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Yushiro Kihara - One of the best experts on this subject based on the ideXlab platform.
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serra geral formation sao paulo state brazil a potential source for Natural Pozzolans
Materials Letters, 2004Co-Authors: Tarcísio José Montanheiro, Jorge Kazuo Yamamoto, Yushiro KiharaAbstract:Abstract The Serra Geral flood basalts cover an area of approximately 1.2×106 km2, which corresponds to 75% of the Parana Basin. The Serra Geral flood basalt province is one of the largest of the world with a total volume of lava flows exceeding 1.0×106 km3. The Serra Geral Formation comprises a variety of basic (90% of total volume), intermediate (7%) and acid rocks (3%). Intermediate and acid rocks were focused as targets of an exploration program carried out for Natural Pozzolans. In Sao Paulo State, these rocks crop out in the western portion. This paper presents results of a detailed sampling program and laboratory work which led to the identification of potentially pozzolanic rocks. Some of these rocks gave compressive strengths at 7 days between 3 and 6.4 MPa. Besides, for rocks with compressive strengths under 6.0 MPa, the thermal activation was effective improving their pozzolanic properties. Considering these results as well as the area of occurrence, we conclude that intermediate and acid rocks of the Serra Geral Formation in the western portion of Sao Paulo State represent a potential source for Natural Pozzolans.
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Serra Geral Formation—São Paulo State, Brazil: a potential source for Natural Pozzolans
Materials Letters, 2004Co-Authors: Tarcísio José Montanheiro, Jorge Kazuo Yamamoto, Yushiro KiharaAbstract:Abstract The Serra Geral flood basalts cover an area of approximately 1.2×106 km2, which corresponds to 75% of the Parana Basin. The Serra Geral flood basalt province is one of the largest of the world with a total volume of lava flows exceeding 1.0×106 km3. The Serra Geral Formation comprises a variety of basic (90% of total volume), intermediate (7%) and acid rocks (3%). Intermediate and acid rocks were focused as targets of an exploration program carried out for Natural Pozzolans. In Sao Paulo State, these rocks crop out in the western portion. This paper presents results of a detailed sampling program and laboratory work which led to the identification of potentially pozzolanic rocks. Some of these rocks gave compressive strengths at 7 days between 3 and 6.4 MPa. Besides, for rocks with compressive strengths under 6.0 MPa, the thermal activation was effective improving their pozzolanic properties. Considering these results as well as the area of occurrence, we conclude that intermediate and acid rocks of the Serra Geral Formation in the western portion of Sao Paulo State represent a potential source for Natural Pozzolans.
Tarcísio José Montanheiro - One of the best experts on this subject based on the ideXlab platform.
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serra geral formation sao paulo state brazil a potential source for Natural Pozzolans
Materials Letters, 2004Co-Authors: Tarcísio José Montanheiro, Jorge Kazuo Yamamoto, Yushiro KiharaAbstract:Abstract The Serra Geral flood basalts cover an area of approximately 1.2×106 km2, which corresponds to 75% of the Parana Basin. The Serra Geral flood basalt province is one of the largest of the world with a total volume of lava flows exceeding 1.0×106 km3. The Serra Geral Formation comprises a variety of basic (90% of total volume), intermediate (7%) and acid rocks (3%). Intermediate and acid rocks were focused as targets of an exploration program carried out for Natural Pozzolans. In Sao Paulo State, these rocks crop out in the western portion. This paper presents results of a detailed sampling program and laboratory work which led to the identification of potentially pozzolanic rocks. Some of these rocks gave compressive strengths at 7 days between 3 and 6.4 MPa. Besides, for rocks with compressive strengths under 6.0 MPa, the thermal activation was effective improving their pozzolanic properties. Considering these results as well as the area of occurrence, we conclude that intermediate and acid rocks of the Serra Geral Formation in the western portion of Sao Paulo State represent a potential source for Natural Pozzolans.
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Serra Geral Formation—São Paulo State, Brazil: a potential source for Natural Pozzolans
Materials Letters, 2004Co-Authors: Tarcísio José Montanheiro, Jorge Kazuo Yamamoto, Yushiro KiharaAbstract:Abstract The Serra Geral flood basalts cover an area of approximately 1.2×106 km2, which corresponds to 75% of the Parana Basin. The Serra Geral flood basalt province is one of the largest of the world with a total volume of lava flows exceeding 1.0×106 km3. The Serra Geral Formation comprises a variety of basic (90% of total volume), intermediate (7%) and acid rocks (3%). Intermediate and acid rocks were focused as targets of an exploration program carried out for Natural Pozzolans. In Sao Paulo State, these rocks crop out in the western portion. This paper presents results of a detailed sampling program and laboratory work which led to the identification of potentially pozzolanic rocks. Some of these rocks gave compressive strengths at 7 days between 3 and 6.4 MPa. Besides, for rocks with compressive strengths under 6.0 MPa, the thermal activation was effective improving their pozzolanic properties. Considering these results as well as the area of occurrence, we conclude that intermediate and acid rocks of the Serra Geral Formation in the western portion of Sao Paulo State represent a potential source for Natural Pozzolans.
Ali Akbar Ramezanianpour - One of the best experts on this subject based on the ideXlab platform.
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Effect of type, form, and dosage of activators on strength of alkali-activated Natural Pozzolans
Cement and Concrete Composites, 2011Co-Authors: Dali Bondar, Cyril J. Lynsdale, Neil B. Milestone, Nemat Hassani, Ali Akbar RamezanianpourAbstract:Abstract It is possible to synthesize environmentally friendly cementitious construction materials from alkali-activated Natural Pozzolans. The effect of the alkaline medium on the strength of alkali-activated Natural Pozzolans has been investigated and characterised. This paper highlights the effect of the type and form of the alkaline activator, the dosage of alkali and the SiO2/Na2O ratio (silica modulus, Ms) when using water–glass solutions and different curing conditions on the geopolymerisation of Natural Pozzolans. Activation of Natural and calcined pozzolan for production of geopolymeric binder was verified by using Taftan andesite and Shahindej dacite from Iran as a solid precursor. The optimum range for each factor is suggested based on the different effects they have on compressive strength. The concentration of dissolving silicon, aluminium and calcium in alkaline solution, the formation of gel phase and the factors affecting this have been studied by using leaching tests, ICP–AES, and FTIR.
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Effect of heat treatment on reactivity-strength of alkali-activated Natural Pozzolans
Construction and Building Materials, 2011Co-Authors: Dali Bondar, Cyril J. Lynsdale, Neil B. Milestone, Nemat Hassani, Ali Akbar RamezanianpourAbstract:Abstract Natural Pozzolans can be activated and condensed with sodium silicate in an alkaline environment to synthesize high performance cementitious construction materials with low environmental impact. The nature of the starting materials including mineral composition, chemical composition and crystal structure groups affects the formation of the geopolymer gel phase. In this paper, the pozzolanic activities of five Natural Pozzolans are studied. From XRD and XRF results, most of the raw materials contain zeolite clay minerals and have a high loss on ignition. Therefore, before use, samples were calcined at 700, 800 and 900 °C, respectively. The improvement in pozzolanic properties was studied following heat treatment including calcinations and/or elevated curing temperature by using alkali solubility and compressive strength tests. The results show that pozzolan containing sodium zeolite clinoptilolite can be used to prepare a moderate to high strength binder by heat treatment and calcinations can impart disorder hornblende as a constituent of pozzolan with no amorphous phase to prepare a moderate strength binder.
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Engineering Properties of Alkali-Activated Natural Pozzolan Concrete
ACI Materials Journal, 2011Co-Authors: Dali Bondar, Cyril J. Lynsdale, Neil B. Milestone, Nemat Hassani, Ali Akbar RamezanianpourAbstract:The development of alkali-activated binders with superior engineering properties and longer durability has emerged as an alternative to ordinary portland cement (OPC). It is possible to use alkali-activated Natural Pozzolans to prepare environmentally friendly geopolymer cement leading to the concept of sustainable development. This paper presents a summary of an experimental work that was conducted to determine mechanical strength, modulus of elasticity, ultrasonic pulse velocity, and shrinkage of different concrete mixtures prepared with alkali-activated Iranian Natural Pozzolans—namely Taftan andesite and Shahindej dacite, both with and without calcining. Test data were used for Taftan pozzolan to identify the effects of water-binder ratios (w/b) and curing conditions on the properties of the geopolymer concrete, whereas the influence of material composition was studied by activating Shahindej pozzolan both in the Natural and calcined states. The results show that alkali-activated Natural pozzolan (AANP) concretes develop moderate-to-high mechanical strength with a high modulus of elasticity and a shrinkage much lower than with OPC.
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Effect of adding mineral additives to alkali-activated Natural pozzolan paste
Construction and Building Materials, 2011Co-Authors: Dali Bondar, Cyril J. Lynsdale, Neil B. Milestone, Nemat Hassani, Ali Akbar RamezanianpourAbstract:Natural Pozzolans are raw materials from geological deposits with a range of chemical compositions that when combined with suitable alkali activators can be converted to geopolymer cement for concrete production. In this paper the concept of adding mineral additives to enhance the properties of geopolymer cement is introduced. Taftan andesite, a Natural Iranian pozzolan, was used to study the effect of adding mineral additives such as kaolinite, lime and other calcined Pozzolans on the compressive strength of geopolymer cement under both normal and autoclave curing. Scanning electron microscopy (SEM)/energy dispersive X-ray (EDX) was used to determine the composition of the gel phase in both alkali-activated Taftan pozzolan with and without mineral additions. The work has shown that deficiencies in SiO2, Al2O3 and CaO content in the raw Natural pozzolan can be compensated for by adding mineral additives for enhanced properties.
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Effect of Four Iranian Natural Pozzolans on Concrete Durability against Chloride Penetration and Sulfate Attack
2010Co-Authors: Ali Akbar Ramezanianpour, E. Aramun, M. Peidayesh, Peter A. Claisse, E Ganjian, F CanpolatAbstract:Sulfate attacks and chloride corrosion are the most important problems concerning the durability of concrete structures in hot regions of the Persian Gulf and Oman Sea. Natural Pozzolans are Natural mineral admixtures which can improve concrete durability against sulfate attacks and chloride corrosion. This paper presents the results of experimental study on the effect of Natural Pozzolans: Jajrood Truss, Eskandan Pumice, Abyek Tuff, and Khash Pumice, on the ordinary structural concrete durability. Concrete specimens were made of three pozzolan replacement levels, and Rapid Chloride Penetration test, Electrical Resistance test, and Half Cell Potential test were conducted at different ages. In addition, strength reductions and mass changes of concrete specimens immersed in sodium sulfate solution and expansion of concrete prisms immersed in sodium sulfate solution and magnesium sulfate solution were studied. Generally, the results indicate that Natural Pozzolans have positive effects on concrete specimen resistance to the chloride ions penetration and bars corrosion in comparison with concretes containing ordinary cement.
Jorge Kazuo Yamamoto - One of the best experts on this subject based on the ideXlab platform.
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serra geral formation sao paulo state brazil a potential source for Natural Pozzolans
Materials Letters, 2004Co-Authors: Tarcísio José Montanheiro, Jorge Kazuo Yamamoto, Yushiro KiharaAbstract:Abstract The Serra Geral flood basalts cover an area of approximately 1.2×106 km2, which corresponds to 75% of the Parana Basin. The Serra Geral flood basalt province is one of the largest of the world with a total volume of lava flows exceeding 1.0×106 km3. The Serra Geral Formation comprises a variety of basic (90% of total volume), intermediate (7%) and acid rocks (3%). Intermediate and acid rocks were focused as targets of an exploration program carried out for Natural Pozzolans. In Sao Paulo State, these rocks crop out in the western portion. This paper presents results of a detailed sampling program and laboratory work which led to the identification of potentially pozzolanic rocks. Some of these rocks gave compressive strengths at 7 days between 3 and 6.4 MPa. Besides, for rocks with compressive strengths under 6.0 MPa, the thermal activation was effective improving their pozzolanic properties. Considering these results as well as the area of occurrence, we conclude that intermediate and acid rocks of the Serra Geral Formation in the western portion of Sao Paulo State represent a potential source for Natural Pozzolans.
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Serra Geral Formation—São Paulo State, Brazil: a potential source for Natural Pozzolans
Materials Letters, 2004Co-Authors: Tarcísio José Montanheiro, Jorge Kazuo Yamamoto, Yushiro KiharaAbstract:Abstract The Serra Geral flood basalts cover an area of approximately 1.2×106 km2, which corresponds to 75% of the Parana Basin. The Serra Geral flood basalt province is one of the largest of the world with a total volume of lava flows exceeding 1.0×106 km3. The Serra Geral Formation comprises a variety of basic (90% of total volume), intermediate (7%) and acid rocks (3%). Intermediate and acid rocks were focused as targets of an exploration program carried out for Natural Pozzolans. In Sao Paulo State, these rocks crop out in the western portion. This paper presents results of a detailed sampling program and laboratory work which led to the identification of potentially pozzolanic rocks. Some of these rocks gave compressive strengths at 7 days between 3 and 6.4 MPa. Besides, for rocks with compressive strengths under 6.0 MPa, the thermal activation was effective improving their pozzolanic properties. Considering these results as well as the area of occurrence, we conclude that intermediate and acid rocks of the Serra Geral Formation in the western portion of Sao Paulo State represent a potential source for Natural Pozzolans.
Moses Karakouzian - One of the best experts on this subject based on the ideXlab platform.
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pretreatment of Natural perlite powder by further milling to use as a supplementary cementitious material
Construction and Building Materials, 2018Co-Authors: Mahmoud Motahari S Karein, Soroush Isapour, Payam Vosoughi, Moses KarakouzianAbstract:Abstract Replacing a portion of ordinary Portland cement (OPC) with Natural Pozzolans may be an effective solution to reduce the carbon footprint of the concrete industry and construction costs, and to improve concrete durability in general terms. However, some Natural Pozzolans, such as perlite, need to be pretreated to be reactive enough and satisfy the minimum standard qualifications of the concrete industry. This research investigated the effectiveness of milling of Natural perlite as an alternative to calcination, which is the more common reactivation method. For this purpose, the effects of replacing OPC with Natural perlite powder (NPP) were studied at three different levels of fineness and replacement ratios. A variety of tests for the mechanical and transport properties of the concrete were carried out, including a compressive strength test, a surface electrical resistivity test, a water penetration test, a rapid chloride permeability test, and a rapid chloride migration test. These tests conducted on 14 different types of concrete mixtures with various ratios of water-to-cementitious materials (W/Cm), cement content, and replacement ratios. The results demonstrated that increasing the fineness of Natural perlite could be an effective method to reactivate NPP, leading to almost the same compressive strength while improving the transport properties significantly.
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effects of the mechanical milling method on transport properties of self compacting concrete containing perlite powder as a supplementary cementitious material
Construction and Building Materials, 2018Co-Authors: Mahmoud Motahari S Karein, Alireza Joshaghani, A A Ramezanianpour, Soroush Isapour, Moses KarakouzianAbstract:Abstract The purpose of this study is to measure the effects of increasing the specific surface area of perlite Natural pozzolan in self-compacting concrete (SCC) by the mechanical milling method. The use of SCC in construction projects allows for a reduction of human resources and equipment, which significantly decreases the labor cost and time of construction. SCC often needs chemical additives to achieve workability requirements. However, the usage of a greater amount of chemical additives as well as cement materials in the mixing designs increases the cost of mixing. Incorporation of inexpensive Natural Pozzolans as an alternative to cementitious materials can improve the fresh properties and durability of concrete. Moreover, reducing the hydration heat and controlling the shrinkage of SCC mixtures, which mainly contain significant amounts of powdered materials, is another benefit of the Natural Pozzolans. However, the reactivity of Natural Pozzolans, specifically in the early ages, is always a concern when using these supplementary materials. In this study, several methods have been proposed to improve the reactivity of these materials. Increasing the specific surface area of pozzolanic materials by mechanical milling is one of the most economical and efficient methods implemented so far. This study measured the performance of various levels of perlite powder, a Natural pozzolan, for fresh, mechanical and durability properties. In addition, the effects of increasing the specific surface area of perlite powder on properties of concrete were measured and evaluated. According to the results, an increase in the specific surface of perlite powder improved the compressive strength and durability index as a result of increased reactivity. This was accompanied by a substantial improvement in the properties of SCC mixtures in the workability and stability tests.
