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Webinar Description:
Concreting in cold weather provides a
variety of challenges during production, delivery and installation and
subsequent protection of concrete. The advantages of cold weather concreting
include less chance of rapid slump loss or setting, buying more time for
transport and placement. Better yet, optimum later-age concrete strength can
be attained at lower curing temperatures. The downside is that setting can
be prolonged too much, evaporation can be more severe, and the slow rate of
early-age strength gain can delay form and shore removal, or application of
prestressing forces or construction loads. Although freezing of unprotected
concrete is always a threat, we need to understand that the early-age
strength gain is a real problem at concrete temperatures that are 20 degrees
warmer than freezing.
Program Elements Include:
Why concrete behavior is influenced by
temperature: hydration, slump-loss, setting, and strength gain.
Why evaporation and drying can be more
severe in winter than summer.
Why we are concerned about strength at
temperatures 20 degrees warmer than freezing.
Industry guidance and requirements for
concreting in cold weather
Methods to produce concrete at required
temperature
Precautions during construction in cold weather
Presenter Bio:
Kenneth
C. Hover is a Professor of Civil & Environmental Engineering and Stephen
Weiss Presidential Fellow at Cornell University in Ithaca, New York. An ACI
Member since 1980, Ken is Past President of the Greater Miami Valley Chapter
of ACI, and a member of ACI Committees 305 (hot weather), 306 (cold
weather), 308 (curing), 318A (concrete and construction) and chair of 301C
(materials and construction). Ken is currently Vice President of the
American Concrete Institute, and will become President in March, 2011.
He served as a Captain in the Army Corps of Engineers (15th Combat Engineer
Battalion), and was Project Engineer and Project Manager for Dugan and
Meyers Construction Co. in Cincinnati, working on buildings, interstate
bridges, and water treatment plants. Joining the structural consulting firm
of THP Ltd in Cincinnati, he became a partner and manager with experience in
project design, specifications writing, design team management, and contract
administration. He holds Bachelors and Masters Degrees in Civil Engineering
from the University of Cincinnati, and earned the Ph.D. in Structural
Engineering from Cornell University.
Ken came to Cornell with the assistance of a grant from the Exxon
Foundation, designed to bring experienced engineers to the faculties of US
Colleges of Engineering, and was among the first winners of an ACI
Scholarship. He joined the faculty in 1984 where he teaches reinforced and
prestressed concrete design, concrete materials, and construction
management. His research focuses on the impact of construction operations
and the construction environment on concrete quality.
Ken is a registered professional engineer in Ohio and New York, and lectures
nationally and internationally on concrete materials and construction. He
holds the Outstanding Educator Award from the American Concrete Pavement
Association, and from ACI he has earned the Kelly Educator’s Award, Philleo
Research Award, Structural Research Award, and Arthur Anderson Award. He
also received the ASCE Materials Division’s Best Basic Research Paper Award.
The Weiss Presidential Fellowship is Cornell University’s highest teaching
award, and in January 2006 at World of Concrete he was named one of the “Ten
Most Influential People in the Concrete Industry.”