The Experts below are selected from a list of 276 Experts worldwide ranked by ideXlab platform
Giedrius Girskas - One of the best experts on this subject based on the ideXlab platform.
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The effect of Synthetic Zeolite on hardened cement paste microstructure and freeze-thaw durability of concrete
Construction and Building Materials, 2017Co-Authors: Giedrius Girskas, Gintautas SkripkiūnasAbstract:Abstract Tests were done with Synthetic Zeolite obtained by synthesizing alumina fluoride production residue, sodium hydroxide and alumina hydroxide. The synthesis lasted for two hours at 95 °C temperature. The obtained product was a mix of Synthetic Zeolite of modifications A and X. The binding material was cement CEM I 42.5R. The test results revealed that substitution of cement with 10% of Synthetic Zeolite reduces water absorption of hardened cement paste ∼23.8%; the addition of air entraining admixture does not change the rate of water absorption. With the increase of Zeolite content in concrete with and without air entraining admixture increases the volume of closed pores from 1.6% to 2.1% and from 4.1% to 7.6% respectively. The open porosity determined by water absorption of concrete with and without air entraining admixture changes insignificantly. The average distance between pores reduces from 360 μm to 190 μm when part of concrete is replaced by Zeolite addition without air entraining admixture and from 190 μm to 130 μm in the case of using air entraining admixture. The addition of 10% of Synthetic Zeolite results in reduced content of portlandite and development of hydro aluminate compounds C 3 AH 6 (cubic crystals) in hardened cement paste. Rose-shaped plates of calcium hydrosulphoaluminates (mono sulphate form) were also detected. These crystals together with hydroaluminates fill in the pores of hardened cement paste and thus reduce the open porosity of concrete. Substitution of 10 wt% of cement with Synthetic Zeolite addition increases the freeze-thaw resistance of concrete, i.e. reduces the loss of surface mass after 28 freeze-thaw cycles more than 1.6 times without the air entraining admixture and up to 3.5 times with air entraining admixture.
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The Effect of Synthetic Zeolite Admixture on the Durability of Concrete Paving Blocks
Baltic Journal of Road and Bridge Engineering, 2016Co-Authors: Giedrius Girskas, Džigita Nagrockienė, Gintautas SkripkiūnasAbstract:Concrete paving blocks that were started to be used in the last century have become very popular. They became an alternative to the natural stone. Concrete paving blocks are used for the paving of pedestrian and vehicle zones. Durability is one of the main characteristics in the production of high-quality concrete paving blocks in the Baltic region climate zone. The article describes tests with concrete paving blocks, the top layer of which contains 5% of Synthetic Zeolite admixture obtained by means of low temperature synthesis in laboratory conditions. This Zeolite admixture is obtained from aluminium fluoride production waste. The durability of concrete paving blocks was tested according to abrasion resistance, tensile splitting strength, absorption and frost resistance. The test results revealed that 5% of Zeolite admixture added to the top layer of concrete paving blocks reduce the absorption, increase the tensile splitting strength by more than 10%, and decrease abrasion by 6.5%. The Zeolite admixture used in concrete paving blocks reduces the scaling about 4 times after 28 freeze-thaw cycles when 3% NaCl is used as the freezing solution. The tests revealed that Synthetic Zeolite admixture can be used in concrete elements production by means of vibropressing (pavement elements) to increase their durability.
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durability of concrete containing Synthetic Zeolite from aluminum fluoride production waste as a supplementary cementitious material
Construction and Building Materials, 2016Co-Authors: Giedrius Girskas, Gintautas Skripkiūnas, Genadijs Sahmenko, Aleksandrs KorjakinsAbstract:Abstract The article analysis the effect of Synthetic Zeolite on properties of concrete mix and hardened concrete. Zeolite was obtained from waste of aluminum fluoride production by low-temperature synthesis and added in concrete mix up to 10% as Portland cement replacing admixture. Test results revealed that, replacing cement by Synthetic Zeolite considerably decreases concrete scaling during freezing and thawing cycles. Compressive strength, density of concrete and water absorption were measured. The test results proved that Synthetic Zeolite obtained from aluminum fluoride by means of low temperature synthesis can be used as a supplementary cementitious material to increase the durability of concrete.
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cement freezing thawing resistance of hardened cement paste with Synthetic Zeolite
Construction and Building Materials, 2014Co-Authors: Dzigita Nagrockiene, Giedrius Girskas, Gintautas SkripkiunasAbstract:Abstract This research article analyzes the Synthetic Zeolite is produced from the waste of AIF3 (amorphous SiO2), NaOH and Al(OH)3 by low-temperature (105 °C) synthesis and modified with CaCl2. The modified Zeolite influence on freeze–thaw and de-icing salt resistance of the hardened cement paste was tested with the replacement of 5% and 10% of the cement mass in the concrete by the Zeolite additive. The specimens with 3% NaCl solution on the top surface were tested by one-sided freeze–thaw cycles. The scaled material content, the elongation of specimens and the ultrasonic pulse velocity were tested after every 7 cycles of freeze–thaw. Internal and surface X-ray diffraction patterns were obtained and analysed. The results of the investigation indicated significant improvement of freeze–thaw and de-icing salt resistance of the hardened cement paste. High freeze–thaw with de-icing salt resistance was obtained by changes in the microstructure of the modified cement paste and cement hydration products. The capillary porosity was reduced and the content of calcium silicate and aluminate hydrates was increased with reduction of Ca(OH)3 content in the hardened cement paste. As a result a denser structure with different morphology of hydration products was obtained in the hardened cement paste with Synthetic Zeolite additive from SEM images. The Synthetic Zeolite can be used as an additive for high freeze–thaw and de-icing salt resistance cement products (concretes, mortars).
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Cement freezing–thawing resistance of hardened cement paste with Synthetic Zeolite
Construction and Building Materials, 2014Co-Authors: Dzigita Nagrockiene, Giedrius Girskas, Gintautas SkripkiunasAbstract:Abstract This research article analyzes the Synthetic Zeolite is produced from the waste of AIF3 (amorphous SiO2), NaOH and Al(OH)3 by low-temperature (105 °C) synthesis and modified with CaCl2. The modified Zeolite influence on freeze–thaw and de-icing salt resistance of the hardened cement paste was tested with the replacement of 5% and 10% of the cement mass in the concrete by the Zeolite additive. The specimens with 3% NaCl solution on the top surface were tested by one-sided freeze–thaw cycles. The scaled material content, the elongation of specimens and the ultrasonic pulse velocity were tested after every 7 cycles of freeze–thaw. Internal and surface X-ray diffraction patterns were obtained and analysed. The results of the investigation indicated significant improvement of freeze–thaw and de-icing salt resistance of the hardened cement paste. High freeze–thaw with de-icing salt resistance was obtained by changes in the microstructure of the modified cement paste and cement hydration products. The capillary porosity was reduced and the content of calcium silicate and aluminate hydrates was increased with reduction of Ca(OH)3 content in the hardened cement paste. As a result a denser structure with different morphology of hydration products was obtained in the hardened cement paste with Synthetic Zeolite additive from SEM images. The Synthetic Zeolite can be used as an additive for high freeze–thaw and de-icing salt resistance cement products (concretes, mortars).
Gintautas Skripkiunas - One of the best experts on this subject based on the ideXlab platform.
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cement freezing thawing resistance of hardened cement paste with Synthetic Zeolite
Construction and Building Materials, 2014Co-Authors: Dzigita Nagrockiene, Giedrius Girskas, Gintautas SkripkiunasAbstract:Abstract This research article analyzes the Synthetic Zeolite is produced from the waste of AIF3 (amorphous SiO2), NaOH and Al(OH)3 by low-temperature (105 °C) synthesis and modified with CaCl2. The modified Zeolite influence on freeze–thaw and de-icing salt resistance of the hardened cement paste was tested with the replacement of 5% and 10% of the cement mass in the concrete by the Zeolite additive. The specimens with 3% NaCl solution on the top surface were tested by one-sided freeze–thaw cycles. The scaled material content, the elongation of specimens and the ultrasonic pulse velocity were tested after every 7 cycles of freeze–thaw. Internal and surface X-ray diffraction patterns were obtained and analysed. The results of the investigation indicated significant improvement of freeze–thaw and de-icing salt resistance of the hardened cement paste. High freeze–thaw with de-icing salt resistance was obtained by changes in the microstructure of the modified cement paste and cement hydration products. The capillary porosity was reduced and the content of calcium silicate and aluminate hydrates was increased with reduction of Ca(OH)3 content in the hardened cement paste. As a result a denser structure with different morphology of hydration products was obtained in the hardened cement paste with Synthetic Zeolite additive from SEM images. The Synthetic Zeolite can be used as an additive for high freeze–thaw and de-icing salt resistance cement products (concretes, mortars).
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Cement freezing–thawing resistance of hardened cement paste with Synthetic Zeolite
Construction and Building Materials, 2014Co-Authors: Dzigita Nagrockiene, Giedrius Girskas, Gintautas SkripkiunasAbstract:Abstract This research article analyzes the Synthetic Zeolite is produced from the waste of AIF3 (amorphous SiO2), NaOH and Al(OH)3 by low-temperature (105 °C) synthesis and modified with CaCl2. The modified Zeolite influence on freeze–thaw and de-icing salt resistance of the hardened cement paste was tested with the replacement of 5% and 10% of the cement mass in the concrete by the Zeolite additive. The specimens with 3% NaCl solution on the top surface were tested by one-sided freeze–thaw cycles. The scaled material content, the elongation of specimens and the ultrasonic pulse velocity were tested after every 7 cycles of freeze–thaw. Internal and surface X-ray diffraction patterns were obtained and analysed. The results of the investigation indicated significant improvement of freeze–thaw and de-icing salt resistance of the hardened cement paste. High freeze–thaw with de-icing salt resistance was obtained by changes in the microstructure of the modified cement paste and cement hydration products. The capillary porosity was reduced and the content of calcium silicate and aluminate hydrates was increased with reduction of Ca(OH)3 content in the hardened cement paste. As a result a denser structure with different morphology of hydration products was obtained in the hardened cement paste with Synthetic Zeolite additive from SEM images. The Synthetic Zeolite can be used as an additive for high freeze–thaw and de-icing salt resistance cement products (concretes, mortars).
Dzigita Nagrockiene - One of the best experts on this subject based on the ideXlab platform.
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cement freezing thawing resistance of hardened cement paste with Synthetic Zeolite
Construction and Building Materials, 2014Co-Authors: Dzigita Nagrockiene, Giedrius Girskas, Gintautas SkripkiunasAbstract:Abstract This research article analyzes the Synthetic Zeolite is produced from the waste of AIF3 (amorphous SiO2), NaOH and Al(OH)3 by low-temperature (105 °C) synthesis and modified with CaCl2. The modified Zeolite influence on freeze–thaw and de-icing salt resistance of the hardened cement paste was tested with the replacement of 5% and 10% of the cement mass in the concrete by the Zeolite additive. The specimens with 3% NaCl solution on the top surface were tested by one-sided freeze–thaw cycles. The scaled material content, the elongation of specimens and the ultrasonic pulse velocity were tested after every 7 cycles of freeze–thaw. Internal and surface X-ray diffraction patterns were obtained and analysed. The results of the investigation indicated significant improvement of freeze–thaw and de-icing salt resistance of the hardened cement paste. High freeze–thaw with de-icing salt resistance was obtained by changes in the microstructure of the modified cement paste and cement hydration products. The capillary porosity was reduced and the content of calcium silicate and aluminate hydrates was increased with reduction of Ca(OH)3 content in the hardened cement paste. As a result a denser structure with different morphology of hydration products was obtained in the hardened cement paste with Synthetic Zeolite additive from SEM images. The Synthetic Zeolite can be used as an additive for high freeze–thaw and de-icing salt resistance cement products (concretes, mortars).
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Cement freezing–thawing resistance of hardened cement paste with Synthetic Zeolite
Construction and Building Materials, 2014Co-Authors: Dzigita Nagrockiene, Giedrius Girskas, Gintautas SkripkiunasAbstract:Abstract This research article analyzes the Synthetic Zeolite is produced from the waste of AIF3 (amorphous SiO2), NaOH and Al(OH)3 by low-temperature (105 °C) synthesis and modified with CaCl2. The modified Zeolite influence on freeze–thaw and de-icing salt resistance of the hardened cement paste was tested with the replacement of 5% and 10% of the cement mass in the concrete by the Zeolite additive. The specimens with 3% NaCl solution on the top surface were tested by one-sided freeze–thaw cycles. The scaled material content, the elongation of specimens and the ultrasonic pulse velocity were tested after every 7 cycles of freeze–thaw. Internal and surface X-ray diffraction patterns were obtained and analysed. The results of the investigation indicated significant improvement of freeze–thaw and de-icing salt resistance of the hardened cement paste. High freeze–thaw with de-icing salt resistance was obtained by changes in the microstructure of the modified cement paste and cement hydration products. The capillary porosity was reduced and the content of calcium silicate and aluminate hydrates was increased with reduction of Ca(OH)3 content in the hardened cement paste. As a result a denser structure with different morphology of hydration products was obtained in the hardened cement paste with Synthetic Zeolite additive from SEM images. The Synthetic Zeolite can be used as an additive for high freeze–thaw and de-icing salt resistance cement products (concretes, mortars).
Gintautas Skripkiūnas - One of the best experts on this subject based on the ideXlab platform.
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The effect of Synthetic Zeolite on hardened cement paste microstructure and freeze-thaw durability of concrete
Construction and Building Materials, 2017Co-Authors: Giedrius Girskas, Gintautas SkripkiūnasAbstract:Abstract Tests were done with Synthetic Zeolite obtained by synthesizing alumina fluoride production residue, sodium hydroxide and alumina hydroxide. The synthesis lasted for two hours at 95 °C temperature. The obtained product was a mix of Synthetic Zeolite of modifications A and X. The binding material was cement CEM I 42.5R. The test results revealed that substitution of cement with 10% of Synthetic Zeolite reduces water absorption of hardened cement paste ∼23.8%; the addition of air entraining admixture does not change the rate of water absorption. With the increase of Zeolite content in concrete with and without air entraining admixture increases the volume of closed pores from 1.6% to 2.1% and from 4.1% to 7.6% respectively. The open porosity determined by water absorption of concrete with and without air entraining admixture changes insignificantly. The average distance between pores reduces from 360 μm to 190 μm when part of concrete is replaced by Zeolite addition without air entraining admixture and from 190 μm to 130 μm in the case of using air entraining admixture. The addition of 10% of Synthetic Zeolite results in reduced content of portlandite and development of hydro aluminate compounds C 3 AH 6 (cubic crystals) in hardened cement paste. Rose-shaped plates of calcium hydrosulphoaluminates (mono sulphate form) were also detected. These crystals together with hydroaluminates fill in the pores of hardened cement paste and thus reduce the open porosity of concrete. Substitution of 10 wt% of cement with Synthetic Zeolite addition increases the freeze-thaw resistance of concrete, i.e. reduces the loss of surface mass after 28 freeze-thaw cycles more than 1.6 times without the air entraining admixture and up to 3.5 times with air entraining admixture.
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The Effect of Synthetic Zeolite Admixture on the Durability of Concrete Paving Blocks
Baltic Journal of Road and Bridge Engineering, 2016Co-Authors: Giedrius Girskas, Džigita Nagrockienė, Gintautas SkripkiūnasAbstract:Concrete paving blocks that were started to be used in the last century have become very popular. They became an alternative to the natural stone. Concrete paving blocks are used for the paving of pedestrian and vehicle zones. Durability is one of the main characteristics in the production of high-quality concrete paving blocks in the Baltic region climate zone. The article describes tests with concrete paving blocks, the top layer of which contains 5% of Synthetic Zeolite admixture obtained by means of low temperature synthesis in laboratory conditions. This Zeolite admixture is obtained from aluminium fluoride production waste. The durability of concrete paving blocks was tested according to abrasion resistance, tensile splitting strength, absorption and frost resistance. The test results revealed that 5% of Zeolite admixture added to the top layer of concrete paving blocks reduce the absorption, increase the tensile splitting strength by more than 10%, and decrease abrasion by 6.5%. The Zeolite admixture used in concrete paving blocks reduces the scaling about 4 times after 28 freeze-thaw cycles when 3% NaCl is used as the freezing solution. The tests revealed that Synthetic Zeolite admixture can be used in concrete elements production by means of vibropressing (pavement elements) to increase their durability.
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durability of concrete containing Synthetic Zeolite from aluminum fluoride production waste as a supplementary cementitious material
Construction and Building Materials, 2016Co-Authors: Giedrius Girskas, Gintautas Skripkiūnas, Genadijs Sahmenko, Aleksandrs KorjakinsAbstract:Abstract The article analysis the effect of Synthetic Zeolite on properties of concrete mix and hardened concrete. Zeolite was obtained from waste of aluminum fluoride production by low-temperature synthesis and added in concrete mix up to 10% as Portland cement replacing admixture. Test results revealed that, replacing cement by Synthetic Zeolite considerably decreases concrete scaling during freezing and thawing cycles. Compressive strength, density of concrete and water absorption were measured. The test results proved that Synthetic Zeolite obtained from aluminum fluoride by means of low temperature synthesis can be used as a supplementary cementitious material to increase the durability of concrete.
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Frost resistance of hardened cement paste modified with Synthetic Zeolite
Engineering Structures and Technologies, 2013Co-Authors: Giedrius Girskas, Džigita Nagrockienė, Gintautas SkripkiūnasAbstract:Abstract The experiment was coducted using Synthetic Zeolite (modification A) obtained in the laboratory of Kaunas University of Technology by means of low-temperature synthesis (below 105 °C). Aluminium fluoride (AIF3) production waste as well as sodium hydroxide NaOH and aluminium hydroxide Al(OH)3were used to obtain a complex Zeolite admixture. SEM analysis revealed that Synthetic Zeolite admixture was made of modification A Zeolite and gypsite. SEM analysis results were confirmed by X-ray analysis. Three batches of specimens were made to determine the effect of Synthetic Zeolite admixture on the durability of hardened cement paste. The first batch was without Synthetic Zeolite admixture, the second batch and the third batch contained 5 wt% and 10 wt% of Synthetic Zeolite admixture, respectively. Synthetic Zeolite admixture was found to have a significant effect on the durability of the hardened cement paste. The weight loss in the hardened cement paste containing 5 wt% of the admixture was three times...
Kaan Yetilmezsoy - One of the best experts on this subject based on the ideXlab platform.
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Production of environmentally friendly cements using Synthetic Zeolite catalyst as the pozzolanic material
Clean Technologies and Environmental Policy, 2019Co-Authors: Edris M. Hassan, Jamil Abdo, Sabah A. Abdul-wahab, Kaan YetilmezsoyAbstract:This study aimed at investigating the effect of addition of varying proportions of Synthetic Zeolite catalyst on the performance of produced cement and subsequently on the reduction of clinker content and the amount of CO_2 emitted to the atmosphere. Mechanical and physical properties represented by compressive strength, fineness, and setting time of five Zeolite-blended cement clinker specimens prepared using different proportions (1–10% by weight) of Synthetic Zeolite catalyst were examined. In addition, reference samples (Synthetic Zeolite-free) were considered to benchmark Synthetic Zeolite-added samples. Compressive strength and setting time tests were conducted for 2, 7, and 28 days of curing to identify mechanical behavior of the cement because of introducing Synthetic Zeolite. Crystal structure, chemical composition, and grain size distribution of samples in micro-areas were also characterized using scanning electron microscopy, energy-dispersive spectrometry, and X-ray diffraction analyses. Observations made in this study indicated that optimum proportions of Synthetic Zeolite could be introduced up to an upper limit of 10% without causing adverse effects on the mechanical behavior, quality, and performance of the produced cement. From the economic point of view, the findings of this study concluded that reduction of CO_2 emission in cement-producing industry and saving in energy consumption could be implicitly achieved as a result of the replacement of the partial cement clinker with Synthetic Zeolite catalyst as the pozzolanic material. The results will be promising to use such additives in cement production to manufacture environmentally sustainable cement.Graphic abstract
