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Gladis Camarini - One of the best experts on this subject based on the ideXlab platform.

  • Pressured recycled Gypsum Plaster and wastes: Characteristics of eco-friendly building components
    2018
    Co-Authors: Rodrigo Henrique Geraldo, Janaina Domingos De Souza, Sofia Cristina De Campos, Luiz Flávio Fernandes, Gladis Camarini
    Abstract:

    Abstract The objective of this paper is to study some characteristics of a component to buildings made with Gypsum Plaster (commercial – CGP and recycled – RGP), and wastes (red ceramic – RC and porcelain – PW) by loading-pressure. Bricks were prepared with a solid mass composition containing 50% (by weight) of binder, 50% (by weight) of waste, and very small water/dried powder ratio (0.22). Specimens were molded with uniaxial loading-pressure (10 kN) before setting times. Compressive and flexural strengths, porosity, and microstructure were evaluated. The compressive results were in the range of 12.3 and 33.9 MPa, higher than the minimum required by Brazilian Standards to building components (≥2.5 MPa). The low water/solid mass ratio and the uniaxial loading-pressure before setting times contribute to decreasing the porosity, which was shown in the dense microstructure. The obtained results show that these components present a good quality building component.

  • Gypsum Plaster waste recycling a potential environmental and industrial solution
    2017
    Co-Authors: Rodrigo Henrique Geraldo, Sayonara M M Pinheiro, Jefferson Santos Da Silva, Heloysa Martins Carvalho Andrade, Jo Dweck, Jardel Pereira Goncalves, Gladis Camarini
    Abstract:

    Abstract Gypsum Plaster waste (GPW) represents a large fraction of the total construction and demolition wastes generated by society, which may contaminate the soil and water resources. Although previous studies have indicated the possibility of recycling GPW, it is not known so far, if the recycling process affects the rehydrated products and how many times the GPW can be recycled without changing its characteristics. The present paper evaluated the properties of recycled Gypsum Plasters produced from a GPW after 1, 3, and 5 recycling cycles, RGP-1, RGP-2, and RGP-3, respectively. The unhydrated and hydrated recycled products were characterized by EDX, XRD, DTA, TG, DTG, as well as by measuring the recycled Plaster setting times and the mechanical properties of respective rehydrated products. The recycling process does not change the Gypsum Plaster chemical composition which is similar to the commercial Gypsum Plaster. Physical properties are changed: bulk density diminished, setting times were shorter due to the change in the grain size with the recycling process. The mechanical performance was good with similar results at longer ages. GPW recyclability has a great potential to be a successful industrial solution and it allows the production of new reusable products, with less negative environmental impacts.

  • effect of wood particle treatment on the properties of Gypsum Plaster pastes and composites
    2016
    Co-Authors: Leandro Shiroma Shiroma, Gladis Camarini, Antonio Ludovico Beraldo
    Abstract:

    In this work the performance of Gypsum Plaster and wood particle in pastes and composites was investigated. Wood particles of fineness 0.42 mm and 1.20 mm were employed. Natural wood particles and the treated ones in cold or hot water (80 °C) were performed. The effects of the extractives solutions from the treatments applied to the wood particles on wood-Gypsum compatibility were studied. For pastes and composites, water-to-Gypsum ratio was 0.65. Wood particles-to-Gypsum Plaster ratios were 5%, 10% and 15%, in mass. Kinetics of temperature, mechanical performance and dynamic elasticity modulus by ultrasound measurements were applied to evaluate the Gypsum Plaster pastes and its composites behaviors. Results show that the extractive solutions changed the time of Gypsum Plaster hydration, being more sensitive to hot water treatment. The composites compressive strength increase with the wood particles pretreatment. The best result was to room temperature treatment. The same performance was found to the modulus of elasticity. Treatments have improved significantly the flexural strength. The best wood particle content was 10%. These results show the possibility of using this wood waste with an easy and simple treatment to make eco-efficient building materials. Keywords: Gypsum Plaster, wood particle, composite, ultrasound, kinetics of temperature.

  • effect of citric acid on properties of recycled Gypsum Plaster to building components
    2016
    Co-Authors: Gladis Camarini, Maria Clara Cavalini Pinto, Aline Goulart De Moura, Natalia Reggiani Manzo
    Abstract:

    Abstract Gypsum Plaster recycling shortens the setting times, changing the workability and becomes difficult to work with it. The works found in literature studied the α-hemi-hydrate. Few works studied the Gypsum Plaster recycling with β-hemihydrate. This experimental work evaluates the performance of recycled Gypsum Plaster with citric acid to improve the setting times and workability to building components. Recycled Gypsum Plaster with five admixture contents was used: 0%; 0.025%; 0.05%; 0.1% and 0.25%. The water/Plaster ratio was kept constant (1.0) for all the mixtures. The results showed that the citric acid decreases the recycled Gypsum Plaster consistency, increasing the fluidity. The setting times were increased, but the compressive strength and hardness were diminished. The microstructure also changed with the admixture addition. Even with these changes in Gypsum Plaster properties, the recycled material can be used to make components because it reaches the minimum values required by the component standards.

  • Gypsum Plaster Waste Recycling: Analysis of Calcination Time
    2015
    Co-Authors: Jaqueline Rosalí De Moraes Rossetto, Lucas Santos Correia, Rodrigo Henrique Geraldo, Gladis Camarini
    Abstract:

    The Gypsum Plaster is a material widely used in constructions around the world. It is a material with high versatility that can be applied from wall coverings to decorative ornaments. However, during its application in buildings, large amounts of waste materials are generated. The average values of waste during its application are higher than 45% of the Gypsum amount used. A series of tests were conducted to develop a feasible methodology to reuse this waste material. The results collected at this stage indicated that it is possible to obtain a recycled product with low energy consumption. It was noted that after a certain number of procedures in which Gypsum was subjected to recycling, there was a loss of workability; however, it did not present relevant changes in mechanical properties. This lack of workability avoids the recycled material maintain its properties in the fresh state as it is subjected to recycling. This work evaluates the calcination time of Gypsum Plaster waste for the production of a Gypsum Plaster with binder properties for using as components. The temperature of calcination was kept constant (150 °C), but the residence time in the stationary kiln was modified. The properties in the powder state (bulk density, fineness modulus, specific mass and sieve analysis), fresh state (mini-slump, setting times and kinetics of temperature) and in the hardened state (compressive strength and hardness) were analysed in order to have some answers about the performance of the recycled Gypsum. In the fresh state, the recycled material showed good results for precast components. The initial setting times were good for all residence times and the final setting times for the material calcined in periods of 5 and 6 hours. In the hardened state, the best compressive strength results were obtained for all residence times, and hardness for calcination for 3, 4, 5 and 6 hours. All these results were satisfactory when compared to the commercial Plaster took as reference. On the other hand, there was a lack of workability in those pastes indicating that an admixture is needed to adjust this property of the recycled material.

Manjit Singh - One of the best experts on this subject based on the ideXlab platform.

  • autoclaved Gypsum Plaster from selenite and by product phosphoGypsum
    2007
    Co-Authors: Manjit Singh, Mohan Rai
    Abstract:

    Investigations were carried out to produce an autoclaved Gypsum Plaster (α-hemihydrate) by heating the naturally occurring selenite and by-product phosphoGypsum under steam pressure in an autoclave. Various factors effecting the calcination of Gypsum such as pressure, time of the autoclaving process and the particle size of Gypsum lumps were investigated. The formation of hemihydrate was examined by periodic differential thermal analysis and weight loss determinations. The mineralogical studies of Plaster were determined using microscopy and X-ray diffraction. The data showed that complete inversion of Gypsum into hemihydrate takes place by heating Gypsum of particle size 15 to 20 mm3 at 1.75 kg cm−2 steam pressure for 7 h. The microscopy of Plaster revealed formation of well-defined euhedral prismatic and tabular shaped crystals showing a higher degree of crystallinity than the conventional β-hemihydrate. The hydraulic properties of Plaster were studied and it was found to possess considerable strength (230 kg cm−2). The α-Plaster has been found suitable for making masonry mortar and fibrous Plaster boards according to the relevant Indian Standards for use in construction works.

  • role of phosphoGypsum impurities on strength and microstructure of selenite Plaster
    2005
    Co-Authors: Manjit Singh
    Abstract:

    Abstract The effect of phosphatic, fluoride and organic impurities as present in waste phosphoGypsum were studied on the setting time, strength development and microstructure of the selenite Gypsum Plaster. The results showed that these impurities affect the physical properties of the Plaster in a similar fashion as observed in the setting and hardening of the phosphoGypsum Plaster. The selenite Plaster sets fast with a fall in strength. The selenite Plaster which normally crystallizes into long interlocking needle shaped crystals has been found to be modified to prismatic, lath, and tabular shaped crystals of variable sizes interspersed with radiating crystals and anhedral to subhedral microcrystallites having irregular boundaries and poor stacking. It is concluded that formation of prismatic and lath-like crystal of different morphology affect the normal setting and strength characteristics of selenite Gypsum Plaster to a great extent. The effect is more pronounced when soluble phosphatic, fluoride and organic matter were added to the selenite Plaster than the sparingly and less soluble compounds intermixed.

  • effect of phosphatic and fluoride impurities of phosphoGypsum on the properties of selenite Plaster
    2003
    Co-Authors: Manjit Singh
    Abstract:

    The effect of phosphatic and fluoride impurities present in waste phosphoGypsum on the setting time, strength development and morphology of selenite Gypsum Plaster have been studied. The results showed that soluble phosphates retard the setting and strength development of Plaster while soluble fluorides decrease the setting time and reduce the density and strength. The Gypsum crystals in the set Plaster are modified from to euhedral to subhedral prismatic, rhombic, tabular and lath-shaped crystals of variable sizes interspersed with subhedral to anhedral needles. It is concluded that the formation of prismatic, rhombic and lathelike crystals retards the normal setting and strength development of selenite Gypsum Plaster.

  • Treating waste phosphoGypsum for cement and Plaster manufacture
    2002
    Co-Authors: Manjit Singh
    Abstract:

    In the investigation reported in this paper, treatment of phosphoGypsum with aqueous citric acid solution was attempted to purify phosphoGypsum and improve its quality to make it fit for manufacture of cement and Gypsum Plaster for the first time. The treatment of Gypsum converts phosphatic and fluoride impurities into water-removable citrates, aluminates and ferrates. The findings of chemical and physical tests and differential thermal analysis of the phosphoGypsum with and without citric acid treatment established improvement of the treatment for purifying phosphoGypsum. The purified phosphoGypsum was found to have lesser amount of impurities of phosphates, fluorides and organic matter than the impure material. The Portland and Portland slag cements produced with purified phosphoGypsum were found to have strength properties similar to those produced from mineral Gypsum, whereas Gypsum Plaster produced conformed to the relevant Indian Standards.

  • retarding action of various chemicals on setting and hardening characteristics of Gypsum Plaster at different ph
    1997
    Co-Authors: Manjit Singh, Mridul Garg
    Abstract:

    Abstract Gypsum Plaster sets quickly due to its natural process of crystallization. For commercial applications, the retardation of Plaster to a desired level is required. The effect of various chemicals as retarders on the setting time, compressive strength and microstructure of the Gypsum Plaster was investigated at pH 4 to 12 adjusted by the addition of Ca(OH)2 or HCl to Gypsum Plaster. It was found that retardation factor has no direct relation with the compressive strength of Gypsum Plaster but pH is certainly related to the strength factor. Maximum compressive strength of the Plaster was obtained at pH 7.0. The morphology of the hardened Gypsum Plaster was found to change according to variation in the pH of the aqueous phase as well as the nature of retarder added.

Aakanksha Pundir - One of the best experts on this subject based on the ideXlab platform.

  • evaluation of properties of Gypsum Plaster superplasticizer blends of improved performance
    2015
    Co-Authors: Aakanksha Pundir, Mridul Garg, Randhir Singh
    Abstract:

    Abstract The effect of SMF-based superplasticizer on the performance of β-hemihydrate Plaster has been studied. A 0.6 wt% SMF content contributes 69% enhancement in the compressive strength of modified paste as compared to reference sample. The influence of superplasticizer on the hydration characteristics and morphology of the Gypsum crystals have been studied by XRD, TGA, SEM and Electrical Conductivity techniques. These studies showed that superplasticizer accelerates the rate of hydration and leads to the formation of a dense and well compacted texture of crystals, thereby imparting high strength and better water resistance to the Gypsum matrix than the reference material.

  • comprehensive study of fly ash binder developed with fly ash alpha Gypsum Plaster portland cement
    2012
    Co-Authors: Mridul Garg, Aakanksha Pundir
    Abstract:

    Abstract In this study, a new type of fly ash binder has been developed using fly ash, hydrated lime sludge and Portland cement, as well as α-Gypsum Plaster as stimulator. The hydration process and microstructure of the fly ash binder was investigated with differential thermal analysis, X-ray diffraction and scanning electron microscopy. These studies showed that the strength development of binder takes place through formation of ettringite and tobermorite. The durability of fly ash binder was assessed by its performance in water by immersion and by alternate wetting and drying cycles at 27–50 °C. The results reveal absence of leaching of the matrix in fly ash binder as well as reduction in strength and enhancement in weight loss with the increase in temperature and cycles. The fly ash binder is found suitable for use in masonry mortars, concrete and bricks.

Mridul Garg - One of the best experts on this subject based on the ideXlab platform.

  • evaluation of properties of Gypsum Plaster superplasticizer blends of improved performance
    2015
    Co-Authors: Aakanksha Pundir, Mridul Garg, Randhir Singh
    Abstract:

    Abstract The effect of SMF-based superplasticizer on the performance of β-hemihydrate Plaster has been studied. A 0.6 wt% SMF content contributes 69% enhancement in the compressive strength of modified paste as compared to reference sample. The influence of superplasticizer on the hydration characteristics and morphology of the Gypsum crystals have been studied by XRD, TGA, SEM and Electrical Conductivity techniques. These studies showed that superplasticizer accelerates the rate of hydration and leads to the formation of a dense and well compacted texture of crystals, thereby imparting high strength and better water resistance to the Gypsum matrix than the reference material.

  • comprehensive study of fly ash binder developed with fly ash alpha Gypsum Plaster portland cement
    2012
    Co-Authors: Mridul Garg, Aakanksha Pundir
    Abstract:

    Abstract In this study, a new type of fly ash binder has been developed using fly ash, hydrated lime sludge and Portland cement, as well as α-Gypsum Plaster as stimulator. The hydration process and microstructure of the fly ash binder was investigated with differential thermal analysis, X-ray diffraction and scanning electron microscopy. These studies showed that the strength development of binder takes place through formation of ettringite and tobermorite. The durability of fly ash binder was assessed by its performance in water by immersion and by alternate wetting and drying cycles at 27–50 °C. The results reveal absence of leaching of the matrix in fly ash binder as well as reduction in strength and enhancement in weight loss with the increase in temperature and cycles. The fly ash binder is found suitable for use in masonry mortars, concrete and bricks.

  • retarding action of various chemicals on setting and hardening characteristics of Gypsum Plaster at different ph
    1997
    Co-Authors: Manjit Singh, Mridul Garg
    Abstract:

    Abstract Gypsum Plaster sets quickly due to its natural process of crystallization. For commercial applications, the retardation of Plaster to a desired level is required. The effect of various chemicals as retarders on the setting time, compressive strength and microstructure of the Gypsum Plaster was investigated at pH 4 to 12 adjusted by the addition of Ca(OH)2 or HCl to Gypsum Plaster. It was found that retardation factor has no direct relation with the compressive strength of Gypsum Plaster but pH is certainly related to the strength factor. Maximum compressive strength of the Plaster was obtained at pH 7.0. The morphology of the hardened Gypsum Plaster was found to change according to variation in the pH of the aqueous phase as well as the nature of retarder added.

Rodrigo Henrique Geraldo - One of the best experts on this subject based on the ideXlab platform.

  • Pressured recycled Gypsum Plaster and wastes: Characteristics of eco-friendly building components
    2018
    Co-Authors: Rodrigo Henrique Geraldo, Janaina Domingos De Souza, Sofia Cristina De Campos, Luiz Flávio Fernandes, Gladis Camarini
    Abstract:

    Abstract The objective of this paper is to study some characteristics of a component to buildings made with Gypsum Plaster (commercial – CGP and recycled – RGP), and wastes (red ceramic – RC and porcelain – PW) by loading-pressure. Bricks were prepared with a solid mass composition containing 50% (by weight) of binder, 50% (by weight) of waste, and very small water/dried powder ratio (0.22). Specimens were molded with uniaxial loading-pressure (10 kN) before setting times. Compressive and flexural strengths, porosity, and microstructure were evaluated. The compressive results were in the range of 12.3 and 33.9 MPa, higher than the minimum required by Brazilian Standards to building components (≥2.5 MPa). The low water/solid mass ratio and the uniaxial loading-pressure before setting times contribute to decreasing the porosity, which was shown in the dense microstructure. The obtained results show that these components present a good quality building component.

  • Gypsum Plaster waste recycling a potential environmental and industrial solution
    2017
    Co-Authors: Rodrigo Henrique Geraldo, Sayonara M M Pinheiro, Jefferson Santos Da Silva, Heloysa Martins Carvalho Andrade, Jo Dweck, Jardel Pereira Goncalves, Gladis Camarini
    Abstract:

    Abstract Gypsum Plaster waste (GPW) represents a large fraction of the total construction and demolition wastes generated by society, which may contaminate the soil and water resources. Although previous studies have indicated the possibility of recycling GPW, it is not known so far, if the recycling process affects the rehydrated products and how many times the GPW can be recycled without changing its characteristics. The present paper evaluated the properties of recycled Gypsum Plasters produced from a GPW after 1, 3, and 5 recycling cycles, RGP-1, RGP-2, and RGP-3, respectively. The unhydrated and hydrated recycled products were characterized by EDX, XRD, DTA, TG, DTG, as well as by measuring the recycled Plaster setting times and the mechanical properties of respective rehydrated products. The recycling process does not change the Gypsum Plaster chemical composition which is similar to the commercial Gypsum Plaster. Physical properties are changed: bulk density diminished, setting times were shorter due to the change in the grain size with the recycling process. The mechanical performance was good with similar results at longer ages. GPW recyclability has a great potential to be a successful industrial solution and it allows the production of new reusable products, with less negative environmental impacts.

  • Gypsum Plaster Waste Recycling: Analysis of Calcination Time
    2015
    Co-Authors: Jaqueline Rosalí De Moraes Rossetto, Lucas Santos Correia, Rodrigo Henrique Geraldo, Gladis Camarini
    Abstract:

    The Gypsum Plaster is a material widely used in constructions around the world. It is a material with high versatility that can be applied from wall coverings to decorative ornaments. However, during its application in buildings, large amounts of waste materials are generated. The average values of waste during its application are higher than 45% of the Gypsum amount used. A series of tests were conducted to develop a feasible methodology to reuse this waste material. The results collected at this stage indicated that it is possible to obtain a recycled product with low energy consumption. It was noted that after a certain number of procedures in which Gypsum was subjected to recycling, there was a loss of workability; however, it did not present relevant changes in mechanical properties. This lack of workability avoids the recycled material maintain its properties in the fresh state as it is subjected to recycling. This work evaluates the calcination time of Gypsum Plaster waste for the production of a Gypsum Plaster with binder properties for using as components. The temperature of calcination was kept constant (150 °C), but the residence time in the stationary kiln was modified. The properties in the powder state (bulk density, fineness modulus, specific mass and sieve analysis), fresh state (mini-slump, setting times and kinetics of temperature) and in the hardened state (compressive strength and hardness) were analysed in order to have some answers about the performance of the recycled Gypsum. In the fresh state, the recycled material showed good results for precast components. The initial setting times were good for all residence times and the final setting times for the material calcined in periods of 5 and 6 hours. In the hardened state, the best compressive strength results were obtained for all residence times, and hardness for calcination for 3, 4, 5 and 6 hours. All these results were satisfactory when compared to the commercial Plaster took as reference. On the other hand, there was a lack of workability in those pastes indicating that an admixture is needed to adjust this property of the recycled material.