decreased. In the study of Yoon et al. [V. parahaemolyticus ATCC 17802 induced at 4 °C for 80 days had increased amounts of saturated fatty acids, such as lauric acid (C12), myristic acid, palmitic acid (C16), and stearic acid (C18), whereas the quantity of unsaturated fatty acids was reduced. Palmitic acid is involved in enhancing the tolerance of Vibrio parahaemolyticus to low pH, ethanol, and NaCl [The patterns of changes in the intensity of peaks of 860 cmn et al. , VBNC V.and NaCl ,46. The −1 peak fluctuated slightly in the induction process, while the intensity of the 1363 cm−1 and 1092 cm−1 peaks fluctuated to varying degrees during late and early induction, respectively. The 1459 cm−1, 1363 cm−1, and 1092 cm−1 peaks were assigned to deoxyribose in nucleic acid, guanine, and phosphoric acid, respectively. These three chemical structures are the main constituents of nucleic acids. Overall, the fluctuation in the Raman peak intensity of nucleic acids is relatively small, indicating a reduction in nucleotide synthesis activity in VBNC bacteria, which would possibly interfere with DNA replication and cell growth suspension. Indeed, most energy-dependent nucleotide biosynthesis pathways were found to be turned off after the bacteria entered the VBNC state [Then, changes in Raman peaks of nucleic acids during VBNC induction were analyzed. The intensity of the 1459 cmNC state ,48.−1 peak fluctuated significantly, while a smaller fluctuation was seen in the 950 cm−1 peak. The content of the ρ(CH2) group (corresponding to the 883 cm−1 peak) increased first, followed by a decrease during VBNC induction, then increased again at the end stage of VBNC induction. The Raman signal intensity of the single bond stretching vibration (corresponding to the 950 cm−1 peak) of the amino acids proline and valine showed only small variations during VBNC induction, but their expression decreased with the induction time. This might be a result of the continuous consumption of amino acids to support bacterial growth and survival. Postnikova et al. [Changes in the intracellular protein-related constituents during induction were then analyzed. The intensity of the 883 cma et al.  found thL. paracasei Zhang, a probiotic strain, using SCRS. Single-cell Raman spectroscopy is a powerful method for monitoring intracellular macromolecular changes, but has seldom been used for analyzing changes in the bacterial VBNC state. A previous study analyzed the metabolic changes in chlorine-stress-induced VBNC Pseudomonas aeruginosa, a potential pathogen [L. paracasei is a Gram-positive bacterium, and Pseudomonas aeruginosa is a Gram-negative bacterium, it would not be surprising if the two bacteria underwent different metabolic changes when tranitioning into a dormant VBNC state. The work of Qi and Liu (2022) [d-alanine, glutathione, and N-Butanoyl-d-homoserine lactone) between normal and VBNC cells. Although only one common differential intracellular constituent  was identified in the two studies, both works consistently found that VBNC bacteria maintain low metabolic activity and exhibit obvious intrapopulation-level metabolic heterogeneity.Food-use bacteria often face extensive environmental stress during the food production process, and some of them may enter the VBNC state. However, few studies have systematically elucidated the physiology of the VBNC state of food-use or probiotic bacteria. Thus, this study investigated the metabolic properties of VBNC pathogen . The compathogen  is that pathogen  found thpathogen  observedu (2022)  identifiL. paracasei Zhang, as a model. The Raman spectrum analysis found obvious differences in the levels of various intracellular constituents  between normal and VBNC cells, which are useful in distinguishing between cell states. Raman spectroscopy generates intracellular macromolecular profiles without any fixation or labelling, thereby allowing the monitoring of live single cells without sacrificing their viability or causing any physiological damage. In short, our study explored the VBNC state of lactic acid bacteria using Raman spectroscopy. The current study provides a theoretical basis for revealing the formation mechanism of the VBNC state in lactic acid bacteria; it also demonstrates the usefulness of Raman spectroscopy in detecting macromolecules at the single-cell level without any labels.This study investigated the VBNC state of lactic acid bacteria using a well-studied probiotic bacterium, namely


Antibiotic exposure in pregnancy is associated with reduced microbiome diversity in the infant gut. Given that recent research has shown that early microbiome health can impact child socioemotional development, we examined the relationship between prenatal antibiotic exposure in pregnancy and childhood socioemotional developmental outcomes using a large, nationally representative longitudinal dataset.A sample of 4800 diverse families were assessed from the population cohort of the Growing Up in New Zealand Study (GUiNZ), which prospectively follows children starting in the last trimester of pregnancy into early childhood. Socioemotional development was measured using a composite score derived from seven commonly used socioemotional tasks administered between 9 months and 4.5 years of child age, addressing emotional expression understanding, regulation of emotions and behavior, and social problem solving and relationship skills. A national comprehensive pharmaceutical database was used to determine children's prenatal antibiotic exposure. Multivariate linear regressions models were used to examine the effects of the timing (trimester) and dosage (number of courses) of prenatal antibiotic exposure on socioemotional development, with and without statistically adjusting for confounding factors addressing maternal health, socioeconomic status, maternal age, and child sex.β ≤ −0.02).In unadjusted analyses, antibiotic exposure was inversely associated with child socioemotional development. However, after statistically adjusting for important confounds, socioemotional development was not associated with prenatal antibiotic exposure at any dosage or trimester of pregnancy (all Prenatal antibiotic exposure does not appear to impact early childhood socioemotional development. Maternal health and sociodemographic factors are confounded with antibiotic exposure and socioemotional development, a fact that should be considered in future research examining the effects of prenatal antibiotic exposure on child health. These findings may be reassuring to families who are concerned about the long‐term effects of antibiotics in pregnancy on child health outcomes. Many women receive antibiotics during pregnancy. While medically necessary, antibiotics can disrupt the mothers' microbiome, and recent research suggests that it may also alter the infants' microbiome, although very few studies have investigated long‐term outcomes in children exposed to prenatal antibioticsUsing a large longitudinal dataset, prenatal exposure to antibiotics did not adversely impact child socioemotional outcomes once important confounders like maternal health and sociodemographic factors were taken into accountFuture research should examine whether prenatal antibiotic exposure impacts other domains of development, and include high‐risk populationsA healthy microbiome is essential for infant health, helping to protect against harmful microbes, regulate metabolism, and improve homeostasis of the immune system  longitudinal cohort study. GUiNZ enrolled a cohort of 6853 pregnant mothers between 2009 and 2010. The team collected data in the last trimester of pregnancy, and postnatally at 9 months, 2 years, and 4.5 years of child age. Pregnant women were recruited by health professionals or GUiNZ recruiters in medical and community settings , and informed consent was obtained from primary caregivers for use of interview and linked prenatal antibiotics use data., a national dataset that includes all prescription medication dispensed by pharmacists in New Zealand . A full description of the collection of antibiotics data for the GUiNZ study are reported in Hobbs et al. (antibiotic courses) and during each trimester.Information regarding exposure to antibiotics was determined by linkage of the GUiNZ participant data with the Pharmaceutical Collections et al. . Brieflys et al. . Any antz‐scored. Socioemotional scores ranged from 35 to 147 , with higher scores indicating higher socioemotional development. The index allows for the use of SD to categorize levels of socioemotional development, however, in our analysis, we used this index as a continuous score to highlight the spectrum of socioemotional development.Given that socioemotional development is a multifaceted construct, socioemotional development was measured across the early childhood period using a composite index developed by the GUiNZ team. Full details regarding how the socioemotional development index was developed and validated can be found in Peterson et al. . BrieflyConfounders were selected because they had been shown to predict either antibiotic use or child socioemotional development in previous research . Finally, we used multivariable models to examine whether any observed association between antibiotic exposure in pregnancy and socioemotional development remained statistically significant after adjusting for potential confounders. Linear regression was used in cases of continuous outcome variables  and binominal logistic regression was used in the case of dichotomous outcomes . All analyses were performed in SPSS version 19.0. Given the large sample size, antibiotic effects were considered statistically significant with p < 0.01.We employed a three‐step statistical strategy. First, unadjusted linear regression models were used to test whether antibiotic exposure in pregnancy predicted childhood socioemotional development. Second, we constructed multivariable linear regression models using antibiotic exposure and socioemotional development as outcomes to identify potential sociodemographic confounders. Any confounder that significantly predicted either antibiotic exposure or socioemotional development in multivariable models was examined as a potential confounder . To make a more direct comparison to rodent studies, future observational research could be conducted with higher risk populations, such as pregnant women with chronic bacterial infections that require frequent antibiotics throughout pregnancy. Another reason why our results may differ from those of animal studies is that it is difficult to do experimental paradigms on antibiotic use in humans and, as our study shows, antibiotic use in humans is confounded with sociodemographic outcomes and maternal health.Our results suggest that caution should be used before extrapolating the results from rodent studies of prenatal antibiotic exposure directly to humans, especially given that the dosages are often quite different. For example, in a rodent study that examined the impact of prenatal antibiotic exposure on offspring behavior, 7‐day courses of antibiotics were administered to pregnant mice , and informed consent was obtained from primary caregivers for use of interview and linked prenatal antibiotics use data.Adi Fish‐Williamson conceptualized the research question, primarily wrote the manuscript, and performed statistical analyses. Dr. Jan Wallander contributed to data interpretation and assisted in manuscript preparation. Dr. Mark Hobbs assessed with data‐processing and consulted on research design. Dr. Susan M. B. Morton oversaw data‐collection. Dr. Jennifer Hahn‐Holbrook closely oversaw all statistical analyses and manuscript writing. All authors contributed to revisions of the manuscript and have approved the final manuscript.TABLE S1Click here for additional data file.


The COVID-19 Community Research Partnership (CCRP) is a multisite healthcare system-based study of the COVID pandemic. Community residents in this study provided consent for electronic health record (EHR) access allowing for analysis of antibiotic prescribing.We conducted a retrospective, self-controlled cohort study to determine antibiotic consumption in the CCRP pre-COVID (Jan 2018 - Dec 2019) and post-COVID (Jan 2020 - Jan 2022). Participants were ≥18 years with an EHR record in the pre-COVID period. The primary outcome was the number of antibiotic prescriptions (AP) per 1000 patient care encounters in each time period. Secondary outcomes included the AP location of care, analysis of antibiotic classes, and COVID attributable antibiotic consumption, defined as an AP written ≤14 days before or after an EHR documented or self-reported positive SARS-CoV-2 test or COVID diagnosis.34,234 participants were included representing 2,775,711 encounters. Median age was 53 years with 70% female and 88% white. 41% lived in a rural or suburban area. There were 26,121 APs among 25,433 participants. Mean rate of AP per 1000 encounters was 12.1 and 7.6 pre vs post-COVID (p< 0.001). A decline in AP occurred at onset of the pandemic persisting through the post-COVID period . The prescribing rate for all antibiotics, except linezolid, decreased during the pandemic . The largest declines were seen with antibiotics typically prescribed for respiratory illnesses. The decline in antibiotic consumption was driven by outpatient encounters . 6,341 participants were diagnosed with COVID and 333 APs were COVID attributable. These participants were more likely to receive a macrolide , live in a rural area , and receive care in an emergency department .Figure 1.Antibiotic Prescriptions During The Study Time PeriodFigure 2.Analysis Of Antibiotic ClassesFigure 3.Location of Antibiotic PrescribingThe COVID pandemic was associated with a broad decline in antibiotic consumption. These results may be due to declines in other respiratory viruses, anchoring bias for COVID during the pandemic, improved antibiotic stewardship practices, or social isolation. Antibiotics for respiratory illnesses declined the most, suggesting this may be a target for outpatient stewardship efforts.All Authors: No reported disclosures


Caption: Grow‐out ponds for GIFT Nile tilapia, Malaysia.Credit: Trong Trinh (WorldFish).


Additionally, the optimized RPC stood out due to the enhanced rheological behavior, influenced by the lubricative properties of calcium carbonate and the water conservation features of the glass powder. The reactive properties of SF, combined with GP, brought distinct performance variations, most evident at 28 days. Yet, both mixtures exhibited superior resistance to chloride, deeming them ideal for rigorous settings like coastal regions. Significantly, the RPC iteration, enriched with selective mineral admixtures, displayed a reduced tendency for drying-induced shrinkage, mitigating potential crack emergence.In pursuit of developing an eco-friendly and cost-effective reactive powder concrete (RPC), we utilized a multi-objective optimization technique. This approach pivoted on the incorporation of byproducts, with a spotlight on ground glass powder (GP) as a pivotal supplementary cementitious material (SCM). Our goal was twofold: engineering cost-efficient concrete while maintaining environmental integrity. The derived RPC showcased robust mechanical strength and impressive workability. Rigorous evaluations, containing attributes like compressive strength, resistance to chloride ion penetration, ultrasonic pulse speed, and drying shrinkage, highlighted its merits. Notably, the optimized RPC, despite an insignificant decrease in compressive strength at 90 days compared to its traditional counterpart, maintained steady strength augmentation over time. The refinement process culminated in a notable 29% reduction in ordinary Portland cement (OPC) usage and a significant 64% decrease in silica fume (SF), with the optimized mix composition being 590 for cement, 100 for SF, 335 for GP, and 257 kg/m The increase in greenhouse gas emissions from ordinary Portland cement (OPC) has led to a growing demand for sustainable cementitious materials. Cement production is responsible for more than 8% of the world’s carbon dioxide emissions, making it crucial to reduce its environmental impact ,2. DevelAlthough RPC has been widely recognized as a superior material for construction, its production has been limited in many countries, particularly in developing nations, due to several factors. As noted by Peng et al.  and MayhFurther from the carbon footprint problems, the increased cement need in RPC has various negative implications on the performance of the concrete due to shrinkage and microcracking concerns . FurtherSeveral researchers have conducted experimental works to analyze the effect of SF dosage on the properties of reactive powder concrete (RPC) . AccordiOn the other hand, as recycled glass (GP) is used progressively more, the capacity of landfills to properly handle it and dispose of it permanently is being exceeded . It is dNumerous studies in the sector have recently focused on recycled glass as a potential concrete component to enhance its qualities, affordability, and carbon footprint. According to Kaminsky et al. , the proDu and Tan , who exaAl-Awabdeh et al.  used a wDue to the alkali nature of glass and its high silica content, which is primarily in the amorphous condition, the alkali–silica reaction (ASR) is an expected but adverse behavior that must be properly handled when adding glass waste into the manufacture of concrete. ASR is mostly detected in the later phases of curing as a formation of cracks and expansion of the cement matrix, which ultimately can cause considerable structural damage . HoweverOn the other hand, the mechanical properties of ultra-high-strength concrete with particle packing density, such as RPC, may benefit from GP, according to some research. For example, in order to partially substitute cement in RPC, Hussain et al.  used GP,Furthermore, multiple research projects have been conducted to explore the impact and synergistic effects of various SCMs, in addition to SF, in the construction of environmentally friendly RPC concrete ,40,41. BDespite its benefits, RPC has two key drawbacks: a high cost and a large carbon impact. Numerous research has looked at the use of inexpensive, ecologically benign, and locally accessible minerals as additives in RPC combinations ,21, but Numerous endeavors have been made to refine RPC formulations, yet the current research uniquely pivots towards the incorporation of eco-friendly components like waste glass and micro calcium carbonate. Hence, we not only advocate for pioneering waste management solutions but also underscore the significance of sustainable construction methodologies. Beyond formulation, we have explored the performance metrics of these novel RPC mixtures, spanning from their workability to their durability under various conditions, such as chloride ion exposure. The utilized methodology, underscored by the adoption of the Modified Andreasen and Andersen (MAA) model, offers a robust approach to assessing particle distribution and density, amplifying the reliability of the outcomes.50 of 0.15 μm. Additionally, silica sand was used, which has a d50 of 165 m, a maximum particle size of 600 μm (dmax), and a specific density of 2.65. In order to lower the cement and SF content, calcium carbonate powder (CaC) and waste glass powder (GP) were added to the optimal dose. CaC has a d50 value of 2 μm and a specific density of 2.74; the d50 value for glass powder was 28 μm. The specific density of both of the glass powders was 2.61. The results of particle size distribution (PSD), the mineralogical investigations carried out using X-ray diffraction (XRD), and the scanning electron microscopy (SEM) study of the constituents are shown in The RPC doses were made using raw components from the Colombian market. The cement had a mean particle size of 9 μm and a specific density of 3.14. The employed SF conformed to ASTM C-1240  and had The superplasticizer employed in this study was a high-range water reducer admixture (HRWR) based on polycarboxylate ether. It had a solids concentration of 40% and a specific gravity of 1.07.The packing density of the granular ingredients, especially powders, is crucial for designing an efficient RPC combination ,45. The The design of the experiment is a key component of statistical analysis that seeks to identify relevant factors and their impact on various attributes. The purpose of this research is to provide insight into the changes in RPC properties when SCMs are added to a conventional concrete mixture. The goal is to conduct as few tests as possible while keeping detailed information on the factors, their interactions, and their impact on the responses. An appropriate experimental zone is identified using response surface methodology (RSM).Various methods for data collection can be examined using response surface methodology (RSM), in this case, central composite design (CCD) was selected for the mixing design since it stands out as the most efficient and commonly used in experimental studies. Its advantages include rotatability, exact estimations in all directions, and the ability to generate predictions that lie within the experimental range ,52,53. IFollowing previous works , the val3 [A], the water-to-binder ratio [B], and the volume ratio of HRWR (high-range water reducer) [C]. The MAA hypothesis is used to determine the remaining RPC component proportions. This study takes four repetitions of the central point into account. The design involves three factors: the amount of OPC (ordinary Portland cement) in kg/mFor the final analysis, a multi-objective optimization model is suggested in which concrete features such as self-compacting behavior, compressive strength, and low cement content are treated as response variables, and significant parameters are manipulated as input variables. This sort of optimization employs an analytical method based on the desirability function introduced by Derringer and Suich , which iThe abovementioned criteria optimization allows for the determination of proposed input variable values that can satisfy the desired conditions in response variables. These determined positions, known as simultaneous optimal points, may or may not always coincide with the control parameters. They are, instead, an achievable option that keeps all related variables within acceptable limits .To begin the mixing process, the HRWR and water were combined and mixed at a minimum speed for 90 s. Afterward, the previously mixed binders were added to ensure homogeneity during mixing. The blending process continued until the mixture achieved a flowing consistency, which typically took 3–5 min, depending on the RPC mixture. Once the desired fluidity was achieved, the mixture was mixed at medium speed for 60 s. Next, the equipment was stopped, and the mold was scraped, after which the mixing process resumed for 180 s at high speed. Silica sand was then added and mixed for 60 s at a slow speed before the mixing process was completed at medium speed for an additional 4 min. The workability of each mixture was evaluated using the guidelines outlined in ASTM C1437 .After the workability test, 50 mm mortar specimens were prepared in accordance with ASTM C109 , while cIn this study, fresh and hardened concrete characteristics were used to assess the quality of sustainable concrete. Three samples were tested for each test, and the results were averaged. The workability of each mixture was evaluated using the guidelines outlined in ASTM C1437 . For expA drying shrinkage test was conducted on three samples for each mixture according to the guidelines of ASTM C490 . The temReactive powder concrete (RPC) was at its fresh stage, and the effects of components A, B, and C on the slump flow are shown in 2O in the GP used in UHPC mixtures  and the concentration of HRWR (factor C). Among these factors, w/b exerts the most significant influence in the current analysis. However, it should be noted that the high w/b ratio has a detrimental impact on the compressive strength, thus necessitating the consideration of a balanced approach, which will be discussed further below.Workability increases in direct proportion to the increase in the w/b ratio, with no discernible impact from fluctuations in the percentage of HRWR. When low levels of HRWR are maintained, the concrete has poor workability at all dosage levels. If workability were the only consideration, maintaining values above the center points for the w/b ratio and HRWR would suffice, especially when using a low cement dosage. However, from a financial sense, this strategy may be impractical. As a result, the following part examines the same conditions in order to determine the ideal factor conditions inside the mix while adhering to the previously set limits.A second-order model was generated using the workability response model, as shown in The average CS at 1, 7, and 28 days are shown in According to Wang et al. , using p3, respectively) and when factor B is equal to a -α (0.156), according to the response surface for compressive strength at 28 days.Moreover, too much of this chemical additive (polycarboxylate-based superplasticizer) might make reactive powder concrete (RPC) in its fresh condition stickier than preferred. The maximum compressive strength is attained when factors C and A are both equal to α  and silica fume (SF) does not compromise three important features that have a substantial impact on material performance. These characteristics include: (i) achieving proper particle packing density using particle packing theories, (ii) using suitable high-range water-reducing polycarboxylate-based superplasticizers that allow for a low water-to-binder ratio (w/b), and (iii) ensuring proper chemical reactions among components, such as hydraulic and pozzolanic reactions, to generate adequate gel products ,71.On the one hand, the presence of GP 28 in the particle size distribution (PSD) curve  helps to2O , both showing a normal growth of strength . SimilarThe growth rate ratio between the control sample and the optimized mixture decreased over time, reaching a similarity between 28 and 90 days, as depicted in At the 28-day mark, there is a noticeable difference between the control and optimized doses , which mThe improved mixture’s chloride ion penetration was found to be 2.1 times more than that of the control test after 90 days of testing. However, both RPC combination compositions showed insignificant measurements at 28 and 90 days, demonstrating CaC and GP’s outstanding behavior. As a result, it may be inferred that the improved RPC may be used in constructions that must withstand harsh circumstances, such as those prevalent in coastal locations ,79,80. AA consistent and gradual rise in results is seen over the range of testing ages for ultrasonic pulse velocity analysis. As shown in According to Overall, compared to the control test, the improved RPC mixture showed a decreased descent in its shrinkage curve for various measurement ages. This behavior could be attributed to a number of factors, such as slower volumetric changes at young ages, partial replacement of OPC and SF with mineral additives , decreasBased on the above, it could be inferred that the partial replacement of OPC and SF with mineral additives effectively reduces drying shrinkage, hence lowering the risk of fracture and micro fissure development in the RPC mass.3. In contrast, the optimized mixture manifested a cost of just 314.2 $/m3, showcasing an appreciable decrease. When quantified, this difference translates to a substantial cost reduction of roughly 27.8% or 120.9 $/m3. The data underscores not only the economic advantages inherent in adopting an optimized mixture but also hints at potential enhancements in both its performance and eco-friendliness. The financial ramifications of such a reduction become even more profound when applied to large-scale construction endeavors. This observation, in essence, underscores the pivotal role of continual research and innovation in paving the way for more economically viable and efficient construction materials.A multi-objective simultaneous optimization methodology was adopted in this study to create a financially viable and environmentally sustainable reactive powder concrete (RPC). The strategy included the use of byproducts, such as ground glass powder (GP) as an SCM, with the goal of producing a cost-effective and environmentally friendly concrete that meets many objectives at the same time. The produced material had desirable workability and mechanical properties. The optimized RPC combination from the response surface method was subjected to extensive testing, which included measurements of compressive strength in cylinders, chloride ion penetration, ultrasonic pulse velocity, and drying shrinkage.The results from this study emphasize the need for overseeing components such as cement dosage, water-to-binder ratio, and superplasticizer content in order to improve RPC’s early and long-term compressive strength while also taking workability and other crucial variables into consideration. The optimized reactive powder concrete (RPC) mixture had a slightly lower compressive strength at 90 days than the control mixture, but both showed normal strength growth over time, with the optimized mixture demonstrating an acceptable performance when mineral admixtures such as cement replacements and silica fume were used. Using powdered granulated blast furnace slag (GP) in ultra-high-performance concrete (UHPC) mixtures can cause an alkali–silica reaction, which has a direct effect on the mixture’s capacity for compressive strength. In influencing the slump flow of reactive powder concrete (RPC) at its fresh stage, the water-to-binder ratio (w/b) is a critical factor. It displays a distinct linear relationship with the slump flow, demonstrating its major impact on workability.The use of superplasticizers based on polycarboxylates stimulates the formation of calcium-silicate-hydrate (C-S-H), which improves the microstructure of the cementitious matrix. It also has an effect on silicate hydration and ettringite production. However, too much of this chemical addition might cause stickiness in fresh RPC.When compared to the control mixture, the optimized reactive powder concrete (RPC) dosage has a lower water-to-binder ratio and superplasticizer concentration, which is influenced by factors such as silica fume-specific surface area, the reduced presence of free water, the lubricating effect of calcium carbonate (CaC), and the water-reducing and dispersing properties of glass powder, resulting in improved rheological performance.The pozzolanic activity of silica fume and waste glass resulted in noticeable differences between the optimized reactive powder concrete (RPC) mixture and the control mixture at the 28-day mark; however, both mixtures demonstrated satisfactory performance over time, with improved chloride ion penetration resistance and reduced permeability to chloride ions, making it suitable for construction in harsh environments such as coastal areas.The optimized reactive powder concrete (RPC) with partial substitution of OPC and SF by mineral admixtures showed less drying shrinkage than the control RPC dosage, resulting in slower volumetric change at early ages and a lower likelihood of the formation of cracks and microcracks, highlighting the effectiveness of mineral admixtures in minimizing essential drying shrinkage and improving RPC’s mass integrity.To summarize, as the inclusion of SCMs in the RPC mixture can influence the hydration kinetics and microstructure of the material, future research should strive to understand the underlying chemical mechanisms, hydration products, and pore structure evolution of blended RPC in order to improve its overall performance and potential considering the previously identified limitations and constraints. This analysis would play a role in ensuring a balanced strategy that meets both workability and financial goals.In the current phase of our investigation, we have focused on an RPC formulation that uniquely incorporates waste glass and micro calcium carbonate. While our assessments have been confined to laboratory settings, the initial findings, including notable workability and compressive strength, hint at its viability for real-world engineering scenarios. This RPC not only offers an eco-friendly construction alternative by repurposing waste, but also presents potential economic efficiencies by substituting pricier traditional elements. Furthermore, its robust performance metrics, such as resistance to chloride infiltration, suggest broad applicability in diverse construction contexts, marking a significant stride in sustainable infrastructure development.Future research could further explore alternative materials and methodologies to enhance the properties of RPC beyond those of traditional concrete. Exploring the incorporation of nanomaterials, diverse fiber types, or supplementary cementitious materials offers promising avenues. Furthermore, refining mixing protocols, curing processes, and particle packing strategies may lead to significant advancements.