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Geochemistry and depositional environment of fuchsite quartzites from Sargur Group,western Dharwar Craton,India
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作者 C.S.Sindhuja G.Harshitha +1 位作者 C.Manikyamba K.S.V.Subramanyam 《Acta Geochimica》 EI CAS CSCD 2024年第3期555-570,共16页
Meso-Neoarchean fuchsite quartzites are present in different stratigraphic positions of Dharwar Craton including the oldest(~3.3 Ga)Sargur Group of western Dharwar Craton.The present study deals with the petro-graphic... Meso-Neoarchean fuchsite quartzites are present in different stratigraphic positions of Dharwar Craton including the oldest(~3.3 Ga)Sargur Group of western Dharwar Craton.The present study deals with the petro-graphic and geochemical characteristics of the fuchsite quartzites from the Ghattihosahalli belt to evaluate their genesis,depositional setting and the enigma involved in the ancient sedimentation history.Their major mineral assemblages include quartz,fuchsite,and feldspars along with accessory kyanite and rutile.The geochemical com-positions are characterized by high SiO_(2),Al_(2)O_(3),low MgO,CaO,strongly enriched Cr(1326–6899 ppm),Ba(1165–3653 ppm),Sr(46–210 ppm),V(107–868 ppm)and Zn(11–158 ppm)contents compared to the upper continental crust(UCC).The UCC normalized rare earth element(REE)patterns are characterized by depleted light REE[(La/Sm)UCC=0.33–0.95]compared to heavy REE[(Gd/Yb)_(UCC)=0.42–1.65]with conspicuous positive Eu-anomalies(Eu/Eu^(*)=1.35–18.27)characteristic of hydrothermal solutions evidenced through the interlayered barites.The overall major and trace element systematics reflect a combined mafic-felsic provenance and suggest their deposition at a passive continental margin environ-ment.The comprehensivefield,petrographic,and geo-chemical studies indicate that these quartzites are infiltrated by Cr-richfluids released during high-grade metamorphism of associated ultramafic rocks.The Sargur and the subse-quent Dharwar orogeny amalgamated diverse lithounits from different tectonic settings,possibly leading to the release of Cr-richfluids and the formation of fuchsite quartzite during or after the orogeny.Thesefindings sug-gest a pre-existing stable crust prior to the Sargur Group and the link between orogenic events and various mineral deposits in the Dharwar Craton. 展开更多
关键词 Dharwar Craton Ghattihosahalli Fuchsite quartzite PROVENANCE Depositional setting
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An Investigation into the Compressive Strength,Permeability and Microstructure of Quartzite-Rock-Sand Mortar
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作者 Wei Chen Wuwen Liu Yue Liang 《Fluid Dynamics & Materials Processing》 EI 2024年第4期859-872,共14页
River sand is an essential component used as a fine aggregate in mortar and concrete.Due to unrestrained exploitation,river sand resources are gradually being exhausted.This requires alternative solutions.This study d... River sand is an essential component used as a fine aggregate in mortar and concrete.Due to unrestrained exploitation,river sand resources are gradually being exhausted.This requires alternative solutions.This study deals with the properties of cement mortar containing different levels of manufactured sand(MS)based on quartzite,used to replace river sand.The river sand was replaced at 20%,40%,60%and 80%with MS(by weight or volume).The mechanical properties,transfer properties,and microstructure were examined and compared to a control group to study the impact of the replacement level.The results indicate that the compressive strength can be improved by increasing such a level.The strength was improved by 35.1%and 45.5%over that of the control mortar at replacement levels of 60%and 80%,respectively.Although there was a weak link between porosity and gas permeability in the mortars with manufactured sand,the gas permeability decreased with growing the replacement level.The microstructure of the MS mortar was denser,and the cement paste had fewer microcracks with increasing the replacement level. 展开更多
关键词 Manufactured sand quartzite compressive strength gas permeability MICROSTRUCTURE
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Performance Evaluation of Asphalt Concrete Based on Basalt Aggregates of Diack and Quartzite of Bakel
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作者 Mory Coulibaly Makhaly Ba +1 位作者 Macodou Thiam Babacar Diouf 《Open Journal of Civil Engineering》 2023年第4期695-705,共11页
In Senegal, basalt aggregates are the aggregates used for the production of asphalt. They are also in some condition in base layer. However, the only licensed and operated basalt quarry in the west-central part of the... In Senegal, basalt aggregates are the aggregates used for the production of asphalt. They are also in some condition in base layer. However, the only licensed and operated basalt quarry in the west-central part of the country is finished and has reached very important depths thus constituting an environmental threat. This is how quartzite present in the east of the country precisely in the department of Bakel would constitute an alternative to basalt. For this purpose, the performance of two bituminous concretes based on quartzite and basalt was compared. One is made from Diack basalt aggregates, considered as the reference aggregate for asphalt in Senegal and the other is based on Bakel quartzite aggregates, they are both class 0/14. The mechanical performance of two bituminous concretes is evaluated using the Marshall method. The results obtained from the marshall tests give compactness values between 94% and 97% representing the limits laid down in the technical specifications, the creep values for quartzite-based asphalt concrete, while respecting the limit values, are higher than those obtained with basalt aggregates. Thus showing that the former is less resistant to deformation than the former. For both bituminous mixtures, the stability values remain above the minimum value of 1000 kgf set by the specifications. The water resistance test carried out on the two bituminous concretes based on basalt aggregate and quartzite aggregate gives values of immersion/compression ratio (R’c/Rc) equal to 0.72 and 0.82 respectively. These values are above the minimum required value (0.70) in the technical specifications in Senegal. 展开更多
关键词 quartzite BASALT Bituminous Concrete Marshall Duriez
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Two types of uranium mineralization in Gulcheru quartzite:Fracture-controlled in Ambakapalle area and litho-controlled in Tummalapalle area,Cuddapah Basin,Andhra Pradesh,India 被引量:3
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作者 Sukanta Goswami Pradeep Kumar Upadhyay +2 位作者 Bhaskaran Saravanan V Natarajan Mohan Babu Verma 《China Geology》 2019年第2期142-156,共15页
The Cuddapah Basin in southern India has a potential for uranium mineralization due to some favorable factors such as its temporal, stratigraphic and tectonic settings. Systematic exploration program conducted by the ... The Cuddapah Basin in southern India has a potential for uranium mineralization due to some favorable factors such as its temporal, stratigraphic and tectonic settings. Systematic exploration program conducted by the Atomic Minerals Directorate for Exploration and Research (AMD) within the Cuddapah Basin resulting in the recognition of distinct types of uranium mineralization, viz., strata bound type, fracture/shear-controlled type and tabular type. The Gulcheru Formation which is the lowermost unit of the Cuddapah Basin is dominantly arenitic in nature. During the exploration works, a number of uranium anomalies were identified with dimensions ranging from 1 m to 1.5 km. Gulcheru quartzite hosted uranium mineralization is intermittent and inconsistent in nature. The anomalous outcrops are distributed over a strike length of ca. 60 km between Gandi in the SE and Ambakapallein the NW. Presently, two different types of uranium mineralization are characterized on the basis of field observations, mapping and structural interpretation, petro-mineralogy and geochemistry. Although the host rock is same for both types, the mechanism of uranium enrichment is totally different. The Ambakapalle uranium mineralization is controlled by fault zone and associated hydrothermal activity. Whereas, the Tummalapalle uranium mineralization is litho-controlled in nature influenced by suitable four ‘P’ factors, i.e., provenance, porositypermeability, precipitation and preservation. The geochemical characterization of Gulcheru quartzite suggest a passive margin type of provenance setting. Petro-mineralogically the quartz arenite suggests enough textural as well as mineralogical maturity. Ambakapalle quartzite is slightly strained and deformed due to faulting. Analysis of selected samples recorded 0.01% to 0.048% U3O8 and <0.01% ThO2. Petrographic observation revealed that the anomalies were appeared due to secondary uranium minerals occurring as surficial encrustations, fracture filling and lesser irregular patches. Structural analysis suggests the mineralization along E-W trace slip fault is possibly consistent in sub-surface. Tummalapalle quartzite is relatively less deformed arenitic in nature with significant enrichment in MREE. The genetic models for the two types of mineralization is totally different. 展开更多
关键词 Uranium MINERALIZATION Fracture-controlled MINERALIZATION Litho-contralled MINERALIZATION Gulcheru quartzite Hydrothermal ALTERATION Andhra Pradesh INDIA
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Microstructural Features of Garnets in Jadeite Quartzite from Dabie Mountains, China 被引量:1
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作者 Wu Xiuling Mou Tao Han Yujing Test Center, China University of Geosciences, Wuhan 430074, China Li Douxing Laboratory of Atomic Imaging of Solid, Institute of Metal Research, Academia Sinica, Shenyang 110015, China 《Journal of Earth Science》 SCIE CAS CSCD 2000年第3期158-161,共4页
Garnet is an important rock forming mineral of high pressure and ultrahigh pressure metamorphic rocks. Its popular isomorphism complicates its chemical composition and crystal structure. The selected area electron ... Garnet is an important rock forming mineral of high pressure and ultrahigh pressure metamorphic rocks. Its popular isomorphism complicates its chemical composition and crystal structure. The selected area electron diffraction (SAED) and the high resolution electron microscopy (HREM) are used in this work to study the microstructures and ultrastructures of garnets in the jadeite quartzite from Dabie Mountains, China. The microstructures of the garnet occur mainly as free dislocations, dislocation walls, stacking faults, dislocation networks and sub grain boundaries. The dislocation density is ρ=n ×10 8/cm 2 ( n =1.7—7.5) and the deformation mechanism is the dislocation glide and dynamic recovery. The superstructures of the garnet crystal revealed by HREM occur mainly as dislocations, faults, domain structures and lattice deformations, indicating the strong stress during the formation of the jadeite quartzite. 展开更多
关键词 jadeite quartzite GARNET MICROSTRUCTURE HREM.
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Effects of mechanical activation on the structural changes and microstructural characteristics of the components of ferruginous quartzite beneficiation tailings 被引量:2
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作者 Ermolovich E.A. Ermolovich O.V. 《International Journal of Mining Science and Technology》 SCIE EI CSCD 2016年第6期1043-1049,共7页
The effects of mechanical activation in a planetary mill on the structural changes and microstructural characteristics of the components of ferruginous quartzite beneficiation railings generated by wet magnetic separa... The effects of mechanical activation in a planetary mill on the structural changes and microstructural characteristics of the components of ferruginous quartzite beneficiation railings generated by wet magnetic separation process were studied using X-ray and laser diffraction methods. The results revealed the relationship between variations in the mean particle size of activated powders and the milling time. The crystallite size, microstrain, lattice parameters and unit cell volumes were determined for different milling times in powder samples of quartz, hematite, dolomite, and magnetite from the beneficiation tailings. The main trends in the variation of the crystallite size of quartz, hematite, dolomite, and magnetite as a function mean particle size of powder samples were revealed. Changes in the particle shape as a function of the activation time was also investigated. 展开更多
关键词 Ferruginous quartzite beneficiation tailings Mechanical activation Crystallites Planetary mill Microstructure Structural changes
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Crustal stabilization:Evidence from the geochemistry and U–Pb detrital zircon geochronology of quartzites from Simlipal Complex,Singhbhum Craton,India
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作者 C.S.Sindhuja Arijit Pahari +7 位作者 C.Manikyamba M.Santosh Li Tang Jyotisankar Ray K.S.V.Subramanyam Madhuparna Paul I.Gonzalez-Alvarez P.C.Sruthi 《Geoscience Frontiers》 SCIE CAS CSCD 2022年第1期46-61,共16页
Cratonic stabilization was a critical crustal process during the Hadean to Archean for the formation of cratons.The understanding of how and where this process took place is significant to evaluate the architecture of... Cratonic stabilization was a critical crustal process during the Hadean to Archean for the formation of cratons.The understanding of how and where this process took place is significant to evaluate the architecture of continents.The Singhbhum Craton of eastern India has well preserved Precambrian volcanosedimentary sequences.The Simlipal volcano-sedimentary complex of Singhbhum Craton consists of circular bands of mafic volcanic rocks interlayered with quartzites/shales/phyllites.In the present study,we report petrographic and geochemical characteristics of quartzites from Simlipal Complex coupled with U–Pb ages of detrital zircons and zircon geochemistry to understand the provenance and depositional conditions and its connection with the crustal stabilization in the Singhbhum Craton.The quartzites are texturally mature with sub-angular to sub-rounded quartz grains followed by feldspars embedded in a silty matrix.Based on modal compositions and major element ratios,these quartzites are categorized as quartz arenite and sub-lithic arenites.Trace element abundances normalized to Archean Upper Continental Crust(AUCC)display positive anomalies at U,Zr,Hf and negative anomalies at Nb.REE patterns are characterized by negative Eu anomalies(Eu/Eu^(*)=0.47–0.97)and flat HREE suggesting felsic provenance.These quartzites show depletion of LILE,enrichment of HFSE and transition metals relative to AUCC.High weathering indices such as CIA,PIA,and ICV are suggestive of moderate to intense chemical weathering.Low trace element ratios such as Th/Cr,Th/Sc,La/Sc,La/Co and Th/Co indicate a predominantly felsic source for these rocks.The overall geochemical signatures indicate passive margin deposition for these quartzites.Detrital zircons from the Simlipal quartzites yield U–Pb ages 3156±31 Ma suggesting Mesoarchean crustal heritage.The trace element geochemistry of detrital zircons suggests that the zircons are magmatic in origin and possibly derived from the 3.1 Ga anorogenic granite/granitoid provenance of Singhbhum Craton.These observations collectively indicate the Mayurbhanj Granite and Singhbhum Granite(SBG-III)provenance for these quartzites,thereby tracking the stabilization of the eastern Indian Shield/Singhbhum Craton back to Mesoarchean. 展开更多
关键词 quartzites Simlipal Complex Singhbhum Craton U-Pb geochronology Crustal stablilization
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REE Characteristics and REE Mixing Modeling of the Proterozoic Quartzites and Sandstones
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作者 H. Wani 《International Journal of Geosciences》 2017年第1期16-29,共14页
Rare earth elements (REE) in sedimentary rocks are most suitable for source rock characterization. Rare earth element data of the sandstones of the unmetamorphosed Meso-Neoproterozoic Chhattisgarh and Indravati basins... Rare earth elements (REE) in sedimentary rocks are most suitable for source rock characterization. Rare earth element data of the sandstones of the unmetamorphosed Meso-Neoproterozoic Chhattisgarh and Indravati basins and the metamorphosed Paleoproterozoic Sakoli and Saucer basins of the Bastar craton have been studied for source rock characterization. The quartzites have higher ∑R EE mean value (145 ppm) compared to the sandstones (34 ppm). The REE patterns of all the three formations of the Chandarpur Group of the Chhattisgarh basin and the Tiratgarh Formation of the Indravati basin are uniform and there are no systematic differences in REE patterns among different formations of the Chandarpur Group and the Tiratgarh Formation. The REE patterns of the quartzites are similar to the REE patterns of the sandstones. Chondrite-normalized REE patterns with LREE enrichment and a strong negative Eu anomaly of the sandstones and quartzites gives a broad hint about felsic source rocks. The source rocks are identified as Archean granite and gneiss of the Bastar craton. The REE mixing modeling of the sandstones and quartzites suggest that the exposed the Proterozoic upper crust of the Bastar craton during the sedimentation of the Paleoproterozoic Sakoli and saucerand the Meso-Neoproterozoic Chhattisgarh and Indravati basins of the Bastar craton was largely consisted of gneissic rocks (70%), with a little contribution (20%) from Late Archean (2.5 Ga) granites. The present study does not suggest any significant change in the upper crustal composition during Proterozoic in the Bastar craton. 展开更多
关键词 RARE Earth Elements SANDSTONES quartzites Source Rock PROTEROZOIC CRUSTAL Composition
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Diagnosis and Damage Assessment of Weathered Quartzite Colossi of 18<sup>th</sup>Dynasty from Karnak Temple, Egypt
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作者 Abd Elhakim A. El-Badry Abdelkareem E. Ahmed Nabil A. Bader 《Open Journal of Geology》 2017年第1期51-68,共18页
The Egyptian Pharaonic temples are traditionally made of different stones (limestone granite, diorite, or sandstone and quartzite) shaped into large heavy blocks or as Colossal statues. One of these is the colossi of ... The Egyptian Pharaonic temples are traditionally made of different stones (limestone granite, diorite, or sandstone and quartzite) shaped into large heavy blocks or as Colossal statues. One of these is the colossi of Thutmose II and Amenhotep III at Karnak temple which made out of red quartzite from Gebel el-Ahmar, located at north-east of Cairo. Quartzite is one of the famous stones that were widely used during the heights of ancient Egyptian civilization. The Colossi of Thutmose II and Amenhotep III were subjected to many exogenous and endogenous deterioration factors which causes of a severe damage of the stone materials. In this study we documented the weathering of these quartzite colossal statues using field recording and laboratory analysis to evaluate their conservation state. Weathering and deterioration aspects noted through light optical microscope (LOM), polarizing microscope (PM) and scanning electron microscope (SEM). The mineralogical characterization was performed using X-ray powder diffraction (XRD) and Energy dispersive analysis (EDX). The mineralogy and weathering study of quartzite on the Colossi of Thutmose II and Amenhotep III illustrate a succession of geochemical processes which have taken place at the colossi and it revealed that, they need for quick intervention. 展开更多
关键词 Colossi quartzite Karnak TEMPLE DETERIORATION Conservation Concepts
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Discovery of sapphifine-bearing hyperthene quartzite in the Larsemann Hills, East Antarctica, and its geological significance 被引量:1
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作者 TONGLaixi, LIU Xiaohan, XU Ping, HAN Xiuling, ZHAO Yue, REN Liudong and WANG Yanbin1. Laboratory of Lithospheric Tectonic Evolution, Institute of Geology, Chinese Academy of Sciences, Beijing 100029, China 2. Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China 《Chinese Science Bulletin》 SCIE EI CAS 1997年第4期324-328,共5页
1 Geological setting THE Larsemann Hills, East Antarctica consist mainly of Mirror, Broknes and Stornes Peninsulas and many islands(fig. 1), with an area of 60 km^2, and form part of extensive Neoproterozoic (1000 Ma)... 1 Geological setting THE Larsemann Hills, East Antarctica consist mainly of Mirror, Broknes and Stornes Peninsulas and many islands(fig. 1), with an area of 60 km^2, and form part of extensive Neoproterozoic (1000 Ma) high-grade metamorphic terranes of East Antarctica. The major outcrops in the region are composed of amphibolite to granulite facies metapelites, metapsammites, quartzites, migmatitie paragneisses, felsic orthogneisses and mafic granulites. 展开更多
关键词 sapphirine-bearing hyperthene quartzite Larsemann Hills EAST Antarctica.
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Zircon isotopic ages from magnetite quartzites of the Jianping metamorphic complex, western Liaoning Province
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作者 A.Krner A.A.Nemchin 《Chinese Science Bulletin》 SCIE EI CAS 2000年第6期547-551,共5页
Using the zircon Pb evaporation method and high precise ion microprobe analyses, zircon isotopic ages in supracrustal magnetite quartzites from Jianping metamorphic complex have been obtained. The results show that th... Using the zircon Pb evaporation method and high precise ion microprobe analyses, zircon isotopic ages in supracrustal magnetite quartzites from Jianping metamorphic complex have been obtained. The results show that the deposition of the supracrustal rocks occurred around 2 552-2 520 Ma and the peak of granulite facies metamorphism reached at about 2 487 Ma; about (1 806±16) Ma, i.e. Mid-Proterozoic, the other possible metamorphic event with relatively low intensity happened in the study area. it is speculated that a likely tectonic setting where the Jianping metamorphic complex formed is an active Continental margin that is involved in Continental collision and crustal thickening shortly after its formation. 展开更多
关键词 ZIRCON age MAGNETITE quartzite Jianping METAMORPHIC complex ARCHAEAN western Liaoning Province.
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Zeta Potential of Aggregate and Dynamic Modulus of HMA Estimation Using Aggregate Silica Content
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作者 Mouhamed Lamine Chérif Aidara Serigne Touba Thiam Alan Carter 《Open Journal of Civil Engineering》 CAS 2023年第1期35-47,共13页
The mineralogical composition of an aggregate influences its adhesion with bitumen and therefore its dynamic modulus. However, few studies have been conducted on this aspect. One of the most used properties to describ... The mineralogical composition of an aggregate influences its adhesion with bitumen and therefore its dynamic modulus. However, few studies have been conducted on this aspect. One of the most used properties to describe the impact of aggregate on the adhesiveness phenomena is the zeta potential. In this study, the first mineralogical and chemical properties were considered through the percentage of silica in the rock source of aggregates and the electric aggregate particles charge zeta. Dynamic modulus values used for regression process are determined from complex modulus test on nine asphalt concretes mix designed with aggregate types (basalt of Diack, quartzite of Bakel and Limestone of Bandia). The results showed that aggregate with high percentage of silica have higher zeta potential than aggregate with low percentage of silica. The development of a zeta potential predictive model showed a strong sensitivity to silica. The results of the complex modulus tests showed that Hot Mixture Asphalt (HMA) mixed with aggregate containing high silica contents gave better results than those mixed with aggregates containing low percentage of silica. The dynamic modulus predictive models of HMA developed shows that it is the properties of bitumen that influence more. However, the effect of silica although low, is very marked at low temperatures and high frequencies. 展开更多
关键词 Basalt of Diack quartzite of Bakel Limestone of Bandia Complex Modulus Test Binder-Aggregate Adhesiveness
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Resilient Modulus of Unbound Aggregate Base Courses from Senegal (West Africa) 被引量:1
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作者 Makhaly Ba Meissa Fall +2 位作者 Fatou Samb Déthié Sarr Mapathé Ndiaye 《Open Journal of Civil Engineering》 2011年第1期1-6,共6页
This paper presents the results of research conducted to investigate the Resilient Modulus (Mr) of unbound aggregates used as pavement layer in Senegal (West Africa) as well as the effect of water content and density ... This paper presents the results of research conducted to investigate the Resilient Modulus (Mr) of unbound aggregates used as pavement layer in Senegal (West Africa) as well as the effect of water content and density on the Resilient Modulus of the materials tested. Four different aggregates was collected from different sites within Senegal and then subjected to repeated load triaxial tests. Test results showed that the Bandia limestone is around 44% stiffer than the basalt, and 71% to 104% stiffer that the Black and the Red quartzites (GNB and GRB). The basalt is 21% to 43% stiffer than the GNB and the GRB. Basalt specimens compacted at Wopt– 2% were 30% stiffer than basalt specimens compacted at Wopt and 40% stiffer than those com- pacted at Wopt+ 2%. The Summary Resilient Modulus (SRM) at Wopt– 2% is 22% higher than SRM at Wopt and 35% higher than SRM at Wopt+ 2% for the GRB and the GNB. The SRM at Wopt– 2% is 30% higher than SRM at Wopt and 40% higher than SRM at Wopt+ 2%, for the Basalt. For the Bandia limestone, the SRM at Wopt– 2% is 81% higher than SRM at Wopt and 126% higher than SRM at Wopt+ 2%. Results show also that the Resilient Modulus increases around 25% when relative density increases from 77% to 119% and the variation is more significant at high stress states than at low stress state. Results of statistical analysis and coefficients of determination (R2) showed that the Uzan and NCHRP models are more suitable to predict the Resilient Modulus of the aggregates tested. 展开更多
关键词 Resilient MODULUS Summary Resilient MODULUS quartzite BASALT Bandia LIMESTONE Un-bound AGGREGATES
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Investigating the Depth and the Geometry of the Quarzitic Panafrican Basement Using Near-Surface 3D Seismic Refraction Tomography: Case Study of the Locality of Bakel (Senegal)
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作者 Mapathe Ndiaye Oustasse Abdoulaye Sall +3 位作者 Alassane Thiam Déthié Sarr Moustapha Badji Issa Ndoye 《International Journal of Geosciences》 2020年第6期345-359,共15页
<div style="text-align:justify;"> <span style="font-family:Verdana;">Seismic refraction investigations have been carried out in Bakel, Eastern Senegal. The purpose was to map geometrica... <div style="text-align:justify;"> <span style="font-family:Verdana;">Seismic refraction investigations have been carried out in Bakel, Eastern Senegal. The purpose was to map geometrical relationship between the existing rock types and the Panafrican quarzitic basement, which is valuable information for the project of the Bakel fluviatile port construction. Four seismic refraction profiles were acquired. The obtained data have been processed by inversion. The obtained four seismic P-wave velocity profiles have been integrated to obtain a 3D model. By comparing the outcropping geological formations with the observed seismic data at the surface, it was possible to identify the lithology corresponding to each measured range of seismic velocity for the alluvium, the weathered bed rock, and the fresh rock. The results showed that the depth of the fresh rock of the basement varies from 0 to 18 meters above the sea level, with a deepening toward the Senegal River and toward the Northern part of the studied area. The presence of alluviums and their thickness are linked to the existence of bays and gulfs. The results of this study give valuable information for the river bed dredging cost assessment prior to the port construction phase.</span> </div> 展开更多
关键词 Panafrican ALLUVIUM quartzite Seismic Refraction Tomography 3D Model Bakel Senegal
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Effect of Compaction Moisture Content on the Resilient Modulus of Unbound Aggregates from Senegal (West Africa)
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作者 Makhaly Ba Meissa Fall +1 位作者 Oustasse Abdoulaye Sall Fatou Samb 《Geomaterials》 2012年第1期19-23,共5页
This paper presents the results of research conducted to investigate the effect of compaction moisture content on Resil- ient Modulus (Mr) of unbound aggregates. Three different aggregates (GRB, Basalt and Bandia lime... This paper presents the results of research conducted to investigate the effect of compaction moisture content on Resil- ient Modulus (Mr) of unbound aggregates. Three different aggregates (GRB, Basalt and Bandia limestone) was collect- ed from different sites within Senegal and then subjected to repeated load triaxial tests. Test results showed that the ef- fect of compaction water content is more significant in the dry side than in the wet side. The compaction water content has less effect on the GRB and the Basalt than on the Bandia limestone. GRB and Basalt are cohesionless materials and allow water to drain even during the compaction procedure. Change in water content increases as the compaction water content increases because of the drainage of the excess water during the compaction and loading procedures. For GRB and Basalt, at Wopt + 1.5%, most of the excess water is drained during the compaction of the sample and continue to be drained during the Resilient Modulus test. For the Bandia limestone, this drainage is less significant due to cohesion, absorption and hydratation. 展开更多
关键词 Resilient MODULUS Summary Resilient MODULUS quartzite BASALT Bandia LIMESTONE
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Evidences by Multiscale Analysis and 2D3/4 Models from the Magnetic Anomalies and Iron Mineralization (BIF) over the DJADOM-ETA Area, Southeastern Cameroon
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作者 Justine Yandjimain Théophile Ndougsa-Mbarga +1 位作者 Arsène Meying Paul Claude Ngoumou 《Open Journal of Earthquake Research》 2020年第1期19-32,共14页
The Magnetic method is one of the best geophysical techniques used to delineate subsurface structures. This study was conducted to investigate the basement faulting and ore mineralization into the overlying geological... The Magnetic method is one of the best geophysical techniques used to delineate subsurface structures. This study was conducted to investigate the basement faulting and ore mineralization into the overlying geological cover. The GEOSOFT v8.4 software was used to process the data. Upward continuation of the residual magnetic intensity map at various altitudes and the maxima of their horizontal gradient magnetic were used to highlight faults from shallow to deep, as well as, their dips and mineralization zones. The faults with the directions E-W, ESE-WNW and ENE-WSW are identified confirming the result of [1]. This study also reveals that, the layer is affected by faults propagating from the basement upwards into the cover. Our results added additional information to the knowledge of the geological structure and the mineral resources potential in the study area. Based on the 2D3/4 modeling, the Dja Fault (DF) is revealed and highlighted sub-area marked by a magnetite/or hematite dolerite, schist and sandstone blocks, which show strong magnetization. Specifically, in this area, models are made of BIF (bounded iron formation) and BIQ (bounded iron quartzite) as dominant minerals. 展开更多
关键词 AEROMAGNETIC Anomalies Multiscale Mineralization (BIF (Bounded IRON Formation) BIQ (Bounded IRON quartzite)) HMG (Horizontal Gradient Magnetic) Faults
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Development of a Dynamic Modulus Prediction Model for Hot Mixture Asphalt and Study of the Impact of Aggregate Type and Its Electrochemical Properties
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作者 Mouhamed Lamine Chérif Aidara Makhaly Ba Alan Carter 《Open Journal of Civil Engineering》 2020年第3期213-225,共13页
The most famous model known in prediction of dynamic modulus for asphalt concretes<span style="font-family:Verdana;"> is</span><span style="font-family:Verdana;"> the Witczak and ... The most famous model known in prediction of dynamic modulus for asphalt concretes<span style="font-family:Verdana;"> is</span><span style="font-family:Verdana;"> the Witczak and Hirsh models. These models didn’t use the mineralogical and chemical properties of aggregates. Witczak models used the passing or refusal percentage to sieve diameters and Hirsh model use</span><span style="font-family:Verdana;">d</span><span style="font-family:""><span style="font-family:Verdana;"> the volumetric analysis. All models developed until now considered that the aggregates were geotechnical conforming to standards. In this study the first mineralogical and chemical properties were considered through the percentage of silica in the rock source of aggregates and the electric aggregate particles charge zeta. Dynamic modulus values used for regression process are determined from complex modulus test on nine asphalt concretes mix designed with aggregate types (basalt of Diack, quartzite of Bakel and Limestone of Bandia).</span><span style="font-family:Verdana;"> Between Twelve initial inputs</span></span><span style="font-family:Verdana;">,</span><span style="font-family:""><span style="font-family:Verdana;"> the statistical regression by exclusion process keeps only seven parameters as input for the model. The mineralogical model showed good accuracy with R</span><sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;"> equal to 0.09. The student test on the model parameters showed that all the parameters included in the model were meaningful with good p inferior to 0.05. The Fisher test on the model showed the same result. The analysis of the sensitivity of the mineralogical model to zet</span></span><span style="font-family:Verdana;">a potential showed that the dynamic modulus increase</span><span style="font-family:Verdana;">s</span><span style="font-family:Verdana;"> <span style="font-family:Verdana;">with the positive zeta-potentials and decrease</span></span><span style="font-family:Verdana;">s</span><span style="font-family:Verdana;"> with the negative zeta-potentials.</span><span style="font-family:Verdana;"> The analysis of the sensitivity of the mineralogical model to the silica showed that the dynamic modulus decreases with the increase of the silica.</span> 展开更多
关键词 Dynamic Modulus MINERALOGICAL Basalt of Diack quartzite of Bakel Limestone of Bandia Zeta Potential Silica
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Impact of Intrinsic Properties of Aggregate and Volumetric Properties of Hot Mixture Asphalt (HMA) in the Influence of the Resistance to Rutting
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作者 Mouhamed Lamine Chérif Aidara Makhaly Ba Alan Carter 《Open Journal of Civil Engineering》 2020年第3期187-194,共8页
Se<span style="font-family:Verdana;">veral studies show that properties of Hot Mixture Asphalt (HMA) mix design materials, aggregate gradation and volumetric properties had an influence on their resist... Se<span style="font-family:Verdana;">veral studies show that properties of Hot Mixture Asphalt (HMA) mix design materials, aggregate gradation and volumetric properties had an influence on their resistance to rutting. However, these properties do not impact in the same way this performance. For a given aggregate type</span><span style="font-family:Verdana;">,</span><span style="font-family:Verdana;"> an infinity aggregate gradation type can be observed, and for each type of HMA several types of bituminous binder can be used. This article aims to measure the evolution of resistance to rutting according to the three main classes of National Cooperative Highway Research Program (NCHRP) aggregate gradation (dense-graded, fine-graded and coarse-graded).</span><span style="font-family:""> </span><span style="font-family:Verdana;">To this end, a study was conducted on the measurement of rutting resistan</span><span style="font-family:Verdana;">ce for eight bituminous mixtures manufactured with two bitumen type</span><span style="font-family:Verdana;">s</span><span style="font-family:Verdana;"> and two types of manufacturing aggregates. The results showed that there is a priority order of these different parameters on the influence of the resistance to rutting. This highlights a competition between the properties of aggregate and type of granular skeleton. Indeed, for the same type of aggregate, asphalt binder type first impact</span><span style="font-family:Verdana;">s</span><span style="font-family:Verdana;"> resistance to rutting of the HMA followed by aggregate gradation, volumetric properties of the mix and finally by the angularity of the aggregates. However</span><span style="font-family:Verdana;">,</span><span style="font-family:Verdana;"> this order cannot be fixed and can depend of the intensity of each parameter.</span> 展开更多
关键词 Aggregate Gradation HMA RUTTING BASALT quartzite
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Preliminary <i>k</i>-Values of Unbound Natural Quartzitic Gravels for Mechanistic-Empirical Pavement Design
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作者 Edmund Obeng Yaw A. Tuffour +1 位作者 Daniel A. Obeng Bernard Koranteng-Yorke 《Open Journal of Civil Engineering》 2017年第4期509-526,共18页
The generalized constitutive model relating the resilient modulus (MR) of flexible pavement layer materials to stress state, adopted by the Mechanistic-Empirical Pavement Design Guide (MEPDG), contains a set of consta... The generalized constitutive model relating the resilient modulus (MR) of flexible pavement layer materials to stress state, adopted by the Mechanistic-Empirical Pavement Design Guide (MEPDG), contains a set of constants known as k-values (k1, k2, and k3) which are associated with the physical state of the layer materials. In Ghana, natural gravels constitute the predominant and sometimes the sole layer materials for most flexible pavements yet representative k-values of gravel materials, have not been determined to permit full application and implementation of the mechanistic-empirical design concept to pavements involving such materials. In this study, k-values characterising typical natural quartzitic gravels used for road construction in the country were derived by regression techniques from MR values determined using laboratory repeated load triaxial test. Using multiple linear regression technique, correlation relationships were then developed between the k-values and the physical properties of the gravels, namely, percentages of materials passing the 9.5 mm (P9.5) and 2.0 mm (P2.0) sieves, liquid limit (LL), maximum dry density (ρdmax), and optimum moisture content (wopt). The regression analysis returned k1 values which ranged between 441 and 958 with a mean of 516;k2 which varied between 0.0636 and 0.2168 with a mean value of 0.1216;and, k3 values which ranged between 0.1257 and 3.1590 with a mean value of 1.723. Contrary to what is mostly reported in literature, the analysis returned positive k3 values for all but one gravel material, suggesting stress hardening under octahedral shear stress for those materials. While an expanded sample base is required to fully characterize the whole gamut of natural gravels used in pavement construction in the country, this study on limited quartzitic gravel samples has given a good indication of strong linear correlations between the k-values and the index properties of the gravels, to permit estimates of the constants for such gravels be made where capability and opportunity for conducting resilient modulus tests do not exist.However, further work is recommended to fully characterise the exact nature of k3 values for quartzitic gravels in the country. 展开更多
关键词 Flexible Pavement Index Properties k-Values Mechanistic-Empirical Design Quartzitic GRAVEL Resilient Modulus
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