bluuebunny/crossref_metadata_2025 huggingface dataset:
Durability of concrete with Belite-Gehlenite clinker as fine aggregate
Authors: Kobayashi Arato , Fujiwara Hiromi , Maruoka Masanori , Owada Mizuki , Hayashi Kensuke
Published: September 2022

The Japanese cement industry uses large quantities of industrial waste and by-products as raw materials in the production of cement clinker. Although the amount of industrial waste generated annually has remained almost constant, domestic demand for cement has been falling. In order to maintain the amount of waste re-used by the cement industry, there is a need to explore new ways of utilizing clinker besides in cement production. The proportion of waste used in the production of Belite-Gehlenite clinker featured in this study is about twice as much as in normal clinker. Previous studies have shown that when clinker is used as aggregate in mortar and concrete, clinker hydration products fill cracks as they occur for added self-healing performance. In this study, in addition to the basic characteristics of concrete containing Belite-Gehlenite clinker as fine aggregate, the resistance to cracking of specimens made with the concrete is investigated. Compared with concrete using natural sand, it is confirmed that compressive strength is improved, drying shrinkage is reduced, carbonation is suppressed, and freeze-thaw resistance is maintained. It is also demonstrated that resistance to cracking is improved.
Optimization of Dune Sand-Slag Blended Geopolymer Mortar Using Taguchi Method
Authors: El-Mir Abdulkader , El-Hassan Hilal , El-Dieb Amr , Alsallamin Abdelrahman
Published: September 2022

Achieving optimum performance of geopolymer mortar intended for structural and repair applications is a complex task with various factors being considered prior to production. This study explores the influence of mix design parameters on the fresh and hardened properties of geopolymer mortar made with treated dune sand (TDS) and granulated blast furnace slag (BFS). A total of nine geopolymer mortar mixtures were designed following the Taguchi method for four factors, each with three levels. These factors included BFS replacement rate by TDS, alkali-activator solution to binder ratio (AAS/B), sodium silicate-to-sodium hydroxide ratio (SS/SH), and sodium hydroxide (SH) molarity. The investigated performance quality criteria were flowability, compressive strength, water permeability, and carbon dioxide footprint. The effect of various factors on the responses was assessed through ANOVA while determining the signal-to-noise (S/N) ratios to seek the optimum proportions of mixtures. Results revealed that a mix made with TDS replacement, AAS/B, SS/SH, and SH molarity of 25%, 0.5, 1.5, and 14 M yielded superior performance.
Early-age effect of corn cob ash as a partial replacement for Portland cement in concrete
Authors: Fadele Oluwadamilola A. , Otieno Mike
Published: September 2022

One of the effects of supplementary cementitious materials (SCMs) in concrete is the dilution effect which is as a result of partially replacing Portland cement with SCMs. The dilution effect of corn cob ash (CCA) with respect to strength gain and transport properties of concrete is the focus of this study. 100 mm concrete cubes were prepared with corn cob ash partially replacing Portland cement at 15% and 30% using w/b ratio of 0.4 and 0.6. The effect of CCA replacement level on the compressive strength development between 3 and 28 days, and transport properties at 28 days of curing was done. This was compared to the effect of fly ash at the same replacement level and 100% Portland cement content. The results showed that compressive strength decreases with increasing ash content and increases with increasing curing age. The dilution effect of CCA was more pronounced at the two replacement levels than fly ash with a marginal gain or strength loss compared to w/c ratio corresponding to each w/b ratio. The oxygen permeability index obtained for CCA concrete were lower compared to that of fly ash concrete at the same replacement levels and PC concrete at the same w/b ratio. Also, the water sorptivity index and chloride conductivity index for CCA concrete were higher than that of fly ash and PC concrete at the same w/b ratio.
Chloride penetration resistance of fine recycled aggregate concrete
Authors: Amadi I. G. , Beushausen H. , Alexander M.G. , Surana S.
Published: September 2022

This study investigates the chloride penetration resistance of fine recycled aggregate concrete (FRAC). Six concrete mixes comprising 0.45 and 0.55 w/b were prepared using fine recycled aggregates (FRA) at 0, 25 and 50% by volume replacement of natural sand. The chloride penetration resistance of the concrete was tested using the surface electrical resistivity (SER), chloride conductivity index (CCI), and the bulk diffusion tests. The SER and CCI tests were conducted after 28 days and 180 days of wet curing, while the bulk diffusion test was carried out after 28 days of wet curing and 180 days of exposure to chloride solution. Results show that the SER of FRA concrete was comparable to the control concrete, at all ages tested. The 28-day CCI of the concrete was impacted as FRA replacement levels increased, whereas at 180 days of testing, the FRA concrete mixes showed more significant improvement in CCI than the control natural aggregate concrete (NAC). The bulk diffusion results indicate that, for each w/b, the chloride diffusion profiles of the control and FRA concrete are comparable.
Modelling the cracking of fresh concrete
Authors: Combrinck Riaan , Meyer Marnu , Boshoff William P.
Published: September 2022

The cracking of fresh concrete, while still in a plastic state, includes both plastic settlement and plastic shrinkage cracking, which starts once the concrete is cast to around the final setting time. The cracking process is complex and is influenced by numerous factors which include the climate, mix proportions, element geometry and construction procedures. Preventing these cracks therefore remains a problem in practice. One of the reasons for this is the lack of a model that can be used to determine the location, timing and severity of the cracking before the cracking occurs. The main challenges with such a model are the testing of the fresh concrete to determine the tensile material properties, the appropriate constitutive law needed, and the time dependency of material properties as well as the anisotropic volume change. This paper presents a finite element model that uses a total strain smeared cracking approach and accounts for both the time dependency of material properties and the anisotropic volume change. The model gives an adequate representation of the cracking behaviour of fresh concrete for extreme climates but not for normal to moderate climates, mainly due to the size discrepancy between the interior and surface cracks during experiments as well as the relaxation of stresses that are not accounted for in the model. A parameter study showed that both the settlement and shrinkage strains significantly influence and therefore govern the size of the final plastic crack, while the material mechanical properties only influence the time of crack onset and rate of crack widening.
The tensile deformation and capillary pressure build up in fresh concrete
Authors: Meyer Marnu , Khan Yaseen , Combrinck Riaan
Published: September 2022

During the plastic state of concrete, any hindrance or resistance of the free volume change in plastic concrete induce tensile stresses and or strains in the concrete element. Crack formation is expected to occur if the tensile stress and strain is greater than the capacity of the concrete. Investigation into the tensile properties and relaxation behaviour of plastic concrete was carried out using a direct tensile testing machine. The capillary pressure was measured during the tensile tests in low evaporation conditions, as well as in a climate controlled chamber where the concrete was exposed to high evaporation conditions. Most of the measured strength gain (tensile capacity) of the concrete is due to the capillary pressure in the pores of the fresh concrete which keeps the particles together by means of free water in the concrete during the early stiffening phase of the concrete. Later the hydration products bridge the pores which provides strength to the concrete. The capillary pressure results indicate how the rate of hydration influence the interconnectivity of the pores, and the contribution to the measured strength gain of the fresh concrete. The capillary pressure measurements during tensile tests revealed that the mechanism behind relaxation is the negative capillary pressure build-up induced by the mechanical tensile strain. The results also showed a correlation between the build-up of the capillary pressure in the concrete and the tensile deformation of the fresh concrete where the capillary pressure increased as the tensile load increased.
Corrosion Monitoring of Reinforced Concrete Structures – Actual Research Results and New Guidelines
Authors: Fraundorfer Andreas , Dauberschmidt Christoph
Published: September 2022

The corrosion of reinforcing steel in concrete, caused by de-icing salt or carbonation, represents a considerable repair expense in Germany every year. Electrochemical corrosion monitoring can be a helpful tool to determine the ingress of the depassivation front into a chloride exposed structure. The installation of appropriate sensors in existing structures can make the success of the repair verifiable after the repair work has been completed. To date, however, there is no set of rules for corrosion monitoring. In 2018, a leaflet B12 of the DGZfP [1] was published for the first time, which can serve as a guideline. Furthermore, in the last 3 years a broad-based research project has been carried out in Germany on open questions of corrosion monitoring. The knowledge gained in this way will be incorporated into a DAfStb-Leaflet that is currently being processed. Both the relevant findings of the investigated part at the University of Applied Sciences Munich HM and the content of the leaflet are presented.
Assessment of cantilevered concrete balconies by means of practically oriented evaluation tools
Authors: Craeye Bart , Wittocx Lydia , Renne Neel , Minne Peter , Caspeele Robby
Published: September 2022

Facing the aging building stock, challenging times can be expected with a sharp increase of reinforced concrete buildings requiring maintenance, repair and/or replacement. For the condition assessment of existing reinforced concrete structures an in-depth and reliable inspection strategy and evaluation is essential to come to a durable and service-life extending repair strategy. A stepwise protocol to evaluate the condition and remaining bearing capacity of cantilevered reinforced concrete (RC) balconies is presented in this paper. Corrosion causing the reduction of the steel section, incorrect positioning of the reinforcement and/or higher loads are the main reasons service life might not be reached or the failure of the balcony can occur. As mentioned in EN 1504-9 and NEN 8700, an adequate diagnosis prior to repair showing the cause and extent of the damage is important (i) to determine the actual bearing capacity, (ii) to make an estimation of the residual lifespan and (iii) to select a durable repair technique and/or define maintenance requirements. In this paper a newly developed protocol for the assessment of the condition and the bearing capacity of the cantilevered RC balconies of a high-rise residential building is demonstrated. A semi-probabilistic method is used by applying partial safety factors based on Eurocode guidelines and fib Bulletin 80. The condition of the structure is determined based on NEN2767 regulations. As corrosion is the main contributor to the degradation of existing concrete structures, a chloride contaminated building with damaged reinforced concrete balconies is selected as case study in order to demonstrate the applicability of the developed protocol and tools.
The effect of curing, specimen thickness, and saturation on surface resistivity of concrete
Authors: Surana Saarthak , Beushausen Hans , Alexander Mark
Published: September 2022

Electrical resistivity measurements are used to assess the potential durability of concrete. The surface resistivity method is a popular method because of the ease of testing, non-destructive nature, and time efficiency. The moisture state of concrete has a significant influence on the resistivity results. Laboratory specimens cured using practical curing methods should be saturated before testing to eliminate this effect and avoid incorrect interpretation of the results. However, the available standard test methods for surface resistivity do not deal with this issue. Consequently, an experimental study has been conducted on the effect of drying on concrete resistivity values, as reported in this paper. The results show that a reduction in the specimen thickness can improve the ability of the surface resistivity method to be used for assessing curing effectiveness.
Microscopic assessment of ASR-affected columns after 20 years in service
Authors: Ahmed Hesham , Zahedi Andisheh , Sanchez Leandro
Published: September 2022

Deterioration signs were observed on the concrete surface of the exterior columns of the SITE building located at the University of Ottawa, Ottawa (Ontario, Canada) which demonstrated the potential presence of a concrete damage mechanism, suspected to be alkali-silica reaction (ASR). To investigate the root cause of this deterioration, a visual inspection was conducted to select concrete members for coring. Damage development in the extracted cores was then evaluated through various microscopic techniques to identify the cause and extent of deterioration. First, the petrographic examination was carried out with the aim of detecting the cause of damage in the extracted core specimens through the analysis of damage features; confirming the presence of ASR in the selected elements Afterwards, the Damage Rating Index (DRI), a semi-quantitative microscopic procedure, was used to evaluate the extent of the damage. Data collected during the visual inspection and petrographic examination will be presented and analyzed. Moreover, based upon the analysis of DRI results, the induced expansion levels in affected columns will be discussed, along with potential implications on their structural performance.
Emergency rehabilitation of Selby interchange on M2, in Johannesburg, South Africa
Authors: Strydom Johnnie , da Silva Jared , Kongolo Odilon
Published: September 2022

In this paper, the retrofitting and rehabilitation of the M2 Selby interchange, on the M2 in Johannesburg, Gauteng, South Africa, is presented. After noting large shear cracks on the pier columns, the highway had to be closed down, for 10 months. The client for the project was the Johannesburg Roads Agency (JRA), the contractor was Stefanutti Stocks Civils, and the consultant was WSP. The project commenced with the design of jacking towers which were used to jack up and support the drop-in slabs. The support system was designed to be used as a kit that can be reused in future. The demolition of the piers posed some difficulties due to the small working area within the constraints of the jacked slabs, which remained in the jacked position. The piers were designed in accordance with TMH7. A key design focus was the creep calculation, due to the unique geometry of the mushroom heads. Granite aggregates were chosen to reduce the creep and the cantilever ends were precambered. The jacked slabs were lowered and aligned only at the end of the project timeline just in time for the Thorma joints and asphalt to be added before opening the bridge to the public.
Concrete substrate moisture requirements for durable concrete repairs – a field study
Authors: Bissonnette Benoit , Vaysburd Alexander M. , von Fay Kurt F. , Harrell Shannon J. , Courard Luc , Garbacz Andrzej
Published: September 2022

In concrete repair specifications, the required moisture condition of the substrate, which can play an important role for bond development, and, ultimately, on the long-term repair / overlay durability, is generally ill-defined and addressed without due consideration to the given substrate characteristics. The standard specification, if any, is to require saturated surface dry (SSD) condition of the substrate prior to application of cementitious repair materials, which is theoretically achieved after saturating the substrate and then letting the surface just start to dry out. This does provide an intuitive solution founded on rational considerations, but it has never really been precisely defined, measured, nor validated. The influence of substrate surface moisture on the bond between the existing concrete and the new repair material is an issue of significant importance. This paper revisits the question, in light of results from a project designed to develop guidelines for moisture conditioning of a concrete substrate prior to a cementitious repair, which was part of a larger effort to develop guidelines for surface preparation of concrete prior to repair. Over the course of the project, multiple series of test slabs were repaired after being subjected to different surface moisture conditioning and then tested for bond strength tests at different ages. The findings are discussed, together with those from previous studies, and recommendations are issued.
Investigating the effects of anti-corrosive coatings on the bond between corrosion-damaged rebar and concrete repair materials
Authors: Muhammad Ameen Moolla , Jarratt Nicholas , Beushausen Hans
Published: September 2022

Reinforcement corrosion causes destruction to the steel by a loss in cross section and rib height, which can affect the bond between steel and concrete. During repair of corrosion-damaged reinforced concrete members, a protective coating is usually applied to the cleaned corroded steel. There is, however, little information available on the bond performance of repair coatings. Furthermore, the effect of their coating thickness and other parameters like rebar diameter, corrosion degree and repair material properties are not well understood when considered in parallel with repair coatings. This paper seeks to contribute towards understanding the use of anti-corrosive coatings and the influence of their thickness on the bond between cleaned steel reinforcement and repair materials, when used in combination with different bar geometries at varying degrees of corrosion damage. In this investigation, two high tensile steel bars, Y12 and Y16, were considered. Rebar corrosion damage levels of 0%, 10% and 20% (of steel mass loss) were simulated by mechanical grinding of sound rebar samples to represent the condition of cleaned corroded rebar. A commercially available epoxy-modified, cementitious coating material was applied to the steel in one or two coats, with each coat being 0.6 mm thick. Three repair materials with CEM I 52.5N were considered in this study, which included one concrete with a w/b ratio of 0.45 and two mortars with w/b ratios of 0.47 and 0.65. Pull-out testing was conducted on 108 specimens, and the results analysed by means of the one-way ANOVA test to assess the effect of mainly coatings and other parameters on the bond. The results indicate applying coatings to 10% and 20% corroded steel does not significantly reduce the bond for the M65 and C45 mixes. Furthermore, the difference between one and two coats had little influence on the bond of corroded steel for all rebar geometries and repair mixes.
UHPC overlay as sustainable solution to preserve old concrete structures
Authors: Kothari Ankit , Rajczakowska Magdalena , Cwirzen Andrzej
Published: September 2022

Concrete structures exposed to harsh environments, especially including bridges, harbor structures are often suffered from durability problems. Typical external signs include surface deterioration, cracking caused by for example sulphate attack, frost action or reinforcement corrosion. All are strongly linked to the porous microstructure of the binder matrix and chemical decomposition of certain phases. Full replacement of deteriorated concrete structures is costly and can be troublesome for their users. The increasing demand to reduce the carbon footprint and to prolong the service life of concrete structures adds yet another argument to restore the existing structures. One alternative is to use very dense Ultra-High-Performance concrete (UHPC) as an external protective coating. The goal of this study was to determine the interfacial bonding characteristics between a damaged normal concrete (NC) and the applied thin layer of the UHPC. To curb the CO2 emission, UHPC is produced by substituting 50 wt% of Portland cement with a fine limestone powder. Fresh and hardened properties, shrinkage and frost durability have been evaluated. Mechanical properties were determined on a full-scale hybrid element using ultrasonic pulse velocity (UPV) and bond test (pull-off test). The results showed a significant increase of mechanical properties. Despite the applied thin layer of UHPC and volumetric restrain from the substrate normal concrete (NC) only limited surface shrinkage cracks were observed. The bond test and UPV showed good excellent values.
Volume change behavior of cement-based repair materials labelled as shrinkage-compensating, shrinkage-compensated or nonshrink
Authors: Bissonnette Benoit , Molez Laurent , Certain Pierre-Vincent , Lamothe Charles , Jolin Marc , Gagné Richard
Published: September 2022

The labels shrinkage-compensating, shrinkage-compensated and nonshrink found in the technical documentation of many proprietary repair materials are all intended in principle to describe systems that exhibit no or little net contraction as a result of shrinkage. In practice, however, these terms are of limited significance in the selection of repair materials without appropriate test data on time-dependent volume changes. This paper provides clarifications on the dimensional behavior of shrinkage-compensating materials and uses experimental findings to emphasize the shortcomings in the information provided in the data sheets of many repair materials labelled as such. In view of a more effective and reliable use of cementitious shrinkage-compensating repair materials, recommendations are made to improve and uniformize the content of the technical data sheets.
Shear strengthening of concrete T-beams with lateral layers of UHPC
Authors: Liu Tongxu , Charron Jean-Philippe
Published: September 2022

Concrete T-beams are commonly used in building slab systems and bridge decks. They may require strengthening in shear when they are deteriorated or when loading requirements increased. This research project studied the shear behaviour of concrete T-beams using cast-in-place Ultra High-Performance Concrete (UHPC) layers as a lateral strengthening method avoiding beam depth modification. Three UHPC strengthened beams together with one reference reinforced concrete beam were tested in monotonic three-point bending. Parameters investigated include the thickness of UHPC layers and the presence of steel anchors at the UHPC-concrete interface. A digital image correlation (DIC) technique was used to investigate the strain distribution of T-beams during the testing. Strain distribution, failure modes and strengthening effects provided by the UHPC lateral strengthening were analyzed. Results show that UHPC strengthening can substantially improve the stiffness and shear capacity of concrete T-beams, 25 and 50 mm lateral layers increased by 102% and 113% the T-beam shear capacity, respectively. Typical bending-shear behaviour were observed on each strengthened beam with UHPC layers. A final shear failure was observed in the T-beam with 25 mm UHPC layers and 50 mm UHPC layers without anchors, while a combination of shear and bending failure was noted in the T-beam with 50 mm UHPC layers and steel anchors. The steel anchors at the UHPC-concrete interface can further increase the ultimate shear capacity and beam stiffness, but at a limited extent. Therefore, experimental results confirmed that cast-in-place UHPC lateral layers are an effective way to strengthen existing concrete T-beams with inadequate shear capacity
Preventing plastic shrinkage cracking by monitoring the capillary pressure build-up in self-compacting concrete
Authors: Deysel Renier , Boshoff William , Smit Martha
Published: September 2022

Plastic shrinkage cracking is a problem for the service life, aesthetics and durability of concrete members. It occurs when tensile stresses are induced in fresh concrete, through plastic shrinkage that is restrained. Plastic shrinkage is caused by negative capillary pressure build-up, but the capillary pressure of fresh concrete can be controlled to prevent plastic shrinkage. In this paper, the control of capillary pressure to prevent plastic shrinkage cracking using high-capacity capillary pressure sensors is explored. The capillary pressure behaviour of a self-compacting concrete mix design in various evaporation rates was determined. Capillary pressure boundaries for concrete wetting to relieve tensile stresses were identified. The effectiveness of wetting fresh concrete at a predefined capillary pressure boundary was investigated.
Interactions between hydrated cement pastes and aggressive ammonium: experimental batches characterization
Authors: Giroudon Marie , Roosz Cédric , Bista Mehdi , Peyre Lavigne Matthieu , Lacarrière Laurie , Bertron Alexandra
Published: September 2022

Agricultural and food industries concrete facilities face chemically aggressive conditions that can damage their microstructure and reduce their lifespan. They are particularly exposed to ammonium-rich environments from natural microbial activity. The poorly crystalline mineralogy of hydrated cement pastes, the compositional variability of the phases and their reactivity make the geochemical behaviour of such materials difficult to investigate and predict over both large periods of time and wide variety of chemical compositions. This work aims (i) to assess the stability of the cement phases involved in ammonium-rich conditions as well as to identify the alteration products, and (ii) to understand the mechanisms and intensity of alteration. To do this, experiments were carried out both on OPC paste powder and on monolithic OPC pastes, degraded by an ammonium nitrate solution in semi-batch conditions. The powder was gradually added to the aggressive solution while the monoliths were immersed for 16 weeks in regularly renewed solution. The pH and the concentration of the chemical elements in solution were monitored over the experiments. The microstructural, chemical and mineralogical changes of the samples were analysed by scanning electron microscopy, electron probe micro-analysis and X-Ray diffraction and showed phenomena of dissolution, leaching and carbonation.
High-performance Reactive Magnesium Cement Incorporating Hollow Natural Fiber and Silica Sand
Authors: Wu Bo , Qiu Jishen
Published: September 2022

Global warming caused by CO2 emissions makes reactive magnesium cement (RMC) increasingly attractive due to its ability to sequester CO2, however, the diffusion of CO2 in RMC is severely limited by the dense hydrated magnesium carbonates (HMCs) formed on the outer layer. This work utilizes hollow natural fiber (e.g., sisal fiber) to facilitate the diffusion of CO2 into the deep part of the RMC specimen. Combining with adding silica sand as a filling agent, the mechanical strength can be enhanced from 42.4 MPa of the control group to 92.6 MPa of the specimen with 2 vol.% sisal fiber, this is attributed to that the addition of sisal fiber significantly enhances the carbonation depth. FTIR and XPS results further prove that the addition of 2 vol.% or more sisal fiber can improve the carbonation degree by over 200%, leading to a sharp reduction of CO2 emission from 37 kg/(m3>MPa) of the control group to 12.1 kg/(m3∘MPa) of the specimen with 2 vol.% sisal fiber. Therefore, adding hollow natural fiber and silica sand to RMC can be a promising approach to make RMC stronger and more sustainable.
Design of smart cementitious composites based on multi-walled carbon nanotubes (MWCNTs) using probe ultrasonicator for dispersion
Authors: Shahzad Shaban , Toumi Ahmed , Balayssac Jean-Paul , Turatsinze Anaclet
Published: September 2022

The purpose of this study is to develop smart cementitious material by incorporating multi-walled carbon nanotubes (MWCNTs). Two different types of carbon nanotubes (CNT) were dispersed using probe ultrasonicator; (i) Pristine CNT (P-CNT), and (ii) Functionalized CNT through annealing (A-CNT). Percolation threshold and optimum content of CNTs were determined by measuring electrical resistivity, porosity, compressive and flexural strengths at various contents of CNTs (0, 0.5 %, 0.75 %, and 1 % with respect to mass of cement). Self-sensing study was also carried out on smart material by relating the electrical properties with cyclic compressive loading. For this purpose, the electrical response was recorded with Wheatstone Bridge (WSB) circuit. The effect of curing and saturation degree of specimens on the resistivity pattern was also discussed. The results of electrical resistivity and mechanical properties showed that the content of CNTs should be at least 0.75 % to develop smart cementitious materials with a significant sensitivity and without detrimental effect on the mechanical properties. Moreover, smart material incorporating pristine CNT provides better sensitivity of self-sensing response as compared to the annealed CNT. Self-sensing test results also showed that with the increase in the content of CNT, sensitivity and repeatability of the sensing response were improved.
Feasibility of using clays from Southeast European deposits in limestone calcined clay cements
Authors: Flegar Matea , Serdar Marijana , Londono-Zuluaga Diana , Scrivener Karen
Published: September 2022

Recently, the cement industry has faced new challenges in addition to the environmental constraints of the last decade. The decline in availability and current inconsistent prices of common supplementary cementitious materials (SCMs), such as by-products from the iron industry or coal-fired power plants, have opened the search for more reliable materials. Research on cements containing calcined clays now serve as a possible solution to the forementioned problems. Clays containing the mineral kaolinite in sufficient quantities, when calcined and mixed with limestone powder, produce hydration products that can improve the strength and durability of concrete. In addition, the production of limestone calcined clay is reported to be less CO2 intensive, but this eco-efficient solution is viable only if the materials are locally available. For this reason, this study investigates the possibility of using natural clays from the Southeast European region (SEE) as cement replacements. A systematic experimental study was conducted on 18 different clays from 13 different deposits to determine the physical and mineralogical composition of the raw clays, their reactivity and mortar strength. The results were then related to the environmental contributions they might have in comparison with ordinary Portland cement in concrete.
A textile reinforcement method for 3D printed concrete
Authors: Janse van Rensburg JJ , Babafemi Adewumi J. , Combrinck Riaan
Published: September 2022

The reinforcement of 3D printed concrete elements has proven to be a significant challenge that needs to be addressed. However, before reinforcement can be applied, the behaviour of the consequent composite materials must first be studied. This study, therefore, investigates the macromechanical behaviour of AR glass fibre textile material as reinforcement in terms of its flexural performance, to determine whether it is a feasible solution. During this study, elements, consisting of four layers, are printed flat on the surface bed of the printer and are reinforced by a textile mesh in between subsequently printed layers. The specimens are reinforced at different locations, with different geometrical orientations as well as different filament orientations, and are then compared. The flexural performance is quantified by conducting four-point bending tests 28 days after printing. The results of the tests show that by adding this specific mesh, the average flexural strength of the elements increases significantly. Furthermore, elements with the warp yarns aligned with the printed filament have increased flexural strength. During the testing, it is also discovered that voids form underneath the textile mesh when applied between the layers and that these voids influence on the performance of the elements.
Flexural strength of fibre reinforced concrete in relation to the angle of magnetically orientated fibres
Authors: Carrera Kristýna , Künzel Karel , Papež Václav , Sovják Radoslav , Kheml Přemysl , Fornůsek Jindřich , Mára Michal , Konrád Petr
Published: September 2022

This paper focuses on high-performance fibre-reinforced concrete and its flexural strength concerning fibre orientation. The orientation is provided by a fully controlled special device. This device can align the fibres in fresh concrete using a magnetic field. The specimens are inserted into the device at different angles to ensure different fibre orientations concerning the longer side of the sample, which corresponds to the direction of the main tensile stresses. Specifically, angles of 0 °, 30 #x00B0;, 60 ° and 90 ° are tested and compared with each other and with reference specimens that are not exposed to a magnetic field. All samples are measured by a non-destructive method. This method was developed in our previous research and is based on measuring the quality factor Q of a measuring coil using an impedance meter. The samples are inserted into a measuring coil connected to an impedance meter. Flexural strength is obtained from the results of a three-point bending test. All samples are tested until complete failure.
Implementing a Perinatal Depression Screening in Clinical Routine: Exploring the Patientʼs Perspective
Authors: Trinh Thuy Giang , Schwarze Cornelia E. , Müller Mitho , Goetz Maren , Hassdenteufel Kathrin , Wallwiener Markus , Wallwiener Stephanie
Published: September 2022

Introduction Perinatal depression (PND) is a frequently observed mental disorder, showing a prevalence of up to 20% and resulting in unfavorable maternal and neonatal outcomes. Targeted screening for PND offers the potential to identify and treat undiagnosed cases and help prevent its deleterious consequences. The aim of the present study was to evaluate participantsʼ personal attitudes and acceptance of a routine screening program for PND in pregnancy care, identify any potential underlying factors, and appraise the general perspective on perinatal mental health problems.

Methods In total, 732 women in their second trimester of pregnancy took part in a PND screening program that was incorporated in routine prenatal care using the Edinburgh Postnatal Depression Scale (EPDS) and completed a web-based survey on screening acceptance.

Results Participants viewed PND screening as useful (78.7%, n = 555/705), especially in terms of devoting attention to perinatal mental health problems (90.1%, n = 630/699), easy to complete (85.4%, n = 606/710), and without feelings of discomfort (88.3%, n = 628/711). Furthermore, women with previous or current mental health issues rated the usefulness of screening significantly higher, as did women with obstetric risks (p < 0.01 – p = 0.04). The final regression model explained 48.4% of the variance for screening acceptance.

Conclusion Patient acceptance for PND screening was high in our study cohort, supporting the implementation of screening programs in routine pregnancy care with the potential to identify, sensitize, and treat undiagnosed patients to reduce stigmatization and offer access to tailored dedicated PND care programs.
AGO Recommendations for the Surgical Therapy of Breast Cancer: Update 2022
Authors: Banys-Paluchowski Maggie , Thill Marc , Kühn Thorsten , Ditsch Nina , Heil Jörg , Wöckel Achim , Fallenberg Eva , Friedrich Michael , Kümmel Sherko , Müller Volkmar , Janni Wolfgang , Albert Ute-Susann , Bauerfeind Ingo , Blohmer Jens-Uwe , Budach Wilfried , Dall Peter , Fasching Peter , Fehm Tanja , Gluz Oleg , Harbeck Nadia , Huober Jens , Jackisch Christian , Kolberg-Liedtke Cornelia , Kreipe Hans H. , Krug David , Loibl Sibylle , Lüftner Diana , Lux Michael Patrick , Maass Nicolai , Mundhenke Christoph , Nitz Ulrike , Park-Simon Tjoung Won , Reimer Toralf , Rhiem Kerstin , Rody Achim , Schmidt Marcus , Schneeweiss Andreas , Schütz Florian , Sinn H. Peter , Solbach Christine , Solomayer Erich-Franz , Stickeler Elmar , Thomssen Christoph , Untch Michael , Witzel Isabell , Gerber Bernd
Published: September 2022

The recommendations of the AGO Breast Committee on the surgical therapy of breast cancer were last updated in March 2022 (www.ago-online.de). Since surgical therapy is one of several partial steps in the treatment of breast cancer, extensive diagnostic and oncological expertise of a breast surgeon and good interdisciplinary cooperation with diagnostic radiologists is of great importance. The most important changes concern localization techniques, resection margins, axillary management in the neoadjuvant setting and the evaluation of the meshes in reconstructive surgery. Based on meta-analyses of randomized studies, the level of recommendation of an intraoperative breast ultrasound for the localization of non-palpable lesions was elevated to “++”. Thus, the technique is considered to be equivalent to wire localization, provided that it is a lesion which can be well represented by sonography, the surgeon has extensive experience in breast ultrasound and has access to a suitable ultrasound device during the operation. In invasive breast cancer, the aim is to reach negative resection margins (“no tumor on ink”), regardless of whether an extensive intraductal component is present or not. Oncoplastic operations can also replace a mastectomy in selected cases due to the large number of existing techniques, and are equivalent to segmental resection in terms of oncological safety at comparable rates of complications. Sentinel node excision is recommended for patients with cN0 status receiving neoadjuvant chemotherapy after completion of chemotherapy. Minimally invasive biopsy is recommended for initially suspect lymph nodes. After neoadjuvant chemotherapy, patients with initially 1 – 3 suspicious lymph nodes and a good response (ycN0) can receive the targeted axillary dissection and the axillary dissection as equivalent options.
Endoscopy training in the Netherlands: a national survey among gastroenterology residents
Authors: Mousset Robert A. , de Vos tot Nederveen Cappel Wouter H. , Pierie Jean-Pierre E.N. , Brand Paul L.P. , Langers Alexandra M.J.
Published: September 2022

Background and study aims Training in endoscopy is a key objective of gastroenterology residency. There is currently no standardized or systematic training approach. This study evaluated and compared the current status of gastrointestinal endoscopy training programs in all teaching hospitals in the Netherlands from a resident perspective.

Materials and methods A national online survey with open and closed questions on gastrointestinal endoscopy training was administered to all gastroenterology residents (N = 180) in the eight educational regions in the Netherlands.

Results One hundred residents who had already started endoscopy training were included in the analyses. Sixty-five residents (65 %) were satisfied with their endoscopy training program. Participation in a preclinical endoscopy course was mandatory in seven of eight educational regions. Residents from the region without a mandatory endoscopy training course were significantly less likely to be satisfied with their endoscopy training program (32 %, P = .011). Criteria used to determine the level of supervision differed greatly between teaching hospitals (e. g. assessed endoscopy competence, predefined period of time or number of procedures). Only 26 residents (26 %) reported uniformity in teaching methods and styles between different supervising gastroenterologists in their teaching hospital.

Conclusions Although most gastroenterology residents were satisfied with the endoscopy training program and endoscopy supervision in their teaching hospital, this study identified considerable local and regional variability. Future studies should be conducted to evaluate the trainers’ perspective and trainers’ behavior during endoscopy training sessions, which might eventually lead to the development of best practices regarding endoscopy training, including standardization of training programs and supervision methods.
Endoscopic treatment of intussusception due to small intestine polyps in patients with Peutz-Jeghers Syndrome
Authors: Oguro Kunihiko , Sakamoto Hirotsugu , Yano Tomonori , Funayama Yohei , Kitamura Masafumi , Nagayama Manabu , Sunada Keijiro , Lefor Alan Kawarai , Yamamoto Hironori
Published: September 2022

Background and study aims Intussusception caused by intestinal polyps in patients with Peutz-Jeghers syndrome usually requires laparotomy. Patients following successful endoscopic reduction using double-balloon endoscopy (DBE) have been reported. The aim of this study was to evaluate the feasibility of endoscopic treatment of intussusception.

Patients and methods We retrospectively reviewed patients who underwent DBE for intussusception due to small intestine polyps in patients with Peutz-Jeghers syndrome from January 2004 to June 2020.

Results Twenty-seven (antegrade 22, retrograde 5) DBEs were performed in 19 patients with 25 sites of intussusception identified during the study period. If the intussusception remained once the endoscope reached the site, endoscopic reduction of the intussusception was performed as needed (15 sites). Ultimately, endoscopic resections (8 sites) or ischemic polypectomies (16 sites) of the polyp causing the intussusception were completed at 24 sites. Only one site could not be treated endoscopically and was treated surgically. The final per-site and per-patient success rates of endoscopic treatment were 96 % (24/25) and 95 % (18/19) respectively. Two patients developed mild acute pancreatitis and one patient developed intussusception after the procedures, both of which were treated non-operatively.

Conclusions Endoscopic treatment of intussusception is feasible to avoid laparotomy in patients with Peutz-Jeghers syndrome.
A Systematic Analysis of the Impact of an Ambulatory Ophthalmology Urgent Care Clinic
Authors: Park Sally S.E. , Vij Rohin , Wu Jeff , Zarrin Bryan , Moon Jee-Young , Oliveira Jason , Schultz Jeffrey S. , Shrivastava Anurag
Published: September 2022

Importance A same-day ophthalmic urgent care clinic can provide efficient eye care, a rich educational environment, and can improve patient experience.

Objective The aim of this study was to systematically evaluate volume, financial impact, care metrics, and the breadth of pathology of urgent new patient encounters based on their site of initial presentation.

Design, Setting, and Participants A retrospective analysis was performed on consecutive urgent new patient evaluations in our same-day triage clinic at the Henkind Eye Institute at Montefiore Medical Center between February 2019 and January 2020. The cohort of patients who presented directly to this urgent care clinic were referred to as the “TRIAGE” group. Patients who initially presented to an emergency department (ED), and were subsequently referred to our triage clinic, are referred to as the “ED + TRIAGE” group.

Main Outcomes and Measures Visits were evaluated on a variety of metrics, including diagnosis, duration, charge, cost, and revenue. Furthermore, return to the ED or inpatient admission was documented.

Results Of 3,482 visits analyzed, 2,538 (72.9%) were in the “TRIAGE” group. Common presenting diagnoses were ocular surface disease (n = 486, 19.1%), trauma (n = 342, 13.5%; most commonly surface abrasion n = 195, 7.7%), and infectious conjunctivitis (n = 304, 12.0%). Patients in the “TRIAGE” group, on average, were seen 184.6% faster (158.2 vs. 450.2 minutes) than patients in the “ED + TRIAGE” group (p < 0.001). The “ED + TRIAGE” group were furthermore found to generate 442.1% higher charges ($870.20 vs. 4717.70) and were associated with 175.1% higher cost ($908.80 vs. 330.40) per patient. The hospital was found to save money when noncommercially insured patients with ophthalmic complaints presented to the triage clinic instead of the ED. Patients seen in the triage clinic had a low rate of readmission to the ED (n = 42, 1.2%).

Conclusions and Relevance A same-day ophthalmology triage clinic provides efficient care, while providing a rich learning environment for residents. Less wait time with direct access to subspecialist care can help improve quality, outcome, and satisfaction metrics.
Homoeopathic Medicine Teucrium marum varum in Treatment of Nasal Polyps Associated with Chronic Rhinosinusitis: A Case Report
Authors: Bhattacharjee Baidurjya , Dutta Abhijit
Published: September 2022

Background Nasal polyps are one of the most prevalent and significant clinical problems. No suitable therapy has been identified except surgical intervention, which is also associated with a high chance of recurrence.

Case This article reports two cases presented primarily with nasal polypus. The prescription of Teucrium marum varum was made specifically based on the location of the polyps. In the first case, there was prompt relief of the symptoms. But in the second case, non-individualised specific application of the remedy could not relieve the patient of his symptoms. Relief was obtained by giving medicines based on the indicated characteristic symptom. Both the cases were followed up for an additional 6 months following the total disappearance of symptoms to rule out any recurrence.

Conclusion Specific remedies act very conditionally depending on the presenting characteristics and peculiarities of the case. Therefore, depending solely on the specific medicines for any disease condition is not advised. Causal attribution cannot be drawn from case reports but shows a direction for consideration of homoeopathic specifics in such cases. Adequately controlled trials with rigorous methodology are required to prove the efficacy beyond doubt.
1,4-Reduction of α,β-Unsaturated Ketones through Rhodium(III)-Catalyzed Transfer Hydrogenation
Authors: Yu Xuewen , Zhou Wang , Wan Saihong
Published: September 2022

A rhodium(III)-catalyzed transfer hydrogenation of unsaturated ketones was developed. The simple catalytic system could be used for the 1,4-reduction of unsaturated cyclic, acyclic ketones, diketones, as well as β-ketoester, and a variety of functional groups were well-tolerated, affording products in moderate to excellent yields.
Nation branding vs. nation building revisited: Ukrainian information management in the face of the Russian invasion
Authors: Bolin Göran , Ståhlberg Per
Published: September 2022

This article re-evaluates some of the previous assumptions made related to the communication practices and information management in Ukraine since before the Euromaidan revolution in 2013. We highlight two points where previous knowledge about nation branding and nation building must be rethought in light of the latest developments Firstly, nation branding is no longer exclusively an activity that is directed to an audience of foreign investors and tourists, but also toward the international field of politics. Simultaneously, it is also clearly directed toward a domestic audience—the citizens of Ukraine. Secondly, this means that there may no longer be any sharp distinction between nation building and nation branding—at least not in times of an ongoing armed conflict.