Improving Portland Cement Concrete Mix Consistency and Production Rate through Two-Stage Mixing
Author: Tyson D. Rupnow, Vernon R. Schaefer, Kejin Wang, Benjamin L Hermanson | Size: 4.5 MB | Format:PDF | Publisher: National Concrete Pavement Technology Center | Year: 2007 | pages: 98
Abstract:
A two-stage mixing process for concrete involves mixing a slurry of cementitious materials and water, then adding the slurry to coarse and fine aggregate to form concrete. Some research has indicated that this process might facilitate dispersion of cementitious materials and improve cement hydration, the characteristics of the interfacial transition zone (ITZ) between aggregate and paste, and concrete homogeneity. The goal of the study was to find optimal mixing procedures for production of a homogeneous and workable mixture and quality concrete using a two-stage mixing operation. The specific objectives of the study are as follows: (1) To achieve optimal mixing energy and time for a homogeneous cementitious material, (2) To characterize the homogeneity and flow property of the pastes, (3) To investigate effective methods for coating aggregate particles with cement slurry, (4) To study the effect of the two-stage mixing procedure on concrete properties, (5) To obtain the improved production rates. Parameters measured for Phase I included: heat of hydration, maturity, and rheology tests were performed on the fresh paste samples, and compressive strength, degree of hydration, and scanning electron microscope (SEM) imaging tests were conducted on the cured specimens. For Phases II and III tests included slump and air content on fresh concrete and compressive and tensile strengths, rapid air void analysis, and rapid chloride permeability on hardened concrete.
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Author: Sue Roaf, Manuel Fuentes, Stephanie Thomas | Size: 6.16 MB | Format:PDF | Publisher: Elsevier | Year: 2001 | pages: 353 | ISBN: 0 7506 4904 6
Editorial Reviews
Review
'It's great to read a book with a no-nonsense message'
The Architectural Review
'Sue Roaf has been able to show wonderful examples of climate-sensitive design from around the world. She addresses the architectural issues head on. The book is a good read, wonderfully illustrated and full of inspiration for the eco-enthusiast or self builder.'
5-star Amazon customer review
'At no time did I feel that the presentation was dry; the text is well supported by diagrams, photographs and technical drawings...The information is never less than practical and so far I have not come across a better way to grasp the subtleties and contradictions of what makes an ecohouse.'
5-star Amazon customer review
'I was prepared to find some of the sections a bit too techie, but in fact was riveted from start to finish. Very well written throughout and the case studies are fantastic.'
5-star Amazon customer review
'One of the best reference guides to the issues in designing an ecohome.'
The Lecturer
Book Description
New edition of this popular "how to" guide includes the latest on environmentally friendly design --This text refers to an alternate Paperback edition.
Product Description
Ecohouse is an exciting and timely text that tells you how to design low energy, environmentally friendly buildings today. It also provides the foundations for building design in a warming world, and stepping stones towards the zero-carbon emission buildings of tomorrow.
Sue Roaf is famed for her approach to design and her awareness of energy efficiency. Here she reveals the concepts, structures and techniques that lie behind the realization of her ideals. By using her own house as a case-study Roaf guides the reader through the ideas for energy efficient design or 'eco design'.
This guide to the ecohouse also explores 21 case-studies from around the world, from Norway and Sweden to India and Japan, Argentina and Mexico. Chapters by Christopher Day, Katerine Bohn and Andre Viljoen on ecological building materials and methods and a contribution by Robert and Brenda Vale - all experts in this field
Ecohouse has a regularly updated companion web site providing further information on all issues relating to Ecohouse and eco design. Log on to www.bh.com/companions/ecohouse for a direct link.
* Learn about the key issues of form and construction in Eco house design
* Gain an understanding of building materials and their energy and environmental impacts - now essential for both student and practitioner
* Theory is shown in practice with 21 case-studies from around the world
From the Publisher
Sue Roaf is famed for her approach to design and her awareness of energy efficiency. Here she reveals the concepts, structures and techniques that lie behind the realization of her ideals. By using her own house as a case-study Roaf guides the reader through the ideas for energy efficient design or 'eco design'.This guide to the ecohouse also explores 21 case-studies from around the world, from Norway and Sweden to India and Japan, Argentina and Mexico. Chapters by Christopher Day, Katerine Bohn and Andre Viljoen on ecological building materials and methods and a contribution by Robert and Brenda Vale - all experts in this fieldEcohouse has a regularly updated companion web site providing further information on all issues relating to Ecohouse and eco design.
From the Back Cover
This second edition of the Ecohouse design guide outlines the key issues, strategies and design solutions for designers and self-builders who want to build low energy, low impact homes.
At a time when fossil fuel energy prices are soaring and the impacts of climate change are beginning to bite, no one should begin to design a 21st century house without understanding the lessons of this timely and exciting book.
Hot topics covered include materials, insulation, thermal mass, natural ventilation, infiltration, solar design systems and water conservation. --This text refers to an alternate Paperback edition.
About the Author
Sue Roaf is Professor of Architectural Engineering at Heriot Watt University and Visiting Professor at the Open University. She publishes widely on traditional; technologies, sustainable buildings, ecohouse design and adapting buildings and cities for climate change. She designed and lives in the Oxford Ecohouse, the first UK building with a photovoltaic roof and does much to promote resilient low impact buildings through the conferences she organises on Solar Cities, Carbon Counting, Architectural Education, Thermal Comfort and Post Occupancy Evaluation. She is currently co-chairing the Westminster and Scottish Carbon Accounting Groups with Colin Challen MP and Sarah Boyak MSP.
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Posted by: ir_71 - 11-20-2010, 05:44 AM - Forum: ISO
- Replies (2)
ISO 17635:2010 Non-destructive testing of welds - General rules for metallic materials
Author: ISO TC 121 | Size: 1.5 MB | Format:PDF | Publisher: ISO | Year: 2010 | pages: 22
This International Standard gives guidelines for the choice of non-destructive testing (NDT) methods for welds
and evaluation of the results for quality control purposes, based on quality requirements, material, weld
thickness, welding process, and extent of testing.
This International Standard also specifies general rules and standards to be applied to the different types of
testing, for either the methodology or the acceptance level for metallic materials.
Acceptance levels cannot be a direct interpretation of the quality levels defined in ISO 5817 or ISO 10042.
They are linked to the overall quality of the produced batch of welds.
Requirements for acceptance levels for NDT comply with quality levels stated in ISO 5817 or ISO 10042
(moderate, intermediate, stringent) only on a general basis and not in detail for each indication.
Annex A gives correlations between quality, NDT and acceptance level standards.
Annex B gives an overview of the standards linked to quality levels, acceptance levels, and NDT methods.
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Simplified Computations for Effective Moment of Inertia Ie and Minimum Thickness to Avoid Deflection Computations
Author: Jacob S. Grossman | Size: 1.51 MB | Format:PDF | Year: 1981 | Publisher: ACI JOURNAL, Proceedings V. 78, No. 6, Nov.-Dec. 1981, pp. 423-439.
An approximate simplified procedure is described for estimating the effective moment of inertia I, for beams, T-beams, or one-way slabs constructed of normal weight aggregate concrete or lightweight concrete, and reinforced with 40-80 ksi reinforcing bars. The results are compatible with Ie values obtained from Eq. (9-7) of ACI 318-77. The simplified equations do not require computations for moment of inertia of the cracked section Icr, nor the reinforcing requirements initially. Also described is a simplified procedure for establishing minimum member depth so that deflection computations to ascertain serviceability may be avoided when designing the majority of one-way members
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Semi-active versus passive or active tuned mass dampers for structural control
Hrovat D, Barak P, Rabins M.
Journal of Engineering Mechanics 1983;109(3):691–705.
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Shell structures are found abundantly in engineering designs and are routinely analysed with finite element methods. The objective of this book is to present, in a unified manner, modern finite element procedures for general shell analysis. The first chapters introduce the basic concepts for the analysis of shells, explain the mathematical preliminaries, and discuss the mathematical models of plates and shells including their asymptotic properties. The following chapters deal with finite element discretization methods for plates and shells. At the end of the book, applications of these methods in modern engineering practice are described and an overview of nonlinear shell analysis is given.
Review
From the reviews:
"The major part of the book focuses on the linear analysis of shell structures, for which a discussion of the available mathematical models and discretization procedures is given. … The aim of the present volume is to provide more powerful finite element methods by a deeper physical understanding of shell structural behavior and application of stronger mathematical theories. … This well-written text is not just a survey of finite element methods for shell analyses, but presents the authors’ experiences with shell analysis methods." (K.Marti, ZAMM - Zeitschrift für Angewandte Mathematik und Mechanik, Vol. 85 (2), 2005)
"If we are aware of the rising application of finite shell elements in industrial applications and of the growing size of the problems, an increase of mathematical knowledge for element use and development seems to be required. Just this is the aim of the present book … . This book is recommended to all ‘applied mechanicians’, who intend to study the mathematical backgrounds of finite shell analyses. For all developers of advanced and more powerful finite shell element techniques, its reading is a ‘must’." (Technische Mechanik, Vol. 24 (1), 2004)
"The main objective is to combine the fundamentals of shell theories, mathematical analyses and finite element methods in order to develop shell finite element approximations which are reliable and effective. … The expertises of both authors combined with a very clear and attractive presentation lead to a wonderful masterpiece which is, with no doubt and for a long time, the great reference book for the development of accurate and reliable numerical methods in the thin shell world." (Michel Bernadou, Zentralblatt MATH, Vol. 1103 (5), 2007)
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Author: John M Biggs | Size: 8,447 KB | Format:PDF | Publisher: New York, McGraw-Hill | Year: 1964
One of the best books in the field of structural dynamics
Contents:
01. Numerical Analysis of Simple Systems
02. Rigorous Analysis of One-degree Systems
03. Lumped-mass Multidegree Systems
04. Structures with Distributed Mass and Load
05. Approximate Design Methods
06. Earthquake Analysis and Design
07. Blast-resistant Design
08. Beams Subjected to Moving Loads
Hope it would be useful for someone
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