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Abstract The orthotropic anisotropy of sedimentary rocks has a significant impact on the force and deformation behavior of the project. In this paper, radial pressurization tests were carried out in the borehole in a typical northern karst area to obtain the deformation properties and orthotropic anisotropy of the rock masses. The test results showed that the deformation modulus and elastic modulus of the limestone rocks in the dam site area obeyed normal distribution. The deformation modulus was basically larger than the proposed deformation modulus of Class II rocks (10 GPa). The deformation behavior and anisotropy degree of the limestone showed a weak correlation with the elevation, but a strong correlation with the development density of the rock joints. The larger development density of the rock in the right bank test section leads to a larger degree of orthotropic anisotropy and frequency of occurrence.

In addition to the surrounding climatic environment, the intrinsic characteristics of the stones used in construction are a critical factor to understand a building’s conservation state and define the necessary planning and conservation management activities. The use of environmentally susceptible stones, such as carbonate stones, in heritage buildings can be especially problematic. The present investigation presents an overview of past research and contributes to identifying the types of carbonate stones used over time in Coimbra’s Old Cathedral in Portugal, which was classified as a National Monument and integrated into the Coimbra World Heritage site by UNESCO. Our mineralogical and chemical analyses revealed the use of carbonate stones from different quarries (Coimbra region), including Ançã limestone and dolostone (Porta Especiosa portal), Portunhos limestone and Outil limestone (in the perimeter of windows), and marlstones and Outil limestone (side facades). These stones, which were installed at various times during the construction and alteration of the monument, represent a great challenge for conservation planning due to their intrinsic vulnerability to adverse environmental conditions and pollution.

The topological attributes of fracture networks in limestone, subject to intense hydrodynamics and intricate geological discontinuities, substantially influence the mechanical and hydraulic characteristics of the rock mass. The dynamical evolution of fracture networks under stress is crucial for unveiling the interaction patterns among fractures. However, existing models are undirected graphs focused on stationary topology, which need optimization to depict fractures' dynamic development and rupture process. To compensate for the time and destruction terms, we propose the damage network model, which defines the physical interpretation of fractures through the ternary motif. We focus primarily on the evolution of node types, topological attributes, and motifs of the fracture network in limestone under uniaxial stress. Observations expose the varying behavior of the nodes' self-dynamics and neighbors' adjacent dynamics in the fracture network. This approach elucidates the impact of micro-crack behaviors on large brittle shear fractures from a topological perspective and further subdivides the progressive failure stage into four distinct phases (isolated crack growth phase, crack splay phase, damage coalescence phase, and mechanical failure phase) based on the significance profile of the motif. Regression analysis reveals a positive linear and negative power correlation between fracture network density and branch number to the rock damage resistance, respectively. The damage network model introduces a novel methodology for depicting the interaction of two-dimensional (2D) projected fractures, considering the dynamic spatiotemporal development characteristics and fracture geometric variation. It helps dynamically characterize properties such as connectivity, permeability, and damage factors while comprehensively assessing damage in rock mass fracture networks.

Introduction. The use of mineral additives in cement concrete compositions makes it possible to reduce the consumption of Portland cement, which, with increasing construction rates, reduces the negative impact on the environment during its production. However, the high cost and territorial limitation of the production of the most effective modifiers (microsilica, metakaolin) do not allow to satisfy the growing demand for them. The development of mineral additives from widely used raw materials will help solve the problem of the deficit of the most common additives, as well as to reduce the consumption of Portland cement. The mechanism of hardening of Portland cement with widespread mineral additives was studied in sufficient detail. At the same time, there are practically no works describing the processes of hydration of cement binder modified with mineral additives based on thermally activated clay and carbonate rocks.Materials and methods. The following mineral additives were used: thermally activated clay (Nikitskoye deposit, Saransk, Republic of Mordovia), dolomite (Elniki village, Republic of Mordovia), thermally activated mixture of clay and limestone (Atemar village, Republic of Mordovia). Using the method of X-ray phase analysis, the mechanisms of action of these mineral additives on hydration processes are considered.Results. It was established that the use of these mineral additives makes it possible to increase the degree of hydration of Portland cement and change the phase composition of the cement stone in a targeted manner.Conclusions. The data obtained indicate the prospects and relevance of the direction for the development of concretes with modifying additives based on thermally activated polymineral clays and carbonate rocks, which makes it possible to expand the range of modified cement composites produced today due to more complete use of the local mineral resource base.

Abstract This study addresses the comparative influence of physicochemical parameters on the dissolution of Pb and its levels in the groundwater of former Pb mining areas in Kabwe and non-mining areas in Lusaka, Zambia. This cross-sectional study analyzed 61 groundwater samples from hand pump boreholes using atomic absorption spectrometry. Physicochemical parameters were measured, including electrical conductivity (EC), temperature, total dissolved solids (TDS), and pH. Statistical analysis involved the Wilcoxon test, Spearman’s correlation, robust linear regression, Principal component analysis (PCA), and generalized additive models. Pb concentrations were particularly higher (p = 0.029; median = 0.131 mg/L) in mining areas compared to non-mining areas (median = 0.071 mg/L). The EC in the mining areas (median = 585 µS/cm) was significantly (p = 0.001) lower than those in the non-mining area (median = 1100 µS/cm). Likewise, TDS levels revealed a significant (p = 0.001) difference between the mining area (median = 303 ppm) and the non-mining area (median = 601 ppm). The median pH values for groundwater samples in the mining and non-mining areas were 6.96 and 7.27, respectively. Spearman’s rank correlation revealed a significant (rho = − 0.405; p = 0.036) inverse relationship between Pb concentrations and pH in non-mining areas. Robust linear regression and generalized additive models underscored a significant (p = 0.016) non-linear relationship between temperature and Pb across all areas, with the non-mining area demonstrating a significant (p = 0.003) non-linear relationship between temperature and pH concerning Pb. The study associates mining activities with increased Pb concentrations, underscoring it as a principal contamination source. In contrast, elemental dissolutions from the basement limestone with dolomite might increase Pb concentration in the non-mining areas. The observed positive relationship between temperature and pH in non-mining areas highlights its positive interactions with Pb mobility while temperature greatly influences Pb dissolutions in mining areas.

Abstract Biological activity, climate and pollution are responsible for the degradation of building stones, especially limestone, which is widely used in the Paris region. In order to determine the respective contribution of physicochemical and biological processes to the degradation of limestone, limestone specimens from the Père-Lachaise cemetery (Paris, France) were exposed for five years under different conditions: sheltered from or exposed to rain and in horizontal or vertical position. After exposure, the collected samples were characterized by light and electron microscopy, X-Ray diffraction and ion chromatography after elution. The results showed an intense biocolonization of the samples exposed to rain, while the sheltered samples were more affected by the pollution (soiling). The characterization of the bacterial and fungal communities using Next Generation Sequencing Illumina 16S for bacteria and ITS for fungi highlighted that five main bacterial phyla were identified: Actinobacteriota, Bacteroidota, Cyanobacteria, Proteobacteria and Deinococcota (major genera Flavobacterium, Methylobacterium-Methylobacter, Sphingomonas, Roseomonas and Nocardiodes). Among the fungi, the phylum Ascomycota was predominant with the genera Cladosporium, Ramularia, Aureobasidium and Lecania. However, the alteration of the limestone is difficult to quantify at this stage. Potassium nitrate of rain origin has been found in the sheltered area, but no gypsum. Therefore, the biocolonization is a fast phenomenon on the stone and the physico-chemical processes derived from it, caused by climate and pollution, are slower. This is in agreement with the long-term observations made on old and unrestored graves of the cemetery described in the literature.

An affordable local adsorbent was physically activated and modified to form a novel composite adsorbent. Similar processes were used to activate bentonite and limestone to create this low-cost local adsorbent. Furthermore, when compared to the inexpensive local resources, the innovative composite adsorbent showed improved adsorption capacity. Fouling brought on by sulphate-ion pollution is a significant problem in the wastewater treatment industry. In this work, a composite material known as Limestone and Bentonite composite, was developed, and its capacity to absorb sulphate ions from tainted wastewater was evaluated. Using the scanning electron microscope, X-ray diffraction, Fourier transform infrared spectroscopy, and Brunauer–Emmett–Teller theory, the chemical, elemental, and mineralogical properties, as well as the functional group interaction, of the limestone, bentonite, and LB composite were determined. The model wastewater initially included 900 mg/L of sulphate ions; however, the experiment showed that the new (LB) composite absorbed over 729 mg/L of sulphate ions. Its (LB) = 81% strong elimination effectiveness was observed. It was found that the ideal adsorption conditions were 250 rpm, 60 min, 900 mg/L, and 0.5 g/50 mL. Adsorption studies were carried out in batches. With a greater determination coefficient, the Freundlich model provides a more accurate prediction for adsorption processes, bolstering the theory that chemisorption is the actual adsorption process. These results demonstrate the novel composite adsorbent (LB)’s tremendous potential for sulphate ion absorption.

This study aims to determine the characteristics of hydroxyapatite/SiO2/gelatin composites to fulfil the bone scaffold standards. XRF analysis showed that limestone has a high CaO content of 92.89%, allowing it be used for hydroxyapatite synthesis. The wet precipitation method was used to synthesize hydroxyapatite; meanwhile, the freeze-drying method was used to synthesize the hydroxyapatite/SiO2/gelatin scaffold. FTIR analysis confirmed the characteristic peaks, which indicated the presence of compounds of hydroxyapatite (OH- and PO43-), SiO2 (Si-OH and Si-O-Si), and gelatin (N-H, C-H, and C=O). XRD analysis showed 98.1% hydroxyapatite phase and 1.9% SiO2 phase and SEM analysis showed a scaffold pore size of 155-218?m, optimal for cell attachment. Furthermore, mechanical testing resulted in a compressive strength of 1.71 MPa and porosity testing resulted in a porosity of 75%. This characterization showed the potential use of hydroxyapatite/SiO2/gelatin composites as bone scaffolds. This research can enable further development of scaffold materials in the field of tissue engineering.

The study aimed to investigate the effect of using eggshell waste or eggshell extract as organic calcium source in feed on the physiological conditions and intestines of broilers. A total of 392 one-day-old chicks were randomly distributed into four groups (10 birds each group), CONT (control diet con taining 1% limestone as an inorganic calcium source), EGFL (feed containing 1% eggshell powder as an organic calcium source), EEG1 (feed containing 1% eggshell extracted with Averrhoa bilimbi L. fruit filtrate as an organic calcium source), and EEG05 (feed containing 0.5% eggshell extracted using A. bilimbi L. fruit filtrate). Body weight and feed intake were recorded weekly, whereas blood, intesti nal content, and small intestinal segments were collected at day 35. Our results showed that during days 8-35, weight gain and feed consumption were lower (P0.05) of treatments on coliform and lactic acid bacteria in the ileum and caecum, jejunal crypt depth tended (P=0.09) to be lower in EEG1 and EEG05 than in CONT and EGFL broilers. Con clusively, using 1% eggshell powder or eggshell extract in feed as the substitute for limestone had no detrimental effect on broiler chickens’ growth, physiological status and intestinal condition. Hence, eggshell powder or eggshell extracted with A. bilimbi L. fruit filtrate can be used as an organic calcium source to replace limestone.

There is a lot of evidence that people used stone in the construction of buildings, as well as for other purposes in the municipality of Livno throughout history, as evidenced by numerous archaeological finds. Ever since the Bronze and Iron Ages, and through the Roman, medieval and Turkish periods, stone has been the main building material in these regions. In recent times, two dimension stone quarries have been opened on the territory of the municipality of Livno, one in the locality of Pogledala, east of the city, and the other in the locality of Kik, located between the Kamešnica and Dinara mountains. Both quarries were opened in massive limestones of Upper Cretaceous age. High-quality limestone with the commercial name "Silit light" is being exploited at the Pogledala quarry, and at the Kik site exploitation has been interrupted, but there is a great possibility of its continuation.

Soil correction and fertilization are important in the formation of pastures, but many producers neglect them or use ineffective alternatives. Slow-release fertilizers may harm the establishment of forage plants, as this is a crucial moment during the pasture formation stage. The objective was to evaluate establishment fertilization strategies on the morphogenic, structural characteristics and productivity of Xaraés grass (Urochloa brizantha cv. Xaraés). To this end, two experimental trials were conducted in a greenhouse, both under a completely randomized design. In the first, three establishment fertilization strategies were tested (strategy 1: without lime/NPK; strategy 2: lime + NPK; strategy 3: natural reactive phosphate), with six replications. In the second, a 3 × 10 factorial scheme was used, corresponding to the three establishment fertilization strategies and 10 evaluation dates (32, 39, 46, 53, 60, 67, 74, 81, 88, and 95 days) after emergence. of plants (DAE). In experiment 1 the morphogenic characteristics of the plant were evaluated, in the second the structure and dry mass production of the aerial part and roots of Xaraés grass were evaluated Higher (P

ABSTRACT: Three experiments were conducted to determine effect of feeding 5 commercial limestones varying in solubility (88–97%), mean particle size (500–700 microns), and geographical origin on Ca bioavailability and digestibility in commercial broiler and crossbred chickens. In Experiment 1, both crossbred and commercial chickens were used to measure the effect of dietary Ca level on tibia bone ash to develop a slope-ratio Ca bioavailability assay. Chickens were fed diets that contained Ca levels ranging from 0.20% to 0.95% from 9 to 22 d-of-age. Regressions of bone ash (mg/tibia and %) on supplemental Ca intake yielded large linear responses in both types of chickens in Experiment 1. In Experiment 2, relative bioavailability of Ca in 5 limestones using bone ash as primary response criterion was determined. Thirteen diets were fed to commercial Ross 308 male broilers which were either a Ca-deficient diet (0.30% Ca) or that diet supplemented 0.15 or 0.30% Ca from either reagent grade calcium carbonate (RCaCO3) or 1 of the 5 commercial limestones from 9 to 22 d-of-age. Bioavailability of Ca in limestones relative to RCaCO3 was determined using multiple linear regression of bone ash (mg/tibia and %) on supplemental Ca intake, which yielded slope-ratio relative Ca bioavailability values ranging from 90% to 106% in Experiment 2. In Experiment 3, apparent ileal digestibility (AID) and apparent total tract retention (TTR) of Ca in broiler chickens was measured for the 5 limestones using corn-based diets. The AID and TTR of Ca at 21 d-of-age were low and variable with a range of 20 to 34% for AID of Ca and 12 to 31% for TTR of Ca. Results from these studies indicate that a slope-ratio bone ash assay with either crossbred or modern commercial chickens can be used to measure relative bioavailability of Ca in limestones and there were few consistent differences in relative Ca bioavailability, AID of Ca, and TTR of Ca among 5 commercial limestones evaluated herein.

ABSTRACT: Dietary phytate P (PP) concentration impacts Ca and P digestibility in broilers. Research was conducted to determine the impact of increasing concentration of dietary PP, with and without phytase, on broiler standardized ileal digestibility (SID) of Ca and P. Digestible (Dig) Ca and P were calculated by multiplying SID and the analyzed dietary Ca and P concentrations. The experiment was a factorial arrangement of 2 phytase (0 and 1,000 U/kg) and 4 PP (0.16, 0.23, 0.29, and 0.34%) concentrations. Treatments were fed for 36 h from 20 to 22 d of age (4 b/pen, n ≥ 7 replicate pens/treatment). Different ratios of corn and corn germ were used to achieve the desired PP concentrations. A limestone with 800 µm geometric mean diameter was used as the sole Ca source to achieve 0.7% Ca in the final diets (96% Ca from limestone). An additional diet was fed that was N, Ca- and P-free, for the determination of endogenous losses of each nutrient. Distal ileal digesta were pooled from all birds in a pen. There were no interactions between PP and phytase on SID Ca or Dig Ca from limestone. Irrespective of phytase inclusion, increasing PP from 0.16 to 0.34% decreased SID Ca from 53.8 to 38.1% (P < 0.05). The SID Ca averaged 41.5 and 51.4% in diets containing 0 and 1000 U phytase/kg, respectively, across all PP concentrations (P < 0.05). Interactions were seen between PP and phytase on SID and Dig P (P < 0.05) with SID P of 31.1, 24.0, 20.1, and 16.3% for broilers fed 0.16, 0.23, 0.29, and 0.34% PP diets without phytase, respectively. When phytase was included at 1000 U/kg, SID P was 89.9, 87.5, 73.9 and 60.4% for diets containing 0.16, 0.23, 0.29 and 0.34% PP, respectively (P < 0.05). Overall, phytase improved SID Ca and P independent of PP concentration. However, with increasing PP concentration, both SID Ca and P were negatively affected.

This study investigated the potential of calcined clays from Nigerian deposits in the production of ternary blends of cement. Clay samples were obtained from three different locations namely: Ikpeshi, Okpilla and Uzebba. The raw clay samples were then calcined at 700°C and 800°C. Chemical and mineralogical compositions were determined for the raw and calcined clay samples using XRF and XRD respectively. The chemical composition confirmed these clays as potential pozzolans with SiO2, Al2O3, and Fe2O3 collectively exceeding 70%. XRD analysis identified kaolinite and quartz as major mineral phases in the raw clays, which transformed into metakaolin upon calcination. Compressive strength tests on mortar samples prepared with 50% substitution of Portland cement with the calcined clay and limestone, showed that Ikpeshi clay at 800°C had the best strength performance, with a strength activity index of 0.92 at 28 days, demonstrating superior pozzolanic potential. Strength development was more significant between 7 and 28 days, indicating the pozzolanic reaction's contribution to long-term strength. However, the initial strength at 3 days was lower than the reference cement due to a delayed pozzolanic reaction. XRD analysis of blended pastes revealed typical hydration phases like portlandite, C-S-H, Strätlingite, and ettringite, with the ternary blends showing reduced portlandite content, indicating absorption by the pozzolan's alumina phase. Durability assessments revealed that the ternary blends exhibited improved resistance to water and chloride ion ingress. These findings highlight the effectiveness of Nigerian calcined clays in producing durable and sustainable concrete, supporting their use as supplementary cementitious materials to reduce the environmental impact of concrete production.

Carbonate reservoirs are often stimulated by acidizing and acid fracturing techniques， but the microstructure of the rock surface is corroded and destroyed after acid etching， and the mechanical properties of the rock are changed significantly， which further affects the final stimulation effect. The experiment on the mechanical properties， the study on surface morphological characteristics by scanning electron microscopic （SEM）， and the microscopic pore structure characterization by nuclear magnetic resonance （NMR） are carried out before and after limestone acid etching to clarify the influence of acid etching on the mechanical properties and microscopic pore structure changes of limestone. The results show that acid etching softening layers with a certain thickness of about 11.61 μm appear on the rock surface after acid etching. Remarkably， the compressive strength， elastic modulus， and surface hardness of limestone are all reduced to about 40% before acid etching due to the acid etching softening layers. Dissolved pores of different sizes are formed inside the rock surface after acid etching and stress concentration is induced around the dissolved pores， changing the stress distribution of the acid etching softening layers. Under high closure stress， the dissolved pores are easier to crush deformation or collapse failure， which is also the main reason for the change of mechanical properties of acid etching softening layers. According to the T2 spectrogram of NMR， it is found that there is the largest change in the number of pores with pore sizes between 1 nm and 1 μm， and the acid dissolution alters the internal pore structures of the acid etching softening layers， hence further affecting the mechanical properties of rock after acid etching.

Several perennial snow and ice bodies have been recently studied and monitored in three mountain massifs across the Balkan Peninsula: Prokletije (Northern Albania), Durmitor (Montenegro) and Pirin (Bulgaria), the two glacierets in the Pirin Mountains until soon considered as southernmost of their kind in Europe. In September 2022 a relatively large snow field (about 1.5 ha) was discovered and described for a first time in the glacial cirque Gryka e Kazanit in the Nëmerçka Mountains of Southern Albania. The snow accumulation lies on 1550–1650 m a.s.l. below a vertical limestone cliff with a height of almost 1000 m. The site was visited again in November 2023, when the snow field diminished its size to less than 1 ha. At the same time, multi-annual firn layers were exposed under the last year snow, with depth at least several metres, and indications were observed of ice, buried in the debris cover below. Newest findings indicate that the studied snow-firn body is a glacieret similar to those found in the Pirin Mountains. On a longer-term, nine perennial snow/firm bodies on the Balkans resemble small glaciers rather than snow and ice patches at least under current climatic conditions. Situated on 40°08′ Northern latitude, the newly discovered Nemërçka Glacieret is nominated to be the southernmost glacier in Europe.

Acid Mine Drainage (AMD) is a major environmental problem due to low pH, high sulphate content, and dissolved metals. The aim of this study was to investigate the potential of limestone materials for the primary treatment of AMD water. Different doses of limestone were used in this study in the ratio of 0 g/1,000 mL as control, 20 g/1,000 mL, 40 g/1,000 mL, 60 g/1,000 mL, 80 g/1,000 mL, 100 g/1,000 mL, 200 g/100 mL (limestone/AMD) in a batch experiment of 1,500 mL plastic container. The results showed that the pH of AMD water improved to 8.6 at a dose of 100 g/1,000 mL, and the sulphate concentration decreased from 2,277 mg/L to 506 mg/L at a dose of 200 g/1,000 mL. The removal of Fe, Cu, Zn, Mn, and Ni at 200 g/1,000 mL was 99%, 92%, 68%, 96%, and 99%, respectively. The results of this study also showed that the Mn content decreased slowly as the limestone dosage increased. In addition, this study showed that limestone is a good neutralizing agent for increasing the pH of AMD water and reducing sulphate and dissolved metal concentrations. The results of this study indicated that limestone is suitable as a primary treatment agent for AMD water treatment in gold mines in Tanzania.

This study presents tensile, flexural and water absorption properties of composites made from bio-epoxy resin containing brown eggshell (with membrane), purified brown eggshell (without membrane) and mineral limestone at three filler levels of 5, 10 and 20 wt%. Composites were made by an open silicone mold casting method. Fourier transform infrared (FTIR) spectroscopy was used to demonstrate removal of the membrane. Inductively coupled plasma mass spectrometry (ICP-MS) indicated brown eggshells without membrane had a higher calcium carbonate content suggesting the purification technique worked well. Although composite tensile strengths and flexural strengths were lower than the pure bio-epoxy, the composites containing brown eggshells (with membrane) had slightly better strengths than composites containing purified brown eggshells (without membrane) and mineral limestone for the same particle size of 32 µm. The organic membrane contains proteins on the surface of the eggshells which may be beneficial for chemical bonding to occur with the bio-epoxy resin. Filler contents of 5–10 wt% were acceptable for tensile and flexural strengths. Scanning electron microscopy (SEM) provided visual observations of the fractured surfaces where an increase in surface roughness was related to an increase in filler loading, implying changes occurred within the composite materials. Brown eggshells can be exploited as a waste management opportunity for use as a filler in bio-epoxy composites.

The majority of limestone reservoirs in China are characterized by deep burial， low porosity， and low permeability and are influenced by factors such as elevated temperatures， high closure pressures， and strong heterogeneity. Conventional hydrochloric acid fracturing techniques often fail to achieve non-uniform etching on such reservoirs， resulting in poor transformation effects and hindering the efficient development of such reservoirs. The acid fracturing technology of multi-stage alternating injection was used to facilitate non-uniform etching of fracture wall surfaces by iteratively forming viscous fingering in the prepad. However， the law governing the acid-etching fracturing of multi-stage alternating injection remains unclear， and the acid injection stage boundaries are not determined. At present， acid fracturing design typically relies on empirical approaches. To address these gaps， this study built an acid fracturing model of multi-stage alternating injection for limestone reservoirs by considering the influence of viscosity variation and alternating stages based on a two-scale continuous acidification model. Based on the acid fracturing model of multi-stage alternating injection， the influence of acid viscosity， acid injection rate， and acid injection stages on the acid fracture effects was analyzed by combining the acid rock reaction kinetics， acid-etched fracture experimental data， and numerical simulation results. The acid-etching law of multi-stage alternating injection in limestone reservoirs and the acid injection stage boundaries were determined， and the breakthrough volume of acid fluid was introduced to provide the basis for site optimization. The findings suggest that to enhance the non-uniform etching of fracture wall surfaces and obtain high conductivity of acid-etching fractures， an alternating injection process involving hydrochloric acid and thickened acid should be adopted for pure limestone reservoirs at a formation temperature of 90 °C. 0.4% HPAM-thickened acid should be added when the acid injection rate is 5 m3/min， with an optimal acid injection stage of no more than three. At this time， the breakthrough volume of acid fluid is the smallest， which is suitable for on-site construction.

Abstract Spontaneous water imbibition into matrix blocks can be a significant oil recovery mechanism in fractured reservoirs. Many enhanced oil recovery methods, such as injection of modified salinity brine, are proposed for improving spontaneous imbibition efficacy. Many scaling equations are developed in the literature to predict spontaneous imbibition oil recovery. However, almost none of them included the impact of the diversity in ionic composition of injected and connate brines and the blending/interaction of a low salinity imbibing brine with a higher salinity connate brine. In this research, these two issues are included to propose new scaling equations for the scaling of spontaneous imbibition oil recovery by modified salinity imbibing brines. This study uses experimental data of the spontaneous imbibition of modified salinity brines into oil-saturated rock samples with different lithologies containing an irreducible high salinity connate brine. The collected tests from the literature were performed at high temperatures and on aged altered wettability cores. The results of 110 available spontaneous imbibition laboratory experiments (85, 12 and 13 tests on chalks, dolomites and sandstones, respectively) are gathered. This research initially shows the poor ability of three selected convenient scaling equations from the literature to scale imbibition recovery by modified salinity brine. Then, our newly proposed technique to find the scaling equation for spontaneous imbibition recovery by modified salinity brine, during the abovementioned conditions in limestones (Bassir et al. in J Pet Explor Prod Technol 13(1): 79–99, 2023. https://doi.org/10.1007/s13202-022-01537-7 ) is used in chalks, dolomites and sandstones to develop the three new scaling equations. Finally, a new general equation to scale imbibition recovery by modified salinity brine for all four lithologies is presented. Moreover, for each of the four datasets (chalk, dolomite, sandstone and all the four lithologies), the scaled data by the new equations is matched by two mathematical expressions based on the Aronofsky et al. model and the Fries and Dreyer model. These mathematical expressions can be used to develop transfer functions in reservoir simulators for a more accurate prediction of oil recovery by spontaneous imbibition of modified salinity brine in fractured reservoirs.

Abstract The long-term erosion of rock by solution can induce a series of karst problems. Therefore, this study focused on limestone and conducted dynamic dissolution experiments under deionized water and CO2 solution conditions to study the deterioration mechanism of limestone under nonequilibrium conditions. The results showed that the degree of degradation of the mechanical properties of the samples in a CO2 solution was obviously greater. In a deionized water environment, the degradation of the mechanical properties of the sample is mainly controlled by the physical softening action of the solution. In the CO2 solution environment, the degradation process can be divided into two stages. In the early stage of the experiment (10 days to 20 days), the degradation of mechanical properties of the sample is also controlled by the physical softening action of the solution. With increasing soaking time, the main rock-forming minerals of limestone gradually react with the CO2 solution, the degradation of the sample is controlled mainly by the chemical corrosion of the CO2 solution, and its degradation rate is much greater than that of physical softening. The results can be used as a reference for assessing the long-term stability of underground engineering in limestone karst development areas.

Heritage sites built with natural stone are at risk from fires, which can alter stone properties and compromise its structural integrity. Over 60 studies in the past three decades have examined fire impact on natural stone, providing insights for their prevention and restoration. The primary objectives are to develop effective strategies to mitigate fire risks, protect heritage structures, and ensure the preservation of our cultural legacy. Two noteworthy Portuguese limestones used as heritage building materials: Lioz (LL) and grey Ançã stone (GAS), were studied regarding the effect of high-temperature exposure for simulating fire at 200 °C, 400 °C and 600 °C, followed by cooling in water to reproduce fire extinguish in natural stone buildings. The findings provided insights into how the different temperatures impact the stone morphological, physical and mechanical properties. Color measurements (CIE L*a*b*) showed a color difference from 3 to 32 %; SEM-EDS confirmed microstructure modifications after fire exposure with cracks formation and intragranular porosity development. Among the diverse physical and mechanical properties of the stones, uniaxial compressive strength decreased from 1 to 33 %, Leeb D hardness decreased up to 12.2 %, lowering in open porosity was detected in the range 70–289 % and ultrasound speed propagation were significantly affected after thermal cycle at 600 °C with a negative variation reaching 49 %. Results from TGA show a loss of mass due to retained water (∼40 °C) and loss of hydration water at ∼ 120 °C in both limestones. The total mass loss (∼42–∼44 %) is associated with the loss of H2O, CO2. In conclusion, stones with higher toughness and compression strength exhibited reduced damage at high temperatures due to their enhanced resistance to fracturing under stress. As limestone's mechanical strength decreases under high temperatures, it's advisable to increase its thickness to ensure sufficient support for loads and intended conditions of use. The deficiency of analysis on limestone's mechanical decay from fire reveals a significant knowledge gap regarding the complete extent of damage and deterioration in stone heritage structures.

Rock types with similar lithological components and pore structures form the basic units of porous limestone reservoirs; this influences the reservoir evaluation efficiency and water injection development. As the main oil and gas pay zone in central Iraq, the Cretaceous Khasib Formation reservoirs are influenced by deposition, dissolution, and cementation. There is strong vertical heterogeneity in the most important zone of the Kh2 layer, with diverse rock types and complex pore structures. Based on core observation and casting thin-section identification, the Kh2 layer in the study area was divided into eight lithofacies types as argillaceous bioclastic wackestone, planktic foraminiferium wackestone, lamellar bioclastic wackestone, intraclastic–bioclastic packstone, patchy green algae packstone, green algae and pelletoid packstone, benthic foraminiferium–bioclastic packstone, and intraclastic grainstone. Along with the reservoir void space types of the lithofacies, capillary pressure curves are used to quantitatively analyze the throat and pore features of the different lithofacies. From the porosity–permeability cross-plot characteristics and distribution of pore types, 14 petrophysical facies are obtained. Finally, based on the differences between the lithofacies and petrophysical facies, the Kh2 member is divided into 13 rock types with different geological origins and petrophysical characteristics. Among these, the rock type RT1-8-14 has the best and rock type RT1-1-1 has the worst physical properties among the reservoir rock types. This study provides an optimization method for carbonate reservoir evaluation and is expected to be beneficial for efficient development of similar carbonate reservoirs.

Due to the high embodied carbon of cement and limited availability of conventional supplementary cementitious materials (SCMs), calcined clay has gained numerous attentions worldwide as an alternative SCM. This study explores the potential of four kaolinic clay-rich soils from waste streams in Victoria, Australia, as SCMs. The clays are compared to three commercial calcined clay products from different countries after undergoing grinding and calcination processes. The research assesses physical, chemical, and mineralogical characteristics, as well as pozzolanic activity in ternary cement systems. Results highlight the importance of fineness and calcined kaolinite content in influencing performance. Overall, the study demonstrates the feasibility of Victorian clays as SCM, even from waste streams, with suitable calcination procedures, contributing to sustainable alternatives in cement production.

This paper examines the acid resistance of cement pastes where a portion of the cement clinker is replaced with limestone (LS or calcium carbonate, CaCO3) or ground silica (GS). Specifically, the work is intended to better understand the acid resistance of ASTM C595 IL cement as compared with ASTM C150 cement. The performance of OPC, OPC + GS, and OPC + LS systems were tested in sulfuric acid baths where the pH was held constant at 2.0 and 3.0 using an automated setup that uses titration to add acid. The degradation of the cement paste was measured as a function of time. Thermogravimetric analysis (TGA) was used to quantify changes in the calcium hydroxide (Ca(OH)2) and calcium carbonate (CaCO3) contents of the paste. In addition, the flexural strength of the cement paste specimens was measured. Results indicate that the dissolved sulfate and calcium concentrations due to acidification were not noticeably different for the OPC + GS and OPC + LS mixtures exposed to the same pH. However, as expected, differences were observed between the samples immersed in the solution of pH∼2 and pH∼3 sulfuric acid with the lower pH corresponding to more severe deterioration. TGA results showed that Ca(OH)2 is more susceptible to acid attack than limestone as evidenced by the larger Ca(OH)2 and sulfuric acid consumption in samples immersed at pH∼2. The additional acid consumption that is beyond the consumption of Ca(OH)2 can be explained by the acid attack of other hydration products such as CSH and unreacted cement phases. This results in a significant B3B flexural strength loss for the samples immersed in a pH∼2 as compared to those in the pH∼3 solution. The results demonstrated that the performance of ASTM C595 IL cements was promising and comparable with ASTM C150 cements.

Abstract As the anisotropic behavior of sandstones and limestone along the Khorramabad-Zal expressway has not been studied, this research aims to examine the impact of layer orientation on the strength characteristics and failure patterns of layered sedimentary rocks using the Brazilian test. For this purpose, a total of 8 rock blocks were gathered from Kashkan sandstones and Sarvak limestones in three different locations along the Khorramabad-Zal highway in western Iran. The core specimens were drilled with 54 mm diameter and parallel to the laminations. Overall 150 disc-shaped specimens were subjected to Brazilian tensile strength (BTS) in ten different anisotropy angles, which refers to the angle between the loading direction and the lamination plane. The findings revealed that the highest and lowest BTS values were obtained at β = 70° and 20° for all three types of rock. After analyzing the samples that experienced the Brazilian test and examining their failure patterns, three primary modes of failure were identified: parallel to the lamination (PL), across the lamination (AL), and curved fracture (CF). Furthermore, the transitional angle, which signifies the point at which the dominant pattern of failure shifts from PL to AL or from PL to CF, was also determined.

The present study provides a checklist of land snails collected from Batu Kudik, a small and isolated limestone outcrop in Simunjan, Sarawak. A total of 24 species of land snails, representing 18 genera and 14 families were recorded, including one newly-described subspecies. The most species-rich of the families in Batu Kudik are Diplommatinidae (17%) and Chronidae (17%) with four recorded species from each of the families. Based on our analysis, Plectostoma wallacei kudikense subsp. nov., Opisthostoma javanica and Georissa pyrrhoderma were identified as the most abundant land snails at this isolated outcrop, whereas Diplommatina onyx and Everettia minuta were recorded as the least abundant. All of the land snails at Batu Kudik were exclusively found sheltered between limestone boulders, underscoring the critical role of this outcrop as their refuge for survival. Consequently, conserving this biodiversity-rich limestone area becomes paramount to prevent the local extinction of these land snail species and possibly other organisms that depend on the unique attributes of the limestone for their survival. We also provide detailed descriptions of Plectostoma wallacei kudikense, a new subspecies of the genus Plectostoma which is endemic to Batu Kudik.A description of a new subspecies Plectostoma wallacei kudikense subsp. nov.

In the paper, changes of pH value during 20 days of soil interaction with the solution have been traced. Differences in the reaction rate using ameliorants of different chemical nature for liming have been established. It was revealed that the ameliorative effect of using materials of silicate nature in the experiment was lower than that of carbonate nature. According to the effect all ameliorants used in the experiment can be arranged in the following descending order: dolomite flour (DF), crushed stone sieve (CSS) > conversion chalk (CC), dolomitized limestone flour (DLF) > blast furnace slag (BFS) > oil shale ash (OSA). For all lime fertilizers empirical models of pHKCL value change over the whole experimental interval were developed. Clustering of separate variants of the experiment, produced by different ameliorants on their influence on the index rNKCL on the whole interval of study was carried out.

The article shows changes in certain mechanical properties of polyvinyl chloride (PVC) depending on the quality of added limestone as a filler. Natural limestone and limestone hydrophobicized with stearic acid were added. Modification experiments were carried out with "wet" and "dry" processes in order to find out the required amount of stearic acid for a complete surface coating of limestone-degree of coating 99.90%. Coating of the limestone surface was achieved in the "wet" process with 1.5% stearic acid, while in the "dry" process the same degree of coating was achieved with 3% stearic acid. A significant amount of both "wet" and "dry" modified limestone was prepared. Such a product was added to PVC mixture in order to investigate mechanical properties of the obtained PVC product. Research into the mechanical properties of PVC has shown that PVC containing limestone modified by the "wet" process exhibits better mechanical properties than that containing limestone modified by the "dry" process. For example, PVC obtained from a mixture containing limestone modified by the "wet" process with 1.5% stearic acid shows a better tensile strength of 54.20 MPa, while limestone modified by the "dry" process with 3% stearic acid shows a tensile strength 53.20 MPa.

Chemical Enhanced Oil Recovery (CEOR) methods are garnering significant global attention in light of the substantial decline in available oil resources. These techniques are employed to enhance oil recovery from various types of reservoirs by influencing critical parameters, such as the mobility of trapped oil within the reservoir rock's pore network, interfacial tension (IFT) between water and oil, wettability and the spreading behaviour of chemical solutions on rock surfaces. Nanoparticles (NPs) represent novel agents in CEOR processes, offering promising contributions owing to their enhanced surface activity at the crude oil-brine-rock interface and their impact on disjoining pressure. Incorporating polymers into nanofluids improves the dispersion stability of NPs, extending their capability for wettability alteration and achieving faster equilibrium states compared to polymer-free nanofluids. Experimental investigations involved the use of various combinations of tragacanth, TiO2, and Al2O3 with water at different temperatures for oil recovery. The results revealed that the tragacanth + Al2O3 combination at 50°C exhibited the highest recovery rate of 16.57%. The most significant decrease in interfacial tension was observed at 25°C (16.75%), while the most favourable characteristics for reducing interfacial tension (9.38%) were observed at 50°C compared to 75°C (18.3%). Tragacanth demonstrated the highest viscosity among the tested substances at 25°C, with a measured value of 4.27 centipoise (cP), while reductions of 2.87 cP and 1.45 cP were observed at 50°C and 75°C, respectively. According to the obtained results, it is appropriate to say that the solution of tragacanth + Al2O3 has shown the best performance in increasing EOR and decreasing the interfacial tension in sand-pack flooding.

نشر مجموعة متنوعة من الكتل الحجرية المنقوشة من اكتشافات عين شمس بمخزن آثار عرب الحصن بالمطرية [AR] يتناول هذا البحث دراسة ونشر مجموعة متنوعة من الكتل الحجرية مستطيلة الشكل والمكتشفة أثناء أعمال الحفائر بمنطقة آثار المطرية وعين شمس، وهى محفوظة حالياً بمخزن آثار عرب الحصن بالمطرية، وهذه الكتل عبارة عن بقايا عناصر معمارية هامة تعود لفترات زمنية مختلفة. وترجع أهمية هذه التحف الحجرية أنها أجزاء من مبانٍ أثرية تم هدمهما في العصور القديمة، وبدراسة هذه الكتل التي ظلت منسية لسنوات عديدة بعد اكتشافها، ستعطي لنا صورة أوضح عما كانت عليه هليوبوليس قديماً، ومن الممكن أن يتم ربطها بتحف أثرية أخري مكمله لها. وجميع الكتل الحجرية محل الدراسة من الحجر الجيري وعليها نقوش وكتابات هيروغليفية أغلبها في حالة سيئة، الكتلة الحجرية الأولي رقم 147 عليها خرطوش باسم الملك أمنحتب الثالث من الأسرة الثامنة عشر. وتحتوي على اسم الإله آمون-رع وألقابه، والكتلة الحجرية الثانية رقم 167 تحتوي على اسم الإله بتاح وألقابه، والكتلة الحجرية الثالثة رقم 177 صنفت على أنها بقايا عتب مدخل باب وعليها بقايا نص لألقاب حور البحدتي، والقطعة الرابعة رقم 456 وهي عبارة عن جزأين تحتوي على اسم الإله أوزير وألقابه. [EN] This research seeks to study and publish various rectangular stone blocks discovered during excavations in al-Mataria and ʿAin-Shams areas, currently preserved in the Arab al-Hīṣn Antiquities Store in El-Mataria. These blocks from demolished buildings in ancient times hold remains of important architectural elements dating back to different periods. Studying these forgotten blocks after many years of their discovery will give a clearer picture of what Heliopolis was in the past, and its possible link to other complementing artifacts. All the studied stone blocks are made of limestone with Hieroglyphic inscriptions and writings, most of which are in poor condition: block Nº.147 contains a cartouche of «Amenhotep» III from the eighteenth dynasty and the name of the god «Amun-Ra» with his titles; block No.167 contains the name and titles of the god «Ptah»; block Nº.177 is considered the remains of a lintel situated at the door's entrance. It contains traces of text that depict the titles of «Horus Behdetite». The block Nº.456 is comprised of two parts and bears the name of the deity «Osiris» and his titles.

Hydroxyapatite (HAp) is the main inorganic component that forms teeth and bones. The abundant limestone reservoir in Indonesia can be utilized as a natural resource for the green synthesis of hydroxyapatite. The objective of synthesizing Fe-doped hydroxyapatite/ZnO nanocomposites is to enhance the magnetic properties of hydroxyapatite, facilitating its utilization as a biomaterial in drug delivery systems. This application proves valuable in regulating the timing and location of active substance decay in pharmaceuticals. The coprecipitation method was employed to synthesize Fe-doped hydroxyapatite (Fe-HAp) at varying concentrations of 0%, 2.5%, 5%, and 10% mol. Subsequently, Fe- HAp/ZnO nanocomposites were crafted with a weight ratio 4:1 through straightforward homogenization between nano Fe-HAp and nano ZnO, utilizing ethanol as a solvent. The analytical tools employed for characterization included X-ray fluorescence (XRF), X-ray diffraction (XRD), and Vibrating Sample Magnetometer (VSM). XRF analysis revealed that the Ca/P ratio in the Fe- HAp/ZnO nanocomposite decreased with increasing Fe dopant concentration, while the weight percentage of ZnO remained consistent across all nanocomposites. The XRD results demonstrated the presence of typical diffraction patterns of HAp and ZnO in the Fe-HAp/ZnO nanocomposite. However, secondary phases such as β-TCP, CaCO3, and Fe2O3 were observed in the Fe-HAp sample. The crystallite size of the Fe-HAp/ZnO nanocomposite generated in this study ranged from 29 to 38 nm. VSM characterization outcomes indicated that the substitution of Fe(III) can modify the diamagnetic properties of hydroxyapatite, rendering it ferromagnetic or superparamagnetic, depending on the dopant concentration employed.

Vertical orthogonal joints are a common feature in shallow crustal rocks. There are several competing theories for their formation despite the ubiquity. We examined the exceptional exposures of orthogonal joints in flat-lying Ordovician limestone beds from the Havre-Saint-Pierre Region in Quebec, Canada (north shore of Saint-Lawrence River) to test conceptual models of joint formation in a natural setting. In the region, the spacing of cross-joints is consistently larger than the spacing of systematic joints by a factor of 1.5 approximately. The joint-spacing-to-bed-thickness ratios (s/t) are much larger in these beds (s/t = 4.3 for systematic joints, and 6.4 for cross-joints) than those in higher strained strata along the south shore of the Saint-Lawrence River (s/t = 1), highlighting the effect of tectonic strain in decreasing fracture spacing and block size. The high values of s/t indicate that cross-joint formation was unlikely caused by a switch from compression to tension once a critical s/t ratio for systematic joints was reached (as hypothesized in previous studies). We proposed a new model for the formation of orthogonal joint systems where the principal stress axes locally switch during the formation of systematic fractures. The presence of ladder-shaped orthogonal joints suggests a state of effective stress with σ1∗≫0 > σ2∗>σ3∗ and where σ2∗-σ3∗ is within the range of fracture strength variability at the time of fracture. This research provides a new mechanical model for the formation of orthogonal joint systems and cuboidal blocks.

The recent global warming started at the end of the 19th century, causing an increase in the average temperature of Earth and posing environmental, social, economic, and cultural repercussions. Much tangible cultural heritage is composed of natural stones, which decay due to the combination of chemical, physical, and biological factors. Biodeterioration leads to a loss of the performance requirements and socio-economic value of stone building materials. In the future, the dynamics of biodeterioration will hypothetically vary. This study aims to shed light on this variation by comparing biodeterioration under historical climatic conditions (1995–2014) with a future scenario defined by the IPCC SSP5-8.5 for the reference period 2080–2099. The material tested is Pedra de Ançã (PA), a candidate for World Heritage Stone. Climatic chambers were used to simulate the historical and predicted environmental conditions. The scope of this investigation is to understand the growth dynamic of the biodeteriogen Rhodotorula sp. and to study the morphological and aesthetic variations of stone surfaces. Biochemical and micro-topographic analyses highlighted the metabolic activity of the population proliferating under distinct environmental conditions, revealing better adaptability of Rhodotorula sp. and higher biocorrosion in the historical climate status with respect to the future.

he escalating carbon dioxide (CO2) emissions have precipitated climate change, underscoring the urgent need for innovative solutions. Carbon Capture and Storage (CCS) represents a groundbreaking technology to mitigate carbon emissions by capturing CO2 and depositing it deep within reservoirs. This study focuses on the storage aspect of CCS by scrutinising reservoir properties. A pivotal factor influencing the geological storage of CO2 is the wettability of the rock/CO2/brine system, which is intricately linked to the contact angle. However, previous research has indicated that pH can significantly influence the wettability of this system. Acetic acid, a prevalent organic acid in the petroleum industry, is commonly encountered and serves as a means to modulate pH. This experiment investigates pH variations, ranging from 3 to 7, through the introduction of acetic acid, while maintaining a salinity level of 30,000 ppm. Additionally, the type of rock mineral plays a crucial role in these findings. Therefore, this paper emphasises carbonate rocks, with a particular focus on limestone composed primarily of calcium carbonate (CaCO3). The experiment is conducted under elevated supercritical conditions, encompassing pressures of 10 MPa and 15 MPa, along with temperatures of 305 K and 323 K. Equilibrium contact angles are determined by measuring receding and advancing angles using the Vinci IFT 700 instrument under supercritical conditions. The results reveal a consistent trend wherein contact angles decrease as pH, temperature, and pressure increase, indicating a shift towards a water-wet system at higher pH, temperature, and pressure levels.

Additives added to the flexible pavement mixture aim to increase the strength of the pavement. Limestone which is a sedimentary rock consists of the mineral calcium carbonate (calcite) or the double carbonate of calcium and magnesium (dolomite). The use of limestone in pavement mixtures is expected to increase the performance of Marshall parameters. This study aims to determine the suitability of limestone as a filler for 3 types of pavement mixtures, namely Asphalt Concrete Wearing Course, Hot Rolled Sheet and Split Mastic Asphalt. In this study, the limestone used was sourced from Jorong Durian, Nagari Kamang Mudiak, Kamang Magek District, Agam Regency, West Sumatra Province. The tests were carried out using following variations of limestone; 0%, 25%, 50%, 75%, 100% of the total amount of filler in the mixture. The results of the study using limestone as filler obtained at an optimum content of 29% for AC-WC, 22% for HRS, and 82.5% for SMA. In addition, AC-WC pavement was found to the best increase in Marshall stability performance. Therefore, it can be concluded that limestone from Kamang Mudiak is most suitable to be added to AC-WC pavement mixtures.

Abstract The use of nondestructive techniques in the technological control of concrete allows to evaluate and monitor the condition of the material without interfering with its properties; therefore, it is highly desirable in on-site inspections. Among these techniques, ultrasonic testing stands out as one of the most promising by its speed and simplicity to obtain results. However, inferences of strength and stiffness properties using ultrasound parameters should be made with caution, since many factors may interfere with wave propagation. This research aimed to evaluate the behavior of parameters obtained by ultrasonic testing (velocity of wave propagation [V] and stiffness coefficient [C = density × V2]) as predictors of the strength (fc) and stiffness (Eci) of concrete produced with coarse aggregates from different mineralogical origins. To achieve the objective, 128 specimens were produced with four aggregate mineralogical origins and four water-cement ratios, with 8 replications each. The ultrasonic tests were performed with two-frequency transducers (45 and 80 kHz). Prediction models of fc and Eci were statistically significant (P-value 91,2%) and with fc (R2 > 82%) than the model using only [V]. General regression models (regardless of the gravel type) were also statistically significant (P-value 79% and prediction errors higher than those obtained for the specific models for different rock types.

Due to numerous leakage zones, such as vugs, fractures, and caves appearing in carbonate rocks, lost circulation, the main issue, restricts safe and effective drilling. The lost circulation pattern of the vug-fractured limestone formation has been extensively studied using the Mishrif formation of the H oilfield in the Middle East as the research sample. The equivalent physical models of three different types of leakage zones, including vug, natural fracture, and induced fracture, were built based on the interpretation of FMI (Formation MicroScanner Image) logging. By embedding discrete fractures into a variable permeability matrix and solving it using the finite element method (FEM), a three-dimensional fluid–solid coupling mathematical model of mud loss rate was established. The study focused on the effects of drilling fluid performance parameters on lost circulation as well as the parameters of the single leakage zone (vug, natural fracture, or induced fracture) on lost circulation. Additionally mentioned were the variable characteristics of mud loss rate and cumulative mud loss volume in various combined ways of leakage zones. The findings indicate that there are considerable differences in how various types of leakage zones affect lost circulation properties. Fractures, particularly induced fractures, can result in more severe lost circulation than those brought on by vug for the creation of a single leaking zone. Mud loss rate and cumulative mud loss volume are greatly influenced by fracture width and dissolved radius, both of which have thresholds. Due to the enhanced flow conductivity, the lost circulation is more severe the more complicated the leakage zone combination mode is. The numerical model developed in this research provides a new perspective on how to analyze the lost circulation pattern of vug-fractured limestone formations and provides theoretical direction for lost circulation control of drilling in this kind of formation.

The resilient modulus (MR) and the backcalculated modulus from the FWD testing (EFWD) of the unbound layers are critical inputs in the analysis/design of pavements. Several studies have tried to develop a conversion factor between these two parameters, while the nonlinear stress dependency of unbound materials and the pavement strain response are mostly missing from the literature. This study aims to compare the laboratory-measured MR of recycled aggregate base (RAB) materials and a virgin aggregate base using field-based EFWD and tries to establish pavement’s responses to loading using vertical strains from both the MR and EFWD values of the respective materials as comparability parameters between the two. For this purpose, a control virgin aggregate (VA, limestone) and three types of RAB materials were selected to construct four test sections. The test sections were modeled in layered elastic- and finite-element-based pavement response models to calculate the vertical strains at the mid-depth of the base and top of the subgrade layers. A comparison of the lab-calculated vertical strains using MR with actual vertical strains in the field from EFWD showed that there was no relationship between the two stiffness parameters in all tested RABs. The vertical strains, based on the lab MR, undermined the stiffness of the recycled aggregates in the field. In contrast, the values of EFWD based on the vertical strains remained close to the MR strains of limestone (VA) throughout the testing period, establishing an EFWD vs. MR relationship (MR = 0.87 EFWD). The results also show that fine RCA was a better-performing material over three years. This research not only explores how the hydration process in RABs limits the development of MR-EFWD correlations but also underscores the need to consider real-world conditions when assessing their performance.

Limestone calcined clay cement (LC3) presents a promising alternative material due to its reduced CO2 emissions and superior mechanical properties compared to traditional Portland cement (PC). This study investigates the synergistic effect of calcined coal-series kaolinite (CCK) and limestone (LS) on the hydration behavior of cement, specifically focusing on varying mass ratios. The combination of CCK and LS promotes the formation of strätlingite and carboaluminates, which enhances early-age strength development. Additionally, the inclusion of CCK facilitates the formation of carboaluminates during later stages of hydration. After 56 days of hydration, the content of carboaluminates is over 10%wt. This stimulation of secondary hydration products significantly refines the evolution of pore structure, with the harmful large pores gradually transformed into harmless medium pores and gel pores, leading to marked improvements in compressive strength from 7 to 28 days. Replacing 45% PC with CCK and LS at mass ratio of 7 to 2, the compressive strength of blends reaches 47.2 MPa at 28 days. Overall, the synergistic interaction between CCK and LS presents unique opportunities to minimize the CO2 footprint of the cement industry without compromising early and long-term performance.

In this study, the feasibility of using ceramic wastes in the production of blended cement was evaluated by substituting limestone with ceramic waste at the percentages of 5, 10, 15, 20, and 28% before the milling stage. The chemical, physical, and mechanical properties of the cements were determined according to relevant standards, and the results were compared. The chemical analysis showed that the SiO2 content of the cements increased with higher ceramic waste substitution percentages, while the CaCO3 content decreased. The grindability of cements decreased with increased ceramic waste ratios, slightly reducing the Blaine specific surface area values. The water consistency for the cements was set at 28%, and all the cements met the standard limitations. The spread diameters for all types of cements were similar and practically usable in terms of workability. The cements containing ceramic waste either maintained or extended the setting time. All cements with ceramic waste exhibited higher flexural and compressive strength compared to the reference cement. The highest flexural strengths were achieved with a 28% ceramic waste substitution ratio across all curing ages. Regarding compressive strengths, all cements exhibited higher compressive strength than 10 MPa at 2 days and 32.5 MPa at 28 days, classifying them as 32.5 R-type blended cements. When the medium- (56–90 days) and long-term (365 days) compressive strengths were compared, the highest strength values were obtained from the cement with a 28% ceramic waste substitution. Although limestone-blended cement is emerging as a promising alternative to traditional Portland cement, these types of cement still contribute to environmental degradation due to the extraction of natural limestone resources through quarrying. This study showed that blended cements can be produced using ceramic waste, providing a more sustainable and environmentally friendly solution for the construction industry.

The present study investigated the distribution of elements and potentially toxic elements (PTEs) in soil profiles in the southeastern region of Nigeria, where unrefined and primitive mining practices are common. Soil samples were collected from mine and non-mine sites in Ameka and Nkalagu and analyzed for total elemental concentration using portable X-ray fluorescence (pXRF). The results showed that the Ameka mine-affected soils were heavily polluted, while the Ameka non-mine-affected soils were moderately polluted. The Nkalagu mine and non-mine-affected soils were also moderately polluted. The potential ecological risk (PER) was high in the Ameka mine-affected site due to elevated As, Cu, and Pb levels, while the Ameka non-mine-affected site had a low PER. The enrichment factor (EF) values indicated more enrichment of PTEs in the mine-affected sites compared to the non-mine-affected sites. The geoaccumulation index (Igeo) showed moderate to extreme contamination in the Ameka mine-affected site with Cu, Zn, As, and Pb. In contrast, the Nkalagu mine-affected site had considerably lower contamination. The regression model showed that site characteristics alone were insufficient to explain elements and PTEs distribution, emphasizing the importance of considering soil properties in understanding their spatial patterns. The study highlights the higher concentrations of As, Cu, and Pb in the mine-affected sites compared to the non-mine areas and recommends remediation strategies for these elements and PTEs, especially in the vicinity of mine sites. Further laboratory analysis is recommended to understand the mobility of PTEs with depth for better remediation approaches.

The thermal conductivity of natural monoliths of calcite, dolomite marble, and limestone from various deposits was measured using the absolute stationary method of longitudinal heat flow in the temperature range of 50–300 K and the dynamic method in the range of 323–573 K. A majority of calcite marbles were inferior in thermal conductivity to dolomite marbles. At room temperature, the thermal conductivity coefficients of all studied samples were lower k = 5 W/(m K). The obtained data were compared with the literature data. The diversity of experimental data from different authors on the thermal conductivity of carbonates is associated with qualitative differences in the samples studied

This study involved an investigation to assess the performance of limestone sorbent for spray dry scrubbing of sulphur dioxide from simulated flue gas using a lab-scale spray dryer. The project comprised of detailed experimental testing utilizing Central Composite Design (CCD) to investigate the influence of spray drying parameters on the removal of SO2 from flue gas. Several experiments were performed to analyse the influence of stoichiometric ratio (0.5 - 2.5), flue gas flowrate (24 - 36 m3/h), and inlet gas temperature (120 - 200 ℃) on SO2 removal efficiency of limestone. A predictive quadratic model was established based on experimental findings to correlate independent variables and the response. The model exhibited a strong fit to the data, indicated by R-squared coefficient of 0.98. The experimental findings revealed that the stoichiometric ratio (SR) had a large impact on the removal efficiency of SO2 in the spray dryer while the flue gas flowrate through the scrubber exhibited minimal influence. The combined effects of the spray drying variables were found to significantly impact the removal efficiency. A high removal efficiency of 70% was achieved when employing a higher stoichiometric ratio (SR=2) and lower temperature (T=140 °C). The lowest removal efficiency was recorded at a high temperature (T=180 °C) coupled with lower stoichiometric ratio (SR=1). The characterization of the dry collected products revealed evidence of desulphurization, manifesting in the formation of hannebachite (Ca2SO3.2H2O) and unreacted sorbent.

The tomb of Cyrus the Great, founder of the Persian Empire, is considered one of the most important monuments of Iran. Its advanced state of deterioration motivated the need to carry out a study focused on analyzing the possible damage caused by the presence of soluble salts, and to assess the suitability of an electrokinetic treatment for their extraction. Preliminary diagnostics carried out on stone samples taken from the tomb confirmed that it is affected by the action of soluble salts, and especially by the presence of nitrates and sulfates. The effectiveness and possible harmful effects caused by electrokinetic treatment were evaluated, under laboratory conditions, using the same limestone that makes up the tomb. The obtained results show that this treatment, in a short period of time, reduces the ionic content, reaching high percentages of anion extraction, without causing any damage, which indicates that it is suitable for this type of stone.

This paper offers an overview of methods for assessing geological risks in the development of domestic deposits of carbonate rocks and an example of calculation for one of the deposits of the Kherson region. Conducting geological exploration at each stage of deposit development is accompanied by certain risks, which by their characteristics belong to geological and investment risks, which together make up the group of risks of the mining business. The purpose of determining geological and economic risks when carrying out geological exploration works is to take into account those negative characteristics of the subsoil area, which can objectively reduce the quantity or affect the quality of the mineral. The listed methods of taking risks into account are possible for use at the final stages of geological and economic assessment during detailed exploration of deposits. Geological risk is defined as the probability of not confirming the quantitative and qualitative characteristics of the deposit's reserves. The degree of uncertainty is quantified through the coefficient of variation of resources. For relatively well-studied objects, it is small – 0-0.2, for medium-studied ones – 0.1-0.4, for poorly studied ones – from 0.3 to 1 and more. Intervals of values overlap because they depend on the complexity of the geological structure of the object. According to the results of calculations, the assessed area has low risks of quality loss, which is ensured by the even distribution of the useful component. Fluctuations in the contents of SiO₂ and MgCO₃ can have negative consequences, because for this deposit the increased amounts of mass for SiO₂ + Al₂O₃ if we evaluate the raw material as flux. By lithological varieties, the greatest risks of non-confirmation of quality were recorded for oolite limestones and pelitomorphic shell limestones.

Salt crystallization is a particularly relevant issue in the conservation of limestones used in Cultural Heritage sites. In this study, various facies of limestones were characterized through porosimetric and mechanical tests. The samples were subjected to experiments to determine their resistance to salt crystallization by verifying the number of cycles at which 50% of them began to lose weight. This number of experimental cycles was compared with the result calculated by the analytical procedure of a chemomechanical model found in the literature. The comparison showed a significant capability of the model to predict the experimental data.

The feasibility of using crushed limestone instead of sand in cement grout is examined in this work. This study entails performing several tests, including the Brazilian test, the compressive strength test, and the stress–strain correlation test. The curing times used were 7, 14, and 28 days for mixtures with various proportions of cement to limestone (1:1, 1:2, and 1:4). The conventional sand–cement grout laboratory tests were prepared using a similar methodology to examine the effectiveness of the suggested substitute. The findings show that the limestone-based grout has sufficient strength, but that it is less than that of the typical sand material. The values of the tensile strength and elastic modulus were determined. A focus was made on the tensile strength and stress–strain relationship. A special laboratory set-up was used to look at the progress of failure using strain gauges fitted to the cylindrical samples both vertically and horizontally. The angular shape of the particles’ ability to interlock is responsible for the material’s increase in strength. According to this study, crushed limestone can be used as a substitute for sand in circumstances where sand supply is constrained. The suggested grout can be used in the shotcrete of tunnels and rock surfaces.

Cadmium (Cd) contamination in agricultural soils has emerged as a significant concern, particularly due to its potential impact on plant-based food. Soil pH reductions can exacerbate Cd mobility, leading to excessive accumulation in crops. While liming has been demonstrated as an effective method to mitigate Cd accumulation in rice grains in acid soils of southern China, its efficacy in remediating acid soils in northern China remains unclear. In this study, a multi-year field experiment was conducted on farmland impacted by zinc ore smelting at coordinates of 33.92° N 112.46° E to investigate the use of limestone for controlling Cd accumulation in wheat and maize grains. The results indicated that applying 7.5 t ha−1 of limestone significantly raised the soil pH from 4.5 to 6.8 as anticipated. Different rates of limestone application (2.25, 4.45, and 7.50 t ha−1) reduced Cd bioavailability in the soil by 20–54%, and Cd accumulation in wheat grains by 5–38% and maize grains by 21–63%, without yield penalty. The remediation effects were sustained for at least 27 months, highlighting limestone as a promising ameliorant for smelting-affected farmland in northern China.

The use of mineral reinforcements in polymer matrix composites has emerged as an alternative for sustainable production, reducing waste and enhancing the physical and mechanical properties of these materials. This study investigated the impact of the melt flow index (MFI) of HDPE and the particle size of two mineral reinforcements, Bahia Beige (BB) and Rio Grande do Norte Limestone (CRN), on the composites. All composites were processed via extrusion, followed by injection, with the addition of 30 wt.% reinforcement. Chemical analyses revealed similar compositions with high CaO content for both minerals, while X-ray diffraction (XRD) identified predominantly calcite, dolomite, and quartz phases. Variations in the MFI, reinforcement type, and particle size showed a minimal influence on composite properties, supported by robust statistical analyses that found no significant differences between groups. Morphological analysis indicated that composites with lower MFI exhibited less porous structures, whereas larger particles of BB and CRN formed clusters, affecting impact resistance, which was attributed to poor interfacial adhesion.