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Article

Unveiling the Fire Effects on Hydric Dynamics of Carbonate Stones: Leeb Hardness and Ultrasonic Pulse Velocity as Capillary Coefficient Predictors

by
Roberta Lobarinhas
1,
Amélia Dionísio
2,* and
Gustavo Paneiro
2
1
CERENA, Técnico Lisboa, ULisboa, 1049-001 Lisboa, Portugal
2
DER/CERENA, Técnico Lisboa, ULisboa, 1049-001 Lisboa, Portugal
*
Author to whom correspondence should be addressed.
Appl. Sci. 2025, 15(15), 8567; https://doi.org/10.3390/app15158567
Submission received: 10 July 2025 / Revised: 25 July 2025 / Accepted: 29 July 2025 / Published: 1 August 2025
(This article belongs to the Special Issue Non-Destructive Techniques for Heritage Conservation)
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Abstract

Natural carbonate stones such as limestones and marbles are widely used in heritage and contemporary architecture, yet their durability is increasingly threatened by wildfire-related thermal stress. Since water transport plays a key role in stone deterioration, understanding how high temperatures affect hydric behavior is critical for conservation. This study investigates thirteen Portuguese carbonate lithotypes (including marbles, limestones, a travertine, and a breccia) exposed to temperatures of 300 °C and 600 °C. Capillary absorption and open porosity were measured, alongside Leeb hardness (HL) and ultrasonic pulse velocity (UPV), to evaluate their predictive capacity for post-fire moisture behavior. Results show that thermal exposure increases porosity and capillary uptake while reducing mechanical cohesion. Strong correlations between UPV and hydric parameters across temperature ranges highlight its reliability as a non-invasive diagnostic tool. HL performed well in compact stones but was less consistent in porous or heterogeneous lithologies. The findings support the use of NDT tests, like UPV and HL, for rapid post-fire assessments and emphasize the need for lithology-specific conservation strategies.

1. Introduction

Natural stones have historically played a central role in architecture, not only due to their availability and esthetic appeal but also because of their durability and environmental performance [1,2,3]. Their presence in both culturally significant buildings and contemporary constructions underlines their relevance as a building material [4]. However, stone is not immune to degradation. A wide range of deterioration mechanisms can affect its integrity, depending on environmental and contextual factors [5]. For instance, surface flaking has been linked to high-temperature exposure, but similar patterns have also been observed in heritage contexts unrelated to fire [6], highlighting the complexity and diversity of these processes. Over time, deterioration can be triggered by multiple factors, including pollution, biological colonization, salt crystallization, mechanical stress, and increasingly, climate-induced hazards such as wildfires [7,8,9,10,11,12]. Although stone itself is a noncombustible material, climate change alters the surrounding environment in ways that exacerbate its decay. For example, elevated temperatures and reduced humidity promote the frequency and intensity of wildfires, which can lead to irreversible damage in stone structures, particularly in heritage contexts [13,14,15,16]. The severity of fire-induced damage depends on the stone’s lithological properties, like mineralogical composition, grain size, fabric, and porosity, all of which influence its thermal response [17,18]. Carbonate stones such as limestones and marbles are especially sensitive due to the anisotropic thermal behavior of calcite, their dominant mineral phase. Calcite undergoes anisotropic expansion from approximately 200–300 °C, leading to transgranular and intergranular microcracking, with more severe transformations including decarbonation and porosity increase, occurring above 600 °C [19,20,21,22,23]. These thermal alterations compromise both mechanical strength and water-related properties such as capillary absorption [24,25].
Water plays a critical role in stone deterioration. Capillary uptake introduces moisture into the porous network, triggering degradation processes such as freeze–thaw cycles, salt crystallization, swelling of clay minerals, and enhancing biological colonization [26,27,28,29]. The extent and severity of these processes are closely related to stone’s internal structure, particularly its porosity, fissure network, and mineralogical composition. When stones are exposed to high temperatures, as in fire scenarios, their microstructure can undergo significant transformations, such as pore enlargement and crack formation, creating new porosity structures that further influence their vulnerability to moisture-related decay [30,31]. Assessing these internal changes is essential for understanding post-fire behavior, especially in complex lithologies where traditional visual inspection may not reveal the full extent of damage and in situations where water can be present.
To address this challenge, non-destructive testing (NDT) techniques have emerged as valuable tools for evaluating stone condition without compromising material integrity. Their application is particularly relevant in heritage conservation and construction, where invasive methods are often restricted [32]. Among the various NDT tools available, ultrasonic pulse velocity (UPV) and Leeb hardness (HL) stand out due to their practicality, sensitivity to internal changes, and potential for correlation with key petrophysical properties. UPV has shown strong correlations with the presence and propagation of internal fissures, porosity, and early-stage weathering in carbonates [33,34,35]. HL, originally developed for metal materials, has been adapted for use on rocks and demonstrated potential as a predictor of uniaxial compressive strength (UCS) in various lithologies [36,37,38,39,40,41,42]. Notably, HL offers reliable and consistent readings, and is almost unaffected by surface roughness, although its readings can be influenced by factors such as moisture content, texture, and ambient temperature fluctuations [43,44].
Recent studies have shown that, in rock materials, both HL and UPV values decrease with increasing porosity and crack density [45,46,47], suggesting that they could also be indirectly linked to hydric performance parameters such as capillary water absorption. However, the current literature emphasizes their role as predictors of mechanical strength [48,49] and, to date, neither have been directly applied to estimate capillary water behavior. Yet moisture transport plays a critical role in stone degradation, as it can accelerate or trigger subsequent mechanical damage, particularly in thermally altered materials. In light of the increasing frequency and severity of wildfires, coupled with the critical need for reliable, non-destructive diagnostic methodologies, this study rigorously evaluates the viability of Leeb hardness and ultrasonic pulse velocity measurements as proxies for predicting the hydric behavior of carbonate stones subjected to high-temperature exposure. For this, a total of thirteen carbonate lithotypes, including marbles, limestones, a travertine, and a breccia, were studied before and after thermal exposure at 300 °C and 600 °C. These two temperature thresholds were selected to capture distinct stages of thermal alteration in carbonate stones. At 300 °C, thermal expansion of calcite may contribute to crack closure due to differential stress redistribution [50], whereas at 600 °C, the same process is more likely to promote the formation of new microcracks and porosity increase [48], although this is still well below the calcination temperature of calcium carbonate (approximately 897 °C) [51]. Together, these two conditions provide a representative spectrum into both moderate and advanced fire-induced degradation scenarios. Petrophysical properties such as open porosity, bulk density, and capillary absorption coefficient were measured. By bridging the gap between mechanical diagnostics and moisture behavior, this work contributes to the development of more comprehensive assessment strategies for stone conservation under changing climatic conditions.

2. Materials and Methods

Thirteen Portuguese carbonate stones were selected for this study, comprising limestones (AV, BG, BM, BML, EN, HB, LZ, MC), marbles (MB, MR, RV), a breccia (B), and a travertine (TV) (Figure 1). The selection aimed to represent a wide range of textures, porosity levels, and microstructural features, while focusing on lithologies of both cultural heritage relevance and commercial importance. All stones are used in traditional and contemporary construction in Portugal and abroad. Their main petrographic characteristics are summarized in Table 1.
Fifteen cubic specimens (50 mm) were prepared from each of the thirteen carbonate lithologies, totaling 195 samples. These were divided into three groups: unheated references and samples exposed to 300 °C and 600 °C. Heating was performed in a programmable muffle furnace, with a ramp rate of 12 °C/min and 3 h exposure time at target temperatures. The specimens were then cooled by 10 s tap water immersion at 20 °C to simulate one of the most common fire extinguishing techniques, i.e., water suppression. All samples were subsequently cooled down in environmental conditions. Reference samples were kept unheated under the same conditions.
Open porosity was determined according to EN 1936 [52]. Capillary absorption tests followed EN 1925 [53], with capillary coefficients calculated from the linear portion of the absorption curve. Ultrasonic pulse velocity (UPV) was measured following the updated ISRM Suggested Method for Determining Sound Velocity by Ultrasonic Pulse Transmission Technique [54], using contact p-wave transducers installed on opposite specimen faces with Vaseline as a coupling agent. Electric pulses (50 Hz frequency) were generated using a BK Precision 5 MHz Function Generator (BK Precision, Yorba Linda, California), and signals were received and analyzed using a Rohde & Schwarz HMO1002 (Rohde & Schwarz, Munich, Germany) oscilloscope to determine the travel time of the first wave arrival. Leeb hardness (HL) was assessed using a SAUTER HN-D hardness tester equipped with a standard D-type impact device (Sauter, Freiburg im Breisgau, Germany) (tip mass 5.5 g, impact energy 11 mJ), following a single-impact protocol adapted from ASTM E140 [55]. Although this method is standardized for metals, it is commonly applied to rock materials due to its demonstrated correlation with compressive strength. In this study, single impacts were applied at different points on specimens with diameters ≥50 mm to avoid scale and edge effects. A consistent measurement grid was applied to each specimen face to ensure representativeness, with six impacts per face, repeated five times. The average value per face was calculated, prioritizing top and bottom surfaces aligned with the capillarity test direction. In total, 11,700 measurements were performed across all samples, resulting in 1950 average values used in the correlation analysis. The extensive repetition for each specimen enhanced repeatability and minimized measurement uncertainty. The minimal variation among repeated impacts on each face further demonstrates the reliability of HL as a consistent NDT parameter in this study and strengthens confidence in the observed correlations. To assess the relationships between NDT results and capillary coefficients, multiple fitting models were tested, including linear, logarithmic, polynomial, and exponential models. For each lithotype and parameter pair, the model yielding the highest coefficient of determination (R2) was selected and used to represent the correlation.

3. Results and Discussion

Open porosity predominantly increases with temperature across all lithologies (Figure 2). This trend clearly reflects thermally induced microcracking and structural degradation [56,57]. Limestones display variable sensitivity, with some (e.g., MC, BG) showing marked open increases, while others (e.g., EN, LZ) exhibit only minor porosity, indicating greater structural resilience to thermal stress. Marbles exhibit limited open porosity change up to 300 °C, with an average increase of around 367%, which becomes significantly aggravated at 600 °C, reaching a mean rise of approximately 1300%. Travertine and breccia show the highest open porosity gains, particularly travertine, indicating their high susceptibility, mostly due to irregular and porous internal structures. These results underline that thermal exposure significantly alters open porosity—especially in stones with pre-existing heterogeneity like breccia—and/or weakens grain contacts, as observed in marbles.
Open porosity increase promoted by thermal fissuration processes is known to impact the capillary coefficient, as such microstructural discontinuities promote faster water ingress in natural stones [58]. This connection is reinforced by previous studies emphasizing the influence of micro-fissures and elongated pores in enhancing preferential water pathways [59,60]. Given that capillary action is governed by surface tension forces and the interaction between water and pore surfaces, structural anisotropy can impose a directional dependence in moisture uptake [61,62,63].
The correlation between Leeb hardness (HL) and capillary coefficients varies significantly across the studied lithologies (Figure 3). Among the limestones (Yellow Group on Figure 3), the predictive performance of HL varied widely. Some lithologies, such as BM (R2 = 0.87), BML (R2 = 0.79), HB (R2 = 0.75), and AV (R2 = 0.72), demonstrated strong exponential fits, while others, like EN (R2 = 0.29) or MC (R2 = 0.49), revealed weaker or more scattered responses. These differences can be attributed to the presence of variable structures such as stylolites and grain alignments (Figure 4a,b), which can influence the cracking pattern and are not fully captured by a surface technique like Leeb hardness. Marbles (Pink Group on Figure 3) showed notably higher consistency. Both MR and RV reached R2 values of 0.91, while MB displayed the highest fit at R2 = 0.94. This can be explained by the generally lower porosity and higher textural homogeneity of marbles, which enhances HL sensitivity to microstructural change and reduces data dispersion (Figure 4c,d).
In contrast, HL showed poor predictive capacity for the breccia (Blue Group on Figure 3, B: R2 = 0.13) and the travertine (Green Group on Figure 3, TV: R2 = 0.13). These lithologies are highly heterogeneous in terms of pore geometry and distribution, with irregular textures that weaken the mechanical response consistency. As such, HL measurements on these stones were less representative of internal damage affecting capillarity.
These results aligned with previous bibliography that states that marbles, by having low porosity, high crystallinity, and granoblastic texture, lead to more predictable energy dissipation and uniform damage propagation under thermal stress [20]. This reflects a practical limitation of HL in porous or heterogeneous stones, where rebound energy loss at the surface reduces its consistency as an indicator of internal structural changes, particularly those affecting capillarity.
Similarly to the assessment of Leeb hardness, the correlation between ultrasonic pulse velocity (UPV) and capillary coefficients exhibited varying degrees of strength across the studied lithologies, although with generally stronger correlations overall (Figure 5).
Among the limestones (Yellow Group on Figure 5), UPV achieved consistently strong correlations with water absorption by capillarity: BM (R2 = 0.97), BG (R2 = 0.96), and BML (R2 = 0.90). Interestingly, in this assessment, EN presented a R2 value of 0.93, unlike the previous one obtained for HL (R2 = 0.29). These results confirm that UPV is highly sensitive to microstructural degradation, particularly that which influences water transport properties in the studied carbonate stones. MC limestone also experienced an R2 increase from 0.49 to 0.72, highlighting a consistency of a stronger relationship between this technique and water transport behavior.
Marbles (Pink Group on Figure 5) also experienced an increase in correlation values with this method, maintaining high predictive reliability already observed for Leeb hardness. MR and RV achieved R2 = 0.97 and R2 = 0.99, respectively, and MB closely followed with R2 = 0.94. These results reinforce the suitability of UPV for detecting capillarity-relevant changes in compact and crystalline lithologies, where ultrasonic wave velocity is tightly linked to cohesion and density. Interestingly, the breccia (Blue Group on Figure 5) exhibited a surprisingly good fit (R2 = 0.82), outperforming HL in the same lithology, with a previous R2 = 0.13. This change can be linked to the bulk-scale heterogeneity of breccias, where UPV better integrates spatial variability than surface-based methods. Conversely, the travertine (Green Group on Figure 5, TV: R2 = 0.09) once again showed negligible/nonexistent correlation. This suggests that the highly porous and heterogeneous structure of travertine interferes with the transmission of ultrasonic waves, making the results unreliable as indicators of capillary behavior. Compared to HL, UPV appeared to exhibit greater sensitivity and broader applicability across lithologies. The tighter clustering around fitted curves may suggest a more consistent relationship between UPV and capillarity-related deterioration under thermal stress.
These results are in line with prior research, which highlights the strong sensitivity of UPV to internal degradation mechanisms such as microcracking, loss of cohesion, and increased pore connectivity [47,64]. The strong inverse correlations found in limestones and marbles reflect the parallel evolution of structural weakening and water ingress capacity. Lithologies exhibiting lower porosity and higher textural homogeneity present optimal conditions for UPV-based detection of thermal degradation affecting capillary transport properties. This aligns with previous studies showing that UPV performs best in compact carbonate rocks, where ultrasonic wave scattering is minimally affected by large voids or fabric anisotropy [46,64].
The significant UPV losses observed in thermally damaged marbles (up to 70% at 600 °C) are especially consistent with their increased capillary coefficients, reinforcing the reliability of this method in dense, crystalline matrices. In contrast, the limited predictive capacity observed in more heterogeneous stones (like travertine) is consistent with known limitations of UPV in porous and anisotropic media, where wave propagation is highly influenced by structural irregularities that do not necessarily correlate with water transport. Still, the ability of UPV to integrate large volumes of material helps mitigate local inconsistencies, providing more robust results than surface-limited techniques such as Leeb hardness, especially in heterogeneous stones (like breccia).
To complement the lithology-based assessment, an analysis segmented by thermal exposure (reference, 300 °C, and 600 °C) was conducted to explore how temperature influences the correlation between capillary coefficient and the two non-destructive techniques. This approach offers a broader view of method reliability across progressive stages of thermal degradation (Figure 6). It must be mentioned that the travertine (TV) was excluded from this analysis. As demonstrated in previous sections, both HL and UPV failed to show meaningful correlation with capillary behavior (R2 ≈ 0.13 and 0.09 correspondingly), which is attributed to its highly porous, anisotropic, and irregular internal structure. These features disrupt ultrasonic wave transmission and mechanical rebound dynamics, leading to inconsistent readings that are not representative of internal hydric changes. In this context, travertine’s unique fabric falls outside the sensitivity range of these methods.
As illustrated in the plots (Figure 6), UPV exhibited a robust inverse correlation with the capillary coefficient across all temperature stages, with a global fit of R2 = 0.71. When analyzing temperature ranges separately, it is visible that its predictive capacity improved with increasing temperature, reaching R2 = 0.52 at 600 °C, still lower than the global fit, reflecting better results, when considering all the temperature conditions, than the individual analysis. HL, in contrast, displayed more modest global performance (R2 = 0.52), with a lower fit at 300 °C (R2 = 0.37) and reduced reliability also at 600 °C (R2 = 0.43).
These results reflect the underlying physical mechanisms governing each technique’s response to thermal alteration. At reference conditions, the stone’s internal cohesion and pore framework remain largely unaffected, and water movement is mostly controlled by intrinsic textural attributes such as grain size, porosity type, and mineral arrangement, rather than structural discontinuities [24,65]. While both techniques apply to intact materials, their limited correlation with capillarity at this stage suggests that subtle textural variations are not effectively captured, particularly in the absence of thermally induced damage. Above 300 °C, the development of microcracking becomes more significant, mainly driven by calcite’s anisotropic thermal expansion [66]. This microstructural evolution increases the interdependence between mechanical degradation and moisture transport. In this context, UPV gains relevance due to its volumetric measurement principle; the ultrasonic wave propagates through the specimen and integrates internal changes such as crack formation and pore network evolution, providing a broader representation of damage. HL, on the other hand, relies on surface rebound dynamics and is more affected by localized features, such as roughness, grain boundary exposure, or isolated voids, which may not correspond well to bulk structural changes [67]. While this study focused on uniform heating, the observed porosity increases and microcracking aligns with patterns reported under localized thermal exposure, such as laser irradiation. Similar cracking behavior has been observed in laser-irradiated limestones subjected to high temperatures [68], supporting the potential applicability of these findings to non-uniform thermal stress scenarios.

4. Conclusions

This study assessed the effects of fire-induced thermal exposure on the hydric behavior of thirteen Portuguese carbonate stones and evaluated the ability of two non-destructive techniques, Leeb hardness (HL) and ultrasonic pulse velocity (UPV), to predict capillary water uptake under these altered conditions. Thermal damage was shown to significantly increase porosity and capillary absorption, especially above 300 °C. These changes result from microcrack propagation and anisotropic mineral expansion, which progressively compromise the stone’s mechanical integrity. Among the techniques, UPV consistently demonstrated superior predictive capacity across lithologies and temperature ranges. Its volumetric sensitivity allowed it to capture internal degradation that directly influenced water transport. HL, while effective in dense and homogeneous stones like marble, showed limited performance in heterogeneous lithologies and at higher temperatures. Travertine, due to its anisotropic pore network, was excluded from the temperature-based regression analyses. While this highlights a limitation in the applicability of HL and UPV to highly heterogeneous stones, it also emphasizes the need to investigate complementary methods capable of more effectively resolving internal pore structures and water dynamics in such complex lithologies.
Importantly, this research extends the application of HL and UPV beyond mechanical diagnostics, demonstrating their potential as non-invasive proxies for water transport behavior after fire events. These insights are especially pertinent in the context of increasing climate variability, where the frequency and intensity of extreme phenomena like wildfires are expected to rise. In this regard, the study contributes to a better understanding of how thermally induced damage can affect stone performance not only structurally, but also in terms of moisture regulation, a key factor in building conservation. In particular, UPV stands out as a practical field tool for post-fire diagnostics, especially in heritage contexts where invasive testing is restricted. Its volumetric sensitivity, portability, and ability to detect internal degradation without damaging the material make it especially valuable for rapid, in situ assessments. Ultimately, these findings support improved heritage risk evaluation and the deployment of efficient diagnostic strategies in conservation practice.

Author Contributions

Conceptualization, R.L., A.D. and G.P.; methodology, R.L.; validation, R.L., A.D. and G.P.; formal analysis, R.L., A.D. and G.P.; investigation, R.L.; data curation, R.L.; writing—original draft preparation, R.L., A.D. and G.P.; writing—review and editing, R.L., A.D. and G.P.; supervision, A.D. and G.P.; project administration, A.D. and G.P.; funding acquisition, A.D. and G.P. All authors have read and agreed to the published version of the manuscript.

Funding

This research was funded by CERENA (FCT-UIDB/04028/2025 and FCT-UIDP/04028/2025), grant number UI/BD/152298/2021.

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

The raw data supporting the conclusions of this article will be made available by the authors on request.

Conflicts of Interest

The authors declare no conflicts of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results.

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Figure 1. Representative surfaces of the thirteen studied carbonate lithotypes: AV—Azul Valverde; LZ—Lioz; EN—Encarnadão; MC—Moca Creme; BML—Beige Medium Light; BM—Beige Medium; HB—Hardblue; MB—Estremoz Branco; MR—Estremoz Rosa; RV—Ruivina; B—Arrábida Breccia; and TV—Travertine. Photographs correspond to polished reference samples of a 10 × 10 cm slab.
Figure 1. Representative surfaces of the thirteen studied carbonate lithotypes: AV—Azul Valverde; LZ—Lioz; EN—Encarnadão; MC—Moca Creme; BML—Beige Medium Light; BM—Beige Medium; HB—Hardblue; MB—Estremoz Branco; MR—Estremoz Rosa; RV—Ruivina; B—Arrábida Breccia; and TV—Travertine. Photographs correspond to polished reference samples of a 10 × 10 cm slab.
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Figure 2. Bar plots with porosity values (%) for the thirteen carbonate stones at reference conditions, 300 °C, and 600 °C. Lithologies are grouped by lithology: limestones, marbles, breccia, and travertine. Error bars represent standard deviation.
Figure 2. Bar plots with porosity values (%) for the thirteen carbonate stones at reference conditions, 300 °C, and 600 °C. Lithologies are grouped by lithology: limestones, marbles, breccia, and travertine. Error bars represent standard deviation.
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Figure 3. Scatter plots showing the relationship between Leeb hardness (HL) and capillary coefficient for the studied carbonate stones.
Figure 3. Scatter plots showing the relationship between Leeb hardness (HL) and capillary coefficient for the studied carbonate stones.
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Figure 4. Image documentation of selected stone features: (a) stylolites in EN limestone; (b) mineral alignments in MC limestone; (c) petrographic thin section of MB marble in crossed nicols; (d) petrographic thin section of RV marble in crossed nicols.
Figure 4. Image documentation of selected stone features: (a) stylolites in EN limestone; (b) mineral alignments in MC limestone; (c) petrographic thin section of MB marble in crossed nicols; (d) petrographic thin section of RV marble in crossed nicols.
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Figure 5. Scatter plots showing the relationship between ultrasonic pulse velocity (UPV) and capillary coefficient for the studied carbonate stones.
Figure 5. Scatter plots showing the relationship between ultrasonic pulse velocity (UPV) and capillary coefficient for the studied carbonate stones.
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Figure 6. Relationship between capillary coefficient and non-destructive parameters: (a) global correlation with UPV; (b) UPV correlation segmented by temperature; (c) global correlation with HL; (d) HL correlation segmented by temperature. Colored points represent mean values per lithology and thermal condition.
Figure 6. Relationship between capillary coefficient and non-destructive parameters: (a) global correlation with UPV; (b) UPV correlation segmented by temperature; (c) global correlation with HL; (d) HL correlation segmented by temperature. Colored points represent mean values per lithology and thermal condition.
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Table 1. Petrographic description of the stones studied.
Table 1. Petrographic description of the stones studied.
NameTypePetrographic Description
Azul Valverde (AV)LimestoneFine-grained microcrystalline calciclastic and bioclastic limestone, bluish gray, with rounded and elongated micritic calcite (pellets) and sparitic calcite.
Arrábida Breccia (B)BrecciaBreccia composed of multicolored carbonate clasts cemented by a red, ferruginous clay-carbonate matrix.
Beige Grande (BG)LimestoneMicrosparitic limestone with a beige tone, containing peloids, fossils, and oolites.
Beige Medium (BM)LimestoneFine-grained beige limestone composed mainly of micritic calcite with scattered peloids and fossil fragments.
Beige Medium Light (BML)LimestoneBeige micritic limestone with intermediate grain size, containing peloids, sparitic calcite, and sparse fossil remains.
Encarnadão (EN)LimestoneReddish-pink microcrystalline limestone. Biopelmicrosparite with stylolitic structures filled with carbonate minerals.
Hardblue (HB)LimestoneFine-grained grayish-blue limestone, composed of micritic calcite and sparitic cement, with peloids and fossil remains.
Lioz (LZ)LimestoneMicrocrystalline fossiliferous limestone with various fossil content, including rudist fossils.
Estremoz Branco (MB)MarbleWhite marble with a granoblastic texture, composed of equidimensional calcite crystals.
Moca Creme (MC)LimestoneLight beige bioclastic limestone, composed of micritic calcite and sparitic cement, with peloids, fossils, and occasional oolites.
Estremoz Rosa (MR)MarblePink-colored marble with a fine to medium grain size.
Ruivina (RV)MarbleDark gray to black marble with a fine grain size, occasionally displaying foliated textures due to biotite and chlorite minerals.
Condeixa Travertine (TV)TravertineTufa limestone with a beige-brown color and a concretionary texture.
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Lobarinhas, R.; Dionísio, A.; Paneiro, G. Unveiling the Fire Effects on Hydric Dynamics of Carbonate Stones: Leeb Hardness and Ultrasonic Pulse Velocity as Capillary Coefficient Predictors. Appl. Sci. 2025, 15, 8567. https://doi.org/10.3390/app15158567

AMA Style

Lobarinhas R, Dionísio A, Paneiro G. Unveiling the Fire Effects on Hydric Dynamics of Carbonate Stones: Leeb Hardness and Ultrasonic Pulse Velocity as Capillary Coefficient Predictors. Applied Sciences. 2025; 15(15):8567. https://doi.org/10.3390/app15158567

Chicago/Turabian Style

Lobarinhas, Roberta, Amélia Dionísio, and Gustavo Paneiro. 2025. "Unveiling the Fire Effects on Hydric Dynamics of Carbonate Stones: Leeb Hardness and Ultrasonic Pulse Velocity as Capillary Coefficient Predictors" Applied Sciences 15, no. 15: 8567. https://doi.org/10.3390/app15158567

APA Style

Lobarinhas, R., Dionísio, A., & Paneiro, G. (2025). Unveiling the Fire Effects on Hydric Dynamics of Carbonate Stones: Leeb Hardness and Ultrasonic Pulse Velocity as Capillary Coefficient Predictors. Applied Sciences, 15(15), 8567. https://doi.org/10.3390/app15158567

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