"This report presents a recommended procedure for evaluating air-entraining admixtures used in highway concrete. The procedure involves the testing of non-air-entrained concrete and concrete containing the air-entraining admixture under simulated field conditions. Criteria are proposed for acceptance of admixtures for use in either highway pavements or structures. The recommended procedure and acceptance criteria will guide materials engineers in evaluating and selecting air-entraining admixtures that should contribute to appropriate freeze-thaw durability and thus to good performance and long service life. The content of the report will be of immediate interest to materials engineers, researchers, and others concerned with the design of concrete mixtures for use in highway pavements and structures."--taken from Foreword, page [v].
"TRB's National Cooperative Highway Research Program (NCHRP) 749: Methods for Evaluating Fly Ash for Use in Highway Concrete presents suggested changes to coal fly ash specifications and test protocols contained in American Association of State Highway and Transportation Officials (AASHTO) Standard Specifications for Transportation Materials and Methods of Sampling and Testing (AASHTO M 295). The changes suggested include modifications to the test methods currently specified for evaluating acceptability of fly ash for use in highway concrete as well as the introduction of new test methods for enhancing such evaluations. Attachment C: Details of the Research into Methods for Evaluating Fly Ash Use in Highway Concrete is only available online."--Publisher description.
This study evaluated the impacts of construction on the air content and air-void system structure of Portland cement concrete pavements. The primary intent was to quantify the air content of fresh concrete before and after it has gone through the slipform paver. The air-void system parameters of hardened concrete were then assessed using cast and extracted core specimens. The results of the air content testing on fresh concrete and the concrete cylinder specimens cast in the field suggested that there is some loss of air as the concrete passes through the paver. Laboratory testing performed on cores extracted from the pavement did not provide any conclusive evidence that entrained air is lost during the slipform paving process. In fact, many of the extracted cores had measured air content values that were much higher than the specification requirement. If excessive, this could result in increased permeability and low-strength related issues. Although a rigorous statistical analysis was not performed, the results suggest that the air content testing on fresh concrete is not capturing the true air content of the concrete placed with a slipform paver. The fresh concrete air content is generally lower than the air content measured in the cores.
Science and Technology of Concrete Admixtures presents admixtures from both a theoretical and practical point-of-view. The authors emphasize key concepts that can be used to better understand the working mechanisms of these products by presenting a concise overview on the fundamental behavior of Portland cement and hydraulic binders as well as their chemical admixtures, also discussing recent effects in concrete in terms of rheology, mechanics, durability, and sustainability, but never forgetting the fundamental role played by the water/binder ratio and proper curing in concrete technology. Part One presents basic knowledge on Portland cement and concrete, while Part Two deals with the chemical and physical background needed to better understand what admixtures are chemically, and through which mechanism they modify the properties of the fresh and hardened concrete. Subsequent sections present discussions on admixtures technology and two particular types of concrete, self-consolidating and ultra-high strength concretes, with final remarks on their future. - Combines the knowledge of two leading authors to present both the scientific and technology of admixtures - Explains what admixtures are from a chemical point-of-view and illustrates by which mechanisms they modify the properties of fresh and hardened concrete - Presents a fundamental, practical, and innovative reference book on the topic - Contains three detailed appendices that can be used to learn how to use admixtures more efficiently
Construction Calculations is a manual that provides end users with a comprehensive guide for many of the formulas, mathematical vectors and conversion factors that are commonly encountered during the design and construction stages of a construction project. It offers readers detailed calculations, applications and examples needed in site work, cost estimation, piping and pipefitting, and project management. The book also serves as a refresher course for some of the formulas and concepts of geometry and trigonometry. The book is divided into sections that present the common components of construction. The first section of the books starts with a refresher discussion of unit and systems measurement; its origin and evolution; the standards of length, mass and capacity; terminology and tables; and notes of metric, U.S, and British units of measurements. The following concepts are presented and discussed throughout the book: Conversion tables and formulas, including the Metric Conversion Law and conversion factors for builders and design professionals Calculations and formulas of geometry, trigonometry and physics in construction Rudiments of excavation, classification, use of material, measurement and payment Soil classification and morphology, including its physicochemical properties Formulas and calculations needed for soil tests and evaluations and for the design of retaining structures Calculations relating to concrete and masonry Calculations of the size/weight of structural steel and other metals Mechanical properties of wood and processing of wood products Calculations relating to sound and thermal transmission Interior finishes, plumbing and HVAC calculations Electrical formulas and calculations Construction managers and engineers, architects, contractors, and beginners in engineering, architecture, and construction will find this practical guide useful for managing all aspects of construction. - Work in and convert between building dimensions, including metric - Built-in right-angle solutions - Areas, volumes, square-ups - Complete stair layouts - Roof, rafter and framing solutions - Circle: arcs, circumference, segments
One of the most pressing problems facing the construction industry globally is the deterioration of major concrete infrastructure in marine and other chloride-containing environments. While recent advancements in concrete technology have made it easier to control the negative impact of deteriorating processes such as alkali-aggregate reaction, free
