Historically, cow dung has been widely used as a biostabilizer in earth building, although the scientific research on this subject is still limited. The available research provides evidence of the positive effects of this bioaddition on earthen blocks and plasters, as it improves their physical and mechanical properties and durability in water contact. The present research does not aim to characterize biostabilized earthen mortars or to explain the interaction mechanisms between the earth and cow dung components, because this topic has already been investigated. Instead, it aims to investigate strategies to optimize the collection and processing of cow dung so as to optimize their effects when used in earth-plastering mortars, as well as considering the effects of using them fresh whole, dry whole, and dry ground (as a powder); the effects of two different volumetric proportions of cow dung addition, 20% and 40% (of the earth + added sand); the effects of 72 h (fermentation-humid curing) before molding the biostabilized mortar; the influence of the cow diet; and the potential of reusing cow dung stabilized mortars. The results show that as the freshness of the cow dung increases, the mortar's durability increases under water immersion, as well as the mechanical and adhesive strength. Collecting cow dung fresh and drying (composting) it in a plastic container is more efficient than collecting cow dung that is already dry on the pasture. The cow diet and the use of dry (composted) cow dung, whole or ground into a powder, does not result in a significant difference. A 72 h period of humid curing fermentation increases the adhesive strength and durability under water. The proportion of 40% promotes better durability under water, but 20% offers greater mechanical and adhesive strength. Finally, cow dung addition does not reduce the reusability of the earth mortar. The new mortar obtained by remixing the mortar with water presents increased properties in comparison to the original reference mortar with no cow dung addition. Therefore, the contributions of this research are innovative and important, offering technical support in the area of biostabilized earth-plastering mortars. Furthermore, it is emphasized that cow dung addition can be optimized as an efficient traditional solution to increase the mechanical resistance, but especially to increase the durability of earth mortars when in contact with water. This effect is particularly important for communities lacking financial resources, but also reveals the possibility of using eco-efficient waste instead of binders obtained at high firing temperatures.

This study investigates the behavior of different earth mortar compositions when exposed to elevated temperatures, considering factors such as the mineralogical nature and volumetric fraction of the aggregates used. Earth mortars made from a combination of a silty-clay earth, silica-calcareous sand and fired red ceramic bricks waste were investigated. Density, thermal conductivity, ultrasonic wave velocity, flexural and compressive strength are determined at 200 degrees C, 400 degrees C, 600 degrees C and 600 degrees C. Results show that incorporating aggregates reduces linear shrinkage and bulk density. The use of fired brick waste reduces the density, thermal conductivity and ultrasonic wave velocity. As the temperature increases up to 600 degrees C, thermophysical properties of the mortars decrease but their compressive strength increases. At the temperature of 800 degrees C, the mortars with silica-calcareous aggregate show a significant degradation but the addition of fired brick waste reduces the damage. TG/DSC analysis and SEM observations provided a better understanding of the reactions. The results obtained can be used to optimize the performance of earth mortars at elevated temperatures.

The study presented here applied various analytical techniques to examine a small fragmented painted gypsum plaster with heart motifs discovered at the Sasanian site of Vigol, Central Iran, to identify the materials used to produce the plaster. The plaster and its paint layer were analysed by X-ray fluorescence, X-ray diffraction, optical microscopy, scanning electron microscopy-energy dispersive X-ray spectroscopy and micro-Raman spectroscopy methods. The results revealed that the plaster layer is made of gypsum with some impurities-mainly soil minerals-with the concentration of these impurities being less at the surface of the plaster. It was also discovered that the heart motifs were painted using minium red lead pigment. As the main damage to the plaster is fragmentation, conservation included joining the fragments and consolidating the surface of the plaster. Finally, a preservation box using transparent polycarbonate plates was designed and manufactured for the display and handling of the newly restored plaster.

As a key cultural relic protection unit in China, the site of the Lidu Shochu Workshop has suffered deformation damage such as structural loosening and material deterioration following archaeological excavations. By means of on-site geological investigation, engineering geological mapping, drilling and indoor tests, the geotechnical type and spatial distribution characteristics, geotechnical setting and chemical properties of water and soil of the site where the Lidu Shochu Workshop was located were studied, and the main destruction mechanisms of the site remains based on the structural characteristics of the geotechnical setting were analyzed in depth. The results of the present study show that: (1) The site remains is subject to a strong alternating wet and dry conditions due to the site's location within the influence of perched water, the increased evaporation caused by the archaeological excavation that removed the upper layers of rock and soil of the site remains, which allowed for the continuous upward transport of perched water by capillary action, and the dynamic changes in the water table; (2) Due to the compartmentalization of the surrounding setting and the low lateral runoff, the perched water tends to accumulate more soluble salts that lead to a higher mineralization; (3) During the upward transport of water by capillary action, the soluble salts in the perched water are concentrated, crystallized and precipitated under evaporation, resulting in the crystallization of salts on the masonry surface of the site proper, which are mainly magnesium sulphate and calcium sulphate (gypsum); (4) In the crystallization process, magnesium sulphate and calcium sulphate (gypsum) swell in volume and corrode and destroy brick, sandstone and bonding materials, resulting in plaster disruption, weakening or failure of the bond, which lead to structural loosening, spalling and deformation.