Investigation of compatibility of calcium aluminate cement with plasticizing chemical admixtures from the view point of consistency retainig performance

Calcium aluminate cement has superior properties such as fast strength gain, abrasion resistance, resistance to high temperatures and chemical, biological and acid resistance compared to ordinary Portland cement. One of the most important reasons why it is not widely used is its conversion reactions. However, as mentioned in the literature, the harmful effects of conversion reactions are highly prevented with water/cement ratios below 0.4. Nevertheless, utilisation of low water/cement ratios results in both consistency and consistency retaining problems. In order to avoid these problems, calcium aluminate cement should be used with superplasticizer admixtures. In this study, the effects of different polycarboxylate based superplasticizer admixtures on the consistency and consistency retention performance of calcium aluminate cement were investigated. In this context, firstly, consistency test was applied to cement paste with and without admixtures. The flow protocol applied to the cement paste which is suitable for working in rheometer, depending on the time, immediately after mixing the cement with water and then at the end of 30 minutes, 60 minutes and 90 minutes. As a result of the experiments, it was revealed that a workable consistency was obtained by using polycarboxylate based superplasticizer admixtures at water/cement ratios which were too dry to be able to work in the rheometer without admixtures and this consistency was maintained for a long time.