Sorption of Water in Mortars and Concrete.
Sorption of Water in Mortars and Concrete.
(642 K)
Martys, N. S.; Ferraris, C. F.
Materials for the New Millennium. Proceedings.
Materials Engineering Conference, 4th. Volume 2.
American Society of Civil Engineers (ASCE). November
10-14, 1996, Washington, DC, American Society of Civil
Engineers, New York, NY, Chong, K. P., Editor(s),
1129-1138 pp, 1996.
Keywords:
building technology; capillary sorption; concretes;
mortar; experimental design; sand
Abstract:
Results are presented of a study on the capillary
transport of water in concretes and mortars as a
function of water/cement ratio, sand, size distribution
and curing. Our studies indicate that the sorption of
water with respect to time in concrete exhibits complex
scaling behavior. At early times, of the order of one
hour, the t1/2 scaling of typical sorption theories is
observed. At longer times, of the order of tens of
days, a slow crossover regime is seen as the t1/2
scaling breaks down. At very long times, of order
hundreds of days, a slower uptake which may be driven by
the capillary forces in the smaller gel pores is found.
Again t1/2 scaling is observed but with a much smaller
sorption rate. We describe an empirical fitting form
for data in the different scaling regimes. Aspects of
the experimental design inlcuding sample drying and
exposure to air are discussed. Service life predictions
from such measurements are discussed.
Building and Fire Research Laboratory
National Institute of Standards and Technology
Gaithersburg, MD 20899