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
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”.
“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.
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
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
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
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.
“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.
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.