Carbonation process and properties of a new lime mortar with added sepiolite

[EN]Sepiolite is a clay mineral (Si12Mg8O30(OH)4(OH2)4) which due to its fibrous structure has considerable absorbent and adsorbent properties making of it an ideal material for supporting different products, such as toxines, oil, biocides, etc. In this work, the influence of the sepiolite on the carbonation process of lime mortars with sand/lime3/1 ratio, and also on the physical, chemical, mechanical and rheological properties as well as the microstructural characteristics of the same mortars has been studied. It has been proved that sepiolite slows down the rate of carbonation process in these lime mortars due to its capacity for water adsorption without affecting the mechanical behaviour of the mortars. However, it has been observed that sepiolite affects the microstructural development of the composite. The influence of the sepiolite on the rheological behaviour of these lime mortars has also been established by a mathematical equation which correlates the viscosity and the content of sepiolite in the mortar. This equation can also determine, for different water/(lime + sand) ratios, the optimum amount of sepiolite which could be added to the mortar for achieving the best plasticity.