Print this page Concrete Admixtures
John Poullain, P.E.
Course Outline
This two-hour online course discusses commonly used chemical admixtures for concrete and describes their basic uses. Concrete can usually be made with the desirable qualities of being workable, durable and strong by using suitable materials without admixtures. Admixtures however are used to improve the quality of concrete during mixing, transporting, placement, curing and to achieve certain properties. The course text can serve as a reference. The admixtures discussed include air entraining, water reducing, set retarding, and specialty admixtures.
In this course, the student will cover these topics:
- Major reasons for using admixtures.
- Functions, categories and types of admixtures.
- Factors that determine their effectiveness.
- ASTM and AASHTO publications to check for an admixture.
- Expected benefits to conventional concrete by using the admixtures.
- Fundamental qualities of concrete.
- Factors to consider for the quality and placement of concrete.
This course includes a multiple-choice quiz at the end, which is designed to enhance the understanding of the course materials.
Learning Objective
In this course, the student will cover these topics:
- Major reasons for using admixtures.
- Functions, categories and types of admixtures;
- Factors that determine their effectiveness;
- ASTM and AASHTO publications to check for an admixture;
- Expected benefits to conventional concrete by using the admixtures;
- Fundamental qualities of concrete; and
- Factors to consider for the quality and placement of concrete.
Intended Audience
This course should benefit civil engineers, pavement engineers, transportation engineers, field and office personnel, supervisors and maintenance personnel.
Benefit to Attendees
The student will become familiar with commonly used chemical admixtures for concrete and describes their basic uses
Course Introduction
Admixtures have long been used to improve the performance of concrete. Earlier materials used included organic matter such as milk and lard by the Romans and rice paste and blackstrap molasses by the Chinese. The ACI defines concrete admixtures as “a material other than water, aggregates, hydraulic cement, and fiber reinforcement, used as an ingredient of a cementitious mixture to modify its freshly mixed, setting, or hardened properties and that is added to the batch before or during its mixing.” Concrete properties may be modified to increase compressive and flexural strength, to improve durability, inhibit corrosion, reduce shrinkage, accelerate or retard initial set among the many uses. Desirable qualities of concrete, workability, finishability, and wear resistance can often be achieved by using suitable materials. However to achieve certain properties, and maintain quality during mixing, curing in adverse conditions or emergencies, admixtures become necessary.
Course Content
The course is based on the PCA publication “Design and Control of Concrete Mixes”, Chapters 1 and 6, (2004 Edition, 33 pages), PDF file.
Design and Control of Concrete Mixes Chapter 1
Design and Control of Concrete Mixes Chapter 6
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Course Summary
This course should serve as a guide to assist pavement engineers, field personnel and others. The course discusses the functions, types and reasons for using admixtures. Factors to consider for selecting admixtures to achieve the desired qualities, the results and any potential adverse combinations to avoid are described.
Related Links
For additional technical information related to this subject, please refer to:
http://www.nrmca.org/aboutconcrete/cips/15p.pdf
NRMCA publication summarizes the common admixtures, describes what they are and how they are used.
Quiz
Once you finish studying the above course content, you need to take a quiz to obtain the PDH credits.
DISCLAIMER: The materials contained in the online course are not intended as a representation or warranty on the part of PDH Center or any other person/organization named herein. The materials are for general information only. They are not a substitute for competent professional advice. Application of this information to a specific project should be reviewed by a registered architect and/or professional engineer/surveyor. Anyone making use of the information set forth herein does so at their own risk and assumes any and all resulting liability arising therefrom.
