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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The distinguishing features of this are that it. These ball-park limits were converted in in BRE Digest to 2: Again there may be more recent versions of the document.
BRE – Special Digest 1
The Trust uses the profits made by the BRE companies to fund research and education that advances knowledge of the built environment. Design guides for specific precast products incorporating March amendment No longer current but cited in Building Regulations guidance. Together with other findings, such as deficiencies in guidance brd ground assessment, the new knowledge has prompted the current major revision se1 SD1.
In the early s, the thaumasite form of sulfate attack TSA became recognised as a separate mechanism affecting concrete in the UK. It also gave recommendations for further research on occurrence of TSA and mitigating measures.
Design guides for specific precast products. This is used to create products, tools and standards that drive positive change across the built environment. Changes to sulfate classification The current and intended new limits for sulfate classes based on 2: BRE is a building science centre that generates new knowledge through research.
BS 1377 Part 3 Chemical Tests
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 This was published in as Special Digest 1: The procedures given for the ground assessment 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.
Assessing the aggressive chemical environment. 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. In particular, it can come from bicarbonate dissolved in groundwater.
The high profile of these cases ensured a co-ordinated national review, culminating in with a report from a Thaumasite Expert Group TEG set up by Government. Want access to British Standards? Key outcomes in respect of the mechanism of TSA and concrete specification have been:.
No field data would appear to have been available for correlation with sulfate classes based on sulfate levels in groundwater. 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 of sulfate attack TSA in UK buildings and structures. In all three cases the concrete contained carbonate-bearing limestone aggregates. It was concluded that the concrete had suffered attack despite it satisfying the recommendations of the then-current version of Digest in respect of Sulfates Class 3 ground conditions.
Document Status Indicators The Green document status indicator indicates that the document is: The Amber document status indicator indicates that some caution is needed when using this document – it is either: As in the previous cases, the concrete contained carbonate-bearing aggregates.
Development of guidance on classification of sulfate-bearing ground for concrete. They were further changed in BRE Digest The Red document status indicator indicates that the document is an old version The document has likely been withdrawn by the publisher, also the meta data presented here may be out of date as it is no longer being maintained by the editorial teams at NBS. Provides guidance on the specification for concrete for installation in natural ground and in brownfield locations.
Specifying concrete and additional protective measures incorporating March amendment No longer current but cited in Building Regulations guidance. SD 1 Concrete in aggressive ground.
The change stems from findings of numerous research ground investigations carried out by BRE and others on BRE concrete trial sites and locations where TSA has occurred. In the four years sincemuch of the research recommended by the TEG Report has been completed.
It has long been known in the UK that concretes made with Portland cements are vulnerable to attack by sulfates in the ground. Accordingly, in a new version of Digest was sd which drew attention to the risk of TSA in concretes containing internal calcium carbonate and promised further guidance based on on-going research.
BRE helps its government and private sector clients meet the significant environmental, social and economic challenges they face in delivering homes, buildings and communities. This document Newer versions Older versions. Background to the revision One of the key drivers for revision of BRE Digests dealing bree concrete in aggressive ground since the s has been a growing recognition of the occurrence the thaumasite form of sulfate attack TSA in UK buildings and structures.
It is unfortunate that, through these changes, they gained an apparent precision that has imparted greater confidence in the derived classification than is warranted.
Gives procedures for specification of concrete and applies to both buildings and civil engineering construction. A review of the zd1 background to sulfate assessment has thrown gre on how the current discrepancy came about. Subsequently, inseveral cases of TSA were identified in the foundations to motorway bridges in Gloucestershire.