In the past decade,the economy of China has been increasing at a remarkable speed,which causes the rapid increase of automobile industry.Researches in past years demonstrated that the incorporation of crumb rubber int...In the past decade,the economy of China has been increasing at a remarkable speed,which causes the rapid increase of automobile industry.Researches in past years demonstrated that the incorporation of crumb rubber into concrete reduces the mechanical strength of concrete.However,properties such as plastic shrinkage cracking resistance,dry shrinkage cracking resistance,frost resistance,impact resistance,fatigue resistance etc.are improved due to the deformable feature of crumb rubber.Therefore,it is expected that using crumb rubber in concrete not only improves the properties of the material,but also reduces the environmental pressure of handling waste tires.展开更多
This paper evaluates the properties and use of recycled rubber tyres in the form of rubber crumb as a freeze/thaw protection agent when used in concrete.Reusing scrap tyres in the form of rubber crumb in concrete coul...This paper evaluates the properties and use of recycled rubber tyres in the form of rubber crumb as a freeze/thaw protection agent when used in concrete.Reusing scrap tyres in the form of rubber crumb in concrete could benefit the environment by contributing to the percentage of tyres used for a variety of recycling processes such as carpet underlay or tyre derived fuel,thus reducing disposal of tyres to landfill sites and the chemical usage of air entraining agents as a means of achieving freeze/thaw protection.Concrete cubes of 100mm were produced from design mixes which have been classified as plain,air entrained and rubber crumb and subjected to freeze/thaw cycles at 5 days of age.Thawing was conducted in water to ensure full saturation of pores and maximum stress on the concrete samples.The rubber crumb and plain concrete mixes were compared against the freeze/thaw performance of that entrained with air.Air entrainment is known to protect against freeze/thaw action.Rubber crumb when used at a 0.5%addition by volume provided the optimum freeze/thaw protection whilst maintaining the maximum compressive strength.The research shows that rubber crumb was effective at providing freeze/thaw protection albeit with a reduced compressive strength when compared to air entrained concrete.The practical constraints of the test program were time and freezer space so the test was limited to 50 freeze/thaw cycles,which was sufficient for conclusions to be drawn.This paper contributes to the understanding of the effects of varying doses of rubber crumb in concrete when used as a freeze/thaw protection additive.The final compressive strength of the concrete mixes tested at freeze/thaw and non freeze/thaw conditions are determined.The compaction of concrete is raised as an area of concern with regard to rubber particle separation within the plastic phase of the concrete’s life.展开更多
Conventional repairing methods for asphalt pavement have some inconveniences,such as insufficient strength,and are typically time-consuming.To address these issues,this study proposes a new technological method to des...Conventional repairing methods for asphalt pavement have some inconveniences,such as insufficient strength,and are typically time-consuming.To address these issues,this study proposes a new technological method to design and prepare a high-performance assembled asphalt concrete block for fast repair of the potholes.A series of composite modified asphalt binders with 10%crumb rubber(CR)and different dosages(0%,1%,3%,5%)of polyurethane(PU)are examined to determine the optimized binder.Subsequently,the corresponding asphalt mixtures are prepared for further comparison and assessment of engineering properties,such as moistureinduced damage,high-temperature deformation,and low-temperature cracking characteristics.The test results show that PU can significantly improve the high-temperature performance and hardness of(crumb rubber modified asphalt)CRMA binder;3%PU contributes allowing the resistance of CRMA mixture to moisture-induced damage at higher levels,particularly under water whole immersion;as 3%PU is added,the high-temperature rutting deformation resistance of the CRMA mixture increases significantly,and the low-temperature anti-cracking properties are also improved slightly.Therefore,the innovatively designed high-quality assembled fast-repairing asphalt concrete block is recommended as an appropriate option for highway maintenance.展开更多
文摘In the past decade,the economy of China has been increasing at a remarkable speed,which causes the rapid increase of automobile industry.Researches in past years demonstrated that the incorporation of crumb rubber into concrete reduces the mechanical strength of concrete.However,properties such as plastic shrinkage cracking resistance,dry shrinkage cracking resistance,frost resistance,impact resistance,fatigue resistance etc.are improved due to the deformable feature of crumb rubber.Therefore,it is expected that using crumb rubber in concrete not only improves the properties of the material,but also reduces the environmental pressure of handling waste tires.
文摘This paper evaluates the properties and use of recycled rubber tyres in the form of rubber crumb as a freeze/thaw protection agent when used in concrete.Reusing scrap tyres in the form of rubber crumb in concrete could benefit the environment by contributing to the percentage of tyres used for a variety of recycling processes such as carpet underlay or tyre derived fuel,thus reducing disposal of tyres to landfill sites and the chemical usage of air entraining agents as a means of achieving freeze/thaw protection.Concrete cubes of 100mm were produced from design mixes which have been classified as plain,air entrained and rubber crumb and subjected to freeze/thaw cycles at 5 days of age.Thawing was conducted in water to ensure full saturation of pores and maximum stress on the concrete samples.The rubber crumb and plain concrete mixes were compared against the freeze/thaw performance of that entrained with air.Air entrainment is known to protect against freeze/thaw action.Rubber crumb when used at a 0.5%addition by volume provided the optimum freeze/thaw protection whilst maintaining the maximum compressive strength.The research shows that rubber crumb was effective at providing freeze/thaw protection albeit with a reduced compressive strength when compared to air entrained concrete.The practical constraints of the test program were time and freezer space so the test was limited to 50 freeze/thaw cycles,which was sufficient for conclusions to be drawn.This paper contributes to the understanding of the effects of varying doses of rubber crumb in concrete when used as a freeze/thaw protection additive.The final compressive strength of the concrete mixes tested at freeze/thaw and non freeze/thaw conditions are determined.The compaction of concrete is raised as an area of concern with regard to rubber particle separation within the plastic phase of the concrete’s life.
基金the Scientific Technology R&D Project of CCCC Asset Management Co.,Ltd.(RP2022015294&RP2022015296).
文摘Conventional repairing methods for asphalt pavement have some inconveniences,such as insufficient strength,and are typically time-consuming.To address these issues,this study proposes a new technological method to design and prepare a high-performance assembled asphalt concrete block for fast repair of the potholes.A series of composite modified asphalt binders with 10%crumb rubber(CR)and different dosages(0%,1%,3%,5%)of polyurethane(PU)are examined to determine the optimized binder.Subsequently,the corresponding asphalt mixtures are prepared for further comparison and assessment of engineering properties,such as moistureinduced damage,high-temperature deformation,and low-temperature cracking characteristics.The test results show that PU can significantly improve the high-temperature performance and hardness of(crumb rubber modified asphalt)CRMA binder;3%PU contributes allowing the resistance of CRMA mixture to moisture-induced damage at higher levels,particularly under water whole immersion;as 3%PU is added,the high-temperature rutting deformation resistance of the CRMA mixture increases significantly,and the low-temperature anti-cracking properties are also improved slightly.Therefore,the innovatively designed high-quality assembled fast-repairing asphalt concrete block is recommended as an appropriate option for highway maintenance.
