Issues related to climate change make it difficult to save architectural design for the future, as it deteriorates in different ways depending on which side of the building it is on. This uneven decay is attributed to agents of directional weathering like wind, solar radiation, and wind-borne water like rain that impacts certain parts of a structure. Unlike vector climatic elements, which act on the building along the direction, scalar climatic elements, such as temperature and humidity, affect buildings uniformly (Martínez-Martínez et al. 2024). This being the case, the function of preventive conservation is to decrease irreversible harm through the recognition of the places where weathering is most prodigious. That is why, through the evaluation of erosion anisotropy, the study will try to outline efficient steps to protect monuments similar to the Cerrillos Tower in Spain. This methodology shares essential principles with the United Nations 2030 Agenda for Sustainable Development.
The coastal Cerrillos Tower, a 16th-century orientated watch tower located close to Cenbergue in southeastern Spain close to Almería, is ideal for anisotropic erosion pattern analysis. The height of the building is 11 meters, and stone and lime mortar are constructed in progressive rings. It lies on a sandy strip along the Mediterranean Sea shore and lagoons, which makes it vulnerable to natural factors such as wind, seawater, and random and semi-arid climatic conditions. Due to the nature of the building, which is exposed to all types of weather and devoid of any protective barriers such as shielding walls, the tower can well be used to illustrate how the erosion process affects Mediterranean heritage structures.
The Weathering Anisotropy Analysis methodology used for the Cerrillos Tower includes four significant techniques to measure the deterioration at the complex, such as thematic cartography, material evaluation during the works, laboratory analyses, and environmental exposure. Contour maps portray the degree of erosion and biological incorporation, and material density is quantified at 28 sites using non-destructive tests such as Leeb Hardness and Ultrasonic Pulse Velocity. The analysis of stone, mortar, and salt samples reveals the susceptibility of building material. Localized airflow, humidity, and UV exposure are assessed as vectors influencing the rate of the tower’s degradation. Such an integrated approach is helpful in defining the types and rates of weathering as well as in formulating the appropriate conservation measures.
It has been observed that because of the type of material and design construction of this Cerrillos Tower, it is more affected differently in terms of weathering. The outer ashlar layer is yellowish-ochre biocalcarenite with high permeability and frequent facies changes, the fragments of which are red algae and bivalves (Martínez-Martínez et al. 2024). The mortar, which is lime and sand aggregates, has disintegrated, especially in the regions that are affected by moisture and salt. These characteristics include high porosity and, hence, low mechanical strength and resistance to deterioration through salt crystallization cycles. That is why the differential erosion process becomes the destabilizer of such structures; for example, through the erosion action of the mortar, the stone blocks get detached. These vulnerabilities clearly show why concrete steps must be taken for the conservation of the tower.
The weathering and erosion factors that have befallen the Cerrillos Tower are mainly the differentiation of halite crystals and thermal expansion. Hence, the salt entering the porous materials is worn out by sea spray and capillary action at both the lower and upper parts of the tower (Martínez-Martínez et al. 2024). Halite is the cause of surface decay due to crystallization, together with the stone’s pores, caused by daily fluctuations in temperature. Further, the mortar between the masonry wears out and thus causes the detachment of rock blocks that are involved in the construction. The combined effect of salt damage and thermal expansion leads to extensive de-lamination of the structure of the exposed stone with a maximum rate of erosion in places that receive direct sunshine and wind blow. Wind also blows abrasive particles and hence escalates the erosion, particularly on the lowermost levels of the tower. This anisotropy of the eroded patterns, due to climatic factors, reveals the necessity of specific conservation measures establishing shelters from solar radiation, wind, and sea aerosols.
In conclusion, the proposed methodology that links climate analysis and the thematic maps of the region with the material analysis of the artifacts aims to define the main climatic hazards threatening the cultural heritage. It showed significant regional directional erosion tendencies in relation to the wind, rain, and solar exposure of the project to the South and East directions when this approach was applied to the Cerrillos Tower. With respect to the role of solar radiation, the analysis raised an issue of enhancing thermal oscillations and differential expansion between salts and porous materials. These effects can be minimized by preventive conservation interventions like placing barriers in specific directions; thus, the techniques of conservation and renewable energy are cost-effective strategies for climbing up to rising climate change challenges.
Reference
Martínez-Martínez, J., Benavente, D., Rocca, R., de los Ríos, A., & Gómez-Heras, M. (2024). Erosion anisotropy analysis of construction materials as a key tool for strengthening preventive conservation strategies inbuilt heritage. Construction and Building Materials, 449, 138530. https://doi.org/10.1016/j.conbuildmat.2024.138530
