Revised edition - 2005

Chemical agents that can destroy concrete may be found in the ground. In the UK, sulfates and acids naturally occurring in soil and groundwater are the agents most likely to attack concrete. The effects can be serious leading to expansion and softening of concrete. Many other substances are aggressive, most resulting from human activity, but they present less of a problem since they only rarely come into contact with concrete in the ground.

This new edition of BRE Special Digest 1 (SD1:2005) updates and consolidates Parts 1 to 4 of the previous edition published in 2003 (the first edition of SD1 replaced Digest 363). It replaces the 2003 edition and has been revised to reflect new thinking and changes to British Standards. The main changes are:

- a new ranking of cements with respect to sulfate resistance

- removal of the aggregate carbonate range

- revision of sulfate class limits

- simpler requirements for additional protective measures.

SD1:2005 provides practical guidance on the specification of concrete for installation in natural ground and in brownfield locations. The procedures given for ground assessment and concrete specification cover the fairly common occurence of sulfates, sulfides and acids. They also cover the more rarely occurring aggressive carbon dioxide found in some ground and surface waters.

This Special Digest presents the subject in 6 parts:

- Part A introduces the phenomenon of chemical attack of concrete in the ground

- Part B describes modes of chemical attack and discusses the mechanisms of the principal types, including sulfate and acid attack, and the action of aggressive carbon dioxide.

- Part C deals with assessment of the chemical aggressiveness of the ground.

- Part D gives recommendations for the specification of concrete for general cast-in-situ use in the ground.

- Part E gives recommendations for specifying surface carbonated precast concrete for general use in the ground.

- Part F includes design guides for specification of specific precast concrete products, including pipeline systems, box culverts and segmental linings for tunnels and shafts.