FG Baustoffe und Bauchemie

19 Items

Recent Submissions
Interaction of Different Charged Polymers with Potassium Ions and Their Effect on the Yield Stress of Highly Concentrated Glass Bead Suspensions

Lu, Zichen ; Becker, Simon ; Leinitz, Sarah ; Schmidt, Wolfram ; von Klitzing, Regine ; Stephan, Dietmar (2020-03-25)

The interaction of different charged polymers, namely anionic polycarboxylate superplasticizer (PCE) and neutral polyethylene glycol (PEG) with potassium ions, and their effect on the yield stress of highly concentrated glass bead suspension (GBS), were studied under different concentrations of potassium ions ([K+]). It was found that, compared to the neutral PEG, the negatively charged PCE can...

An Investigation of the Mechanical and Physical Characteristics of Cement Paste Incorporating Different Air Entraining Agents using X-ray Micro-Computed Tomography

Abd Elrahman, Mohamed ; El Madawy, Mohamed E. ; Chung, Sang-Yeop ; Majer, Stanisław ; Youssf, Osama ; Sikora, Pawel (2020-01-06)

Improving the thermal insulation properties of cement-based materials is the key to reducing energy loss and consumption in buildings. Lightweight cement-based composites can be used efficiently for this purpose, as a structural material with load bearing ability or as a non-structural one for thermal insulation. In this research, lightweight cement pastes containing fly ash and cement were pre...

Investigation of the Incompatibilities of Cement and Superplasticizers and Their Influence on the Rheological Behavior

Pott, Ursula ; Jakob, Cordula ; Jansen, Daniel ; Neubauer, Jürgen ; Stephan, Dietmar (2020-02-21)

The rheological behavior of cement paste and the improvement of its flowability takes center stage in many research projects. An improved flowability can be achieved by the addition of superplasticizers (SP), such as polycarboxylate ethers (PCE). In order to be able to use these PCEs effectively and in a variety of ways and to make them resistant to changes in the environment, it is crucial to ...

Enchytraeus crypticus Avoid Soil Spiked with Microplastic

Pflugmacher, Stephan ; Huttunen, Johanna H. ; Wolff, Marya-Anne von ; Penttinen, Olli-Pekka ; Kim, Yong Jun ; Kim, Sanghun ; Mitrovic, Simon M. ; Esterhuizen-Londt, Maranda (2020-02-10)

Microplastics (MPs) of varying sizes are widespread pollutants in our environment. The general opinion is that the smaller the size, the more dangerous the MPs are due to enhanced uptake possibilities. It would be of considerably ecological significance to understand the response of biota to microplastic contamination both physically and physiologically. Here, we report on an area choice experi...

Study on the production of core-shell structured lightweight aggregate by cold-bonding agglomeration process and its utilization in concrete

Tajra, Feras (2020)

Lightweight aggregate concrete has been widely used in different construction applications due to its advantageous characteristics such as low density, low thermal conductivity and good durability properties. Compared to conventional concrete, lightweight aggregate concrete is made by replacing normal weight aggregate with lightweight aggregate, which is taken from natural resources or produced...

Photocatalytic Activity and Mechanical Properties of Cements Modified with TiO2/N

Janus, Magdalena ; Mądraszewski, Szymon ; Zając, Kamila ; Kusiak-Nejman, Ewelina ; Morawski, Antoni W. ; Stephan, Dietmar (2019-11-14)

In this paper, studies of the mechanical properties and photocatalytic activity of new photoactive cement mortars are presented. The new building materials were obtained by the addition of 1, 3, and 5 wt % (based on the cement content) of nitrogen-modified titanium dioxide (TiO2/N) to the cement matrix. Photocatalytic active cement mortars were characterized by measuring the flexural and the co...

Accident Rate as a Measure of Safety Assessment in Polish Civil Engineering

Cieslewicz, Wieslawa ; Araszkiewicz, Krystyna ; Sikora, Pawel (2019-10-30)

Civil engineering is characterised by high volatility with respect to working conditions, which are the source of many threats to worker life and health and contribute to high accident rates. The purpose of this paper is to analyse and evaluate the phenomenon of accidents in Polish civil engineering and define the direction of changes that should occur in the safety area. The studies included i...

Relating Ettringite formation and rheological changes during the Initial cement hydration

Jakob, Cordula ; Jansen, Daniel ; Ukrainczyk, Neven ; Koenders, Eddie ; Pott, Ursula ; Stephan, Dietmar ; Neubauer, Jürgen (2019-09-12)

In order to gain a deeper understanding of the rheological development of hydrating ordinary Portland cement (OPC) pastes at initial state, and to better understand their underlying processes, quantitative X-ray diffraction (XRD) analysis and rheological measurements were conducted and their results combined. The time-dependent relation between phase development and flow behavior of cement past...

Influence of Nanosilica on Mechanical Properties, Sorptivity, and Microstructure of Lightweight Concrete

Abd Elrahman, Mohamed ; Chung, Sang-Yeop ; Sikora, Pawel ; Rucinska, Teresa ; Stephan, Dietmar (2019-09-21)

This study presents the results of an experimental investigation of the effects of nanosilica (NS) on the strength development, transport properties, thermal conductivity, air-void, and pore characteristics of lightweight aggregate concrete (LWAC), with an oven-dry density <1000 kg/m3. Four types of concrete mixtures, containing 0 wt.%, 1 wt.%, 2 wt.%, and 4 wt.% of NS were prepared. The develo...

Characterization data of reference cement CEM I 42.5 R used for priority program DFG SPP 2005 “Opus Fluidum Futurum – Rheology of reactive, multiscale, multiphase construction materials”

Lu, Zichen ; Haist, Michael ; Ivanov, Dimitri ; Jakob, Cordula ; Jansen, Daniel ; Leinitz, Sarah ; Link, Julian ; Mechtcherine, Viktor ; Neubauer, Jürgen ; Plank, Johann ; Schmidt, Wolfram ; Schilde, Carsten ; Schröfl, Christof ; Sowoidnich, Thomas ; Stephan, Dietmar (2019-10-22)

A thorough characterization of starting materials is the precondition for further research, especially for cement, which contains various phases and presents quite a complex material for fundamental scientific investigation. In the paper at hand, the characterization data of the reference cement CEM I 42.5 R used within the priority program 2005 of the German Research Foundation (DFG SPP 2005) ...

Preparation and Characterization of Ultra-Lightweight Foamed Concrete Incorporating Lightweight Aggregates

Abd Elrahman, Mohamed ; El Madawy, Mohamed E. ; Chung, Sang-Yeop ; Sikora, Pawel ; Stephan, Dietmar (2019-04-06)

Increasing interest is nowadays being paid to improving the thermal insulation of buildings in order to save energy and reduce ecological problems. Foamed concrete has unique characteristics and considerable potential as a promising material in construction applications. It is produced with a wide range of dry densities, between 600 and 1600 kg/m3. However, at a low density below 500 kg/m3, it ...

Pore Characteristics and Their Effects on the Material Properties of Foamed Concrete Evaluated Using Micro-CT Images and Numerical Approaches

Chung, Sang-Yeop ; Lehmann, Christian ; Abd Elrahman, Mohamed ; Stephan, Dietmar (2017-05-26)

Foamed concrete contains numerous pores inside the material, and these pores are a significant factor determining the material characteristics. In particular, the pore distribution characteristics of foamed concrete significantly affect its thermal and mechanical properties. Therefore, an appropriate investigation is necessary for a more detailed understanding of foamed concrete. Here, a set of...

Effect of Different Gradings of Lightweight Aggregates on the Properties of Concrete

Chung, Sang-Yeop ; Abd Elrahman, Mohamed ; Stephan, Dietmar (2017-06-07)

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Bitumen und Chemometrie

Weigel, Sandra (2018)

Im Rahmen dieser Arbeit konnte gezeigt werden, dass mithilfe der Fourier-Transformations-Infrarotspektroskopie und der Anwendung multivariater Analysemethoden eine umfassende Charakterisierung von Bitumenproben möglich ist. Als Grundlage dienten 90 Straßenbaubitumen unterschiedlicher Herkunft, Alterungsstufe und Sorte, die mithilfe verschiedener chemischer und physikalischer Verfahren untersuch...

The influence of nanomaterials on the thermal resistance of cement-based composites – a review

Pawel, Sikora ; Abd Elrahman, Mohamed ; Stephan, Dietmar (2018-06-26)

Exposure to elevated temperatures has detrimental effects on the properties of cementitious composites, leading to irreversible changes, up to total failure. Various methods have been used to suppress the deterioration of concrete under elevated temperature conditions. Recently, nanomaterials have been introduced as admixtures, which decrease the thermal degradation of cement-based composites a...

Evaluation of the effects of crushed and expanded waste glass aggregates on the material properties of lightweight concrete using image-based approaches

Chung, Sang-Yeop ; Abd Elrahman, Mohamed ; Sikora, Pawel ; Rucinska, Teresa ; Horszczaruk, Elzbieta ; Stephan, Dietmar (2017-11-25)

Recently, the recycling of waste glass has become a worldwide issue in the reduction of waste and energy consumption. Waste glass can be utilized in construction materials, and understanding its effects on material properties is crucial in developing advanced materials. In this study, recycled crushed and expanded glasses are used as lightweight aggregates for concrete, and their relation to th...

Leaching of inorganic and organic substances from construction materials and their ecotoxicological impact

Märkl, Veronika (2018)

In the last few years a growing environmental awareness in the field of construction materials can be observed. This has been, and continues to be, exacerbated since the Construction Products Regulations entered into force in 2013. In general construction products are in direct contact with the surrounding environment such as groundwater and soil. Especially grouting materials that often contai...

Alkalisch aktivierte Systeme auf Basis von Hüttensandmehlen

Tänzer, Ricarda (2018)

Alternative Bindemittel besitzen ökonomische und ökologische Vorteile sowie eine Vielzahl an positiven Eigenschaften (hoher Widerstand gegen aggressive Medien, hohe Druckfestigkeit, hoher Frostwiderstand, geringe beziehungsweise schnelle Abgabe von Reaktionswärme, geringe Porosität oder hohe Temperaturbeständigkeit). Die Eigenschaften hängen aber maßgeblich von der Art des Bindemitteltyps ab. F...

The 2015 Annual Meeting of SETAC German Language Branch in Zurich (7-10 September, 2015): ecotoxicology and environmental chemistry-from research to application

Werner, Inge ; Aldrich, Annette ; Becker, Benjamin ; Becker, Dennis ; Brinkmann, Markus ; Burkhardt, Michael ; Caspers, Norbert ; Campiche, Sophie ; Chèvre, Nathalie ; Düring, Rolf-Alexander ; Escher, Beate I. ; Fischer, Fabian ; Giebner, Sabrina ; Heye, Katharina ; Hollert, Henner ; Junghans, Marion ; Kienle, Cornelia ; Knauer, Katja ; Korkaric, Music ; Märkl, Veronika ; Muncke, Jane ; Oehlmann, Jörg ; Reifferscheid, Georg ; Rensch, Daniel ; Schäffer, Andreas ; Schiwy, Sabrina ; Schwarz, Simon ; Triebskorn, Rita ; Vermissen, Etiënne L. M. ; Wintgens, Thomas ; Zennegg, Markus (2016)

This report provides a brief review of the 20th annual meeting of the German Language Branch of the Society of Environmental Toxicology and Chemistry (SETAC GLB) held from September 7th to 10th 2015 at ETH (Swiss Technical University) in Zurich, Switzerland. The event was chaired by Inge Werner, Director of the Swiss Centre for Applied Ecotoxicology (Ecotox Centre) Eawag-EPFL, and organized by ...