High ambient temperature, high concrete temperature, low relative humidity, and high wind speed can damage both fresh mixed and hardened concrete.

The American Concrete Institute highlights how “…concrete in hot weather is subject to high loss of moisture by evaporation and rapid hardening, which affect the placement operations and the cracking potential.” Further, weather events and environmental conditions such as high ambient temperature, high concrete temperature, low relative humidity, and high wind speed can damage both fresh mixed and hardened concrete — leading to acceleration of the rate of moisture loss and cement hydration. ACI explains that no single maximum ambient or concrete temperature exists, but a concrete temperature of between 75°F and 100°F yields the best results.

The American Concrete Institute (ACI, www.concrete.org) webinar “Proportioning & Testing Concrete Mixtures for Hot Weather” addresses the challenges of hot weather concreting. The webinar is lead by Phil Brandt, Terry Harris and Tarek Khan, and approved by the AIA and the ICC. The webinar discusses the definition of hot weather, summarizes the challenges caused by hot weather, and describes concrete techniques for hot weather. ACI categories include: construction practices, curing, hot weather, and mixture proportioning. ACI also offers numerous other courses, publications, specifications and guides on hot weather.

“Proportioning & Testing Concrete Mixtures for Hot Weather” Learning Objectives

  1. Discuss the definition of hot weather
  2. Summarize challenges caused by hot weather
  3. Describe how to use admixtures, supplementary cementitious materials, synthetic fibers and other mixture proportioning techniques for hot weather
  4. Explain the importance of proper testing, monitoring and curing of concrete, in particular test specimens, for a successful project in hot weather
  5. Review of case studies involving the successful placement of concrete during hot weather

Other ACI On-Demand Courses on Hot Weather

  • Hot Weather Concrete – Best Practices and Lessons Learned
  • 305.1-14 Updates to Hot Weather Concrete Specification
  • Guide to Hot Weather Concreting: Chapter 5 Production and Delivery; Chapter 6 Placing and Curing

ACI Publications on Hot Weather

  • ACI 305.1-14(20) Specification for Hot Weather Concreting (Reapproved 2020)
  • ACI 305R-10 Guide to Hot Weather Concreting
  • Durable Concrete in Hot Climates (SP-139)

About ACI Committee 305 – Hot Weather Concreting

The ACI Committee 305 – Hot Weather Concreting Committee mission is to “develop and report information on hot weather concreting.” Goals include to “publish in 2016 revisions to Guide to Hot Weather Concreting (ACI 305R-10) with current technology and include reference sections to support Specification for Hot Weather Concreting (ACI 305.1-06) and add a section on sustainability,” and to publish a Spanish translation of the Guide to Hot Weather Concreting.

About ACI

Founded in 1904 and headquartered in Farmington Hills, Michigan, USA, and a regional office in Dubai, UAE, the American Concrete Institute is a leading authority and resource worldwide for the development, dissemination, and adoption of its consensus-based standards, technical resourceseducational & training programscertification 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. ACI has more than 100 chapters, 215 student chapters, and 30,000 members spanning over 120 countries.

For a complete listing of ACI resources on concrete cracking including: journal articles, news items, and frequently asked questions visit the ACI Topics in Concrete page.

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