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Pulverised Fuel Ash and Preventing the Thaumasite Form of Sulfate Attack
| Content Provider | Semantic Scholar |
|---|---|
| Author | Sear, Lindon K. A. |
| Copyright Year | 2006 |
| Abstract | Since its formation the UKQAA has been involved with numerous research projects looking at the thaumasite form of sulfate attack. These have investigated the effects of aggregate type, cement type, proportions of secondary materials such as pulverised fuel ash (PFA), oxidation conditions of pryritic clay, etc. The majority of this work has been carried out at 5C, the optimum temperature at which this deleterious reaction between sulfate and the cement hydration products occurs. The laboratory investigations at such low temperatures disadvantage pozzolanas such as PFA because of the sensitivity of the pozzolanic reaction to changes in temperature. Although laboratory findings are not reflected in concrete in real situations, they have resulted in a very conservative approach in specifications with regard to the use of PFA in situations where thaumasite may be a problem. In order to address this issue, the UKQAA funded a three year laboratory programme commencing in August 2004 to investigate the effects of using an annual cyclic temperature profile as would be found 1m down into the soil. This was designed to replicate the true risks of thaumasite attack on concretes containing different proportions of ash. This paper will review the findings of the various projects carried out on the thaumasite form of sulfate attack and the one year results of the laboratory programme using temperature cycling. |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://www.ukqaa.org.uk/wp-content/uploads/2014/02/AshTech-2006-Sear.pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
