TY - JOUR A1 - Schmidt, Wolfram A1 - Ramge, Peter A1 - Kühne, Hans-Carsten T1 - Einfluss der Lagerungsbedingungen von Zement auf die Verarbeitungs- und Erhärtungseigenschaften von Beton = Effect of the storage conditions of cement on the processing and hardening properties of concrete N2 - In Produktionspausen können in Betonwerken nennenswerte Lagerungsintervalle entstehen. Auf Baustellen und in den Instandsetzungen werden Zement- und Trockenmörtelsäcke teilweise über längere Zeiträume gelagert. Auch im Zusammenhang mit Zementimporten und zunehmend filigran abgestimmten Betonrezepturen die bereits bei kleinen Änderungen der Ausgangsstoffe sensibel reagieren, nimmt die Relevanz der Zementlagerung zu. Aus diesem Grund wurde der Einfluss der Zementlagerung auf die Eigenschaften von Betonen in einer Versuchsreihe an der Bundesanstalt für Materialforschung und -prüfung (BAM) ermittelt. KW - Alterung KW - Zement KW - Sulfationengehalt KW - C3A KW - Rheologie KW - Ageing KW - Cement KW - Sulphate ion content KW - Rheology PY - 2009 SN - 0373-4331 SN - 1865-6528 N1 - Sprachen: Deutsch/Englisch - Languages: German/English VL - 75 IS - 6 SP - 10 EP - 17 PB - Bauverl. CY - Gütersloh AN - OPUS4-19747 LA - mul AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schmidt, Wolfram T1 - Challenges of the African environmental conditions for concrete mixture composition N2 - Concrete technology was exposed to a rapid development during the last three decades. For the longest time in its history, concrete was considered as a three component System consisting of aggregates, which are bound by the hardened cement paste consisting of hydrated cement. Traditionally, the only way of adjusting the consistency of concrete was using well adjusted aggregates and grading curves and adding excess water to the concrete, accepting that the latter in return reduces strength and durability. During the last three decades, however, concrete has developed further from a three component System towards an (at least) five component system, since the use of mineral additions and Chemical admixtures has become state of the art. Both components are able to enhance the workability, the compactability, and the density of the microstructure with effects on strength, ductility and durability, while cement can be saved in parallel. Due to reasonable use of admixtures and additions, concrete can be designed to match mechanically high performance specifications. Traditionally, cement paste was considered the weakest component in concrete. Flowever, in modern concrete a good paste composition can yield highest performance, passing the role of the mechanical bottleneck towards the aggregates. T2 - Workshop cement and concrete for Africa CY - Berlin, Germany DA - 17.08.2011 KW - Cement KW - Concrete KW - Mixture composition KW - Africa KW - Climatic conditions PY - 2011 SN - 978-3-9814281-4-8 SP - 37 EP - 49 PB - Bundesanstalt für Materialforschung und -prüfung (BAM) CY - Berlin AN - OPUS4-24780 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schmidt, Wolfram A1 - Priebe, Nsesheye Susan A1 - Kühne, Hans-Carsten T1 - Optimising the rheology of concrete for sub-Saharan African boundary conditions / Optimierung der Rheologie von Beton für Rahmenbedingungen in Subsahara-Afrika N2 - Die Zement- und Betontechnologie in Afrika hat keine ähnlich lange Tradition wie viele Länder der nördlichen Hemisphäre. In vielen afrikanischen Ländern ist die Bauindustrie jedoch von Wachstum gekennzeichnet und hier werden Zement und Beton zukünftig zweifelsohne an Bedeutung gewinnen. KW - Africa KW - Cement KW - Concrete KW - Proficiency testing KW - Round robin PY - 2012 SN - 0373-4331 SN - 1865-6528 N1 - Sprachen: Deutsch/Englisch - Languages: German/English N1 - Geburtsname von Priebe, Nsesheye Susan: Msinjili, N. S. - Birth name of Priebe, Nsesheye Susan: Msinjili, N. S. VL - 78 IS - 09 SP - 60 EP - 67 PB - Bauverl. CY - Gütersloh AN - OPUS4-27338 LA - mul AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schmidt, Wolfram A1 - Hirya, N.N.M. A1 - Bjegovic, D. A1 - Uzoegbo, H.C. A1 - Kumaran, S.G. T1 - Cement technology in sub-Saharan Africa-practical and scientific experiences N2 - Sub-Saharan Africa is populated by more than half a billion people, and rapid urbanization is creating challenges in the areas of housing, roads, railways, power supply, dams and water pipelines — aspects of nfrastructure that are critical to the well being of the population. This situation indicates that cement and concrete will play a major role in the future construction technology in Africa, despite the fact that it does not have a long-lasting tradition over most of the continent. Although the continent is rich in natural resources for the production of mineral binder systems, many sub-Saharan African countries exhibit challenging boundary conditions, that have to be well understood in order to use cement and concrete technologies in a sustainable and reasonable way. KW - Africa KW - Cement KW - Technology transfer KW - SPIN PY - 2012 SN - 0002-7812 VL - 91 IS - 5 SP - 52 EP - 56 PB - American Ceramic Society CY - Westerville, Ohio AN - OPUS4-26075 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schmidt, Wolfram A1 - Gluth, Gregor T1 - Knowledge transfer and quality assurance - key factors for the future prospects of building with cement in Africa / Wissentransfer und Qualitätssicherung - Schlüsselfaktoren für die Zukunftsperspektiven der Bauweise mit Zement in Afrika N2 - The SPIN Project included workshops for young academics and building materials laboratories of the cement and concrete sector. Within the framework of the SPIN Project, plans were discussed for the conference 'Advances in Cement and Concrete Technology in Africa' that will take place in January 2013. A lecture on application rules for shotcrete construction was given by Prof. Regina Stratmann-Albert who took part in the courses as guest speaker. A short lecture was given by Akindehinde Ayotunde on the use of starch in cement-bound systems. Renato Rajzer talked about standard regulations for quality assurance during site operation. A workshop for an interlaboratory comparison took place with participants from all regions of Africa to test cement according to the standard series EN 196. The Round Robin test comprises the determination of the tensile bending and compressive strengths according to EN 196-1, of the water demand, the initial and final set, and the soundness according to EN 196-3 as well as of the fineness according to EN 196-6. KW - Africa KW - Cement KW - Concrete KW - Proficiency testing KW - Round robin PY - 2012 SN - 0949-0205 N1 - Sprachen: Deutsch/Englisch - Languages: German/English VL - 65 IS - 9 SP - 34 EP - 38 PB - Bauverl. BV CY - Gütersloh AN - OPUS4-26535 LA - mul AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schmidt, Wolfram T1 - Start of round-robin test for cement testing in Africa T1 - Start für Ringversuch zur Zementprüfung in Afrika N2 - Within the scope of the SPIN project (www.spin.bam.de), three staff members of the Federal Institute for Materials Research and Testing (BAM), Berlin, traveled to Tanzania on 30 June. There they, together with scientists from several other African countries, were to give a course of lectures for Masters and Ph.D. students as well as leading a kick-off workshop for an all-African round-robin test for cement testing. The first stop of the BAM staff was in Zanzibar, where they inspected an on-going a building reinstatement project and discussed plans for the conference “Advances in Cement and Concrete Technology in Africa” (www.accta2013.com) to be held in January 2013. At the international conference in Johannesburg, which is mainly organized by BAM and the University of the Witwatersrand, more than 300 visitors from over 40 nations will come together. KW - Africa KW - Cement KW - Concrete KW - Proficiency testing KW - Round robin PY - 2012 UR - http://www.bft-international.com/de/artikel/bft_2012-08_Start_fuer_Ringversuch_zur_Zementpruefung_in_Afrika_1468912.html SN - 0373-4331 SN - 1865-6528 N1 - Sprachen: Deutsch/Englisch - Languages: German/English VL - 08 SP - 54 EP - 55 PB - Bauverl. CY - Gütersloh AN - OPUS4-26429 LA - mul AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schmidt, Wolfram A1 - Kumaran, G.S. T1 - Clearing the way N2 - With a rapidly-expandingpopuiation plus enormous infrastructure and housing needs, Africa has vast potential for its domestic construction industry. Cement and concrete are expected to play a key role in the region's development but to be truly sustainable current productlon technology will need to be adapted to local boundary conditions. It is in this context that 11 African and European organisations created the Spearhead Network for Innovative, Ctean and Safe Cement and Concrete Technologies (SPIN) which aims to Support the development of concepts tailor-made for Africa. KW - Cement KW - Concrete KW - Africa KW - Research policy PY - 2012 SN - 0959-6038 IS - October SP - 86 EP - 88 PB - Holbrook & Son CY - Dorking AN - OPUS4-27177 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Priebe, Nsesheye Susan A1 - Schmidt, Wolfram A1 - Gluth, Gregor A1 - Florea, M.V.A. A1 - Kumaran, G.S. A1 - Akindahunsi, A. A. A1 - Uzoegbo, H.C. A1 - Oslakovic, I.S. ED - Alexander, M. G. ED - Beushausen, H.-D. ED - Dehn, F. ED - Moyo, P. T1 - Concrete knowledge improvement in sub-Saharan Africa N2 - The building situation in Africa is overwhelmed with high-priced materials and lack of adequate concrete technology, which provides a challenge in the concrete industry. Worldwide, cement and concrete experts are at the cutting-edge to sustainable, green and healthy but nonetheless high-performance concrete, which is more sustainable and safer than traditional methods of construction with clay and wood. Since concrete in Africa is rather a new construction material, this sustainability experience can offer the continent a unique opportunity to begin a constantly growing building sector with the newest state-of-the-art technology. This can be achieved without subordinating to existing standards by establishing a sustainable “African concrete technology”. The major challenge for most sub-Saharan countries is the deficiency of experts, which would be required to establish such state-of-the-art technology. Based on the examples of two African-European scientific networks—SPIN and LightSHIP—this paper presents possible solution strategies for the establishment of a scientific cooperation between Europe and Africa, with links to policy making bodies that can help accelerate the progress of cement and concrete industries in Africa. T2 - 3rd International conference on concrete repair, rehabilitation and retrofitting III CY - Cape Town, South Africa DA - 03.09.2012 KW - Education KW - Research sub-Sahara KW - Africa KW - Cement KW - Concrete PY - 2012 SN - 978-0-415-89952-9 N1 - Geburtsname von Priebe, Nsesheye Susan: Msinjili, N. S. - Birth name of Priebe, Nsesheye Susan: Msinjili, N. S. IS - Theme 5 SP - 1459 EP - 1465 PB - CRC Press CY - London, UK AN - OPUS4-26508 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Uzoegbo, H.C. A1 - Bjegovic, D. A1 - Schmidt, Wolfram A1 - Kitobo, W. T1 - SCM potential in Africa KW - Africa KW - Cement KW - Supplementary cementitious materials PY - 2012 SN - 0263-6050 SN - 0308-8855 IS - August SP - 27 EP - 38 PB - Swan CY - Leatherhead AN - OPUS4-27176 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ramge, Peter A1 - Schmidt, Wolfram A1 - Kühne, Hans-Carsten ED - Uzoegbo, H.C. ED - Schmidt, Wolfram T1 - Effect of the storage of cement on early properties of cementitious systems N2 - As soon as cement is mixed with water, the hydration reaction starts to set of. The progression of the hydration process is governed by the amount and the availability of water and its possibility to access the unhydrated cement grain surfaces. For a total hydration cement theoretically requires water amounting approximately 0.38 of its own mass. Nevertheless, due to the cement’s highly hygroscopic nature, already the moisture in the ambient air can cause first hydration reactions to set in upon the cement grain surfaces. Such pre-hydration processes have an effect on the cement's properties. Dpending on the specific conditions during the storage the significance of the impact on certain properties can vary. If cement is consumed soon after production and is transported only short distances in a silo wagon to its final destination for immediate use without further stock transfer, the effects are rather negligible. However, if cement is delivered in bags, transported over long distances, shifted serval times and stored for longer time periods until it is finally consumend, these effects can be quite severe. Due to the actual logistical situation with comparably few cement plants, large delivery distances and partially less developed infrastructures, the latter scenario pictures the situation for the most cases in Africa quite well. In order to verify the relevance of the pre-hydation for practical application, a series of tests was conducted at the German Federal Institute for Materials Research and Testing (BAM). The influence of the cement storage on gresh and hardened concrete properties was investigated for different concrete and mortar types. The investigations show that the impact of the storage conditions is more pronounced for specialized concretes with high sophisticated optimized mixture compositions containing admixtures. Nevertheless, the effects also occur for ordinary concrete and should not be ignored. T2 - ACCTA - International conference on advances in cement and concrete technology in Africa 2013 CY - Johannesburg, South Africa DA - 28.01.2013 KW - Cement KW - Storage KW - Ambient conditions KW - Hydration KW - Pre-hydration KW - Atmospheric humidity PY - 2013 SN - 978-3-9815360-3-4 SP - 339 EP - 347 AN - OPUS4-27757 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -