S. Imbin, S. Dullah, H. Asrah, Paramasivam Suresh Kumar, M. E. Rahman, M. Mannan
Service life of existing reinforced concrete (RC) structures in coastal towns of Sabah has been affected very much. Concrete crack, spalling of concrete cover and reinforcement rusting of RC buildings are seen even within 5 years of construction in Sabah. Hence, in this study a new mix design of concrete grout was developed using locally available materials and investigated under two curing conditions and workability, compressive strength, Accelerated Mortar Bar Test (AMBT), water absorption, volume of permeable voids (VPV), Sorptivity and 90-days salt ponding test were conducted. The compressive strength of concrete grout at the age 90 days was found to be 44.49 N/mm 2 under water curing. It was observed that the percentage of mortar bar length change was below 1% for developed concrete grout. The water absorption of the concrete grout was in between the range of 0.88 % to 3.60 % under two different curing up to the age 90 days. It was also observed that the VPV of concrete was in the range of 0 % to 9.75 and 2.44% to 13.05% under water curing and site curing respectively. It was found that the Sorptivity of the concrete grout under water curing at the age of 28 days is 0.211mm/√min and at the age 90 day are 0.067 mm/√min. The chloride content decreased greatly, 90% after a depth of 15 mm. It was noticed that the site cured samples showed higher chloride contents near surface compared to water cured samples. This investigation suggested that the developed mix design of concrete grout using locally available construction materials can be used for crack repairing of existing RC structures in Sabah. Keywords—Concrete grout, Salt ponding, Sorptivity, Water absorption.
{"title":"Performance of concrete grout under aggressive chloride environment in Sabah","authors":"S. Imbin, S. Dullah, H. Asrah, Paramasivam Suresh Kumar, M. E. Rahman, M. Mannan","doi":"10.5281/ZENODO.1083519","DOIUrl":"https://doi.org/10.5281/ZENODO.1083519","url":null,"abstract":"Service life of existing reinforced concrete (RC) structures in coastal towns of Sabah has been affected very much. Concrete crack, spalling of concrete cover and reinforcement rusting of RC buildings are seen even within 5 years of construction in Sabah. Hence, in this study a new mix design of concrete grout was developed using locally available materials and investigated under two curing conditions and workability, compressive strength, Accelerated Mortar Bar Test (AMBT), water absorption, volume of permeable voids (VPV), Sorptivity and 90-days salt ponding test were conducted. The compressive strength of concrete grout at the age 90 days was found to be 44.49 N/mm 2 under water curing. It was observed that the percentage of mortar bar length change was below 1% for developed concrete grout. The water absorption of the concrete grout was in between the range of 0.88 % to 3.60 % under two different curing up to the age 90 days. It was also observed that the VPV of concrete was in the range of 0 % to 9.75 and 2.44% to 13.05% under water curing and site curing respectively. It was found that the Sorptivity of the concrete grout under water curing at the age of 28 days is 0.211mm/√min and at the age 90 day are 0.067 mm/√min. The chloride content decreased greatly, 90% after a depth of 15 mm. It was noticed that the site cured samples showed higher chloride contents near surface compared to water cured samples. This investigation suggested that the developed mix design of concrete grout using locally available construction materials can be used for crack repairing of existing RC structures in Sabah. Keywords—Concrete grout, Salt ponding, Sorptivity, Water absorption.","PeriodicalId":90395,"journal":{"name":"World academy of science, engineering and technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2013-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79256098","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}
Pub Date : 2011-02-01DOI: 10.5369/jsst.2013.22.4.239
Keun-soo Lee, Kyongsoo Lee, V. W. Lau, K. Shin, B. Ju
Abstract Several methods are available to measure the oxidation of edible oils, such as their acid, peroxide, and anisidine values. However, thesemethods require large quantities of reagents and are time-consuming tasks. Therefore, a more convenient and time-saving way to measurethe oxidation of edible oils is required. In this study, an edible oil-condition sensor was fabricated using single-walled nanotubes(SWNTs) made using the spray deposition method. SWNTs were dispersed in a dimethylformamide solution. The suspension was thensprayed using a spray gun onto a prefabricated Au/Ti electrode. To test the sensor, oxidized edible oils, each with a different acid value,were prepared. The SWNT sensors were immersed into these oxidized oils, and the resistance changes in the sensors were measured. Wefound that the conductivity of the sensors decreased as the oxidation level of the oil increased. In the case of the virgin oil, the resistancechange ratio in the SWNT sensor S(%) = {[(Rf _ Ri)]/Ri}(%) was more than 40% after immersion for 1 min. However, in the case of theoxidized oil, the resistance change ratio decreased to less than that of the response of the virgin oil. This result suggests that the change inthe oil components induced by the oxidation process in edible oils is related to the conductivity change in the SWNT sensor.
{"title":"SWNT sensors for monitoring the oxidation of edible oils","authors":"Keun-soo Lee, Kyongsoo Lee, V. W. Lau, K. Shin, B. Ju","doi":"10.5369/jsst.2013.22.4.239","DOIUrl":"https://doi.org/10.5369/jsst.2013.22.4.239","url":null,"abstract":"Abstract Several methods are available to measure the oxidation of edible oils, such as their acid, peroxide, and anisidine values. However, thesemethods require large quantities of reagents and are time-consuming tasks. Therefore, a more convenient and time-saving way to measurethe oxidation of edible oils is required. In this study, an edible oil-condition sensor was fabricated using single-walled nanotubes(SWNTs) made using the spray deposition method. SWNTs were dispersed in a dimethylformamide solution. The suspension was thensprayed using a spray gun onto a prefabricated Au/Ti electrode. To test the sensor, oxidized edible oils, each with a different acid value,were prepared. The SWNT sensors were immersed into these oxidized oils, and the resistance changes in the sensors were measured. Wefound that the conductivity of the sensors decreased as the oxidation level of the oil increased. In the case of the virgin oil, the resistancechange ratio in the SWNT sensor S(%) = {[(Rf _ Ri)]/Ri}(%) was more than 40% after immersion for 1 min. However, in the case of theoxidized oil, the resistance change ratio decreased to less than that of the response of the virgin oil. This result suggests that the change inthe oil components induced by the oxidation process in edible oils is related to the conductivity change in the SWNT sensor.","PeriodicalId":90395,"journal":{"name":"World academy of science, engineering and technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73060672","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}
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