Title: Durability Predictions From Rate of Diffusion Testing of Normal Portland Cement, Fly Ash, and Sag Concrete

Author(s): K.E. Philipose, R. F. Feldman, and J. J. Beaudoin

Publication: Symposium Paper

Volume: 126

Issue:

Appears on pages(s): 335-354

Keywords: diffusion; durability; fly ash; ionic ingress; portland cements; slag cements; waste treatment; Materials Research

DOI: 10.14359/2200

Date: 8/1/1991

Abstract:
A waste repository for the underground disposal of low-level radioactive waste, called IRUS (Intrusion Resistant Underground Structure), is planned at the Chalk River Nuclear Laboratories. It relies greatly on the durability of concrete for a minimum of 500 years of service life. A research program based on laboratory testing to design a durable concrete and predict its useful engineered service life is in progress. The durability of concrete depends on its resistance to deterioration from both internal and external causes. Since the rate of degradation depends to a major extent on the rate of ingress of aggressive ions into concrete, laboratory testing is in progress to establish the diffusion rates of chlorides and sulfate ions. A total of 1000 concrete specimens and 500 paste specimens are being exposed at 22 and 45 C to 25 different combinations of corrosive agents, including Co2. Procedures to measure the ionic penetration profile and to determine the factors controlling diffusion of ions in the various concretes have been developed. The paper presents initial results from the research program and the longevity predictions to qualify concretes for the IRUS waste repository, based on 16 months of diffusion testing on laboratory specimens.