Heat-Acid-Resistant Light Concretes on the Base of Volcanic Tuff Lava and Pumice Aggregates of Armenia

Abstract

The territory of Armenia is characterized by a wide variety of volcanic natural porous rocks with extremely rich natural resources. Tuff stone is one the varieties and is traditionally used as a masonry material, and waste, estimated at millions of cubic meters has accumulated near the mining areas and it’s disposal is an important environmental issue. Slag and pumice stones, as well as some types of tuffs, are used as aggregates for general-construction lightweight concretes, and as heat insulating backfills, etc. Since the 1980s, we have begun systematized scientific studies to identify the natural potential and the most optimal branches for the use of these rocks, where it is possible to obtain the maximum technical and economic benefits through the targeted use of their specific natural properties. Taking into account the conditions of these rock formation, as well as the high prices available on the world market and the demand for lightweight, heat-resistant insulating concrete, first of all, by complex, versatile studies, they are classified by high-temperature properties, technical capabilities and specificity of using some varieties as aggregates for lightweight heat-resistant concrete, with application temperature up to 800...1100°C. It is shown that, compared with the expensive artificial porous heat-resistant aggregates widely used in practice, these rocks are out of concurrence, as the corresponding compositions, porosity of the structure and high-temperature processing were obtained in natural conditions, due to which they do not require manufacturing costs for particular components and high-temperature processing and in the natural form are ready to be used in this area. Along with this, some of them also have high acid resistance and are suitable for use in the most valuable concretes with the simultaneous triple effect of lightness, heat resistance and acid resistance.