| Abstract [eng] |
Rankinite (Ca3Si2O7) is a low-base calcium silicate that can be used as an alternative binder. Its CaO / SiO2 molar ratio is almost twice smaller than Portland cement. Fuel and energy consumption are also lower, as rankinite is obtained at a temperature of ~200 °C lower than cement clinker. Upon combustion of the precursor, rankinite, which will be synthesized under hydrothermal conditions, is expected to further reduce its formation temperature to 1100–1250 °C. Existing production technological lines are suitable and could be used without any significant changes. Because calcium silicates can be synthesized from a variety of materials, it is most cost-effective to use native materials. There are enough raw materials containing both limestone and SiO2 in Lithuania. Rankinite is hydraulically inactive and hardens only in a CO2 environment. A highly durable microstructure of calcium carbonate and silica gel is formed. Since carbonation is determined by diffusion processes, the hardening process depends on many parameters: CO2 pressure, retention time, moisture content, concrete preparation characteristics and etc. It is important to examine them all and reconcile them. |
