Effect of drying history on the course of cement hydration

Title: Effect of drying history on the course of cement hydration
Author(s): Th. Adam, P. Grübl
Paper category : conference
Book title: International RILEM Symposium on Concrete Science and Engineering: A Tribute to Arnon Bentur
Editor(s): J. Weiss, K. Kovler, J. Marchand, and S. Mindess
Print-ISBN: None
e-ISBN: 2912143926
Publisher: RILEM Publications SARL
Publication year: 2004
Nb references: 8
Language: English

Abstract: Cement hydration is a time-dependent reaction between cement and water. It stops, if not enough water is available for a further reaction. Before it breaks off, the hydration kinetics retards depending on the internal moisture content. In this connection, two characteristic values can be defined. The “upper” limiting moisture content specified the amount of evaporable water, which must be at least in the concrete that the hydration occurs without restrictions. This value is mainly influenced by the initial water-cement ratio. The “lower” limiting moisture content specified the minimum evaporable water content which is necessary that hydration starts at all. It is corresponding with the compensatory moisture content at 95 % relative humidity. The time needed for the moisture to fall below the two limiting values depends strongly on the rate of evaporation. For specimens under otherwise equal conditions the evaporation is specified by the gradient of the humidity near to the surface and the surrounding atmosphere. The evaporation rate increases if the relative humidity of the surrounding atmosphere is dropping. This paper discloses that the course of hydration is a function of the internal moisture. The correlation between the curing duration, relative humidity, type of cement and water-cement ratio on the evaporation is proven and quantitatively determined. Basic approaches of a mathematically model were developed. On the basis of these results, predictions about the necessary curing duration can be made.

Online publication: 2004-03-25
Classification: Pore Structure and Curing
Publication type : full_text
Public price (Euros): 0.00
doi: 10.1617/2912143926.010