This paper focuses on the study of different Roman mortars (renders, finishing coats), used in the construction and restoration of the Forum Traiani thermal baths (Central Sardinia, Italy), a significant example of the Roman-style architecture in Sardinia. The archaeological site is located in a high hydrogeological risk area, due to the cyclical flooding of nearby Tirso river. Moreover, the presence of thermal saline (NaCl-bearing) water spring directly in contact with mortars and building stones, also contributed to structure degradation. An analytical approach, comprising mineralogical-petrographic characterization, physical analysis and particle-size distribution of aggregate, was used for mortars characterization. In addition, pXRD analysis on mortars defined the presence of alteration minerals while the thermal characterization (TGA) gave information about binder hydraulicity degree. Further μ-XRD-associated μ-Raman spectroscopy and μ-FTIR were utilized for pigments identification on frescos. Interesting results came from two wall stratigraphic series of mortars, highlighting construction stages, ancient restoring interventions and waterproofing methods. The main pigments used on red, yellow and black frescoes were red ochre, goethite and wood charcoal respectively.

中文翻译：

---

水文地质风险地区古迹中罗马灰浆的古代修复和生产技术：案例研究

本文重点研究用于论坛Traiani论坛的建筑和修复的各种罗马灰浆（装饰物，饰面层）热水浴（意大利撒丁岛中部），是撒丁岛罗马风格建筑的重要代表。由于附近的蒂尔索河（Tirso river）的周期性洪水，考古遗址位于水文地质风险高的地区。此外，直接与砂浆和建筑石材接触的热盐水（含NaCl）水的存在，也导致结构退化。砂浆的表征采用分析方法，包括矿物岩石学表征，物理分析和骨料粒度分布。另外，对灰浆的pXRD分析确定了蚀变矿物的存在，而热定性（TGA）给出了有关粘合剂水硬性程度的信息。进一步将与μ-XRD相关的μ-拉曼光谱和μ-FTIR用于壁画上的颜料鉴定。有趣的结果来自砂浆的两个墙地层系列，突出了施工阶段，古老的修复措施和防水方法。红色，黄色和黑色壁画上使用的主要颜料分别是红red石，针铁矿和木炭。