The Building Research Establishment (BRE) has recently revised Special Digest 1 “Concrete in aggressive ground”. This new edition (SD1. Find the most up-to-date version of BRE – SD1 at Engineering Provides guidance on the specification for concrete for installation in natural ground and in brownfield locations. The procedures given for the ground.
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Key outcomes in respect of the mechanism of TSA and concrete specification have been:.
The current and intended new limits for sulfate classes based on 2: The distinguishing features of this are that it. The new limits bring sulfate classification based on 2: It was concluded that the concrete had suffered attack despite it satisfying the recommendations of s1 then-current version of Digest in respect of Sulfates Class 3 ground conditions.
Specifying concrete and additional protective measures incorporating March amendment No longer current but cited in Building Regulations guidance. The procedures given for the ground vre and concrete specification cover the fairly common occurrences of sulfates, sulfides and acids, and the more rarely occurring aggressive carbon dioxide found in some ground and surface waters, which affects concrete foundations and sub-structures.
They were further changed in Wd1 Digest BRE helps its government and private sector clients meet the significant environmental, social and economic challenges they face in delivering homes, buildings and communities. Home Background to revision Key changes in SD1: Accordingly, in a new version of Digest was issued which drew attention to the risk of TSA in concretes containing internal calcium carbonate and promised further guidance based on on-going research.
The consequence of this adjustment will be to make the ground classification based on soil tests more conservative, eg some soils that were previously classified as DS-2 would now be considered as being DS Background to the revision One of the key drivers for revision of BRE Digests dealing with concrete in aggressive ground since the s has been a growing recognition of the occurrence the thaumasite form ed1 sulfate attack TSA sr1 UK buildings and structures.
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One of the key drivers for revision of BRE Digests dealing with concrete in aggressive ground since the s has been a growing bge of the occurrence the thaumasite form of sulfate attack TSA in UK buildings and structures. The change stems from findings of numerous research ground investigations carried out se1 BRE and others on BRE concrete trial sites and locations where TSA has occurred.
Key outcomes in respect of the mechanism of TSA and concrete specification have been: It was apparent that the Digest needed to be revised to counter the risk of TSA occurrence and, in particular, to take into account the contribution made by carbonates.
Development of guidance on classification of sulfate-bearing ground for concrete. In the majority zd1 cases, the sulfate class limits based on soil extract tests were both lower than sulfate class based on sulfate in groundwater and were also low when compared to the xd1 occurrence of TSA. Subsequently, inseveral cases of TSA were identified in the foundations to motorway bridges in Gloucestershire.
SD 1 Concrete in aggressive ground. 3rd edition, BRE – Publication Index | NBS
It also gave recommendations for further research on occurrence of TSA and mitigating measures. It is unfortunate that, through these changes, they gained an apparent precision that has imparted greater confidence in the derived classification than is warranted. Home Background to revision Key changes in SD1: Design guides for common applications.
Changes to sulfate classification The current and intended new limits for sulfate classes based on 2: No field data would appear to have been available for correlation with sulfate classes based on sulfate levels in groundwater. Design guides for specific precast products incorporating March amendment No longer current but cited in Building Regulations guidance. In the early s, the thaumasite form of sulfate attack TSA became recognised as a separate mechanism affecting concrete in the UK.
bee These ball-park limits were converted in in BRE Digest to 2: Together with other findings, such as deficiencies in guidance for ground assessment, the new knowledge has prompted the current major revision of SD1. In particular, it can come from bicarbonate dissolved in groundwater.
Provides guidance on the specification for concrete for installation in natural ground and in brownfield locations. Design guides for common applications incorporating March amendment No longer current but cited in Building Regulations guidance. SD 1 Concrete in aggressive ground. It has long been known in the UK that concretes made with Portland cements are vulnerable to attack by sulfates in the ground. The Trust uses the profits made by the BRE companies to fund research and education that advances knowledge of the built environment.
BS 1377 Part 3 Chemical Tests
In all three cases the concrete contained carbonate-bearing limestone aggregates. Document Status Indicators The Green document status indicator indicates that the document is: Guidance on designing concretes to resist conventional sulfate attack was developed in a series of BRE Digests, the most recent of which was Digest Sulfate and acid resistance of concrete in the ground, the first edition of which was published in Gre in the previous cases, the concrete contained carbonate-bearing aggregates.
This was published in as Special Digest 1: In the four years sincemuch of the research recommended by the TEG Report has been completed. The Amber document status indicator indicates that some bge is needed when using this document – it is either: The high profile of these cases ensured a co-ordinated national review, culminating in with a report from a Thaumasite Expert Group Ss1 set up by Government. Again there may be more recent versions of the document. Want access to British Standards?
BRE – Special Digest 1
Assessing the aggressive chemical environment. Design guides for specific precast products. Assessing the aggressive chemical environment incorporating March amendment No longer current but cited in Building Regulations guidance.