Technical Note: What is total potential sulfate?

Definition and Background

Total Potential Sulfate (TPS) represents the chemical equivalent of the maximum sulfate that could be theoretically generated if all sulfur within a sample of a geological material (e.g., soil, rock, aggregate etc.) was to oxidise.

TPS is determined as part of the assessment of sulfur-species, in combination with determination of water-soluble sulfate, acid-soluble sulfate and total sulfur. This conversion has been used since at least the late 1970s (e.g., Nixon 1978, Wilson 1987) and is now found in most UK guidance, having been formalised in BR 279 (Bowley 1995) and used in the M5 motorway thaumasite investigations (TEG 1999).… Read the rest

Research Paper: Derived chemical terms for sulfur-species assessment

derived chemical terms

Tom St John (University of Bristol) has published a paper on the use and limitations of derived chemical terms for assessing sulfur-species in ground materials. The author considers a wide range of derived chemical terms used in the literature, such as equivalent pyrite and total potential sulfate and the limitations involved in their application.

The paper is titled “Use of derived terms for sulfur-species in geological materials”.

Abstract

“An assessment of the sulfur/sulfide content of ground materials for civil engineering purposes is essential in order to understand the potential for sulfate development. In the absence of detailed petrographic/mineralogical data, terms such as “total potential sulfate”, “oxidisable sulfides” and “equivalent pyrite” are often derived from sample test results for total sulfur, water-soluble sulfate and acid-soluble sulfate.
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Research Paper: Sulfur-species in glacial tills

sulfur-species in glacial tills

Brian Hawkins (HM Geotechnics) and Tom St John (University of Bristol) have published a paper on the presence of sulfur-species in glacial tills (boulder clays) and the implications for engineering and construction. The authors consider a case study of road construction (A10) in an area underlain by glacial till in Hertfordshire, UK.

The paper, titled “Engineering significance of sulfur/sulfate in glacial tills” follows prior discussion of the A10 case study by Hawkins (2013):

Hawkins, A.B. (2013). Some engineering geological effects of drought: examples from the UK. Bulletin of Engineering Geology and the Environment.… Read the rest

Research Paper: Use of a granular interface in construction over pyritic ground

Use of a granular interface over pyritic ground

Czerewko and Cross (AECOM) have published a paper on the use of a granular construction interface to separate road pavements from underlying pyritic subgrade. The authors consider case studies and the implications for road construction where such an interface has and has not been used.

The paper, titled “Benefits of a granular construction interface in highway construction over pyritic subgrades for mitigating against deleterious ground effects” follows a prior case history publication by M. Czerewko on the construction of the A46, whereby pyritic subgrade extended over much of the road scheme:

Czerewko, M.A., Cross, S.A., Dimelow, P.G., and Saadvandi, A.… Read the rest

Research Paper: Identification of pyrite induced heave

Pyrite Induced Heave

Taylor, Cripps and Clarke (University of Sheffield) have published a paper on the identification of pyrite induced heave using chemical and structural assessments. The authors consider the use of chemical and structural assessments to determine whether pyritic heave caused structural damage in a number of case studies.

The paper, titled “The identification of pyrite induced foundation heave by chemical and structural assessments” follows prior research on the in-situ investigation of pyritic fill by the authors:

Taylor, A.J., Cripps, J.C., and Clarke, S.D. (2015). The effect of temperature and moisture content on the behaviour of pyritic fill: development of an in situ monitoring system.… Read the rest

Research Paper: Investigation of pyrite heave in Dublin, Ireland

Pyrite Heave in Dublin

Mourice Czerewko (AECOM) and John Cripps (University of Sheffield) have published a paper on the investigation of pyrite heave affecting properties in Dublin, Ireland. The authors report on a case study from north Dublin, where pyrite bearing fill had been used below the new-build property floor slabs.

The paper, titled “Investigation of destructive ground heave affecting new-build properties constructed using pyrite bearing fill in the Dublin area of Ireland” follows prior research on the Irish pyrite problems (click here to view literature on the Irish pyrite issues).

Abstract

“Although structural damage caused by the expansion of bedrock and fills due to the presence of pyrite has been documented internationally since the 1960s, there is an apparent lack of awareness of the potential for these problems in the construction industry, particularly the domestic housing sector.
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Ireland: Second Update on Pyrite Resolution Board Statistics

Pyrite Resolution Board STATISTICS

The Pyrite Resolution Board (PRB) has produced six reports since the Pyrite Remediation Scheme was introduced in February 2014. Further statistics are provided on the PRB website and in recent news articles. See statistics below and follow links for original data.

Pyrite Resolution Board Statistics reported in the sixth quarterly report of the PRB:

26th February 2014 to 3th June 2015:

  • 763 completed applications
  • 33 developments containing multiple applications
  • 49 single site applications
  • 637 Validated applications
  • 520 applications included in scheme
  • Pilot project of 5 dwellings remediated (September to November 2014)
  • 16 dwellings completed remediation in 2015
  • Works contractors in place for 132 dwellings
  • Tendering underway for 65 dwellings
  • Remedial Works Plans under preparation for 163 dwellings
  • Anticipated 236 dwellings to be remediated in 2015
  • 11 dwellings refused from scheme (five have appealed)
  • In 5 cases, agreement has reached with builders/developers regarding contribution towards cost of remediation of 67 dwellings

Pyrite Resolution Board Statistics reported by the Pyrite Resolution Board for 7th June 2015:

  • Total 763 applications (significant pyritic damage)
  • 115 applications in Validation Stage
  • 117 applications at Verification Stage
  • 520 applications included in the scheme
  • 8 applications refused

Pyrite Resolution Board Statistics reported by the Pyrite Resolution Board for 1st May 2015:

  • Total 712 applications (significant pyritic damage)
  • 107 applications in Validation Stage
  • 97 applications at Verification Stage
  • 508 applications included in the scheme
  • 7 applications refused

Pyrite Resolution Board Statistics reported in the fifth quarterly report of the PRB:

26th February 2014 to 31st March 2015:

  • 697 completed applications
  • 33 developments containing multiple applications
  • 49 single site applications
  • 583 Validated applications
  • 496 applications included in scheme
  • Pilot project of 5 dwellings remediated (September to November 2014)
  • Remediation of 20 dwellings commenced in February 2015
  • Contractors appointed to 72 dwellings in March 2015
  • Testing underway for 63 dwellings
  • Remedial Works Plans under preparation for 179 dwellings
  • 11 dwellings refused from scheme (three have appealed)

Pyrite Resolution Board Statistics reported in the fourth quarterly report of the PRB:

26th February 2014 to 1st January 2015:

  • 622 completed applications
  • 27 developments containing multiple applications
  • 47 single site applications
  • 483 Validated applications
  • 321 applications included in scheme
  • Average 3 applications per week since 3rd quarterly report
  • 2 appeals in process
  • Pilot project of 5 dwellings remediated (September to November 2014)

The Irish Independent reported an update on the Pyrite Remediation Scheme statistics for the end of January 2015:

  • Total 632 applications
  • 485 applications Validated
  • 328 applications included in scheme
  • Work at tender stage for 73 dwellings
  • Work completed on 5 dwellings

Pyrite Resolution Board Statistics reported by the Pyrite Resolution Board for 31st October 2014:

  • Total 590 applications
  • 151 applications in Validation Stage
  • 231 applications at Verification Stage
  • 208 applications included in the scheme

Pyrite Resolution Board Statistics reported by the Pyrite Resolution Board for 7th October 2014:

  • Total 575 completed applications and 36 commenced applications
  • 144 applications in Validation Stage
  • 220 applications in Verification Stage
  • 2 Verified applications awaiting decision
  • 206 applications included in the scheme
  • Remediation contracts in place for 5 dwellings
  • 3 applications not considered

Pyrite Resolution Board Statistics reported by the Pyrite Resolution Board for 4th July 2014:

  • Total 521 completed applications and 35 commenced applications
  • 312 applications in Validation Stage
  • 127 applications in Verification Stage
  • 27 Verified applications awaiting decision
  • 52 applications included in the scheme
  • 3 applications not considered
Pyrite Resolution Board Statistics reported by the Pyrite Resolution Board for 15th April 2014:
  • 418 completed applications and 146 commenced applications
  • 84 applications Validated and referred to Verification Stage
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