The effects of an historical fire were studied on a porous calcarenite coming from an historic building located in Southern Italy. Changes of material properties were investigated on the masonry blocks affected by fire in comparison with the sound stone. They were also compared with thermally induced degradation under controlled heating in laboratory conditions.

The stone was affected by a pronounced aesthetical damage consisting of gray and red discoloring. This was the effect of mineralogical-chemical phase transitions, which were detected by diffractometric and thermal analyses. The transformation of goethite to hematite accounted for changes from the original pale yellow color to red. Gray discoloring was found related to burning of organic matter and formation of magnetite. Damage on the stone microstructure was detected by SEM in the form of micro-cracks. It was also investigated through non-destructive ultrasonic propagation velocity tests, which recorded velocity decreases between 6% and 26%. Microfissuring left almost unchanged the bulk density and porosity measured by buoyancy and saturation techniques, as well as the mechanical properties. The latter were assessed by uniaxial compressive tests. A combined experimental protocol, including colorimetry, non-destructive testing and mechanical testing was used to compare the samples conditioned at high temperature in a laboratory environment with those affected by the real fire. The results allowed to estimate that the maximum temperatures within the stone during fire were under 600 °C, up to 300 °C at a depth of about 8 cm.

High porosity of the stone accounts for a limited stone damage at microstructural level and consequent low effects on physical-mechanical properties. On the contrary, in the presence of macrocracking due to the thermal shock experienced by the stone in some areas during fire, an UPV decrease of approximately 40% and significant strength reductions between 46 and 55% were found.

历史火灾对来自意大利南部一座历史建筑的多孔方钙石的影响进行了研究。与完好的石材相比，研究了受火影响的砌块材料特性的变化。它们还与实验室条件下受控加热下的热诱导降解进行了比较。

这块石头受到了明显的美学损害，包括灰色和红色变色。这是矿物学-化学相变的影响，可通过衍射和热分析检测到。针铁矿向赤铁矿的转变导致了从原来的淡黄色变为红色的变化。发现灰色变色与有机物的燃烧和磁铁矿的形成有关。通过SEM以微裂纹的形式检测石材微观结构上的损坏。它还通过无损超声波传播速度测试进行了调查，记录的速度下降了 6% 到 26%。微裂隙几乎没有改变通过浮力和饱和技术测量的体积密度和孔隙率，以及机械性能。后者通过单轴压缩试验进行评估。使用包括比色法、无损检测和机械测试在内的组合实验方案，将实验室环境中高温条件下的样品与受实际火灾影响的样品进行比较。结果允许估计，火灾期间石头内的最高温度低于 600°C，在约 8 厘米的深度高达 300°C。

石材的高孔隙率导致微观结构水平上的石材损坏有限，因此对物理机械性能的影响较小。相反，在火灾期间石材在某些区域受到热冲击而出现宏观裂纹的情况下，发现 UPV 降低了约 40%，强度显着降低了 46% 至 55%。