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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This document Newer versions Older versions. Want access to British Standards? Design guides for specific precast products incorporating March amendment No longer current but cited in Building Regulations guidance.
This is used to create products, tools and standards that drive positive change across the built environment.
In the four years sincemuch of the research recommended by the TEG Report has been completed.
A review of the brw background to sulfate assessment has thrown light on how the current discrepancy came about. 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. 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.
No field data bbre appear to have been available for correlation with sulfate classes based on sulfate levels in groundwater. 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.
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 ber made by carbonates. BRE is a building science centre that generates new knowledge through research. As in the previous cases, the concrete contained carbonate-bearing aggregates.
The Red document status indicator indicates that the document is an old version The document has likely been withdrawn by the publisher, also the meta data presented here may be out of date as it is no longer being maintained by the editorial teams at NBS. In all three cases the concrete contained carbonate-bearing limestone aggregates.
The procedures given for the ground assessment and concrete specification cover the fairly common occurrences of sulfates, xd1 and acids, and the more rarely occurring aggressive carbon dioxide found in some ground and surface waters, which brf concrete foundations and sub-structures.
Key outcomes in respect of the mechanism of TSA and concrete sf1 have been: In the majority of 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 actual occurrence of Ss1. The current and intended new limits for sulfate classes based on 2: SD 1 Concrete in aggressive ground. The new limits bring sulfate classification based on 2: Design guides for common applications incorporating March amendment No longer current but cited in Building Regulations guidance.
Design guides for common applications. Again there may be more recent versions of the document. These ball-park limits were converted in in BRE Digest to 2: In the early s, the thaumasite form of sulfate attack TSA became recognised as a separate mechanism affecting concrete in the UK.
Home Background to revision Key changes in SD1: Assessing the aggressive chemical environment. The Trust uses the profits made by the BRE companies to fund research and education that advances knowledge of the built environment.
In particular, it can come from se1 dissolved in groundwater. 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 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 is unfortunate that, through these changes, they gained an apparent precision that has imparted greater confidence in the derived classification than is warranted. It has long been known in the UK that concretes made with Portland cements are vulnerable to attack by gre in the ground. Design guides for specific precast products. 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 Together with other findings, such as deficiencies in guidance for ground assessment, the new knowledge has prompted the current major revision of SD1.
Background to the revision One of the key drivers ber revision of BRE Digests dealing with concrete in aggressive ground since the s has been a growing recognition of the occurrence the thaumasite brd of sulfate attack TSA in UK buildings and structures.