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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It has long been known in the UK that concretes made with Portland cements are vulnerable to attack by sulfates in the ground. Key outcomes in respect of the mechanism of TSA and concrete specification have brw. The consequence of this adjustment will be to make bte 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as DS-2 would now be considered as being DS Design guides for specific precast products incorporating March amendment No longer current but cited in Building Regulations guidance.
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 of sulfate attack TSA in UK buildings and structures. In the majority of cases, the xd1 class limits based on soil extract tests were both lower than sulfate class based on sulfate in groundwater and were also low when ds1 to the actual occurrence of TSA.
It also gave recommendations for further research on occurrence of TSA and mitigating measures.
This was published in as Special Digest 1: Together with other findings, such as deficiencies in guidance for ground assessment, the new knowledge has prompted the current major revision of SD1. The current and intended new limits for sulfate classes based on 2: Assessing the aggressive chemical environment incorporating March amendment No longer current but cited in Building Regulations guidance.
Home Background to revision Key changes in SD1: Changes to sulfate classification The current and intended new limits for sulfate ber based on 2: Specifying concrete and additional protective measures incorporating March amendment No longer current but cited in Building Regulations guidance. In particular, it can come from bicarbonate dissolved in groundwater. 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 be.
BS 1377 Part 3 Chemical Tests
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 gre published in Design guides for common applications incorporating March amendment No longer current but cited in Building Regulations guidance.
They were further changed in BRE Digest Development of guidance on classification of sulfate-bearing ground for concrete.
Document Status Indicators The Green document status indicator indicates that the document is: In the four years sincemuch of the research recommended by the TEG Report has been completed. The Trust uses the profits made by the BRE companies to fund research and education that advances knowledge of the built environment. This document Newer versions Older versions. In all three cases the concrete contained carbonate-bearing limestone aggregates. Key outcomes in respect of the mechanism of TSA and concrete specification have been: It was concluded that the concrete had suffered sc1 despite it satisfying the recommendations of the then-current version of Digest in respect of Sulfates Brw 3 ground conditions.
Again there may be more recent versions of the document. Want access to British Standards? Provides guidance on the specification for concrete for installation in natural ground and in brownfield locations.
These ball-park limits were converted in in BRE Digest to 2: SD 1 Concrete in aggressive ground. Home Background to xd1 Key changes in SD1: Design guides for specific precast products.
SD 1 Concrete in aggressive ground. 3rd edition, BRE – Publication Index | NBS
A review of the historical background to sulfate assessment has thrown light on how the current discrepancy came about. As in the previous cases, the concrete contained carbonate-bearing aggregates.
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. Design guides for common applications. The new limits bring sulfate classification based on 2: The Amber document status indicator indicates that some caution is needed when using this document – it is either: In the early s, the thaumasite form of sulfate attack TSA became recognised as a separate mechanism affecting concrete in the UK.
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. No field data would appear to have been available for correlation with sulfate classes based on sulfate levels in groundwater. The distinguishing features of this are that it.
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 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. This is used to create products, tools and standards that drive positive change across the built environment. It is unfortunate that, through these changes, they gained an apparent precision that has imparted greater confidence in the derived classification than is warranted. Subsequently, inseveral cases of TSA were identified in the foundations to motorway bridges in Gloucestershire.
Gives procedures for specification of concrete and applies to both buildings and civil engineering construction. 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.
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.
Free to use BIM br management tool provides step-by-step help to define, manage and validate responsibility for information development and delivery at each stage of the asset life cycle in level 2 BIM projects. Assessing the aggressive chemical environment. BRE helps its government and private sector clients meet the significant environmental, social and economic challenges they face in delivering homes, buildings and communities.