Discontinuous capillary porosity in concrete – Does it exist?

Title: Discontinuous capillary porosity in concrete – Does it exist?
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: 26
Language: English

Abstract: Codes and standards set limits on the maximum water to cementitious ratio and other mixture design parameters for concrete exposed to deleterious environments. The aim of these codes and standards is to maximize the service life of concrete structures. Given that the capillary pore system presents the pathway for the ingress of deleterious substances, it follows that the formation of a discontinuous capillary pore system is highly desirable. While T. C. Powers and his colleagues showed this in the 1940’s, there has been little work done since then with modern cementing materials. The time required to achieve discontinuity was based on the degree of hydration of cement under standard laboratory conditions. Since that time, changes in the chemistry of cement and its particle size distribution as well as the use of supplementary cementing materials and chemical admixtures have changed the nature of concrete. Saturated water permeability, as well as other transport properties, was measured for a range of concretes at 28 days of age. In addition, capillary porosity of mortar and paste were measured at the same ages. These properties were used to determine if capillary discontinuity follows the relationship put forward by Powers or if it exists at all due to “interfacial transition zone” effects.

Online publication: 2004-03-25
Classification: Measuring W/C and Porosity
Publication type : full_text
Public price (Euros): 0.00
doi: 10.1617/2912143926.013