Abstract Microfacies analysis and Paleoenvironment of Baba Formation were investigated in Anah area, Anbar Governorate, Western Iraq. Baba Formation was cropped out in Wadi Al-Khazgah section with 9 ...meters thick, consisting of white to creamy, chalky, coralline, high fracture Limestone. Five Microfacies types were recognized Coral Lime Boundstone, Lepidocyclina Lime Packstone, Nummulitids Lime Packstone, Miliolids Lime Packstone - Grainstone, and Coraline Algae Lime Wackestone described in 10 samples collected from one section (Wadi Al-Khazgah Al-Gharbi section). These Microfacies described on the basis of the presence of the Benthic Large Foraminifera (BLF) as Miliolids, Lepidocyclinide, Rotalide and skeletal fragments of brachiopod, coral, and algae shell. The paleoenvironment of Baba Formation was determined fore-Reef and Reef environments.
87Sr/86Sr-derived mean ages from low-Mg calcite Kuphus incrassatus and Ostrea haitensis bivalves provide an updated and refined chronostratigraphy for selected Oligocene-Miocene carbonate and ...siliciclastic units in Puerto Rico and the Dominican Republic. Results indicate ages of middle to late Oligocene for the San Sebastian Formation (ca. 29.78–26.51 Ma), the Lares Limestone (ca. 26.51–24.73 Ma), and the Montebello Member (ca. 27.30–24.10 Ma); middle Miocene to the early part of the late Miocene for the Cibao Formation (ca. 12.17 Ma), the Aguada (Los Puertos) Limestone (ca. 14.67–11.14 Ma), and the Aymamón Limestone (ca. 10.98 Ma) in northern Puerto Rico as well as for the Ponce Limestone (ca. 14.97–9.84 Ma) in southern Puerto Rico and the Yanigua–Los Haitises Formations (ca. 15.75–12.58 Ma) in northeastern Dominican Republic; and late Miocene for the Cercado Formation (ca. 6.31–5.88 Ma) in northwestern Dominican Republic. These results show some significant modifications to previous chronostratigraphic studies. The San Sebastian Formation marks the last major input of siliciclastics in Puerto Rico. The Lares Limestone is characterized by a diverse warm- and cool-water coral assemblage, whereas the Montebello Member is characterized by large benthic foraminifera and mollusks, which likely indicates differences in depth of deposition or environments that were differentially influenced by upwelling. The ultimate disappearance of warm-water corals in the late Oligocene coincides with the end of global warming and coral extinction events. The Cibao Formation, the Aguada (Los Puertos) Limestone, the Aymamón Limestone, the Ponce Limestone, and the Yanigua–Los Haitises Formations are predominantly composed of shallow marine deposits consisting of red algae, mollusks, small benthic foraminifera, and cool-water corals in the upper parts. These characteristics are consistent with an upwelling control, which has been documented as a regionally important process in the Caribbean during that time. The reappearance of corals indicates an environmental change that coincides with closure of the Central American Seaway. The closure resulted in circulation changes, warm temperatures, and low nutrients in the Caribbean, which created suitable conditions for diverse coral reef development, as exemplified by the Cercado Formation.
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BFBNIB, DOBA, IZUM, KILJ, NMLJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
In this study, the macro properties (residual compressive strength), meso properties (mesoscopic images), and micro properties (reaction products and pore structures) of paste specimens with various ...limestone and calcined clay contents at elevated temperatures (20, 300, 550, and 900 °C) are experimentally investigated. According to the experimental results, (1) the strengths of all samples increase at 300 °C, while those of the LC3 ternary blended pastes increase more significantly because of the formation of katoite and the further hydration of binders. After the treatments at 550 and 900 °C, the reduction in the strengths of the LC3 samples is greater than that of the plain paste. (2) With further increasing temperature, all samples generate more meso cracks. (3) At 900 °C, a large gehlenite crystalline phase is formed in the samples with calcined clay. In summary, the microscopic explanation for the macroscopic and mesoscopic properties of LC3 paste at elevated temperature is investigated.
•Macro–meso–micro properties of LC3 paste are investigated at elevated temperatures.•At 550 and 900 °C, the LC3 experiences a higher reduction in strength than plain paste.•The addition of calcined clay helps to form katoite, which improves the strength of LC3 at 300 °C.•As the temperature increases, all samples generate more meso cracks.•At 900 °C, gehlenite is formed in paste specimens containing calcined clay.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The hydration process of blended cementitious materials is primarily affected by the effect mechanism of supplementary cementitious materials. This study utilizes electrochemical impedance ...spectroscopy (EIS) method to investigate the hydration kinetics of cementitious materials incorporating metakaolin (MK), quartz (Q) and limestone powder (LS). The experimental results reveal the influence of MK+Q+LS on the hydration kinetics, phase assemblage, and microstructure of the blended systems. Besides, the electrochemical impedance response of blended cement materials exhibits variation based on the MK contents and the curing age. Furthermore, the resistance of the continuously connected micro-pores (Rccp) in the blended cementitious material progressively increases throughout the hydration process. The inclusion of MK reduces the Rccp values at early ages, while contributes to an increase in Rccp values from 7 days onward. Additionally, positive correlations are established between the Rccp value and compressive strength/heat release across different MK contents and curing ages. The combination of Rccp values and other characterization method can effectively reveal the microstructure evolution process. Therefore, as a nondestructive method, EIS can be effectively applied to predict the hydration of cementitious materials and the mechanical properties.
•System with 40 % MK and 60 % quartz, simulated as low-grade calcined clay, exhibit comparable compressive strength to OPC.•The Rccp value, associated with the connected pores, exhibits a correlation with compressive strength and heat release.•Rccp values is related with the filler effect, carboaluminate formation effect and the pozzolanic reaction effect of MK.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Limestone flour is used in a variety of industrial sectors such as power and heat generation, glass-making, paper-making, the construction industry and construction materials manufacturing, the ...production of agriculture, plastics and rubber goods, as well as coal mining, and environmental protection. This paper aims to characterize and interpret the limestone flour supply and demand trends in the main applications in Poland in the last decade. In order to track the changes of domestic consumption for this commodity, its major users have been surveyed along with analyses of data from the Statistics Poland (GUS). The results showed that during 2009–2018 the coal-fired power plants became the biggest customer of limestone flour utilized as a sorbent in the wet flue gas desulfurization method (FGD). This method has been implemented in the vast majority of Polish power plants. It is estimated that in the last decade the total annual production capacity of limestone flour at the milling plants in Poland increased by 1.5 million tons, to around 6.0 million tons. In the forthcoming years, this is expected to continue to increase despite EU restrictions on fossil fuel use (especially hard coal and lignite). Other promising areas of future growth are: for limestone flour of medium quality—the construction materials manufacturing and the construction industry itself, for limestone flour of the highest quality—the glass industry, while for fine-grained limestone flour of high-quality—the plastics and rubber industries. In terms of resource security, it is worth noting that Poland is a country rich in limestone deposits. However, only some of them, that is, limestone rock varieties of the Jurassic and Devonian ages from the Kielce vicinity in central Poland are suitable for the production of high-quality limestone flour for the needs of the mentioned industries. The paper analyses the potential of the limestone flour production from the available limestone rock deposits with respect to the current and future needs of the domestic market in Poland.
In mountainous areas, freezing is a prominent phenomenon for weathering processes in rock walls. A freezing front penetrates rock crack networks and causes its propagation. To study the evolution of ...rock mass stability, a suitable model of stress generated by freezing in open rock cracks is needed. This stress evaluated by the simple volume expansion model in a closed crack is too high to be realistic. In this paper, we present an assessment method for this stress and some results. Different experiments on notched limestone specimens submitted to freeze–thaw cycles were performed. Three different tight limestones (Larrys, Chamesson, Pierre de Lens) were tested. Actually, the stress generated by freezing begins to grow at the top of the notch where an ice plug is created and makes it possible for higher stresses to develop in deeper parts of the notch. Consequently, the stress induced by freezing depends on the geometry of the open crack represented by the notch. This value is, however, limited by the permeability of the surrounding rock matrix. A model of the stress evolution generated by freezing along an open crack was established and its envelope curve, named maximum stress, was parameterized. This maximum stress generated by freezing along the crack is completely defined by knowledge of the pore network of the limestone matrix and the geometry of the crack.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
This paper reports the composition and properties of highly flowable self-consolidating concrete (SCC) mixtures made of high proportions of cement replacement materials such as fly ash and pulverized ...limestone instead of high dosage of a plasticizing agent or viscosity-modifying chemical admixtures. Self-consolidating concrete mixtures are being increasingly used for the construction of highly reinforced complex concrete elements and for massive concrete structures such as dams and thick foundation. In this study, by varying the proportion of portland cement (OPC), Class F-fly ash (F), and limestone powder (L), SCC mixtures with different strength values were produced, and the properties of both fresh and hardened concrete were determined. For a comprehensive analysis and quantification of emissions and global warming potential (GWP) from concrete production, life-cycle assessment (LCA) was employed. We find that high volume, up to 55% by weight replacement of OPC with F, or F and L produces highly workable concrete that has high 28-day and 365-day strength, and extremely high to very high resistance to chloride penetration along with low GWP for concrete production.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UM, UPCLJ, UPUK
The paper analyzes the petrophysical and mechanical properties of two porous limestones that were used in the construction and restoration works at the castle of Chambord in France, a UNESCO World ...Heritage site. The original construction material, the tuffeau limestone with a total porosity of 45±0.6%, and the replacement stone of later restorations, the Richemont limestone with a total porosity of 29±0.7% were subjected to freeze–thaw tests under laboratory conditions to evaluate the role of critical degree of saturation and pore-size distribution in frost damage. Laboratory tests were coupled with in situ measurements of temperature and relative humidity at stone surface at the castle of Chambord. In situ data show that the stones in the castle experienced several freezing–thawing cycles annually. The limestone samples under laboratory conditions were subjected to up to 50 freeze–thaw cycles under eight different degrees of saturations. The total porosity, tensile strength, ultrasonic pulse velocity, the mercury intrusion porosimetry and scanning electron microscopy techniques were employed to analyze the conditions of samples during the cycles. The experimental results show that when the degree of saturation of the two studied limestones exceeds 80–85%, the freeze–thaw, damage occurs even after a few freeze–thaw cycles. The effect of freezing is very fast if the water saturation is sufficient. Moreover, results indicate that these stones have the same critical degree of saturation of about 85%, despite the differences in porosity. Finally, the results indicate that the increase in the number of freezing–thawing cycles has no effect on the critical degree of saturation, but the frost damage is mostly controlled by pore-size distribution rather than by total porosity. Accordingly, critical degree of saturation can be defined as an intrinsic stone property.
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•Microclimatic and frost data of limestones of Chambord castle, France were analyzed.•In laboratory, limestone samples were saturated at various degrees of saturation.•Petrophysical and mechanical properties were studied after 50 freeze–thaw cycles.•Freeze–thaw cycles applied has lower influence on frost damage than supposed.•Critical degree of saturation of limestone controls the frost damage.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
•Higher NS and NC replacement amounts lead to lower flowability of UHPC matrix.•There are optimal contents of NS and NC for UHPC matrix to obtain highest strengths.•The improvement in mechanical ...strengths incorporating NS and NC become higher with lower W/B ratio.•Compared to standard curing, NS and NC can accelerate cement hydration more effectively by combined curing.
The effects of nano-silica/SiO2 (NS) and nano-limestone/CaCO3 (NC) on the flowability, strengths and microstructure of ultra-high-performance concrete (UHPC) matrix under different curing conditions were investigated in this study. The NS and NC were incorporated at different ratios as partial mass replacements for cement. On the microstructure aspect, the results verify that the NS acts as an effective filling material, which reduced porous areas and accelerated the cement hydration process by pozzolanic effect. On the other hand, the NC acts mainly as an inert filler material that created a denser microstructure, but accelerated the cement hydration process through boundary nucleation growth effect. On the mechanical properties aspect, a threshold value of the NS and NC contents were found so that the compressive, flexural strengths and flexural to compressive strength ratio of the UHPC matrix were found to increase as the NS and NC contents increased towards the threshold content, and then to decrease with the increase of NS and NC contents when the threshold was surpassed. Corresponding to the highest measured mechanical strengths of UHPC matrix, the optimal contents of NS and NC are around 1.0% and 3.0%, respectively. The research concluded that the NS and NC contents are critical to the performance of UHPC matrix.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
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