Using of rubber asphalt can both promote the recycling of waste tires and improve the performance of asphalt pavement.However,the segregation of rubber asphalt caused by the poor storage stability always appears durin...Using of rubber asphalt can both promote the recycling of waste tires and improve the performance of asphalt pavement.However,the segregation of rubber asphalt caused by the poor storage stability always appears during its application.Storage stability of asphalt and rubber is related to the compatibility and also influenced by rubber content.In this study,molecular models of different rubbers and chemical fractions of asphalt were built to perform the molecular dynamics simulation.The solubility parameter and binding energy between rubber and asphalt were obtained to evaluate the compatibility between rubber and asphalt as well as the influence of rubber content on compatibility.Results show that all three kinds of rubber are commendably compatible with asphalt,where the compatibility between asphalt and cis-polybutadiene rubber(BR)is the best,followed by styrene-butadiene rubber(SBR),and natural rubber(NR)is the worst.The optimum rubber contents for BR asphalt,SBR asphalt,and NR asphalt were determined as 15%,15%,and 20%,respectively.In addition,the upper limits of rubber contents were found as between 25%and 30%,between 20%and 25%,and between 25%and 30%,respectively.展开更多
Superabsorbent polymers(SAPs)are cross-linked polymers that can absorb and retain large amounts of water.In recent years,a growing interest was seen in applying SAPs in concrete to improve its performance due to its e...Superabsorbent polymers(SAPs)are cross-linked polymers that can absorb and retain large amounts of water.In recent years,a growing interest was seen in applying SAPs in concrete to improve its performance due to its efficiency in mitigating shrinkage.This paper presents findings in a study on effect of SAPs on performance of cement-treated base(CTB),using the experience of internal curing of concrete.CTB specimens with and without SAPs were prepared and tested in the laboratory.Tests conducted include mechanical property testing,dry shrinkage testing,differential thermal analysis,mercury intrusion porosimetry and scanning electron microscope testing.It was found that 7-day and 28-day unconfined compressive strength of CTB specimens with SAPs was higher than regular CTB specimens.28d compressive strength of CTB specimens with SAPs made by Static pressure method was 5.87 MPa,which is 27%higher than that of regular CTB specimens.Drying shrinkage of CTB specimens with SAPs was decreased by 52.5%comparing with regular CTB specimens.Through the microstructure analysis it was found that CTB specimens with SAPs could produce more hydration products,which is also the reason for the strength improvement.展开更多
基金This work was supported by the Department of Science&Technology of Shaanxi Province(Nos.2016ZDIC-24 and 2017KCT-13)China Postdoctoral Science Foundation(Nos.2017M620434)+2 种基金the Special Fund for Basic Scientifie Research of Central College of Chang an University (Nos.310821153502 and 310821173501)Intermational cooperation project of Jiangsu Province(No.BZ 2017011)The authors gratefully acknowledge their financial support.
文摘Using of rubber asphalt can both promote the recycling of waste tires and improve the performance of asphalt pavement.However,the segregation of rubber asphalt caused by the poor storage stability always appears during its application.Storage stability of asphalt and rubber is related to the compatibility and also influenced by rubber content.In this study,molecular models of different rubbers and chemical fractions of asphalt were built to perform the molecular dynamics simulation.The solubility parameter and binding energy between rubber and asphalt were obtained to evaluate the compatibility between rubber and asphalt as well as the influence of rubber content on compatibility.Results show that all three kinds of rubber are commendably compatible with asphalt,where the compatibility between asphalt and cis-polybutadiene rubber(BR)is the best,followed by styrene-butadiene rubber(SBR),and natural rubber(NR)is the worst.The optimum rubber contents for BR asphalt,SBR asphalt,and NR asphalt were determined as 15%,15%,and 20%,respectively.In addition,the upper limits of rubber contents were found as between 25%and 30%,between 20%and 25%,and between 25%and 30%,respectively.
基金funded by the International Cooperation Project of Jiangsu Science and Technology Department[Grant No.BZ2017011].
文摘Superabsorbent polymers(SAPs)are cross-linked polymers that can absorb and retain large amounts of water.In recent years,a growing interest was seen in applying SAPs in concrete to improve its performance due to its efficiency in mitigating shrinkage.This paper presents findings in a study on effect of SAPs on performance of cement-treated base(CTB),using the experience of internal curing of concrete.CTB specimens with and without SAPs were prepared and tested in the laboratory.Tests conducted include mechanical property testing,dry shrinkage testing,differential thermal analysis,mercury intrusion porosimetry and scanning electron microscope testing.It was found that 7-day and 28-day unconfined compressive strength of CTB specimens with SAPs was higher than regular CTB specimens.28d compressive strength of CTB specimens with SAPs made by Static pressure method was 5.87 MPa,which is 27%higher than that of regular CTB specimens.Drying shrinkage of CTB specimens with SAPs was decreased by 52.5%comparing with regular CTB specimens.Through the microstructure analysis it was found that CTB specimens with SAPs could produce more hydration products,which is also the reason for the strength improvement.
