This research investigates the physical property and durability of CLSM (Controlled Low Strength Materials) made with used foundry sand and bottom ash as fine aggregates. These materials are industrial by-product and non-standard materials. The effect of mixture proportions on the compressive strength and the frost heaving resistance of CLSM is evaluated for application to cold regions. A wide range of used foundry sand or bottom ash additions were evaluated in order to provide a cost-effective mixture proportion for various material costs. A total of 26 mixtures were tested in this study. Test results show the applicability of used foundry sand as well as a wide range of different bottom ashes substituting for the fine aggregates. Optimum addition of used foundry sand, and bottom ash to fly ash was found. Long-term strength developments of various types of mixtures were observed. The frost heaving rate of CLSM with used foundry sand and bottom ash was measured and showed less than 3%, which is a relatively smaller value compare to soil like materials. However, some of the specimens were found to have visible cracks. Further research will be needed for evaluating the CLSM durability against frost heaving actions.
{"title":"\"Durability of CLSM with Used Foundry Sand, Bottom Ash, and Fly Ash in Cold Regions\"","authors":"T. Horiguchi, H. Okumara, N. Saeki","doi":"10.14359/10587","DOIUrl":"https://doi.org/10.14359/10587","url":null,"abstract":"This research investigates the physical property and durability of CLSM (Controlled Low Strength Materials) made with used foundry sand and bottom ash as fine aggregates. These materials are industrial by-product and non-standard materials. The effect of mixture proportions on the compressive strength and the frost heaving resistance of CLSM is evaluated for application to cold regions. A wide range of used foundry sand or bottom ash additions were evaluated in order to provide a cost-effective mixture proportion for various material costs. A total of 26 mixtures were tested in this study. Test results show the applicability of used foundry sand as well as a wide range of different bottom ashes substituting for the fine aggregates. Optimum addition of used foundry sand, and bottom ash to fly ash was found. Long-term strength developments of various types of mixtures were observed. The frost heaving rate of CLSM with used foundry sand and bottom ash was measured and showed less than 3%, which is a relatively smaller value compare to soil like materials. However, some of the specimens were found to have visible cracks. Further research will be needed for evaluating the CLSM durability against frost heaving actions.","PeriodicalId":184301,"journal":{"name":"\"SP-200: Fifth CANMET/ACI Conference on Recent Advances in Concrete Technology-Proceeding, Fifth International Conference\"","volume":"86 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115155964","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}
The paper presents an experimental study on the performance of steel-reinforced concrete (STC) joints under reversal cyclic loads. Five composite joint specimens comprising built-up steel-reinforced concrete columns connecting to reinforced concrete (RC) beams were tested to failure. Three modes of failure were observed. They are: (1) bending failure in beam, (2) bending-shear failure in beam and (3) shear failure in beam and joint. Test results indicated that energy absorption capacity of the SRC joint depends on the modes of failure as well as the levels of axial load imposed on the column. The latter also influences the shear capacity of the joint.
{"title":"Experimental Study on Behavior of Steel-Reinforced Concrete Joints","authors":"S. Swaddiwudhipong, D. Jiang","doi":"10.14359/10610","DOIUrl":"https://doi.org/10.14359/10610","url":null,"abstract":"The paper presents an experimental study on the performance of steel-reinforced concrete (STC) joints under reversal cyclic loads. Five composite joint specimens comprising built-up steel-reinforced concrete columns connecting to reinforced concrete (RC) beams were tested to failure. Three modes of failure were observed. They are: (1) bending failure in beam, (2) bending-shear failure in beam and (3) shear failure in beam and joint. Test results indicated that energy absorption capacity of the SRC joint depends on the modes of failure as well as the levels of axial load imposed on the column. The latter also influences the shear capacity of the joint.","PeriodicalId":184301,"journal":{"name":"\"SP-200: Fifth CANMET/ACI Conference on Recent Advances in Concrete Technology-Proceeding, Fifth International Conference\"","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115475267","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}
In recent years, increasing efforts have been geared toward enhancing the axial load-carrying capacity of wall-like (i.e. high aspect ratio) reinforced concrete columns commonly used in building estates in Singapore. Although it has been proven through experimental results that composite fiber wraps are effective in strengthening round and square columns by providing passive confinement pressure to the core concrete, wall-like columns experience less effect from confinement, which is limited to the corners. In addition, published research work on wall-like column strengthening did not consider the effects of sustained loading during the application of the fiber reinforced polymer. Consequently, the present study explores an alternative strengthening scheme that employs other materials in addition to composite sheets and will investigate the effects of sustained loading on the strengthening efficiency.
{"title":"Strengthening of RC Wall-like Columns","authors":"S. Tanwongsval, M. Maalej, P. Paramasivam","doi":"10.14359/10608","DOIUrl":"https://doi.org/10.14359/10608","url":null,"abstract":"In recent years, increasing efforts have been geared toward enhancing the axial load-carrying capacity of wall-like (i.e. high aspect ratio) reinforced concrete columns commonly used in building estates in Singapore. Although it has been proven through experimental results that composite fiber wraps are effective in strengthening round and square columns by providing passive confinement pressure to the core concrete, wall-like columns experience less effect from confinement, which is limited to the corners. In addition, published research work on wall-like column strengthening did not consider the effects of sustained loading during the application of the fiber reinforced polymer. Consequently, the present study explores an alternative strengthening scheme that employs other materials in addition to composite sheets and will investigate the effects of sustained loading on the strengthening efficiency.","PeriodicalId":184301,"journal":{"name":"\"SP-200: Fifth CANMET/ACI Conference on Recent Advances in Concrete Technology-Proceeding, Fifth International Conference\"","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116513616","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}
The maturity approach has been used conventionally to model temperature effects on the development of concrete compressive strength. Its application to concrete technology, however, goes far beyond simply estimating compressive strength. When the maturity approach is based on cement hydration kinetics, it can be applied to any concrete property related to the extent of cement hydration. In this study, the application of the maturity approach to model the development of various concrete properties was investigated. In addition to compressive strength, other properties evaluated included degree of hydration and ultrasonic pulse velocity. Hyperbolic equations were investigated for the development of each model. Different values of apparent activation energies were calculated according to the procedure in ASTM C 1074. It was concluded that activation energy is an indication of the thermal sensitivity of the concrete property investigated. The calculated value of activation energy depends on the specific property and the maturity model used.
成熟度法通常用于模拟温度对混凝土抗压强度发展的影响。然而，它在混凝土技术中的应用远远超出了简单地估计抗压强度。当成熟度法基于水泥水化动力学时，它可以应用于与水泥水化程度有关的任何混凝土性能。在本研究中，研究了成熟度法在混凝土各种性能发展模型中的应用。除抗压强度外，评估的其他性能包括水化程度和超声波脉冲速度。每个模型的发展都采用了双曲方程。根据ASTM C 1074的程序计算了不同的表观活化能值。结果表明，活化能是表征所研究混凝土性能的热敏性指标。活化能的计算值取决于具体的性质和所用的成熟度模型。
{"title":"The Maturity Approach in Concrete Technology-Going Beyond Compressive Strength","authors":"R. Pinto, S. Hobbs, K. Hover","doi":"10.14359/10613","DOIUrl":"https://doi.org/10.14359/10613","url":null,"abstract":"The maturity approach has been used conventionally to model temperature effects on the development of concrete compressive strength. Its application to concrete technology, however, goes far beyond simply estimating compressive strength. When the maturity approach is based on cement hydration kinetics, it can be applied to any concrete property related to the extent of cement hydration. In this study, the application of the maturity approach to model the development of various concrete properties was investigated. In addition to compressive strength, other properties evaluated included degree of hydration and ultrasonic pulse velocity. Hyperbolic equations were investigated for the development of each model. Different values of apparent activation energies were calculated according to the procedure in ASTM C 1074. It was concluded that activation energy is an indication of the thermal sensitivity of the concrete property investigated. The calculated value of activation energy depends on the specific property and the maturity model used.","PeriodicalId":184301,"journal":{"name":"\"SP-200: Fifth CANMET/ACI Conference on Recent Advances in Concrete Technology-Proceeding, Fifth International Conference\"","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125995665","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}
The feasibility of using crushed post-consumer glass as a partial replacement of sand in concrete has been studied. To suppress the deleterious reaction between the alkali in cement and the silica in crushed post-consumer glass (ASR), a Class F fly ash was used in the experiment with the cement replacements of about 15, 30, and 45 percent by mass using a ratio of fly ash inclusion to cement replaced of about 1.25. Therefore, actual fly ash to total cementitious materials ratio was 18, 35, and 51 by mass. For each combination of cement and fly ash, 15%, 30%, and 45% volume of SSD sand were replaced with crushed glass. The compressive strength and splitting tensile strength of concrete were determined at specified ages for each mixture. Alkali silica reaction was evaluated according to ASTM C 1260 (Mortar Bar Method). Test results indicate that both compressive strength and splitting tensile strength of concrete decrease slightly with an increase in the replacement rate of sand with crushed glass. At lower replacement rates (less than 45%), the Class F fly ash could only delay the onset of expansion, while with high amount of fly ash concrete was immune to ASR.
研究了用破碎的消费后玻璃代替混凝土中部分砂石的可行性。为了抑制水泥中的碱与破碎后消费玻璃(ASR)中的二氧化硅之间的有害反应，实验中使用了F级粉煤灰，水泥替代量分别为15%、30%和45%，粉煤灰包合物与替代水泥的比例约为1.25。因此，实际粉煤灰与总胶凝材料的质量比分别为18、35和51。对于水泥和粉煤灰的每种组合，用碎玻璃代替15%、30%和45%体积的SSD砂。测定了每种混合料在指定龄期混凝土的抗压强度和劈裂抗拉强度。根据ASTM C 1260(砂浆棒法)对碱硅反应进行评价。试验结果表明，混凝土的抗压强度和劈裂抗拉强度均随砂与碎玻璃替换率的增加而略有下降。在较低的替换率下(小于45%)，F类粉煤灰只能延缓膨胀的开始，而高掺量的粉煤灰混凝土则不受ASR的影响。
{"title":"Crushed Post-Consumer Glass as Partial Replacement of Sand in Concrete","authors":"T. Naik, Z. Wu","doi":"10.14359/10601","DOIUrl":"https://doi.org/10.14359/10601","url":null,"abstract":"The feasibility of using crushed post-consumer glass as a partial replacement of sand in concrete has been studied. To suppress the deleterious reaction between the alkali in cement and the silica in crushed post-consumer glass (ASR), a Class F fly ash was used in the experiment with the cement replacements of about 15, 30, and 45 percent by mass using a ratio of fly ash inclusion to cement replaced of about 1.25. Therefore, actual fly ash to total cementitious materials ratio was 18, 35, and 51 by mass. For each combination of cement and fly ash, 15%, 30%, and 45% volume of SSD sand were replaced with crushed glass. The compressive strength and splitting tensile strength of concrete were determined at specified ages for each mixture. Alkali silica reaction was evaluated according to ASTM C 1260 (Mortar Bar Method). Test results indicate that both compressive strength and splitting tensile strength of concrete decrease slightly with an increase in the replacement rate of sand with crushed glass. At lower replacement rates (less than 45%), the Class F fly ash could only delay the onset of expansion, while with high amount of fly ash concrete was immune to ASR.","PeriodicalId":184301,"journal":{"name":"\"SP-200: Fifth CANMET/ACI Conference on Recent Advances in Concrete Technology-Proceeding, Fifth International Conference\"","volume":"122 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133883795","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}
In 1986, as part of CANMET's on-going program on the long-term durability of concrete in marine environment, twelve concrete panels, each 3.7 meters long, were installed at a site at Nanisivik (Latitude 73 degrees North), Baffin Island, North West Territories, Canada. Six of the panels were made with normal-weight aggregate concrete, and the other six panels were made with concrete incorporating expanded shale lightweight aggregate. Other variables in the concrete mixtures included steel fibers, and the replacement of portland cement by fly ash, slag, silica fume, or a combination of fly ash and silica fume. The cement replacement levels used ranges from 10% for silica fume to 50% for ground granulated blast-furnace slag. The water-to-cementitious materials ratio of all these concretes ranged from 0.37 to 0.42. In 1996, visual examination was made and cores were taken from the concrete panels to determine the chloride content at various depths from the exposure surface. After 10 years of exposure in the Arctic marine environment, the panels made with normal weight aggregate showed very little mass loss on the surface due to ice abrasion, whereas panels made with lightweight aggregate seems to have some mass loss on the surface exposed to the tidal zone. The steel fiber-reinforced panels appear to have less damage and cracking than the corresponding ones without fibers. Concrete incorporating supplementary cementing materials such as fly ash, silica fume, slag, or a combination of fly ash and silica fume generally had better resistance to the penetration of chloride ions compared with corresponding control portland cement concrete of similar water-to-cementitious materials ratio. In general, the concentration of chloride ions in fiber-reinforced concrete was similar to or lower than those of the corresponding non-fiber-reinforced concrete exposed. For the non-fiber-reinforced portland cement concrete, the use of either normal weight limestone aggregate or expanded shale lightweight aggregate did not seem to significantly affect the resistance of the concrete to the chloride-ion penetration. However, fiber-reinforced portland cement concrete made with lightweight aggregate appears to have lower chloride-ion content than that made with normal weight aggregate.
{"title":"Performance of Concrete After Ten Years of Exposure in the Arctic Marine Environment","authors":"Min-hong Zhang, A. Bilodeau, V. Malhotra","doi":"10.14359/10606","DOIUrl":"https://doi.org/10.14359/10606","url":null,"abstract":"In 1986, as part of CANMET's on-going program on the long-term durability of concrete in marine environment, twelve concrete panels, each 3.7 meters long, were installed at a site at Nanisivik (Latitude 73 degrees North), Baffin Island, North West Territories, Canada. Six of the panels were made with normal-weight aggregate concrete, and the other six panels were made with concrete incorporating expanded shale lightweight aggregate. Other variables in the concrete mixtures included steel fibers, and the replacement of portland cement by fly ash, slag, silica fume, or a combination of fly ash and silica fume. The cement replacement levels used ranges from 10% for silica fume to 50% for ground granulated blast-furnace slag. The water-to-cementitious materials ratio of all these concretes ranged from 0.37 to 0.42. In 1996, visual examination was made and cores were taken from the concrete panels to determine the chloride content at various depths from the exposure surface. After 10 years of exposure in the Arctic marine environment, the panels made with normal weight aggregate showed very little mass loss on the surface due to ice abrasion, whereas panels made with lightweight aggregate seems to have some mass loss on the surface exposed to the tidal zone. The steel fiber-reinforced panels appear to have less damage and cracking than the corresponding ones without fibers. Concrete incorporating supplementary cementing materials such as fly ash, silica fume, slag, or a combination of fly ash and silica fume generally had better resistance to the penetration of chloride ions compared with corresponding control portland cement concrete of similar water-to-cementitious materials ratio. In general, the concentration of chloride ions in fiber-reinforced concrete was similar to or lower than those of the corresponding non-fiber-reinforced concrete exposed. For the non-fiber-reinforced portland cement concrete, the use of either normal weight limestone aggregate or expanded shale lightweight aggregate did not seem to significantly affect the resistance of the concrete to the chloride-ion penetration. However, fiber-reinforced portland cement concrete made with lightweight aggregate appears to have lower chloride-ion content than that made with normal weight aggregate.","PeriodicalId":184301,"journal":{"name":"\"SP-200: Fifth CANMET/ACI Conference on Recent Advances in Concrete Technology-Proceeding, Fifth International Conference\"","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131466992","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}
The use of high-strength concrete in precast factories is a common solution to attain larger spans and columns with a higher load bearing capacity. Taking into account the cost for transforming the mold turnover in the precast line, it is economical to alter the concrete composition and the amount and size of reinforcement to attain the higher requirements. In collaboration with a precast factory, a test program was carried out to reveal the influence of concrete composition and curing temperature on material properties. The goal of the project was to predict the strength evolution of the material, using conventional maturity functions. Therefore, different concrete compositions were used, varying from concretes normally used on construction site, to high-strength concrete. Different curing temperatures were considered. The paper presents the evolution of the compressive strength in time, taking into account different parameters as well as the evaluation of existing maturity functions. Among others, the maturity functions of Plowman, of Kee, of Freiesleben-Hansen and Pedersen and of Carino are investigated. Especially the model, proposed by Carino predicted the strength evolution adequately.
{"title":"The Effect of Curing Temperature on High-Strength Concrete Used in Precast Factories","authors":"A. Beeldens, L. Vandewalle","doi":"10.14359/10571","DOIUrl":"https://doi.org/10.14359/10571","url":null,"abstract":"The use of high-strength concrete in precast factories is a common solution to attain larger spans and columns with a higher load bearing capacity. Taking into account the cost for transforming the mold turnover in the precast line, it is economical to alter the concrete composition and the amount and size of reinforcement to attain the higher requirements. In collaboration with a precast factory, a test program was carried out to reveal the influence of concrete composition and curing temperature on material properties. The goal of the project was to predict the strength evolution of the material, using conventional maturity functions. Therefore, different concrete compositions were used, varying from concretes normally used on construction site, to high-strength concrete. Different curing temperatures were considered. The paper presents the evolution of the compressive strength in time, taking into account different parameters as well as the evaluation of existing maturity functions. Among others, the maturity functions of Plowman, of Kee, of Freiesleben-Hansen and Pedersen and of Carino are investigated. Especially the model, proposed by Carino predicted the strength evolution adequately.","PeriodicalId":184301,"journal":{"name":"\"SP-200: Fifth CANMET/ACI Conference on Recent Advances in Concrete Technology-Proceeding, Fifth International Conference\"","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130738249","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}
The authors have studied the effects of autoclaving under saturated vapor at 180 degrees C on the physical and mechanical properties of reactive-powder mortars reinforced with brass coated steel fibers. The system consisted of portland cement (ASTM Type V), silica fume, natural silica sand (maximum grain size<1mm), an acrylic super-plasticizer, and brass coated steel fibers (L=13mm, theta=0.18mm); a water-to-cement of 0.255 was used to obtain a flowable system. Specimens were subjected to high pressure steam curing for 3 hours after preliminary curing at normal temperatures and for different times. Samples pre-cured at normal temperature for 24 hours and 3 days were autoclaved for up to 12 hours. Autoclaving generally produced beneficial effects on the mechanical properties, both in terms of flexural and compressive strength. High pressure steam curing for 3 hours of specimens pre-cured at ambient temperature for 3 days yielded flexural strength of 30 MPa and compressive strength of 200 MPa. The strengthening mechanisms depend only in part on the greater degree of hydration as the hydrated phases that form in the systems prepared with low water/cement are highly impermeable. The main effect appears to be the result of modifications to the microstructure that manifests itself as a reduction in porosity and hence in better mechanical properties.
{"title":"High Pressure Steam Curing of Reactive-Powder Mortars","authors":"L. Massidda, U. Sanna, E. Cocco, P. Meloni","doi":"10.14359/10594","DOIUrl":"https://doi.org/10.14359/10594","url":null,"abstract":"The authors have studied the effects of autoclaving under saturated vapor at 180 degrees C on the physical and mechanical properties of reactive-powder mortars reinforced with brass coated steel fibers. The system consisted of portland cement (ASTM Type V), silica fume, natural silica sand (maximum grain size<1mm), an acrylic super-plasticizer, and brass coated steel fibers (L=13mm, theta=0.18mm); a water-to-cement of 0.255 was used to obtain a flowable system. Specimens were subjected to high pressure steam curing for 3 hours after preliminary curing at normal temperatures and for different times. Samples pre-cured at normal temperature for 24 hours and 3 days were autoclaved for up to 12 hours. Autoclaving generally produced beneficial effects on the mechanical properties, both in terms of flexural and compressive strength. High pressure steam curing for 3 hours of specimens pre-cured at ambient temperature for 3 days yielded flexural strength of 30 MPa and compressive strength of 200 MPa. The strengthening mechanisms depend only in part on the greater degree of hydration as the hydrated phases that form in the systems prepared with low water/cement are highly impermeable. The main effect appears to be the result of modifications to the microstructure that manifests itself as a reduction in porosity and hence in better mechanical properties.","PeriodicalId":184301,"journal":{"name":"\"SP-200: Fifth CANMET/ACI Conference on Recent Advances in Concrete Technology-Proceeding, Fifth International Conference\"","volume":"172 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132994815","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}
B. Dorsthorst, A. Fraaij, T. Kowalczyk, G. Sluimer
One of the main problems of sustainable building is that the existing systems don't lead to clean and direct reusable secondary building materials after demolition. In constructions in the Netherlands many different building materials are being used. When a building has reached its end of life, it will be demolished and it becomes demolition waste. Because a lot of different building materials will be mixed together during the demolition process, much effort must be taken before the demolition and construction waste can be reused. To solve this problem, two steps need to be taken. Firstly, a building should be designed for recycling. Secondly, all buildings should be dismantled into elements or reduced to clean secondary materials. The approach here is twofold. Firstly, research into the demolition/dismantling-process is conducted in order to find the bottlenecks in closing of the material cycle (at either element or material level). Secondly, as a spin-off of solving these problems, recommendations are made for future building-systems: design for recycling. This paper describes how certain demolition and dismantling techniques can be used in achieving the goals of sustainable design and construction.
{"title":"From Grave to Cradle: Reincarnation of Building Materials","authors":"B. Dorsthorst, A. Fraaij, T. Kowalczyk, G. Sluimer","doi":"10.14359/10572","DOIUrl":"https://doi.org/10.14359/10572","url":null,"abstract":"One of the main problems of sustainable building is that the existing systems don't lead to clean and direct reusable secondary building materials after demolition. In constructions in the Netherlands many different building materials are being used. When a building has reached its end of life, it will be demolished and it becomes demolition waste. Because a lot of different building materials will be mixed together during the demolition process, much effort must be taken before the demolition and construction waste can be reused. To solve this problem, two steps need to be taken. Firstly, a building should be designed for recycling. Secondly, all buildings should be dismantled into elements or reduced to clean secondary materials. The approach here is twofold. Firstly, research into the demolition/dismantling-process is conducted in order to find the bottlenecks in closing of the material cycle (at either element or material level). Secondly, as a spin-off of solving these problems, recommendations are made for future building-systems: design for recycling. This paper describes how certain demolition and dismantling techniques can be used in achieving the goals of sustainable design and construction.","PeriodicalId":184301,"journal":{"name":"\"SP-200: Fifth CANMET/ACI Conference on Recent Advances in Concrete Technology-Proceeding, Fifth International Conference\"","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116287203","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}
J. Lau, K. Tan, L. Oh, C. K. Tan, K. Ong, S. Sabesan
Normal portland cement concrete is the most widely used material in the construction industry in Singapore. Under normal curing conditions, it can take one day or more before the concrete can be safely handled without damage. In precast production, it is desirable for the concrete to attain sufficient strength within a short period of time so that moulds and other resources can be used more efficiently. A revolutionary method of curing using microwave heating utilizes the internal energy dissipation associated with the excitation of molecular dipoles in electromagnetic fields. This method enables faster and more uniform heating and has been found to shorten the process time necessary to achieve high early strength. At present, the use of microwave curing on an industrial scale is still in its infancy. The Prefabrication Technologly Centre in Singapore has developed the first prototype mechanized industrial microwave curing system in this region. This paper will discuss the use of this system for the production of ferrocement secondary roofing slabs on an industrial scale. It is believed that this technology has great potential to revolutionize curing of precast concrete.
{"title":"Microwave Accelerated Production of Ferrocement Slabs-An Industrial Perspective","authors":"J. Lau, K. Tan, L. Oh, C. K. Tan, K. Ong, S. Sabesan","doi":"10.14359/10599","DOIUrl":"https://doi.org/10.14359/10599","url":null,"abstract":"Normal portland cement concrete is the most widely used material in the construction industry in Singapore. Under normal curing conditions, it can take one day or more before the concrete can be safely handled without damage. In precast production, it is desirable for the concrete to attain sufficient strength within a short period of time so that moulds and other resources can be used more efficiently. A revolutionary method of curing using microwave heating utilizes the internal energy dissipation associated with the excitation of molecular dipoles in electromagnetic fields. This method enables faster and more uniform heating and has been found to shorten the process time necessary to achieve high early strength. At present, the use of microwave curing on an industrial scale is still in its infancy. The Prefabrication Technologly Centre in Singapore has developed the first prototype mechanized industrial microwave curing system in this region. This paper will discuss the use of this system for the production of ferrocement secondary roofing slabs on an industrial scale. It is believed that this technology has great potential to revolutionize curing of precast concrete.","PeriodicalId":184301,"journal":{"name":"\"SP-200: Fifth CANMET/ACI Conference on Recent Advances in Concrete Technology-Proceeding, Fifth International Conference\"","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130760635","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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