Bridges

Cover of Specifying Sulfate-Resisting Concrete
Specifying Sulfate-Resisting Concrete
  • Publication no: ABC-SAS009-11
  • Published: 31 October 2011

The Sulfate-resisting concrete is traditionally specified by cement type and concrete mix proportions in terms of maximum water-cement ratio and/or minimum cement content.

Cement Concrete & Aggregates Australia (CCAA) has recently completed a major research project on the performance and specification of sulfate-resisting concrete. The research examines the long-term dimensional stability and strength retention of nineteen concrete mixes in 5% sodium sulfate solutions maintained at pH 7 and 3.5.

The concretes were made from 8 cements, six of these were sulfate-resisting cements (Type SR) in accordance with the Australian Standard AS 3972. The concretes were proportioned at watercement ratios of 0.4, 0.5 and 0.65. The coefficient of water permeability and a new rapid sulfate permeability of the concretes were determined at the age of 28 days on 3 days moist-cured cylindrical discs. The rapid sulfate permeability is a 6-hour accelerated test, based on ASTM C1202, and measures the sulfate permeability in term of coulombs. Sulfate-resisting concrete can be produced by specifying the use of a performance-based AS 3972 Type SR cement and a performance-based limit on either a water permeability coefficient of 2.0x10 -12 m/s or a rapid sulfate permeability of 2000 coulombs. These concretes were found to be resistant to both neutral and acidic sulfate conditions.