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THE THAUMASITE FORM OF SULFATE ATTACK Thaumasite form of sulfate attack
| Content Provider | Semantic Scholar |
|---|---|
| Author | Halliwell, Mary A. G. |
| Copyright Year | 1999 |
| Abstract | Recent site and laboratory investigations carried out by BRE on problems of sulfate attack have shown that the mineral thaumasite has been responsible for the deterioration of concretes and mortars specifically designed to give good sulfate resistance. It has been shown that thaumasite may form if concretes containing commonly used limestone aggregates are exposed to sulfate solutions. Therefore, among other measures there is a need to establish a type of carbonate aggregate concrete which can resist this form of sulfate attack. Previous work carried out by BRE indicated that the use of blastfurnace slag cement could improve the resistance of carbonate aggregate concretes. In order to examine this possibility further sulfate resistance tests have been carried out at 5°C and 20°C on concretes containing various limestone aggregates. The main cementitious materials used with these aggregates were ordinary Portland cement (OPC), sulfate resisting Portland cement (SRPC), and an ordinary Portland cement blended with ground granulated blastfurnace slag (OPC/ggbs). This paper describes the one and two year results for these sulfate resistance tests. The results found that the ggbs performed satisfactorily with the good quality limestone aggregates; the concrete containing ggbs/Carboniferous limestone performed extremely well under the most aggressive conditions, and under the same aggressive conditions, the ggbs concretes did not perform satisfactorily when combined with the lower grade limestone aggregates. The SRPC concretes, stored in medium to strong magnesium sulfate solutions at 5°C, performed satisfactorily at 1 year with all grades of aggregate. However after two years, they have started to show unsatisfactory sulfate resistance with the magnesian limestone and lower grade calcareous limestone aggregate. This delay in deterioration of SRPC concretes has been seen in other sulfate resistance test work at BRE. The ggbs concretes containing good quality limestone aggregate continued to perform better than the equivalent OPC concretes. |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://www.irbnet.de/daten/iconda/CIB1964.pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
