State-of-the-Art Evaluation of Repository Sealing Materials and Techniques.

1987 ◽  
Vol 112 ◽  
Author(s):  
Paul Gnirk
Keyword(s):  
State Of The Art ◽  
Indirect Evidence ◽  
Crystalline Rock ◽  
Cementitious Materials ◽  
Natural Clay ◽  
Fracture Sealing ◽  
Sealing Materials ◽  
Clay Materials ◽  
Repository Sealing ◽  
Art Evaluation

AbstractUnder the auspices of the OECD/NEA Stripa Project, a state-of-the-art evaluation of repository sealing materials and techniques has been undertaken with particular application to crystalline rock. The objectives of the evaluation were (1) to review progress to date in the development of repository sealing materials and emplacement techniques; (2) to identify priority materials for sealing narrow aperture fractures in crystalline rock, including issues of technical concern to the long-term effectiveness of such materials; and (3) to provide a framework for advancing an in situ fracture-sealing test program that can be designed and implemented at the Stripa Mine.The classes of sealing materials that were considered included cementitious materials, natural clay materials, chemical grouts, fracture-filling synthetic minerals, ceramics, and metals. Of these, cementitious materials and natural clay materials were recommended as high-priority materials for further study because they can be designed to meet desired repository performance characteristics, there is considerable history of successful use in similar engineering applications, and there is indirect evidence that they will continue to perform as expected for long periods of time. Techniques for the emplacement of these sealing materials in rock fractures include pressure injection, dynamic (or vibratory) injection, and electrophoresis.

State of the art on geopolymer concrete

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Zoi G. Ralli ◽  
Stavroula J. Pantazopoulou
Keyword(s):  
Mechanical Performance ◽  
State Of The Art ◽  
Construction Materials ◽  
Cementitious Materials ◽  
Sustainable Construction ◽  
Geopolymer Concrete ◽  
Critical Material ◽  
Content Type ◽  
Critical Requirement

PurposeImportant differentiating attributes in the procedures used, the characteristic mineral composition of the binders, and the implications these have on the final long term stability and physico-mechanical performance of the concretes produced are identified and discussed, with the intent to improve transparency and clarity in the field of geopolymer concrete technologies.Design/methodology/approachThis state-of-the-art review covers the area of geopolymer concrete, a class of sustainable construction materials that use a variety of alternative powders in lieu of cement for composing concrete, most being a combination of industrial by-products and natural resources rich in specific required minerals. It explores extensively the available essential materials for geopolymer concrete and provides a deeper understanding of its underlying chemical mechanisms.FindingsThis is a state-of-the-art review introducing the essential characteristics of alternative powders used in geopolymer binders and the effectiveness these have on material performance.Practical implicationsWith the increase of need for alternative cementitious materials, identifying and understanding the critical material components and the effect they may have on the performance of the resulting mixes in fresh as well as hardened state become a critical requirement to for short- and long-term quality control (e.g. flash setting, efflorescence, etc.).Originality/valueThe topic explored is significant in the field of sustainable concrete technologies where there are several parallel but distinct material technologies being developed, such as geopolymer concrete and alkali-activated concrete. Behavioral aspects and results are not directly transferable between the two fields of cementitious materials development, and these differences are explored and detailed in the present study.

Preparation of Organovermiculite for Adsorption of Organic Compounds

2012 ◽  
Vol 727-728 ◽  
pp. 1451-1456
Author(s):  
Andréa Lopes Silva ◽  
Francisco Kegenaldo Alves de Souza ◽  
Gelmires Araújo Neves ◽  
Romualdo Rodrigues Menezes ◽  
Hélio Lucena Lira ◽  
...  
Keyword(s):  
Organic Compounds ◽  
Organic Pollutants ◽  
Organic Contaminants ◽  
Exchange Capacity ◽  
Natural Clay ◽  
Modified Clay ◽  
Organically Modified ◽  
Dimethyl Ammonium ◽  
Cationic Exchange ◽  
Clay Materials

Organically modified clay minerals are widely used as sorbents for hydrophobic organic compounds e.g., organic pollutants treatment from water solutions. Natural clay materials are hydrophilic and therefore they are not efficient sorbents for organic compounds. Intercalations of natural clay materials, with organic cations, with quaternary ammonium groups may become these clays hydrophobic. Vermiculite is the mineralogical name given to hydrated laminar magnesium-aluminum-iron silicate; this natural clay was modified and used for the production of organically modified clay (organovermiculite), with the purpose of its use in removing organic contaminants. The organovermiculite was prepared using different concentrations of distearyl dimethyl ammonium chloride (praepagen) based on cationic exchange capacity of the clay. It was evident from the X-ray diffraction that the salt was incorporated to the clay structure confirming its organophilization and through the Foster swelling test it was observed the affinity between the organic pollutants and the organovermiculite.

scholarly journals A robust and parsimonious model for caesium sorption on clay minerals and natural clay materials

2017 ◽  
Vol 87 ◽  
pp. 22-37 ◽  
Author(s):  
Mohamed A. Cherif ◽  
Arnaud Martin-Garin ◽  
Frédéric Gérard ◽  
Olivier Bildstein
Keyword(s):  
Clay Minerals ◽  
Natural Clay ◽  
Parsimonious Model ◽  
Clay Materials

scholarly journals The Use of SEM and Other Complimentary Techniques for the Determination of Properties of Cementitious Materials

1992 ◽  
Vol 00 (8) ◽  
pp. 4-4 ◽  
Author(s):  
Eric A. Draper ◽  
Jan Skalny
Keyword(s):  
Building Materials ◽  
State Of The Art ◽  
Raw Materials ◽  
Cementitious Materials ◽  
Modern State ◽  
Microscopic Evaluation ◽  
The World ◽  
Cost Effect

The need for continued rehabilitation of our concrete infrastructure has lead to the adaptation of modern “state-of-the-art” analytical methods for the characterization of concrete and other cementitious materials. Some of these techniques have not, until relatively recently, been commonly associated with the evaluation of concrete but are very useful both as tools for quality assurance and in the determination of the extent of existing damage. The technique of interest here is the coordinated electron-optical microscopic evaluation of concrete.Concrete is the most widely used building material in the world. Contrary to popular belief, concrete is not inert but chemically very complex and dynamic. While it is true that, pound for pound, concrete and its raw materials (cement, aggregate and water} are the most inexpensive building materials available for construction, it is also true that it responds to its environment in numerous and sometimes very subtle ways. These responses may sometimes result in a loss of durability and tremendous amounts of time and money being expended while searching for the cause(s) of the problem and providing a cost-effect solution A quick survey of any large metropolitan area and the on-going construction repairs to highways and bridge decks there will quickly confirm this.

scholarly journals Clay calcination technology: state-of-the-art review by the RILEM TC 282-CCL

2021 ◽  
Vol 55 (1) ◽  
Author(s):  
Theodore Hanein ◽  
Karl-Christian Thienel ◽  
Franco Zunino ◽  
Alastair T. M. Marsh ◽  
Matthias Maier ◽  
...  
Keyword(s):  
State Of The Art ◽  
Deep Understanding ◽  
Cementitious Materials ◽  
Global Scale ◽  
Supplementary Cementitious Materials ◽  
Infrastructure Development ◽  
Sustainable Infrastructure ◽  
Calcination Process ◽  
Current State ◽  
Group 2

AbstractThe use of calcined clays as supplementary cementitious materials provides the opportunity to significantly reduce the cement industry’s carbon burden; however, use at a global scale requires a deep understanding of the extraction and processing of the clays to be used, which will uncover routes to optimise their reactivity. This will enable increased usage of calcined clays as cement replacements, further improving the sustainability of concretes produced with them. Existing technologies can be adopted to produce calcined clays at an industrial scale in many regions around the world. This paper, produced by RILEM TC 282-CCL on calcined clays as supplementary cementitious materials (working group 2), focuses on the production of calcined clays, presents an overview of clay mining, and assesses the current state of the art in clay calcination technology, covering the most relevant aspects from the clay deposit to the factory gate. The energetics and associated carbon footprint of the calcination process are also discussed, and an outlook on clay calcination is presented, discussing the technological advancements required to fulfil future global demand for this material in sustainable infrastructure development.

Sign in / Sign up

Export Citation Format

Share Document