Email Address is required Invalid Email Address
In today’s market, it is imperative to be knowledgeable and have an edge over the competition. ACI members have it…they 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
Home > Tools > Frequently Asked Questions
Q. What are false set and flash set? A. False set is the rapid development of rigidity in freshly mixed paste, mortar, or concrete without the evolution of much heat. Plasticity can be regained by further mixing. Flash set is also the rapid development of rigidity, but with the evolution of considerable heat. Plasticity cannot be regained. Rapid development of rigidity would interfere with delivery and placement operations. Flash set would make concrete unusable, and concrete hardened in the mixer could not be removed easily. References: SP-1(02); ACI Physical Testing of Cement Training Video; ASTM C403; ASTM C191; ASTM C266; ASTM C953 Topics in Concrete: Concrete Fundamentals
Q. What are false set and flash set?
A. False set is the rapid development of rigidity in freshly mixed paste, mortar, or concrete without the evolution of much heat. Plasticity can be regained by further mixing. Flash set is also the rapid development of rigidity, but with the evolution of considerable heat. Plasticity cannot be regained. Rapid development of rigidity would interfere with
delivery and placement operations. Flash set would make concrete unusable, and concrete hardened in the mixer could not be removed easily.
References: SP-1(02); ACI Physical Testing of Cement Training Video; ASTM C403; ASTM C191; ASTM C266; ASTM C953
Topics in Concrete: Concrete Fundamentals
Search other resources on the ACI website for answers to technical questions