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Webinar Description:
Simple temperature measurements of
hydrating concrete, mortar, or paste mixtures (referred to as semi-adiabatic
calorimetry or SAC) has become a powerful QC tool for ready-mixed concrete
producers. Hydrating concrete materials generate heat, and the profile of
the resulting thermal history can provide a useful indication of setting
time, early hydration efficiency, and various other aspects of performance.
Available equipment for SAC testing now includes convenient manufactured
systems as well as generic temperature monitoring hardware and data loggers
that can be adapted for the purpose. Testing involves the use of such
equipment / systems to collect and record the changing temperatures of
hydrating mixtures, usually for no more than 24 hours, then plotting the
data in groups of "thermal profiles" for comparative analysis. This can be
done in the field with job-sampled concrete, at the ready-mix plant with
fresh or wet-sieved concrete, or in the lab with small paste or mortar
batches that simulate proposed concrete proportions and field temperatures.
Some of the key performance effects of different mixture variables can
easily be explored in a small fraction of the time that would be required
for lab concrete batches.
Specific SAC applications of interest to the ready-mixed concrete producer
include evaluating the setting time influences of changes in admixtures,
dosage rates, cementitious component proportions, and mixture temperatures;
tracking materials variability in routine SAC testing for QC; comparing
candidate materials or sources in typical mixture proportions; verifying
seasonal adjustments to mixtures; and troubleshooting abnormal hydration
behavior or "incompatibility" tendencies that cause certain concrete field
problems.
This webinar will introduce the participants to SAC equipment, methods, and
applications, and will cover the basics of how to plan and conduct an
effective SAC testing program. Interpretation of SAC thermal profiles will
be discussed and case history examples of SAC QC and troubleshooting
applications will be presented.
Presenter Bio:
Tim Cost (PE, FACI) has over 33 years of
professional experience relating to cementitious materials, concrete, and
related applications. For 10 years prior to joining Holcim (then Holnam) in
1996, Mr. Cost represented the concrete industry in Mississippi, including
the Portland Cement Association and the Mississippi Concrete Industries
Association (MCIA), where he was Executive Director from 1990 through 1995.
For the previous 10 years he was involved with research work relating to
concrete structures at the US Army Corps of Engineers Waterways Experiment
Station (now Engineer Research and Development Center).
His expertise
includes concrete pavements, cementitious materials, concrete durability,
cement-admixture interaction, soil stabilization, and other areas of cement
and concrete technology.
Mr. Cost is a Fellow of the American Concrete Institute (ACI) and is active
in various other professional organizations and industry trade associations
nationally and in several states, including ASCE, NSPE, ASTM, and ACPA
(American Concrete Pavement Association). He is a member of the ACPA
Technical Committee and Streets and Local Roads Committee. He chairs ACI
committee 330 for Concrete Parking Lots and Site Paving, and is an active
member of committees 230 (Soil Cement), 325 (Concrete Pavements), 211
(Concrete Mixture Proportioning), 302 (Construction of Concrete Floors), and
360 (Design of Slabs on Ground). He is active on ASTM Committees C1 (Cement)
and C9 (Concrete and Concrete Aggregates) and leads a Task Group of
Subcommittee C01/09.48 (Performance of Cementitious Materials and Admixture
Combinations). He is an instructor and examiner for ACI concrete technician
and finisher certification programs and is past president of the ACI
Mid-South Chapter. He has served as a seminar instructor for ACI
International and the CONEXPO/CON-AGG trade show.
His education includes a B.S. and graduate studies in civil engineering from
Mississippi State University. He is a registered Professional Engineer in
Mississippi.
