Development of Eco-Friendly and Self-Cleaning Lime-Pozzolan Plasters for Bio-Construction and Cultural Heritage

Abstract

Nowadays, the design and use of multi-functional mortars has increased significantly, with interesting applications in the green building and cultural heritage conservation sectors. A key point for a correct adoption of these innovative materials is their behavior along time and their resistance to the weathering. The objective of this project was to define the performance and durability of innovative mortars, in order to use them correctly and to avoid irreparable damage over time. For the development of this project, lime–metakaolin and hydraulic lime–metakaolin based mortars (hereinafter called A, B), as well as A and B with the addition of nano-TiO2 and perlite (hereinafter referred to as A+, B+), have been tested. The focus of the work was to carry out preliminary tests to evaluate the performance and durability characteristics of these mortars, verifying their behavior over time through exposure to artificial aging cycles, including thermal shock cycles in saline solution aerosols, freeze cycles in vapor aerosol, and aging by heat treatment at high temperatures. Before and after each artificial aging cycle, weight measurements, and macroscopic and microscopic observations were performed in order to evaluate possible structural changes. The characteristics of the mortars were assessed by determination of the apparent volume mass, mechanical properties, such as compressive and bending strength, water absorption, whereas their self-cleaning capacity was measured by methylene blue degradation test under UV and solar irradiation. The results obtained show degradation effects in the mortar samples due to aging after each test, and indicated that mortars with perlite and nano-TiO2 are the best-performing ones, both from the durability and energetic point of view, rendering them suitable for applications in the green building sector and the conservation of cultural heritage.

Development of Photocatalytic 3D-Printed Cementitious Mortars: Influence of the Curing, Spraying Time Gaps and TiO2 Coating Rates

“…Titanium dioxide (TiO 2 ) holds particular features, such as high chemical stability, high oxidation-reduction capacity, non-toxicity, and is available at a lower price, besides being the most employed semiconductor in photocatalytic materials [2,3,8,[12][13][14][15][16][17]. TiO 2 is widely used in different fields for the purpose of water and air purification and self-cleaning [2,[18][19][20][21], including in civil engineering for cementitious materials (by, e.g., [3][4][5]7,17,[22][23][24][25]). The main factors that allow the cementitious materials an ideal support medium for semiconductors (and in particular TiO 2 ) are: (i) the porous structure of the cementitious mortar/concrete bulk [4,9,24]; (ii) the strong binding ability of the cementitious materials [9,17]; as well as (iii) the compatibility between TiO 2 particles with the alkaline nature of cementitious materials [6,9].…”

New chronology of medieval objects in the Northern Black Sea region according to the method of determining calcite main peak intensity

“…This indicator can be used in the general structural assessment of historic stone buildings. Determination of the characteristics and durability of mortars for their correct use and preservation of architectural monuments and historical heritage was carried out by Fernandez F. et al [20]. They studied the solutions based on limemetakaolin and hydraulic lime -metakaolin with the addition of nano-TiO2and perlite.…”

Physical and Mechanical Characterization of Lime Pastes and Mortars for Use in Restoration

“…Regarding the knowledge of the performance and possibilities of lime as a construction material, it is necessary to know its manufacturing process and traditional application techniques [7]. Furthermore, it is important to understand the durability properties and behavior of the material against inclemency, as well as its own characteristics [8]. The restoration of historic buildings is a complex process that requires much effort and a large workforce to repair and preserve the architectural elements [9].…”