Publications (2)0 Total impact
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Article: Optimization of discharge condition for recycling aggregate by pulsed discharge inside of concrete
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ABSTRACT: The development of a new recycling technology for waste concrete scraps becomes a big issue in Japan due to the increase of the scraps and the decrease of the natural coarse aggregates. In the present work, a new technology of concrete aggregates recycling using pulsed discharges was performed. A Marx generator was used as a pulsed power source and a point to hemisphere mesh configuration electrode was immersed in water. The pulsed voltages were applied to the concrete scraps which placed on hemisphere mesh and the discharges passes were occurred inside of concrete scraps as the result of the electrical breakdown. Immediately after the breakdown, the concrete scraps were broken by the shockwave due to the volumetric thermal expansion of the discharge pass. After the repetitive discharge treatments, the recycled coarse aggregates were evaluated. From our previous results, the quality of the recycled coarse aggregates such as the oven-dry density, the water absorption ratio, and the fineness modulus were controlled by the energy consumption of discharge treatments. In this work, the effects of the gap distance between high voltage point electrode and concrete surface was discussed. The results showed that the optimum condition was obtained in case that the high voltage point electrode always comes in contact with the target concrete.01/2009; -
Conference Proceeding: Evaluation of concrete made from recycled coarse aggregates by pulsed power discharge
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ABSTRACT: In Japan, the most of waste concrete scraps have been reused as roadbed materials and the recycling ratio of waste concrete scraps has been kept over 95 % from 2000. However, it is expected that the demands of waste concrete scraps as roadbed materials would decrease even though the waste concrete scraps increase with the pulling down buildings in next decade. These facts mean that the recycling of waste concrete scraps would be in the negative situation. Therefore, the development of new recycling technology of waste concrete scraps is paramount importance in Japan. In this work, the pulsed power discharges inside of waste concrete scraps immersed in water were used to reproduce the coarse aggregate. In the experiments, the Marx generator, which storages the energy of 6.4 kJ/Pulse, was used as pulsed power source and the point to hemisphere mesh electrode was immersed in water. The pulsed voltages with 400 kV of peak voltage were applied to the concrete scraps placed on hemisphere mesh and the reproduced coarse aggregates were evaluated after the repetitive discharge treatment. From the experimental results, it is found that the coarse aggregates reproduced by 40∼60 pulsed discharge treatments have the enough qualities of the bone-dry density and the water absorption rate to satisfy JIS (Japan Industrial Standard) regulation (A 5005). In addition, the concretes consisted of the reproduced coarse aggregate also have the enough compressed strength and Young’s module to utilize as the construction material.Pulsed Power Conference, 2007 16th IEEE International; 07/2007 -
Article: Evaluation of Concrete Made from Recycled Coarse Aggregates by Pulsed Power Discharge
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ABSTRACT: In Japan, the most of waste concrete scraps have been reused as roadbed materials and the recycling ratio of waste concrete scraps has been kept over 95 % from 2000. However, it is expected that the demands of waste concrete scraps as roadbed materials would decrease even though the waste concrete scraps increase with the pulling down buildings in next decade. These facts mean that the recycling of waste concrete scraps would be in the negative situation. Therefore, the development of new recycling technology of waste concrete scraps is paramount importance in Japan. In this work, the pulsed power discharges inside of waste concrete scraps immersed in water were used to reproduce the coarse aggregate. In the experiments, the Marx generator, which storages the energy of 6.4 kJ/Pulse, was used as pulsed power source and the point to hemisphere mesh electrode was immersed in water. The pulsed voltages with 400 kV of peak voltage were applied to the concrete scraps placed on hemisphere mesh and the reproduced coarse aggregates were evaluated after the repetitive discharge treatment. From the experimental results, it is found that the coarse aggregates reproduced by 40~60 pulsed discharge treatments have the enough qualities of the bone-dry density and the water absorption rate to satisfy JIS (Japan Industrial Standard) regulation (A 5005). In addition, the concretes consisted of the reproduced coarse aggregate also have the enough compressed strength and Young’s module to utilize as the construction material. -
Article: Evaluation of Concrete Made from Recycled Coarse Aggregates by Poulsed Power Discharge Treatments
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ABSTRACT: Summary form only given. In Japan, the most of waste concrete scraps have been reused as roadbed materials and the recycling ratio of waste concrete scraps has been kept over 95% from 2000. However, it is expected that the demands of waste concrete scraps as roadbed materials would decreases even though the waste concrete scraps increase with the pulling down buildings in next decade. These mean that the recycling of waste concrete scraps would be in the negative situation. Therefore, the development of new recycling technology of waste concrete scraps is paramount importance in Japan. In this work, the pulsed power discharges inside of waste concrete scraps immersed in water were used to reproduce the coarse aggregate. In the experiments, the Marx generator, which storages the energy of 6.4 kJ/Pulse, was used as pulsed power source and the point to hemisphere mesh electrode was immersed in water. The pulsed voltages with 400 kV of peak voltage were applied to the concrete scraps placed on hemisphere mesh and the reproduced coarse aggregates were evaluated after the repetitive discharge treatment. From the experimental results, it is found that the coarse aggregates reproduced by 80 pulsed discharge treatments have the enough qualities of the bone dry density and the water absorption ratio to satisfy JIS (Japan Industrial Standard) regulation (A 5005). In addition, the concretes consisted of the reproduced coarse aggregate also have the enough compressed strength and Young's module to utilize as the construction material.
