By ring test and bend test, the improvement of waste tire rubber particles on the crack- resistance and flexural behaviors of cement-based materials were investigated. Test results show that the cracking time of the r...By ring test and bend test, the improvement of waste tire rubber particles on the crack- resistance and flexural behaviors of cement-based materials were investigated. Test results show that the cracking time of the ring specimens can be retarded by the incorporation of rubber particles in the cement paste and mortar. The improvement in the crack-resistance depended on the rubber fraction. When the rubber fraction was 20% in volume, the cracking time was retarded about 15 h for the paste and 24 d for the mortar respectively. Flexural properties were evaluated based on the bend test results for both mortar and concrete containing different amount of rubber particles. Test results show that rubberized mortar and concrete specimens exhibit ductile failure and significant deformation before fracture. The ultimate deformations of both mortar and concrete specimen increase more than 2-4 times than control specimens.展开更多
This paper contains an asymptotic.finite-deformation analysis about theelastostatic field near the,crack-tip in an incompress rubber-like material. The eracktip .field is divided into two narrowing sectors and one exp...This paper contains an asymptotic.finite-deformation analysis about theelastostatic field near the,crack-tip in an incompress rubber-like material. The eracktip .field is divided into two narrowing sectors and one expanding seclor. By the newstyain energy funcion and deformation pattern,we derive and solve the asymptoticequations .for each sector of the tip.field. The singularity of the crack-tip field isdiscussed. The curves of stress-strain of foe crack-tip .field.for an incompress rubber- like material are given and the dominant behaviors of stress and strain near the,cracktip are revealed.展开更多
Global warming awareness criticizes further usage of fossil fuels and insists promotion of renewable energy usage. Additionally, many people in rural areas of developing countries cannot access electricity. To solve t...Global warming awareness criticizes further usage of fossil fuels and insists promotion of renewable energy usage. Additionally, many people in rural areas of developing countries cannot access electricity. To solve this sort of energy crisis including global warming, current authors developed a proto-type of a pyrolysis plant equipped with a prevacuum chamber, which can be used to produce combustible gases for an engine generator in rural areas where people cannot access electricity. The plant is simple and easily maintained in consideration of special conditions that a rural area can receive very few maintenance service, technical assistance, and supply of spare parts. However, gas yield obtained by the proto-type of plant was around 20 wt% of feedstock. One way to enhance gas yield from this proto-type of plant is to utilize reaction of secondary tar cracking. This research work aims to examine possibility of gas yield enhancement keeping a simple structure of the proto-type of plant and using a simple technique of secondary tar cracking. Two tar cracking methods are examined: one is homogeneous tar cracking and the other is heterogeneous tar cracking using catalysis. In the homogeneous tar cracking, pyrolysis gases must be heated up to 650oC to 700oC and in the heterogeneous tar cracking, wood char is used as catalysis, because wood char is byproduct of pyrolysis. It is concluded that the homogeneous tar cracking is quite unlikely in the secondary chamber, but on the other hand, heterogeneous tar cracking using wood char can produce 30 wt% of gas yield from 1 kg of feedstock.展开更多
基金the National Natural Science Foundation of China(No.50679054)
文摘By ring test and bend test, the improvement of waste tire rubber particles on the crack- resistance and flexural behaviors of cement-based materials were investigated. Test results show that the cracking time of the ring specimens can be retarded by the incorporation of rubber particles in the cement paste and mortar. The improvement in the crack-resistance depended on the rubber fraction. When the rubber fraction was 20% in volume, the cracking time was retarded about 15 h for the paste and 24 d for the mortar respectively. Flexural properties were evaluated based on the bend test results for both mortar and concrete containing different amount of rubber particles. Test results show that rubberized mortar and concrete specimens exhibit ductile failure and significant deformation before fracture. The ultimate deformations of both mortar and concrete specimen increase more than 2-4 times than control specimens.
文摘This paper contains an asymptotic.finite-deformation analysis about theelastostatic field near the,crack-tip in an incompress rubber-like material. The eracktip .field is divided into two narrowing sectors and one expanding seclor. By the newstyain energy funcion and deformation pattern,we derive and solve the asymptoticequations .for each sector of the tip.field. The singularity of the crack-tip field isdiscussed. The curves of stress-strain of foe crack-tip .field.for an incompress rubber- like material are given and the dominant behaviors of stress and strain near the,cracktip are revealed.
文摘Global warming awareness criticizes further usage of fossil fuels and insists promotion of renewable energy usage. Additionally, many people in rural areas of developing countries cannot access electricity. To solve this sort of energy crisis including global warming, current authors developed a proto-type of a pyrolysis plant equipped with a prevacuum chamber, which can be used to produce combustible gases for an engine generator in rural areas where people cannot access electricity. The plant is simple and easily maintained in consideration of special conditions that a rural area can receive very few maintenance service, technical assistance, and supply of spare parts. However, gas yield obtained by the proto-type of plant was around 20 wt% of feedstock. One way to enhance gas yield from this proto-type of plant is to utilize reaction of secondary tar cracking. This research work aims to examine possibility of gas yield enhancement keeping a simple structure of the proto-type of plant and using a simple technique of secondary tar cracking. Two tar cracking methods are examined: one is homogeneous tar cracking and the other is heterogeneous tar cracking using catalysis. In the homogeneous tar cracking, pyrolysis gases must be heated up to 650oC to 700oC and in the heterogeneous tar cracking, wood char is used as catalysis, because wood char is byproduct of pyrolysis. It is concluded that the homogeneous tar cracking is quite unlikely in the secondary chamber, but on the other hand, heterogeneous tar cracking using wood char can produce 30 wt% of gas yield from 1 kg of feedstock.
