Abstract This study evaluated the mechanical properties of the scrimber wood produced from date palm fronds and compared it to other wood-based materials. The raw materials for the production of the scrimber wood were date palm fronds. The scrimber wood was produced using a fabrication process that included the following stages: washing, cutting, burning, and gluing the pieces. The results showed that the mechanical properties of the scrimber wood produced using date palm fronds were very similar to those of other woods used for the same purpose. It was found that the wood produced was strong enough to hold several heavy objects without deforming or breaking. In addition, no defects, such as cracks or holes, were observed on the surface of the wood after processing. The results revealed that frond-scrimber trees recorded the largest deflection before fracture due to their fibrous features. The fibrous structure of the frond scrim may explain its strength and durability, as it successfully supplied samples with high fracture points, similar to hardwood, and prolonged maximum displacement, similar to certain softwoods. The dynamic characterization of the scrimber wood specimens reveals their inherent frequencies, mode forms, damping ratios, and other dynamic properties; such insights may help forecast their performance under different loads.
{"title":"Evaluation of the mechanical and dynamic properties of scrimber wood produced from date palm fronds","authors":"Ghassan Mousa, Muhammad Basha, Essam B. Moustafa","doi":"10.1515/jmbm-2022-0305","DOIUrl":"https://doi.org/10.1515/jmbm-2022-0305","url":null,"abstract":"Abstract This study evaluated the mechanical properties of the scrimber wood produced from date palm fronds and compared it to other wood-based materials. The raw materials for the production of the scrimber wood were date palm fronds. The scrimber wood was produced using a fabrication process that included the following stages: washing, cutting, burning, and gluing the pieces. The results showed that the mechanical properties of the scrimber wood produced using date palm fronds were very similar to those of other woods used for the same purpose. It was found that the wood produced was strong enough to hold several heavy objects without deforming or breaking. In addition, no defects, such as cracks or holes, were observed on the surface of the wood after processing. The results revealed that frond-scrimber trees recorded the largest deflection before fracture due to their fibrous features. The fibrous structure of the frond scrim may explain its strength and durability, as it successfully supplied samples with high fracture points, similar to hardwood, and prolonged maximum displacement, similar to certain softwoods. The dynamic characterization of the scrimber wood specimens reveals their inherent frequencies, mode forms, damping ratios, and other dynamic properties; such insights may help forecast their performance under different loads.","PeriodicalId":17354,"journal":{"name":"Journal of the Mechanical Behavior of Materials","volume":"52 41","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139126777","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract The study focused on examining the behavior of six concrete beams that were reinforced with glass fiber-reinforced polymer (GFRP) bars to evaluate their performance in terms of their load-carrying capacity, deflection, and other mechanical properties. The experimental investigation would provide insights into the feasibility and effectiveness of GFRP bars as an alternative to traditional reinforcement materials like steel bars in concrete structures. The GFRP bars were used in both the longitudinal and transverse directions. Each beam in the study shared the following specifications: an overall length of 2,400 mm, a clear span of 2,100 mm, and a rectangular cross-section measuring 300 mm in width and 250 mm in depth. To apply loads for testing, two-point static loads were placed at the middle third of the beam’s span, creating a shear span of 700 mm in length. The beams were categorized into three groups depending on the GFRP longitudinal reinforcement ratio in the tension and compression zones of the section. GFRP bars with a diameter of 15 mm were employed as longitudinal reinforcement, while closed GFRP stirrups with a diameter of 8 mm at 100 mm were utilized as transverse reinforcement throughout the structural element. Test results have indicated that the ultimate load capacity of doubly GFRP-reinforced concrete beams varies compared to singly GFRP-reinforced beams. The range of variation observed is between an increase of 8% and a decrease of 4%. Accordingly, the contribution of the GFRP bars in the compression zone is insignificant and could be ignored in design calculations. It was observed that the loading level at which crack spacing stabilized ranged between 31.3 and 87% of the experimental failure load. It seems that the crack spacing decreased with the increase in the reinforcement ratio.
{"title":"Performance of doubly reinforced concrete beams with GFRP bars","authors":"Musa AbdulMuttalib Issa, A. Allawi, Nazar Oukaili","doi":"10.1515/jmbm-2022-0308","DOIUrl":"https://doi.org/10.1515/jmbm-2022-0308","url":null,"abstract":"Abstract The study focused on examining the behavior of six concrete beams that were reinforced with glass fiber-reinforced polymer (GFRP) bars to evaluate their performance in terms of their load-carrying capacity, deflection, and other mechanical properties. The experimental investigation would provide insights into the feasibility and effectiveness of GFRP bars as an alternative to traditional reinforcement materials like steel bars in concrete structures. The GFRP bars were used in both the longitudinal and transverse directions. Each beam in the study shared the following specifications: an overall length of 2,400 mm, a clear span of 2,100 mm, and a rectangular cross-section measuring 300 mm in width and 250 mm in depth. To apply loads for testing, two-point static loads were placed at the middle third of the beam’s span, creating a shear span of 700 mm in length. The beams were categorized into three groups depending on the GFRP longitudinal reinforcement ratio in the tension and compression zones of the section. GFRP bars with a diameter of 15 mm were employed as longitudinal reinforcement, while closed GFRP stirrups with a diameter of 8 mm at 100 mm were utilized as transverse reinforcement throughout the structural element. Test results have indicated that the ultimate load capacity of doubly GFRP-reinforced concrete beams varies compared to singly GFRP-reinforced beams. The range of variation observed is between an increase of 8% and a decrease of 4%. Accordingly, the contribution of the GFRP bars in the compression zone is insignificant and could be ignored in design calculations. It was observed that the loading level at which crack spacing stabilized ranged between 31.3 and 87% of the experimental failure load. It seems that the crack spacing decreased with the increase in the reinforcement ratio.","PeriodicalId":17354,"journal":{"name":"Journal of the Mechanical Behavior of Materials","volume":"15 7","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139394654","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Faten N. Al Zubaidi, Lamyaa Mahdi Asaad, Iqbal Alshalal, Mohammed Rasheed
Abstract In numerous engineering applications, metal matrix composites strengthened by ceramic particles have played an important role. For this purpose, an aluminum (Al 7075) nanocomposite has been fabricated, and nano-zirconium oxide of particle size 40 nm (0, 0.8, 1.6, and 2.4) wt% reinforced Al 7075 alloy was produced using a stir-casting process. The effect of ZrO 2 NPs loading on mechanical properties along with the detailed characterization were demonstrated. The performance of Al with ZrO 2 nanocomposite was investigated by Vickers hardness tester, scanning electron microscopy, energy-dispersive X-ray, compression test, Lee’s disc, and Shore D instruments were utilized to determine the hardness, structural morphology, composition of the elements, Young’s modulus, thermal conductivity, and roughness values of the samples, respectively. The hardness (120.3–177) HV, compression strength (624.2–878.6) MPa, yield modulus (38–70) MPa, surface roughness (0.876–0.606) µm, thermal conductivity (2.0–2.39) W/m 2 °C improved by increasing the wt% of ZrO 2 NP reinforcement particles. The implication of these findings shows that 5 wt% nano-ZrO 2 -reinforced Al 7075 composites yielded better performance than pure Al 7075 alloy. To sum up, this investigation demonstrated that the ZrO 2 reinforcement enhanced the mechanical properties of Al 7075.
{"title":"The impact of zirconia nanoparticles on the mechanical characteristics of 7075 aluminum alloy","authors":"Faten N. Al Zubaidi, Lamyaa Mahdi Asaad, Iqbal Alshalal, Mohammed Rasheed","doi":"10.1515/jmbm-2022-0302","DOIUrl":"https://doi.org/10.1515/jmbm-2022-0302","url":null,"abstract":"Abstract In numerous engineering applications, metal matrix composites strengthened by ceramic particles have played an important role. For this purpose, an aluminum (Al 7075) nanocomposite has been fabricated, and nano-zirconium oxide of particle size 40 nm (0, 0.8, 1.6, and 2.4) wt% reinforced Al 7075 alloy was produced using a stir-casting process. The effect of ZrO 2 NPs loading on mechanical properties along with the detailed characterization were demonstrated. The performance of Al with ZrO 2 nanocomposite was investigated by Vickers hardness tester, scanning electron microscopy, energy-dispersive X-ray, compression test, Lee’s disc, and Shore D instruments were utilized to determine the hardness, structural morphology, composition of the elements, Young’s modulus, thermal conductivity, and roughness values of the samples, respectively. The hardness (120.3–177) HV, compression strength (624.2–878.6) MPa, yield modulus (38–70) MPa, surface roughness (0.876–0.606) µm, thermal conductivity (2.0–2.39) W/m 2 °C improved by increasing the wt% of ZrO 2 NP reinforcement particles. The implication of these findings shows that 5 wt% nano-ZrO 2 -reinforced Al 7075 composites yielded better performance than pure Al 7075 alloy. To sum up, this investigation demonstrated that the ZrO 2 reinforcement enhanced the mechanical properties of Al 7075.","PeriodicalId":17354,"journal":{"name":"Journal of the Mechanical Behavior of Materials","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135102367","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract An earthquake is a random phenomenon in its intensity and frequency content. Since the earthquake is a signal that contains a band of frequencies, each frequency has a different energy. This means that the response of buildings to earthquakes depends not only on the intensity of the earthquake but on its frequency content as well. In this study, two different approaches have been used: deterministic approach which is the time history analysis to show how the intensity of earthquakes affects the building response, and the nondeterministic random vibration approach, which is to clarify the response in the frequency domain and to show the effect of dominant frequencies of the earthquake. Both a prototype and a 1:6 scaled model was used to simulate a two-story steel building. In the experiential part, a shaking table was used to simulate a 1:6 scaled El-Centro 1940 NS earthquake as a base excitation with different intensities (0.05, 0.15, and 0.32g). In the theoretical part, Abaqus software was adopted to simulate the numerical model of the building. The results showed that the deterministic approach may be a non-conservative approach.
{"title":"Dynamic response of a two-story steel structure subjected to earthquake excitation by using deterministic and nondeterministic approaches","authors":"Mustafa Qasim Dows, H. Al-Baghdadi","doi":"10.1515/jmbm-2022-0261","DOIUrl":"https://doi.org/10.1515/jmbm-2022-0261","url":null,"abstract":"Abstract An earthquake is a random phenomenon in its intensity and frequency content. Since the earthquake is a signal that contains a band of frequencies, each frequency has a different energy. This means that the response of buildings to earthquakes depends not only on the intensity of the earthquake but on its frequency content as well. In this study, two different approaches have been used: deterministic approach which is the time history analysis to show how the intensity of earthquakes affects the building response, and the nondeterministic random vibration approach, which is to clarify the response in the frequency domain and to show the effect of dominant frequencies of the earthquake. Both a prototype and a 1:6 scaled model was used to simulate a two-story steel building. In the experiential part, a shaking table was used to simulate a 1:6 scaled El-Centro 1940 NS earthquake as a base excitation with different intensities (0.05, 0.15, and 0.32g). In the theoretical part, Abaqus software was adopted to simulate the numerical model of the building. The results showed that the deterministic approach may be a non-conservative approach.","PeriodicalId":17354,"journal":{"name":"Journal of the Mechanical Behavior of Materials","volume":" ","pages":""},"PeriodicalIF":1.8,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44070732","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. I. Fadhil, Ahmed Ibrahim Fadhil Al-Adly, M. Fattah
Abstract A number of destructive and non-destructive tests were conducted on rock samples collected from various zones in northern Iraq. So far, for Iraqi rocks, few studies have correlated Schmidt hammer rebound (R) with both unconfined compressive strength (UCS) and Brazilian tensile strength (BTS). In this study, the objective is to develop a relationship between the rebound number of Schmidt hammer surface hardness (rebound number) and both the BTS and the unconfined compressive strength (UCS) of different types of northern Iraqi rocks. The required relationship should be based on measured values of the UCS, BT, and Schmidt hammer hardness. To determine the relationship between R and both the UCS and BTS, 120 intact rock samples were prepared and tested using a uniaxial compressive test machine, a Brazilian test apparatus, and an L-type Schmidt hammer test (BTS). Three different types of rock samples (sandstone, claystone, and limestone) were collected from several locations in northern Iraq (Domeez, Baadra, and Zawita). For the three types of rocks, a new linear correlation with a high value of the regression coefficient R 2 is presented, linking the UCS and BTS separately versus R. For the three types of rocks studied, the correlation between UCS and R is better than the correlation between Brazilian tensile strength (BTS) and R.
{"title":"Estimation of uniaxial compressive and indirect tensile strengths of intact rock from Schmidt hammer rebound number","authors":"A. I. Fadhil, Ahmed Ibrahim Fadhil Al-Adly, M. Fattah","doi":"10.1515/jmbm-2022-0255","DOIUrl":"https://doi.org/10.1515/jmbm-2022-0255","url":null,"abstract":"Abstract A number of destructive and non-destructive tests were conducted on rock samples collected from various zones in northern Iraq. So far, for Iraqi rocks, few studies have correlated Schmidt hammer rebound (R) with both unconfined compressive strength (UCS) and Brazilian tensile strength (BTS). In this study, the objective is to develop a relationship between the rebound number of Schmidt hammer surface hardness (rebound number) and both the BTS and the unconfined compressive strength (UCS) of different types of northern Iraqi rocks. The required relationship should be based on measured values of the UCS, BT, and Schmidt hammer hardness. To determine the relationship between R and both the UCS and BTS, 120 intact rock samples were prepared and tested using a uniaxial compressive test machine, a Brazilian test apparatus, and an L-type Schmidt hammer test (BTS). Three different types of rock samples (sandstone, claystone, and limestone) were collected from several locations in northern Iraq (Domeez, Baadra, and Zawita). For the three types of rocks, a new linear correlation with a high value of the regression coefficient R 2 is presented, linking the UCS and BTS separately versus R. For the three types of rocks studied, the correlation between UCS and R is better than the correlation between Brazilian tensile strength (BTS) and R.","PeriodicalId":17354,"journal":{"name":"Journal of the Mechanical Behavior of Materials","volume":" ","pages":""},"PeriodicalIF":1.8,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48593070","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Various process nonhomogeneities in the cold rolling lead to an uneven distribution of deformation across the strip cross-section, resulting in the induction of residual stresses. This study investigates the longitudinal residual stresses in cold-rolled EN AW-5083 aluminum alloy strips using the finite element method (FEM) to achieve reliable predictions. The impacts of process parameters, including the reduction ratio, coefficient of contact friction, and front and back tensions, were analyzed. Changes in residual stresses, depending on the process parameters, were determined by the distribution of linear and shear strains, as well as the strain hardening conditions at the exit part of the deformation zone. An increase in the reduction ratio from 20 to 50%, as well as an increase in the friction coefficient from 0.1 to 0.2, resulted in decreased stress values. The residual stresses on the strip surface, determined by the experimental deflection method, were consistent with the results obtained by FEM simulation. Under the impact of back and/or front tensions, there is a reduction in longitudinal residual stresses, with the front tension exerting the greatest influence. The research results show that the FEM is a reliable tool for predicting residual stresses in cold-rolled strips.
{"title":"An analysis of longitudinal residual stresses in EN AW-5083 alloy strips as a function of cold-rolling process parameters","authors":"N. Tadić, M. Mišović, Ž. Radović","doi":"10.1515/jmbm-2022-0297","DOIUrl":"https://doi.org/10.1515/jmbm-2022-0297","url":null,"abstract":"Abstract Various process nonhomogeneities in the cold rolling lead to an uneven distribution of deformation across the strip cross-section, resulting in the induction of residual stresses. This study investigates the longitudinal residual stresses in cold-rolled EN AW-5083 aluminum alloy strips using the finite element method (FEM) to achieve reliable predictions. The impacts of process parameters, including the reduction ratio, coefficient of contact friction, and front and back tensions, were analyzed. Changes in residual stresses, depending on the process parameters, were determined by the distribution of linear and shear strains, as well as the strain hardening conditions at the exit part of the deformation zone. An increase in the reduction ratio from 20 to 50%, as well as an increase in the friction coefficient from 0.1 to 0.2, resulted in decreased stress values. The residual stresses on the strip surface, determined by the experimental deflection method, were consistent with the results obtained by FEM simulation. Under the impact of back and/or front tensions, there is a reduction in longitudinal residual stresses, with the front tension exerting the greatest influence. The research results show that the FEM is a reliable tool for predicting residual stresses in cold-rolled strips.","PeriodicalId":17354,"journal":{"name":"Journal of the Mechanical Behavior of Materials","volume":" ","pages":""},"PeriodicalIF":1.8,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45936490","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Increasing salinity in the Shatt Al-Arab River (SAR), south of Iraq, causes a serious issue with its water quality. In the current work, the proposed inflatable rubber dam was tested and verified for its feasibility and suitability on the SAR, Southern Iraq. The proposed rubber dam investigated its performance in reducing the salt front resulting from the seawater of the Arabian/Persian Gulf. Also, the inflatable rubber dam was feasibly compared with other types of hydraulic structure regulators and discussed the probable effect and benefits for each. Results of performance evaluation on the water quality were expressed in three groups: hydraulic, geotechnical, and economic performance. Results of the analyses of hydraulic indicators showed that the tide phenomenon has a significant impact on the water quality of the SAR. The geotechnical performance was assessed in terms of soil layers and was satisfactory. Analysis of the economic performance indicators showed that the inflatable rubber dam was feasible for the SAR problem compared with other types. Finally, a proposed design indicates the viability of inflatable rubber dam technology in controlling the salt front and improving the quality of the Shatt Al-Arab River water by reducing the salinity.
{"title":"Proposing an inflatable rubber dam on the Tidal Shatt Al-Arab River, Southern Iraq","authors":"Hazim Alkhafaji, W. Muttashar, W. M. Al-Mosawi","doi":"10.1515/jmbm-2022-0201","DOIUrl":"https://doi.org/10.1515/jmbm-2022-0201","url":null,"abstract":"Abstract Increasing salinity in the Shatt Al-Arab River (SAR), south of Iraq, causes a serious issue with its water quality. In the current work, the proposed inflatable rubber dam was tested and verified for its feasibility and suitability on the SAR, Southern Iraq. The proposed rubber dam investigated its performance in reducing the salt front resulting from the seawater of the Arabian/Persian Gulf. Also, the inflatable rubber dam was feasibly compared with other types of hydraulic structure regulators and discussed the probable effect and benefits for each. Results of performance evaluation on the water quality were expressed in three groups: hydraulic, geotechnical, and economic performance. Results of the analyses of hydraulic indicators showed that the tide phenomenon has a significant impact on the water quality of the SAR. The geotechnical performance was assessed in terms of soil layers and was satisfactory. Analysis of the economic performance indicators showed that the inflatable rubber dam was feasible for the SAR problem compared with other types. Finally, a proposed design indicates the viability of inflatable rubber dam technology in controlling the salt front and improving the quality of the Shatt Al-Arab River water by reducing the salinity.","PeriodicalId":17354,"journal":{"name":"Journal of the Mechanical Behavior of Materials","volume":" ","pages":""},"PeriodicalIF":1.8,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47491403","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract The jet grouting method for soil improvement represents an innovative geotechnical alternative for problematic soils when the classic foundations’ designs cannot be appropriate, sustainable solutions for these soils. This study’s methodology was based on producing column models using a low-pressure injection laboratory setup designed and locally manufactured to approximate the field-equipment operation. The setup design was inspired by the works of previous researchers, where its functioning was validated by systematically performing unconfined compression tests (UCTs). Two soil improvement techniques were investigated, one by low-pressure injection of a mixture of water and ordinary Portland cement (OPC) with 0.8, 1, and 1.3 W/C ratios. The other type uses silica fume (SF) as a chemical additive with 10% of the cement weight added to the water and cement mix with 1, 1.3, and 1.6 W/C ratios. The study revealed that the UCT results of SF column model samples were higher than those of OPC with an equal W/C ratio. For each binder type, the UCT sample results increase with a decrease in the W/C ratio.
{"title":"Comparison between cement and chemically improved sandy soil by column models using low-pressure injection laboratory setup","authors":"M. S. Mohammed, Samir H. Hussein, M. D. Ahmed","doi":"10.1515/jmbm-2022-0258","DOIUrl":"https://doi.org/10.1515/jmbm-2022-0258","url":null,"abstract":"Abstract The jet grouting method for soil improvement represents an innovative geotechnical alternative for problematic soils when the classic foundations’ designs cannot be appropriate, sustainable solutions for these soils. This study’s methodology was based on producing column models using a low-pressure injection laboratory setup designed and locally manufactured to approximate the field-equipment operation. The setup design was inspired by the works of previous researchers, where its functioning was validated by systematically performing unconfined compression tests (UCTs). Two soil improvement techniques were investigated, one by low-pressure injection of a mixture of water and ordinary Portland cement (OPC) with 0.8, 1, and 1.3 W/C ratios. The other type uses silica fume (SF) as a chemical additive with 10% of the cement weight added to the water and cement mix with 1, 1.3, and 1.6 W/C ratios. The study revealed that the UCT results of SF column model samples were higher than those of OPC with an equal W/C ratio. For each binder type, the UCT sample results increase with a decrease in the W/C ratio.","PeriodicalId":17354,"journal":{"name":"Journal of the Mechanical Behavior of Materials","volume":" ","pages":""},"PeriodicalIF":1.8,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43827903","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract As aggregate material typically comprises 65–75% of concrete volume and has a significant effect on its mechanical properties, aggregate type considerably affects concrete behavior at high temperatures. In this study, 80 concrete cylinders and 60 cubes were cast to investigate the residual strength of normal concrete that contains lightweight expanded clay aggregate (LECA) with different volumetric replacement ratios (0, 10, 20, and 30%) of the coarse aggregate. After the fire flame exposure effect of steady-state temperatures (300, 400, 500, and 600°C), and a sudden cooling process, the mechanical tests (compressive strength, tensile strength, and modulus of elasticity; Ec), as well as mass loss and thermal conductivity, were carried out on the specimens. The results indicate that increasing the LECA content in the mixture leads to better strength retention after exposure to fire. After exposure to a steady-state temperature of 600°C, the amount of decrease in mass, residual compressive and tensile strengths, and the residual amount of Ec were 7.61, 7.5, 7.16, and 6.24%; 57.1, 66.8, 69.8, and 72.0%; 22.4, 32.7, 41.8, and 48.6%;, and 16.0, 22.3, 23.4, and 24.3%, respectively, for the considered volumetric replacement ratios of 0, 10, 20, and 30%. Also, the values of the thermal conductivity were 1.4889, 1.1667, 1.0912, and 1.0410 W/m K, respectively.
{"title":"Effect of lightweight expanded clay aggregate as partial replacement of coarse aggregate on the mechanical properties of fire-exposed concrete","authors":"Alaa H. Abdullah, Shatha D. Mohammed","doi":"10.1515/jmbm-2022-0299","DOIUrl":"https://doi.org/10.1515/jmbm-2022-0299","url":null,"abstract":"Abstract As aggregate material typically comprises 65–75% of concrete volume and has a significant effect on its mechanical properties, aggregate type considerably affects concrete behavior at high temperatures. In this study, 80 concrete cylinders and 60 cubes were cast to investigate the residual strength of normal concrete that contains lightweight expanded clay aggregate (LECA) with different volumetric replacement ratios (0, 10, 20, and 30%) of the coarse aggregate. After the fire flame exposure effect of steady-state temperatures (300, 400, 500, and 600°C), and a sudden cooling process, the mechanical tests (compressive strength, tensile strength, and modulus of elasticity; Ec), as well as mass loss and thermal conductivity, were carried out on the specimens. The results indicate that increasing the LECA content in the mixture leads to better strength retention after exposure to fire. After exposure to a steady-state temperature of 600°C, the amount of decrease in mass, residual compressive and tensile strengths, and the residual amount of Ec were 7.61, 7.5, 7.16, and 6.24%; 57.1, 66.8, 69.8, and 72.0%; 22.4, 32.7, 41.8, and 48.6%;, and 16.0, 22.3, 23.4, and 24.3%, respectively, for the considered volumetric replacement ratios of 0, 10, 20, and 30%. Also, the values of the thermal conductivity were 1.4889, 1.1667, 1.0912, and 1.0410 W/m K, respectively.","PeriodicalId":17354,"journal":{"name":"Journal of the Mechanical Behavior of Materials","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135361934","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Haider M. Owaid, Abeer M. Humad, Majid Al-Gburi, Zainab Abdul Sattar Ghali, Gabrial Sas
Abstract Cement has shaped the modern built environment, but its production generates substantial carbon dioxide emissions. Consequently, there is an urgent need to identify alternative cementitious building materials for sustainable construction. In this study, cement mortars (CMs) were produced by partially replacing cement with nanoclay (NC) and granite dust (GD). The replacement proportions (% by weight of cement) of these materials were 1.5, 3, and 4.5% for NC and 10, 20, and 30% for GD. For mortars containing NC but not GD, the strength was maximized when the NC replacement proportion was 3%. To evaluate the combined effect of partially replacing cement with both NC and GD on the fresh and hardening properties of cement-blended mortars, ternary binder mixtures containing 3% NC together with 10, 20, or 30% GD were prepared, and their workability, bulk density, compressive strength (at 7, 28, and 90 days), and flexural strength were measured. Increasing the content of NC and/or GD reduced the flowability of these mortars relative to that of the reference mortar mix because it increased the content of fine materials. CM containing 3% NC and 10% GD had the highest compressive strength at 7, 28, and 90 days while also having the greatest flexural strength when compared to the control mix. This is most likely due to the high silica and alumina content of NC and GD, as well as their high specific surface area, which would improve the maturity and density of the matrix when compared to cement alone.
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