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Guilherme Chagas Cordeiro - One of the best experts on this subject based on the ideXlab platform.

  • improved Pozzolanic Activity of sugar cane bagasse ash by selective grinding and classification
    Cement and Concrete Research, 2016
    Co-Authors: Guilherme Chagas Cordeiro, Luis Marcelo Tavares, R Toledo D Filho
    Abstract:

    Abstract Selective grinding was identified as a potential technology to reduce the content of quartz in sugar cane bagasse ash (SCBA), so as to assist in developing an improved supplementary cementitious material. The selective grinding strategy comprised of a ball mill and two classifiers, where a quartz-rich waste is discharged as a coarse waste by the first one. The amenability of two distinct SCBA samples to selective grinding was first demonstrated on the basis of measurements of strength of individual particles. The samples were then analyzed with respect to chemical and mineralogical compositions and Pozzolanic Activity. Results showed that the quartz content decreased significantly as a result of selective grinding and classification, thus increasing the amorphous content and, consequently, the Pozzolanic Activity for both of the studied SBCA samples. Moreover, good correlations were observed between the amorphous content and SCBA reActivity considering electrical conductivity and Pozzolanic Activity index tests.

  • Pozzolanic Activity of elephant grass ash and its influence on the mechanical properties of concrete
    Cement and Concrete Composites, 2015
    Co-Authors: Guilherme Chagas Cordeiro, Caroline Pessôa Sales
    Abstract:

    Abstract This study was developed to investigate the Pozzolanic Activity of elephant grass ash (EGA) based on different experimental procedures. The production of EGA was performed from three procedures involving the controlled burning of in natura elephant grass and hot water washing and acid leaching pretreatments of grass before calcination. After burning and grinding, a detailed characterization of the ashes based on tests of electrical conductivity, modified Chapelle method and Pozzolanic Activity index was performed to identify the adequate conditions to produce ashes with high silica content and low loss on ignition. In addition, the calcium hydroxide consumption, based on thermal analysis, and the influence of 20% replacement of cement by a particular EGA on the compressive strength, Young’s modulus and water absorption were evaluated. Results indicated that ashes with Pozzolanic properties can be produced from elephant grass. Moreover, the EGA Pozzolanic Activity expressively increases when pretreatments of grass were used, especially acid leaching. Finally, the use of 20% cement replacement promoted no changes in compressive strength of a 35 MPa-concrete up to 28 days of curing.

  • influence of particle size and specific surface area on the Pozzolanic Activity of residual rice husk ash
    Cement & Concrete Composites, 2011
    Co-Authors: Guilherme Chagas Cordeiro, Romildo Dias Toledo Filho, Luis Marcelo Tavares, Eduardo De Moraes Rego Fairbairn, Simone Hempel
    Abstract:

    Abstract The effect of the particle size distribution and specific surface area on the Pozzolanic Activity of a residual rice husk ash (RHA) was investigated in this work. Different samples of RHA obtained from ultrafine grinding were characterized with respect to particle size analyses by laser granulometry, BET and Blaine specific surface areas, pore volume distribution by mercury intrusion porosimetry, surface texture by scanning electron microscopy, Pozzolanic Activity using the cement mortar method and Activity with lime using the Chapelle method. From the results, it was concluded that a good correlation exists between the ‘external’ specific surface area, that is, the surface area associated with the measured particle size distribution, and the Pozzolanic Activity of the residual RHA. On the other hand, nearly no correlation was identified between the Pozzolanic Activity and the specific surface area measured using the BET method, an observation that is particularly related to the cellular nature of the internal structure of this RHA.

  • influence of particle size and specific surface area on the Pozzolanic Activity of residual rice husk ash
    Cement & Concrete Composites, 2011
    Co-Authors: Guilherme Chagas Cordeiro, Romildo Dias Toledo Filho, Luis Marcelo Tavares, Eduardo De Moraes Rego Fairbairn, Simone Hempel
    Abstract:

    Abstract The effect of the particle size distribution and specific surface area on the Pozzolanic Activity of a residual rice husk ash (RHA) was investigated in this work. Different samples of RHA obtained from ultrafine grinding were characterized with respect to particle size analyses by laser granulometry, BET and Blaine specific surface areas, pore volume distribution by mercury intrusion porosimetry, surface texture by scanning electron microscopy, Pozzolanic Activity using the cement mortar method and Activity with lime using the Chapelle method. From the results, it was concluded that a good correlation exists between the ‘external’ specific surface area, that is, the surface area associated with the measured particle size distribution, and the Pozzolanic Activity of the residual RHA. On the other hand, nearly no correlation was identified between the Pozzolanic Activity and the specific surface area measured using the BET method, an observation that is particularly related to the cellular nature of the internal structure of this RHA.

  • Influence of ultrafine wet grinding on Pozzolanic Activity of submicrometre sugar cane bagasse ash
    Advances in Applied Ceramics, 2011
    Co-Authors: Guilherme Chagas Cordeiro, Romildo Dias Toledo Filho, Rs De Almeida
    Abstract:

    Abstract Sugar cane bagasse ash is an important byproduct of sugar and alcohol production. This residual material requires only grinding and classification in order to achieve adequate fineness and homogeneity to be used as Pozzolanic admixture in concrete. In this study, submicrometre ashes were produced from wet grinding using a planetary ball mill. Measurements of the Pozzolanic Activity of the ashes with cement and lime were carried using mechanical methods based on the compressive strength of mortars. It was observed that the Pozzolanic Activity of submicrometre ashes is inversely correlated to its particle size. Moreover, it was demonstrated that the grinding intensity clearly increased the sugar cane bagasse ash reActivity.

Eduardo De Moraes Rego Fairbairn - One of the best experts on this subject based on the ideXlab platform.

  • influence of particle size and specific surface area on the Pozzolanic Activity of residual rice husk ash
    Cement & Concrete Composites, 2011
    Co-Authors: Guilherme Chagas Cordeiro, Romildo Dias Toledo Filho, Luis Marcelo Tavares, Eduardo De Moraes Rego Fairbairn, Simone Hempel
    Abstract:

    Abstract The effect of the particle size distribution and specific surface area on the Pozzolanic Activity of a residual rice husk ash (RHA) was investigated in this work. Different samples of RHA obtained from ultrafine grinding were characterized with respect to particle size analyses by laser granulometry, BET and Blaine specific surface areas, pore volume distribution by mercury intrusion porosimetry, surface texture by scanning electron microscopy, Pozzolanic Activity using the cement mortar method and Activity with lime using the Chapelle method. From the results, it was concluded that a good correlation exists between the ‘external’ specific surface area, that is, the surface area associated with the measured particle size distribution, and the Pozzolanic Activity of the residual RHA. On the other hand, nearly no correlation was identified between the Pozzolanic Activity and the specific surface area measured using the BET method, an observation that is particularly related to the cellular nature of the internal structure of this RHA.

  • influence of particle size and specific surface area on the Pozzolanic Activity of residual rice husk ash
    Cement & Concrete Composites, 2011
    Co-Authors: Guilherme Chagas Cordeiro, Romildo Dias Toledo Filho, Luis Marcelo Tavares, Eduardo De Moraes Rego Fairbairn, Simone Hempel
    Abstract:

    Abstract The effect of the particle size distribution and specific surface area on the Pozzolanic Activity of a residual rice husk ash (RHA) was investigated in this work. Different samples of RHA obtained from ultrafine grinding were characterized with respect to particle size analyses by laser granulometry, BET and Blaine specific surface areas, pore volume distribution by mercury intrusion porosimetry, surface texture by scanning electron microscopy, Pozzolanic Activity using the cement mortar method and Activity with lime using the Chapelle method. From the results, it was concluded that a good correlation exists between the ‘external’ specific surface area, that is, the surface area associated with the measured particle size distribution, and the Pozzolanic Activity of the residual RHA. On the other hand, nearly no correlation was identified between the Pozzolanic Activity and the specific surface area measured using the BET method, an observation that is particularly related to the cellular nature of the internal structure of this RHA.

  • effect of calcination temperature on the Pozzolanic Activity of sugar cane bagasse ash
    Construction and Building Materials, 2009
    Co-Authors: Guilherme Chagas Cordeiro, R Toledo D Filho, Eduardo De Moraes Rego Fairbairn
    Abstract:

    Abstract This work presents the results of the processing of sugar cane bagasse ash (SCBA) under controlled calcination conditions in order to obtain materials with optimum Pozzolanic Activity. Bagasse samples were burnt in an aired electric oven with a heating rate of 10 °C/min, at 350 °C for 3 h, and at different temperatures ranging from 400 to 800 °C for another 3 h. For all calcination temperatures the Pozzolanic Activity, structural state of silica and loss on ignition of the ashes were determined. Moreover, the SCBA with greater Pozzolanicity was characterized by using chemical analysis, scanning electron microscopy, density, specific surface area and chemical reActivity.

Simone Hempel - One of the best experts on this subject based on the ideXlab platform.

  • influence of particle size and specific surface area on the Pozzolanic Activity of residual rice husk ash
    Cement & Concrete Composites, 2011
    Co-Authors: Guilherme Chagas Cordeiro, Romildo Dias Toledo Filho, Luis Marcelo Tavares, Eduardo De Moraes Rego Fairbairn, Simone Hempel
    Abstract:

    Abstract The effect of the particle size distribution and specific surface area on the Pozzolanic Activity of a residual rice husk ash (RHA) was investigated in this work. Different samples of RHA obtained from ultrafine grinding were characterized with respect to particle size analyses by laser granulometry, BET and Blaine specific surface areas, pore volume distribution by mercury intrusion porosimetry, surface texture by scanning electron microscopy, Pozzolanic Activity using the cement mortar method and Activity with lime using the Chapelle method. From the results, it was concluded that a good correlation exists between the ‘external’ specific surface area, that is, the surface area associated with the measured particle size distribution, and the Pozzolanic Activity of the residual RHA. On the other hand, nearly no correlation was identified between the Pozzolanic Activity and the specific surface area measured using the BET method, an observation that is particularly related to the cellular nature of the internal structure of this RHA.

  • influence of particle size and specific surface area on the Pozzolanic Activity of residual rice husk ash
    Cement & Concrete Composites, 2011
    Co-Authors: Guilherme Chagas Cordeiro, Romildo Dias Toledo Filho, Luis Marcelo Tavares, Eduardo De Moraes Rego Fairbairn, Simone Hempel
    Abstract:

    Abstract The effect of the particle size distribution and specific surface area on the Pozzolanic Activity of a residual rice husk ash (RHA) was investigated in this work. Different samples of RHA obtained from ultrafine grinding were characterized with respect to particle size analyses by laser granulometry, BET and Blaine specific surface areas, pore volume distribution by mercury intrusion porosimetry, surface texture by scanning electron microscopy, Pozzolanic Activity using the cement mortar method and Activity with lime using the Chapelle method. From the results, it was concluded that a good correlation exists between the ‘external’ specific surface area, that is, the surface area associated with the measured particle size distribution, and the Pozzolanic Activity of the residual RHA. On the other hand, nearly no correlation was identified between the Pozzolanic Activity and the specific surface area measured using the BET method, an observation that is particularly related to the cellular nature of the internal structure of this RHA.

Luis Marcelo Tavares - One of the best experts on this subject based on the ideXlab platform.

  • improved Pozzolanic Activity of sugar cane bagasse ash by selective grinding and classification
    Cement and Concrete Research, 2016
    Co-Authors: Guilherme Chagas Cordeiro, Luis Marcelo Tavares, R Toledo D Filho
    Abstract:

    Abstract Selective grinding was identified as a potential technology to reduce the content of quartz in sugar cane bagasse ash (SCBA), so as to assist in developing an improved supplementary cementitious material. The selective grinding strategy comprised of a ball mill and two classifiers, where a quartz-rich waste is discharged as a coarse waste by the first one. The amenability of two distinct SCBA samples to selective grinding was first demonstrated on the basis of measurements of strength of individual particles. The samples were then analyzed with respect to chemical and mineralogical compositions and Pozzolanic Activity. Results showed that the quartz content decreased significantly as a result of selective grinding and classification, thus increasing the amorphous content and, consequently, the Pozzolanic Activity for both of the studied SBCA samples. Moreover, good correlations were observed between the amorphous content and SCBA reActivity considering electrical conductivity and Pozzolanic Activity index tests.

  • influence of particle size and specific surface area on the Pozzolanic Activity of residual rice husk ash
    Cement & Concrete Composites, 2011
    Co-Authors: Guilherme Chagas Cordeiro, Romildo Dias Toledo Filho, Luis Marcelo Tavares, Eduardo De Moraes Rego Fairbairn, Simone Hempel
    Abstract:

    Abstract The effect of the particle size distribution and specific surface area on the Pozzolanic Activity of a residual rice husk ash (RHA) was investigated in this work. Different samples of RHA obtained from ultrafine grinding were characterized with respect to particle size analyses by laser granulometry, BET and Blaine specific surface areas, pore volume distribution by mercury intrusion porosimetry, surface texture by scanning electron microscopy, Pozzolanic Activity using the cement mortar method and Activity with lime using the Chapelle method. From the results, it was concluded that a good correlation exists between the ‘external’ specific surface area, that is, the surface area associated with the measured particle size distribution, and the Pozzolanic Activity of the residual RHA. On the other hand, nearly no correlation was identified between the Pozzolanic Activity and the specific surface area measured using the BET method, an observation that is particularly related to the cellular nature of the internal structure of this RHA.

  • influence of particle size and specific surface area on the Pozzolanic Activity of residual rice husk ash
    Cement & Concrete Composites, 2011
    Co-Authors: Guilherme Chagas Cordeiro, Romildo Dias Toledo Filho, Luis Marcelo Tavares, Eduardo De Moraes Rego Fairbairn, Simone Hempel
    Abstract:

    Abstract The effect of the particle size distribution and specific surface area on the Pozzolanic Activity of a residual rice husk ash (RHA) was investigated in this work. Different samples of RHA obtained from ultrafine grinding were characterized with respect to particle size analyses by laser granulometry, BET and Blaine specific surface areas, pore volume distribution by mercury intrusion porosimetry, surface texture by scanning electron microscopy, Pozzolanic Activity using the cement mortar method and Activity with lime using the Chapelle method. From the results, it was concluded that a good correlation exists between the ‘external’ specific surface area, that is, the surface area associated with the measured particle size distribution, and the Pozzolanic Activity of the residual RHA. On the other hand, nearly no correlation was identified between the Pozzolanic Activity and the specific surface area measured using the BET method, an observation that is particularly related to the cellular nature of the internal structure of this RHA.

Romildo Dias Toledo Filho - One of the best experts on this subject based on the ideXlab platform.

  • influence of particle size and specific surface area on the Pozzolanic Activity of residual rice husk ash
    Cement & Concrete Composites, 2011
    Co-Authors: Guilherme Chagas Cordeiro, Romildo Dias Toledo Filho, Luis Marcelo Tavares, Eduardo De Moraes Rego Fairbairn, Simone Hempel
    Abstract:

    Abstract The effect of the particle size distribution and specific surface area on the Pozzolanic Activity of a residual rice husk ash (RHA) was investigated in this work. Different samples of RHA obtained from ultrafine grinding were characterized with respect to particle size analyses by laser granulometry, BET and Blaine specific surface areas, pore volume distribution by mercury intrusion porosimetry, surface texture by scanning electron microscopy, Pozzolanic Activity using the cement mortar method and Activity with lime using the Chapelle method. From the results, it was concluded that a good correlation exists between the ‘external’ specific surface area, that is, the surface area associated with the measured particle size distribution, and the Pozzolanic Activity of the residual RHA. On the other hand, nearly no correlation was identified between the Pozzolanic Activity and the specific surface area measured using the BET method, an observation that is particularly related to the cellular nature of the internal structure of this RHA.

  • influence of particle size and specific surface area on the Pozzolanic Activity of residual rice husk ash
    Cement & Concrete Composites, 2011
    Co-Authors: Guilherme Chagas Cordeiro, Romildo Dias Toledo Filho, Luis Marcelo Tavares, Eduardo De Moraes Rego Fairbairn, Simone Hempel
    Abstract:

    Abstract The effect of the particle size distribution and specific surface area on the Pozzolanic Activity of a residual rice husk ash (RHA) was investigated in this work. Different samples of RHA obtained from ultrafine grinding were characterized with respect to particle size analyses by laser granulometry, BET and Blaine specific surface areas, pore volume distribution by mercury intrusion porosimetry, surface texture by scanning electron microscopy, Pozzolanic Activity using the cement mortar method and Activity with lime using the Chapelle method. From the results, it was concluded that a good correlation exists between the ‘external’ specific surface area, that is, the surface area associated with the measured particle size distribution, and the Pozzolanic Activity of the residual RHA. On the other hand, nearly no correlation was identified between the Pozzolanic Activity and the specific surface area measured using the BET method, an observation that is particularly related to the cellular nature of the internal structure of this RHA.

  • Influence of ultrafine wet grinding on Pozzolanic Activity of submicrometre sugar cane bagasse ash
    Advances in Applied Ceramics, 2011
    Co-Authors: Guilherme Chagas Cordeiro, Romildo Dias Toledo Filho, Rs De Almeida
    Abstract:

    Abstract Sugar cane bagasse ash is an important byproduct of sugar and alcohol production. This residual material requires only grinding and classification in order to achieve adequate fineness and homogeneity to be used as Pozzolanic admixture in concrete. In this study, submicrometre ashes were produced from wet grinding using a planetary ball mill. Measurements of the Pozzolanic Activity of the ashes with cement and lime were carried using mechanical methods based on the compressive strength of mortars. It was observed that the Pozzolanic Activity of submicrometre ashes is inversely correlated to its particle size. Moreover, it was demonstrated that the grinding intensity clearly increased the sugar cane bagasse ash reActivity.