The presence of waste tires poses an environmental challenge as they occupy a significant amount of land and are expensive to dispose in landfills.However,reusing waste tires can address this issue when waste tires ar...The presence of waste tires poses an environmental challenge as they occupy a significant amount of land and are expensive to dispose in landfills.However,reusing waste tires can address this issue when waste tires are used in geotechnical applications.To determine the viability of this approach,laboratoryscale tests were conducted to investigate load-bearing capacity of circular footings on sand-tire shred(STS)mixtures with shredded waste tire contents of 5%e15%by weight and three different widths of shreds.The investigation focused on analyzing the thickness of layers composed of STS mixtures,the soil cap,and the impact of geogrids on bearing capacity.The results indicate that a specific mixture of sand and tire shreds provides the highest footing-bearing capacity.In addition,the optimal shred content and size were found to be 10%by weight and 2 cm×10 cm,respectively.Furthermore,for a given tire shred width,a particular length provides the largest bearing capacity.The results agree well with that of previous research conducted by the first author and his colleagues in direct shear and California bearing ratio(CBR)tests.The primary finding of this research is that the use of two-layered STS mixtures reinforced by geogrids significantly enhances the bearing capacity.展开更多
The performance of a well-designed layer of sand, and composites like layer of sand mixed with shredded rubber tire (RSM) as low cost base isolators, is studied in shake table tests in the laboratory. The building fou...The performance of a well-designed layer of sand, and composites like layer of sand mixed with shredded rubber tire (RSM) as low cost base isolators, is studied in shake table tests in the laboratory. The building foundation is modeled by a 200 mm by 200 mm and 40 mm thick rigid plexi-glass block. The block is placed in the middle of a 1m by 1m tank filled with sand. The selected base isolator is placed between the block and the sand foundation. Accelerometers are placed on top of the footing and foundation sand layer. The displacement of the footing is also measured by LVDT. The whole setup is mounted on a shake table and subjected to sinusoidal motions with varying amplitude and frequency. Sand is found to be effective only at very high amplitude (> 0.65 g) of motions. The performance of a composite consisting of sand and 50% shredded rubber tire placed under the footing is found to be most promising as a low-cost effective base isolator.展开更多
Microbial-induced carbonate precipitation(MICP)technique has been adopted in geotechnical engineering widely.In this study,the effect of drying-wetting cycles on MICP-recycled shredded coconut coir(RSC)reinforced calc...Microbial-induced carbonate precipitation(MICP)technique has been adopted in geotechnical engineering widely.In this study,the effect of drying-wetting cycles on MICP-recycled shredded coconut coir(RSC)reinforced calcareous sand was studied,and the deterioration mechanism under drying-wetting cycles was revealed.Test results indicated that drying-wetting cycles exert an important influence on the durability of MICP-RSC reinforced specimens.With the increase of drying-wetting cycles N,the specimens demonstrated significant increase in mass loss rate and critical void ratio,decrease in maximum shear modulus,peak strength and toughness.Furthermore,an increase in the initial relative density reduced the deterioration of MICP-RSC reinforced specimens exposed to drying-wetting cycles.Higher initial relative density of the specimen correlates with an increased maximum shear modulus,peak stress and toughness,a decreased in permeability and critical void ratio.Microanalysis revealed that the generated calcium carbonate adhering to sand particles and RSC gradually dropped off with the increase of N,weakened cementation,and led to the deterioration of MICP-RSC reinforced specimens,which is consistent with the deterioration characteristics under drying-wetting cycles.展开更多
Electronic scrap, especially wasted printed circuit boards (PCBs), is regarded as an environmental challenge. At present, the physical separation is thought to be the environmental friendly and economical method of tr...Electronic scrap, especially wasted printed circuit boards (PCBs), is regarded as an environmental challenge. At present, the physical separation is thought to be the environmental friendly and economical method of treating and reutilizing electronic waste. An effective liberation of metals from non metallic components is a crucial step towards mechanical separation and recycling of wasted PCBs. In this paper, the selective shredding theory and mechanics characteristics of wasted PCBs were analyzed, and the shredded experiments of wasted PCBs by hammer mill were investigated. The result shows that the selective shredding exists in the wasted PCBs shredded process by hammer mill. The shredding velocity of non metallic components is far greater than that of metals in the wasted PCBs shredding, which makes the metals concentrate in the coarser fraction. And the impact force of hammer mill is superior to metal liberation from non metallic components, a satisfied metal liberation degree can be achieved in the wasted PCBs shredding by hammer mill.展开更多
Few studies have been carried out on special shredding technology and equipment,hence it is hard to find out the characteristic rule of distribution of residual films after shredding.By evaluating the mechanical prope...Few studies have been carried out on special shredding technology and equipment,hence it is hard to find out the characteristic rule of distribution of residual films after shredding.By evaluating the mechanical properties of the residual film during the cutting process of a mixture of mechanically recovered residual film and impurities,the main parameters influencing the film distribution feature were acquired.Physical tests were conducted on the basis of a multi-blade toothed shredding device.A relationship model between the film distribution feature and main parameters was constructed through the central grouping method and regression analysis of variance,aiming to investigate the influence rule of main parameters on the film distribution feature and the interaction between them,and to obtain the optimal combination of parameters for the cutting device.The difference between the experimental validation value and the model prediction ranged from 1.03%to 9.56%,which showed that the model has reliable and accurate predictive ability.展开更多
文摘The presence of waste tires poses an environmental challenge as they occupy a significant amount of land and are expensive to dispose in landfills.However,reusing waste tires can address this issue when waste tires are used in geotechnical applications.To determine the viability of this approach,laboratoryscale tests were conducted to investigate load-bearing capacity of circular footings on sand-tire shred(STS)mixtures with shredded waste tire contents of 5%e15%by weight and three different widths of shreds.The investigation focused on analyzing the thickness of layers composed of STS mixtures,the soil cap,and the impact of geogrids on bearing capacity.The results indicate that a specific mixture of sand and tire shreds provides the highest footing-bearing capacity.In addition,the optimal shred content and size were found to be 10%by weight and 2 cm×10 cm,respectively.Furthermore,for a given tire shred width,a particular length provides the largest bearing capacity.The results agree well with that of previous research conducted by the first author and his colleagues in direct shear and California bearing ratio(CBR)tests.The primary finding of this research is that the use of two-layered STS mixtures reinforced by geogrids significantly enhances the bearing capacity.
基金funding by Bhabha Atomic Research Centre (BARC),Mumbai
文摘The performance of a well-designed layer of sand, and composites like layer of sand mixed with shredded rubber tire (RSM) as low cost base isolators, is studied in shake table tests in the laboratory. The building foundation is modeled by a 200 mm by 200 mm and 40 mm thick rigid plexi-glass block. The block is placed in the middle of a 1m by 1m tank filled with sand. The selected base isolator is placed between the block and the sand foundation. Accelerometers are placed on top of the footing and foundation sand layer. The displacement of the footing is also measured by LVDT. The whole setup is mounted on a shake table and subjected to sinusoidal motions with varying amplitude and frequency. Sand is found to be effective only at very high amplitude (> 0.65 g) of motions. The performance of a composite consisting of sand and 50% shredded rubber tire placed under the footing is found to be most promising as a low-cost effective base isolator.
基金support from the National Natural Science Foundations of China(No.52171282,41831280)Shandong Provincial Key Research and Development Plan,China(No.2021ZLGX04)supported by Taishan Scholars of Shandong Province,China(No.tsqn202306098).
文摘Microbial-induced carbonate precipitation(MICP)technique has been adopted in geotechnical engineering widely.In this study,the effect of drying-wetting cycles on MICP-recycled shredded coconut coir(RSC)reinforced calcareous sand was studied,and the deterioration mechanism under drying-wetting cycles was revealed.Test results indicated that drying-wetting cycles exert an important influence on the durability of MICP-RSC reinforced specimens.With the increase of drying-wetting cycles N,the specimens demonstrated significant increase in mass loss rate and critical void ratio,decrease in maximum shear modulus,peak strength and toughness.Furthermore,an increase in the initial relative density reduced the deterioration of MICP-RSC reinforced specimens exposed to drying-wetting cycles.Higher initial relative density of the specimen correlates with an increased maximum shear modulus,peak stress and toughness,a decreased in permeability and critical void ratio.Microanalysis revealed that the generated calcium carbonate adhering to sand particles and RSC gradually dropped off with the increase of N,weakened cementation,and led to the deterioration of MICP-RSC reinforced specimens,which is consistent with the deterioration characteristics under drying-wetting cycles.
文摘Electronic scrap, especially wasted printed circuit boards (PCBs), is regarded as an environmental challenge. At present, the physical separation is thought to be the environmental friendly and economical method of treating and reutilizing electronic waste. An effective liberation of metals from non metallic components is a crucial step towards mechanical separation and recycling of wasted PCBs. In this paper, the selective shredding theory and mechanics characteristics of wasted PCBs were analyzed, and the shredded experiments of wasted PCBs by hammer mill were investigated. The result shows that the selective shredding exists in the wasted PCBs shredded process by hammer mill. The shredding velocity of non metallic components is far greater than that of metals in the wasted PCBs shredding, which makes the metals concentrate in the coarser fraction. And the impact force of hammer mill is superior to metal liberation from non metallic components, a satisfied metal liberation degree can be achieved in the wasted PCBs shredding by hammer mill.
基金National Natural Science Foundation of China(Grant No.52475243)the National Natural Science Foundation of Shandong(Grant No.ZR2023ME209)+2 种基金Scientific Research Fund Project of Dezhou University(Grant No.2023xjrc205)Science and Technology Plan Project of Tiemenguan(Grant No.2023GG2202)Xinjiang Production and Construction Corps Science and Technology Plan Project(Grant No.2024YD014).
文摘Few studies have been carried out on special shredding technology and equipment,hence it is hard to find out the characteristic rule of distribution of residual films after shredding.By evaluating the mechanical properties of the residual film during the cutting process of a mixture of mechanically recovered residual film and impurities,the main parameters influencing the film distribution feature were acquired.Physical tests were conducted on the basis of a multi-blade toothed shredding device.A relationship model between the film distribution feature and main parameters was constructed through the central grouping method and regression analysis of variance,aiming to investigate the influence rule of main parameters on the film distribution feature and the interaction between them,and to obtain the optimal combination of parameters for the cutting device.The difference between the experimental validation value and the model prediction ranged from 1.03%to 9.56%,which showed that the model has reliable and accurate predictive ability.
