An experimental approach based on the study of the pore solution of metakaolin-based geopolymer has been established in this study to investigate the phenomenon of carbonation in these materials. The ...results obtained showed a very fast decrease in the pH, compared to Portland cement, and an almost total carbonation of the pore solution in natural condition after only 14days. In natural CO2 conditions, the formation of sodium carbonate did not lead to a decrease of pH below 10.5 at one year, thus limiting the risk of corrosion by depassivation of the reinforcement. Accelerated carbonation performed under 50% of CO2 highlighted the formation of large amounts of sodium bicarbonate responsible for a lower pH of the pore solution, and a potential risk of corrosion by carbonation. That result also demonstrated that the accelerated carbonation tests made for Portland cement are not representative of the natural reaction in geopolymer cases.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Dieses Open-Access-Handbuch versteht sich als praktisches Hilfsmittel für den gezielten Einsatz eines automatisierten ÖPNV auf dem Weg zur Mobilitätswende. Es richtet sich in erster Linie an ...Entscheidungsträger, Verwaltungen kleinerer und größerer Kommunen sowie an Verkehrsbetriebe. Das Handbuch vermittelt der Leserin und dem Leser einen umfassenden Überblick über verschiedene Entwicklungslinien des automatisierten Fahrens sowie über die damit verbundenen Chancen und Risiken für Mobilität und Gesellschaft. Die Autorinnen und Autoren verdeutlichen sehr anschaulich, dass die Chancen des automatisierten Fahrens vor allem in der Ergänzung oder Erweiterung des ÖPNV liegen. Davon ausgehend adressiert das Buch sehr praxisnah und umsetzungsorientiert alle wesentlichen Fragestellungen, die vor dem Start eines Pilotprojekts zur Einführung eines automatisierten ÖPNV bedacht werden sollten. Der Fokus liegt auf den oft unberücksichtigten ländlichen Räumen bzw. jenen Räumen größerer Städte und Regionen, die heute von den Verkehrsbetrieben und -verbünden nicht oder nur sehr unzureichend versorgt werden. Den Herausgebern und der Herausgeberin ist das Anliegen, die Mobilitätswende so gut und rasch als möglich zu schaffen, sowie das Wissen um die herausragende Rolle des ÖPNV als kollektives Verkehrsmittel gemein. Die Autorinnen und Autoren stammen aus der Wissenschaft und aus der täglichen Planungs- und Beratungspraxis. Es ist ihnen in hervorragender Weise gelungen, eine sowohl systemische wie auch sehr lösungsorientierte Sicht auf die oft komplexe Aufgabe der Mobilitätswende zu eröffnen und die Rolle zu beschreiben, die ein automatisierter ÖPNV bei der Mobilitätswende spielen könnte.
Within the scope of the present work, extensive experimental and numerical investigations are carried out on the crack propagation behaviour in steel plates under cyclic loading, which have been ...reinforced with adhesively bonded CFRP lamellas, as well as on the load-bearing and failure behaviour of CFRP-steel double-lap joints. Based on the results, a fracture mechanics engineering procedure for estimating the remaining service life of CFRP-reinforced steel plates is developed and validated.
•Eco-friendly CSA cement is introduced to the valorization of sediments in road.•Compare the compaction and mechanical properties of OPC/CSA solidified sediments.•Establish the prediction models ...among the qc, qit, and E of solidified sediments.
Stabilization/solidification (S/S) of dredged sediments is an environmentally friendly, low-cost and time-efficient way to manage this waste (according to the European waste classification) in the context of valorization as novel resources. In this study, the main objective was to evaluate the efficiency of using a novel and green binder Calcium Sulfo-Aluminate (CSA) cement to solidified Dunkirk sediments. For comparison, the Ordinary Portland Cement (OPC) binder was used as a reference. For this purpose, several tests were performed on samples containing various types and amounts of binders. The experimental program included: modified Proctor compaction tests, immediate Californian Bearing Ratio (I-CBR) index tests, unconfined compressive strength tests, splitting tensile strength tests, measurements of elastic and secant modulus, and mineral and micropore structure analysis. It is realistic to conclude that the compaction performance of the CSA-/OPC-solidified sediments is significantly improves. The mechanical performance of compressive, tensile strength and elastic modulus increases with binder content and curing time. The simple model obtained to relate the compressive and tensile strength with elastic modulus allows predicting easily, for a given suitable set of characteristics, the type or the amount of binder needed. This model allows optimizing the amount of binder to reach a given properties of solidified sediments and hence improves the cost of developed material. The results also demonstrate the ability of solidified sediment to be valorized in road construction.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Smart materials are kinds of designed materials whose properties are controllable with the application of external stimuli such as the magnetic field, electric field, stress, and heat. Smart ...materials whose rheological properties are controlled by externally applied magnetic field are known as magneto-rheological materials. Magneto-rheological materials actively used for engineering applications include fluids, foams, grease, elastomers, and plastomers. In the last two decades, magneto-rheological materials have gained great attention of researchers significantly because of their salient controllable properties and potential applications to various fields such as automotive industry, civil environment, and military sector. This article offers a recent progressive review on the magneto-rheological materials technology, especially focusing on numerous application devices and systems utilizing magneto-rheological materials. Conceivable limitations, challenges, and comparable advantages of applying these magneto-rheological materials in various sectors are analyzed critically, which provides a clear pathway to the researchers in selecting and utilizing these materials. The review starts with an introduction to the elementary description of magneto-rheological materials and their significant contribution in various fields. Following this, different types of the magneto-rheological materials, modeling of the magneto-rheological materials, magneto-rheological material–based devices, and their applications have been extensively reviewed to promote practical use of magneto-rheological materials in a wide spectrum of the application from the automobile to medical device.
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NUK, OILJ, SAZU, UKNU, UL, UM, UPUK
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