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Sorption of Water in Mortars and Concrete.

pdf icon 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.


building technology; capillary sorption; concretes; mortar; experimental design; sand


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.