TY - CONF A1 - Vasiliou, Eleni A1 - Schmidt, Wolfram A1 - Stefanidou, Maria A1 - Kühne, Hans-Carsten A1 - Rogge, Andreas ED - Amziane, Sofiane ED - Sonebi, Mohammed ED - Charlet, Karine T1 - Effectiveness of starch ethers as rheology modifying admixtures for cement based systems N2 - Polysaccharides are important rheology modifying admixtures in the building material sector. The use of starch is becoming increasingly important, due to many ecological and economic advantages. In the construction sector, starch ethers are being used as thickeners and as means to increase the yield stress. The starch ethers that are available on the market differ in their behaviour, which can vary greatly depending upon the binder system and mortar composition, e.g. solid volume content, binder type, additional admixtures. In view of the limited knowledge about the influence of molecular modifications associated with cement based systems, some fundamental rheological functional mechanisms were analysed in this study. The differently modified starch ethers used were derived from potatoes. They varied in their charges and degrees of hydroxypropylation. The setting and the flow behaviour of all examined variations of starch ethers were analysed in cement pastes. In order to illustrate the effects of the starch ethers that were used, the water-cement ratio (w/c) was held constant in all the mixtures [Schmidt 2012]. The results indicated significant differences in setting and flow behaviour. T2 - Second International RILEM Conference on Bio-based Building Materials CY - Clermont-Ferrand, France DA - 21.06.2017 KW - Rheology KW - Polysaccharides KW - Cement KW - Concrete KW - Starch KW - Polycarboxylate PY - 2017 SN - 978-2-35158-192-6 SP - 81 EP - 85 PB - RILEM S.A.R.L CY - Paris, France AN - OPUS4-43548 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Schmidt, Wolfram A1 - Tchetgnia Ngassam, Ines Leana ED - Schmidt, Wolfram ED - Tchetgnia Ngassam, Ines Leana T1 - Cement proficiency testing scheme 2016/2017 - Final report N2 - The cement proficiency testing (PT) scheme was set up by the German Metrology Institute (PTB) and the Federal Institute for Materials Research and Testing (BAM) in 2012. The PT scheme was a spin-off from a European Commission and African, Caribbean and Pacific-Group of States funded project entitled SPIN – Spearhead Network for Innovative, Clean and Safe Cement and Concrete Technologies (www.spin.bam.de). The SPIN project aimed at crosslinking experts in industry and policy making bodies, with the prospect of establishing a sustainable cement and concrete construction capacity in Africa. After a successful first pan-African proficiency testing scheme in 2012/2013, it was decided to establish the scheme permanently and independent of the SPIN project. The main focus of setting up a testing scheme was to enable all cement testing laboratories in Africa to evaluate their competence and efficiency in cement testing and further enhance their capacity to obtain better quality products according to their environment. The acronym developed for the PT scheme is PACE-PTS (Pan-African Cement Proficiency Testing Scheme). The framework for the PT scheme was set up jointly among the organisers and the first participants. The first PT scheme was initiated in Dar Es Salaam in 2012 followed by a final workshop in Berlin in 2013. The second PT scheme began in 2014. A final workshop was organised in Dar es Salaam in 2015. The third and current scheme was started in 2016 and the final workshop is held in Yaoundé. KW - PACE-PTS KW - Round Robin KW - Proficiency testing KW - Cement KW - Quality infrastructure PY - 2017 VL - 3 SP - 1 EP - 74 PB - BAM CY - Berlin AN - OPUS4-43546 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schmidt, Wolfram T1 - Potentials for sustainable cement and concrete technologies - Comparison between Africa and Europe N2 - Cement and concrete technologies in Africa provide vast potentials for sustainable future technologies as well as enormous challenges. The main focus of the symposium is to address existing challenges, possible solutions, and future potentials with all participants. This symposium also aims at offering a platform for networking with relevant players in science and industry. T2 - Cement and Concrete Related Issues for the African Market CY - Yaoundé, Cameroon DA - 02.11.2017 KW - Cement KW - Admixtures KW - Rheology KW - Sustainability KW - Environment PY - 2017 AN - OPUS4-43541 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schmidt, Wolfram A1 - Tchetgnia Ngassam, Ines Leana A1 - Breitschaft, Gerhard A1 - Virchow, Stephen T1 - Challenges of the growing African cement market – Environmental issues, regulative framework and quality infrastructure requirements N2 - The African cement, concrete and construction business are growing at rapid pace. The cement sales are expected to grow tremendously until 2050. The number of newly built cement plants increases dramatically and in addition more cements are being imported from outside the continent, e.g. from Turkey, Pakistan, Indonesia, and China, driven by overcapacities in the countries of origin. This causes a high number of potentials and challenges at the same time. New cement plants can operate directly at best technological state of the art and thus incorporate more sustainable technologies as well as produce new and more sustainable products such as cements blended with sustainable supplementary cementitious materials such as calcined clays, and industrial or agricultural by products. At the same time the new variety of binding agent as well as the international imports, which are driven by price considerations, make the cement market prone to quality scatter. This puts pressure on the quality control regulations and institutions to ensure safety of construction, healthy application, and environmental safety for the population. The paper presents possible solutions to build up the rapidly increasing African cement production more sustainably than in the rest of the world as well as the related challenges and obstacles that need to be overcome. Based on experiences with a series of pan-African cement testing laboratory proficiency schemes conclusions are made on technical, regulative and political level. T2 - 2nd International Congress on Materials & Structural Stability CY - Rabat, Morocco DA - 21.11.2017 KW - Quality infrastructure KW - Round Robin KW - Proficiency testing KW - Cement KW - Africa PY - 2017 AN - OPUS4-43543 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schmidt, Wolfram T1 - Bio-adhesives and bio-chemicals from bio-mass N2 - After a brief introduction into past and modern concrete, the relevance of sustainable concrete technologies is emphasised from a global perspective. In order to minimise the environmental impact of cement and concrete in the world, solutions for alternative binder materials as well as rheology and performance modifying additives are presented based on local bio-based resources. However, the perception of bio-based constituents is typically rather negative in construction materials and its application is often limited to low-end construction. In order to show that this is not inevitable, the lecture ends with a number of case studies for the use of bio-based materials for high performance concrete applications. T2 - Sustainable Adhesives from Bio-Mass (SAB) Symposium CY - Greensboro, North Carolina, USA DA - 26.01.2017 KW - Starch KW - Bio-based materials KW - Superplasticizer KW - Ash KW - Concrete KW - Cement PY - 2017 AN - OPUS4-43544 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schmidt, Wolfram T1 - Agricultureal Waste for High Performance Construction - Potentials for Innovation, Markets, and Sustainability N2 - The presentation provides an overview of potentials for high performance construction materials based on local agricultural waste materials in different regions in Africa. T2 - 5th German-African Infrastructure Forum 2017 CY - Düsseldorf, Germany DA - 08.11.2017 KW - Cement KW - Concrete KW - Bio-based materials KW - Sustainability KW - Africa PY - 2017 AN - OPUS4-43545 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schmidt, Wolfram T1 - Promising bio-based material solutions for more sustainable concrete N2 - Today, concrete engineers can vary consistencies between very stiff and self-compacting. At the same time engineers can opt for a vast variety of binders. The possibility to use optimised mineral binders and to tailor rheological properties of concrete eventually opened up the path to multiple new technologies, where design criteria are no longer limited to the Young’s modulus and the compressive strength, but often comprise additional added value. It can therefore be concluded that the capability to control the rheology and the interactions particles can be considered as the catalyst for concrete innovations such as polymer modified cementitious composites (PCC) self-compacting concrete (SCC), high-performance concrete (HPC), ultra-high performance concrete (UHPC) or strain hardening cement based composites (SHCC). In the same way rheology modifying additions, SCMs and admixtures will become key parameters in mastering the challenges of the next decades such as: - Additive manufacturing/3D-printing - Overcoming pumping height limitations - Casting at extreme temperatures - Tailored rheology at delivery In many regions in the Southern hemisphere the effective use of SCMs, additions and chemical admixtures for concrete could significantly contribute to solve problems induced by the challenging climatic conditions, but particularly in many countries with challenging climatic conditions, it is difficult to use them, due to lacking local supply and supply infrastructure, and often the awareness of the value of local mineral resources is missing. However, the long distance transportation of mineral resources and chemicals is not very environmentally friendly and the economic consequences are dramatic. However, bio-based constituents and chemicals have been used in construction for ages effectively. Due to the enormous relevance of binders, fillers and rheology modifying admixtures it is worthwhile to recollect that nature provides an enormous variety of products that can be used readily or with low processing. Today, the use of petrol based polycarboxylate ether superplasticizers has become quite common in concrete technology due to their versatility, but their uncomplicated and cost efficient availability is limited in many countries in the world. However, alternatives are available, which can be found locally. In addition many agricultural wastes today are dumped, although they could be converted to reactive ashes easily. Plant extracts have been used to modify the properties of concrete for long time. These plants are typically regionally abundantly available, cheap, and they are environmental friendly. They do not require special caring for seedlings, weeding or manuring to grow since they grow wildly. The talk will present an overview of various options for binders, fillers and rheology modifying admixtures, that can be found in nature, and that may become a real alternative, once their interaction within the complex cementitious system is well understood. T2 - Peak Forum on Sustainable Civil Engineering Materials CY - Shanghai, China DA - 18.05.2017 KW - Cement KW - Concrete KW - Sustainability KW - Bio-based materials KW - Polysaccharides KW - Supplementary cementitious materials PY - 2017 AN - OPUS4-41031 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schmidt, Wolfram T1 - Influence of nano scale effects on the macroscopic rheology N2 - Chemical admixtures like superplasticisers or stabilising agents are of ever increasing importance for modern concrete technology. They liberate the workability of concrete from its dependency on water content, and thus, open the gate towards innovative and future oriented concrete technologies. Meanwhile admixtures have become common practice in concrete technology, but the understanding of these highly complex polymers in the entire concrete system lags far behind their application. Due to its complex time-dependent, multi-phase and multi-scale behaviour, flowable concrete systems are highly complicated and cannot be described comprehensively by simple models. It is therefore extremely challenging to identify the relevant parameters that predominantly control flow phenomena on different size scales, since these may occur on any scale between the nano scale (e.g. superplasticizer adsorption) and macro scale (e.g. grading of the aggregates). The present study discusses fundamental mechanisms at the interface between particle or hydrate surfaces and the fluid phase at a very early stage of concrete formation, and links these effects to macroscopic flow phenomena. Based on the observations of the nano scale effects, it seems that higher sensitivity against variations in the constituents, the handling, or the boundary condition are the inevitable price for higher performances. However, eventually a very effective method is introduced that helps to maintain stable processes regardless of the root cause for performance changes based on an efficient in-situ process control scheme and superplasticizer and stabilising agents as counter actions. T2 - International Workshop on Nano-Engineered Meta-materials for Civil Infrastructures CY - Jinan, China DA - 20.5.2017 KW - Rheology KW - Meta materials KW - Nano engineering KW - Admixtures KW - Cement KW - Ettringite PY - 2017 AN - OPUS4-41032 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schmidt, Wolfram ED - Priebe, Nsesheye Susan T1 - Future civil engineering challenges - Skill requirements, new professional profiles and implementation N2 - Urbanisation, habitat, environment, infrastructure and sustainability are major global challenges of the 21st century. By planning, exploiting of resources, building, and maintaining, civil engineers and relevant adjacent disciplines have been carrying a large responsibility for the existing environmental problems. Civil engineers are responsible for 70% of all material uses in the world, and civil construction has been dominating the growth of the developing world for the next decades, with enormous impact on the global climate as well as the distribution of wealth and quality of living in the world. Today a variety of sustainable construction concepts have been developed and discussed. Recently a UNEP report was published, which provides a comprehensive overview of the challenges and potentials in the future from a scientific and industrial point of view. Sustainable solutions based on abundantly available resources (pozzolana and clay) or on renewable instead of limited industrial by-products (e.g. agricultural waste ashes) and new construction echnologies do exist. By applying, promoting and developing the implementation of the existing knowledge into real life constructions, civil engineers also hold the key for the mitigation of the global challenges. Using best practice sustainable construction solutions is particularly of highest importance in the developing world, since the implementation at an early stage creates the highest leverage for positive effects. T2 - 3rd Symposium on Knowledge Exchange for Young Scientists (KEYS) CY - Johannesburg, South Africa DA - 26.6.2017 KW - Civil Engineering KW - Cement KW - Concrete KW - Global engineering KW - Nano engineered materials KW - Sustainability PY - 2017 SN - 978-3-9818270-7-1 N1 - Geburtsname von Priebe, Nsesheye Susan: Msinjili, N. S. - Birth name of Priebe, Nsesheye Susan: Msinjili, N. S. VL - 3 SP - 9 EP - 14 PB - Bundesanstalt für Materialforschung und -prüfung (BAM) CY - Berlin AN - OPUS4-40975 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schmidt, Wolfram ED - Banjad Pecur, Ivana ED - Baricevic, Ana ED - Stirmer, Nina ED - Bjegovic, Dubravka T1 - Potentials for sustainable cement and concrete technologies - Comparison between Africa and Europe N2 - The fundamental knowledge about cement and concrete has made enormous progress over the last decades, and today it would be possible to find optimised sustainable concrete solutions tailored for every given boundary framework and raw material supply. However, this knowledge barely finds implementation into practice despite the urgent global need to minimise carbon emissions and energy consumption. A major reason is that most concrete developments were historically made in the northern hemisphere, where today over-regulations and stagnating market perspectives slow down innovation drive towards higher sustainability. In most African countries, however, sustainable building is simply an urgent real-life problem. The demand for building is enormous, Standard solutions are not an option, and the pool of innovative local raw materials and concrete concepts is enormous. The paper provides a comprehensive comparison between the boundary frameworks of Europe and Africa, and it is explained why local African solutions shall be given priority over imported solutions. Examples of local African concrete solutions are given, and ideas for a rapid implementation are developed. Most of the potentially useful materials such as agricultural ashes, natural and calcined pozzolans, polysaccharides, etc. have not yet been subject to intensive research to date. Therefore, it is not unlikely to assume that with an open mind for non-Standard solutions, combined with creativity and particularly knowledge and awareness, the next generation of innovative and sustainable concretes will be developed and applied on the African continent. Therefore, the conclusion is that particularly the African continent provides the best starting position to develop better and more sustainable concrete solutions than anywhere else in the world. Hence, Africa can become a global pioneer in green cement and concrete technology with impact to the entire world. N2 - Posljednih desetljeća načinjen je golem napredak u temeljnim znanjima o cementu i betonu. Danas bi bilo moguće naći rješenja za optimalni održivi beton primjeren svakom danom okviru i dobavi sirovina. Međutim, takvo znanje jedva da se primjenjuje u praksi unatoč hitnoj globalnoj potrebi smanjenja na najmanju mjeru emisija ugljika i potrošnje energije. Glavni je razlog što je većina razvoja u području betona tijekom povijesti načinjena u sjevernoj hemisferi gdje danas preregulacija i perspektiva stagnirajućeg tržišta usporavaju inovacije ka većoj održivosti. Međutim, u većini afričkih zemalja održiva gradnja jednostavno je hitni problem svakodnevice. Zahtjevi za gradnjom su golemi, obična rješenja nisu opcija, rezerve inovativnih lokalnih sirovina i mogućnosti primjene betona su golemi. U radu se daje sveobuhvatna usporedba graničnih okosnica Europe i Afrike, a objašnjeno je zašto se lokalnim afričkim rješenjima mora dati prioritet pred uvezenim rješenjima. Većina potencijalno korisnih materijala kao što su pepeli iz poljoprivrede, prirodni i kalcinirani pucolani, polisaharidi itd. do danas nisu bili predmetom intenzivnih istraživanja. Stoga nije nevjerojatno pretpostaviti da će se Nova generacija inovativnih i održivih betona razviti i primijeniti na afričkom kontinentu uz otvorenost prema nestandardnim rješenjima i u kombinaciji s kreativnošću i posebno znanjem i sviješću. Stoga je zaključeno da naročito afrički kontinent osigurava najbolju početnu poziciju za razvoj boljih i održivijih betona nego bilo gdje u svijetu. Prema tome Afrika može postati svjetski pionir u tehnologiji zelenoga cementa i betona s utjecajem na cijeli svijet. T2 - 1st International Conference on Construction Materials for a Sustainable Future CY - Zadar, Croatia DA - 19.4.2017 KW - Africa KW - Sustainability KW - Cement KW - Concrete KW - Admixtures KW - Carbon emissions PY - 2017 SN - 978-953-8168-04-8 SP - 829 EP - 835 CY - Zagreb, Croatia AN - OPUS4-40977 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -