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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BS 1377 Part 3 Chemical Tests
The distinguishing features of this are that it. Want access to British Standards? 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.
Free to use BIM project 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. In all three cases the concrete contained carbonate-bearing limestone aggregates.
Design guides for common applications incorporating March amendment No longer current but cited in Building Regulations guidance. The current and intended new limits for sulfate classes based on 2: In particular, it can come from bicarbonate dissolved in groundwater. Home Background to revision Key changes in SD1: No field data would appear to have been available for correlation with sulfate classes based on sulfate levels in groundwater.
Together with other findings, such as deficiencies in guidance for ground assessment, the new knowledge has prompted the current major revision of SD1. 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.
Design guides for common applications. Document Status Indicators The Green document status indicator indicates that the document is: 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.
Specifying concrete and additional protective measures incorporating March amendment No longer current but cited in Building Regulations guidance. Again there may be more recent versions of the document. SD 1 Concrete in aggressive ground. 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.
The new limits bring sulfate classification based on gre Background to the revision One of the key drivers for revision of BRE Digests dealing with sd 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. As in the previous cases, the concrete contained carbonate-bearing aggregates.
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.
Design guides for specific precast products. 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 It is unfortunate that, through these changes, they gained an apparent precision that has imparted br confidence in the derived classification than is warranted.
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. In the majority of cases, the sulfate class limits based on soil extract tests were both lower than sulfate class sd11 on sulfate in groundwater and were also low when compared to the actual occurrence of TSA. This is used to create products, tools and standards that drive positive change across the built environment.
It has long been known in the UK that concretes made with Portland cements are vulnerable to attack by sulfates in the ground. Provides guidance on the specification for concrete for installation in natural ground and in brownfield locations. Development of guidance on classification of sulfate-bearing ground for concrete. Key outcomes in respect of the mechanism of TSA and concrete specification have been:.
A review of the historical background to sulfate assessment has thrown light on how the current discrepancy came about.
SD 1 Concrete in aggressive ground. 3rd edition, BRE – Publication Index | NBS
Changes to sulfate classification The current and intended new limits for sulfate classes based on 2: Key outcomes in respect of the mechanism of TSA and concrete specification have been: The Trust uses the profits made by the BRE companies to fund research and education that advances knowledge of the built environment. They were further changed in BRE Digest In the four years sincemuch of the research recommended by the TEG Report has been completed.
Subsequently, inseveral cases of TSA were identified in the foundations to motorway bridges in Gloucestershire. BRE helps its government and private sector clients meet the significant environmental, social and economic challenges they face in delivering homes, buildings and communities. 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.
The Amber document status indicator indicates that some caution is needed when using this document – it is either: Gives procedures for specification of concrete and applies to both buildings and civil engineering construction. BRE is a building science centre that generates new knowledge through research. Home Background to revision Key changes in SD1: 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 Assessing the aggressive chemical environment.
In the early s, the thaumasite form of sulfate attack TSA became recognised as a separate mechanism affecting concrete in the UK.
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. It also gave recommendations for further research on occurrence of TSA and mitigating measures. Assessing the aggressive chemical environment incorporating March amendment No longer current but cited in Building Regulations guidance. This was published in as Special Digest 1: These ball-park limits were converted in in BRE Digest to 2: This document Newer versions Older versions.
Design guides for specific precast products incorporating March amendment No longer current but cited in Building Regulations guidance.