Performance Of Cement Based Materials In Aggressive Aqueous Environments

Concrete and cement-based materials must operate in increasingly aggressive aqueous environments, which may be either natural or industrial. These materials may suffer degradation in which ion addition and/or ion exchange reactions occur, leading to a breakdown of the matrix microstructure and consequent weakening. Sometimes this degradation can be extremely rapid and serious such as in acidic environments, while in other cases degradation occurs over long periods. Consequences of material failure are usually severe – adversely affecting the health and well-being of human communities and disturbing ecological balances. There are also large direct costs of maintaining and replacing deteriorated infrastructure and indirect costs from loss of production during maintenance work, which place a great burden on society. The focus of this book is on addressing issues concerning performance of cement-based materials in aggressive aqueous environments , by way of this State-of-the-Art Report. The book represents the work of many well-known and respected authors who contributed chapters or parts of chapters. Four main themes were addressed: I. Nature and kinetics of degradation and deterioration mechanisms of cement-based materials in aggressive aqueous environments, II. Modelling of deterioration in such environments, III. Test methods to assess performance of cement-based materials in such environments, and which can be used to characterise and rate relative performance and inform long term predictions, IV. Engineering implications and consequences of deterioration in aggressive aqueous environments, and engineering approaches to the problem.

Self-healing materials are man-made materials which have the built-in capability to repair damage. Failure in materials is often caused by the occurrence of small microcracks throughout the material. In self-healing materials phenomena are triggered to counteract these microcracks. These processes are ideally triggered by the occurrence of damage itself. Thus far, the self-healing capacity of cement-based materials has been considered as something "extra". This could be called passive self-healing, since it was not a designed feature of the material, but an inherent property of it. Centuries-old buildings have been said to have survived these centuries because of the inherent self-healing capacity of the binders used for cementing building blocks together. In this State-of-the-Art Report a closer look is taken at self-healing phenomena in cement-based materials. It is shown what options are available to design for this effect rather than have it occur as a "coincidental extra".

This book presents the work of the RILEM Technical Committee 276-DFC: Digital fabrication with cement-based materials. The most important outcomes of the technical committee are presented. First, a unified process classification for digital fabrication with concrete is proposed, discussed and illustrated. Then, a state of the art of the testing methods (both at a material and structural level and in the fresh and hardened state) is provided. The gathered knowledge is expected to form the foundation of some quality control procedures for fresh properties along with hardened properties and service life performance. The book will benefit academics, practitioners, industry and standardization committees interested in digital fabrication with cement-based materials.

This book presents the work of the RILEM TC 266-MRP, whose purpose was to enhance the reliability of rheological measurements performed on cement-based materials. It makes users more aware of potential sources of errors in the measurements, and provide guidelines on how to observe, counteract or eliminate the errors. Improving the reliability of rheological measurements will further enhance the use of rheology to investigate different aspects of the fresh properties of cement-based materials. After an introduction into mix design and applications, the book delivers a comprehensive overview of rheology definitions, behavior, and parameters; rheometers; measuring and analysis procedures; difficulties and challenges during measurements; relationships with specific empirical tests; and the behavior of concrete near a surface. This report on the measurement of rheological properties of complex materials such as concrete enables readers to understand the applicable concepts of rheology, and address the challenges on the measuring procedures, the rheological models and some errors and limitations of rheometers used.

This work gives an overview of significant research from recent years concerning performance-based design and quality control for concrete durability and its implementation. In engineering practice, performance approaches are often still used in combination with prescriptive requirements. This is largely because, for most durability test methods, sufficient practical experience still has to be gained before engineers and owners are prepared to fully rely on them. This book, compiled by RILEM TC 230-PSC, is intended to assist efforts to successfully build the foundation for the full implementation of performance-based approaches through the exchange of relevant knowledge and experience between researchers and practitioners worldwide.

Among different approaches that can be considered for concrete rehabilitation, bonded overlays are often the most economical alternative. The primary purpose of overlays is to extend the life of the candidate structures, either by restoring the quality and integrity of the surface and/or the re-establishing or improving the load-carrying capacity. Nevertheless, the durability of bonded overlay systems still draws concerns in the technical community because of bond sustainability problems encountered in a number of cases. At this time, there is still no accepted design approach or methodology that can warrant the practitioner a successful outcome of the repair. This State-of-Art report summarizes the findings with respect to all aspects involved in the overlaying process.

This book captures the state of the art of the durability of fibre-reinforced strain-hardening cement-based composites (SHCC) and the durability of structures or structural elements manufactured in full or in part with this class of modern construction materials. Highlights include: - Reflection on durability performance of existing applications in patch repair, a water reservoir and highway bridges. - Guidelines for tensile testing towards durability assessment of cracked SHCC. - New crack pattern related ingress rate indices for water and chloride into cracked SHCC. - The influence of low and high temperatures on SHCC durability performance. - The mechanism of crack control reducing ASR and corrosion rate, and results on chloride-induced corrosion of embedded steel reinforcement. - Self-healing of cracks in SHCC. - A conceptual durability design framework for SHCC and R/SHCC structures and members.

This new volume presents various research studies that focus on the development of advanced nanomaterials and their composites and blends for different applications in sensing, electrical, biomedical, coating, industrial applications, etc. This book includes detailed discussions on the synthesis, properties, processing, and potential applications of nanomaterials and their blends and composites. Some chapters also explain the basic theoretical aspects of these nanostructured materials and systems, which help readers to develop a better understanding various application areas, including construction. Nanostructured Smart Materials: Synthesis, Characterization and Potential Applications responds to the need for advanced polymeric materials and nanostructured materials with ultimate performance and enhanced qualities and properties for varied applications. The chapters highlight information and research that will be valuable for development of new smart materials. This book will be a useful reference source for universities, colleges, researchers from R&D groups, scientists, postdoctoral fellows, industrialists, graduate and postgraduate students, and faculty.