Rheological behaviour of calcium aluminate cement mortars and investigation of the long term strength-durability properties

In order to propose solutions to the problems arising from the conversion reactions in the hydration process of calcium aluminate cement (CAC) and to stabilize the strength development at the long term, mortars have been prepared by incorporarting by weight to CAC with %8-%16 micro silica, %30-%50 CaSO4 and %20-%50 Portland cement. The flow, consistency, setting time and rheological behavior of these mixtures have been investigated. The development of flexural and compressive strengths of mortars up to 400 days have been determined at two different curing conditions (continuous curing at 20±5oC and after heating at 50±1oC for the first 21 days). The crystal structure, morphology and pore size distribution of the hydration products of the specimens have been analyzed with the support of microstructural studies (XRD, DTA-TGA, SEM-EDS, mercury intrusion porosimetry). As a result, it has been seen that in case of using appropriate additive types in the determined ratios, CAC mortar exhibiting improved properties suitable for the special application areas in terms of fresh state properties can be obtained. It has been determined that, it is possible to obtain stable products in the hydration process of CAC with the use of additives in appropriate proportions and it has been concluded that the mortars obtained with the use of additives in appropriate proportions with CAC show long term strength development without any time-dependent strength loss. In addition, it was determined that the long-term strength of the mortars containing CAC could be stabilized at an early age with the preheat-based curing method applied in this study. With the applied curing processes and the incorporation of mineral additives, solutions have been developed for the drawbacks of CAC. It is also possible to produce mortar with a low carbon footprint by reducing the CAC dosage.