Five samples were examined after hydration by scanning electron microscopy (SEM) and both before and after hydration by X-ray diffraction to establish microstructural and compositional data. The majority of the work was done on hydrated material. These samples consisted of three non-expansive cementitious and two expansive cementitious materials. The three non-expansive cementitious materials were an alite, a Type I portland cement, and a Type V portland cement. The two expansive cementitious materials were an ettringite-forming material and a Type K expansive cement.
Aside from water the materials which are used by mankind in highest quantities arecementitious materials and concrete. This book shows how the quality of the technical product depends on mineral phases and their reactions during the hydration and strengthening process. Additives and admixtures infl uence the course of hydration and the properties. Options of reducing the CO2-production in cementitious materials are presented and numerous examples of unhydrous and hydrous phases and their formation conditions are discussed. This editorial work consists of four parts including cement composition and hydration, Special cement and binder mineral phases, Cementitious and binder materials, and Measurement and properties. Every part contains different contributions and covers a broad range within the area. Contents Part I: Cement composition and hydration Diffraction and crystallography applied to anhydrous cements Diffraction and crystallography applied to hydrating cements Synthesis of highly reactive pure cement phases Thermodynamic modelling of cement hydration: Portland cements – blended cements – calcium sulfoaluminate cements Part II: Special cement and binder mineral phases Role of hydrotalcite-type layered double hydroxides in delayed pozzolanic reactions and their bearing on mortar dating Setting control of CAC by substituted acetic acids and crystal structures of their calcium salts Crystallography and crystal chemistry of AFm phases related to cement chemistry Part III: Cementitious and binder materials Chemistry, design and application of hybrid alkali activated binders Binding materials based on calcium sulphates Magnesia building material (Sorel cement) – from basics to application New CO2-reduced cementitious systems Composition and properties of ternary binders Part IV: Measurement and properties Characterization of microstructural properties of Portland cements by analytical scanning electron microscopy Correlating XRD data with technological properties No cement production without refractories
The characterization of the microstructure of a material should include two aspects: the identification of the microstructural elements in the material, and the quantitative characterization of these microstructural elements. In this research. the microstructure of hardened cement paste (hcp) was studied using BEI on polished surfaces coupled with image analysis. The microstructural elements evaluated included (a) pores detectable at the magnifications used, (b) CH crystals, (c) residual unhydrated cement particles, (d) hydrated phenograins, consisting of both hydration shells and fully hydrated cement grains, (e) combined phenograins, i.e. (c) and (d) combined as they occur in individual features, and (f) the C-S-H in the groundmass. The quantitative analyses assayed include both area fraction measurement and geometrical measurement of individual features. The latter provides information on size., shape, size distribution and mutual arrangement of the these individual features. Various hcps were investigated to quantitatively elucidate the effects of w:c ratio, age, and the incorporation of superplasticizer and silica fume on hcp microstructure. It was found that quantitative image analysis of hcp can yield interesting. and sometimes unexpected insights into the microstructure of hcp. The incorporation of superplasticizer and the incorporation of both superplasticizer and silica fume showed very strong effects on the hcp microstructure. On the other hand silica fume alone did not show strong effects. In another portion of this research, the fractal dimension characteristic of the pore system of hcp was investigated using an image analysis technique. It was found that the detectable pore system in cement pastes shows two fractal regimes: a structural fractal dimension exhibited at low resolution (Ds = 1.08 ~ 1.15) and a textural fractal dimension exhibited at higher resolution (Dt = 1.22 ~ 1.49). Finally, using a stereoscopic SEM method, it was found that the fracture surface of cement pastes shows two distinct fractal regimes: a structural fractal regime at low magnifications descriptive of the gross structural irregularities, and a textural fractal at high magnifications descriptive of the textural details of the fracture surface. The structural fractal and the textural fractal seem to have universal values of 2.02 and 2.12 respectively.
- Concrete - Deterioration of concrete - In situ investigation of concrete deterioration - Laboratory testing - X-ray diffraction analysis - Scanning electron microscopy and micro-analysis - Physiochemical examination of concrete - Case studies - Appendix 1 Data interpretation - Appendix 2 Interaction between radiation and a solid - Appendix 3 Structure and description of crystals - Appendix 4 Mineralogical data - Index
This classic reference has established the value of petrography as a powerful method for the investigation of concrete as a material. It provides an authoritative and well-illustrated review of concrete composition and textures, including the causes of defects, deterioration, and failure that can be identified using a petrological microscope. This new edition is entirely revised and updated and also greatly extended to take account of new scientific developments and significant improvements in instrumentation and to reflect current laboratory working practices, as well as to reflect new understanding of the performance of concrete and related materials. Now in full color throughout, Concrete Petrography, Second Edition provides case study examples, with appropriate explanatory discussions and practical advice on selecting, handling and preparing specimens. It assists and guides the engineer, the trainee and the experienced petrographer in understanding the scientific evidence that is basic to petrographic analysis and so will lead to more accurate and timely diagnosis and treatment of problems in structural concrete. This book includes: Contributions in specialist areas by internationally recognized experts Explanation of computer techniques as an aid to petrography Full coverage of inspection, sampling, and specimen preparation New sections covering recent technological development of equipment Guidance on observation of cement and concrete mineralogy and microfabrics Discussion and illustrative examples of deterioration and failure mechanisms New work and guidance on the determination of water/cement ratio New color illustrations and micrographs throughout Thorough updating of standards, other authoritative publications, and references A fully revised, extended, and updated glossary of optical and other properties
This book highlights the latest advances, innovations, and applications in cement-based materials (CBM) and concrete structures, as presented by leading international researchers and engineers at the International RILEM Conference on synergizing expertise toward sustainability and robustness of CBM and concrete structures (SynerCrete), held in Milos Island, Greece, on June 14-16, 2023. The aim of the conference was to discuss and arouse progress in research, development, and application of CBM and structural concrete through combination of expertise from distinct fields of knowledge, such as performance-based design, 3D modeling for analysis/design, building information modeling, and even robotics, while keeping focus on multiscale approaches at time and spatial levels. It covers a diverse range of topics concerning alternative concrete formulations for adaptation to climate change, performance-based and multiphysics/multiscale design and innovative testing, structural health monitoring and maintenance management, integral BIM-based planning, and resource-responsible building. The contributions, which were selected by means of a rigorous international peer-review process, present a wealth of exciting ideas that will open novel research directions and foster new multidisciplinary collaborations. The two volumes encompass more than 200 original contributions in the field.
A revised and updated text on cement chemistry. This edition forms a comprehensive and in-depth reference work that explains in detail all aspects of cement chemistry.
