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.
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.
Corrosion Inhibition of Carbon Steel in Chloride and Sulfate SolutionsIJERA Editor
Corrosion is a major problem in industry and in infrastructure; a huge sum of expenditure every year is spent on
preventing, retarding, and repairing its damages. This work studies the engineering of an inhibitor for carbon
steel metal used in the cooling systems containing high concentration of chloride and sulfate ions. For this
purpose, the synergy between the dichromate, molybdate and nitrite inhibitors is examined and optimized to the
best results. Moreover, care was taken that the proposed inhibitor is compliant with the environmental laws and
regulations.
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.
Corrosion Inhibition of Carbon Steel in Chloride and Sulfate SolutionsIJERA Editor
Corrosion is a major problem in industry and in infrastructure; a huge sum of expenditure every year is spent on
preventing, retarding, and repairing its damages. This work studies the engineering of an inhibitor for carbon
steel metal used in the cooling systems containing high concentration of chloride and sulfate ions. For this
purpose, the synergy between the dichromate, molybdate and nitrite inhibitors is examined and optimized to the
best results. Moreover, care was taken that the proposed inhibitor is compliant with the environmental laws and
regulations.
Properties of Zinc Phosphate Coatings on Carbon Steel Using a Thermostatic Ce...CrimsonPublishersACSR
Properties of Zinc Phosphate Coatings on Carbon Steel Using a Thermostatic Cell and a Mobile System by Reyes Astivia MJE, Torres JV*, Barrera GM and Díaz CB in Annals of Chemical Science Research
Since the Nobel prize for Physics was awarded to Andre Geim and Konstantin Novoselov “for groundbreaking experiments regarding the two-dimensional material graphene”, the eyes of the scientific world have been focused on this so-called miracle material.
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.
Eco-friendly method for the estimation of cobalt (II) in real samples using 1...Innspub Net
An easy and quick spectrophotometric method is developed for the investigation of cobalt at trace level using 1-(2-Thiazolylazo)-2-naphthol (TAN) in presence of surfactant cetyltrimethylammonium bromide (CTAB) aqueous micellar solution. The cobalt forms bis [1-(2-Thiazolylazo)-2-naphthol] cobalt complex reacting with 1-(2-Thiazolylazo)-2-naphthol. Proposed method is of great importance because use of micellar system instead of solvent extraction steps that were toxic, expensive and time consuming. The method shows improved sensitivity, selectivity and molar absorption. The coefficient of molar absorption and Sandell’s sensitivity was found to be ε 1.89 × 104L mol-1 cm-1 and 3.1ngcm-2 at λmax 572.7nm. Graph of Linear concentration calibration was obtained in the range 0.02-9.0μgmL-1; stoichiometric metal ligand ratio was found 1:2 for the complex Co-[TAN]2 formation. The proposed method was applied for the investigation of cobalt from different alloys, biological, environmental and pharmaceutical samples. Full articles at https://lnkd.in/fbEHTJ6
Combination of urea-Sn+2 in SCP solution was examined as a corrosion inhibitor for concrete reinforced steel by potentiodynamicpolarization, surface synergist parameter and cyclic voltammetry methods comparing with urea–Zn+2 combination. A synergism parameter (SI) indicated a synergistic effect between urea and Sn+2was exist. Polarization study revealed that formulation consisting of 300 ppm urea+50 ppm Sn+2 in SCP solution provided inhibition efficiency (IF) of 85.93% while 300 ppm urea +50 ppm Zn+2 provided 82.3% IF, and this combination acts as anodic type inhibitor. Cyclic voltammetry curves showed that the steel samples immersed in this formulation has low tendency to pitting corrosion. From these results it can be concluded that urea – Sn+2 inhibitor formulation is a good corrosion n inhibitor for concrete reinforced steel, it can maintain stable passive film on steel surface even in the presence of aggressive chloride ions so it can be used instead of the high toxicityZn+2 inhibitor to improve the corrosion inhibition of urea fertilizer inhibitor.
Optimization of iron load in a natural zeolite for heterogeneous catalysisIJRES Journal
A comparative kinetic analysis between surfactant-modified and natural clinoptilolite nanoparticles for benzene removal is presented. The structure and morphology of clinoptilolite crystals with different previous treatments were determined using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The potential of iron sorption, in different metal concentrations, was evaluated by applying Langmuir and Freundlich equations. Experimental results show that Fe (II) loading is higher on clinoptilolite when the zeolite is previously treated with NH4Cl. A cationic surfactant, cetyl trimethylammonium bromide (CTAB), was used to modify the surface of the zeolite loaded with iron. Catalytic and adsorption behavior, for an aqueous benzene solution removal was studied. The inclusion of surfactants in the zeolite structure increases benzene adsorption but reduces their catalytic capacity.
Facile fabrication and characterizations of nanostructured Fe2O3-TiO2 composi...IJAEMSJORNAL
Fe2O3-TiO2 nanoparticles promises as a highly effective material for adsorption of heavy metals and used as photocatalyst for the removal of organic dye pollutants. In this study, nanostructured Fe2O3-TiO2 composite was successfully fabricated by one-step reaction of ilmenite ore at the high temperature in ambient condition. The resultant Fe2O3-TiO2 composite was characterized by using X-ray diffraction (XRD), Fourier Transform Infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), nitrogen adsorption-desorption isotherm. The effects of sintered temperature and time on the formation of the Fe2O3-TiO2 nanocomposite were investigated in detail. The Fe2O3-TiO2 was formed from ilmenite ore after calcination at the temperature of 700oC in 3 hours, followed by a ball-milled process in 4 hours. The obtained Fe2O3-TiO2 composite has an average diameter of from 50 - 100 nm with the BET surface area of 7 m2/g.
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.
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.
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.
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.
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
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
Properties of Zinc Phosphate Coatings on Carbon Steel Using a Thermostatic Ce...CrimsonPublishersACSR
Properties of Zinc Phosphate Coatings on Carbon Steel Using a Thermostatic Cell and a Mobile System by Reyes Astivia MJE, Torres JV*, Barrera GM and Díaz CB in Annals of Chemical Science Research
Since the Nobel prize for Physics was awarded to Andre Geim and Konstantin Novoselov “for groundbreaking experiments regarding the two-dimensional material graphene”, the eyes of the scientific world have been focused on this so-called miracle material.
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.
Eco-friendly method for the estimation of cobalt (II) in real samples using 1...Innspub Net
An easy and quick spectrophotometric method is developed for the investigation of cobalt at trace level using 1-(2-Thiazolylazo)-2-naphthol (TAN) in presence of surfactant cetyltrimethylammonium bromide (CTAB) aqueous micellar solution. The cobalt forms bis [1-(2-Thiazolylazo)-2-naphthol] cobalt complex reacting with 1-(2-Thiazolylazo)-2-naphthol. Proposed method is of great importance because use of micellar system instead of solvent extraction steps that were toxic, expensive and time consuming. The method shows improved sensitivity, selectivity and molar absorption. The coefficient of molar absorption and Sandell’s sensitivity was found to be ε 1.89 × 104L mol-1 cm-1 and 3.1ngcm-2 at λmax 572.7nm. Graph of Linear concentration calibration was obtained in the range 0.02-9.0μgmL-1; stoichiometric metal ligand ratio was found 1:2 for the complex Co-[TAN]2 formation. The proposed method was applied for the investigation of cobalt from different alloys, biological, environmental and pharmaceutical samples. Full articles at https://lnkd.in/fbEHTJ6
Combination of urea-Sn+2 in SCP solution was examined as a corrosion inhibitor for concrete reinforced steel by potentiodynamicpolarization, surface synergist parameter and cyclic voltammetry methods comparing with urea–Zn+2 combination. A synergism parameter (SI) indicated a synergistic effect between urea and Sn+2was exist. Polarization study revealed that formulation consisting of 300 ppm urea+50 ppm Sn+2 in SCP solution provided inhibition efficiency (IF) of 85.93% while 300 ppm urea +50 ppm Zn+2 provided 82.3% IF, and this combination acts as anodic type inhibitor. Cyclic voltammetry curves showed that the steel samples immersed in this formulation has low tendency to pitting corrosion. From these results it can be concluded that urea – Sn+2 inhibitor formulation is a good corrosion n inhibitor for concrete reinforced steel, it can maintain stable passive film on steel surface even in the presence of aggressive chloride ions so it can be used instead of the high toxicityZn+2 inhibitor to improve the corrosion inhibition of urea fertilizer inhibitor.
Optimization of iron load in a natural zeolite for heterogeneous catalysisIJRES Journal
A comparative kinetic analysis between surfactant-modified and natural clinoptilolite nanoparticles for benzene removal is presented. The structure and morphology of clinoptilolite crystals with different previous treatments were determined using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The potential of iron sorption, in different metal concentrations, was evaluated by applying Langmuir and Freundlich equations. Experimental results show that Fe (II) loading is higher on clinoptilolite when the zeolite is previously treated with NH4Cl. A cationic surfactant, cetyl trimethylammonium bromide (CTAB), was used to modify the surface of the zeolite loaded with iron. Catalytic and adsorption behavior, for an aqueous benzene solution removal was studied. The inclusion of surfactants in the zeolite structure increases benzene adsorption but reduces their catalytic capacity.
Facile fabrication and characterizations of nanostructured Fe2O3-TiO2 composi...IJAEMSJORNAL
Fe2O3-TiO2 nanoparticles promises as a highly effective material for adsorption of heavy metals and used as photocatalyst for the removal of organic dye pollutants. In this study, nanostructured Fe2O3-TiO2 composite was successfully fabricated by one-step reaction of ilmenite ore at the high temperature in ambient condition. The resultant Fe2O3-TiO2 composite was characterized by using X-ray diffraction (XRD), Fourier Transform Infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), nitrogen adsorption-desorption isotherm. The effects of sintered temperature and time on the formation of the Fe2O3-TiO2 nanocomposite were investigated in detail. The Fe2O3-TiO2 was formed from ilmenite ore after calcination at the temperature of 700oC in 3 hours, followed by a ball-milled process in 4 hours. The obtained Fe2O3-TiO2 composite has an average diameter of from 50 - 100 nm with the BET surface area of 7 m2/g.
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.
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.
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.
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.
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
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
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
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
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.
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.
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.
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.
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.
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
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
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
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
ScaleUp Partners is a national consultancy helping regions develop community systems that empower underrepresented Americans to compete in a tech-based global innovation economy through a vision, strategy and framework of Inclusive Competitiveness. We help communities achieve equitable access to opportunity, broad productivity a diverse landscape of talented entrepreneurs, improved quality of life for all and shared prosperity throughout the region. Contact us for a free consultation to learn how we can help your region build a more inclusive infrastructure.
Short term properties of High Calcium Flyashbased Geopolymer binderIOSRJMCE
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 of geopolymer from indonesian kaolin and fly ash as a green constru...Pambudi Pajar Pratama
The cement industry is a substantial contributor to the global greenhouse gases emissions, accounting for approximatley 6% of the total global CO2 emission. Geopolymer, an inorganic polymer consisting primarily of Si-Al-O covalent chains, is an attractive alternative to the conventional portland cement due to its much smaller carbon footprint. This research is an early work aimed at elucidating the techno-economic feasibility of geopolymer production in Indonesia, utilizing domestic aluminosilicate minerals and waste materials as feedstocks. Kaolin from the Belitung island and Class F coal fly ash from an electric powerplant in East Java were selected as the geopolymer precursors. The kaolin was initially calcined at 750 oC for 6 hours to convert it to the much more reactive metakaolin phase. Besides the type of aluminosilicate raw materials, the type of alkali solution was also varied between NaOH and KOH. The aluminosilicate materials were each reacted with 10.0 M alkali hydroxide solution at a solid-to-liquid mass ratio of 1.2 and 2.8 for the case of metakaolin and fly ash, respectively. The effect of these variables was evaluated on mortars prepared by using the obtained geopolymers, which involved the measurement of settling time in accordance to an Indonesian standard Vicat apparatus method, and compressive strength according to the ASTM C 109-80 method. The setting time of fly ash - KOH/NaOH geopolymer mortars is shorter than those obtained using metakaolin, due to the higher reactivity of the amorphous fly ash. The higher reactivity of fly ash also promotes better crosslinking of the Si-Al-O bonds, resulting in a higher compressive strength compared to the metakaolin-based geopolymer samples.
Study of Concrete Properties under Acid Attacksijtsrd
Acidic attack on concrete imparts a unique set of damage mechanisms and manifestations compared to other durability issues of concrete. Sulfuric acid attack limits the service life of concrete elements and, thus, results in increased expenditures for the repair or in some cases replacement of the whole structure. To date, there is lack of standardized tests for specifically evaluating the resistance of concrete to sulfuric acid attack, which has caused great variability, for example in terms of solution concentration, pH level control, etc., among previous studies in this area. Accordingly, there are conflicting data about the role of key constituents of concrete e.g. supplementary cementitious materials SCMs , and uncertainty about building codes' stipulations for concrete exposed to sulfuric acid. Hence, the first objective of this thesis was to assess the behaviour of the same concretes, prepared with single and blended binders, to incremental levels mild, severe and very severe of sulfuric acid solutions over 36 weeks. The test variables included the type of cement general use GU or portland limestone cement PLC and SCMs fly ash, silica fume and nano silica . The severe 1 , pH of 1 and very severe aggression 2.5 , pH of 0.5 phases caused mass loss of all specimens, with the latter phase providing clear distinction among the performance of concrete mixtures. The results showed that the penetrability of concrete was not a controlling factor, under severe and very severe damage by sulfuric acid attack, whereas the chemical vulnerability of the binder was the dominant factor. Mixtures prepared from PLC performed better than that of counterparts made from GU. While the quaternary mixtures comprising GU or PLC, fly ash, silica fume and nano silica showed the highest mass losses after 36 weeks, binary mixtures incorporating GU or PLC with fly ash had the lowest mass losses. S. Durgasravanthi | M. Krishna Kumar "Study of Concrete Properties under Acid Attacks" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-5 , August 2019, URL: https://www.ijtsrd.com/papers/ijtsrd26392.pdfPaper URL: https://www.ijtsrd.com/engineering/structural-engineering/26392/study-of-concrete-properties-under-acid-attacks/s-durgasravanthi
Effect Of Curing Temperature And Curing Hours On The Properties Of Geo-Polyme...ijceronline
International Journal of Computational Engineering Research (IJCER) is dedicated to protecting personal information and will make every reasonable effort to handle collected information appropriately. All information collected, as well as related requests, will be handled as carefully and efficiently as possible in accordance with IJCER standards for integrity and objectivity.
Long-term sulfuric and hydrochloric acid resistance of silica fume and colema...Publ 2022
Yurdakul Aygörmez (Main and Corresponding Author)
Yildiz Technical University, Department of Civil Engineering Davutpasa Campus 34220, Esenler, Istanbul (Turkey)
aygormez@yildiz.edu.tr
https://orcid.org/0000-0001-7405-2450
Orhan Canpolat
Yildiz Technical University, Department of Civil Engineering Davutpasa Campus 34220, Esenler, Istanbul (Turkey)
canpolat@yildiz.edu.tr
https://orcid.org/0000-0003-2744-7876
ABSTRACT
For this paper, silica fume (SF), slag (S), and colemanite waste (C) were added to metakaolin (MK)-based geopolymer composites and exposed to 10% (by volume) hydrochloric acid (HCl) and sulfuric acid (H2SO4) solutions for up to 12 months. Geopolymer composites were examined in terms of weight loss, compressive strength, and flexural strength at 3, 6, and 12 months in solutions. Furthermore, Scanning Electron Microscopy (SEM), Microcomputed Tomography (micro-CT), Fourier Transform Infrared Spectroscopy (FTIR), and X-ray Diffraction (XRD) analyses were carried out to examine the microstructure before and after acid attacks. An important decrease in flexural and compressive strengths was seen when geopolymer mortars were subjected to sulfuric and hydrochloric acid attacks. The main cause of this situation is the deterioration of the oxy-aluminum bridge (-Al-Si-O) when exposed to sulfuric and hydrochloric acid. The oxy-aluminum bridge (-Al-Si-O), the primary factor in the geopolymer matrix, plays a significant role in consolidating the gel and enhancing the bond formed between the matrix components. Despite this, geopolymer mortar samples maintain the aluminosilicate structure. Compared to hydrochloric acid, sulfuric acid is a stronger solution, resulting in a greater loss of compressive and flexural strengths.
Cement is the world's most used construction binder material. Cement production emits large amounts of CO2 and consumes significant amount of energy. As a result, it is necessary to find a new concrete material to replace traditional Portland cement concrete, which is environmentally stressful, yet provides an effective building material. Geopolymer is an emerging alternative binder to Portland cement for making concrete. Geopolymer concrete is principally produced by utilizing industrial by-product materials such as fly ash, blast furnace slag, and other aluminosilicate materials. RCC structures undergo serious durability problems like spalling, erosion, wear, cracking, corrosion etc. years after the construction. Repair to damaged concrete are important not only to ensure the planned useful life, but also to provide good performance and security. This paper review the literature related to the studies conducted on geopolymer and repair materials.
Epistemic Interaction - tuning interfaces to provide information for AI supportAlan Dix
Paper presented at SYNERGY workshop at AVI 2024, Genoa, Italy. 3rd June 2024
https://alandix.com/academic/papers/synergy2024-epistemic/
As machine learning integrates deeper into human-computer interactions, the concept of epistemic interaction emerges, aiming to refine these interactions to enhance system adaptability. This approach encourages minor, intentional adjustments in user behaviour to enrich the data available for system learning. This paper introduces epistemic interaction within the context of human-system communication, illustrating how deliberate interaction design can improve system understanding and adaptation. Through concrete examples, we demonstrate the potential of epistemic interaction to significantly advance human-computer interaction by leveraging intuitive human communication strategies to inform system design and functionality, offering a novel pathway for enriching user-system engagements.
Builder.ai Founder Sachin Dev Duggal's Strategic Approach to Create an Innova...Ramesh Iyer
In today's fast-changing business world, Companies that adapt and embrace new ideas often need help to keep up with the competition. However, fostering a culture of innovation takes much work. It takes vision, leadership and willingness to take risks in the right proportion. Sachin Dev Duggal, co-founder of Builder.ai, has perfected the art of this balance, creating a company culture where creativity and growth are nurtured at each stage.
DevOps and Testing slides at DASA ConnectKari Kakkonen
My and Rik Marselis slides at 30.5.2024 DASA Connect conference. We discuss about what is testing, then what is agile testing and finally what is Testing in DevOps. Finally we had lovely workshop with the participants trying to find out different ways to think about quality and testing in different parts of the DevOps infinity loop.
Kubernetes & AI - Beauty and the Beast !?! @KCD Istanbul 2024Tobias Schneck
As AI technology is pushing into IT I was wondering myself, as an “infrastructure container kubernetes guy”, how get this fancy AI technology get managed from an infrastructure operational view? Is it possible to apply our lovely cloud native principals as well? What benefit’s both technologies could bring to each other?
Let me take this questions and provide you a short journey through existing deployment models and use cases for AI software. On practical examples, we discuss what cloud/on-premise strategy we may need for applying it to our own infrastructure to get it to work from an enterprise perspective. I want to give an overview about infrastructure requirements and technologies, what could be beneficial or limiting your AI use cases in an enterprise environment. An interactive Demo will give you some insides, what approaches I got already working for real.
GDG Cloud Southlake #33: Boule & Rebala: Effective AppSec in SDLC using Deplo...James Anderson
Effective Application Security in Software Delivery lifecycle using Deployment Firewall and DBOM
The modern software delivery process (or the CI/CD process) includes many tools, distributed teams, open-source code, and cloud platforms. Constant focus on speed to release software to market, along with the traditional slow and manual security checks has caused gaps in continuous security as an important piece in the software supply chain. Today organizations feel more susceptible to external and internal cyber threats due to the vast attack surface in their applications supply chain and the lack of end-to-end governance and risk management.
The software team must secure its software delivery process to avoid vulnerability and security breaches. This needs to be achieved with existing tool chains and without extensive rework of the delivery processes. This talk will present strategies and techniques for providing visibility into the true risk of the existing vulnerabilities, preventing the introduction of security issues in the software, resolving vulnerabilities in production environments quickly, and capturing the deployment bill of materials (DBOM).
Speakers:
Bob Boule
Robert Boule is a technology enthusiast with PASSION for technology and making things work along with a knack for helping others understand how things work. He comes with around 20 years of solution engineering experience in application security, software continuous delivery, and SaaS platforms. He is known for his dynamic presentations in CI/CD and application security integrated in software delivery lifecycle.
Gopinath Rebala
Gopinath Rebala is the CTO of OpsMx, where he has overall responsibility for the machine learning and data processing architectures for Secure Software Delivery. Gopi also has a strong connection with our customers, leading design and architecture for strategic implementations. Gopi is a frequent speaker and well-known leader in continuous delivery and integrating security into software delivery.
UiPath Test Automation using UiPath Test Suite series, part 3DianaGray10
Welcome to UiPath Test Automation using UiPath Test Suite series part 3. In this session, we will cover desktop automation along with UI automation.
Topics covered:
UI automation Introduction,
UI automation Sample
Desktop automation flow
Pradeep Chinnala, Senior Consultant Automation Developer @WonderBotz and UiPath MVP
Deepak Rai, Automation Practice Lead, Boundaryless Group and UiPath MVP
State of ICS and IoT Cyber Threat Landscape Report 2024 previewPrayukth K V
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1. FOLAGBADE Samuel Olufemi / International Journal of Engineering Research and
Applications (IJERA) ISSN: 2248-9622 www.ijera.com
Vol. 3, Issue 3, May-Jun 2013, pp.582-587
582 | P a g e
Reactivity of cement combinations containing Portland cement,
fly ash, silica fume and metakaolin
FOLAGBADE Samuel Olufemi
Department of Building, Faculty of Environmental Design and Management, Obafemi Awolowo University, Ile-
Ife, 0220005, Nigeria.
ABSTRACT
To examine the reactivity of cement
combination, this paper investigated the
Ca(OH)2 consumption of cement combination
pastes containing Portland cement, fly ash, silica
fume and metakaolin. Pozzolanic reaction is
slow and it would take a long time to complete.
Due to the disparity in their fineness, silica fume
is more reactive than metakaolin and
metakaolin is more reactive than fly ash. The
Ca(OH)2 consumption per unit percentage of the
cement additions reduced with increasing
content with silica fume consuming more than
metakaolin and metakaolin consuming more
than fly ash. The Ca(OH)2 consumption of the
cement additions, increased with increasing age
and increasing fly ash content up to 35%.
Hence, for optimum performance, fly ash as a
binary cement should be limited to 35% content.
Where higher reactivity up to 28 days is
required, silica fume or metakaolin as binary
cement components would perform better at 5%
content than at 10% content. However, beyond
28 days, either 5% or 10% content could be
used as there was no difference in the quantity
of Ca(OH)2 consumed at both levels. The
Ca(OH)2 consumption and reactivity of the
ternary cement pastes is higher than that of the
binary cement pastes. Also, the quantity of
Ca(OH)2 consumed per unit content of the
ternary cements increased with increasing
content up to 10%. 15% would be more than the
optimum content of metakaolin as both binary
or ternary cement component.
Keywords: Blended cement; Ca(OH)2
consumption; cement combination; degree of
hydration; pozzolanic reactivity.
1. Introduction
To reduce cost and make concrete more
environmentally compatible, cement additions such
as silica fume, metakaolin and fly ash are used in
concrete. However, the pozzolanic reactivity of the
cement additions is dependent on the alkalinity of
pore water which is influenced by the quantity of
Ca(OH)2 released by the hydration reaction of
Portland cement.
Due to its availability, low cost and quality control,
fly ash constitutes the primary pozzolana for
majority of blended cements[1]. However, the
pozzolanic reactivity of fly ash is delayed when the
alkalinity of the pore water is low[2]. While this
would result in poor performance at early ages[3,
4,], its improved pozzolanic reactivity with curing
age would produce better performance at later
ages[5]. Finer pozzolanic materials, like silica fume
and metakaolin, would generate more nucleation
sites to accelerate hydration reactions[6]. Hence,
the addition of silica fume would lead to improved
early age performance. The active silica content of
silica fume would accelerate cement hydration[7]
and compensate for the early strength loss and slow
rates of reactions associated with fly ash[8]. Also,
metakaolin would accelerate hydration reaction to
enhance both early and later age strength and
performance of concrete and mortar[9, 10, 11].
Hence, when combined, these cements would play
complimentary roles in concrete performance.
The pozzolanic reactivity and therefore
performance of cement combinations would
depend on the Ca(OH)2 consumption of these
cement additions. While literature permits the use
of silica fume of up to 10%[12, 13], metakaolin of
up to 15%[14] and fly ash of up to 55%[12], data
from the European Ready Mixed Concrete
Organisation[15] show that the cement addition
(majorly GGBS and fly ash) content of the total
cement consumption in ready-mixed concrete was
less than 20%. Hence, in order to examine their
reactivity, this paper investigated the Ca(OH)2
consumption of some binary and ternary cement
combinations within these permitted limits.
2. Experimental materials and cement
combinations
The cements used were Portland cement
(PC, 42.5 type) conforming to BS EN 197- 1,
siliceous or Class F fly ash (FA) conforming to BS
EN 450, silica fume (SF) in a slurry form (50:50
solid/water ratio by weight) conforming to BS EN
13263 and a calcined natural pozzolana
(metakaolin, MK) conforming to BS EN 197- 1.
The properties of the cements are presented in
Table 1.
2. FOLAGBADE Samuel Olufemi / International Journal of Engineering Research and
Applications (IJERA) ISSN: 2248-9622 www.ijera.com
Vol. 3, Issue 3, May-Jun 2013, pp.582-587
583 | P a g e
Table 1: Physical and chemical properties of cements
PROPERTY
CEMENTS
PC FA MK SF
Blaine fineness, m2
/kg 395 388 2588 *
Loss on ignition, % a)
1.9 6.1 b)
0.9 2.7
Particle density, g/cm3
3.17 2.26 2.51 2.17
% retained by 45µm sieve b)
- 11.0 - -
Particle size distribution, cumulative % passing by mass c)
125 µm 100 100 100 100
100 µm 98.2 99.2 100 100
75 µm 93.2 96.5 99.8 100
45 µm 81.8 87.0 99.4 100
25 µm 57.1 66.2 96.0 98.8
10 µm 30.1 40.6 76.2 93.8
5 µm 13.5 24.1 50.7 87.5
2 µm 5.6 10.9 18.2 85.5
1 µm 2.9 4.8 4.7 78.7
0.7 µm 1.3 1.9 1.4 50.7
0.5 µm 0.2 0.3 0.1 10.5
Bulk oxide composition, % d)
CaO 64.5 3.2 0.0 0.4
SiO2 20.0 52.0 57.6 96.6
Al2O3 4.6 26.0 38.9 0.7
Fe2O3 3.7 10.1 0.6 0.2
MgO 2.5 1.5 0.3 0.6
MnO 0.1 0.1 0.0 0.0
TiO2 0.3 1.5 0.0 0.0
K2O 0.7 2.8 2.4 0.8
Na2O 0.3 1.2 0.1 0.3
P2O5 0.1 0.5 0.1 0.1
Cl 0.1 0.0 0.0 0.1
SO3 3.1 1.1 0.0 0.2
* Fineness for SF = 15,000-30,000 m2
/kg[16]
a) In accordance with BS EN 196-2 (except for FA)
b) In accordance with EN 450- 1
c) Obtained with the Laser Particle Sizer
d) Obtained by x-ray fluorescence (XRF)
Potable water, conforming to BS EN 1008, was
used for mixing the paste samples and curing the
paste specimens. The cement combinations (Table
2) were investigated at a free water content of 165
litre/m3
.
3. Experimental method
Cement paste was prepared to BS 196- 3
using a small mixer bowl conforming to BS 196- 1.
The materials were carefully added to water in the
mixer bowl and mixed carefully to avoid the loss of
the materials and ensure thorough mixing and
uniform consistency. Tests were carried out on
hardened specimens of cement pastes at the
water/cement ratios of 0.50 to investigate the
reactivity of the cement combinations. The paste
specimens were cast, cured under a layer of damp
hessian covered with polythene for about 24 hours,
demoulded and cured in water tanks maintained at
about 20o
C until the tests’ dates.
The quantity of Ca(OH)2 consumed at a
particular age was obtained as the difference
between the quantity of Ca(OH)2 present in the
3. FOLAGBADE Samuel Olufemi / International Journal of Engineering Research and
Applications (IJERA) ISSN: 2248-9622 www.ijera.com
Vol. 3, Issue 3, May-Jun 2013, pp.582-587
584 | P a g e
Portland cement paste specimen and the quantity of
Ca(OH)2 present in the other cement paste
specimens at that age. The quantities of Ca(OH)2
present in the cement paste specimens were
determined by thermogravimetric (TG) analysis
which involves measuring the weight loss of a
sample with respect to temperature change. From
the plot of the sample weight against the
temperature, physical and chemical changes that
involve thermal decomposition (or weight loss)
were identified and measured. To avoid weight
gain which could result if the sample reacts with
atmospheric gases, the experiment was conducted
in an inert atmosphere using Nitrogen gas. The TG
equipment also allows constant replacement of its
internal atmosphere in order to flush out the gases
evolved and prevent reactions between the
volatilized substances in the material which could
complicate the interpretation of the
thermogravimetric plots. The TG equipment used is
a STA- 1 installation unit fitted with a 1500o
C
capacity furnace connected to a computer which
automatically log and analyse the data generated.
After crushing the 75mm hardened cement
paste cube into pieces, fragments from its core
were selected, quenched in acetone to stop the
hydration process, oven-dried at 40o
C to avoid
carbonation, cooled to room temperature in a
dessicator containing silica gel and ground into
powder. A minimum powder sample of 10mg was
placed in a platinum crucible, installed on the TG
equipment and heated to a temperature of 1000o
C
at a rate of 10o
C/minute. The TG plot produced was
used to determine the quantity of Ca(OH)2 left in
the samples at the respective ages as stated below.
The % water loss (wL) from the dehydroxylation
region (defined by a temperature range of 400-
500o
C on the graph of the first derivative) was
obtained and used in conjunction with equation 2 to
determine the %Ca(OH)2 content as stated in
equation 1.
%Ca(OH)2 =
18
wL
x 74 (1)
Ca(OH)2 → CaO + H2O (2)
(74g/mole) (56g/mole) (18g/mole)
4 Analysis and discussion of results
The Ca(OH)2 contents and consumption of
the cement pastes, at the curing ages of 28, 90 and
180 days and water/cement ratio of 0.50, are
presented in Table 2. As expected, the quantity of
Ca(OH)2 in the Portland cement paste increases
with increasing curing age. On the other hand, due
to the dilution effect (reduction due to Portland
cement replacement) and the consumption of
Ca(OH)2 by the pozzolanic reactions of the cement
additions, the quantity of Ca(OH)2 in the binary
and ternary cement pastes reduced with increasing
curing age and increasing content of the cement
additions.
Table 2: Hydration properties and Ca(OH)2 consumption of cement combination pastes
MIX COMBINATION
Ca(OH)2 CONTENT AND CONSUMPTION OF CEMENT PASTE,
% Cement Mass
w/c = 0.50
28 DAYS 90 DAYS 180 DAYS
CH1
CH2
CH3
CH1
CH2
CH3
CH1
CH2
CH3
100% PC 22.4 - - 23.3 - - 23.7 - -
80%PC+20%FA 18.2 0.0 0.00 17.2 1.4 0.07 16.5 2.5 0.13
80%PC+15%FA+5%MK 17.5 0.4 0.08 16.5 2.1 0.21 15.8 3.2 0.27
80%PC+15%FA+5%SF 16.7 1.2 0.24 15.8 2.8 0.35 15.2 3.8 0.39
65%PC+35%FA
14.5 0.0 0.00 13.2 1.9 0.05 12.1 3.3 0.09
65%PC+30%FA+5%MK 14.2 0.4 0.06 12.9 2.2 0.11 11.8 3.6 0.15
65%PC+25%FA+10%MK 13.5 1.1 0.10 12.2 2.9 0.15 11.0 4.4 0.20
4. FOLAGBADE Samuel Olufemi / International Journal of Engineering Research and
Applications (IJERA) ISSN: 2248-9622 www.ijera.com
Vol. 3, Issue 3, May-Jun 2013, pp.582-587
585 | P a g e
65%PC+30%FA+5%SF 13.8 0.8 0.14 12.5 2.6 0.19 11.2 4.2 0.27
65%PC+25%FA+10%SF 12.8 1.8 0.17 11.5 3.1 0.22 10.4 5.0 0.26
45%PC+55%FA 10.1 0.0 0.00 9.3 1.2 0.02 8.7 2.0 0.04
45%PC+45%FA+10%MK 9.6 0.5 0.05 8.7 1.8 0.08 8.0 2.7 0.11
45%PC+40%FA+15%MK 9.4 0.7 0.05 8.4 2.1 0.08 7.6 3.1 0.11
45%PC+45%FA+10%SF 9.2 0.9 0.09 8.0 2.5 0.15 7.2 3.5 0.19
95%PC+5%MK 20.1 1.2 0.24 19.2 2.9 0.58 18.5 4.0 0.80
90%PC+10%MK 19.4 0.8 0.08 18.1 2.9 0.29 17.3 4.0 0.40
85%PC+15%MK 18.9 0.1 0.01 17.5 2.3 0.15 16.8 3.3 0.22
95%PC+5%SF 19.2 2.1 0.42 17.8 4.3 0.86 17.0 5.5 1.10
90%PC+10%SF 18.5 1.7 0.17 17.0 4.0 0.40 16.2 5.1 0.51
1) Ca(OH)2 content measured
2) % Ca(OH)2 consumed by additions = (Expected % Ca(OH)2 released by PC minus % Ca(OH)2 content
measured). Expected % Ca(OH)2 released by PC is assumed = 100%PC content x %PC content of mix.
Hence for 80%PC+20%FA,
the expected % Ca(OH)2 released by PC at 90 days would be 23.3 x 0.8 = 18.6 and the % Ca(OH)2
consumed by 80%PC+20%FA at 90 days would be 18.6 – 17.2 = 1.4 as shown on the Table.
3) %Ca(OH)2 consumed per unit percentage of the binary and ternary cement content.
Hence for 80%PC+20%FA at 90 days, %Ca(OH)2 consumed per unit binary cement = 1.4/20 = 0.07 as
shown on the Table. And for 80%PC+15%FA+5%MK at 90 days, %Ca(OH)2 consumed per unit
ternary cement = [ 2.1 - (15 / 20*1.4 )] / 5 = 0.21.
4.1 Ca(OH)2 consumption of binary cements
Though the quantities of Ca(OH)2
consumed by the binary cement pastes increased
with increasing curing age due to pozzolanic
reactivity but they were generally low at 28 days
probably due to the delay in the commencement of
the pozzolanic reaction of the cement additions.
The addition of 20%, 35% and 55% fly ash shows
no consumption of Ca(OH)2 at 28 days. However,
the Ca(OH)2 consumption levels increased
progressively with increasing curing age and were
2.5%, 3.3% and 2.0% respectively at 180 days. The
Ca(OH)2 consumption increased with increasing
content of fly ash from 20-35% and reduced with
increasing content of fly ash from 35-55%. The
latter might be due to the reduced content of
Portland cement (dilution effect), resulting in
Ca(OH)2 content lower than needed for pozzolanic
reaction at that higher contents of fly ash. Hence,
for better reactivity, fly ash content of a fly ash
binary cement combination should not exceed 35%.
Also, the quantity of Ca(OH)2 consumed per unit
percentage of fly ash beyond 28 days increased
with curing age and decreased with increasing
content of fly ash. This might be due to the
reduction in the content of Portland cement
(dilution effect) with increasing content of fly ash.
Silica fume at equal age and replacement level
consumed more Ca(OH)2 than metakaolin. At 28
days, the quantities of Ca(OH)2 consumed by silica
fume and metakaolin, as binary cement
components, increased with increasing curing age
and decreased with increasing content of the
cement additions. Since silica fume binary cement
combinations consumed higher quantities of
Ca(OH)2 than metakaolin binary combinations at
equal replacement level, hence where higher
reactivity for early age performance up to 28 days
is required silica fume would be preferred to
metakaolin and lower content of silica fume or
metakaolin (5% SF or MK) would be preferred to
10% content of silica fume or metakaolin.
Beyond 28 days, while there is little or no
difference in the quantity of Ca(OH)2 consumed at
5% and 10% silica fume content or at 5% and 10%
metakaolin content, the quantities of Ca(OH)2
consumed at 15%MK content were lower than at
10%MK content. While silica fume would
consume more Ca(OH)2 than metakaolin at equal
replacement level, there is no difference between
their performances at 5% or 10% contents. Hence,
the choice of content between 5% and 10% would
depend on other factors like cost and environmental
compatibility. Since the quantities of Ca(OH)2
consumed at 15%MK content were lower than at
10%MK, it shows that 15%MK content might be
more than the optimum content of metakaolin as a
binary cement component.
5. FOLAGBADE Samuel Olufemi / International Journal of Engineering Research and
Applications (IJERA) ISSN: 2248-9622 www.ijera.com
Vol. 3, Issue 3, May-Jun 2013, pp.582-587
586 | P a g e
The quantity of Ca(OH)2 consumed per
unit percentage of silica fume and metakaolin
increased with increasing curing age and reduced
with increasing content of silica fume and
metakaolin. The quantity of Ca(OH)2 consumed per
unit percentage of silica fume and metakaolin were
higher than that of fly ash. This is probably due to
the higher fineness of silica fume and metakaolin,
compared with fly ash, resulting in more nucleation
sites for the pozzolanic reaction with Ca(OH)2. In
the same token, the quantity of Ca(OH)2 consumed
per unit percentage of silica fume is higher than
that of metakaolin at equal replacement level.
The comparison, at 180 days, of the
Ca(OH)2 content of Portland cement and the
Ca(OH)2 consumed by the binary cement pastes
shows that the quantities of Ca(OH)2 consumed by
the binary cement pastes were much lower than the
quantity of Ca(OH)2 released by the hydration
reaction of Portland cement. It could therefore be
inferred that the pozzolanic reaction would be
somehow slow and would take a long time to
complete.
4.2 Ca(OH)2 consumption of ternary
cements
Compared with the fly ash binary cement
pastes, the addition of silica fume and metakaolin
reduced the Ca(OH)2 contents of the pastes with
increasing curing age and increasing content of the
ternary cement. Hence, the addition of silica fume
and metakaolin as ternary cement components
would result in increased consumption of Ca(OH)2
and therefore increased pozzolanic reactivity of the
ternary cement pastes. Also, the quantity of
Ca(OH)2 consumed per unit content of the ternary
cements increased with increasing curing age and
increasing content of the ternary cement component
up to 10%. At the total replacement level of 55%,
the quantity of Ca(OH)2 consumed per unit content
at 10% and 15%MK content were the same at all
the ages. This is probably because the optimum
level of MK at 15%MK must have been exceeded.
Also, the Ca(OH)2 consumed per unit content of
the ternary cement components reduced with
increasing total replacement level of the cement
additions and this would be due to the reduction in
the content of Portland cement with increasing
content of fly ash (dilution effect). Also, silica
fume ternary cement pastes at equal replacement
levels, consumed more Ca(OH)2 than metakaolin
ternary cement pastes. Hence higher pozzolanic
reactivity would be expected in silica fume pastes
than in metakaolin pastes and therefore concretes.
As observed earlier at 180 days, the quantities of
Ca(OH)2 consumed by the ternary cement pastes
were much lower than the quantity of Ca(OH)2
released by the hydration reaction of Portland
cement. This also shows that the pozzolanic
reaction is somehow slow and would take a long
time to complete.
5. Conclusion
As opposed to Portland cement whose
Ca(OH)2 content increased with increasing age, the
Ca(OH)2 contents of the binary and ternary pastes
reduced with increasing curing age and increasing
content of the cement additions due to pozzolanic
reactivity and/or dilution effect due to reduction of
Portland cement by the cement additions. The
Ca(OH)2 consumption and the quantity of Ca(OH)2
consumed per unit percentage of the cement
additions, as binary and ternary cement component,
also increased with increasing age.
The Ca(OH)2 consumption of the cement
additions, as a binary cement component, increased
with increasing fly ash content up to 35%. Hence,
for optimum performance, fly ash as a binary
cement should be limited to 35% content. As
binary cement component, silica fume consumed
more Ca(OH)2 than metakaolin at equal age and
replacement level. Hence, silica fume is more
reactive than metakaolin. Where higher reactivity
up to 28 days is required, silica fume would
perform better than metakaolin. Also silica fume or
metakaolin would perform better at 5% content
than at 10% content. Beyond 28 days, there was no
difference in the quantity of Ca(OH)2 consumed at
5% and 10% contents of silica fume or metakaolin.
Hence, the choice between 5% and 10% content for
silica fume or metakaolin beyond 28 days would
depend on other factors like cost and environmental
compatibility. The quantity of Ca(OH)2 consumed
per unit percentage of the cement additions reduced
with increasing content of the additions with silica
fume consuming more than metakaolin and
metakaolin consuming more than fly ash. As higher
fineness would result in more nucleation sites for
the pozzolanic reaction with Ca(OH)2, this
disparity would be due to the relative difference in
their fineness.
Due to the higher fineness of silica fume
and metakaolin than fly ash, the Ca(OH)2
consumption and reactivity of the ternary cement
pastes is higher than that of the binary cement
pastes. Also, the quantity of Ca(OH)2 consumed
per unit content of the ternary cements increased
with increasing content of the ternary cement
component up to 10%. 15% content of metakaolin
would be more than the optimum content of
metakaolin as a binary or ternary cement
component. Also, the pozzolanic reaction is
somehow slow and would take a long time to
complete.
6. FOLAGBADE Samuel Olufemi / International Journal of Engineering Research and
Applications (IJERA) ISSN: 2248-9622 www.ijera.com
Vol. 3, Issue 3, May-Jun 2013, pp.582-587
587 | P a g e
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