In recent years,the amount of waste generated during milling has increased dramatically,and improper disposal poses a significant environmental challenge.To mitigate environmental pollution and enhance the road perfor...In recent years,the amount of waste generated during milling has increased dramatically,and improper disposal poses a significant environmental challenge.To mitigate environmental pollution and enhance the road performance of emulsified asphalt cold recycled mixtures(ECRM),this study employed recycled asphalt pavement(RAP)and reclaimed inorganic binder stabilized aggregate(RAI)as dual recycled materials for ECRM preparation.The blending ratios of reclaimed base and surface layer mixtures significantly influence ECRM's performance,with adjusted proportions substantially improving compressive strength and dynamic modulus.Firstly,three distinct proportioning options were developed for the recycled materials.Mix designs incorporating varying RAP/RAI ratios were used to determine the optimal mix parameters:moisture content,cement dosage,and emulsified asphalt content.Subsequently,comprehensive performance evaluations were conducted through high-temperature wheel tracking tests,freeze-thaw splitting tests,uniaxial compression tests,and dynamic modulus measurements to analyze the pavement characteristics of the three ECRM formulations.Experimental results demonstrate:Compared with ECRM with a blending ratio of RAP:RAI:new aggregate=30:50:20(Option 1),the dynamic stability,freeze-thaw splitting strength ratio,compressive strength,and compressive resilient modulus of ECRM under Option 3(RAP:RAI:new aggregate=50:30:20)decreased by 31.8%,5.2%,16.4%,and 13.1%,respectively.This indicates that increasing RAP content while reducing RAI proportion enhances the tensile strength of ECRM,yet adversely affects its high-temperature stability,moisture resistance,and compressive performance.This work not only addresses the challenge of jointly utilizing asphalt pavement waste and base waste,but also provides a cost-effective and sustainable method for the stable application of milling material resources in road engineering.展开更多
Waste plastics and rubber have always posed a threat to the environment and a great challenge for disposal.The use of these two waste materials as modifiers for road asphalt provides new road asphalt binders and at th...Waste plastics and rubber have always posed a threat to the environment and a great challenge for disposal.The use of these two waste materials as modifiers for road asphalt provides new road asphalt binders and at the same time provides a new way for waste material resource treatment.Rubber-modified asphalt and plastic-modified asphalt have received widespread attention due to their green and low-carbon characteristics and some performance advantages,but there are still some performance shortcomings that hinder their promotion and application.In order to continue to explore the application of waste materials in the field of road engineering,combined with the performance advantages of both,many scholars began to study the rubber-plastic composite modified asphalt(RPCMA).Therefore,this paper reviewed the different types of waste rubber and plastic,the comprehensive performance of different types of asphalt and its mixture performance,analyzed the modification mechanism of rubber-plastic composite modified asphalt and its performance changes.The results show that rubber-plastic composite modified asphalt is mostly prepared by directly adding modified materials.However,the pretreatment or melt granulation of rubber and plastic will make the performance of rubber-plastic modified asphalt has improved.There is a mutual promotion mechanism between rubber and plastic in asphalt,which makes the performance of rubber-plastic modified asphalt better than that of asphalt obtained by a single modification method(rubber modified asphalt or plastic modified asphalt).In some properties,it can be close to the commercial SBS modified asphalt.The performance of rubber and plastic composite modified asphalt at high temperature has been generally recognized by researchers,but its low-temperature performance is still controversial.Therefore,it is recommended to apply in high-temperature areas.Future work should focus on the development of composite modifiers with stable performance,low cost and ease of use,standardization of modification processes,improvement of low-temperature performance,and monitoring of road performance and environmental impact.展开更多
基金sponsored by National Natural Science Foundation of China(No.52308466)SASAC Science and Technology Innovation Project(JF-23-01-0063)Shaanxi Provincial Transportation Research Project(25-84 K,25-85 K).
文摘In recent years,the amount of waste generated during milling has increased dramatically,and improper disposal poses a significant environmental challenge.To mitigate environmental pollution and enhance the road performance of emulsified asphalt cold recycled mixtures(ECRM),this study employed recycled asphalt pavement(RAP)and reclaimed inorganic binder stabilized aggregate(RAI)as dual recycled materials for ECRM preparation.The blending ratios of reclaimed base and surface layer mixtures significantly influence ECRM's performance,with adjusted proportions substantially improving compressive strength and dynamic modulus.Firstly,three distinct proportioning options were developed for the recycled materials.Mix designs incorporating varying RAP/RAI ratios were used to determine the optimal mix parameters:moisture content,cement dosage,and emulsified asphalt content.Subsequently,comprehensive performance evaluations were conducted through high-temperature wheel tracking tests,freeze-thaw splitting tests,uniaxial compression tests,and dynamic modulus measurements to analyze the pavement characteristics of the three ECRM formulations.Experimental results demonstrate:Compared with ECRM with a blending ratio of RAP:RAI:new aggregate=30:50:20(Option 1),the dynamic stability,freeze-thaw splitting strength ratio,compressive strength,and compressive resilient modulus of ECRM under Option 3(RAP:RAI:new aggregate=50:30:20)decreased by 31.8%,5.2%,16.4%,and 13.1%,respectively.This indicates that increasing RAP content while reducing RAI proportion enhances the tensile strength of ECRM,yet adversely affects its high-temperature stability,moisture resistance,and compressive performance.This work not only addresses the challenge of jointly utilizing asphalt pavement waste and base waste,but also provides a cost-effective and sustainable method for the stable application of milling material resources in road engineering.
基金sponsored by National Natural Science Foundation of China(No.52308466,No.42271144,No.42071100)Key Research and Development Project of Shaanxi Province(2022SF-328,2022GY-427)+1 种基金the SASAC Science and Technology Innovation Project(JF-23-01-0063)Shaanxi Provincial Transportation Research Project(24-19K,24-20K).
文摘Waste plastics and rubber have always posed a threat to the environment and a great challenge for disposal.The use of these two waste materials as modifiers for road asphalt provides new road asphalt binders and at the same time provides a new way for waste material resource treatment.Rubber-modified asphalt and plastic-modified asphalt have received widespread attention due to their green and low-carbon characteristics and some performance advantages,but there are still some performance shortcomings that hinder their promotion and application.In order to continue to explore the application of waste materials in the field of road engineering,combined with the performance advantages of both,many scholars began to study the rubber-plastic composite modified asphalt(RPCMA).Therefore,this paper reviewed the different types of waste rubber and plastic,the comprehensive performance of different types of asphalt and its mixture performance,analyzed the modification mechanism of rubber-plastic composite modified asphalt and its performance changes.The results show that rubber-plastic composite modified asphalt is mostly prepared by directly adding modified materials.However,the pretreatment or melt granulation of rubber and plastic will make the performance of rubber-plastic modified asphalt has improved.There is a mutual promotion mechanism between rubber and plastic in asphalt,which makes the performance of rubber-plastic modified asphalt better than that of asphalt obtained by a single modification method(rubber modified asphalt or plastic modified asphalt).In some properties,it can be close to the commercial SBS modified asphalt.The performance of rubber and plastic composite modified asphalt at high temperature has been generally recognized by researchers,but its low-temperature performance is still controversial.Therefore,it is recommended to apply in high-temperature areas.Future work should focus on the development of composite modifiers with stable performance,low cost and ease of use,standardization of modification processes,improvement of low-temperature performance,and monitoring of road performance and environmental impact.
