Substituting Natural Pozzolan with Artificial Derived from Industrial Perlite Waste for Mortar Production

Pozzolans were used selectively in combination with lime to produce mortars used in structures where watertightness was required such as aqueducts, baths and pipes many centuries ago. The appreciated properties of mortars containing pozzolans were the increased durability and strength and the dense structure in relation to pure lime mortars. Ancient engineers managed to produce composites which proved their durability and their study provides significant information to modern materials technology. Today, natural pozzolans are used as binders for the production of mortars in order to produce repair materials compatible to old authentic mortars and also in cement industry. Thus, the reserves of natural pozzolans are not sufficient for the explosive development of the construction sector. Additional sources of pozzolanic materials were sought, such as industrial by-products used as supplementary materials. In the case of their use, the purpose is not only the safe and massive disposal of large quantities of materials that would otherwise burden the environment, but also the utilization of their special characteristics to produce different types of composites. Recent studies have documented that waste perlite, may present induced pozzolanic reactivity and could be used as an alternative pozzolanic material. Additionally, the substitution of natural pozzolan with waste perlite in lime-based mortars and grouts, has proved to be beneficial for their overall performance.