The consumption of structural concrete in the construction industry is rapidly growing, and concrete will remain the main construction material for increasing urbanization all over the world in the near future. Meanwhile, construction and demolition waste from concrete structures is also leading to a significant environmental problem. Therefore, a proper sustainable solution is needed to address this environmental concern. One of the solutions can be using recycled coarse aggregates (RCA) in reinforced concrete (RC) structures. Extensive research has been conducted in this area in recent years. However, the usage of RCA concrete in the industry is still limited due to the absence of structural regulations appropriate to the RCA concrete. This study addresses a safety margin of RCA concrete beams in terms of shear capacity which is comparable to natural coarse aggregates (NCA) concrete beams. To this end, a database for reinforced concrete beams made of recycled coarse aggregates with and without shear reinforcement was established, collecting the shear specimens available from various works in the existing literature. The database was used to statistically identify the strength margin between RCA and NCA concrete beams and to calculate its safety margin based on reliability analysis. Moreover, a comparability study of RCA beams was conducted with its control specimens and with a database for conventional RC beams. Concrete is one of the most widely used construction materials, and its demand has been significantly high and will even grow with rapid economic development and urbanization. Concrete mainly consists of coarse aggregates which account for around 70–80% of the volume of the concrete mixture. Thus, the coarse aggregate plays a significant role in the strength and performance of concrete members. Meanwhile, the global demand for new aggregates which are incorporated in the concrete mixture is estimated to exceed 40 billion tons annually as new concrete structures are constructed. Recycling the waste concrete for use as coarse aggregates is a sustainable solution to address the main two environmental concerns related to the depletion of natural aggregates and landfill capacity. However, it has been reported that the presence of old mortar on the surface of the recycled coarse aggregate (RCA) adversely affects its physical and mechanical properties ,4,5. TheSince the shear failure of reinforced concrete (RC) has a brittle nature, it can be critical unless the concrete member is properly designed against shear considering the material characteristics. Furthermore, the shear resistance of concrete members significantly depends on the aggregate interlocking at the crack surface. Thus, the inferior properties of recycled coarse aggregates negatively affect the aggregate interlock and may reduce the shear resistance . AlthougRecently, experimental and statistical approaches have been conducted ,9, and tA database was compiled from available studies on the shear strength of RCA concrete beams with and without shear reinforcement. A review of existing studies revealed that a total of 591 specimens from 41 studies ,47,48,49The specimens were rigorously selected from the database through a detailed filtration process to ensure that the experiments were well-executed, and the specimen details are in practical range. Since only slender beams were analyzed in this study, the following selection criteria used by Reineck et al.  and Dunkstrength . When thconcrete . To ensuFinally, 360 specimens were sorted out among all the collected RCA specimens. The numbers of specimens with and without shear reinforcement are 96 and 264, including control specimens, respectively, as shown in To investigate the implication of recycled coarse aggregates on the shear capacity of reinforced concrete beams, the shear strength ratio between the RCA specimen and its control specimen ( studies ,55 have The shear equation specified in ACI318-19 for estimating the shear resistance consists of contributions of concrete (According to ACI318-19, the maximum allowable Meanwhile, it was observed that shear capacities reported in papers are fluctuating from approximately 30% reduction to 40% improvement compared to those of control specimens which are NCA concrete beams. These fluctuations may be caused due to different recycling methods, quality of coarse aggregate, concrete mixture, and human and instrumental errors. Moreover, there are some cases where only one experimental datum was available for each replacement ratio in the database, for example, 5%, 23%, 47%, etc. The limited number of tests may lead to the misinterpretation of experimental results, as it is impossible to verify or check human and instrumental errors in these cases. Thus, the specimens were categorized into several groups, according to the replacement ratio to eliminate those uncertainties and differences during quantitative analysis. The mean values were calculated according to the groups of replacement ratio, as presented in A statistical approach was used to investigate whether there is any statistically significant difference between the recycled coarse aggregate and natural coarse aggregate concrete beams. The normalized shear strength ratio was taken in this analysis, as most of the code provisions use the square root of the compressive strength of concrete (d t-test  is a comd t-test , which ip-value of 0.9917. The p-value is the probability of rejecting a correct null hypothesis (p-value, the more it supports p-value is more than the alpha value of 0.05 for the right-tailed test with a confidence level of 95%. This confirms a null hypothesis that the mean of the normalized shear strength of the group for 1~30% is lower than control specimens. The analysis results of the Shapiro–Wilk test showed that differences between pairs can be assumed approximately normally distributed. Moreover, the absence of outliners was confirmed by the Tukey Fence method [p-values for these groups for 31~50% and 51~100% were 0.9954 and 0.9985, respectively. From the analysis, it can be concluded that the abovementioned observations about the reduction in shear capacity are statistically confirmed with a 95% confidence level. RStudio is an integrated development environment for so-called R , a progre method , which ip-value is 0.7937, which is larger than the alpha value of 0.05. The average population for RCA concrete beams is assumed to be equal to that of NCA concrete beams. In other words, the difference between the averages for RCA and NCA is not large enough to be statistically significant. The analysis results of the Shapiro–Wilk test showed that differences between pairs cannot be assumed as a normal distribution with a moderate violation; that is, the violation of normality assumption is not that significant. Moreover, the paired t-test is considered robust for moderate violation of the normality assumption. The p-value for the group for 51~100% was 0.8412. From the analysis, it can be concluded that the average population of RCA and NCA concrete beams can be statistically considered equal with a 95% confidence level.The analysis result of paired t-test showed that the Although the introduction of the recycled coarse aggregate leads to a reduction in the shear capacity of reinforced concrete beams, only an average 6% reduction may not have a significant effect on design safety when considering the inherent uncertainties in the shear mechanism. In addition, the code provisions are conservatively established to estimate the shear capacity of the RC beams. Thus, a reliability analysis was conducted to check this point and proposed an appropriate strength reduction factor for the shear design of RCA concrete beams if required. To investigate whether a new reduction factor should be introduced in designing RCA concrete beams against shear, the reliability index (’s study , as presThe FORM analysis was carried out by utilizing the probability distribution of the random variables which are used to calculate the nominal shear strength and the limit state function. Based on these calculations, the reliability index was identified for all the beams in the database. The first-order form of limit state function can be written as follows:The reliability index (In this section, the shear strengths of RCA concrete beams are compared with those of RC beams from a well-established database. The RC database was taken from Yerzhanov and Lee’s study , and it For beams without shear reinforcement, a comparability study of RCA and NCA beams showed that the introduction of recycled coarse aggregate will result in shear capacity reduction. The same result was shown in statistical analysis, which stated that these reductions are statistically significant. However, the values of these reductions are only 1.6%, 4.1%, and 5.9% for 1~30%, 31~50%, and 51~100% replacement ratios, respectively. Therefore, it was assumed that these small fluctuations will be negligible in terms of member safety. To check it, a reliability analysis was conducted. It showed that the mean reliability index is 5.95, which is higher than the ACI target reliability index. Moreover, RCA performance was compared with RC. The comparison showed that there is no difference between them in terms of strength capacity, as well as reliability index. It can be concluded that the clear reduction in shear capacity can be neglected due to its small value and conservativeness of the current ACI equation. Therefore, we propose using the same equation for RC and RCA beams. There is a clearer picture for beams with shear reinforcement. Comparability study of RCA and NCA beams showed mean values are quite close to unity, 2.6% increase and 0.1% reduction for 1~50% and 51~100% replacements, respectively. Statistical analysis also showed that the difference is not statistically significant. A comparability study between RC and RCA confirmed that there is no considerable difference in shear capacity. It can be explained that coarse aggregate only affects the shear resistance of concrete. Therefore, the effect of recycled coarse aggregate becomes negligible.The comparability study of RCA concrete beams with its control specimens showed that there is a small reduction in the shear capacity of RCA concrete beams. Moreover, the capacity reduction grows as the replacement ratio increases, and it was much less for the beams with shear reinforcement.For beams without shear reinforcement, a paired t-test confirmed the difference between RCA concrete specimens and its control specimens. It was statistically proven that the average shear capacity of RCA beams is lower than that of NCA beams. On the other hand, the paired t-test showed that there is no statistically significant difference between RCA and NCA concrete beams with shear reinforcement.The reliability analysis showed that the shear strength equation of current ACI 318-19 can be used for the shear design of RCA beams with a desirable safety level.A comparability study with well-established RC beams indicated that there is no difference in shear capacity between RCA and RC databases. Moreover, RCA concrete beams follow general trends and safety margins, which are set for conventional reinforced concrete members, regardless of key influencing factors or reliability index.This study only focused on the shear strength of RCA concrete beams, not structural behavior. Thus, the structural performance of the RCA concrete beams could be further studied in terms of shear behavior related to stiffness, ductility, and even durability.In this study, the performance of RCA concrete beams was assessed regarding its shear capacity, for which an extensive literature review was conducted and an up-to-date database for RCA concrete beams was established. The analysis of the established database allowed us to draw the following conclusions:


IgG4 related disease (IgG4-RD) is a systemic autoimmune disease characterized by tissue invasion with IgG4-producing plasma cells, resulting in tissue dysfunction. IgG4-RD can affect the kidney in various forms, including renal mass, tubulointerstitial disease, and glomerulonephritis. IgG4-RD can mimic other autoimmune diseases and neoplasms, and as such, maintaining a high index of suspicion is the key to timely diagnosis and treatment. In this paper, we present a case of IgG4-RD that presented with pseudotumor and severe renal dysfunction that progressed to end-stage kidney disease (ESKD), associated with a rare finding of renal vein thrombosis (RVT). IgG4 related disease (IgG4-RD) is a multisystem autoimmune disorder characterized by tissue infiltration with IgG4 producing plasma cells, resulting in organ dysfunction -2. IgG4 Low-dose glucocorticoids are the first-line treatment for IgG4-RD, and timely diagnosis and therapy can avoid unnecessary surgery and preserve organ function. Most patients achieve partial or complete remission; however, up to 35% of patients relapse once steroids are tapered off and require further treatment with other agents such as Rituximab ,4.We describe a case of IgG4-RKD manifesting with renal dysfunction and a renal mass that progressed to End-Stage Kidney Disease. We also report the unique finding of left renal vein thrombosis (RVT), which to our knowledge, has never been described previously with IgG4-RKD.A 55-year-old lady presented with acute kidney injury (AKI). Her history was unremarkable, she was not on any medication, and she had no constitutional symptoms. Her Blood Pressure (BP) was elevated, 197/110, but the rest of her vital signs and physical were normal. The patient's laboratory investigations upon admission are shown in table Abdominal ultrasound showed increased renal echogenicity with an atrophied left kidney. The right kidney measured 12 cm with two hypoechoic lesions, one at the interpolar area measuring 2.5x 2 cm and one at the lower pole measuring 2.5 x 1.6 cm  or fungal infection Figure .Due to the uncertainty, a percutaneous needle biopsy was obtained. The biopsy showed severe interstitial lymphoplasmacytic infiltration with severe interstitial fibrosis and tubular atrophy Figure , 4B, stoUpon request, immunohistochemistry staining showed more than 20 IgG4-positive plasma cells per high power field Figure .Due to severe renal impairment, hemodialysis was initiated along with prednisone 0.6 mg/kg. Unfortunately, she remained dialysis-dependent after one month of steroid therapy. Nevertheless, the renal mass, lymphadenopathy, and portahepatis cyst resolved in follow-up CT (Figure In this paper, we report a case of IgG4-RKD with pseudotumor and RVT that progressed to ESKD. To our knowledge, only 3 cases have been reported in Saudi Arabia -7. We beIgG4-RD typically affects middle-aged to older-age individuals, with male predominance . MaintaiAlthough our patient had strongly positive ANA and Anti-DNA serology, the absence of extra-renal manifestation of lupus, normal complements level, and glomeruli spares make lupus nephritis unlikely. However, the lupus markers would need to be followed up periodically.Previous reports have shown that renal involvement in IgG4-RKD is commonly accompanied by other organ involvement . A diffeThe IgG4-RD has been thought to follow a relatively benign course; however, some patients can develop a poor outcome. In one case series of 35 patients with IgG4-RKD, two patients required hemodialysis and progressed to ESKD, despite corticosteroid therapy . InteresWe believe that the lack of response to steroids was due late presentation of severe IgG4 disease, as evidenced by the presence of extensive tubulointerstitial infiltration and severe interstitial fibrosis. The diagnosis of IgG4-RKD that manifests with a renal mass is often made after nephrectomy . MaintaiLastly, our patient developed left RVT, possibly as a complication of IgG4-RKD. Thromboembolic events in the setting of IgG4-RD have been reported . HoweverIgG4-RKD should be considered in any renal lesion differential diagnosis, mainly if it exhibits atypical features of malignancies, regardless of age, gender, or ethnicity. Maintaining a high index of suspicion is the key to timely diagnosis and treatment, which can preserve organ function and avoid unnecessary surgery. IgG4-RKD can be associated with renal vein thrombosis and progress to ESKD, mainly if not diagnosed and treated promptly.


Experimental work was carried out to study new fine aggregate shielding construction materials, namely black sand (BS). The BS effect on the mechanical, durability, and shielding characteristics of heavyweight high-performance concrete (HWHPC) was evaluated. This study aimed at improving various HWHPC properties, concertedly. Fifteen mixtures of HWHPC were made, with various variables, including replacing 10% and 15% of the cement with fly ash (FA) and replacing normal sand by BS at various contents . The test specimens were subjected to various exposure conditions, including elevated temperatures, which ranged from 250 °C to 750 °C, for a duration of 3 h; magnesium sulfate (MS) exposure; and gamma-ray exposure. The effects of elevated temperature and sulfate resistance on concrete mass loss were examined. The results revealed that BS is a promising shielding construction material. The BS content is the most important factor influencing concrete compressive strength. Mixes containing 15% BS demonstrated significantly better strength compared to the control mixes. Exposure to 250 °C led to a notable increase in compressive strength. BS showed a significant effect on HWHPC fire resistance properties, especially at 750 °C and a significant linear attenuation coefficient. Using 10% FA with 15% BS was the most effective mixing proportion for improving all HWHPC properties concertedly, especially at greater ages. HighlightsBlack sand is a promising shielding construction material.HWHPC with BS is suitable for NPP construction.BS improved the sulfate and fire resistance of HWHPC, especially at 750 °C.Using a high content of BS had an inverse effect on various HWHPC properties.HWHPC with 15% BS and 10% FA had significantly improved properties.Black sand (BS) is a high economic and strategic value sand, as it contains many economically useful radioactive minerals such as uranium, zircon, hafnium, and thorium, and heavy non-radioactive materials . Although it is used in various industrial applications, such as the nuclear industry or other metallurgical and engineering industries , it has It is a dense mineral, with a specific density greater than 2.85. It can be classified into two main types: dark BS and diluted BS. Dark BS can be found in the western parts, toward the west of Rosetta, Egypt, with various heavy minerals, which when its percentage in sand increases up to 90%, gives it a black color. The diluted BS, which is lighter in color, ‘varies from greyish to yellow’ and can be found in central areas among the Rosetta and Damietta outpourings, and in eastern part toward the east of Damietta . It contVarious radiation-shielding materials are beneficial to avoid the harmful influences of radiation on people and the environment. These materials vary in their efficiency, according to the type of radiation to be absorbed. Heavy materials such as steel, lead, lead glass, polythene, and concrete are appropriate for attenuating radiation ,5. ConcrThe increasing demand for electric power has led to an increase in nuclear power plants (NPPs). The construction of NPPs is subject to many kinds of loading phenomena during their life, from the load of gravity to the load of accidents, such as earthquakes, blast loads, impact loads from tornadoes or projectiles, and thermal stress (from high temperatures). This results from atomic reactions and exposure to various radiation, as well as corrosion of the concrete structure from exposure to salts of sulfates and chlorides. To prohibit the negative impact of these radiations on people and the environment, shielding concrete must be high performance, high strength, and high hardness, with low permeability to air and water. Heavyweight concrete (HWC) is a certain form of concrete that is used to shield NPPs, laboratories, sterilization, radiotherapy rooms for transmission, store radioactive wastes, and hospitals for ionizing radiation shields, due to its low cost, ease of maintenance, environmentally friendliness, durability, satisfactory mechanical properties, and shielding attenuation properties ,7. HWC h3) than NC [To produce HWC with such features, several factors are taken into consideration, such as cost, availability of shielding materials, and radiation type, before selecting appropriate shielding materials. HWA is an essential constituent material in HWC mix design. It contains a large component of material from the metallic stages with high atomic bloc, such as ilmenite, hematite, barite, or magnetite, which function well in enhancing HWC properties, particularly shielding properties ,14. Thes than NC . The radiation shielding characteristics are the essential advantages of HWC materials ,23. NeveNumerous investigations have been conducted to study the impact of various aggregate types on HWC properties, particularly the attenuation properties. It was argued that aggregates containing a high atomic number such as ilmenite, hematite, barite, limonite, lime, magnetite, galena, lead, and steel slag are suitable as anti-radiation materials against gamma rays . Other s3, according to BS EN 206-1 [Many methods are used for producing HWC. First, replacing natural sand, gravel, or both with HWA whose bulk density exceeds 4000 kg/mEN 206-1 . Second,EN 206-1 ,30,31. IEN 206-1 . Fly ash (FA) is a by-product of coal-fired processes and can be used as an SCM for the production of HWC. It is rich in silica and alumina elements , and wheUsing fine materials is another successful method for filling the voids in concrete to improve the properties of HWC. This decreases pore size and porosity. The relationship between radiation and absorbent materials is enhanced by fine materials with a high specific surface area . The filTo the best of the author’s knowledge, no research has been carried out to date on utilizing BS as a novel construction shielding material in concrete. Furthermore, there are no standards or criteria for analyzing the effect of BS on concrete performance. This research presents the first fundamental investigation of the performance of HWHPC made of BS and FA being exposed to elevated temperature, sulfate, and radiation. This research will advance the structural applications of power stations, particularly NPPs.This study investigates the influence of BS on the characteristics of heavyweight high-performance concrete (HWHPC). There were fifteen HWHPC mixes produced, varying in BS, PC, FA, and W/B ratio. NS was substituted by various BS replacement ratios, varying from 0% to 100% to produce HWHPC. Two partially FA replacement proportions of 10% and 15% were used. To ensure that the used W/B was not affected by concrete properties and appropriate for a specific surface that differs with varying BS ratios, several trials were performed in each concrete group, using a flow table slump test. Furthermore, aggregates in the condition of a saturated surface dry (SSD) were used to prevent the effect of aggregate water absorption during mixture, to assess the true effect of the aggregate on the concrete properties. 2/gm surface area. CEM I 42.5 N Portland cement (PC) type according to BS EN 197-1:2011  with a sIn this study, NS was substituted by various BS replacement ratios, varying from 0% to 100%, to produce HWHPC. Fifteen HWHPC mixes were carefully designed, according to absolute volumes. The absolute volume approach is widely accepted and is considered to be more convenient for HWHPC. It was thus used to obtain a denser concrete. To guarantee that the used W/B did not influence HWHPC properties and therefore was suitable for a specific surface with varying BS ratios, the W/B ratio for each mixture was evaluated through flow table slump test trial and error. All HWHPC mixes, thus, had a constant SP to a cement ratio of 1.5%, and the water was used to maintain a flow table slump diameter of 20 ± 2 cm. To examine the influence of the SCMs on the characteristics of concrete comprising BS, two sequences of HWHPC mixes were designed using 10% FA and 15% FA as a proportional addition to PC.3. The mixes were categorized into 3 groups: control, Z, and V. There was no BS in the control group mixtures. X0, Z0, and V0 are control mixtures without FA and with 10% FA and 15% FA, respectively. Groups Z and V comprised 10% and 15% FA, respectively, with BS ratios varying from zero to 100%. 3 of the concrete mix.The used binder had a content of 500 kg/mThe mixing process for HWHPC was identical to that for NC. In a standard mixing process, the materials were blended in the correct sequence: coarse and fine aggregate were briefly mixed dry for 2 min for each mix, accompanied by PC blended with FA. Upon adding 80% of the mixing water, the mixer was turned on. After 1.5 min of mixing, the remaining water was gradually added to the mixer. For a total of 5 min, all batches were mixed.All concrete samples were cast in three layers into 70 mm × 70 mm× 70 mm waterproof wood cubes with compacting of each layer using a vibrating table. The concrete specimens were sealed with a plastic membrane after casting to prevent water evaporation. After de-molding, the specimens were submerged in a water tank until the testing day. As a result, sample curing was carried out in compliance with ASTM C511 . Figure ECP 203-2020 was used to determine the density of the hardened concrete .The compressive strength of concrete was evaluated at 7, 28, 90, and 180 days. The test was carried out on three 70-mm cubes per measure using a 2000 kN testing machine with a loading rate of 0.6 MPa/s. Mass loss, scanning electronic microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and residual compressive strength determination were used to characterize the HWHPC behavior under thermal gradients. To prevent spalling, 15 standard curing aged cubic specimens of 70 mm were dried at 100 °C in a furnace till reaching constant weight and then exposed to one of the temperature gradients  for 3 h. The heating process was performed in a laboratory furnace at room temperature (20 °C) and progressively raised at a rate of 6.7 °C/min until the setpoint temperature was reached. t (%), Mft is the specimen mass (g) under fire exposure temperature (t) at 180 days. Mx0 is the specimen mass (g) with normal water curing at 180 days.After the firing time was completed, the specimens were cooled down for 1 h by opening the furnace door, followed by another 23 h at laboratory room temperature until testing. To distinguish any changes during the test phase, the original mass and compressive strength of the specimens were recorded prior to implementing the elevated temperature. Equation (1) was used to observe the alteration in the block for each sample:4−2) and updating the solution monthly.A series of tests were proposed to determine the HWHPC resistance to magnesium sulfate (MS). The effect of MS on HWHPC samples was continuously monitored at frequent intervals throughout the exposure period, using various tests, such as weight change, residual compressive, and SEM. The procedures involved the ability to immerse three specimens per mix in a water solution comprising 5% MS .t (%), Mst is the specimen mass (g) under MS exposure at time t days. Mx0 is the specimen mass (g) under normal water curing at 90 days.Where Mass Loss is change of mass at time 137Cs), which emits 0.66 MeV photons. The isotope decay rate for 137Cs used in this analysis was 10.0 mCi. Specimens were extracted and were dried in an oven at 105 °C before the examination, as recommended by [Radiation shielding tests were carried out on the specimens of HWHPC, to assess their radiation shielding efficiency using gamma-rays (γ-rays) from Caesium-137 , which is shown as:The half-value layer (HVL) and tenth-value layer (TVL) are absorber thicknesses that decrease the intensity of gamma radiation to a half and tenth, respectively. These can be estimated using the following equations:The mean free path (mfp) is defined as the average distance between two successive photon interactions and is expressed as:3, so they are classified as HWC according to BS EN 206-1 (2013) [The density of hardened concrete in this study was measured and is plotted graphically in 1 (2013) . In geneThe mass loss was due to the evaporation of water more than the decomposition of hydrate in the concrete. It is well known that there are many compositions of water in concrete; including, capillary water, water that is absorbed physically, and water that is bound chemically in CSH and CH . The firAt 250 °C, the first water evaporates and the second water is lost gradually, leading to a great mass loss in the concrete. At 250 °C, the loss of mass in the concrete is due to the hydrates dehydration reaction, and the CH and ettringite (AFt) begin to spoil . Due to This study found the loss of mass increased when the temperature increases accordingly, which indicates the decomposition of the constructional integrity of the concrete. The gradual advancement of the voids in the specimens was also evidence in the case of evaporation. Mixes Z1 and V1 had the greatest strength of the groups. Mix Z1 with 15% BS and 10% FA had compressive strengths of 58, 82, 91, and 98 MPa at 7, 28, 90, and 180 days, which was the highest among the mixes. The average strength advancement in HWHPC systems is based on the pozzolanic activity of FA as the mineral mixture, and the physical and mechanical characteristics of the utilized BS content as fine aggregate, in which the compressive strength has an inverse relationship with the BS content. The compressive strength of HWHPC mixes increases with curing time for all hardened mixes. This is due to increasing the hydration products . Its development is due to its efficiency and the mineral content, which presents an impact on the filler and a pozzolanic response. Consequently, this leads to purring refinement by consumption of the weakened binder of calcium hydroxide (CH), with the composition of a strengthened calcium silicate hydroxide (CSH) binder.3)O8), which evidences the high concentration of Al, as shown in Although the FA content increased in the group V mixture, the compressive strength was lower than the group Z mixtures, which contained the same BS proportion ratio. This is attributed to an increase in the concentration of minerals such as titanium and aluminum from FA and BS in the mixture. Increasing the content of BS over 60% had an inverse effect on the compressive strength, because of generating pores that weakened the concrete microstructure, as in the Z6 microstructure shown in Elevated temperatures are among the most significant risks to buildings and infrastructure. Previous research found that a complex fire resistance phenomenon depends on various parameters, including the aggregate kind, binder form, w/b, explosion temperature, fire time, fiber presence, and the presence of humidity in the concrete ,51,52. TThe results of the maximum compressive strength (MPa) of the HWHPC at various degrees of temperature for a 3 h duration after 28, 90, and 180 days is graphically presented in The BS mixture strength values increased up to 15% BS for group Z at different curing periods, then decreased slightly up to a 60% BS ratio. More than 60%, the BS mixes demonstrated an extraordinary decay in strength at varying ages, particularly at 100%. Under various exposure atmospheres, the compression strength improved more than that of X0.In group V, the BS mixture strength values decreased as the BS ratio increased. At over 60% BS, the BS mixes begin to display extraordinary drops in strength when compared to the control group mixture (V0), at various ages, and particularly at 100%. Under different exposure conditions, the compressive strength increased more than X0, except for V6.The HWHPC mixes presented a significant residual strength gain at elevated temperatures due to appropriate minerals from BS and FA that improved the concrete microstructure. Water vapor being prevented from escaping the concrete pores was due to HWHPC ITZ being strengthened; therefore, the self-curing process began.FS) in the microstructure, as in That is why the strength gained at 250 °C is reflected in the mass loss results. The strength at 500 °C for the BS mixture did not decrease due to the formation of Friedel’s Salt  and C4AF content; chlorides such as NaCl are bound by C3A and C4AF to form FS. The latter is formed either entirely or partly by iron when aluminum is replaced or as a ferrite phase hydration element. Along with the volume expansion of ettringite (Aft), during the formation of hydrate the volume of solid-phase FS expands and is stable [The FS chemical formula is 3CaO·Als stable ,55. In recent decades, there has been a lot of emphasis on concrete sustainability. Following reinforcement corrosion and concrete deterioration, sulfate attack is the second most important durability problem. This causes the concrete to expand, crack, lose strength, and decompose. Sulfate resistance can be influenced by several variables, such as cement type, binder component, and the sulfate cation type and concentration, as well as concrete quality, pH, W/B, and exposure period. Furthermore, MS has the fastest and most efficient influence on concrete. The effects of MS on concrete properties are more serious than those of sodium sulfate .The compressive strength of the HWHPC samples submerged in water and sulfate solutions at 90, 180, and 365 days is shown in 42− with CH to form gypsum that prevents the micro pores and supplies the structure density. It is also due to the composition of the secondary ettringite, because this stage swells greatly, leading to the densification of the hardened mixture.After 90 days of immersion in MS solutions, all mixes showed an increase in compressive strength of 5% to 16.5% and 17% to 42% for groups Z and V, respectively. Until that curing age, an increase in resistance is due to the hydration of the anhydrous cement in the sample. However, it is also due to the response of SOThe FA pozzolanic and BS fineness effects were less porous and more dense compared to X0. In BS concrete, the entry of sulfate ions was slower than in X0.4 and ettringite to the filling of the micro-pores.The initial infusion of sulfate ions contributed by the formation of CaSOThe initial increase in concrete compressive strength of groups Z and V after 90 days of sulfate attack can be attributed to the following:Due to previously stated reasons, the microstructure becomes thicker and denser and thereby increases the compressive strength of the BS mixtures. The decrease in the compressive strength of the control mixture in the MS solution after 90 days was because of the detachment of material and cracking. This is due to the expansive impact of the sulfate attacks. The composition of sulfate-based products, such as secondary ettringite, resulted in swelling. This caused micro-cracks and the devastation of the material. The realization of this stage in the small pores is accepted as the driving power for the expansion produced in the Portland cement samples, as in The strength at 365 days decreased by the range of 9–14% and 3–10% for groups Z and V, respectively, compared to the same reference mixture under normal conditions. This may be attributed to the dilution effect, which reduced the CH. In addition, exhausted by the pozzolanic reaction, the sulfate and magnesium ions reacted with CSH, leading to a magnesium silicate hydrate (MSH) with no cohesion. Ettringite is formed when sulfate reacts with CAH. It is an unstable compound that grows in size. As a result, the microstructure of the concrete began to crack.The composition of gypsum results in a soft concrete surface that causes the loss of mass and strength, but secondary ettringite takes a greater volume than the foremost reactants, leading to expansion and concrete cracking. The resulting cracking allowed the transportation of sulfate ions into the concrete that speeded up the degradation of HWHPCs.The results are attributed to the influence of FA pozzolanic, which is considered the most effective way of reducing the worsening influence of sulfate attack, as well as FS formation. The pozzolanic materials strengthen the concrete microstructure due to their particle size and can alter the chemical composition and hydration reactions, in particular the FA. With FA the, sulfate resistance, particularly MS, can be significantly increased.137Cs. 137Cs sources. The results indicated that Z1 with 15% BS is remarkably effective for shielding gamma rays. The attenuation values of BS concrete are more than those included in NS. It is clearly seen that the linear attenuation coefficient depends on the BS content used.The linear attenuation coefficient (μ), half-value layer (HVL), tenth-value layer (TVL), and mean free path (mfp) of concrete mixes made with BS fine aggregate was estimated at a photon energy of 0.662 MeV for 137Cs increases. The lower the value of the HVL and TVL, the better the radiation shielding materials are at increasing the BS ratio. Nevertheless, the HVL and TVL values for HWHPC mixes incorporating BS fine aggregate were less than the Z0 incorporating LS. The results also revealed that the values of HVL and TVL were directly related to the BS concrete density, so Z1 had lower HVL and TVL values than Z6.The HVL or TVL of a substance is utilized to denote the efficacy of gamma-ray shielding. HVL is the thickness at which an absorber reduces radiation to half its original intensity, while TVL is the thickness where an absorber decreases the radiation to one-tenth of its original intensity . The HVLr) was calculated using Microsoft Excel’s “Pearson” function [Under the same various exposure conditions, the association between mass loss and compressive strength is shown in this section for group Z mixtures. The correlation coefficient . An r = 1 indicates that the correlation is fully linear; r = −1 indicates that the correlation is inversely linear; and r = 0 indicates that the pairs of values are fully independent. The degree of correlated closeness is then classified as medium if 0.3 < r < 0.5; significant if 0.5 < r < 0.7; high if 0.7 < r < 0.9; and extremely high if 0.9 < r. A high correlation indicates a significant association between two or more variables, whereas a low correlation indicates that the variables are hardly related. The estimated The statistical group included seven values that represented the input data used to compute the correlation coefficients, as illustrated in BS is a promising concrete shielding material that is rich in a specific mineral that improves HWHPC properties concertedly, particularly elevated temperature resistance.Using BS increased the average density of HWHPC by 23% more than the control mixture, X0.Using 15% BS with 10% FA (Z1) is the optimum ratio that improves all HWHPC properties.The mass loss of Z1 was recorded as −4%, −5.1%, and −6.3%, compared to −7.3%, −11.2%, and −18.5% for X0 at 250 °C, 500 °C, and 750 °C exposure conditions.The mass loss of Z1 recorded +1.5%, −2.5%, and −4%, compared to +1.1%,−9%, and −12% for X0 at 90, 180, and 365 days with sulfate exposure conditions.The compressive strength under normal, 250 °C, 500 °C, and 750 °C exposure conditions of Z1 was 132%, 134%, 135%, and 181% higher than X0, and 106%, 108%, 106%, and 105% higher than Z0 at 180 days.The compressive strength under sulfate exposure conditions of Z1 was 139%, 178%, and 206% higher than X0 at 90, 180, and 365 days.Z1 showed significant shieling attenuation results, despite not using HWA as a coarse aggregate.In this paper, the effect of new fine aggregate shielding construction materials, namely black sand (BS), on HWHPC mechanical, shielding, and durability properties were studied. The following conclusions were drawn from the obtained results:Study group Z durability properties, especially fire resistance at temperatures over 750 °C.Study the effects of using HWA such as serpentine, magnetite, and iron slag with greyish-yellow BS on HWHPC shielding attenuation properties, especially at elevated temperatures.Future studies should focus on the following subjects:


Antibiotic resistance raises ethical issues due to the severe and inequitably distributed consequences caused by individual actions and policies.Synthesis of ethical, scientific and clinical literature.Ethical analyses have focused on the moral responsibilities of patients to complete antibiotic courses, resistance as a tragedy of the commons and attempts to limit use through antibiotic stewardship.Each of these analyses has significant limitations and can result in self-defeating or overly narrow implications for policy.More complex analyses focus on ethical implications of ubiquitous asymptomatic carriage of resistant bacteria, non-linear outcomes within and between patients over time and global variation in resistant disease burdens.Neglected topics include the harms of antibiotic use, including off-target effects on the human microbiome, and the lack of evidence guiding most antibiotic prescription decisions. It is widely acknowledged that the development of resistance by human bacterial pathogens to pharmaceutical antimicrobials due to their use (acquired antibiotic resistance or acquired ABR) poses a major threat to global public health. Recent data suggest that over 1 million deaths per year are attributable to resistant bacterial infectionsMuch of this disease burden is concentrated in low- and middle-income countries (LMICs) where surveillance for resistance is often incomplete.,Acquired ABR is an important topic for ethical analysis since the consequences for human health and well-being are often severe , the harms of resistant infection are often inequitably distributed and human actions are major contributors to the problem.In this article we review key concepts, scientific data and ethical issues relevant to clinically significant acquired ABR in common bacterial infections in humans, outlining the advantages and limitations of common conceptual and policy approaches to ABR. In light of these analyses, we discuss appropriate antibiotic use policies in humans, public health interventions among asymptomatic carriers of resistant bacteria and public health priorities in different global settings. We conclude by identifying avenues for future research and policy development related to acquired ABR, noting previous work on ethical issues related to some other types of non-bacterial antimicrobial resistance , fairness  and freedom (or liberty).Bacteria with the potential to cause disease in humans are ubiquitous: in the human microbiome that contains more bacterial organisms than cells of the host organism,The use of antibiotics necessarily exposes this microbial ecosystem to variable concentrations (at different niches within the body) of compounds that are variably lethal to different bacterial species (or subpopulations within a species). After exposure, pathogens can acquire additional resistance through selection for resistant mutants, activation of latent resistance mechanisms or acquisition of mobile resistance determinants from other species,Although the magnitude of the benefit of living in the antibiotic era is hard to under-estimate,Concerns about acquired ABR arose very early in the antibiotic era. Alexander Fleming provided an early formulation of the problem in 1945, when he claimed that: ‘the greatest possibility of evil…is the use of too-small doses [of penicillin], so that, instead of clearing up the infection, the microbes are educated to resist penicillin and a host of [resistant] organisms is bred out which can be passed on to other individuals and perhaps from there to others until they reach someone who gets a septicemia or a pneumonia which penicillin cannot save. In such a case the thoughtless person playing with penicillin treatment is morally responsible for the death of the man who finally succumbs to infection with the penicillin-resistant organism’.This compelling description of origin of acquired ABR through ‘inadequate’ treatment of an ‘eradicable’ pathogen that is ‘unavoidably’ transmitted directly between neighbouring individuals has been widely influential in discussions of acquired ABR ever since . It may be tempting to think that patients failing to finish the course is one of the most important ethical issues related to ABR. Indeed, the specious simplicity of Fleming’s parable allows a line of moral culpability to be drawn directly from the original negligent prescriber (or non-adherent patient) to the victim denied effective antibiotic therapy. The obvious solutions are maximalist and technical: larger doses, longer courses of therapy and perhaps a broader spectrum agent to ensure all potential pathogens are ‘covered’, followed by the development of new antibiotic drugs  when old ones fail.Neisseria gonorrhoeae and cephalosporins,in vitro monocultures,in vitro modelsWhile it is true that under-dosing of (or otherwise inappropriate) antibiotic therapy can result in acquired ABR in the infecting pathogen  understand the resource at stake ,,On the other hand, antibiotic resistance is disanalogous with standard commons tragedies in multiple ways. First, an increase in an individual’s consumption of antibiotics does not result in progressively greater benefits. Although antibiotics may be highly beneficial in the context of active infection, they offer little if any benefit to healthy individuals, and prophylactic or immunomodulatory use in those with underlying conditions is helpful only in a very narrow set of circumstances. The maximal expected benefit of any antibiotic treatment occurs when therapy is targeted against a definitively diagnosed infection, but multiple uncertainties erode this benefit in real-world situations. These include (i) diagnostic uncertainty, as the cause of a patient’s illness may not be due to bacterial infectionClostridioides difficile) and other dysbiosis-related risks such as an increased incidence of inflammatory bowel diseaseSecond, in contrast to these diminishing benefits, antibiotic therapy is accompanied by a reasonably fixed range of adverse effects. As well as acquired ABR, these include allergic reactions, organ toxicities, superinfections  as well as regulation of antibiotic consumption. However, as we describe in the next sections, the governance of antibiotic use through idealized prescription guidelines and other stewardship interventions faces multiple real-world challenges arising from the many agents and interests involved in practice.both the patient and the wider community, which the ‘commons’ formulation necessarily places in opposition. When attempting to resolve this assumed conflict, and in concordance with dominant professional norms, clinicians often prioritize their immediate patient over the interests of other, distant and/or future patients.,,,Another significant departure from the standard ‘commons’ formulation is the fact that, in most healthcare systems, patients do not have unmediated access to antibiotics. When the central role of the prescriber is added to the (assumed) collective action challenge of the tragedy of the commons, the result is a ‘dual agent’ problem first recognized in medical economic analyses.,Although inescapable within the ‘commons’ formulation, this conflict of interest can disappear when the limitations of this formulation are considered. The most straightforward case is where antibiotic therapy offers no benefit at all (antibiotic abuse),,,It is thus a common situation that an antibiotic prescription is in the interest of neither the patient nor the wider community. This is a tragedy, but its structure is not that of the tragedy of the commons . The frequency of this problem seems to argue against random incompetence among prescribers and suggests the need for an expansion of the tally of the risk and benefits of these decisions to include the prescriber. Under this expansion, which can be labelled a ‘dual agent-principal’ problem, the prescriber can now be understood to be acting for the patient, the community and, also, ‘themselves’. Moral hazard arises when prescribers’ incentives do not align with those of the other two parties, and qualitative research has identified these adverse drivers of antibiotic prescribing as active in multiple medical contexts.One potential response to the problems created by the conflicts of interest above is the appointment of ‘antibiotic stewards’—neutral professionals set apart from individual prescribers and their patients whose primary role is to steward the scarce resource of effective microbials by tipping the balance of average antibiotic use away from common instances of conflicted and profligate depletion. Yet this in turn raises the ancient dilemma, to paraphrase Plato: who will steward the stewards?Agent-level conflicts affect those involved in stewardship teams.,Moreover, stewardship resources are often concentrated in hospitals, where some of the more overt harms from resistant bacterial infections often manifest, but it is in the general community that the majority of antibiotic consumption occurs  carriers of resistant organisms. The recent COVID-19 pandemic has highlighted the ethical salience of public health measures for asymptomatic infection, which sometimes involve infringements upon carriers’ freedoms and well-being in the name of reducing public health risks. Unlike infections with respiratory viruses that last days or weeks, resistant bacteria are often carried asymptomatically for years, meaning that cumulative infringements on carriers’ lives may be even more significant. Being identified as a carrier can result in restricted access to healthcare and mental health issues due to stigmatization,Much of the debate about antibiotic resistance focuses on ethically difficult trade-offs arising from antibiotic use, but these situations represent a tiny fraction of the global disease burden due to resistant bacteria. It has been noted that there is a stark difference between problems of ‘excess’ and those of ‘access’.Above and beyond altruistic motivations for high-income countries to help address these social determinants in poor communities, there are also self-interested reasons: since resistant bacteria now travel easily from one community to another, and since containing an outbreak of highly resistant bacteria in high-income countries can exact a high toll in disease burden and economic costs, it is arguably in the self-interest of high-income countries to address the structural causes of global health injustice that contribute to the emergence, persistence, and spread of resistant bacteria.The apparently deflationary conclusion that much of the framing of resistance policy has been oversimplified and/or misguided nevertheless opens the door to more innovative approaches in ethics, science and health policy. From an ethical perspective, policy and clinical decisions should be based on value judgements informed by sound evidence. Where this evidence is lacking there is an ethical imperative for more relevant scientific research and public health surveillance. Policy should also focus on harm reduction, and this in turn requires measuring harm.,Clinical science should therefore focus on producing evidence regarding (i) optimal antibiotic durations for common bacterial infections or criteria for antibiotic cessation (since most standard ‘courses’ of antibiotics appear excessive); (ii) the minimally effective antibiotic spectrum for specific types of infections, noting that the current paradigm of antimicrobial resistance testing may encourage unnecessary bystander selectionThere is also a need for communities to define  locally acceptable antibiotic treatment thresholds, or the conditions under which not prescribing antibiotics of minor or marginal benefit would be socially acceptable. The resulting socially endorsed prescription policies would need to be updated as the local prevalence of resistance changes over time, and this in turn requires responsive public health surveillance systems that can feed back resistance data to policymakers and prescribers in a timely manner.Ethics research might therefore focus on improving community engagement strategies, including how best to inform the public regarding the harms of antibiotic therapy, which appears to be an effective intervention to reduce consumption.Antibiotic resistance and the use of antibiotics raise a range of ethical issues that have recently received more sustained analysis in the bioethics literature. Standard conceptual frameworks such as those related to patients’ moral responsibilities to comply with prescriptions, tragedies of the commons or stewardship have significant limitations and may distract from larger issues including the inequitable global distribution of resistant bacterial disease and access to antibiotics. Ethical analyses of public health control measures for antibiotic resistance should involve not only risk–benefit assessment but also consideration of how other ethical values such as fairness and liberty might be undermined or promoted. Strategies to improve the effectiveness of antimicrobial treatment, including through avoiding acquired ABR, must be based on a solid ethical and empirical foundation.The authors have no potential conflicts of interest.No new data were generated or analysed in support of this review.EJ is supported by Wellcome Trust (UK) [203132 and 221719].


Fibre-reinforced polymers (FRPs) are a promising corrosion-resistant alternative to steel reinforcement. FRPs are, however, generally costly and have a high energy demand during production. The question arises whether the high performance of FRPs and possible savings in concrete mass can counterbalance initial costs and environmental impact. In this paper, a parametric design study that considers a broad range of concrete infrastructure, namely a rail platform barrier, a retaining wall and a bridge, is conducted to assess the mass-related global warming potential and material costs. Design equations are parametrised to derive optimum reinforced concrete cross-sectional designs that fulfil the stated requirements for the serviceability limit state and ultimate limit state. Conventional steel reinforcement, glass and carbon FRP reinforcement options are evaluated. It is observed that the cross-sectional design has a significant influence on the environmental impact and cost, with local extrema for both categories determinable when the respective values become a minimum. When comparing the cradle-to-gate impact of the different materials, the fibre-reinforced polymer-reinforced structures are found to provide roughly equivalent or, in some cases, slightly more sustainable solutions than steel-reinforced structures in terms of the global warming potential, but the material costs are higher. In general, the size of the structure determines the cost competitiveness and sustainability of the FRP-reinforced concrete options with the rail platform barrier application showing the greatest potential. A large part of existing infrastructure is built out of reinforced concrete. To protect the internal steel reinforcement from corrosion, a suitable concrete cover 20–60 mm) is required. A loss of passivation to the steel over time due to progressive carbonation of the concrete or the ingress of chlorides can lead to the corrosion of the reinforcement and the deterioration of the structure . A possi0–60 mm iThe first investigations regarding the implementation of FRPs in structural concrete took place in the 1960s ,6,7,8,9.A longer service life is anticipated due to the corrosion resistance of FRPs, which also lowers future maintenance costs. Corrosion-related damages are the main cost drivers for steel-reinforced concrete infrastructure ,23,24,25Structures subjected to harsh environments are therefore likely to benefit most from the application of FRP reinforcement. Such structures include see : (i) strAs stated before, FRPs are usually quoted as being expensive based solely on the initial cost of the product. More holistic investigations that consider potential material savings and the overall environmental footprint should take into account various parameters such as the structure size. However, to date, such investigations are rarely reported in the literature. This paper seeks to identify application areas with the greatest potential for realising the benefits of FRP reinforcement. A parametric design study is undertaken where the concrete mass and weight of the main longitudinal reinforcement are linked to characteristic values of global warming potential (GWP) and costs. The investigation covers a broad range of structures that are representative of small (rail platform barrier) to medium  and large (bridge) structures exposed to harsh environments. The costs and GWP of the concrete and steel or FRP reinforcement  over stages A1–A3  of an LCA analysis are compared. The results serve as the foundation for an evaluation of not only the types of structures that could benefit most from FRP reinforcement alternatives but also structures whereby FRPs may not be currently competitive on the basis of the A1–A3 cost or environmental metrics. ftk,100 is calculated according to ACI 440.1R-15 [CE) and temperature aspects (factor CT), see Equation (1). In the case of GFRP, which is not as resistant as carbon, more onerous reduction factors would apply.In addition to ordinary steel reinforcement, this study investigates FRP reinforcement with different fibre materials, namely carbon (CFRP) and glass (GFRP) in the form of bars (GFRP and CFRP) or textiles (only CFRP). Other materials such as basalt (BFRP) are also suitable, but concerns about the durability of basalt in the alkalinity of the concrete remain ,37. Alth40.1R-15  considerftd is calculated as the long-term strength ftk,100 divided by the material safety coefficient γm. For FRP rod reinforcement, the safety coefficient was taken as 1.5, whereas for textile reinforcement, a smaller value of 1.3 was used in accordance with recent investigations [The design strength igations . The bonigations ,41. The fyk of 550 MPa and Young’s modulus of Es = 200 GPa. In terms of the concrete, different strength classes ranging from C20/25 to C50/60 are considered in this study. All the necessary input material properties for the steel and concrete are taken from EN 1992-1-1 [φ = 2.0. To reflect a harsh environment, the exposure class is taken to be higher than XC2, meaning that the allowable crack width for steel reinforcement is limited to 0.3 mm under quasi-permanent loads, while it is 0.5 mm for the FRP-reinforced variants in accordance with ACI 440.1R-15 [bc for bond in dependency of the reinforcement diameter cb = 2 · Ør was taken. For the steel reinforcement, additional durability criteria according to EN 1992-1-1 [ρ is consistently taken as 2.4 t/m³, while the concrete material safety coefficient is γm = 1.5.The selected B550B steel reinforcement is commonly used in Austria with a characteristic yield strength 1992-1-1  and are 40.1R-15 . Differe1992-1-1  has to bThe design of structures is governed by various requirements in the serviceability limit state (SLS) and ultimate limit state (ULS). The following requirements are considered in the current work: (a) flexural capacity, (b) deflection control, (c) crack-width control and (d) stress limitation. In the parametric comparisons, the main longitudinal reinforcement requirements are calculated but any shear reinforcement is not taken into account. The structures examined, however, are not shear sensitive. In recent decades, various guidelines and frameworks have been developed for the design, dimensioning and testing of FRP structures  the concrete to avoid longitudinal cracking of the concrete (factor k1 in EN 1992-1-1) and nonlinear creep effects (factor k2 in EN 1992-1-1) and (b) the reinforcement, where the steel reinforcement stress is limited to avoid yielding and excessive crack opening (factor k3 in EN 1992-1-1), while in FRP reinforcement, the reinforcement stresses are limited to avoid creep rupture  and ULS  are fulfilled [The provisions in n curves  using a ulfilled . The feaAf and d combination along the optimum curve by the environmental impact per m³ or kg, respectively. The values per mass based on a cradle-to-gate life cycle assessment were extracted from the literature [It is possible to obtain a direct link between the structure’s environmental impact in terms of the global warming potential (GWP) and the presented optimum design functions by multiplying the reinforcement and concrete masses of each terature  and are terature ) with a terature , GWP of Furthermore, the optimised design functions can also be linked to economic data. The costs per m³ or per kg, respectively, are presented in The mass-related connections to economic or environmental aspects enable a comparison of the efficiency of structures reinforced with different types of reinforcement. This is performed in the following for both the economic as well as the environmental impact in terms of the GWP. An overall efficiency that reflects both cost and environmental aspects can be assessed, but weighting factors must be defined for each impact category. These factors can differ for various projects. It is also expected that environmental impact categories will become more important in the future, whereas in current practice, the cost is often the dominant decision criterion. Hence, for the sake of clarity, both impact categories are studied individually in this paper. The assessment at this stage of the investigations is based solely on the material masses. Other impacts that arise, for example, from the formwork, are considered to be the same for all reinforcement products and are therefore omitted in the results in Small-size structures in concrete infrastructure are common and varied. These include components without major requirements in the SLS and ULS, such as cable trenches. In this study, L-shaped rail platform barriers are investigated. The walls of such structures typically have a length of 0.95 m in Austria, according to general design provisions of the Austrian Railway operators (ÖBB). Usually, a concrete class C25/30 is used. The barrier is loaded by earth pressure due to the backfilling, and additional loadings arise from crowds on the platform and a service car for maintaining the platform. The exact loading conditions are provided in The results of the parametric study are depicted in When the material mass of the solutions that bound the optimum design curves is linked to the GWP and the costs (green and orange dotted line in 2 eq/m), both the CFRP  and GFRP  options provide somewhat more sustainable solutions. However, the opposite trend is apparent for the costs, with the RC structure (15.3 EUR/m) exhibiting the lowest costs when compared to the CFRP-  and GFRP-reinforced  structures.Based on the mass-related GWP calculations, it is observed that when compared to steel reinforcement  and GFRP-reinforced  structures exhibiting almost the same GWP, while the CFRP-reinforced structure  has a slightly higher GWP. In terms of the economics, the higher costs that were observed for the FRP-reinforced rail platform barrier are even more apparent for the retaining wall, with the steel-reinforced structure showing a mass-related cost of 295.2 EUR/m, which is significantly lower than the GFRP-  and the CFRP-reinforced  comparators.In terms of the GWP, the relative advantage of the FRP reinforcement observed in the small size example is no longer apparent, with the steel- (569.0 kg COA slab bridge is investigated as being representative of a large-span structure. The bridge span has an effective length of 15 m and is fixed to the bridge abutment (as in a frame bridge), causing a hogging moment that is almost equal to the sagging moment in the midspan of the bridge. This allows an estimate of the overall longitudinal reinforcement required, even though only the cross section at midspan is investigated in this study. The loading consists of the dead load, earth pressure behind the abutment and live loads due to traffic. Other loadings such as temperature or wind are neglected for this example. The exact dimensions and loading conditions can be found in The results of the parametric design are depicted in 2 eq/m) showing almost the same mass-related GWP as the GFRP-reinforced structure  and the CFRP structure being slightly higher . In terms of the mass-related costs, the steel-reinforced structure’s costs (1251.6 EUR/m) are significantly lower than the GFRP  and CFRP  ones. It is noticeable in When comparing the mass-related GWP for the reinforcement options, similar trends to those in the medium-size structure are evident, with the steel-reinforced structure  but also the fibre material (carbon or glass) plays a significant role when determining the GWP and costs of a reinforced structure. The cost of the reinforcement, however, is subject to current and future developments. Considering the recent volatility in the market (2022) due to global crises, the price of steel has increased up to threefold. This sharp increase has not yet been observed for FRP reinforcement where, according to suppliers, the price increase has been about 10–12%. Considering this aspect and the results in fck = 20 and 50 MPa, to investigate whether a different concrete strength would lead to a better material utilisation and hence lower costs and environmental impact. The results are shown in fck = 20 MPa for each variant).It was noticeable, especially in the case of the FRP-reinforced structures, that the material masses were driven by the concrete compressive strength, either by the ULS flexural capacity or by the limitation on the SLS concrete stresses. In this section, the GWP and costs are derived for all three structures using a compressive strength that varied between In all cases, a decreasing material mass of the concrete could be observed, usually accompanied by a partial increase in reinforcement mass. A general conclusion, however, on the mass-related GWP and costs cannot be made, but rather, a clear trend for the individual structures and the material mass could be observed. While for smaller-sized structures, an increase in concrete compressive strength leads to a rise in mass-related GWP and costs; this trend progressively shifts for medium and large structures. For the smaller-sized structures, the material savings in concrete mass due to the higher concrete strength therefore do not compensate for the additional reinforcement needed. When comparing the steel- and FRP-reinforced structures, the decrease in mass is more distinct for the FRP-reinforced design than for the steel-reinforced one, leading to a bigger spread between the mass-related GWPs. The higher costs of the FRP reinforcement, however, often counterbalance the decrease in material mass, leading only in the case of larger-size structures to a less expensive structure with increasing compressive strength.A main advantage of FRP reinforcement is its high resistance against corrosion. Because an alkaline environment is not required to protect the reinforcement from rusting, the concrete mix design can be optimised by reducing the clinker amount while simultaneously providing the same performance. Recent studies introduced mixes with up to 40% less cement clinker . In the FRP reinforcement is still at a relatively early stage of development and applications are not widespread. It is often argued that with increasing demand for the reinforcement and increasing competition in the market, the price of FRP reinforcement will decrease. In this section, a decrease in costs of 30% is simulated and the effects on the total costs of the structure are compared, see It can be seen that, especially for the carbon-reinforced structures, a 30% decrease in the FRP reinforcement costs leads to a progressively larger decrease in the overall costs with increasing structure size. Interestingly, the costs of the concrete also decrease, meaning that the local minimum in the optimum design curve shifts towards a structure with a greater reinforcement area but a smaller depth of the structure. In all cases, however, the material costs of the FRP-reinforced structures are still greater than the steel-reinforced ones.Immediate action that can be undertaken to lower the cost of the structure is to build hybrid-reinforced structures, e.g., to use FRP reinforcement only where the reinforcement is prone to corrosion. This is demonstrated in the following for the retaining wall example, where, due to pressurised water, the main reinforcement layer that was calculated in The optimum design curves for rectangular FRP-reinforced structures under flexural loading are generally driven by SLS requirements rather than the ULS flexural capacity. An optimised balance between concrete and FRP strength, which differs for the various structures under consideration, allows for higher overall utilisation rates.For the CFRP-reinforced structures, distinct local minima for cost or GWP exist, meaning that an optimised cross-sectional design has a decisive influence on both parameters. For the cases considered here, it was generally found to be favourable to have a larger concrete cross-sectional area and smaller CFRP reinforcement area. However, this would lead to a heavier structure.For the GFRP-reinforced structures, due to the lower environmental impact of the reinforcement, a smaller concrete cross-sectional area and larger reinforcement area was generally found to be more favourable in terms of the overall GWP of the structure.It is observed that FRP-reinforced structures are competitive with steel-reinforced options in terms of the GWP where, in particular, the GFRP-reinforced structures exhibit relatively low mass-related GWP. This trend is amplified if greater cement reductions in the concrete mixes can be realised due to the high corrosion resistance of FRP reinforcement.In terms of the mass-related costs, FRP-reinforced structures remain more expensive than steel-reinforced variants. This was still the case even when a potential price reduction of up to 30% due to mass production was simulated.In this paper, design curves for FRP-reinforced concrete structures under flexural conditions, that fulfil all stated requirements in the ULS  and SLS  were derived using parametric design studies. Subsequently, the mass-related GWP and material costs of different infrastructure buildings were studied. The influence of various parameters such as the size of the structure and concrete compressive strength on the environmental impact and economics was investigated. This allows for an evaluation of the potential for different types of FRP reinforcement in selected concrete infrastructure applications. The following general conclusions can be drawn:The smaller the structure, the smaller the difference in the material costs and GWP compared to steel structures. This observation can be traced back to the concrete cover having a more significant impact on the overall concrete volume in smaller structures. Hence, a reduction in the concrete cover due to the high corrosion resistance of the FRP reinforcement significantly reduces the GWP and costs of the overall structure. It is therefore more advantageous when the FRP textile reinforcement, which has a smaller reinforcement area and thus allows for a smaller wall thickness, is used in small structures. This type of reinforcement can also be more cost-efficient relative to FRP bars.Hybrid structures where only the reinforcement prone to corrosion is replaced by FRP reinforcement could suit medium-sized structures like the investigated retaining wall. A hybrid approach would lower the construction costs, while a structure with a lower GWP can still be achieved.Large-size FRP-reinforced structures such as bridges show significantly higher costs. This comparison was based on solid, reinforced cross sections and demonstrates that a simple replacement of steel reinforcement with FRP reinforcement, particularly CFRP, is not a suitable solution. Instead, a different design concept with more optimised, prestressed cross sections would take advantage of specific FRP reinforcement characteristics, such as the lower elongation stiffness, and thus better utilise the high-performance FRP reinforcement.When assessing potential application areas for FRP reinforcement, the size of the structure plays a significant role, as follows:Using cost and energy demand due to production as the sole decision criterium does not capture other factors that are important when choosing the preferred design. The possible longer service life of an FRP-reinforced structure, combined with lower maintenance costs and higher material utilisation, would lead to economic and socio-political advantages. It is also noted that only rectangular cross sections were considered in this study. The potential for further optimisation exists, e.g., through cross-sectional or topology optimisation.


Convolutional neural network (CNN) is a deep-learning method for image classification and recognition based on a multi-layer NN. In this study, CNN was used to accurately assess cavernous sinus invasion (CSI) in pituitary adenoma (PA).n = 102) and non-invasive groups (n = 269) based on surgically confirmed CSI. Images were selected on the T1-enhanced imaging on MR scans. The cohort underwent a fivefold division of randomized datasets for cross-validation. Then, a tenfold augmented dataset  of the training set was enrolled in the pre-trained Resnet50 model for transfer learning. The testing set was imported into the trained model for evaluation. Gradient-weighted class activation mapping (Grad-CAM) was used to obtain the occlusion map. The diagnostic values were compared with different dichotomizations of the Knosp grading system .A total of 371 patients with PA were enrolled in the retrospective study. The cohort was divided into the invasive  of Knosp grade for CSI prediction was 0.84; the cutoff was 2.5 with a Youden value of 0.62. The accuracies of the CNN model ranged from 0.80 to 0.96, with AUC-ROC values ranging from 0.89 to 0.98. The Grad-CAM saliency maps confirmed that the region of interest of the model was around the sellar region.We constructed a CNN model with a high proficiency at CSI diagnosis. A more accurate CSI identification was achieved with the constructed CNN than the Knosp grading system. Pituitary adenomas (PAs) are common intracranial tumors. Although considered benign, 25%–55% of PAs present invasive behavior, characterized by the invasion of adjacent structures, including sphenoid sinus, diaphragm sellae, and cavernous sinus (CS) . CavernoConsidering the close relationship of ICAs, the histological specimens of the medial wall of CS are not routinely available. Intraoperative observations are still the gold standard for CSI. Currently, the application of endoscopes in transsphenoidal surgery enables the surgeon to inspect the medial wall of CS directly and clearly and thus make a reliable judgment about CSI. Pre-operative prediction relies on the Knosp grading system. In 1993, the classification was proposed to quantify the CSI pre-operatively . HoweverConsequently, a method that can accurately predict CSI and reduce observer bias is highly required. Deep learning is an essential branch of machine learning (ML) and has improved image recognition and classification –14. MachAll data were obtained from patients with PA who underwent transsphenoidal surgery between 2016 and 2020 at two centers, namely, the Fuzhou General Hospital and Peking Union Medical College Hospital. The review boards of the two medical centers approved this study. The requirement for informed consent was waived because of the retrospective nature of the study.Patients with clear T1-enhanced imaging suitable for analysis, a surgical record of CSI, and a pathological diagnosis of PA were included. Cases with other intracranial tumors, a previous history of surgery or trauma in the sellar region, and artifacts were excluded.The Knosp grading system was assessed on the coronal magnetic resonance imaging (MRI) scans. Three lines that connect the cross-section of the intracavernous and supracavernous ICAs  distinguish four grades of parasellar adenoma extension. Grade 3 could be subclassified because the tumors extended into the superior CS compartment (3A) or inferior CS compartment (3B). Intracavernous ICAs completely encased by a tumor are defined as grade 4 . An expeCSI was diagnosed based on surgical evidence. If the medical wall of CS is vague, and CS structures are visible, or an invasion was directly visible, CSI is confirmed. If the medial wall is smooth and intact after resection, CSI is considered to be absent. A total of 102 patients were classified into the invasive group, and 269 patients were included in the non-invasive group.All imaging data were extracted on the coronal T1 contrast-enhanced scans. Images were evaluated by two senior neurosurgeons with over 10 years of experience in the PA diagnosis and management of performed CSI radiological evaluation. Only one image that was evaluated with potential CSI was enrolled in a case with surgically confirmed CSI. Images with the maximum area of the tumor were selected in PAs without CSI. In the cohort, 371 images were subjected to a fivefold division of the randomized dataset for cross-validation.The principal investigator from each center assessed and collected images separately. Patient information was filtered and eliminated, and only the acquired images were retained. Finally, the adjudicator screened these images for proofreading and adjudicating to reduce observer bias. The acquisition process is illustrated in The image pre-processing procedure is summarized as follows: 1) all images were converted into 256 × 256 square images by using zero padding and image resizing as appropriate, and 2) augmentation procedure was carried out by using the horizontal flip and rotation (within 90°) in the training and validation sets. The augmented dataset was obtained for model training .Convolutional neural networks (CNNs) are among the deep learning models used to recognize and classify images, and they are characterized by multiple layers of feature maps, including convolution  and pooling  . At the The model framework was constructed, and fine-tuning was performed using the pre-trained Resnet50 model. Resnet was proposed in 2015; it is a CNN with a 50-layer network structure consisting of a series of residual modules, and it essentially solves the problem in which multi-layer network models lead to vanishing or exploding gradients, which is conducive to the convergence of network models . The Resp < 0.05.SPSS (version 25) was used for statistical analysis. Categorical variables were expressed as numbers (percentages) and analyzed using the chi-square test. Statistical significance was considered at Confusion matrices were constructed according to intra-operative diagnosis and pre-operative prediction. The contingency tables of the Knosp grading system were constructed using three dichotomizations . True positives, true negatives, false positives, and false negatives were recorded. The diagnostic index included sensitivity, specificity, a positive likelihood ratio (+LR), a negative likelihood ratio (-LR), precision, and predictive accuracy. The summary of diagnostic odds ratio (DOR), F-score, and area under the receiver operating characteristic (AUC-ROC) were used as the composite index to evaluate the diagnostic performance. DOR is the ratio of +LR to -LR. F-score is the harmonic mean of precision and recall. Gradient-weighted class activation mapping (Grad-CAM) was used to identify the features deduced with the convolutional filter application.https://pytorch.org) and operated in JupterNotebook .All imaging data-processing and model methods were implemented using Pytorch . By comparison, the reliability for the middle grades was weak.The cohort of 371 patients included 212 males and 159 females with a mean age of 55.52 ± 11.71 years. A total of 102 (27.5%) patients were surgically confirmed with CSI, and 269 (72.5%) patients were surgically confirmed without CSI  and high (4) grades.The predictive capabilities of the CNN model were presented after fivefold cross-validation, as shown in The sensitivity and specificity of the optimal model were 0.95 and 0.96, respectively. The DOR (16.61–503.50) and F-score (0.69–0.93) of the deep learning model were higher than those of the dichotomizations of the Knosp grading system . The AUC-ROC value of the model (0.89–0.98) was higher than that of the Knosp grading system. Therefore, the CNN model has higher diagnostic reliability than the Knosp grading system. Grad-CAM saliency maps showed that CSI prediction was made by the attention to the large area around the sellar region, unanimous with the contributing areas in tumor location.Radiological characteristics are essential for the pre-operative prediction in CSI. Currently, the pre-operative diagnosis of CSI is mainly based on Knosp grading and modified Knosp grading. In the studied cohort, Knosp grades 0–1 and 4 have high accuracy in recognizing positive CSI. The low and high Knosp grades can effectively facilitate CSI evaluation. However, intermediate grades (grades 2–3) presented weak reliability, especially grades 2–3A . PAs in ML enables the use of existing imaging facilities and common sequences to capture information per pixel through computer algorithms and accurately classify diseases, thus reducing the hardware and time costs required to optimize image quality. Deep learning models have been applied for the examination of intracranial tumor in processes such as the diagnosis and classification of PAs –21. The Our study describes a CNN model based on T1 contrast-enhanced MRI sequences to achieve high-accuracy CSI prediction. With the development of algorithms and computer modules, a transfer learning method that uses a pre-trained model can reduce the training burden , 23. OurThe accurate identification of PA invasiveness can facilitate the formulation of diagnosis and management and the prognostic evaluation. CSI is an essential indicator for whether chemotherapy or post-operative adjuvant chemotherapy should be considered . TherefoThe CSI was evaluated based on the T1-enhanced MRI sequences. The image samples are readily available without the additional particular sequences or expensive advanced equipment. Sample collection is convenient for multicenter applications and studies. The ML model could increase radiological diagnostic accuracy and unify the pre-operative radiological diagnosis to reduce rater bias. After model classification, neurologists and radiologists can focus on the misidentified cases to determine more radiographic findings of PAs with negative and positive CSI. Furthermore, conventional imaging grading systems have limitations in terms of updating rates, thus decreasing the reliability with the innovation of medical technologies. By contrast, the ML model has a high learning ability, which is characterized by fast updating and adjustment. With the expansion of the image library, the model can be trained to improve the diagnostic accuracy and generalization ability.However, this study has some limitations. For example, although the diagnostic accuracy of the model is higher than that of the Knosp grading system, the diagnostic accuracy and generalization ability should be further improved. In addition, the retrospective nature of the study leads to some limitations. For example, in the absence of complete surgical videos and detailed surgical records of the CSI location and area, image selection relied on a senior neurosurgeon to improve the reliability of whether CSI exists in the selected image. Therefore, the observer error still exists. These factors might influence the predictive performance of the CNN model in the study. Therefore, prospective studies with a reliable record of CSI are required for the ML model training. Nevertheless, our study can demonstrate the feasibility of the CNN model for pre-operative CSI diagnosis.CSI can be accurately identified by using the conventional MR sequences as input into the pre-trained CNN model. We constructed a CNN model that can more reliably determine the CSI than the Knosp grading system. Moreover, the rater bias of the Knosp scale could be reduced effectively.The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation.All investigations conformed to the principles outlined in the Declaration of Helsinki and were performed with permission by the responsible Ethics Committee of the Institutional Review Board of Fuzhou General Hospital and Peking Union Medical College Hospital. The requirement for informed consent was waived because of the retrospective nature of the study.All authors made a substantial contribution to the research design, acquisition, analysis, or interpretation of data; revised the manuscript critically; and approved the final version. The authors thank SW, RW, and MF for reviewing the manuscript. LW carried out statistical analyses. Medical writing and editorial support were provided by HW and WZ.The Fujian Medical University Sailing Fund Project (grant no. 2019QH2043).The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. 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