Bituminous Material Research Articles

Predicting the properties of bitumen using machine learning models trained with force field atom types and molecular dynamics simulations

This study enhances the molecular analysis of bitumen by transitioning from traditional chemical descriptors, such as SARA (Saturates, Aromatics, Resins, and Asphaltenes) fractions and elemental compositions, to specific force field atom types in Molecular Dynamics (MD) models. This shift improves the precision in predicting material properties critical for bituminous material characterization. Machine Learning Models (MLMs) were developed to use these atom types as input features, inherently reflecting fundamental chemical characteristics. Trained on data from over 1,770 LAMMPS simulations of diverse bitumen types and conditions, these MLMs enable the prediction of properties like density, heat capacity, solubility parameters, and thermal expansion coefficients without the need for additional MD simulations. The models utilize 30 chemical descriptors corresponding to specific atom types in the PCFF force field, which collectively account for over 95% of the influence on these properties. By accurately predicting fundamental, thermodynamic, and kinetic properties, the use of MLMs and force field atom types allows researchers to efficiently tweak the chemical nature of organic molecules and mixtures to achieve desired properties. With near-instantaneous prediction times, these MLMs offer valuable insights for advancing bitumen research in the construction and petroleum industries, reducing the need for more intensive simulation techniques.

One-Dimensional Electrical Resistivity Prospecting for Small Dam Projects: A case Study Smaquli Dam, East Erbil City, Kurdistan Region of Iraq

Abstract: This study employs the One-Dimensional Vertical Electrical Resistivity technique to elucidate the subsurface stratigraphy and structures beneath the axis and abutments of the suggested Smaquli dam, situated to the east of Erbil City in Kurdistan Region of Iraq (KRI). Three traverses were conducted using a Schlumberger array. Data interpretation was performed using the Russian commercial software, IPI2WIN. Each measurement point featured a maximum total electrode spread ranging from 400-600m, reaching an investigation depth of 130m to 150m. The inter-distance between successive measurement points varied from 16m to 17.5m. Geo-electrical sections were generated by interpreting the data, revealing three distinct lithological groups: alluvial deposits (upper first group) with a thickness ranging from 3 to 10 meters, marl and marly limestone of the Shiranish Formation (second group) with thickness ranging from 18 up to 110 meters, and dolomitic limestone of the Bekhme Formation (third group) which its thickness is not defined. These lithological groups exhibited significant resistivity contrasts, rendering the resistivity method effective for delineating their interfaces. The resistivity of the upper horizon ranged from 18 to 136 Ω·m, the second horizon exhibited values between 19 and 304 Ω·m, while the lower third horizon showed high resistivity values ranging from 97 to over 50000 Ω.m.. The relatively low resistivity values of the lower horizon (Bekhme Formation) are interpreted as fractured and water-saturated limestones, whereas the high values are indicative of bituminous material. A correlation was established between the geo-electrical sections and borehole geologic columns, demonstrating consistency in indicating the presence of two rock units within the uppermost 20m, which corresponds to the borehole depth.

Influence of Waste Rubber Nano-Material Utilization on The Engineering Properties of Asphalt Matrix

Abstract The highway pavement construction industry is widely recognized as the most suitable establishment for recycling waste materials. Consequently, selecting sustainable materials constitutes a crucial concept for developing an innovative pavement construction characteristic. This research investigation aims to explore the consequences of utilizing waste rubber nanomaterial as a sustainable supplementary at four various weight ratios (0.5, 1, 1.5, and 2) in bituminous material. The assessment involved physical features such as viscosity, ductility, penetration, penetration index, and softening point. A dry mixing process is also accomplished for modified asphalts by conducting a high shear mixer at 5000 rpm for 30 minutes at 160 °C was chosen to ensure optimal dispersion of the waste rubber nanomaterial. Overall, the results demonstrated that adding waste rubber nanomaterial increased viscosity and softening point temperature but decreased ductility and penetration. The enhanced penetration index values of the modified asphalts result from the incorporation of residual rubber nanomaterial. In contrast, the binder modified with 2% residual rubber nanomaterial and nano-rubberization exhibited a greater penetration index (PI); thus, it positively impacts the resistance to rutting failure.

Performance and Morphology of Waterborne Polyurethane Asphalt in the Vicinity of Phase Inversion.

Waterborne polyurethane asphalt emulsion (WPUA) is an environmentally friendly bituminous material, whose performance is highly dependent on the phase structure of the continuous phase. In this paper, WPUAs in the vicinity of phase inversion were prepared using waterborne polyurethane (WPU) and asphalt emulsion. The chemical structures, thermal stability, dynamic mechanical properties, phase-separated morphology and mechanical performance of WPUAs were studied. Fourier-transform infrared (FTIR) spectra revealed that there are no -NCO bonds in either the pure WPU or WPUAs. Moreover, the preparation of WPUA is a physical process. The addition of WPU weakens the thermal stability of asphalt emulsion. WPU improves the storage modulus of asphalt emulsion at lower and higher temperatures. The glass transition temperatures of the WPUA films are higher than that of the pure WPU film. When the WPU concentration increases from 30 wt% to 40 wt%, phase inversion occurs; that is, the continuous phase shifts from asphalt to WPU. The WPUA films have lower tensile strength and toughness than the pure WPU film. However, the elongations at break of the WPUA films are higher than that of the pure WPU film. Both the tensile strength and toughness of the WPUA films increase with the WPU concentration. Due to the occurrence of phase inversion, the elongation at break, tensile strength and toughness of the WPUA film containing 30 wt% WPU are increased by 29%, 250% and 369%, respectively, compared to the film with 40 wt% WPU.

Performance evaluation of flexible pavement using polyethylene terephthalate (PET)

In this study, the benefits and feasibility of incorporating Polyethylene Terephthalate (PET) into Flexible pavement were evaluated. The study aims to identify new ideas on recycling plastic wastes and thereby improving overall sustainability. The Samples were prepared by adding PET with an increasing concentration level along with optimum asphalt content with a percentage by weight of 3.5%, 4.0%, 4.5%, 5.0%, 5.5% and 6%. Multiple tests were conducted on Natural aggregates including Resistance to degradation of aggregates by Abrasion and Impact, Specific Gravity and Abrasion of coarse aggregates, and Impact Value of Aggregates. Similarly, the tests conducted on asphalt include the specific gravity of semi-solid bituminous material, the ductility of bituminous material, the flash point and softening point of asphalt, and the penetration grade of bituminous material. Rutting potential of the optimum asphalt, Plastic mix Was evaluated by increasing the frequency of load cycles from 0 to 5000 cycles. Furthermore, the effect of asphalt and plastic content on the density, Flow, voids, and stability were also analysed. It was found that the addition of PET resulted in improved stability by more than 50% specifically 52%, while 70% improvement was observed in flow characteristics of Hot Mix Asphalt. However, a slight change in density was observed. The sample also showed a reduction in rut depth by more than 40% of the mix.

Insights into organic matter source and depositional environments of shales from the Ponta Grossa Formation in Parana basin, Brazil

Marine transgression events and plant species' evolution to terrestrial environments increased the amount of organic matter in sediments during the Devonian Period. Subsequently, a bituminous material known as shale was formed, containing organic compounds that enable the reconstruction of environmental conditions from previous eras. These rock formation events are recorded worldwide, however, in the Ponta Grossa Formation, southern Brazil, a deeper understanding of samples from the Devonian Period is necessary. The goal of this study was to understand the regional environmental conditions, the origin of the organic matter, and the degree of maturation of the bituminous material. Shale samples were collected from an outcrop on the eastern border of the Paraná Basin and processed in the laboratory to obtain the saturated hydrocarbons fraction posteriorly analyzed. The results indicate a poorly oxygenated environment, with various salinity levels, mixed organic sources, and a high thermal maturity of the samples. The analysis of compound hydrocarbons elucidates the environmental conditions during the Devonian Period in the Ponta Grossa Formation, providing inferences applicable to the stratigraphic interval represented by this record and within the domain of the sampled area.

Influence of Thermoplastic Polyurethane on the Properties of Asphalt Cement and the Elastic Behavior of Asphalt Mixtures

The useful life of pavements determines the design of asphalt mixtures. However, premature structural failures and low durability are one of the main problems in pavement engineering today. The action of loads produced by traffic, exposure to environmental factors and the inadequacy of conventional designs of asphalt pavements are some of the main problems associated with the durability of the pavement. The modification of asphalt binders is an alternative that has been used for some years to improve the properties of bituminous material. Among the modifying materials are elastomers, a class of polymers with elastic properties that can be heat-treated. In this study, the asphalt was modified by wet means by adding 5, 10 and 15% of Thermoplastic Polyurethane (TPU) by weight of the binder. Subsequently, standard samples were prepared with the characterized constituents and mixtures with the modified asphalt cement. Consequently, tests were carried out to obtain the optimal mixture that improves the properties of conventional pavement. The results show that the optimal TPU addition content is 5%. With this percentage, the modified binder presented a greater elastic recovery of up to 5.60% and a reduction of up to 42.6% in penetration compared to conventional asphalt. In addition, using the Marshall method, it was determined that the stability of the modified mixtures was much higher than that of standard mixtures for light, medium and heavy traffic; so, they will have a higher resistance to deformation and better fatigue behavior.

Effect of Crumb Rubber Modified Bitumen in Hot Mix Asphalt Concrete

Improving bituminous material using recycling waste (Crumb rubber) as modifier was emphasized in this paper. Crumb rubber (CR) waste was added by volume to the bitumen in 0, 5, and 7 %. The volumetric properties tests were conducted using the Marshall Test (ASTM D1559), others includes Characterization of Binder and Aggregate materials in HMA, (FTIR Analysis), Fundamental mechanical properties tests, also Rheological properties according with ASTM D7369-11, Dynamic Modulus Test, according with AASHTO R83-17, Rutting Test according with AASHTO T324-04, Fatigue Cracking Evaluation according with AASHTO TP124 and Flexural Beam Fatigue Beam Test according with AASHTO T 321-07. The result indicates that crumb rubber is very suitable as a modifier, with bitumen of 60/70 PEN grade. From the results, at the designed production temperature 135oC for unmodified 60/70 Bitumen, the modified admixed samples (0% and 5% CR) at the same binder content show a high void percentage for mixes (5% CR). This is an indication that the modified asphalt mixtures exhibited volumetric properties with higher voids and lower density due to change in viscosity caused by modification and requires compaction at higher temperature to be at par with regular unmodified bitumen grade. However, the air voids of mixtures fall within the specification range of 3% to 5%, and as such acceptable for use as a modifier in 60/70 PEN grade bitumen.

Effects of different inhibitors on emission characteristics, environmental impact and health risk of volatile organic compounds from asphalt binder

Volatile organic compounds (VOCs) of asphalt will cause adverse environmental impact and workers’ health risk, inhibitors can be used to reduce the emission of VOCs from asphalt. Three inhibitors, including activated carbon (AC), expanded graphite (EG) and hydrotalcite (MA), were used to modified asphalt in this work. The effects of inhibitors on the VOCs emission characteristics of asphalt were investigated at multiple levels of VOCs total concentration, groups distribution and components characteristics. 101 asphalt VOCs components were detected, among which alkane accounted for more than 50% of the total concentration, followed by aldehyde and benzene. AC with the largest specific surface area and pore capacity exhibited the best inhibitory effect on the emission of VOCs with total concentration inhibition rate of 45.58%, followed by MA, while excessive MA would have adverse effect. Over 90% of VOCs components emissions had been suppressed by AC and EG. And inhibitors had the best inhibitory effect on the emission of olefin and aldehyde in VOCs, followed by ketone, but had the worst inhibitory effect on alkane, which was due to the weak interactions between non-polar alkane and polar hydroxyl on the surface of inhibitors. Furthermore, the effects of different inhibitors on the environmental impact and health risk of VOCs from asphalt were also systematically studied. The highest total inhibition rate of OFP and SOAP from asphalt VOCs by AC was only 58.3% and 21.7%, which was ascribed to the limited suppression on OFP and SOAP generated by alkane and benzene. Meanwhile, the non-carcinogenic risk from asphalt VOCs was mainly caused by acrolein with a contribution rate of 80.0%, AC and EG can completely inhibit the emission of acrolein in asphalt VOCs, while MA showed the poor performance. The contribution rate of acetaldehyde to the carcinogenic risk of asphalt VOCs reached 93.7%, while inhibitors had limited inhibitory effects on its emissions. This study contributes to a deeper understanding of the correlation mechanism between inhibitors, emission reduction characteristics of asphalt VOCs and environmental-health benefits, which could provide theoretical support for the design of bituminous material with low environmental-health load.

Analysis of redox-sensitive trace elements to the reconstruction of the depositional paleoenvironment of the Ponta Grossa Formation in southern Brazil

In the Devonian period, several intense climatic changes occurred on Earth, such as global cooling and intense volcanic eruption events, increasing the amount of organic matter in water bodies and forming a bituminous sedimentary material containing redox-sensitive trace elements, called shale. Among the places with this type of rock formation from the Devonian period, one of them is the Ponta Grossa region, located in the Paraná Basin, southern Brazil, which lacks studies that use metals to understand the depositional environment of its formation. Therefore, this study aims to analyze the redox-sensitive trace elements together with the total organic carbon to understand the depositional environment at the time of the formation of these shales. For this, outcrop samples were collected and analyzed regarding the total organic carbon and the redox-sensitive trace elements, generating ratios between them. From the results obtained, it was observed that the environment was warmer and humid, with very low salinity, a greater tendency to anoxia, periods of greater primary productivity, and marine transgressions. Thus, it was possible to know the depositional environment of organic matter that later originated the shale deposits in this region of the planet.

Diagnosis of the use of environmental strategies for the rehabilitation and maintenance of roads with recycled bituminous material –MBR in the city of Bogotá

The research is carried out in order to give a diagnosis for the use and rehabilitation and maintenance strategies of the road network in the city of Bogotá, providing a sustainable environmental initiative through recycled materials resulting from the asphalt layer removed from the demolition for the maintenance of the roads and from which MBR (recycled bituminous material) is obtained, which through a production process is transformed and mixed with other products, becoming an environmentally friendly alternative and the final product is used for rehabilitation and maintenance of rural roads within the city.

Modeling of Fatigue Cracking in Asphalt Materials Based on the Paris Law with an Initialization Term—Calibration from Notched and Unnotched Specimens

Abstract This article aims at presenting a thermo-mechanical model dedicated to fatigue cracking in bituminous material. The model calibration based on two-point bending (2PB) fatigue tests performed on specimens of bitumen-bound sand is also detailed. In the model, crack growth is handled by the Paris law considering the initialization term Nini. This parameter represents the number of loading cycles required to initiate a short macrocrack of length a0 from which the Paris law can be applied. The tests utilized for calibration and comparison with the numerical simulations are performed on notched and unnotched trapezoidal samples, for different levels of imposed displacement amplitude. The parameters of the Paris law are determined using the notched specimens (a0 being assimilated to the notch depth) except for Nini, which is deduced from the difference in lifetime duration between the tests carried out on notched and unnotched specimens. The full calibration procedure described thereafter has the advantage to not depend on the choice of a0. It is shown that the simulations run for the calibrated model are globally in good agreement with the test results obtained for both types of samples and for all the imposed displacement amplitudes. Finally, the model is used to predict the response of four-point bending tests carried out on the same bitumen-bound sand, considering the input parameters determined from the 2PB tests. The intrinsic nature of the model is evaluated through its ability to simulate both types of tests using the same set of material parameters.

An Investigation into the Behavior of Disposable Face Masks in Modified Bitumen for Sustainable Transportation Pathways

Since December 2019, COVID-19 infection rates have risen considerably, and the virus is currently widespread around the world. Following the COVID-19 outbreak, the production of medical waste has skyrocketed. Disposable face masks are considered medical waste. Alternative measures must be implemented to assist in reducing medical waste disposal, which can result in serious public health problems and have a negative influence on the environment. In this regard, this research was conducted to investigate the effect of disposable face mask (DFM) ash with varied rates ranging from 5% to 20% by weight on bitumen with a 5% increment to be utilised as an alternative material in asphalt pavement. A series of physical and rheological tests were conducted on the bitumen samples to study the behavior of the DFM ash in bituminous material. Overall, the physical and rheological test results revealed that introducing 20% DFM ash to the modified bitumen was unable to achieve the same properties as with the conventional SMA14 asphalt binder. However, the modified bitumen penetration grade PEN 60/70 has improved the properties and quality of the asphalt in the flexible pavement. In addition, utilising the DFM waste in road construction would be a sustainable technique for protecting the environment by minimising face mask waste caused by the COVID-19 epidemic while lowering the pavement’s construction cost. These research findings may be commercialised to generate revenue in the construction industry for sustainable transportation pathways.

Evaluation of Crack Development Through a Bituminous Interface Reinforced With Geosynthetic Materials by Using a Novel Approach

Using interlayers made of geosynthetic materials has proved its effectiveness with respect to postponing the appearance of reflective cracking on the surface. In this regard, in a reinforced bituminous interface, the crack first propagates from its origin upward until it reaches the interlayer. When the interlayer has higher stiffness than its surrounding bituminous material, the crack path diverts horizontally along the interlayer plane until the whole energy of the crack dissipates. Nevertheless, this mechanical improvement needs to be further studied to quantify the reinforcement effects of geosynthetic materials in mechanistic-based design of reinforced sections. This study aimed to develop a laboratory test method that not only is able to illuminate the crack resistance effect of geosynthetics but is also able to differentiate the load–displacement curves among different types of reinforced bituminous interfaces. The results led to the advent of a new test device called the crack widening device in which reproducibility and statistical variability of the outcomes were all within the acceptable range. On this ground, using paving fabric showed superior performance among others with respect to energy dissipation capability and retarding the loss in the stiffness modulus during the crack propagation stage compared with the corresponding unreinforced cases. On the other hand, using the reinforcement grids led to a higher initial stiffness of the reinforced structure, especially when embedded between coarse hot mixtures.

Recycling of polymer modified bituminous mixes with reclaimed asphalt pavement – An experimental study

Recycling is an attempt to effectively utilize the used material to manufacture new material of acceptable or if possible superior quality materials. Recycling promotes resource preservation, energy efficiency, and cost-effectiveness in manufacturing. Recycling can be effectively applied for bituminous pavements. The scarified bituminous material from the surface course can be mixed with fresh aggregates and/or fresh binder to relay new pavements performing the same function as in the original application. Thus scarified bituminous material, which is milled from asphalt surface is recycled in hot mix asphalt. Hot mix recycling has shown to be an effective method due to its low cost and capacity to produce mix of a high calibre. Thus, reclaimed asphalt pavement recycling is necessary for use for technical, economical, and environmental reasons. The purpose of the study is to assess the effectiveness of hot asphalt mixtures using recycled asphalt pavement (RAP). Bituminous material that had been scarified was obtained for the current investigation from a national highway in Belagavi, India. It was discovered that the project location has a BC-II and PMB-40 gradation. The site-recycled material underwent a bitumen extraction test to determine its gradation and binder concentration. In the current laboratory experiment, four different sorts of mixes were created and put to the test. New bituminous mixes were made using the BC-II gradation. Two mixes were proportioned, and recycled materials were used to partially replace the coarse and fine aggregates in the BC-II mix, respectively. The mixes were produced using the Marshall approach and the MS-2 criterion. The mixes were investigated in terms of their Marshall properties, moisture susceptibility through ITS & TSR tests. The recycled mix when combined with fresh aggregates and binder to compensate for loss in gradation and ageing of binder respectively results in a mix of properties similar and even better than fresh bituminous mix.

ДОСЛІДЖЕННЯ ВПЛИВУ НАПОВНЮВАЧІВ РІЗНОГО ПОХОДЖЕННЯ НА ВЛАСТИВОСТІ АСФАЛЬТОБЕТОНІВ

Introduction. The properties of a bituminous material are determined by the peculiarities of the bonds that arise between individual mineral grains and depend on the properties of bitumen, the thickness of the bitumen layer covering the mineral grains, as well as on the processes of interaction between mineral materials and bitumen on their common interface. To ensure a strong and stable bond between the grains, bitumen should evenly cover the surface of the mineral materials with a thin layer. To increase the strength of the pavement constructed from bituminous material, it is necessary that the maximum amount of bitumen is adsorbed by the mineral material, and the content of free bitumen is reduced to a minimum value. Problem Ыtatement. Depending on the nature of the mineral material and the chemical composition of the bitumen, the properties of its thin layers change in different ways. The strength of bitumen in a thin layer on an active mineral surface increases with decreasing thickness, while on an inactive surface the strength of bitumen changes little with decreasing layer thickness. Objective. The present study was devoted to determining the effect of aggregates of different origins on the volumetric properties of asphalt concrete and the mechanical properties of asphalt concrete, as well as on their weather resistance. Materials and methods. Mineral filler from limestone, granite, quartzite, and fly ash was used for the study. Results. The results of the research showed that the type of aggregate has virtually no effect on changes in the volumetric and mechanical properties of asphalt concrete. However, at the same time, asphalt concrete with different aggregates differs significantly in water and frost resistance.

Experimental Study of the Effect of Tack Coats on Interlayer Bond Strength of Pavement

The performance and lifetime of the flexible asphalt pavement are mainly dependent on the interfacial bond strength between layer courses. To enhance the bond between layers, adhesive materials, such as tack coats, are used. The tack coat itself is a bituminous material, which is applied on an existing relatively non-absorbent surface to ensure a strong bond between the old and newly paved layer. The primary objective of this study was to evaluate the effects of various types of tack coat materials on interlayer bond strength and to determine the optimal application rate for each type. The tack coat types used in this paper were RC-70, RC-250, and CSS-1h. Both laboratory-prepared and field-constructed hot mix asphalt concrete pavements using the tack coats were tested for the binding strength between the layers. A direct shear test was used for the testing. The results obtained from the study showed that the optimum application rate for RC-70 was 0.1 L/m2, and for RC-250, it was 0.2 L/m2, while the optimum application rate for CSS-1h was 0.1 L/m2. From the field test, the optimum application rate of the RC-250 tack coat was 0.1 L/m2.

Production of Bitumen Modified with Low-Molecular Organic Compounds from Petroleum Residues. 7. Study of the Structure of Formaldehyde Modified Tars

Three samples of bituminous material with different softening temperatures of 321, 332, and 356.4 K were obtained by the method of chemical modification of tar with formaldehyde using sulfuric acid as a catalyst. The determination of the group hydrocarbon composition was carried out for the raw materials of the modification process (tar) and the resulting bitumens. An FTIR study of the obtained groups of hydrocarbons (oil, resins, and asphaltenes) was also carried out. The structural transfor¬mations were investigated and a possible chemistry of the tar modification process with formaldehyde was proposed.

Sedimentological and petrophysical heterogeneities controls on reservoir characterization of the Upper Triassic shallow marine carbonate Kurra Chine Formation, Northern Iraq: Integration of outcrop and subsurface data

The lack of knowledge about the relationship between carbonate sedimentary facies and pore system modifiers in northwestern and northern Iraq severely restricts carbonate oil exploration in these areas. This research aims to highlight the significance and influence of sedimentological and petrophysical heterogeneity and their impact on reservoir characterization of the Kurra Chine Formation, which have been studied in oil wells at Ain Zalah (AZ-29), Butmah (Bm-15), and Kand (K-1), in addition to the Sararu outcrop in northern Iraq. In this study, integrated methods that incorporate thin section petrography, well logs, statistical techniques and core analysis were used for the investigation. The study revealed that the Kurra Chine Formation in the studied sections mainly consists of limestone, dolomite, shale, and anhydrite, the last of which is absent in the Sararu outcrop. Its thickness in previous outcrop and wells was 848 m, 1136 m, 985 m, and 1149 m for Sararu, AZ-29, Bm-15, and K-1, respectively. Petrographically, five main microfacies types and nine submicrofacies were identified in the Kurra Chine carbonates of the studied sections. The percentages and distribution of these submicrofacies in the study area are diverse and show their heterogeneity. Diagenetic processes like micritization, dolomitization, cementation, neomorphism, compaction, stylolitization, solution, pyritization, and silicification resulted in increasing heterogeneity in the formation. They played a significant role in improving or reducing the reservoir characterizations of the formation. Dolomitization and dissolution processes enhance the petrophysical properties of the studied formation, especially the medium-to coarse-grained crystalline idiotopic dolomite. On the other hand, cementation, compaction, and neomorphism reduce the pore volume of the Kurra Chine Formation rocks. Qualitatively, porosity in the Kurra Chine Formation was divided into two main groups: interparticle (intergrain and intercrystal) and vuggy pores. The interparticle pore space is subdivided into three petrophysical classes: Class 1, Class 2, and Class 3. Class 2 represents the most common interparticle porosity type and is very important because it contains bituminous material. Moldic and intragrain pores are the most abundant separate vug pores within formation successions. The touching vug pores are represented by fractures, microfractures, and fenestrals. Quantitatively, three types of porosity have been calculated for the formation using conventional well logs: effective, interparticle, and separated vuggy porosity. The Butmah-15 well reservoir property outperformed the other two wells in terms of reservoir property indicators, particularly in the middle of the studied formation at depths ranging from 3089 to 3399 m. Porosity in this depth interval is interparticle, with values ranging between 0 and 0.35, while permeability values range from zero mD in beds cemented by anhydrite cement to 6196 mD within MF6 in limestone beds that are rich in interparticle and fracture porosity. The AZ-29 and K-1 wells have poor reservoir properties, especially effective porosity and permeability. This research provides a better understanding of the relationship between carbonate sedimentary facies and pore system modifiers of shallow marine environment carbonates, and it can aid in reservoir evaluation for better exploitation of these valuable resources in Iraq and elsewhere in carbonate sedimentary basins.

Metamorphism as the cause of bone alteration in the Jarrow assemblage (Langsettian, Pennsylvanian) of Ireland

AbstractThe Jarrow assemblage is a Lagerstätte of Pennsylvanian tetrapods and fish preserved in the Leinster Coalfield, Ireland. Fossils from this site have an interesting taphonomy that is not observed in other Pennsylvanian coal swamp assemblages. Jarrow tetrapod bone material has undergone alteration and eventual coalification, causing specimens to become poorly defined from the surrounding coal matrix. Bone alteration at Jarrow has traditionally been linked to early diagenesis. A multi‐analytical approach, combining x‐ray scanning electron microscopy, cathodoluminescence, micro computed tomography and laser ablation quadrupole inductively coupled plasma mass spectrometry, was used to investigate the origin of alteration within the Jarrow fossil specimens. Original bone morphology is no longer present, being replaced by bituminous material and sphalerite surrounded by tabular apatite (a morphology atypical of bone apatite). Direct U–Pb dating of this recrystallized apatite provides an age of 302.03 ± 11.38 Ma. In this recrystallized apatite, core‐to‐rim variation in halogen elements, variably positive and negative Eu‐anomalies and depletion in light rare earth elements (REEs) suggest an influence of hydrothermal fluids sourced during the maturation of the Leinster Coalfield. A new taphonomic model for the Jarrow assemblage is proposed: alteration of primary fossil bone occurred primarily due to burial heating of the Leinster Coalfield caused by Variscan deformation. Bone apatite was dissolved and subsequently recrystalized as tabular crystals, probably concurrent with mineralization of sphalerite and during coalification, giving the Jarrow assemblage fossils their unique appearance.