Marek Kawulok, S. Pospíšil, N. Freiherrová, D. Juračka
This paper aims to investigate the behavior of a spherical absorber composed of two parts, an inner sphere and a supporting convex spherical dish in which the ball is placed. Considering only the planar behavior of the system, a set of governing nonlinear differential equations was derived and solved numerically. Firstly, the system is exposed to the harmonic excitation of the supporting bowl and its time response is analyzed for all time dependent variables. By gradually changing the angular frequency of the excitation, a resonance curve is obtained, which is examined in detail with respect to the changing amplitudes of the excitation force and the nonlinear behavior. The effect of internal damping and different settings of the absorber characteristics are also investigated. The effect of initial conditions without the presence of an external excitation force is also numerically analyzed by means of phase portraits for selected pairs of initial conditions.
{"title":"Numerical Simulation of a Planar Model of a Ball Absorber in a Spherical Dish","authors":"Marek Kawulok, S. Pospíšil, N. Freiherrová, D. Juračka","doi":"10.3311/ppci.21725","DOIUrl":"https://doi.org/10.3311/ppci.21725","url":null,"abstract":"This paper aims to investigate the behavior of a spherical absorber composed of two parts, an inner sphere and a supporting convex spherical dish in which the ball is placed. Considering only the planar behavior of the system, a set of governing nonlinear differential equations was derived and solved numerically. Firstly, the system is exposed to the harmonic excitation of the supporting bowl and its time response is analyzed for all time dependent variables. By gradually changing the angular frequency of the excitation, a resonance curve is obtained, which is examined in detail with respect to the changing amplitudes of the excitation force and the nonlinear behavior. The effect of internal damping and different settings of the absorber characteristics are also investigated. The effect of initial conditions without the presence of an external excitation force is also numerically analyzed by means of phase portraits for selected pairs of initial conditions.","PeriodicalId":49705,"journal":{"name":"Periodica Polytechnica-Civil Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2023-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76302406","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}
A significant issue that researchers have been addressing recently is the recycling of various waste materials from different industries. Annually, millions of tons of waste are released. Pollution and safe, cost-effective disposal are critical issues with these waste materials. This study aims to investigate usability of concrete waste (COW) and ceramic waste (CEW) as filler material in Hot Mix Asphalt (HMA). Firstly, in this direction, a series of tests were conducted to determine the optimum bitumen content. Five different bitumen contents (i.e., 4.5%, 5%, 5.5%, 6%, and 6.5%) were used to prepare asphalt concrete samples. The Marshall Stability (MS) test was then performed on the prepared samples using various filler ratios, including limestone (LS), concrete waste (COW), and/or ceramic waste (CEW). Selecting the series of asphalt with 4% filler that has provided the maximum stability, COW or CEW was replaced with LS filler at rates of 25%, 50%, 75%, and 100%. Consequently, the use of COW or CEW as a mineral filler in HMA was found to be suitable.
{"title":"Utilization of Recyclable Concrete and Ceramic Waste as Filling Material in Hot Mix Asphalt","authors":"S. Serin, Y. Önal, C. Kayadelen, N. Morova","doi":"10.3311/ppci.21352","DOIUrl":"https://doi.org/10.3311/ppci.21352","url":null,"abstract":"A significant issue that researchers have been addressing recently is the recycling of various waste materials from different industries. Annually, millions of tons of waste are released. Pollution and safe, cost-effective disposal are critical issues with these waste materials. This study aims to investigate usability of concrete waste (COW) and ceramic waste (CEW) as filler material in Hot Mix Asphalt (HMA). Firstly, in this direction, a series of tests were conducted to determine the optimum bitumen content. Five different bitumen contents (i.e., 4.5%, 5%, 5.5%, 6%, and 6.5%) were used to prepare asphalt concrete samples. The Marshall Stability (MS) test was then performed on the prepared samples using various filler ratios, including limestone (LS), concrete waste (COW), and/or ceramic waste (CEW). Selecting the series of asphalt with 4% filler that has provided the maximum stability, COW or CEW was replaced with LS filler at rates of 25%, 50%, 75%, and 100%. Consequently, the use of COW or CEW as a mineral filler in HMA was found to be suitable.","PeriodicalId":49705,"journal":{"name":"Periodica Polytechnica-Civil Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2023-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75242665","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}
Occurred damages on the bridge piers during earthquakes lead to significant financial losses worldwide every year and can cause social problems by disrupting traffic flow and transportation services. Rocking isolation of foundations is one of the damage reduction approaches to avoid structural damage on piers by transferring plastic hinges from piers to underlying soil media. The behavior of rocking foundations on non-plastic silts has not been investigated well until now in the literature. In this research, the characteristic seismic behavior of a bridge pier considering rocking isolation is evaluated using small-scale physical modeling tests. To this aim, eight shaking table tests (with sinusoidal excitations) are conducted where both sandy and silty materials are employed as the soil media. In addition to the effects of the underlying soil, the effects of the critical contact area ratio of the foundation and frequency of input motions are evaluated. Achieved results indicate that the considered bridge pier shows the same behavior trend for underlying silty soil and sandy one. However, because of the frequency-dependent behavior of non-plastic silty soil, the pier attracts lower accelerations and higher moments. Therefore, the achieved results show that the proposed design approaches of rocking foundations that are mostly extracted based on experimental studies on sands (or rarely on clay) can lead to non-conservative designs in silty soils.
{"title":"Investigation on the Behavior of Bridge Piers Considering Rocking Isolation Constructed on Non-plastic Silts and Sands Using 1g Shaking Table Tests","authors":"Arash Esmatkhah Irani, Masoud Hajialilue Bonab, Fariba Behrooz Sarand, H. Katebi","doi":"10.3311/ppci.21713","DOIUrl":"https://doi.org/10.3311/ppci.21713","url":null,"abstract":"Occurred damages on the bridge piers during earthquakes lead to significant financial losses worldwide every year and can cause social problems by disrupting traffic flow and transportation services. Rocking isolation of foundations is one of the damage reduction approaches to avoid structural damage on piers by transferring plastic hinges from piers to underlying soil media. The behavior of rocking foundations on non-plastic silts has not been investigated well until now in the literature. In this research, the characteristic seismic behavior of a bridge pier considering rocking isolation is evaluated using small-scale physical modeling tests. To this aim, eight shaking table tests (with sinusoidal excitations) are conducted where both sandy and silty materials are employed as the soil media. In addition to the effects of the underlying soil, the effects of the critical contact area ratio of the foundation and frequency of input motions are evaluated. Achieved results indicate that the considered bridge pier shows the same behavior trend for underlying silty soil and sandy one. However, because of the frequency-dependent behavior of non-plastic silty soil, the pier attracts lower accelerations and higher moments. Therefore, the achieved results show that the proposed design approaches of rocking foundations that are mostly extracted based on experimental studies on sands (or rarely on clay) can lead to non-conservative designs in silty soils.","PeriodicalId":49705,"journal":{"name":"Periodica Polytechnica-Civil Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2023-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87982306","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}
In view of the problem that high concentration of dust is easily generated during rock tunnel drilling and blasting construction, explosive water mist to reduce dust is given in this paper. Water bag is set up on tunnel face and explosive water mist is used to reduce blasting dust concentration. With the help of numerical simulation software FLUENT and combined with theoretical analysis, The key parameters of explosion fog and dust reduction technology are obtained: water bag spacing, blasting time difference, water bag layout position, etc., which provides a theoretical basis for practical application of the technology. At the same time, combined with the field test of Huangtai tunnel blasting, the dust concentration with and without water mist was measured, respectively. The results show that the maximum dust removal rate of the tunnel section under the dust removal measures with water mist can reach 80.85%, the average dust removal rate can reach 65.16%. So, the dust removal effect is remarkable.
{"title":"Study on Dust Removal Technology of Explosive Water Mist in Drill and Blast Tunnelling","authors":"Jianjun Shi, H. Zhao, Wen-ke Xu, W. Zhang, H. An","doi":"10.3311/ppci.21678","DOIUrl":"https://doi.org/10.3311/ppci.21678","url":null,"abstract":"In view of the problem that high concentration of dust is easily generated during rock tunnel drilling and blasting construction, explosive water mist to reduce dust is given in this paper. Water bag is set up on tunnel face and explosive water mist is used to reduce blasting dust concentration. With the help of numerical simulation software FLUENT and combined with theoretical analysis, The key parameters of explosion fog and dust reduction technology are obtained: water bag spacing, blasting time difference, water bag layout position, etc., which provides a theoretical basis for practical application of the technology. At the same time, combined with the field test of Huangtai tunnel blasting, the dust concentration with and without water mist was measured, respectively. The results show that the maximum dust removal rate of the tunnel section under the dust removal measures with water mist can reach 80.85%, the average dust removal rate can reach 65.16%. So, the dust removal effect is remarkable.","PeriodicalId":49705,"journal":{"name":"Periodica Polytechnica-Civil Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2023-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85791212","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}
This paper proposes a novel algorithm to optimize the discrete time-cost trade-off problem (DTCTP) in construction projects. As DTCTP is assumed NP-hard, the new metaheuristic models are investigated to contribute for decision-making of project managers. DTCTP can be modelled as multi-mode to represent real-life problems more practical. According to the model, the project activities have at least two or more durations and cost alternative modes. For solving this problem effectively, a novel optimization metaheuristic method named Advanced Jaya Algorithm (A-JA) is proposed, which is generated from Jaya Algorithm (JA). The benchmark function tests are applied to verify the model with other well-known metaheuristic methods. The key weakness of the base algorithm JA is that, it has unstable solution accuracy and low likelihood of escaping local optimums. According to the results, A-JA considerably improves these areas. Two case studies of DTCTP are carried out after verification to demonstrate the effectiveness and efficiency of the proposed algorithm in comparison with JA and three well-known methods. The results of A-JA are found to be more powerful than the base algorithm JA and the benchmark algorithms. The proposed method achieves the Pareto fronts to help decision makers to make trade-off between the objectives and choose the optimum solution considering on their preference.
{"title":"Optimizing of Discrete Time-cost Trade-off Problem in Construction Projects Using Advanced Jaya Algorithm","authors":"Gülçağ Albayrak","doi":"10.3311/ppci.22156","DOIUrl":"https://doi.org/10.3311/ppci.22156","url":null,"abstract":"This paper proposes a novel algorithm to optimize the discrete time-cost trade-off problem (DTCTP) in construction projects. As DTCTP is assumed NP-hard, the new metaheuristic models are investigated to contribute for decision-making of project managers. DTCTP can be modelled as multi-mode to represent real-life problems more practical. According to the model, the project activities have at least two or more durations and cost alternative modes. For solving this problem effectively, a novel optimization metaheuristic method named Advanced Jaya Algorithm (A-JA) is proposed, which is generated from Jaya Algorithm (JA). The benchmark function tests are applied to verify the model with other well-known metaheuristic methods. The key weakness of the base algorithm JA is that, it has unstable solution accuracy and low likelihood of escaping local optimums. According to the results, A-JA considerably improves these areas. Two case studies of DTCTP are carried out after verification to demonstrate the effectiveness and efficiency of the proposed algorithm in comparison with JA and three well-known methods. The results of A-JA are found to be more powerful than the base algorithm JA and the benchmark algorithms. The proposed method achieves the Pareto fronts to help decision makers to make trade-off between the objectives and choose the optimum solution considering on their preference.","PeriodicalId":49705,"journal":{"name":"Periodica Polytechnica-Civil Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2023-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80150246","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}
Environmental protection approach has caused to ignore the conditions and the possibility of using solid waste as a substitute for concrete. In this research, the effect of glass powder in percentages of 0-30 (in steps of 7.5%) and micro-silica (10% as a constant) as a substitute for cement is investigated on efficiency, compressive strength, tensile strength, and bending strength. surface water absorption, capillary water absorption, and freeze/thaw cycle are paid. The results showed that the use of glass powder leads to increases the fluidity and properties of fresh concrete. The mechanical parameters decrease slightly when 30% of cement is replaced with glass powder.
{"title":"Mechanical and Durability Properties of Sustainable Self-compacting Concrete with Waste Glass Powder and Silica Fume","authors":"Mahdi Jalalinejad, A. Hemmati, A. Mortezaei","doi":"10.3311/ppci.21537","DOIUrl":"https://doi.org/10.3311/ppci.21537","url":null,"abstract":"Environmental protection approach has caused to ignore the conditions and the possibility of using solid waste as a substitute for concrete. In this research, the effect of glass powder in percentages of 0-30 (in steps of 7.5%) and micro-silica (10% as a constant) as a substitute for cement is investigated on efficiency, compressive strength, tensile strength, and bending strength. surface water absorption, capillary water absorption, and freeze/thaw cycle are paid. The results showed that the use of glass powder leads to increases the fluidity and properties of fresh concrete. The mechanical parameters decrease slightly when 30% of cement is replaced with glass powder.","PeriodicalId":49705,"journal":{"name":"Periodica Polytechnica-Civil Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2023-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83871145","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}
Stabilizing piles are extensively used as an effective landslide control treatment, and the soil arching effect is the key element for the performance of the pile system. Most previous studies on soil arching effect and its application in stabilizing piles were conducted with laboratory tests and numerical simulations, while limited efforts have been dedicated to the analytical characterization of such a soil-structure interaction. In this paper, a new stress-reduction model for soil arch in landslides is established by theoretical derivation. Our model calculation has demonstrated an exponential reduction in the stress along the direction of slipping between and behind stabilizing piles and thus justifies the observations of laboratory tests and numerical simulations. Thereafter, the analytical solutions to the two key arch shape parameters, namely the inclination angle at the foothold and the thickness of soil arch, are derived based on the proposed stress-reduction model. Then, the ultimate bearing capacity of soil arch between and behind stabilizing piles is subsequently calculated, and a three-level load sharing model for landslides is thus proposed based on the stress-reduction mode. The load sharing model can well capture the stage characteristics of the interaction between landslide mass and stabilizing piles. Finally, the calculation model of spacing between stabilizing piles is established based on the proposed stress-reduction model, and it turns to be good in field application. The findings of this study can contribute to a better understanding of the soil arching effect as well as a better design of the stabilizing piles.
{"title":"A New Stress-reduction Model for Soil Arch in Landslides","authors":"Xing-ming Li, E. Yan, Miao Sun, Xiangqian Yao, Shuo Li, Cheng Gao, Qian Chen","doi":"10.3311/ppci.22054","DOIUrl":"https://doi.org/10.3311/ppci.22054","url":null,"abstract":"Stabilizing piles are extensively used as an effective landslide control treatment, and the soil arching effect is the key element for the performance of the pile system. Most previous studies on soil arching effect and its application in stabilizing piles were conducted with laboratory tests and numerical simulations, while limited efforts have been dedicated to the analytical characterization of such a soil-structure interaction. In this paper, a new stress-reduction model for soil arch in landslides is established by theoretical derivation. Our model calculation has demonstrated an exponential reduction in the stress along the direction of slipping between and behind stabilizing piles and thus justifies the observations of laboratory tests and numerical simulations. Thereafter, the analytical solutions to the two key arch shape parameters, namely the inclination angle at the foothold and the thickness of soil arch, are derived based on the proposed stress-reduction model. Then, the ultimate bearing capacity of soil arch between and behind stabilizing piles is subsequently calculated, and a three-level load sharing model for landslides is thus proposed based on the stress-reduction mode. The load sharing model can well capture the stage characteristics of the interaction between landslide mass and stabilizing piles. Finally, the calculation model of spacing between stabilizing piles is established based on the proposed stress-reduction model, and it turns to be good in field application. The findings of this study can contribute to a better understanding of the soil arching effect as well as a better design of the stabilizing piles.","PeriodicalId":49705,"journal":{"name":"Periodica Polytechnica-Civil Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2023-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74943885","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}
Optimizing a structure's topology involves finding the best possible distribution of material and connections within a given design space. It has a significant effect on its performance, which is why there has been a meteoric rise in the number of articles published on the topic over the last two decades. This work offers an investigation of reliability-based topology optimization of structures, in light of the recent development of several topology optimization techniques for both linear and nonlinear systems. Therefore, the emphasis of this study is on the latest advancements, enhancements, and applications of reliability-based topology optimization. This paper's primary objective is to provide an overview of the latest advancements in the reliability-based topology optimization of structures, with a particular emphasis on the recent improvement of integrating reliability-based design into the bi-directional evolutionary structural optimization (BESO) method, which accounts for the topological optimization of geometric and material nonlinearity as well as thermoelastic problems.
{"title":"An Investigation of the Recent Developments in Reliability-based Structural Topology Optimization","authors":"M. Habashneh, M. Movahedi Rad","doi":"10.3311/ppci.22107","DOIUrl":"https://doi.org/10.3311/ppci.22107","url":null,"abstract":"Optimizing a structure's topology involves finding the best possible distribution of material and connections within a given design space. It has a significant effect on its performance, which is why there has been a meteoric rise in the number of articles published on the topic over the last two decades. This work offers an investigation of reliability-based topology optimization of structures, in light of the recent development of several topology optimization techniques for both linear and nonlinear systems. Therefore, the emphasis of this study is on the latest advancements, enhancements, and applications of reliability-based topology optimization. This paper's primary objective is to provide an overview of the latest advancements in the reliability-based topology optimization of structures, with a particular emphasis on the recent improvement of integrating reliability-based design into the bi-directional evolutionary structural optimization (BESO) method, which accounts for the topological optimization of geometric and material nonlinearity as well as thermoelastic problems.","PeriodicalId":49705,"journal":{"name":"Periodica Polytechnica-Civil Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2023-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82867363","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}
Jianfei Yang, Guodong Zhang, Lixu Deng, Yaxin Zhang, Zheng Li, Y. Ye
The rock mass in the hydro-fluctuating zone of the reservoir bank slope is under dry-wet cycles for a long time, which will cause the deterioration of rock mass and induce geological disasters. In this study, a series of dry-wet cycle tests on the argillaceous quartz sandstone in the Three Gorges Reservoir area was carried out. Then, after different dry-wet cycles, the sandstone specimens were used to conduct the Brazilian splitting, scanning electron microscope, and 3D laser scanning tests. Herein, we provided detailed physical and microscopy image data to analyze the deterioration effect of tensile strength and mesostructure deterioration process of sandstone. With the increase of dry-wet cycles, the tensile strength of sandstone initially decreases rapidly, and then the decline rate tends to slow down. The evolution laws of fractal dimension and porosity are also significantly consistent with the deterioration of tensile strength. Moreover, further mesostructural analysis has revealed the repeated “absorption and swelling-dehydration and contraction” of clay minerals. This results in the breakage of framework mineral quartz and the expansion and connectivity of internal cracks, which ultimately deteriorates sandstone’s tensile strength.
{"title":"Deterioration Effect of Sandstone Tensile Strength and Its Mesoscopic Mechanism under Dry-wet Cycles","authors":"Jianfei Yang, Guodong Zhang, Lixu Deng, Yaxin Zhang, Zheng Li, Y. Ye","doi":"10.3311/ppci.22007","DOIUrl":"https://doi.org/10.3311/ppci.22007","url":null,"abstract":"The rock mass in the hydro-fluctuating zone of the reservoir bank slope is under dry-wet cycles for a long time, which will cause the deterioration of rock mass and induce geological disasters. In this study, a series of dry-wet cycle tests on the argillaceous quartz sandstone in the Three Gorges Reservoir area was carried out. Then, after different dry-wet cycles, the sandstone specimens were used to conduct the Brazilian splitting, scanning electron microscope, and 3D laser scanning tests. Herein, we provided detailed physical and microscopy image data to analyze the deterioration effect of tensile strength and mesostructure deterioration process of sandstone. With the increase of dry-wet cycles, the tensile strength of sandstone initially decreases rapidly, and then the decline rate tends to slow down. The evolution laws of fractal dimension and porosity are also significantly consistent with the deterioration of tensile strength. Moreover, further mesostructural analysis has revealed the repeated “absorption and swelling-dehydration and contraction” of clay minerals. This results in the breakage of framework mineral quartz and the expansion and connectivity of internal cracks, which ultimately deteriorates sandstone’s tensile strength.","PeriodicalId":49705,"journal":{"name":"Periodica Polytechnica-Civil Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2023-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73503384","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}
In this study, the influence of the activator type on the physical and mechanical properties of the geopolymer mortars was analyzed. C and F-class fly ash (FA), blast furnace slag (BFS), sodium hydroxide (NH), sodium metasilicate (NS), standard sand, and distilled water were used in the production of mortar specimens. All specimens were cured at room temperature. C and F-class fly ash usage ratios are 0%, 15%, and 30%. NH was used as an activator in the 1st group of the produced geopolymer mortars, and NS with NH was used in the 2nd group. 5 series were produced and a flow-table test, ultrasonic pulse velocity test, flexural strength test, compressive strength test, and Scanning Electron Microscope-Energy Dispersive Spectrometry (SEM-EDS) microstructure analysis were applied to the samples. The addition of NS increased the compressive strength and the greatest increase occurred in the reference sample by 113%. It also increased the compressive strength of FAF30 by 60% in comparison to FAC30. Following the results of the SEM examination, when the reference samples were compared, the addition of NS inhibited the formation of cracks. According to the SEM-EDS analysis results, an increase in the F and C-class FA ratio improved the crack formation. Compared to F-class FA, FAC30 has more cracks due to the lower SiO2 content in C-class FA. High K content and SiO2 ratio, as determined by EDS analysis, boost the alkalinity and positively impact the strength.
{"title":"Effect of Activator Type on Geopolymer Mortars Containing Different Types of Fly Ash","authors":"","doi":"10.3311/ppci.21945","DOIUrl":"https://doi.org/10.3311/ppci.21945","url":null,"abstract":"In this study, the influence of the activator type on the physical and mechanical properties of the geopolymer mortars was analyzed. C and F-class fly ash (FA), blast furnace slag (BFS), sodium hydroxide (NH), sodium metasilicate (NS), standard sand, and distilled water were used in the production of mortar specimens. All specimens were cured at room temperature. C and F-class fly ash usage ratios are 0%, 15%, and 30%. NH was used as an activator in the 1st group of the produced geopolymer mortars, and NS with NH was used in the 2nd group. 5 series were produced and a flow-table test, ultrasonic pulse velocity test, flexural strength test, compressive strength test, and Scanning Electron Microscope-Energy Dispersive Spectrometry (SEM-EDS) microstructure analysis were applied to the samples. The addition of NS increased the compressive strength and the greatest increase occurred in the reference sample by 113%. It also increased the compressive strength of FAF30 by 60% in comparison to FAC30. Following the results of the SEM examination, when the reference samples were compared, the addition of NS inhibited the formation of cracks. According to the SEM-EDS analysis results, an increase in the F and C-class FA ratio improved the crack formation. Compared to F-class FA, FAC30 has more cracks due to the lower SiO2 content in C-class FA. High K content and SiO2 ratio, as determined by EDS analysis, boost the alkalinity and positively impact the strength.","PeriodicalId":49705,"journal":{"name":"Periodica Polytechnica-Civil Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2023-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75126548","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}
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