Download or read book Performance of Concrete with Blended Binders in Sulfuric Acid and Ammonium Sulphate Solutions written by Mahmud Amin and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Acid attacks on concrete impart unique set of damage mechanisms and manifestations compared to other durability issues of concrete. Up to date, there are still research gaps and conflicting data regarding the effects of supplementary cementitious materials (SCMs) at improving the resistance of concrete to acidic exposures. Hence, this thesis aims at understanding the role of SCMs in the performance of concrete under two different acidic environments (sulfuric acid and ammonium sulfate solutions) that produce similar reaction products while their damage mechanisms and manifestations are completely different. Concrete has long been the most popular choice for constructing key infrastructural elements such as sewer pipes, water treatment facilities, industrial floors and foundations, which can be chemically vulnerable to damage by sulfuric acid attack. Since high alkalinity is required for the stability of the cementitious matrix, concrete is susceptible to attack by acidic media, which may disintegrate the hydrated cement paste to various levels based on the prevailing exposure conditions and key mixture design parameters of concrete. The aim of this part of research was to investigate the response, in terms of phyico-mechanical and microstructural features, of concrete comprising different types of cement (general use or portland limestone cement [PLC]) with various combinations of SCMs (fly ash, silica fume and nano-silica) to a severe sulfuric acid exposure. The project comprised 13 weeks (90 days) of immersing test specimens in 5% sulfuric acid solutions with a maximum pH threshold of 2.0. The results revealed that the surface degradation (mass loss) of concrete under severe sulfuric acid attack was independent of its penetrability (physical resistance), since very dense cementitious matrices (low penetrability) suffered from severe deterioration. Portland limestone cement [PLC] may slightly improve the resistance of concrete to sulfuric acid attack, whereas among the blended binders tested, binary binders comprising 30% fly ash showed increased resistance of concrete to sulfuric acid attack due to an inert filler effect at the exposed surface. On the other hand, concrete elements in agricultural, wastewater treatment, mining and industrial applications can be vulnerable to chemical attack by ammonium-based solutions. In particular, ammonium sulfate (commonly used as a fertilizer) is extremely deleterious to concrete due to its dual acid-sulfate action, which may disintegrate the hydrated cement paste to various levels based on the prevailing exposure conditions and key mixture design parameters of concrete. The aim of the second part of research was to investigate the response, in terms of physico-mechanical and microstructural features, of concrete comprising different types of cement (general use or PLC) with various combinations of SCMs (fly ash, silica fume and nano-silica) to a severe ammonium sulfate exposure. This part comprised 12 months of immersing test specimens in 5% ammonium sulfate solutions with a pH level of 6.0-8.0. The results revealed that the type of binder along with the dosage and nature of SCMs dictated different modes and levels of deterioration, and in turn physico-mechanical trends of concrete characterised by softening with (single binders) or without (blended binders) significant expansion. PLC may slightly improve the resistance of concrete to ammonium attack, whereas among the blended binders tested, binary binders comprising 5% silica fume, 5% nano-silica, or 30% fly ash particularly improved the resistance of concrete to this type of chemical attack.
Download or read book Durability of Concrete Incorporating Blended Binders and Alkali activated Materials to Sulfuric Acid Environments written by Mohamed Hussien Mahmoud and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Acidic attack on concrete imparts unique set of damage mechanisms and manifestations compared to other durability issues of concrete. Sulfuric acid attack limits the service life of concrete elements and, thus, results in increased expenditures for the repair or in some cases replacement of the whole structure. To date, there is lack of standardized tests for specifically evaluating the resistance of concrete to sulfuric acid attack, which has caused great variability, for example in terms of solution concentration, pH level/control, etc., among previous studies in this area. Accordingly, there are conflicting data about the role of key constituents of concrete (e.g. supplementary cementitious materials [SCMs]), and uncertainty about building codes' stipulations for concrete exposed to sulfuric acid. Hence, the first objective of this thesis was to assess the behaviour of the same concretes, prepared with single and blended binders, to incremental levels (mild, severe and very severe) of sulfuric acid solutions over 36 weeks. The test variables included the type of cement (general use [GU] or portland limestone cement [PLC]) and SCMs (fly ash, silica fume and nano-silica). The severe (1%, pH of 1) and very severe aggression (2.5%, pH of 0.5) phases caused mass loss of all specimens, with the latter phase providing clear distinction among the performance of concrete mixtures. The results showed that the penetrability of concrete was not a controlling factor, under severe and very severe damage by sulfuric acid attack, whereas the chemical vulnerability of the binder was the dominant factor. Mixtures prepared from PLC performed better than that of counterparts made from GU. While the quaternary mixtures comprising GU or PLC, fly ash, silica fume and nanosilica showed the highest mass losses after 36 weeks, binary mixtures incorporating GU or PLC with fly ash had the lowest mass losses. Several studies reported that the improved chemical resistance of alkali-activated materials (AAMs) over concrete based on portland cements. However, AAMs have technical limitations, which might deter its widespread use in cast-in place applications. These limitations include need for heat curing, slow setting, and slow strength development, which might be mitigated by further improving the reactivity of AAMs during early-age with nanoparticles; however, this area remains largely unexplored. Hence, the second objective of this thesis was to develop innovative types of AAMs-based concrete [alkali activated fly ash (AAFA), alkali activated slag (AAS) and their blends incorporating nanosilica] and evaluate their resistance to two different sulfuric acid exposures over 18 weeks for potential use in repair of concrete elements vulnerable to acidic attack. While AAFA specimens, produced without heat curing, experienced rapid ingress of the acidic solution and a significant reduction in the bond strength with substrate concrete, fly ash based AAMs comprising slag and or nanosilica (AAFA-S and AAFA-S-NS) had improved performance due to discounting the ingress of acidic solution and continued geopolymerization reactivity. Comparatively, specimens from the slag group exhibited high levels of swelling, internal cracking and mass loss due to chemical deterioration. The overall results suggest that AAFA-S and AAFA-S-NS mixture, without heat curing, may be a viable option for repair applications of concrete elements in acidic entrainments, but field trials are still needed to further verify their performance.
Download or read book Response of Concrete to Incremental Aggression of Sulfuric Acid written by M. H. Mahmoud and published by . This book was released on 2020 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt: There is lack of standardized tests for specifically evaluating the resistance of concrete to sulfuric acid attack, which has caused great variability, for example, in terms of solution concentration, pH level/control, etc., among previous studies in this area. Accordingly, there are conflicting data about the role of key constituents of concrete (e.g., supplementary cementitious materials [SCMs]) and uncertainty about building codes' stipulations for concrete exposed to sulfuric acid. Hence, the aim of this study was to assess the behavior of the same concretes, prepared with single and blended binders, to incremental levels (mild, severe, and very severe) of sulfuric acid solutions over 36 weeks. The test variables included the type of cement (general use [GU] or portland limestone cement [PLC]) and SCMs (fly ash, silica fume, and nanosilica). The severe (1 %, pH of 1) and very severe aggression (2.5 %, pH of 0.5) phases caused mass loss of all specimens, with the latter phase providing clear distinction among the performance of concrete mixtures. The results showed that the penetrability of concrete was not a controlling factor under severe and very severe damage by sulfuric acid attack, whereas the chemical vulnerability of the binder was the dominant factor. Mixtures prepared from the PLC performed better than those prepared from GU. While the quaternary mixtures that consisted of GU or PLC, fly ash, silica fume, and nanosilica showed the highest mass losses after 36 weeks, the binary mixtures incorporating GU or PLC with fly ash had the lowest mass losses.
Download or read book Performance of Cement Based Materials in Aggressive Aqueous Environments written by Mark Alexander and published by Springer Science & Business Media. This book was released on 2012-12-18 with total page 471 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Effects of Substances on Concrete and Guide to Protective Treatments written by and published by . This book was released on 1981 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Pozzolanic and Cementitious Materials written by V.M. Malhotra and published by CRC Press. This book was released on 2004-11-11 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume provides an overview of the mineral admixtures used in concrete, including silica fume, slag, rice-husk ash, fly ash and natural pozzolans. It also includes the mineral/chemical composition of the admixtures, their chemical reactions with cement and as a method of recycling.
Download or read book ACI Manual of Concrete Practice written by American Concrete Institute and published by . This book was released on 2002 with total page 996 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Cement Production Technology written by Anjan Kumar Chatterjee and published by CRC Press. This book was released on 2018-04-27 with total page 484 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book is an outcome of the author’s active professional involvement in research, manufacture and consultancy in the field of cement chemistry and process engineering. This multidisciplinary title on cement production technology covers the entire process spectrum of cement production, starting from extraction and winning of natural raw materials to the finished products including the environmental impacts and research trends. The book has an overtone of practice supported by the back-up principles.
Download or read book Design and Control of Concrete Mixtures written by Steven H. Kosmatka and published by . This book was released on 1988 with total page 224 pages. Available in PDF, EPUB and Kindle. Book excerpt: Portland Cement Association reference, dealing with fundamentals, cold weather concreting, curing, admixtures, aggregates, mixing, and much more.
Download or read book Advances in Structural Engineering written by Vasant Matsagar and published by Springer. This book was released on 2014-12-12 with total page 1033 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book presents research papers presented by academicians, researchers, and practicing structural engineers from India and abroad in the recently held Structural Engineering Convention (SEC) 2014 at Indian Institute of Technology Delhi during 22 – 24 December 2014. The book is divided into three volumes and encompasses multidisciplinary areas within structural engineering, such as earthquake engineering and structural dynamics, structural mechanics, finite element methods, structural vibration control, advanced cementitious and composite materials, bridge engineering, and soil-structure interaction. Advances in Structural Engineering is a useful reference material for structural engineering fraternity including undergraduate and postgraduate students, academicians, researchers and practicing engineers.
Download or read book Failure Distress and Repair of Concrete Structures written by Norb Delatte and published by Elsevier. This book was released on 2009-10-26 with total page 352 pages. Available in PDF, EPUB and Kindle. Book excerpt: Understanding and recognising failure mechanisms in concrete is a fundamental pre-requisite to determining the type of repair, or whether a repair is feasible. This title provides a review of concrete deterioration and damage, as well as looking at the problem of defects in concrete. It also discusses condition assessment and repair techniques.Part one discusses failure mechanisms in concrete and covers topics such as causes and mechanisms of deterioration in reinforced concrete, types of damage in concrete structures, types and causes of cracking and condition assessment of concrete structures. Part two reviews the repair of concrete structures with coverage of themes such as standards and guidelines for repairing concrete structures, methods of crack repair, repair materials, bonded concrete overlays, repairing and retrofitting concrete structures with fiber-reinforced polymers, patching deteriorated concrete structures and durability of repaired concrete.With its distinguished editor and international team of contributors, Failure and repair of concrete structures is a standard reference for civil engineers, architects and anyone working in the construction sector, as well as those concerned with ensuring the safety of concrete structures. - Provides a review of concrete deterioration and damage - Discusses condition assessment and repair techniques, standards and guidelines
Download or read book Sulfate Attack on Concrete written by J. Marchand and published by CRC Press. This book was released on 2001-10-11 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sulfate Attack on Concrete provides a comprehensive reference to this important subject. It covers: a short history of concrete deterioration due to sulfate attack, the origin of sulfates in concrete, the importance of appropriate concrete processing, forms and physical-chemical mechanisms of concrete deterioration due to sulfates, preventative mea
Download or read book Oil Shales and Tar Sands written by United States. Department of Energy and published by . This book was released on 1977 with total page 752 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Guide to the Selection and Use of Hydraulic Cements written by American Concrete Institute and published by . This book was released on 1999 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Guide to Durable Concrete written by ACI Committee 201 and published by . This book was released on 1977 with total page 37 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Deteriorated Concrete written by Frank Rendell and published by Thomas Telford. This book was released on 2002 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt: - 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
Download or read book CRC Handbook of Metal Etchants written by Perrin Walker and published by CRC Press. This book was released on 1990-12-11 with total page 1434 pages. Available in PDF, EPUB and Kindle. Book excerpt: This publication presents cleaning and etching solutions, their applications, and results on inorganic materials. It is a comprehensive collection of etching and cleaning solutions in a single source. Chemical formulas are presented in one of three standard formats - general, electrolytic or ionized gas formats - to insure inclusion of all necessary operational data as shown in references that accompany each numbered formula. The book describes other applications of specific solutions, including their use on other metals or metallic compounds. Physical properties, association of natural and man-made minerals, and materials are shown in relationship to crystal structure, special processing techniques and solid state devices and assemblies fabricated. This publication also presents a number of organic materials which are widely used in handling and general processing...waxes, plastics, and lacquers for example. It is useful to individuals involved in study, development, and processing of metals and metallic compounds. It is invaluable for readers from the college level to industrial R & D and full-scale device fabrication, testing and sales. Scientific disciplines, work areas and individuals with great interest include: chemistry, physics, metallurgy, geology, solid state, ceramic and glass, research libraries, individuals dealing with chemical processing of inorganic materials, societies and schools.
