Concrete can deteriorate as a result of alkali aggregate reaction, an interaction between alkalis present in
alkaline pore solution originating from the Portland cement and reactive minerals in certain types of aggregates.
Potential reactivity of aggregates with regard to alkalis present in concrete mix can be determined by Mortar Bar
method, Chemical Method and Petrographic analysis. Of these the chemical method though is quick and does
not require a large quantity of material for testing yet have its own inherent limitations. It does not ensure
completion of reaction as the observations are limited to 24hour only and also does not assess the effect of
varying the combination of coarse and fine aggregates. A study on chemical method by allowing the reaction for
a prolonged time up to 96 hours and also on different grain size ranged matrix was carried at Central Soil and
Materials Research Station, New Delhi. Simultaneously the test results of the modified method are compared to
the existing Mortar Bar method, Chemical Method and Petrographic analysis The outcome of the studies clearly
reflects that the grain size play an important role in the reaction, the reaction time has a demarked impact on
reactivity, in the cases having a high value of silica release the choice of reduction in alkalinity as an indicator
of degree of reaction is not reliable, instead measuring remaining Na2O concentration in Sodium hydroxide
solution after the reaction seems to be much more meaningful in justifying the silica release.
1. The document examines the effect of water salinity on gold ore treated with flotation reagents using atomic force microscopy.
2. It finds that pyrite treated with copper sulfate activator and potassium amyl xanthate collector in non-saline solutions forms large masses on its surface believed to be dixanthogen, increasing the surface's attractive adhesive force due to hydrophobic interaction.
3. However, pyrite treated in saline solutions did not show the same trend and instead displayed a larger repulsive force with copper sulfate and a minor attractive force with potassium amyl xanthate, believed to be due to hydrated cations and salts interfering with surface forces.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
Application of micromechanics on alkali activated materialsTran Nam
This document discusses applying micromechanical analysis to alkali-activated materials. It identifies the intrinsic Young's modulus of the N-A-S-H gel that forms in alkali-activated fly ash and metakaolin as approximately 18 GPa using nanoindentation testing. It then develops a two-scale homogenization model combined with percolation theory to upscale the intrinsic gel properties to the macroscale, reproducing experimental data. The model also demonstrates how the N-A-S-H gel stiffens with increased packing of solid gel particles during the alkali activation process.
Optimization of temperature imposed on activator before mixinginventionjournals
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
This study examined how pH and redox potential (Eh) influence the leaching of mercury from mining waste materials. Laboratory experiments were conducted by varying the pH from 2 to 12 and Eh under different gas purging conditions. Results showed that mercury concentration in leachates increased with rising pH until pH 10.65, above which it sharply decreased. The presence of iron significantly reduced mercury concentrations by 1/10th to 1/100th. Varying the Eh had little effect on mercury leaching, except when hydrogen peroxide was added to increase Eh, which sharply increased mercury levels. Alkaline and reduced conditions enhanced mercury solubility the most.
Removal of cadmium from aqueous solution using cobalt silicate precipitation ...IJSIT Editor
This document discusses the removal of cadmium from aqueous solutions using cobalt silicate precipitation tubes (CoSPT) as an adsorbent. CoSPT was synthesized through a "silica garden" process and found to be an effective adsorbent for cadmium. Batch adsorption studies were conducted to determine the effect of contact time, adsorbent dose, initial cadmium concentration, temperature, and pH. Experimental data fit the Langmuir and Freundlich isotherm models well. Kinetic studies showed that the pseudo-second order model provided the best fit. The maximum adsorption capacity of CoSPT for cadmium was estimated to be 319 mg/g based on
This document summarizes research that evaluated the composition and performance of different fly ashes in cementitious systems. Seven fly ashes were extensively characterized through various techniques to determine their crystalline, amorphous, and bulk compositions. The ashes' reactivity and impact on cement paste properties like strength development were then evaluated. A clear link was found between ashes' glass structure, characterized by a "network ratio" parameter, and their reactivity - ashes with less stable glass structures were more reactive and improved early-age properties more. This research provides a basis for better understanding fly ash composition and using it more effectively as a cement replacement.
Optimization of iron load in a natural zeolite for heterogeneous catalysisIJRES Journal
This document summarizes research optimizing iron loading on natural zeolite for use as a heterogeneous catalyst. The researchers treated zeolite with NH4Cl, HCl, and loaded it with iron. XRD and SEM analysis showed the treatments impacted zeolite structure and iron sorption. Equilibrium adsorption isotherms were modeled using Langmuir and Freundlich equations to evaluate iron loading. Batch experiments then evaluated the zeolite/iron catalysts and one modified with a surfactant for degrading benzene in water, providing kinetic data and analysis. The goal was to develop an efficient and reusable heterogeneous catalyst for water remediation applications like the Fenton process.
1. The document examines the effect of water salinity on gold ore treated with flotation reagents using atomic force microscopy.
2. It finds that pyrite treated with copper sulfate activator and potassium amyl xanthate collector in non-saline solutions forms large masses on its surface believed to be dixanthogen, increasing the surface's attractive adhesive force due to hydrophobic interaction.
3. However, pyrite treated in saline solutions did not show the same trend and instead displayed a larger repulsive force with copper sulfate and a minor attractive force with potassium amyl xanthate, believed to be due to hydrated cations and salts interfering with surface forces.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
Application of micromechanics on alkali activated materialsTran Nam
This document discusses applying micromechanical analysis to alkali-activated materials. It identifies the intrinsic Young's modulus of the N-A-S-H gel that forms in alkali-activated fly ash and metakaolin as approximately 18 GPa using nanoindentation testing. It then develops a two-scale homogenization model combined with percolation theory to upscale the intrinsic gel properties to the macroscale, reproducing experimental data. The model also demonstrates how the N-A-S-H gel stiffens with increased packing of solid gel particles during the alkali activation process.
Optimization of temperature imposed on activator before mixinginventionjournals
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
This study examined how pH and redox potential (Eh) influence the leaching of mercury from mining waste materials. Laboratory experiments were conducted by varying the pH from 2 to 12 and Eh under different gas purging conditions. Results showed that mercury concentration in leachates increased with rising pH until pH 10.65, above which it sharply decreased. The presence of iron significantly reduced mercury concentrations by 1/10th to 1/100th. Varying the Eh had little effect on mercury leaching, except when hydrogen peroxide was added to increase Eh, which sharply increased mercury levels. Alkaline and reduced conditions enhanced mercury solubility the most.
Removal of cadmium from aqueous solution using cobalt silicate precipitation ...IJSIT Editor
This document discusses the removal of cadmium from aqueous solutions using cobalt silicate precipitation tubes (CoSPT) as an adsorbent. CoSPT was synthesized through a "silica garden" process and found to be an effective adsorbent for cadmium. Batch adsorption studies were conducted to determine the effect of contact time, adsorbent dose, initial cadmium concentration, temperature, and pH. Experimental data fit the Langmuir and Freundlich isotherm models well. Kinetic studies showed that the pseudo-second order model provided the best fit. The maximum adsorption capacity of CoSPT for cadmium was estimated to be 319 mg/g based on
This document summarizes research that evaluated the composition and performance of different fly ashes in cementitious systems. Seven fly ashes were extensively characterized through various techniques to determine their crystalline, amorphous, and bulk compositions. The ashes' reactivity and impact on cement paste properties like strength development were then evaluated. A clear link was found between ashes' glass structure, characterized by a "network ratio" parameter, and their reactivity - ashes with less stable glass structures were more reactive and improved early-age properties more. This research provides a basis for better understanding fly ash composition and using it more effectively as a cement replacement.
Optimization of iron load in a natural zeolite for heterogeneous catalysisIJRES Journal
This document summarizes research optimizing iron loading on natural zeolite for use as a heterogeneous catalyst. The researchers treated zeolite with NH4Cl, HCl, and loaded it with iron. XRD and SEM analysis showed the treatments impacted zeolite structure and iron sorption. Equilibrium adsorption isotherms were modeled using Langmuir and Freundlich equations to evaluate iron loading. Batch experiments then evaluated the zeolite/iron catalysts and one modified with a surfactant for degrading benzene in water, providing kinetic data and analysis. The goal was to develop an efficient and reusable heterogeneous catalyst for water remediation applications like the Fenton process.
This document summarizes research on using activated Strychnos Nux-Vomica L Nano Carbon to remove Chromium (VI) ions from aqueous solution. Batch adsorption experiments were conducted to determine the effect of parameters such as contact time, initial metal concentration, adsorbent dose, pH, interfering ions, and temperature on the adsorption process. The results showed that adsorption capacity increased with temperature, reached equilibrium within 40 minutes, and was most effective at low pH between 2-7. Kinetic and thermodynamic models indicated the adsorption was physical and endothermic in nature. Overall, the study demonstrated activated Strychnos Nux-Vomica L Nano Carbon to be an effective ad
This document studies the suitability of using incinerated sewage sludge ash (ISSA) to produce geopolymer concrete as a partial replacement for fly ash. Key findings include:
1) XRF testing showed that ISSA has high concentrations of SiO2 and Al2O3 similar to fly ash, making it a potential candidate for geopolymer concrete.
2) Concrete made with only ISSA did not develop significant strength, but strength decreased gradually as ISSA percentage increased in mixes partially replacing fly ash up to 20%.
3) Concrete with up to 15% ISSA replacement was considered average quality and absorption, allowing potential use for less strength-critical applications.
4)
Characterization of mining tailings containing sulfides and carbonates applyi...Judson Arantes
Acid mine drainage (AMD) is the process resulting from the oxidation of sulfides exposed to the action of oxygen and water. The characterization of the minerals likely the formation and neutralization of AMD is important for the follow and evaluation of environmental impact. The analysis of X-ray diffraction (XRD) together with the Rietveld method is presented as a promising alternative to favor the identification and quantification of mineral phases. The results of the static test ANC achieved by accounting for carbonates consumed during the test, were correlated with the results obtained by the characterization techniques of X-ray diffraction (XRD) combined with the Rietveld method. The highest concentration of carbonate buffering found in AM2E, which may explain the static test results to be neutralizing for the sample. The major phases identified for both samples were aluminosilicates and quartz, with greater than 70% by weight levels.
V mn-mcm-41 catalyst for the vapor phase oxidation of o-xylenesunitha81
This document describes a study investigating V and Mn incorporated mesoporous molecular sieves for the vapor phase oxidation of o-xylene. Mesoporous monometallic V-MCM-41, Mn-MCM-41, and bimetallic V-Mn-MCM-41 molecular sieves were synthesized and characterized. Their activity was measured for the gas phase oxidation of o-xylene to phthalic anhydride. Among the catalysts, V-MCM-41 with Si/V = 50 exhibited the highest activity and selectivity towards producing phthalic anhydride under the experimental conditions. The physico-chemical properties of the catalysts, including metal content, surface area,
This document describes an experimental study on treating landfill leachate concentrate by coagulation. The document includes sections on materials and methods, results and discussion, and conclusion. For the materials and methods, it describes the experimental apparatus including a jar tester and centrifuge. It also describes the leachate sample from a landfill in Germany and the coagulants tested - ferric chloride, aluminum sulfate, and ferrous sulfate. The experimental procedure involves jar testing to mix the coagulants into the leachate at different dosages and pH levels, followed by centrifugation and analysis of total organic carbon (TOC) removal.
Enhanced fluidized bed methanation over a Ni Al2O3 catalyst for production of...Pengcheng Li
This document summarizes a study that investigated the fluidization behavior and CO methanation performance of a Ni/Al2O3 catalyst in a fluidized bed reactor for producing synthetic natural gas. The researchers found that the pure Ni/Al2O3 catalyst failed to properly fluidize on its own due to particle sizes between 10 and 100 μm, but fluidization was improved by adding larger Al2O3 particles. Methanation performance in the fluidized bed reactor increased substantially with the Al2O3 addition. Temperature was found to control the methanation reaction mechanism, with surface reactions dominating at lower temperatures and external diffusion controlling at higher temperatures. Stability tests showed the fluidized bed reactor had higher CO conversion, methane selectivity
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
0216-NEW Dissolution of Biosolid-Borne Metals of SoilsStephanie Lara
This study analyzed how different concentrations of organic acid mixtures extracted metals from biosolid-treated soils at varying pH levels. Metals extracted decreased with increasing pH. Cadmium, copper, nickel, and zinc were more readily extracted compared to chromium and lead. Higher organic acid mixture concentrations extracted more metals, with the 0.1M concentration extracting the greatest amounts. The study found metals in biosolid-treated soils were extracted in correlation with organic acid mixtures, with extraction decreasing in the order of cadmium, copper, nickel, zinc, chromium, and lead.
The document investigates the effects of varying deposition parameters on the structure and corrosion resistance of hydroxyapatite (HA) coatings electrodeposited onto Ti-6Al-4V alloy samples. X-ray diffraction and scanning electron microscopy were used to characterize the crystal structure and morphology of the coatings deposited under different conditions. Potentiodynamic polarization measurements in simulated body fluid evaluated the corrosion behavior. The optimal deposition parameters were found to be an applied voltage of 9 volts, pH value of 5.5, temperature of 25°C, and deposition time of 30 minutes, which yielded coatings with the best structural and corrosion-resistant properties.
This document characterizes aqueous immersion solutions of novel environmentally friendly corrosion inhibitors used to inhibit corrosion of mild steel substrates. The immersion solutions were analyzed qualitatively by visual observation of color changes and quantitatively by measuring pH, conductivity, and oxidation-reduction potential (ORP) before and after immersion. The results showed that most inhibitor solutions decreased in ORP by about 350 mV and had inhibition efficiencies between 50-100%. Exceptions were solutions containing zinc/calcium gluconates or vanadate esters, which changed ORP less. pH changes correlated with inhibition ability, with better inhibitors increasing pH slightly and poor inhibitors increasing pH more. Conductivity generally decreased for good inhibitors and increased for a poor inhibitor. The
The document summarizes research on the phase transformation of sol-gel titania containing silica. Key findings include:
1) The addition of 5-10% silica to titania increases the specific surface area of the material from 89 m2/g to over 200 m2/g. Using ethanol as the solvent medium achieved the highest surface area of 232 m2/g.
2) The addition of silica increases the anatase-rutile phase transformation temperature of titania from around 800°C to higher temperatures.
3) The phase transformation was studied using X-ray diffraction and impedance spectroscopy. The addition of methanol or ethanol was found to enhance the formation of the rutile
Treatment of wastewater from chrome plating industry by ion exchange methodeSAT Journals
Abstract In the present work an attempt has been made to evaluate the efficiency of removal Cr(VI) from chrome plating industry wastewater by using fresh and reconditioned strong base anion exchanger Tulsion A-27(MP). The Experimental data is evaluated by plotting breakthrough curves and by employing Bohart-Adams Model. The maximum removal (80%) of Cr(VI) from plating wastewater is obtained at 14cm column bed height and flowrate 1mL/min for 1144.39mg/L of influent Cr(VI) concentration. The breakthrough curves for reconditioned and fresh resins indicates that breakthrough occurs early with decrease in bed height, increase in flow rate and influent Cr(VI) concentration. Regeneration of exhausted resin is also studied by using 2M NaCl and 2M HCl. Keywords: Chromium (VI) removal; Reused Anion-exchange resin; chrome plating industry wastewater;
This document summarizes an experiment investigating the electrochemical behavior of carbon steel used for nuclear reactor containment buildings. Potentiodynamic, potentiostatic, and galvanostatic polarization techniques were used to study the steel's behavior in Ca(OH)2 solutions with varying NaCl concentrations. It was found that pitting occurred on the steel in solutions above a certain chloride concentration threshold that decreased with increasing chloride levels. Galvanostatic tests determined the chloride threshold conditions for depassivation of the pre-passivated steel. Optical microscopy of polarized samples confirmed localized corrosion above the threshold.
Brian Wayne Butler has over 7 years of experience in analytical chemistry, protein chemistry, amyloid fibril research, and environmental chemistry. He holds an M.S. in Chemistry and B.S. in Chemistry and Biochemistry from Old Dominion University. Currently he works as a Shift Manager at Advance Auto Parts, where he provides customer service and ensures high standards. Previously he has worked as a Laboratory Technician performing coal analysis and wastewater testing, as well as a Teaching Assistant for chemistry labs.
Ghoorah et al_2014_Selection of acid for weak acid processing of wollastonite...Reydick D Balucan
This document evaluates three weak organic acids (formic, acetic, and DL-lactic acid) for extracting calcium from wollastonite at temperatures between 22°C and 80°C. Experiments found that formic acid achieved the highest calcium extraction rate of 26(±7) × 10−5 mol m−2 s−1 at 80°C, followed by acetic acid and DL-lactic acid. Activation energies indicated the initial dissolution in formic acid was diffusion controlled, while kinetic limitations controlled dissolution in acetic and DL-lactic acids. Formic acid showed the best performance for calcium extraction and potential for mineral carbonation.
1) The document examines the role of various catalysts (HCl, H2SO4, CH3COOH, HF, NH4OH) in the fabrication of silica films using a sol-gel process.
2) It was found that different catalysts can have dramatic effects on the porosity, optical quality, shrinkage, thickness, structural evolution during thermal treatment, and stress of the films. For example, using H2SO4 instead of HCl as the catalyst increased the porosity of thermally treated films from 2.8% to 31%.
3) Experiments were conducted to study the effects of various catalysts on silica films fabricated via spin coating of precursor solutions and subsequent thermal
1991_Sensitivity to Iron Impurity Content of Corrosion Rate of Mg-15Al_Cotton...James D. Cotton
The corrosion rates of extrusions produced from rapidly-solidified Mg-15wt%AI alloy powder containing varying levels of iron (Fe) impurity (0.003-0.020wt%) were studied. Trace amounts of Fe were found to have a strong exponential effect on the corrosion rate, consistent with previous studies. However, the sensitivity to Fe content was markedly lower for the rapidly-solidified alloys compared to conventionally-cast alloys. This effect is explained by the microstructural refinement produced by rapid solidification, which decreases the scale of microstructure and distributes corrosion more evenly. Both pitting and filiform corrosion were observed and characterized using various microscopy techniques.
The Influence of Calcined Clay Pozzolan, Low-Cao Steel Slag and Granite Dust ...IJERA Editor
The influence of low CaO steel slag, calcined clay and granite dust on the alkali-silica reaction was investigated over a period of 35 days under accelerated curing conditions. The mineral admixtures were used to replace varying portions of high alkali Portland limestone cement up to an admixture content of 25% in order to study their effect on the alkali-silica reaction (ASR). Portland limestone cement used for the study had a total Na2Oeq of 4.32. XRD analysis of hydrated mortar bar samples confirmed the formation of an expansive sodium silica gel in the reference Portland cement mortar bar as the agent responsible for ASR. Stable calcium silicates were formed in the mortar bars containing calcined clay in increasing quantities whilst the presence of the sodium silicate gel decreased.The occurrence of these stable silicates in hydrated samples containing steel slag and granite dust was however minimal, compared to calcined clay cement mortars. The highest expansion was recorded for granite dust mortar bars, reaching a maximum of 25.98% at 35 days. Mortar-bar expansion decreased as calcined clay content in the cement increased;mortar bars with 25% calcined clay were the least expansive recording expansion less than 0.1% at all test ages. Whilst the expansion was reduced by between 42.5% and 107.8% at 14 days with increasing calcined clay content, expansion rather increased between 36.8% and 169.5% at 14 days with increasing granite dust content.Steel slag mortar bars experienced reduction in 14 days expansion between 14.3% - 46.2%.The study confirms that steel slag and calcined clay pozzolan have greater influence on ASR in mortar bars than granite dust and shows that calcined clay and low CaO steel slag could be considered as remedial admixtures for ASR at replacement levels of 25% and 15% respectively.
2019_PED_Static dissolution-induced 3D pore network modification.pdfSpariANDRIA
The document discusses how static dissolution experiments were conducted on two types of carbonate rock samples (argillaceous limestone and grain limestone) at different temperatures to determine the effect on pore network development. The relationship between calcium ion concentration and time showed that dissolution followed first-order reaction kinetics. Pore network attributes like pore size distribution, pore throat radius and length, and permeability were analyzed before and after dissolution using X-ray microtomography. The results showed that while temperature did not significantly impact pore size variation, pore attributes in the grain limestone saw more changes, indicating heterogeneity of the rock controls dissolution. Permeability increased by up to 1,000 times after dissolution for both rock types.
This document investigates the effects of adding slag and limestone powder to alkali-activated metakaolin. Tests were conducted on mixtures with 0-40% slag replacement and 0-20% limestone powder addition. Results showed that slag decreased setting time and initially increased compressive strength up to an optimal slag content. Limestone at 15% improved strength but did not affect reaction products. Analysis using XRD, FTIR and SEM showed changes in reaction products with slag but not limestone, indicating limestone acts as a non-reactive filler.
STUDY THE CORRELATION OF CLINKER QUALITY, RESIDE, PSD ON THE PERFORMANCE OF P...IAEME Publication
This research establishes the correlation between clinker quality, residue, particle size distribution and performance behaviour of cement. Different qualities of clinker were identified to understand the influence of mineralogy on the performance of cement. Chemical and mineralogical evaluation of clinker and gypsum were carried out as per the Indian specified standards, XRD and Optical microscopy. Cement samples were prepared by inter mixing of clinker and gypsum with 95 and 5% respectively for different fineness zones such as 225, 250, 275, 300, 325 and 350 m2/kg. The resultant samples were studied for residue, particle size distribution and performance evaluation as per IS 4031. It was observed that clinker quality plays an important role to achieve the desired performance characteristics in addition to the residue and particle size distribution of the cements.
This document summarizes research on using activated Strychnos Nux-Vomica L Nano Carbon to remove Chromium (VI) ions from aqueous solution. Batch adsorption experiments were conducted to determine the effect of parameters such as contact time, initial metal concentration, adsorbent dose, pH, interfering ions, and temperature on the adsorption process. The results showed that adsorption capacity increased with temperature, reached equilibrium within 40 minutes, and was most effective at low pH between 2-7. Kinetic and thermodynamic models indicated the adsorption was physical and endothermic in nature. Overall, the study demonstrated activated Strychnos Nux-Vomica L Nano Carbon to be an effective ad
This document studies the suitability of using incinerated sewage sludge ash (ISSA) to produce geopolymer concrete as a partial replacement for fly ash. Key findings include:
1) XRF testing showed that ISSA has high concentrations of SiO2 and Al2O3 similar to fly ash, making it a potential candidate for geopolymer concrete.
2) Concrete made with only ISSA did not develop significant strength, but strength decreased gradually as ISSA percentage increased in mixes partially replacing fly ash up to 20%.
3) Concrete with up to 15% ISSA replacement was considered average quality and absorption, allowing potential use for less strength-critical applications.
4)
Characterization of mining tailings containing sulfides and carbonates applyi...Judson Arantes
Acid mine drainage (AMD) is the process resulting from the oxidation of sulfides exposed to the action of oxygen and water. The characterization of the minerals likely the formation and neutralization of AMD is important for the follow and evaluation of environmental impact. The analysis of X-ray diffraction (XRD) together with the Rietveld method is presented as a promising alternative to favor the identification and quantification of mineral phases. The results of the static test ANC achieved by accounting for carbonates consumed during the test, were correlated with the results obtained by the characterization techniques of X-ray diffraction (XRD) combined with the Rietveld method. The highest concentration of carbonate buffering found in AM2E, which may explain the static test results to be neutralizing for the sample. The major phases identified for both samples were aluminosilicates and quartz, with greater than 70% by weight levels.
V mn-mcm-41 catalyst for the vapor phase oxidation of o-xylenesunitha81
This document describes a study investigating V and Mn incorporated mesoporous molecular sieves for the vapor phase oxidation of o-xylene. Mesoporous monometallic V-MCM-41, Mn-MCM-41, and bimetallic V-Mn-MCM-41 molecular sieves were synthesized and characterized. Their activity was measured for the gas phase oxidation of o-xylene to phthalic anhydride. Among the catalysts, V-MCM-41 with Si/V = 50 exhibited the highest activity and selectivity towards producing phthalic anhydride under the experimental conditions. The physico-chemical properties of the catalysts, including metal content, surface area,
This document describes an experimental study on treating landfill leachate concentrate by coagulation. The document includes sections on materials and methods, results and discussion, and conclusion. For the materials and methods, it describes the experimental apparatus including a jar tester and centrifuge. It also describes the leachate sample from a landfill in Germany and the coagulants tested - ferric chloride, aluminum sulfate, and ferrous sulfate. The experimental procedure involves jar testing to mix the coagulants into the leachate at different dosages and pH levels, followed by centrifugation and analysis of total organic carbon (TOC) removal.
Enhanced fluidized bed methanation over a Ni Al2O3 catalyst for production of...Pengcheng Li
This document summarizes a study that investigated the fluidization behavior and CO methanation performance of a Ni/Al2O3 catalyst in a fluidized bed reactor for producing synthetic natural gas. The researchers found that the pure Ni/Al2O3 catalyst failed to properly fluidize on its own due to particle sizes between 10 and 100 μm, but fluidization was improved by adding larger Al2O3 particles. Methanation performance in the fluidized bed reactor increased substantially with the Al2O3 addition. Temperature was found to control the methanation reaction mechanism, with surface reactions dominating at lower temperatures and external diffusion controlling at higher temperatures. Stability tests showed the fluidized bed reactor had higher CO conversion, methane selectivity
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
0216-NEW Dissolution of Biosolid-Borne Metals of SoilsStephanie Lara
This study analyzed how different concentrations of organic acid mixtures extracted metals from biosolid-treated soils at varying pH levels. Metals extracted decreased with increasing pH. Cadmium, copper, nickel, and zinc were more readily extracted compared to chromium and lead. Higher organic acid mixture concentrations extracted more metals, with the 0.1M concentration extracting the greatest amounts. The study found metals in biosolid-treated soils were extracted in correlation with organic acid mixtures, with extraction decreasing in the order of cadmium, copper, nickel, zinc, chromium, and lead.
The document investigates the effects of varying deposition parameters on the structure and corrosion resistance of hydroxyapatite (HA) coatings electrodeposited onto Ti-6Al-4V alloy samples. X-ray diffraction and scanning electron microscopy were used to characterize the crystal structure and morphology of the coatings deposited under different conditions. Potentiodynamic polarization measurements in simulated body fluid evaluated the corrosion behavior. The optimal deposition parameters were found to be an applied voltage of 9 volts, pH value of 5.5, temperature of 25°C, and deposition time of 30 minutes, which yielded coatings with the best structural and corrosion-resistant properties.
This document characterizes aqueous immersion solutions of novel environmentally friendly corrosion inhibitors used to inhibit corrosion of mild steel substrates. The immersion solutions were analyzed qualitatively by visual observation of color changes and quantitatively by measuring pH, conductivity, and oxidation-reduction potential (ORP) before and after immersion. The results showed that most inhibitor solutions decreased in ORP by about 350 mV and had inhibition efficiencies between 50-100%. Exceptions were solutions containing zinc/calcium gluconates or vanadate esters, which changed ORP less. pH changes correlated with inhibition ability, with better inhibitors increasing pH slightly and poor inhibitors increasing pH more. Conductivity generally decreased for good inhibitors and increased for a poor inhibitor. The
The document summarizes research on the phase transformation of sol-gel titania containing silica. Key findings include:
1) The addition of 5-10% silica to titania increases the specific surface area of the material from 89 m2/g to over 200 m2/g. Using ethanol as the solvent medium achieved the highest surface area of 232 m2/g.
2) The addition of silica increases the anatase-rutile phase transformation temperature of titania from around 800°C to higher temperatures.
3) The phase transformation was studied using X-ray diffraction and impedance spectroscopy. The addition of methanol or ethanol was found to enhance the formation of the rutile
Treatment of wastewater from chrome plating industry by ion exchange methodeSAT Journals
Abstract In the present work an attempt has been made to evaluate the efficiency of removal Cr(VI) from chrome plating industry wastewater by using fresh and reconditioned strong base anion exchanger Tulsion A-27(MP). The Experimental data is evaluated by plotting breakthrough curves and by employing Bohart-Adams Model. The maximum removal (80%) of Cr(VI) from plating wastewater is obtained at 14cm column bed height and flowrate 1mL/min for 1144.39mg/L of influent Cr(VI) concentration. The breakthrough curves for reconditioned and fresh resins indicates that breakthrough occurs early with decrease in bed height, increase in flow rate and influent Cr(VI) concentration. Regeneration of exhausted resin is also studied by using 2M NaCl and 2M HCl. Keywords: Chromium (VI) removal; Reused Anion-exchange resin; chrome plating industry wastewater;
This document summarizes an experiment investigating the electrochemical behavior of carbon steel used for nuclear reactor containment buildings. Potentiodynamic, potentiostatic, and galvanostatic polarization techniques were used to study the steel's behavior in Ca(OH)2 solutions with varying NaCl concentrations. It was found that pitting occurred on the steel in solutions above a certain chloride concentration threshold that decreased with increasing chloride levels. Galvanostatic tests determined the chloride threshold conditions for depassivation of the pre-passivated steel. Optical microscopy of polarized samples confirmed localized corrosion above the threshold.
Brian Wayne Butler has over 7 years of experience in analytical chemistry, protein chemistry, amyloid fibril research, and environmental chemistry. He holds an M.S. in Chemistry and B.S. in Chemistry and Biochemistry from Old Dominion University. Currently he works as a Shift Manager at Advance Auto Parts, where he provides customer service and ensures high standards. Previously he has worked as a Laboratory Technician performing coal analysis and wastewater testing, as well as a Teaching Assistant for chemistry labs.
Ghoorah et al_2014_Selection of acid for weak acid processing of wollastonite...Reydick D Balucan
This document evaluates three weak organic acids (formic, acetic, and DL-lactic acid) for extracting calcium from wollastonite at temperatures between 22°C and 80°C. Experiments found that formic acid achieved the highest calcium extraction rate of 26(±7) × 10−5 mol m−2 s−1 at 80°C, followed by acetic acid and DL-lactic acid. Activation energies indicated the initial dissolution in formic acid was diffusion controlled, while kinetic limitations controlled dissolution in acetic and DL-lactic acids. Formic acid showed the best performance for calcium extraction and potential for mineral carbonation.
1) The document examines the role of various catalysts (HCl, H2SO4, CH3COOH, HF, NH4OH) in the fabrication of silica films using a sol-gel process.
2) It was found that different catalysts can have dramatic effects on the porosity, optical quality, shrinkage, thickness, structural evolution during thermal treatment, and stress of the films. For example, using H2SO4 instead of HCl as the catalyst increased the porosity of thermally treated films from 2.8% to 31%.
3) Experiments were conducted to study the effects of various catalysts on silica films fabricated via spin coating of precursor solutions and subsequent thermal
1991_Sensitivity to Iron Impurity Content of Corrosion Rate of Mg-15Al_Cotton...James D. Cotton
The corrosion rates of extrusions produced from rapidly-solidified Mg-15wt%AI alloy powder containing varying levels of iron (Fe) impurity (0.003-0.020wt%) were studied. Trace amounts of Fe were found to have a strong exponential effect on the corrosion rate, consistent with previous studies. However, the sensitivity to Fe content was markedly lower for the rapidly-solidified alloys compared to conventionally-cast alloys. This effect is explained by the microstructural refinement produced by rapid solidification, which decreases the scale of microstructure and distributes corrosion more evenly. Both pitting and filiform corrosion were observed and characterized using various microscopy techniques.
The Influence of Calcined Clay Pozzolan, Low-Cao Steel Slag and Granite Dust ...IJERA Editor
The influence of low CaO steel slag, calcined clay and granite dust on the alkali-silica reaction was investigated over a period of 35 days under accelerated curing conditions. The mineral admixtures were used to replace varying portions of high alkali Portland limestone cement up to an admixture content of 25% in order to study their effect on the alkali-silica reaction (ASR). Portland limestone cement used for the study had a total Na2Oeq of 4.32. XRD analysis of hydrated mortar bar samples confirmed the formation of an expansive sodium silica gel in the reference Portland cement mortar bar as the agent responsible for ASR. Stable calcium silicates were formed in the mortar bars containing calcined clay in increasing quantities whilst the presence of the sodium silicate gel decreased.The occurrence of these stable silicates in hydrated samples containing steel slag and granite dust was however minimal, compared to calcined clay cement mortars. The highest expansion was recorded for granite dust mortar bars, reaching a maximum of 25.98% at 35 days. Mortar-bar expansion decreased as calcined clay content in the cement increased;mortar bars with 25% calcined clay were the least expansive recording expansion less than 0.1% at all test ages. Whilst the expansion was reduced by between 42.5% and 107.8% at 14 days with increasing calcined clay content, expansion rather increased between 36.8% and 169.5% at 14 days with increasing granite dust content.Steel slag mortar bars experienced reduction in 14 days expansion between 14.3% - 46.2%.The study confirms that steel slag and calcined clay pozzolan have greater influence on ASR in mortar bars than granite dust and shows that calcined clay and low CaO steel slag could be considered as remedial admixtures for ASR at replacement levels of 25% and 15% respectively.
2019_PED_Static dissolution-induced 3D pore network modification.pdfSpariANDRIA
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The past decades of research is diverted primarily in making concrete without cement or atleast partially replacing by suitable alternatives. For its availability and problems associated with, flyash has been given priority to use in concrete in high volume or total replacement of cement resulting in geopolymer concrete using activated flyash of low calcium type as the source material. However, few are dealt on the high calcium flyash that too mainly on achieving the required compressive strength and not much on the short term engineering properties like consistency and setting characteristicseven though itis essential to establish the time available for placing, compaction and transport of geopolymer. Therefore, a fundamental study on the setting characteristics and strength development of high calcium flyash based geopolymer with varying concentration of Sodium hydroxide(8-14M),varying liquid ratios (1.5-3.0) of the activator and curing at ambient and 65oCtemperature is made.It is observed that the consistency of flyash based geopolymer increases with increase of concentration of NaOH and is not at all influenced by the liquid ratios considered but, the setting time is reduced by oven curing obviously. Also, the mortar strength is atleast 10% more for hot curing than ambient curing.
SYNTHESIS AND CHARACTERIZATION OF KAOLINITE COATED WITH CU-OXIDE AND ITS EFFE...Premier Publishers
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This document summarizes a study on producing geopolymer mortar using silica waste as a raw material. Some key findings:
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This paper presents an experimental result on the behavior of fly ash and slag based geopolymer concrete exposed to 5% sulphate solutions for 3.5 months of G30 and G50 which are equivalent to M30 and M50 grades respectively. The test specimens were cast and after one day rest period, half of the specimens were cured in an oven at 60°C for 24 hours and the remaining period cured in sun light until the testing is done and remaining half of the specimens were ambient cured. After 28 days the specimens were immersed in sulphates such as Na2SO4 and MgSO4 for 15, 45, 75 and 105 days then tested on 15th, 45th, 75th and 105th day according to codal procedures and the results are compared with the controlled concrete. From the test results, it is observed that the geopolymer concrete has better resistance to sulphates attack than controlled concrete.
Modification of mesoporous silica SBA-15 with different organic molecules to ...Iranian Chemical Society
The recognition of the biologically and environmentally important ions is of great interest in the field of chemical sensors in recent years. The fluorescent sensors as a powerful optical analytical technique for the detection of low level of various analytes such as anions and metal cations have been progressively developed due to the simplicity, cost effective, and selectivity for monitoring specific analytes in various systems. Organic-inorganic hybrid nanomaterials have important advantages as solid chemosensors and various innovative hybrid materials modified by fluorescence molecules were recently prepared. On the other hand, the homogeneous porosity and large surface area of mesoporous silica make it a promising inorganic support. SBA-15 as a two-dimensional hexagonal mesoporous silica material with stable structure, thick walls, tunable pore size, and high specific surface area is a valuable substrate for modification with different organic chelating groups. This review highlights the fluorescent chemosensors for ionic species based on modification of the mesoporous silica SBA-15 with different organic molecules, which have been recently developed from our laboratory.
Raman time-resolved ion exchange studies were conducted on natrolite to understand ion exchange mechanisms. There were two steps observed: 1) softening of ring structures as potassium ions began exchanging for sodium, and 2) rapid distortion of rings allowing potassium to migrate after some exchange. Future work aims to better understand structural transitions and increase ion exchange effectiveness for industrial applications like wastewater filtration.
This document summarizes a study that investigated replacing part of the quartz component in autoclave cellular concrete with the aluminosilicate rock perlite. The study found that perlite actively participated in chemical reactions during curing, producing hydrated calcium silicates that increased the strength of the concrete. Specifically, replacing 15% of the quartz with perlite increased the compressive strength by 35% and decreased the density by 20%, while maintaining suitable physical and mechanical properties. Analysis showed that the perlite contributed to the formation of 11Å-(Al)-tobermorite and reduced the amount of metastable α-CSH phase present. The optimal microstructure was achieved with 15% replacement of quartz by perlite.
Growth and Characterizations of Pure and Calcium Doped Cadmium Tartrate Cryst...IJERA Editor
In the present course of investigation, pure and calcium doped cadmium tartrate crystals were grown in silica gel at room temperature. The optimum conditions were obtained by varying various parameters such as pH of gel, concentration of gel, gel setting time, concentration of reactants etc. Crystals having different morphologies were obtained such as whitish semitransparent, star shaped, needle shaped. Especially, effect of doping of calcium into cadmium tartrate has been studied with respect of size and transparency. It is found that doping enhances the size and transparency of the crystals. As-grown crystals were characterized using scanning electronic microscope (SEM), UV, Energy dispersive X-ray spectroscopy (EDAX).
Modifying of Float Glass Surface with Silver Nanoparticles by Ion - Exchangeinventionjournals
In this study we treated float glass samples in melts of silver containing salts. Our aims are to study the processes of Ag nanoparticle formation in order to clarify the most likely mechanism of colour and nanostructuring processes in the modified surface layer. The UV-VIS spectra show an absorption peak around 450 nm as a prove for colloidal silver particle formation. The cut-off wavelength of the transmission varies from 400 to 520 nm. The process of particle formation is studied by SEM and XRD. The structural changes in the glassy matrix are studied using DRIFT spectroscopy. The IR spectra proof that the structure of the glasses was modified mainly by the shift of the main stretching vibration in the 1050 – 1100 cm-1 spectral range. The analysis of the results of spectroscopic and microscopic studies allow conclusions to be drawn on the influence of the ion exchange time (5–60 min), composition of the salt melt (1-5 mol% AgNO3, 95-99 mol% NaNO3) and the additional heat treatment (700 - 900°C, 60 min) on the nanoparticle sizes, optical characteristics and structural changes in the surface layer of the glasses.
Corrosion studies of colmonoy - 6 in nitric acid during gadolinium removal st...RAMASUBBU VELAYUTHAM
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Corrosion Behaviour of 6061 Al-SiC Composites in KOH MediumEditor IJCATR
The present research work deals with the corrosion behaviour of 6061 Al-15% (vol) SiC(P) composites. The addition of the
reinforcement like SiC to Aluminium has been reported to decrease the corrosion resistance of the matrix due to several reasons, one
of them being galvanic action between the reinforcement and the matrix. In the present work, the corrosion behaviour of 6061 Al-15%
(vol) SiC(P) composites in KOH at different concentration (0.5M, 1M, 1.5M) and different temperature (300C, 350C, 400C, 450C, 500C)
was determined by Tafel extrapolation technique. The inhibition action of 8-Hydroxyquinoline on corrosion behaviour of 6061 Al-
15% (vol) SiC(P) composites in KOH at different concentration of inhibitor (200ppm, 400ppm); different concentration of medium
(0.5M, 1M,1.5M) and different temperature (300C, 350C, 400C, 450C, 500C) was investigated. The results indicate that corrosion rate
of Al-SiC composite in KOH increases as the concentration of medium increases and also as temperature of medium increases. The
results indicate that the inhibitor is moderately effective in inhibiting the corrosion of 6061 Al-15% (vol) SiC(P) composites. As the
inhibitor concentration increases, the corrosion rate decreases. The surface morphology of the metal surface was investigated using
scanning electron microscope (SEM). Activation energy was evaluated using Arrhenius equation, and enthalpy of activation and
entropy of activation values were calculated using transition state equation
This document summarizes research on a novel nanoporous sorbent material for removing mercury from coal plant wastewater. The material uses a mesoporous silica substrate functionalized with self-assembled thiol monolayers. Laboratory experiments showed the material could adsorb over 98% of mercury from simulated coal plant effluent, with an maximum adsorption capacity of 625 mg Hg per gram. Mercury adsorption was not significantly impacted by pH, ionic strength, or presence of other metals. The thiol-functionalized sorbent selectively binds mercury through soft acid-base interactions between mercury and thiol groups.
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Solid catalysts are of great advantages in alkylation reaction due to heterogenous reaction which makes separation of catalysts very easy and environment friendly. Here, sulfated and borate zirconia catalysts are used to search for ortho-xylene with Toluene & methanol. To find a new path to get o-xylene, catalysts surface was studied and a new mesoporous borate zirconia catalyst was prepared. Mesoporous Borate Zirconia had showed a very efficient path to manufature o-xylene.
This document analyzes the effects of alkaline and acid solutions on the mechanical properties of glass/epoxy composites. It finds that:
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2) The alkaline sodium hydroxide solution promotes a higher decrease in flexural properties than the acid hydrochloric solution.
3) Both solutions also decrease the impact strength of the composites with increased exposure time, with the alkaline solution again having a greater effect.
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A review on techniques and modelling methodologies used for checking electrom...nooriasukmaningtyas
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DEEP LEARNING FOR SMART GRID INTRUSION DETECTION: A HYBRID CNN-LSTM-BASED MODELgerogepatton
As digital technology becomes more deeply embedded in power systems, protecting the communication
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train and test our model. The results of our experiments show that our CNN-LSTM method is much better
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Presentation of IEEE Slovenia CIS (Computational Intelligence Society) Chapte...University of Maribor
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The growing significance of portable systems to limit power consumption in ultra-large-scale-integration chips of very high density, has recently led to rapid and inventive progresses in low-power design. The most effective technique is adiabatic logic circuit design in energy-efficient hardware. This paper presents two adiabatic approaches for the design of low power circuits, modified positive feedback adiabatic logic (modified PFAL) and the other is direct current diode based positive feedback adiabatic logic (DC-DB PFAL). Logic gates are the preliminary components in any digital circuit design. By improving the performance of basic gates, one can improvise the whole system performance. In this paper proposed circuit design of the low power architecture of OR/NOR, AND/NAND, and XOR/XNOR gates are presented using the said approaches and their results are analyzed for powerdissipation, delay, power-delay-product and rise time and compared with the other adiabatic techniques along with the conventional complementary metal oxide semiconductor (CMOS) designs reported in the literature. It has been found that the designs with DC-DB PFAL technique outperform with the percentage improvement of 65% for NOR gate and 7% for NAND gate and 34% for XNOR gate over the modified PFAL techniques at 10 MHz respectively.
Low power architecture of logic gates using adiabatic techniques
Effect of Grain Size and Reaction Time in Characterisation of Aggregates for Alkali Silica Reaction Using Chemical Method
1. R.p Pathak.et al. Int. Journal of Engineering Research and Applications www.ijera.com
ISSN: 2248-9622, Vol. 6, Issue 4, (Part - 1) April 2016, pp.46-52
www.ijera.com 46|P a g e
Effect of Grain Size and Reaction Time in Characterisation of
Aggregates for Alkali Silica Reaction Using Chemical Method
R.P. Pathak1
, Pankaj Sharma2
, Kachhal Prabhaakar3
, Sameer Vyas4
, N.V. Mahure5
,
N Sivakumar 6
1-6
Central Soil and Materials Research Station, Hauz Khas, New Delhi-110016
ABSTRACT
Concrete can deteriorate as a result of alkali aggregate reaction, an interaction between alkalis present in
alkaline pore solution originating from the Portland cement and reactive minerals in certain types of aggregates.
Potential reactivity of aggregates with regard to alkalis present in concrete mix can be determined by Mortar Bar
method, Chemical Method and Petrographic analysis. Of these the chemical method though is quick and does
not require a large quantity of material for testing yet have its own inherent limitations. It does not ensure
completion of reaction as the observations are limited to 24hour only and also does not assess the effect of
varying the combination of coarse and fine aggregates. A study on chemical method by allowing the reaction for
a prolonged time up to 96 hours and also on different grain size ranged matrix was carried at Central Soil and
Materials Research Station, New Delhi. Simultaneously the test results of the modified method are compared to
the existing Mortar Bar method, Chemical Method and Petrographic analysis The outcome of the studies clearly
reflects that the grain size play an important role in the reaction, the reaction time has a demarked impact on
reactivity, in the cases having a high value of silica release the choice of reduction in alkalinity as an indicator
of degree of reaction is not reliable, instead measuring remaining Na2O concentration in Sodium hydroxide
solution after the reaction seems to be much more meaningful in justifying the silica release.
Keywords: Aggregate, Petrographic, Mortar Bar Expansion, Alkali, Silica,
I. INTRODUCTION
Alkali aggregate reaction (AAR) occurs
when there is interaction between the alkalis
present in the pore solution and silicious minerals
in some aggregates forming a calcium alkali
silicate gel(1)
. Potential reactivity of aggregates
with regard to alkalis present in concrete mix can
be determined by chemical method (CM)
developed by Milenz and co-workers of US Bureau
of Reclamation (USBR) in USA(2,3,4)
. For
determining potential reactivity of aggregates CM -
ASTM C 289 -81 and IS 2386 (Pt VII) (5, 6)
are
being followed. These methods cover the chemical
determination of the potential reactivity of an
aggregate with alkalis in a Portland cement
concrete as indicated by the amount of reaction
during 24 hours at 80o
C between 1N NaOH
solution and aggregate that has been crushed and
sieved to pass a 300µm sieve and retained on a
150µm sieve. This chemical method has had a
word wide success, because it is quick, easy to do
and does not require a large quantity of material.
However, it suffers from several defects like
Non Representative Grain Size of Sample
(150µm to 300µm)
The material passing the 150µm sieve is
discarded. The desired fraction is washed. The
reactive silica present in amorphous state in the
aggregates passes
with the fraction smaller than 150µm. Washing of
the desired fraction removes any traces of
amorphous silica.
Abnormality in Measurement of Reduction
in Alkalinity (Rc)
The Reduction in Alkalinity is the
measurement of remaining OH-
ions concentration
after the reaction. The choice of measuring OH ion
concentration is not correct as it is involved in two
reactions. Apart from OH-
ion the HCl titration
using phenolphthalein indicator, is also influenced
by some other anions such as carbonates, silicates,
chlorides and sulphates.
Inadequate Reaction Time
Strained quartz is a slow reacting material,
thus the reaction time of 24 hours is not adequate
to ensure release of total silica content.
Anomaly in Estimation of Nature of
Aggregate in Siliceous Limestone Samples
Siliceous limestone does not show
deleterious nature because of low silica content
compared to the very high CaCO3 level and a very
high Rc because of carbonates.
RESEARCH ARTICLE OPEN ACCESS
2. R.p Pathak.et al. Int. Journal of Engineering Research and Applications www.ijera.com
ISSN: 2248-9622, Vol. 6, Issue 4, (Part - 1) April 2016, pp.46-52
www.ijera.com 47|P a g e
Reappraisal of Chemical Method (Sorentino’s
Kinetic Test Method)
Sorrentino el al(7)
, reappraised the CM by
considering
Grain size of materials (60% of 150µm to
300µm and 40% passing 150µm),
Extension of reaction time upto 96 hrs. and
Reduction in alkalinity
Considering these factors Sorentino’s
Kinetic Test Method (SKT)(8)
was developed and
a new qualification diagram (Fig. 1) for estimation
of nature of aggregate was defined.
Fig. 1 Interpretation Diagram of the Kinetic
Test
The experimental values of silica release
(Sc) and sodium concentration are expressed in the
form of their molar ratio (SiO2/Na2O) as a function
of time. In the new diagram three areas were
assigned for different type of reactivity. The
separation lines have been established on the basis
of field performance record of the materials and /
or on the results of the concentration expansion test
at 380
C for mortar bar test for fine aggregates,
concrete prisms tests for the coarse ones.
A New Approach
SKT with following modifications (NSKT) was
adopted for the present study for characterisation of
the aggregate.
Tests were conducted on samples with
(i) Grain size of materials (150µm to 300µm), as
per CM
(ii) Grain size of materials (60% of 150µm to
300µm and 40% passing 150µm), as per
SKT
(iii) Grain size of materials (passing 150µm),
II. MATERIALS AND METHOD
Six Genesis rock type samples from 3
different hydroelectric projects (Fig. 2) were
selected as detailed in Table 1. These samples were
subjected to petrographic analysis (PA), Mortar Bar
Expansion test (MBE)(9)
and CM as per BIS code,
SKT and NSKT
Fig. 2 Sampling Location
Table 1: Details of collected Aggregate Samples
III. RESULTS AND DISCUSSION
Petrographic Examination
The result of PA is presented in Table-2.
Sample no. 1, 2, 3, 5 and 6 have more than 40% of
strained quartz(10,11)
and angle of Undulatory
Extinction greater than 30o(11).
Mortar Bar Expansion Test
The results of MBE are presented in Table
3. Sample no. 1, 4, 5 and 6 shows more than 0.06%
expansion in six months while sample no. 2 and 3
show expansion less than 0.05%.
Chemical Test
Chemical tests as per CM, SKT and
NSKT methods were performed on all the six
samples. Reduction Rc, Sc, remaining Na2O
concentration in millimoles/litre in 1 N NaOH
solution and ratio of SiO2/Na2O are observed for
each sample. The results are presented in Fig. 3a-
3f, 4a-4f and 5a-5f.
IV. INTERPRETATION OF RESULTS
In PA the potential alkali reactivity of
crystalline rocks is related to the percentage and
straining effects in quartz (Gogte, 1973)(9)
. Rock
aggregate containing 40% or more
strongly undulatory, fractured or highly granulated
quartz are highly reactive; those with 30 to 40%
strained quartz(12)
are moderately reactive while the
ones with predominantly unstrained or
recrystallized quartz are innocuous.
Sl.
No.
Name of Project Rock Type Sampl
e No.
1. Nathpa Jhakri
Power Corporation,
HP
Garnet Mica
Genesis
1
Biotite Genesis 2
2. Kirthai HE Project,
J&K
Quartz Mica
Genesis
3
Genesis
(mylonitised)
4
3. Hirakud Dam
Project, Orissa
Mylonitized
Feldspathic Genesis
5
Genesis
(Feldspathic)
6
3. R.p Pathak.et al. Int. Journal of Engineering Research and Applications www.ijera.com
ISSN: 2248-9622, Vol. 6, Issue 4, (Part - 1) April 2016, pp.46-52
www.ijera.com 48|P a g e
The aggregates showing mortar bar
expansion above 0.05% in six months are classified
as reactive, while those showing lesser expansion
in same period as innocuous (Gogte 1973).
Behaviour of the six aggregate samples as observed
through PA, MBE, CM, SKT and NSKT test
approaches is summarised in Table 4 .
It is noticed that both Rc and Sc values are
increasing with increase in reaction time. The
overall reactivity of different matrices is found to
be in the following order
Sample with grain size matrix
(100% <150 µ) > (60:40 Mixture of 300 - 150µ
& <150 µ ) > (100 % 300 - 150 µ)
V. CONCLUSIONS
Following conclusions can be drawn from
above test results.
1. The grain size play an important role in the
reaction. The fraction less than < 150µ has
shown greater reactivity than other two
fractions. The amorphous silica is generally
lost in the fraction size 300 - 150 µ, hence
showed lowest reactivity. The choice of
fraction containing a mixture of fraction 300 -
150 µ (60%) and fraction < 150µ ( 40% ) is
better to have a representative sample.
2. The reaction time has also impact on
reactivity. As we increase reaction time the
values of reduction in alkalinity and silica
release has generally increase. The aggregates
having good amount of strained quartz have
shown higher reaction values at higher
temperature.
3. Reduction in alkalinity to assess nature of the
aggregate where a high value of silica release
occurs is found to be ill illustrative where as
measuring remaining Na2O concentration in
Sodium hydroxide solution after the reaction
seems to be much more meaningful in
justifying the silica release.
4. R.p Pathak.et al. Int. Journal of Engineering Research and Applications www.ijera.com
ISSN: 2248-9622, Vol. 6, Issue 4, (Part - 1) April 2016, pp.46-52
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Table 2: Result of Petrographic Examination
Sample
No
Mineral Name Quantit
y %
Strained
Quartz %
Angle of Undulatory
Extinction
1 Quartz 30-40 85-90 26-32o
Feldspar 45-50
Biotite 5-7
Muscovite 7-9
Garnet 1-2
2 Quartz 40-45 70-75 26-28o
Feldspar 38-40
Biotite 10-12
Muscovite 4-6
3 Quartz 60-66 40-42 26-28o
Feldspar 18-20
Muscovite 8-10
Biotite 8-10
4 Quartz 52-58 8-10 44-46o
Feldspar 28-30
Muscovite 4-6
Biotite 8-10
5 Quartz 28-30 90-95 38-40o
Feldspar 46-48
Biotite 5-7
Pyroxene 3-4
Chlorite 2-3
Sericite 5-7
Sphene 1-2
Calcite 2-3
Epidote 1-2
6 Quartz 30-35 90-95 38-45o
Feldspar 46-48
Biotite 8-12
Chlorite 2-3
Magnetite 1-2
Sphene 1-2
Calcite 1-2
Table 3: Results of Mortar Bar Expansion Test
Sl.no. Sample No Expansion in % in 6 months
1 1 0.08
2 0.04
2 3 0.04
4 0.06
3 5 0.08
6 0.10
Table 4: Characterisation of Aggregate using Different Tests
I: Innocuous, ID: On border line of Innocuous to Deleterious, D: Deleterious
Sample
No.
PA MBE C
M
SKT NSKT
Time (Hrs) Grain Matrix
< 150 µ (1) 150 µ - 300 µ
(2)
40% of (1) &
60% of (2)
2
4
4
8
7
2
9
6
Time (Hrs.) Time (Hrs.) Time (Hrs.)
2
4
4
8
7
2
9
6
2
4
4
8
7
2
9
6
2
4
4
8
7
2
9
6
1 D D I I I I
D
D I D D D I D D D I I I
D
D
2 D I I I I I D I I
D
D D I D D D I I I D
3 D I I I I I I I I I I I I I I I I I I
4 I D I I I I I I I D D I I D D I I I I
5 D D I I I I
D
D I D D D I D D D I I I
D
D
6 D D I I I I
D
D I D D D I D D D I I I
D
D
5. R.p Pathak.et al. Int. Journal of Engineering Research and Applications www.ijera.com
ISSN: 2248-9622, Vol. 6, Issue 4, (Part - 1) April 2016, pp.46-52
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(a) Sample 1 (b) Sample 2 (c ) Sample 3
(d) Sample 4 (e) Sample 5 (f) Sample 6
Fig. 3 Charactrisation of Aggregate based on Rc
Test on different grain size matrix
6. R.p Pathak.et al. Int. Journal of Engineering Research and Applications www.ijera.com
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(a) Sample 1 (b) Sample 2 (c ) Sample 3
(d) Sample 4 (e) Sample 5 (f) Sample 6
Fig. 4 Charactrisation of Aggregate based on Rc
Test on fraction 150 – 300 µ
7. R.p Pathak.et al. Int. Journal of Engineering Research and Applications www.ijera.com
ISSN: 2248-9622, Vol. 6, Issue 4, (Part - 1) April 2016, pp.46-52
www.ijera.com 52|P a g e
(a) Sample 1 (b) Sample 2 (c ) Sample 3
(d) Sample 4 (e) Sample 5 (f) Sample 6
Fig. 5 Charactrisation of Aggregate based on Rc
Test on fraction 150 – 300 µas a function of
Time
ACKNOWLEDGEMENT
We extend our sincere thanks to Sh. Murari
Ratnam, former Director CSMRS for his guidance.
We extend our sincere gratitude to Sh. Sohan Singh
and Sh. Devender Singh of CSMRS for their
valuable timely help. Sincere gratitude are
extended to all the authors whose publications
provided us directional information from time to
time.
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