In todayโs market, it is imperative to be knowledgeable and have an edge over the competition. ACI members have itโฆthey are engaged, informed, and stay up to date by taking advantage of benefits that ACI membership provides them.
Read more about membership
Learn More
Become an ACI Member
Founded in 1904 and headquartered in Farmington Hills, Michigan, USA, the American Concrete Institute is a leading authority and resource worldwide for the development, dissemination, and adoption of its consensus-based standards, technical resources, educational programs, and proven expertise for individuals and organizations involved in concrete design, construction, and materials, who share a commitment to pursuing the best use of concrete.
Staff Directory
ACI World Headquarters 38800 Country Club Dr. Farmington Hills, MI 48331-3439 USA Phone: 1.248.848.3800 Fax: 1.248.848.3701
ACI Middle East Regional Office Second Floor, Office #207 The Offices 2 Building, One Central Dubai World Trade Center Complex Dubai, UAE Phone: +971.4.516.3208 & 3209
ACI Resource Center Southern California Midwest Mid Atlantic
Feedback via Email Phone: 1.248.848.3800
ACI Global Home Middle East Region Portal Western Europe Region Portal
Home > Tools > Frequently Asked Questions
Q. How is concrete consolidated? A. The consolidation method should be compatible with the concrete mixture, placing conditions, form intricacy, and amount of reinforcement. Methods of consolidation are explained in ACI 309R. Some consolidation is caused by gravity as the concrete is deposited in the form. This is particularly true for well-proportioned flowing mixtures where less additional consolidation effort is required. Self-consolidating concretes provide the necessary properties without the need for additional consolidation effort. The manual consolidation methods are generally used only on smaller nonstructural concrete placement. Plastic or more flowable mixtures may be consolidated by rodding. Spading— in which a flat tool is repeatedly inserted and withdrawn adjacent to the form—is sometimes used at formed surfaces. Hand tamping may be used to consolidate stiff mixtures. The most widely used consolidation method is vibration. Vibration can be internal, external, or both. Vibration consists of subjecting freshly placed concrete to rapid vibratory impulses that liquefy the mortar and drastically reduce the internal friction between aggregate particles. While in this condition, concrete settles under the action of gravity (sometimes aided by other forces). When vibration is discontinued, friction is reestablished (ACI 309R). References: SP-1(02); ACI PRC-309.5-22; ACI PRC-237.2-21 Topics in Concrete: Concrete Fundamentals; Consolidation of Concrete; Placing Concrete
Q. How is concrete consolidated?
A. The consolidation method should be compatible with the concrete mixture, placing conditions, form intricacy, and amount of reinforcement. Methods of consolidation are explained in ACI 309R. Some consolidation is caused by gravity as the concrete is deposited in the form. This is particularly true for well-proportioned flowing mixtures where less additional consolidation effort is required. Self-consolidating concretes provide the necessary properties without the need for additional consolidation effort.
The manual consolidation methods are generally used only on smaller nonstructural concrete placement. Plastic or more flowable mixtures may be consolidated by rodding. Spading— in which a flat tool is repeatedly inserted and withdrawn adjacent to the form—is sometimes used at formed surfaces. Hand tamping may be used to consolidate stiff mixtures. The most widely used consolidation method is vibration. Vibration can be internal, external, or both. Vibration consists of subjecting freshly placed concrete to rapid vibratory impulses that liquefy the mortar and drastically reduce the internal friction between aggregate particles. While in this condition, concrete settles under the action of gravity (sometimes aided by other forces). When vibration is discontinued, friction is reestablished (ACI 309R).
References: SP-1(02); ACI PRC-309.5-22; ACI PRC-237.2-21
Topics in Concrete: Concrete Fundamentals; Consolidation of Concrete; Placing Concrete
Search other resources on the ACI website for answers to technical questions