Use of Anhydrite in Building Materials

In this thesis, the binding (hydraulic behavior) of natural anhydrite in building materials and the interaction of natural anhydrite used as a binder with different aggregates were investigated. For this purpose, various physico-mechanical properties of mortar samples formed by adding micronized natural anhydrite (CaSO4, MNA) at varying ratios to crushed sands of different origins were investigated. Natural anhydrite, Portland cement and crushed sand (limestone, dolomitic limestone, silica, granite) were used as raw materials. The prepared mortar mixtures were subjected to tests according to relevant standards of Turkish and The European Union standard TS EN 998-1. In addition, thermal conductivity and ultrasound velocity experiments, microstructure (XRD, FTIR, TG/DTA, SEM) investigations and cost analyses were performed. The predictability of the physico-mechanical properties of mortars with ultrasound velocities was analysed. The results showed that micronised natural anhydrite in the mortar mix can replace cement in certain proportions as a binding material. It was also found that the use of micronised natural anhydrite in mortars has a positive effect on insulation, water absorption, energy input and production cost. This situation indicates that micronised natural anhydrite can replace cement at certain levels in non-bearing building elements such as fine-coarse plaster, repair mortar and filling material; it can be used smoothly and efficiently as an important building material especially in terms of cost effectiveness, environmental sustainability and insulation properties. Key words: Natural anhydrite, crushed sand, mortar, cost, insulation