ETTRINGITE AND THAUMASITE FORMATION CONDITIONS IN CONCRETE STRUCTURES
| Authors | |
|---|---|
| Year of publication | 2007 |
| Type | Article in Periodical |
| Magazine / Source | Acta Geologica Universitatis Comenianae |
| MU Faculty or unit | |
| Citation | |
| Field | Geology and mineralogy |
| Keywords | Thaumasite;ettringite;concrete; degradation;petrography;aggregate |
| Description | The significance of specific analytical study of cementitious materials (matrix and filling material) becomes very interesting and important during several last years. This study is focused on mineral composition of matrix in concrete, and in particular on petrographic character of aggregates. Aggregates of these samples can be divided into different groups, which mean that aggregates were formed in different geological environments or they were artificially prepared. In several samples was verified that ASR reaction precedes sulphate reaction. Because phthanites (Paleozoic silica rock) and porcelanites were observed in aggregates it had to be verified formation of ASR reaction products. Results were obtained from study of highway concrete, colcrete, expanded-clay concrete and reinforced concrete from a historical bridge structure. In samples of highway and reinforced concrete thaumasite and ettringite were observed, while in lightweight concrete only ettringite occurred. On several occasions the effect of biocorrosion in sulphate formation in concrete could also be proved. |
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