bluuebunny/crossref_metadata_2025_split huggingface dataset:
Probabilistic service life prediction of cracked concrete using numerical and engineering models
Authors: L. Schultheiß Annika , Patel Ravi A. , Dehn Frank 
Published: December 2023

AbstractChloride ingress induced depassivation of reinforcing steel leading to corrosion is a major durability concern for concrete structures. The influence of the presence of cracks commonly occurring in concrete structures on chloride ingress should be accounted to improve the accuracy of service life predictions. This study investigates the depassivation probability of the reinforcement in both cracked and uncracked concrete using both analytical and 1D numerical models. The probabilistic service life prediction is realized using the Monte Carlo simulation to incorporate the uncertainty and variability in the input variables. For uncracked concrete the result of the numerical model agreed well with the fib chloride model. For cracked concrete, the numerical simulation suggests that the optimal engineering approach to account for cracks in a service life analysis is the adaptation of crack depth. Although, the approach could lead to an overestimation of chloride concentration because the 1D numerical simulation did not consider lateral diffusion in cracked concrete.
Performance of manhole under severe condition in Japan
Authors: Ishitsuka Kei , Kawakami Makoto , Kuwahara Yuki , Kai Nobuhiro 
Published: December 2023

AbstractJapan is prone to natural disasters such as earthquakes and torrential rains. Since those disasters have become more severe, extending the life of infrastructure is an urgent issue. Modern sewer system in Japan have been constructed since 1884, and regular inspection, cleaning, and repair are essential to prolonging the life of sewage pipes. Manholes, which are entrances to sewage systems, can be regarded to be one of the important structures that support our safe, secure, and comfortable lives.In this paper, two main parts composed of a manhole, a cover and its bottom, are introduced. The cover made of spheroidal graphite cast iron (cast iron cover) and the manhole bottom made of resin concrete have been developed to extend the life and performance of manholes. The cast iron cover has been made lighter by optimizing the material and structure, does not rattle even when automobiles pass through it at high speed, and automatically releases pressure when the pressure in pipe rises. In addition, the introduction of resin concrete compensates for the shortcomings of cement concrete, such as low curing speed, salt damage, and freezethaw characteristics. Finally, examples of implementations and achievements with the developed materials and structures are presented and discussed.
Evolution of kinetics and pore water composition during hydration of a CAC‐Calcite system by addition of Na5P3O10
Authors: Rost Pauline , Schramm Tillmann , Goetz‐Neunhoeffer Friedlinde 
Published: December 2023

AbstractIt was analysed how a low Na5P3O10 (STPP) concentration influences the hydration of a calcium aluminate cement. It is known that the hydration of a CAC‐Calcite system precipitates C2AHX as a precursor phase at 23°C during hydration before the formation of hemi‐ or monocarbonate and the additional formation of CAH10 and AH3. In our study the addition of 0.2 and 1.0 wt.% STPP (bwoc) to a CAC‐Calcite system at 23 °C and with a w/b of 0.33 was investigated and is compared with mixes without STPP addition. Heat flow calorimetry data showed that STPP accelerates the main reaction. Moreover, an additional heat flow event within the first 30 minutes was detected by STPP addition. However, from the results of QXRD analysis, crystalline hydrate phases are formed only during the main reaction. These are CAH10, C2AHX, AH3, hemicarbonate and monocarbonate. STPP shows an influence on the amount of crystalline C2AHX, otherwise, no difference in the qualitative phase content is observed. Gillmore‐Needle‐Testing (IMETER device) could observe an accelerated hardness development during the early heat flow event despite initially reduced viscosity. Pore water studies and thermodynamic modelling (PhreeqC) indicate the formation of an amorphous C‐P‐H phase during this early heat flow event.
Silicate and Portland cement based compositions for protection against electrical corrosion
Authors: Plugin Andrii , Borziak Olga , Pluhin Oleksii , Krykun Oksana , Zhuravel Vitalii 
Published: December 2023

AbstractConductive silicate compositions and compositions based on Portland cement for screen protection against electrical corrosion of reinforced concrete structures and buildings on electrified direct current railways are theoretically and experimentally substantiated. The compositions are used as putty or plaster on structures to be protected. The resulting coating drains corrosive leakage currents from the rails through grounding. In these compositions, the component that provides electrical conductivity is dispersed graphite. Depending on the additional requirements for the coating, sodium silicate with sodium silicon fluoride or Portland cement are used as binders. It was established that in these compositions the silicate and cement components are conductors of the second kind, and graphite is the conductor of the first kind. Due to the imposition of an electric potential, the surfaces of dispersed graphite particles are divided into cathodic areas and anodic areas, where the graphite dissolves, therefore the resource of the composition is determined by the amount of electricity passed through. In addition, it was found that the electrophysical properties of the compositions are in antagonism with their rheological, physical‐mechanical, hydro physical properties, therefore, the development of their composition should be carried out by methods of compromise optimization. Formulations of compositions that have been tested in operational conditions have been developed.
Biofilmfassaden: Begrünung von Beton auf der Mikroskala
Authors: Stohl Leonie , Manninger Tanja , von Werder Julia 
Published: December 2023

KurzfassungDie Klimakrise führt zu einer steigenden Nachfrage nach ökologisch orientierten Konzepten. Dazu gehören im Baubereich nicht nur umweltfreundliche Materialien, sondern auch die Begrünung städtischer Gebiete.Vor diesem Hintergrund wird ein Projekt vorgestellt, dass eine Fassadenbegrünung mithilfe von mikrobiellen Organismen wie Algen statt höheren Pflanzen realisieren will. Die Entwicklung von sogenannten biorezeptiven Materialien ist eine Herausforderung, weil es aktuell noch keine standardisierten Methoden zur Bestimmung der Biorezeptivität gibt. Um ein grundlegendes Verständnis für die Prozesse und Interaktionen zwischen Organismen und Substrat zu gewinnen, werden Betonplatten unterschiedlich strukturiert und ihre Oberflächencharakteristiken dokumentiert. Anschließend werden die Platten unter verschiedensten Bedingungen bewittert und auf ihre Biorezeptivität untersucht. Von besonderem Interesse sind hierbei Einfluss der materialintrinsischen Oberflächenparameter sowie der Umwelt. Langfristig wird geplant ein geeignetes Messkonzept vorzuschlagen, das Materialwissenschaft und Biologie verbindet und verlässliche Vorhersagen zur Biorezeptivität eines Materials treffen kann. In der vorliegenden Arbeit liegt der Schwerpunkt auf dem theoretischen Ansatz und der Versuchsplanung.
Thermodynamic Modeling of Sulfuric and Acetic Acid Attack on Hardened Cement Paste: Effect of Silica Fume
Authors: Berger Felix , Ukrainczyk Neven , Bogner Andreas , Hirsch Astrid , Dehn Frank , Koenders Eduardus 
Published: December 2023

AbstractThe exposure of concrete structures to acid attack is a growing concern. This study employs thermodynamic modeling to investigate the changes in phase assemblage of powdered cement pastes subjected to a wide range of sulfuric and acetic acid concentrations. A modeling approach utilizing IPHREEQC implemented through Matlab is presented, and the obtained results are compared with pH measurements and compositions of equilibrated calcium and sulfate solutions. The influence of incorporating 11% silica fume (SF) as a replacement for cement predicted a 70% reduction of Portlandite content in the hardened cement paste. Consequently, the acid attack processes and subsequent pH reduction are affected. The modeling approach demonstrates good agreement with experimental data for acetic acid, across a broad range of acid concentrations, for both Portland cement and a blend with SF, without the need for any fitting parameters. However, significant discrepancies between the model and experiments are observed in the case of sulfuric acid. This discrepancy arises due to the formation of lump pieces of material in the experimental setup at higher acid concentrations. These lumps consist of a thin layer of altered hardened cement paste, primarily composed of sulfate‐rich phases, encapsulating unaltered hardened cement paste. Since the reaction was not homogeneous and the powder did not entirely react, the sulfuric attack experimental setup was not representative for validating the thermodynamic model.
Zerstörungsfreie Messung der Carbonatisierungstiefe mittels einseitiger Wasserstoffkernspinresonanz
Authors: Glawe Clarissa , Raupach Michael 
Published: December 2023

KurzfassungDie Carbonatisierung von Beton und der damit einhergehende Verlust der Passivierung der Stahlbewehrung stellt jeher eine Herausforderung hinsichtlich der Dauerhaftigkeit von Stahlbetonbauwerken dar. Um eine Schädigung infolge der Korrosion der Bewehrung zu vermeiden und Instandsetzungsmaßnahmen zum Erhalt der Passivierung rechtzeitig durchzuführen, gilt es die Carbonatisierungstiefe des Betons zu bestimmen. Die Bestimmung der Carbonatisierungstiefe mithilfe des pH‐Indikators Phenolphthalein stellt diesbezüglich den Stand der Technik dar, wird hierbei jedoch nur indirekt die Carbonatisierung des Betons auf Grundlage des pH‐Werts bestimmt. Eine direkte Messung der mit der Carbonatisierung einhergehenden strukturellen Änderungen, welche ebenfalls eine Änderung der Transporteigenschaften des Betons hervorruft, wird mithilfe des Phenolphthaleintests nicht erfasst. Mithilfe der einseitigen Wasserstoffkernspinresonanz (1H NMR) ist eine tiefenabhängige Untersuchung der Gefügestruktur möglich. Erste Ergebnisse zeigen, dass eine Ableitung des Carbonatisierungsfortschritts anhand der NMR‐Untersuchungen an Mörtel möglich ist. Mithilfe der Korrelation weiterer Untersuchungsmethoden kann ein umfassendes Verständnis des Carbonatisierungsprozesses gewonnen werden.
Einfluss der Permeation auf die Carbonatisierung von Beton
Authors: Grimm Benedikt , Thiel Charlotte , Kränkel Thomas , Gehlen Christoph 
Published: December 2023

KurzfassungDie Carbonatisierung von Beton kann einerseits zu Schäden bei Stahlbetonbauwerken führen, andererseits kann der Beton so CO2 speichern und damit seinen CO2‐Fußabdruck verringern. In diesem Beitrag wird dargestellt, wie eine effiziente Beschleunigung der Carbonatisierung durch Anlegen eines geringen äußeren Drucks erreicht werden kann. Damit wird neben der Diffusion der wesentlich schneller ablaufende Transportmechanismus der Permeation ausgenutzt, der das CO2 tiefer in das Probeninnere transportiert und damit in kurzer Zeit die Bestimmung des Carbonatisierungswiderstand zementgebundener Materialien ermöglicht. Hierzu wurde eine Prüfeinrichtung entwickelt, die es ermöglicht, die CO2‐Konzentration und in gewissen Grenzen auch relative Luftfeuchte sowie die Temperatur gezielt einzustellen und zu steuern, um so Mörtel‐ und Betonproben schnell und präzise zu carbonatisieren. Der Einfluss verschiedener Druckstufen und Wechselzyklen wird dargelegt und die resultierenden chemischen und physikalischen Veränderungen der Proben bestimmt. Als besonders effizient und gleichzeitig realitätsnah erwies sich die konstante CO2‐Beaufschlagung mit 3 Vol.‐% CO2 mit zusätzlichem, moderatem Gasdruck. Das hier entwickelte Verfahren kann daher genutzt werden, um Betone schnell und effizient in zeitraffenden Materialtests hinsichtlich Carbonatisierungswiderstand zu charakterisieren.
Modelling the hydration of cement ‐ Does chemical shrinkage influence autogenous self‐healing?
Authors: Lahmann Daniel , Keßler Sylvia 
Published: December 2023

AbstractAutogenous self‐healing of cracks in water retaining concrete structures is included in Eurocode 1992‐3 as a possible measure to heal cracks up to a width of 200 μm without additional repair. Water flow through the crack leads to the closure of the fracture, mainly due to CaCO3 precipitation. However, despite standardization, the healing effect seems to be random in practice. This study uses thermodynamic modelling of cement hydration to examine how the timing of crack formation affects crack widening or closure due to chemical shrinkage or swelling and discusses the implications for autogenous self‐healing. It is found that the exact timing of early‐age crack formation can lead to crack widening or closure in the range of a few micrometres. This effect is most prominent for cracking within the first two days of curing and dependents on the cement type, the fraction of inert material in the mix design and the amount of shrinkage that translates into a macroscopic volume reduction. However, it is concluded that other more dominant factors must be at play leading to the discrepancy between laboratory results and the unpredictable healing efficiency observed in practice.
Erhöhung des Carbonatisierungswiderstandes klinkerreduzierter Betone durch alkalische Puffer
Authors: Müller Matthias , Sowoidnich Thomas , Lieboldt Matthias , Kraft Bettina I. E. , Ludwig Horst‐Michael 
Published: December 2023

AbstractIm Stahlbeton kann die Carbonatisierung der Betonrandzone dazu führen, dass die Passivierung des Betonstahls verloren geht, wodurch eine Stahlkorrosion eintreten kann. In Betonen mit puzzolanischen Stoffen, wie beispielsweise calcinierten Tonen, kann die Verringerung des Calciumhydroxidgehaltes im Beton infolge der puzzolanischen Reaktion zu einer Erhöhung der Carbonatisierungsneigung führen. Dies ist ein maßgeblicher begrenzender Faktor für die im Beton anwendbaren Einsatzmengen an calcinierten Tonen.Daher wurde an Mörteln untersucht, ob durch eine Erhöhung des Calciumhydroxidpuffers auch eine Verbesserung des Carbonatisierungswiderstandes möglich ist. Die grundsätzliche Eignung dieses Ansatzes konnte bestätigt werden. Dies sollte es ermöglichen, die Klinkeraustauschrate durch calcinierten Ton zu erhöhen, ohne zu einer gravierenden Beeinträchtigung der Betondauerhaftigkeit zu führen.
A pseudo‐Double‐Network Hydrogel Built upon Layered Double Hydroxides with Self‐Strengthening Properties
Authors: Diao Shu‐Jing , Lin Chang‐Gen , Zhang Jie , Zhang Fen‐Di , Chu Jin‐Feng , Song Yu‐Fei 
Published: December 2023

AbstractWhile great achievements have been made in the development of mechanically robust nanocomposite hydrogels, incorporating multiple interactions on the bases of two demensional inorganic cross‐linkers to construct self‐strengthening hydrogels has rarely been investigated. To this end, we propose here a new method for the coupling the dynamic covalent bonds and non‐covalent interactions within a pseudo double‐network system. The pseudo first network, formed through the Schiff Base reation between Tris‐modified layered double hydroxides (Tris−LDHs) and oxidized dextran (ODex), is linked to the second network built upon non‐covalent interactions between Tris−LDHs and poly(acrylamide‐co‐2‐acrylamido‐2‐methyl−propanesulfonate) (p‐(AM‐co‐AMPS). The swelling and mechanical properties of the resulting hydrogels have been investigated as a function of the ODex and AMPS contents. The as‐prepared hydrogel can swell to 420 times of its original size and retain more than 99.9 wt.% of water. Mechanical tests show that the hydrogel can bear 90 % of compression and is able to be stretched to near 30 times of its original length. Cyclic tensile tests reveal that the hydrogels are capable of self‐strengthening after mechanical training. The unique energy dissipation mechanism based on the dynamic covalent and non‐covalent interactions is considered to be responsible for the outstanding swelling and mechanical performances.
Polyhedral Oligomeric Silsesquioxane D3h‐(RSiO1.5)14
Authors: Hunsicker Marc , Ankur  , Morgenstern Bernd , Zimmer Michael , Scheschkewitz David 
Published: December 2023

AbstractWhile smaller polyhedral oligomeric silsesquioxanes TnRn (POSS) are readily accessible or even commercially available, unambiguously authenticated larger systems (n>12) have barely been reported. Synthesis and isolation procedures are lengthy, and yields are often very low. Herein, we present the surprisingly straightforward and high‐yielding access to the phenyl‐substituted derivative of a so far only postulated second D3h‐symmetric T14 isomer and with that the largest crystallographically characterized POSS cage with organic substituents. Treatment of the commercially available incompletely condensed T7Ph7(OH)3 silsesquioxane with catalytic amounts of trifluoromethanesulfonic acid results in high yields of the T14Ph14 framework, which is isolated in crystalline form by a simple work‐up. D3h‐T14Ph14 was analyzed by single crystal X‐ray diffraction, multinuclear NMR spectroscopy and thermal analysis. The relative energies of all four theoretically possible T14Ph14 isomers were determined by optimization of the corresponding structure using DFT methods.
Resolution of trans‐1,2‐cyclohexanedicarboxylic acid containing two carboxylic groups by forming diastereomeric salts based on feeding molar ratio control
Authors: Xin Xiaoyu , Zhou Junjie , He Quan , Peng Yangfeng , Wei Yongming , Zhao Hongliang , Tong Tianzhong 
Published: December 2023

AbstractTo investigate the thermodynamic and molecular self‐assembly mechanism of trans‐1,2‐cyclohexane dicarboxylic acid containing two carboxylic acid groups in the chiral resolution process, (S)‐phenylethylamine was used as the chiral resolving agent. Two stoichiometric salts were formed when the raw materials were fed at different molar ratios: cyclohexane dicarboxylate monophenylethylamine salt and cyclohexane dicarboxylate diphenylethylamine salt. When the molar ratio of the (S)‐phenylethylamine to trans‐1,2‐cyclohexane dicarboxylic acid was less than 3:1, trans‐(1S,2S)‐cyclohexane dicarboxylic acid was obtained with 97 e.e% purity. But when the molar ratio exceeded 3:1, the product was the racemic trans‐(1,2)‐cyclohexane dicarboxylic acid. In addition, single crystal structures of more soluble mono‐salt, less soluble mono‐salt, and less soluble di‐salt were obtained. The weak intermolecular interactions and the way of the molecules packing in the crystals were analyzed. The hydrogen bond was stronger in the less soluble salt than that in the more soluble salt. And a “lock‐and‐key” structure in the hydrophobic layers makes it more tightly packed through the van der Waals interaction, which is responsible for the stability of less soluble salts.
Gas pressure dependence of optical and mechanical properties in a SiCO thin film for optical waveguide by reactive sputtering method
Authors: Nikkuni Hiroyuki , Ito Hiroshi , Takatsuka Yu 
Published: December 2023

AbstractIn this study, the gas pressure dependence of optical and mechanical characteristics in reactive sputtered SiCO thin films for optical guided‐wave pressure sensors was experimentally investigated. Thin films were fabricated by varying the gas pressure from 0.3 to 1.0 Pa at an oxygen flow ratio of 6%, and the gas pressure dependences was clarified. As the gas pressure increased, the optical bandgap of the SiCO thin film increased, resulting in a transparent SiCO films. On the other hand, the refractive index, young's modulus, and hardness decreased with increasing gas pressure. Combining this dependence with the oxygen inflow ratio dependence of the previous study, the first‐order approximation formula for the gas pressure and oxygen flow rate ratio for various film characteristics was obtained. Based on this equation, trajectories of equal bandgaps and equal young's moduli on the oxygen flow ratio—gas pressure plane were created on the oxygen influx ratio‐gas pressure coordinates, making it easy to fabricate waveguides with desired characteristics.
Three‐Component Reactions of 2,2,2‐Trifluoroethyl Ketones, Aryl Azides and Aqueous Ammonia for the Synthesis of 4‐Cyano‐1,2,3‐triazoles
Authors: Gao Ge , Lv Leiyang , Li Zhiping 
Published: December 2023

AbstractA new method for the synthesis of 4‐cyano‐1,2,3‐triazoles is developed using a three‐component strategy. The cyano group is generated in situ by the reaction of 2,2,2‐trifluoroethyl ketone and aqueous ammonia. The one‐pot protocol allows the synthesis of 4‐cyano‐1,2,3‐triazoles under mild reaction conditions.
Assessment of relative tectonic activity in the Lar region, Zagros Fold‐Thrust Belt, SW Iran: Insights from geomorphometric analysis
Authors: Zarei Elham , Faghih Ali , Soleimani Masoumeh , Zarei Saeed 
Published: December 2023

AbstractThe Zagros Fold‐Thrust Belt is a tectonically active region within the Alpine‐Himalayan orogenic system resulting from ongoing convergence between Afro‐Arabian and Central Iranian plates. The presence of various geomorphic features in this region provides an ideal natural case for identifying deformed landforms resulting from active tectonics. The relative tectonic activity along the Lar and Didehban faults within the Zagros Fold‐Thrust Belt, SW Iran was evaluated using six DEM‐derived geomorphic indices: the stream‐gradient index (SL), drainage basin asymmetry (AF), hypsometric integral (HI), valley floor width‐valley height ratio (Vf), drainage basin shape (Bs), and mountain‐front sinuosity (Smf). These indices were combined to yield the relative active tectonics index (Iat) that allows the variation of tectonic activity along the Lar and Didehban faults to be related to variations in rates of incision, tectonic tilting and uplift. This variable tectonic activity was characterized by different Iat values along the faults. The low to high relative tectonic activity (class 1: 1 < Iat < 1.5, class 2: 1.5 < Iat < 2, class 3: 2 < Iat < 2.5, class 4: 2.5 < Iat) correlates with variable geomorphic features along the faults. The results of this study present an approach for assessing the effects of active tectonics and also for sustainable land use planning over a large area.