Search

Santa Pudia limestone, a biocalcarenite highly sensitive to decay, is one of the most commonly used building materials in historical monuments in the city of Granada, Spain. The compatibility between a variety of stone treatments (consolidants and/or water repellents) and this calcarenite was analyzed and the resulting improvement in durability assessed. To this end, a two-stage accelerated ageing process was implemented. In the first, freshly quarried, undamaged specimens were altered to resemble the weathered stone in buildings. The second was conducted after applying the various treatments to the artificially aged stone to test their effectiveness. While all the treatments studied (Tegosivin HL100, Silo 111, Estel 1100 and Tegovakon V) enhanced stone resistance to decay while barely affecting chromatic parameters, the most effective was Tegowakon V, as it provided the best results in the hydric tests on the limestone.

“Sierra Elvira stone” is one of the ornamental building stones most widely used in the historical monuments of eastern Andalusia. A Liassic age limestone, it appears in the central section of the Baetic Mountains and more specifically in the Middle Subbaetic domain. While the most common variety is a crinoid limestone, a micritic limestone of the same age has also been quarried, albeit in much smaller quantities. These stones form very thick beds, up to nearly 5 m deep, that run in consistently parallel lines and have a dip angle that facilitates quarrying. With petrographic, physical and mechanical properties that ensure stone strength and durability, it is a high quality building material suitable for both structural and ornamental purposes. These properties can be attributed to the minimal open porosity and concomitant excellent water resistance that characterize the stone, as well as to its high mechanical strength and low textural anisotropy, both elastic and mechanical. With such attributes, the stone can be successfully used for any number of purposes, including decorative stonework (portals, fountains, plinths), structural members (column shafts and bases) or urban curbing and paving. Intervention on Sierra de Elvira limestone structures should be limited to cleaning or repair, for consolidating or protective materials are scantly effective.

This work focuses on the chemical-mineralogical, textural and physical-mechanical properties of hydraulic lime mortars made with siliceous and calcareous aggregate. Mortars were cured at 60% and 90% of relative humidity, so as to assess the variability of mortar petrophysical properties in the hardened state due to the moisture conditions. The final aim was to determine the most adequate moisture conditions to be maintained during application and hardening of hydraulic mortars intended for repair interventions. We found out that using a calcareous aggregate and curing mortar at 90% of relative humidity give place to better textural and mechanical properties. However, these characteristics mostly depend on the maximum size of the aggregate grains, which should be smaller than 6 mm, in order to avoid the occurrence of mechanical discontinuities in the mortar.

We have studied the physical-mechanical behaviour of solid bricks treated with consolidants and/or water-repellents in accelerated aging tests to determine their durability. The bricks were manufactured with a quartz-rich clay lacking in carbonates to which was added small amounts of different additives (calcite, dolomite or sodium chloride). During the manufacturing process, we attempted to replicate solid bricks similar to those used in many Cultural Heritage buildings. We have concluded that silicon resin gives the best results, whatever the additive used, whereas acrylic resin gives the least satisfactory results.