Pub Date : 2021-01-01DOI: 10.32047/cwb.2021.26.1.6
L. Xingjun, Y. Duan, Guoqing Chen
In this paper, graphene nanoplatelets [GNPs] in calcium sulfo-aluminate cement-based composites were prepared. The effects of graphene nanoplatelets content and sample thickness on the absorbing properties of composites were studied and the related mechanism was investigated. The experimental results have shown that the sample with a thickness of 25mm exhibited good electromagnetic wave [EMW] absorption, when the content of gra-phene nanoplatelets is 0.06%. The minimum refl ectivity is -30.8 dB at 8.7 GHz, and the cumulative bandwidth [< -5 dB] is 9.5 GHz. When the content of GNPs is increased to 0.08%, the EMW ab-sorption property of the sample does not enhance remarkably. The absorbing property can be improved by adjusting the thickness of sample. The specimen with a thickness of 35 mm performed excellent broadband absorption characteristics.
{"title":"Electromagnetic wave-absorbing properties of graphene nanoplatelets - calcium sulfoaluminate cement - based composites","authors":"L. Xingjun, Y. Duan, Guoqing Chen","doi":"10.32047/cwb.2021.26.1.6","DOIUrl":"https://doi.org/10.32047/cwb.2021.26.1.6","url":null,"abstract":"In this paper, graphene nanoplatelets [GNPs] in calcium sulfo-aluminate cement-based composites were prepared. The effects of graphene nanoplatelets content and sample thickness on the absorbing properties of composites were studied and the related mechanism was investigated. The experimental results have shown that the sample with a thickness of 25mm exhibited good electromagnetic wave [EMW] absorption, when the content of gra-phene nanoplatelets is 0.06%. The minimum refl ectivity is -30.8 dB at 8.7 GHz, and the cumulative bandwidth [< -5 dB] is 9.5 GHz. When the content of GNPs is increased to 0.08%, the EMW ab-sorption property of the sample does not enhance remarkably. The absorbing property can be improved by adjusting the thickness of sample. The specimen with a thickness of 35 mm performed excellent broadband absorption characteristics.","PeriodicalId":55632,"journal":{"name":"Cement Wapno Beton","volume":"53 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90511702","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.32047/cwb.2021.26.2.10
M. Velumani, K. Kumar
In the present study, the effect of copper slag on mechanical properties and durability aspects for Normal Strength Concrete [NSC], High Strength Concrete [HSC] and Ultra-High Strength Concrete [UHSC] mixes have been investigated. Copper slag, which is the by-product discharged from the copper manufacturing industry is replaced by fine aggregate in different proportions. It is observed from the studies that compressive strength has been significantly improved up to 60% replacement of fine aggregate by copper slag for all the mixes. Further, it is noted that even with 100% replace ment of fine aggregate by copper slag, the compressive strength is higher than for the control mix. Durability studies such as rapid chloride penetration test, water sorptivity test and water absorption test showed significant resistance to chloride penetration, sorptivity and water absorption. The reason for significant improvement in compressive strength and durability aspects could be attributed to both pozzolanic activity and filler effect over the cementitious matrix effectively.
{"title":"Effect of copper slag on mechanical and durability aspects for different strength concretes","authors":"M. Velumani, K. Kumar","doi":"10.32047/cwb.2021.26.2.10","DOIUrl":"https://doi.org/10.32047/cwb.2021.26.2.10","url":null,"abstract":"In the present study, the effect of copper slag on mechanical properties and durability aspects for Normal Strength Concrete [NSC], High Strength Concrete [HSC] and Ultra-High Strength Concrete [UHSC] mixes have been investigated. Copper slag, which is the by-product discharged from the copper manufacturing industry is replaced by fine aggregate in different proportions. It is observed from the studies that compressive strength has been significantly improved up to 60% replacement of fine aggregate by copper slag for all the mixes. Further, it is noted that even with 100% replace ment of fine aggregate by copper slag, the compressive strength is higher than for the control mix. Durability studies such as rapid chloride penetration test, water sorptivity test and water absorption test showed significant resistance to chloride penetration, sorptivity and water absorption. The reason for significant improvement in compressive strength and durability aspects could be attributed to both pozzolanic activity and filler effect over the cementitious matrix effectively.","PeriodicalId":55632,"journal":{"name":"Cement Wapno Beton","volume":"55 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82862036","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.32047/cwb.2021.26.2.8
Sebastian Czernik, Mariusz Hynowski, Bartosz Michałowski, J. Michalak, M. Piasecki, J. Tomaszewska
The production of construction products is associated with energy and raw materials consumption, including those of natural origin. Their use is associated with the generation of significant quantity of waste and the emission of greenhouse gases. Therefore, for the sustainable development of civilization, it is essential to reduce the environmental impact of construction products. Gypsum is one of the primary mineral binders, commonly used in construction. The study compares the effect on the environment of building gypsum made of natural raw materials and gypsum obtained in the flue gas desulfurization process. Nine environmental impact indicators were analyzed: global warming potential – GWP, stratospheric ozone layer depletion potential – ODP, soil and water acidification potential – AP, eutrophication potential – EP, tropospheric ozone formation potential – POCP, abiotic depletion potential for non-fossil resources – ADP-elements and fossil resources-ADP-fossil fuels, total use of renewable primary energy resources – PERT and total use of non-renewable primary energy resources – PENRT. Higher values of all considered indicators were obtained for building gypsum made of raw material from flue gas desulfurization processes. The environmental impact assessment was carried out using the Life Cycle Assessment [LCA] method and actual production data from 2017. The life cycle analyzed in this paper covered modules from A1 to A3, i.e., from the extraction/acquisition of raw materials to the finished product, delivered to the factory gate.
{"title":"Analysis of the environmental impact of the production of building gypsum using natural and flue gas desulfurization gypsum in the Polish context","authors":"Sebastian Czernik, Mariusz Hynowski, Bartosz Michałowski, J. Michalak, M. Piasecki, J. Tomaszewska","doi":"10.32047/cwb.2021.26.2.8","DOIUrl":"https://doi.org/10.32047/cwb.2021.26.2.8","url":null,"abstract":"The production of construction products is associated with energy and raw materials consumption, including those of natural origin. Their use is associated with the generation of significant quantity of waste and the emission of greenhouse gases. Therefore, for the sustainable development of civilization, it is essential to reduce the environmental impact of construction products. Gypsum is one of the primary mineral binders, commonly used in construction. The study compares the effect on the environment of building gypsum made of natural raw materials and gypsum obtained in the flue gas desulfurization process. Nine environmental impact indicators were analyzed: global warming potential – GWP, stratospheric ozone layer depletion potential – ODP, soil and water acidification potential – AP, eutrophication potential – EP, tropospheric ozone formation potential – POCP, abiotic depletion potential for non-fossil resources – ADP-elements and fossil resources-ADP-fossil fuels, total use of renewable primary energy resources – PERT and total use of non-renewable primary energy resources – PENRT. Higher values of all considered indicators were obtained for building gypsum made of raw material from flue gas desulfurization processes. The environmental impact assessment was carried out using the Life Cycle Assessment [LCA] method and actual production data from 2017. The life cycle analyzed in this paper covered modules from A1 to A3, i.e., from the extraction/acquisition of raw materials to the finished product, delivered to the factory gate.","PeriodicalId":55632,"journal":{"name":"Cement Wapno Beton","volume":"63 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89548652","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.32047/cwb.2021.26.6.4
A. R. Krishnaraja, M. Harihanandh, S. Anandakumar
In this study, an effort was taken to progress the performance of Engineered Cementitious Composites [ECC] mix, by incorporating two different fibers. Five different proportions were subjected to investigation, in this three different proportions were developed with single fiber with 2.0% volume fraction, other two proportions were with two types of fibers. Hybrid ECC proportions were organized through the mixture of low-modulusfibers [poly(vinyl alcohol) fiber] and high-modulus fibers [steel and glassfibers]. Three proportions were made with metallic, glassfiber and poly vinyl alcohol fiber. The hybridation proportions were made with a 2/3 fraction of poly vinyl alcohol fiber and 1/3 fraction of the metal fiber in 2.0% of volume fraction and accompanied with poly vinyl alcoholfiber 2/3 fraction and 1/3 fraction of glass fiber. This procedure has a good rate of success in tensile and bending behavior of ECC mix. From this effort, it was concluded that poly(vinyl alcohol) fiber 2/3 fraction and 1/3 fraction of glass fiber in 2.0% volume fraction, displayed reasonable traits.
{"title":"Mechanical performance of engineered cementitious composites developed with different modulus fibers","authors":"A. R. Krishnaraja, M. Harihanandh, S. Anandakumar","doi":"10.32047/cwb.2021.26.6.4","DOIUrl":"https://doi.org/10.32047/cwb.2021.26.6.4","url":null,"abstract":"In this study, an effort was taken to progress the performance of Engineered Cementitious Composites [ECC] mix, by incorporating two different fibers. Five different proportions were subjected to investigation, in this three different proportions were developed with single fiber with 2.0% volume fraction, other two proportions were with two types of fibers. Hybrid ECC proportions were organized through the mixture of low-modulusfibers [poly(vinyl alcohol) fiber] and high-modulus fibers [steel and glassfibers]. Three proportions were made with metallic, glassfiber and poly vinyl alcohol fiber. The hybridation proportions were made with a 2/3 fraction of poly vinyl alcohol fiber and 1/3 fraction of the metal fiber in 2.0% of volume fraction and accompanied with poly vinyl alcoholfiber 2/3 fraction and 1/3 fraction of glass fiber. This procedure has a good rate of success in tensile and bending behavior of ECC mix. From this effort, it was concluded that poly(vinyl alcohol) fiber 2/3 fraction and 1/3 fraction of glass fiber in 2.0% volume fraction, displayed reasonable traits.","PeriodicalId":55632,"journal":{"name":"Cement Wapno Beton","volume":"1 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91044044","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.32047/cwb.2021.26.3.4
Majid Safamehr, M. Izadinia, S. Hashemi, Saeideh Koohestani
Two families of heavy concrete were investigated in this project, the first containing hematite and the second magnetite aggregates. Boron carbide also replaced cement in mass of 2.5, 5 and 10%. Once again, in these compounds the content of cement was reduced by 5% and replaced by nanosilica. Such parameters as compressive strength, ultrasonic pulse velocity and density were investigated, and the specimens were irradiated with cobalt 60, to quantify the linear attenuation coefficient. Using iron ore aggregate, especially magnetite, was advantageous for all the above-mentioned parameters, while the opposite was true, when boron carbide was added to the mix. The addition of nanosilica compensated the decrease in compressive strength of concrete due to the presence of boron carbide, but reduced the linear attenuation coefficient by about 4%. However, the properties of the mixes containing boron carbide and nanosilica, were always better than those of conventional concretes. To quantify the linear attenuation coefficient, Monte Carlo simulations were performed, and their results turned out to be in good agreement with those obtained by the experimental measurements.
{"title":"Nanosilica role in concrete containing iron oxides aggregates and boron carbide as a shield against gamma rays","authors":"Majid Safamehr, M. Izadinia, S. Hashemi, Saeideh Koohestani","doi":"10.32047/cwb.2021.26.3.4","DOIUrl":"https://doi.org/10.32047/cwb.2021.26.3.4","url":null,"abstract":"Two families of heavy concrete were investigated in this project, the first containing hematite and the second magnetite aggregates. Boron carbide also replaced cement in mass of 2.5, 5 and 10%. Once again, in these compounds the content of cement was reduced by 5% and replaced by nanosilica. Such parameters as compressive strength, ultrasonic pulse velocity and density were investigated, and the specimens were irradiated with cobalt 60, to quantify the linear attenuation coefficient. Using iron ore aggregate, especially magnetite, was advantageous for all the above-mentioned parameters, while the opposite was true, when boron carbide was added to the mix. The addition of nanosilica compensated the decrease in compressive strength of concrete due to the presence of boron carbide, but reduced the linear attenuation coefficient by about 4%. However, the properties of the mixes containing boron carbide and nanosilica, were always better than those of conventional concretes. To quantify the linear attenuation coefficient, Monte Carlo simulations were performed, and their results turned out to be in good agreement with those obtained by the experimental measurements.","PeriodicalId":55632,"journal":{"name":"Cement Wapno Beton","volume":"3 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87731057","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.32047/cwb.2021.26.6.5
Majid Safamehr, M. Izadinia, Seyed Hamid Hashemi, Seyed Jalil Hoseini
The ability to create various compounds has made concrete one of the most suitable materials for constructing radiation shields. In this investigation, hematite and magnetite aggregates were used to replace ordinary aggregate, separately and completely in two stages. Boron carbide was also substituting cement at percentages of 2.5, 5, and 10 by mass. The density test, gamma irradiation with Co 60 and neutron irradiation with Am-Be 241 were performed. According to the results, the replacement of ordinary aggregates with hematite aggregates in concrete, improved the linear attenuation coefficient and macroscopic cross section by 17% and 73%, respectively. These parameters increased by 37% and 105%, respectively, by the use of magnetite aggregates. Moreover, with the addition of a maximum of 10% boron carbide to the concrete, the macroscopic cross-section increased by 120%, however, the linear attenuation coefficient decreased by between 5% and 8%. This means that it is possible to have a suitable attenuation of gamma ray and neutron beams in a single layer of concrete shield simultaneously. In addition, the results of the tests and Monte Carlo simulation were found to have good consistency.
{"title":"Simultaneous attenuation of gamma ray and neutrons in single layer concrete shield","authors":"Majid Safamehr, M. Izadinia, Seyed Hamid Hashemi, Seyed Jalil Hoseini","doi":"10.32047/cwb.2021.26.6.5","DOIUrl":"https://doi.org/10.32047/cwb.2021.26.6.5","url":null,"abstract":"The ability to create various compounds has made concrete one of the most suitable materials for constructing radiation shields. In this investigation, hematite and magnetite aggregates were used to replace ordinary aggregate, separately and completely in two stages. Boron carbide was also substituting cement at percentages of 2.5, 5, and 10 by mass. The density test, gamma irradiation with Co 60 and neutron irradiation with Am-Be 241 were performed. According to the results, the replacement of ordinary aggregates with hematite aggregates in concrete, improved the linear attenuation coefficient and macroscopic cross section by 17% and 73%, respectively. These parameters increased by 37% and 105%, respectively, by the use of magnetite aggregates. Moreover, with the addition of a maximum of 10% boron carbide to the concrete, the macroscopic cross-section increased by 120%, however, the linear attenuation coefficient decreased by between 5% and 8%. This means that it is possible to have a suitable attenuation of gamma ray and neutron beams in a single layer of concrete shield simultaneously. In addition, the results of the tests and Monte Carlo simulation were found to have good consistency.","PeriodicalId":55632,"journal":{"name":"Cement Wapno Beton","volume":"41 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75437520","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.32047/cwb.2021.26.1.1
B. Sumanth Kumar, D. Rama Seshu
Geopolymer concrete is the composite and has prospective potential to become one of the alternatives to conventional concrete. This paper presents an experimental investigation on the shear strength of monolithic geopolymer concrete interface. A total of 18 push-off specimens with and without reinforcement across the interface were cast and tested. The experimental shear strength of geopolymer concrete is compared with the shear strength evaluated, using the available analytical models for normal concrete. The test results indicated that the shear strength of monolithic geopolymer concrete interface has increased up to certain compression strength of geopolymer concrete. Most of the available analytical models are conservative in estimating the shear strength of geopolymer concrete.
{"title":"A comparative study of shear strength of monolithic geopolymer concrete interface","authors":"B. Sumanth Kumar, D. Rama Seshu","doi":"10.32047/cwb.2021.26.1.1","DOIUrl":"https://doi.org/10.32047/cwb.2021.26.1.1","url":null,"abstract":"Geopolymer concrete is the composite and has prospective potential to become one of the alternatives to conventional concrete. This paper presents an experimental investigation on the shear strength of monolithic geopolymer concrete interface. A total of 18 push-off specimens with and without reinforcement across the interface were cast and tested. The experimental shear strength of geopolymer concrete is compared with the shear strength evaluated, using the available analytical models for normal concrete. The test results indicated that the shear strength of monolithic geopolymer concrete interface has increased up to certain compression strength of geopolymer concrete. Most of the available analytical models are conservative in estimating the shear strength of geopolymer concrete.","PeriodicalId":55632,"journal":{"name":"Cement Wapno Beton","volume":"1 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77782744","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.32047/cwb.2021.26.5.4
J. Smoleń, Berk Değirmenci, Berke Doğuş Tekeli, Bartłomiej Nowacki
In this paper, the production of aggregate from car windshield cullet and the use of this aggregate, in various compositions with fine quartz sand, as the reinforcing phase of the epoxy matrix polymer concrete were used and the obtained samples were tested. The bending and compressive strength, Charpy’s impact resistance tests were performed on the obtained composites. The porosity, water absorption, and density were also determined. The tests performed have shown that the application of car windshield cullet in polymer concrete, seems to be a good way to recycle this waste. The highest compressive strength, equal to 101 MPa, was obtained by composites containing 20 vol% of milled glass. It is nearly 7 times higher than the value of traditional concrete tested simultaneously, which has about 15 MPa. The highest flexural strength was noted for the composite containing 35 vol% of the glass. Polymer concrete samples did not show high impact resistance, which was in the range of 5.85 - 10.13 kJ/m2 . However, it increases with increasing glass content and the highest value was obtained for the composite containing 50% of the glass volume. Among the polymer concrete samples, the best properties were obtained for the mixture of 35% sand, 35% ground glass and 30% epoxy resin. Open porosity of traditional concrete is 15.9%, and for polymer concrete it was lower than 0.38%. The large difference in open porosity and water absorption for traditional concrete and polymer concrete, allow us to conclude that the latter will have higher frost resistance. The test results clearly show the significantly better mechanical properties of polymer concrete than of traditional concrete.
{"title":"The application of automotive glass waste in the production of epoxy polymer concrete","authors":"J. Smoleń, Berk Değirmenci, Berke Doğuş Tekeli, Bartłomiej Nowacki","doi":"10.32047/cwb.2021.26.5.4","DOIUrl":"https://doi.org/10.32047/cwb.2021.26.5.4","url":null,"abstract":"In this paper, the production of aggregate from car windshield cullet and the use of this aggregate, in various compositions with fine quartz sand, as the reinforcing phase of the epoxy matrix polymer concrete were used and the obtained samples were tested. The bending and compressive strength, Charpy’s impact resistance tests were performed on the obtained composites. The porosity, water absorption, and density were also determined. The tests performed have shown that the application of car windshield cullet in polymer concrete, seems to be a good way to recycle this waste. The highest compressive strength, equal to 101 MPa, was obtained by composites containing 20 vol% of milled glass. It is nearly 7 times higher than the value of traditional concrete tested simultaneously, which has about 15 MPa. The highest flexural strength was noted for the composite containing 35 vol% of the glass. Polymer concrete samples did not show high impact resistance, which was in the range of 5.85 - 10.13 kJ/m2 . However, it increases with increasing glass content and the highest value was obtained for the composite containing 50% of the glass volume. Among the polymer concrete samples, the best properties were obtained for the mixture of 35% sand, 35% ground glass and 30% epoxy resin. Open porosity of traditional concrete is 15.9%, and for polymer concrete it was lower than 0.38%. The large difference in open porosity and water absorption for traditional concrete and polymer concrete, allow us to conclude that the latter will have higher frost resistance. The test results clearly show the significantly better mechanical properties of polymer concrete than of traditional concrete.","PeriodicalId":55632,"journal":{"name":"Cement Wapno Beton","volume":"30 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85259783","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.32047/cwb.2021.26.6.7
S. Karakuş, I. Sanrı Karapınar, Onur Pehlivan, Ayşe Elif Özsoy Özbay, U. Yazgan
In this paper, a novel nanocomposite containing biodegradable chitosan [CS] and modified zeolite [mZeo] was introduced as a cement eco-nano additive and its effects on the mechanical properties of cement mortars were evaluated. The proposed nanocomposite was prepared by using a synergistic sonication-microwave method. The surface morphology and chemical compositions of mZeo and CS/ mZeo nanocomposites were determined using SEM, FTIR, XRF, and BET. Compressive and flexural strength of cement mortars containing mZeo and CS/mZeo in ratios of 0%, 0.2%, 0.5%, 1% and 2% by mass, were investigated. Experimental results showed a significant improvement in the mechanical properties of mortars containing the proposed nanocomposite. The use of nanoscale zeolite in cementitious composites was attempted for the first time within this study and the results so far have been very promising. Therefore, it is concluded that the proposed nanocomposite has great potential to be used as an alternative eco-nano additive, for cementitious composites.
{"title":"Synthesis of novel chitosan/modified zeolite nanocomposites and their effect on the mechanical properties of cement mortars","authors":"S. Karakuş, I. Sanrı Karapınar, Onur Pehlivan, Ayşe Elif Özsoy Özbay, U. Yazgan","doi":"10.32047/cwb.2021.26.6.7","DOIUrl":"https://doi.org/10.32047/cwb.2021.26.6.7","url":null,"abstract":"In this paper, a novel nanocomposite containing biodegradable chitosan [CS] and modified zeolite [mZeo] was introduced as a cement eco-nano additive and its effects on the mechanical properties of cement mortars were evaluated. The proposed nanocomposite was prepared by using a synergistic sonication-microwave method. The surface morphology and chemical compositions of mZeo and CS/ mZeo nanocomposites were determined using SEM, FTIR, XRF, and BET. Compressive and flexural strength of cement mortars containing mZeo and CS/mZeo in ratios of 0%, 0.2%, 0.5%, 1% and 2% by mass, were investigated. Experimental results showed a significant improvement in the mechanical properties of mortars containing the proposed nanocomposite. The use of nanoscale zeolite in cementitious composites was attempted for the first time within this study and the results so far have been very promising. Therefore, it is concluded that the proposed nanocomposite has great potential to be used as an alternative eco-nano additive, for cementitious composites.","PeriodicalId":55632,"journal":{"name":"Cement Wapno Beton","volume":"98 4 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79427196","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.32047/cwb.2021.26.2.9
Süleyman Karahan, H. Güneyli, Aslιhan Güneyli
The effect of flakiness, one of the shape property of aggregate on concrete, is not an issue sufficiently clarified. In addition, there are no satisfactorily detailed limitations for flakiness on a global scale. This study, in which limestone was used as an aggregate, describes the dependence of flakiness on the concrete behaviour both in the fresh and hardened state. In this context, slump tests in the fresh state and compressive strength tests in the hardened state at 7, 28 and 60 days were carried out using concrete mixes prepared in the same design and with different fl akiness percentages. An increase of flaky particle fraction in coarse aggregate caused flocculation and segregation leading to the inhomogeneity of concrete mix. The slump of the mix decreased markedly as the flakiness increased, and an increase in flakiness by 25% resulted in an average reduction of 18 mm in the slump value. The test results indicated that the compressive strength of concrete decreased significantly with increasing flakiness. According to these negative linear relationships with strong correlation coefficients, an increase in the flaky coarse particles by 25% led to a decrease in compressive strength of average 0.9, 0.4 and 1.2 MPa for the curing times of 7, 28 and 60 days, respectively. Furthermore, the increase in flakiness enhanced particularly the range and standard deviation of compressive strength values with the same flakiness percentage, which this trend was most pronounced and meaningful at 60 days. This phenomenon exhibits that the differences and uncertainty in the compressive strength of the concrete specimens with the same flakiness percentage, increase distinctly with the increase in the flakiness.
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