Service Life Prediction Based on Sorptivity for Highway Concrete Exposed to Sulfate Attack and Freeze-Thaw Conditions.
Service Life Prediction Based on Sorptivity for Highway
Concrete Exposed to Sulfate Attack and Freeze-Thaw
Conditions.
(13985 K)
Bentz, D. P.; Ehlen, M. A.; Ferraris, C. F.; Winpigler,
J. A.
FHWA-RD-01-162; 64 p. March 2002.
Sponsor:
Federal Highway Administration, McLean, VA
Available from:
: National Technical Information Service
(NTIS), Technology Administration, U.S. Department of
Commerce, Springfield, VA 22161.
Telephone:
1-800-553-6847 or 703-605-6000;
Fax: 703-605-6900; Rush
Service (Telephone Orders Only) 800-553-6847;
Website:
http://www.ntis.gov
Keywords:
highways; concretes; weather effects; concrete bridge
decks; concrete pavements; environmental conditions;
freeze-thaw degradation; service life; sorptivity;
sulfate attack
Abstract:
This report documents a study that investigated
permeability as an indicator of the general durability
of hydraulic cement concrete. Since many concrete
deterioration mechanisms depend on the ingress of
moistureand other materials into the concrete, it was
theorized that permeability might be a good indicator of
durability potential. During the project, it was
detennined that sorptivity is the most relevant
transport characteristic of the concrete. A test method
for sorptivity was therefore developed, which has two
different setups, in order to better reproduce the
exposure condition being simulated. User-friendly
software, CONCLIFE, was then developed for estimating
the service life of concrete pavements and bridge decks
exposed to sulfate attack and freeze-thaw deterioration.
CONCLIFE uses three concrete models and user-specified
data on concrete properties and external environmental
conditions to estimate the time at which the concrete
surface spalls beyond a user-specified limit. Ingress of
sulfate ions and water are the primary means of
degradation considered by the software. CONCLIFE uses
the results of the laboratory test described above;
currently in the ASTM standardization process, for
measuring concrete sorptivity. The software produces
graphs of concrete sorptivity, annual precipitation, and
estimated rates of concrete spalling based on the input.
Details of the experimental program conducted in support
of the software development and the underlying technical
bases for the computer models employed in CONCLIFE are
also included.
Building and Fire Research Laboratory
National Institute of Standards and Technology
Gaithersburg, MD 20899