Dokument-ID Dokumenttyp Autoren/innen Persönliche Herausgeber/innen Haupttitel Abstract Auflage Verlagsort Verlag Herausgeber (Institution) Erscheinungsjahr Titel des übergeordneten Werkes Jahrgang/Band ISBN Veranstaltung Veranstaltungsort Beginndatum der Veranstaltung Enddatum der Veranstaltung Ausgabe/Heft Erste Seite Letzte Seite URN DOI Lizenz Datum der Freischaltung OPUS4-27756 Beitrag zu einem Tagungsband Akindahunsi, A. A.; Schmidt, Wolfram; Uzoegbo, H.C.; Iyuke, S.E. Uzoegbo, H.C.; Schmidt, Wolfram The influence of starches on some properties of concrete Starches and its derivatives are known to exhibit viscosity modifying characteristics. In an ongoing work, the influence of com and cassava starches on some properties of concrete such as compressive strength, heat of hydration and creep are examined. Various percentages (0.0, 0.5, 1.0, 1.5 and 2 %) of starches by weight of cement were added to concrete mixes prepared in the laboratory. Preliminary results of compressive strengths showed that both starches have some positive impact (e.g. there was 5.3 % increase in strength due to a 1 % addition of com starch by weight of cement in comparison to the control while cassava starch of the same percentage gave 4.9 % increase in strength) at certain percentages of starch addition to concrete at 28 days. The creep and hydration results shows the starch additions compares well and in some instance performs better. Bundesanstalt für Materialforschung und -prüfung (BAM) 2013 ACCTA - International conference on advances in cement and concrete technology in Africa 2013 (Proceedings) 978-3-9815360-3-4 ACCTA - International conference on advances in cement and concrete technology in Africa 2013 Johannesburg, South Africa 28.01.2013 30.01.2013 637 645 2016-02-20 OPUS4-36880 Beitrag zu einem Tagungsband Akindahunsi, A. A.; Uzoegbo, H. Ch.; Schmidt, Wolfram Schmidt, Wolfram; Priebe, Nsesheye Susan Effect of Cassava Starch on Shrinkage Characteristics of Concrete The use of starch and its derivatives in concrete as an admixture to modify relevant properties of concrete is on the increase in recent times. It is known to modify the rheology, to affect the hydration kinetics of cement, and influence on initial and final setting time of cement. This paper examines the effect of cassava starch on concrete. shrinkage properties of concrete, with and without starch addition, were studied. Various percentages (0, 0.5, 1.0, 1.5 and 2 %) of starches by weight of cement were added to concrete mixes prepared in the laboratory. Shrinkage tests were conducted for duration of up to one year. The result show that concretes with starch additions exhibit lower shrinkage, which is an indication the addition of starch as admixture in concrete improves the ability of the concrete reduce shrinkage problems. Berlin Bundesanstalt für Materialforschung und -prüfung (BAM) BAM 2016 Advances in Cement and Concrete Technology in Africa 187 978-3-9817502-3-2 2nd International Conference on Advances in Cement and Concrete Technology in Africa Dar es Salaam, Tanzania 27.01.2016 29.01.2016 196 2016-07-18 OPUS4-27271 Beitrag zu einem Tagungsband Barthel, Maria; Kühne, Hans-Carsten; Schmidt, Wolfram Bager, D. H.; Silfwerbrand, J. Multilayer concrete pavers - solutions for the mitigation of the urban heat island effect The large scale application of self-cooling concrete pavers is a future-oriented approach to reduce the urban heat island effect in inner-city areas. Making use of evaporation enthalpy, these new pavements counterbalance the absorption of solar radiation and the subsequent transfer of heat to the surrounding environment. The concrete pavers consist of a permeable top-layer and a storage layer. As the different requirements of these layers demand different concrete mixtures they are developed and optimised for their respective functions. This paper presents some results of the concrete mixture design and Solutions that combine a sufficient compressive strength as well as good water transportation properties for the face concrete layer. Stockholm Royal Institute of Technology International Federation for Structural Concrete 2012 fib Symposium Stockholm 2012 'Concrete structures for a sustainable community' (Proceedings) 978-91-980098-1-1 fib Symposium Stockholm 2012 'Concrete structures for a sustainable community' Stockholm, Sweden 11.06.2012 14.06.2012 513 516 2016-02-20 OPUS4-27769 Beitrag zu einem Tagungsband Barthel, Maria; Schmidt, Wolfram; Kühne, Hans-Carsten Uzoegbo, H.C.; Schmidt, Wolfram Concrete pavers for the mitigation of the urban heat island effect Bundesanstalt für Materialforschung und -prüfung (BAM) 2013 ACCTA - International conference on advances in cement and concrete technology in Africa 2013 (Proceedings) 978-3-9815360-3-4 ACCTA - International conference on advances in cement and concrete technology in Africa 2013 Johannesburg, South Africa 2013-01-28 2013-01-30 953 960 2016-02-20 OPUS4-26545 Beitrag zu einem Tagungsband Barthel, Maria; Schmidt, Wolfram; Kühne, Hans-Carsten Betontechnologische Ansätze zur Vermeidung innerstädtischer Hitzeinseln Die Versiegelung von Oberflächen, Bebauung und die Ausweitung städtischer Gebiete führen weltweit besonders in sonnenreichen Regionen zu innerstädtischen Hitzeinseln. Diese Flächen wirken als Wärmespeicher, so dass an Sonnentagen eine Temperaturdifferenz bis zu 10 K zwischen Stadt und umliegendem Land entstehen kann. Verstärkt wird dieser sogenannte Urban Heat Island Effect (UHIE) durch die meist direkte Abführung des anfallenden Regenwassers in die Kanalisation, wodurch eine Kühlung durch stetige Verdunstung unterbunden ist, Mit steigender Urbanisierung wächst auch die Bedeutung dieses Phänomens. Innerstädtische Hitzeinseln ziehen direkte wirtschaftliche und soziale Folgen nach sich, da hohe Temperaturen eine teure Klimatisierung der Städte bedingen. So entsteht ein erhöhter Verbrauch an Ressourcen sowie zusätzliche Abwärme. Das Wohlbefinden und die Gesundheit der Bevölkerung verschlechtern sich bei sehr hohen Temperaturen, was zu sinkender Leistungsfähigkeit und sogar zu einer erhöhten Sterberate führen kann. F.A. Finger - Institut für Baustoffkunde / Bauhaus-Universität Weimar 2012 18. Ibausil - Internationale Baustofftagung 2 978-3-00-034075-8 18. Ibausil - Internationale Baustofftagung Weimar, Germany 12.09.2012 15.09.2012 3.07 2-0042 2-0050 2016-02-19 OPUS4-29931 Zeitschriftenartikel Barthel, Maria; Schmidt, Wolfram; Kühne, Hans-Carsten Mitigation of the urban heat island effect by self-cooling concrete pavers Worldwide an increasing migration from rural to urban regions can be observed. Hence cities are growing and as a result the building density and the land sealing rise. Concrete as commonly used building material in urban structures provides a high heat storage capacity. Therefore the microclimate in cities has become warmer than in the surrounding areas. This phenomenon is called Urban Heat Island Effect. To mitigate this situation a large scale application of self-cooling concrete pavers is an approach to reduce the urban heat island effect. Making use of evaporation enthalpy, this new type of pavements counterbalances the absorption of solar radiation and the subsequent transfer of heat to the surrounding environment. The typical double-layer structure of concrete paving stones can be maintained. The mass concrete acts as a water storage layer and is covered by a permeable face concrete. As the different requirements of these layers demand different concrete mixtures, they are developed and optimised for their respective functions. This paper presents some suitable no-slump concrete mixtures that combine a sufficient compressive strength as well as good water transportation properties for the above mentioned approach. New York, NY, USA International Institute for Conservation of Historic and Artistic Works 2013 Civil and environmental research 4 35 39 2016-02-20 OPUS4-25182 Beitrag zu einem Tagungsband Barthel, Maria; Schmidt, Wolfram; Kühne, Hans-Carsten; Meng, Birgit Rogge, A.; Meng, B. Betonpflastersteine mit erweiterten Leistungsmerkmalen Berlin BAM Bundesanstalt für Materialforschung und -prüfung Deutscher Ausschuss für Stahlbeton e.V. (DAfStb) 2011 52. DAfStb-Forschungskolloquium 978-3-9814281-0-0 52. DAfStb-Forschungskolloquium Berlin, Deutschland 2011-11-07 2011-11-08 194 203 2016-02-19 OPUS4-36877 Beitrag zu einem Tagungsband Barthel, Maria; Schmidt, Wolfram; Kühne, Hans-Carsten; Rübner, Katrin Schmidt, Wolfram; Priebe, Nsesheye Susan Interactions between waste paper sludge ashes and superplasticizers based on polycarboxylates In many industrial nations, about two third of the paper demand is covered by recovered paper. A major process step within the treatment of waste paper is the de-inking. It is a floating process yielding paper sludge as a waste product. About 50 % of this residue is used as a fuel. In several cases it is burnt at temperature of about 850 °C and thereafter the accrued ashes are collected in the flue gas filter. During the combustion, kaolinite and calcium oxide generate gehlenite and larnite. Calcite is the main component of waste paper sludge ash (PA).The chemical and mineralogical composition of PA suggests using it as a supplementary cementitious material. In modern construction materials technology, workability aspects gain importance, since for most modern materials the rheology and compaction ability are relevant for the operation at a hardened state. It was observed that PA significantly increases the water demand of powder systems, which can cause serious problems during the casting of mineral binder systems containing PA. It is therefore obvious that binder systems containing PA might demand for the use of superplasticizers. Superplasticizers are polymers with anionic backbone that cause electrostatic and steric repulsion effects upon adsorption on surfaces of particles and hydration phases. In this paper interactions between superplasticizers and waste paper sludge ashes are discussed and analysed. Based on observations of changes in the zeta potential and the dispersion of the particle system, the influence of the charge density of superplasticizers is observed and time dependent effects are demonstrated. Berlin Bundesanstalt für Materialforschung und -prüfung (BAM) BAM 2016 Advances in Cement and Concrete Technology in Africa 978-3-9817502-3-2 2nd International Conference on Advances in Cement and Concrete Technology in Africa Dar es Salaam, Tanzania 27.01.2016 29.01.2016 181 186 2016-07-18 OPUS4-35741 Zeitschriftenartikel Barthel, Maria; Vogler, Nico; Schmidt, Wolfram; Kühne, Hans-Carsten Outdoor performance tests of self-cooling concrete paving stones for the mitigation of urban heat island effect Rising temperatures worldwide pose an increasing challenge for safe and healthy living conditions. Particularly inner cities have been affected by these environmental changes because of the materials used to build houses, streets and infrastructure. The most common building material is concrete. It shows a specific heat capacity, while the heat conductivity for Standard concrete is low. Thus, the use of concrete generates a high capacity of heat storage. In addition, extensive soil sealing also contributes to the temperature rise of inner city areas compared to their surroundings. To mitigate this so-called urban heat island effect, a self-cooling concrete paver was developed. This paver is able to store water. The evaporation of the water at elevated temperatures provides a cooling effect. This paper focuses on determination of this new paver's capability to cool the surface and the surrounding. The new paver's cooling Qualities were analysed in a series of laboratory tests. To prove the results outside of laboratory conditions, two fields (12 m × 8 m) with self-cooling and reference pavers were installed in Spain. This paper presents and discusses the results of the tests. Correlation between reduced surface temperature of the self-cooling concrete pavers and the air temperature is examined. 2017 Road Materials and Pavement Design 18 2 453 463 10.1080/14680629.2016.1163282 2016-04-18 OPUS4-48483 Beitrag zu einem Tagungsband Barucker-Sturzenbecher, Meike; Schmidt, Wolfram Schmidt, Wolfram Learning from the future - How children of Mukuru fancy the city of tomorrow Sustainability means meeting the needs of today without compromising the needs of the next generations. How can we meet the needs of the next generations, if we do not even know what these needs are? If we do not listen to the next generation and learn from them? Do we even meet the needs of today for everyone on earth? Berlin Bundesanstalt für Materialforschung und -prüfung (BAM) 2019 ISEE Africa - Innovation, Science, Engineering, Education 978-3-9818564-2-2 ISEE Africa - Innovation, Science, Engineering, Education Nairobi, Kenya 30.01.2019 01.02.2019 194 197 urn:nbn:de:kobv:b43-484832 https://creativecommons.org/licenses/by-nc-nd/4.0/deed.de 2019-07-24