High temperature rheological properties of fiber modified asphalt binders and impact of the type and content on such properties were studied.Three types of fiber,including polyester(PET),polyacrylonitrile(PAN) and cel...High temperature rheological properties of fiber modified asphalt binders and impact of the type and content on such properties were studied.Three types of fiber,including polyester(PET),polyacrylonitrile(PAN) and cellulose(CEL),a control content(0%) and four levels of fiber content(2%,4%,6% and 8% by total asphalt binder mass) were used with asphalt binders.The high temperature rheological properties,consisting of complex modulus(G*) and phase angle δ,were measured using SHRP's dynamic shear rheometer(DSR) between 46-82 ℃.Experimental results indicate that the changes of G* and tan δ of fiber modified asphalt binders with the increase of test temperature tend to slow down,and the temperature susceptibility is improved obviously compared to that of original asphalt binder.Fiber modification results in the increase of rutting parameter(G*/sin δ) at high temperatures,the decrease of temperature susceptibility,and further improved high temperature performance of asphalt binder.An excellent correlation exhibits between fiber content and high temperature performance of asphalt binder.Moreover,fiber type also has different influences on the improvement of G*/sin δ,G*/sin δ of PET and PAN fiber asphalt binders are both higher than that of CEL fiber,but G*/sin δ of CEL fiber is still higher than that of original asphalt.However,there is a critical fiber content when fibers start to interact with each other.Therefore,based on the critical fiber content and economic consideration,the optimum fiber contents for various fiber-modified asphalt binders are obtained.展开更多
In order to improve the quality of Hunyuan inferior Ca-based bentonite （Ca-Bent）, semidry process was used to modify Ca-Bent into superior Na-based bentonite （Na-Bent）. The factors affecting sodium-modification we...In order to improve the quality of Hunyuan inferior Ca-based bentonite （Ca-Bent）, semidry process was used to modify Ca-Bent into superior Na-based bentonite （Na-Bent）. The factors affecting sodium-modification were investigated. The optimized experimental parameters are obtained as follows： Na2CO3 dosage 4.0%, ageing time 25 d, briquetting pressure 25 MPa and briquetting moisture 20%. Under the optimization conditions, the modified Na-Bent has a colloid value of 73.6 mL/（3g）, dilation of 38 mL/g and water absorption in 2 h （2HWA） of 465%, respectively. The bailing results indicate that the modified Na-Bent pellets have higher drop strength and compression strength than the Ca-Bent pellets.展开更多
This study was conducted to assess the performance of modified asphalt binders and engineering properties of mixtures prepared with incorporation 3 vol%and 6 vol%of calcium carbonate(CaCO3),linear low-density polyethy...This study was conducted to assess the performance of modified asphalt binders and engineering properties of mixtures prepared with incorporation 3 vol%and 6 vol%of calcium carbonate(CaCO3),linear low-density polyethylene(LLDPE),and combinations of CaCO3 and LLDPE.The rheological properties of control and modified asphalt binders were evaluated using a series of testing such as rotational viscometer(RV),multiple stress creep recovery(MSCR)and bending beam rheometer(BBR)tests.Meanwhile,four-point beam fatigue test,the dynamic modulus(E*)test and tensile strength ratio(TSR)test were conducted to assess the engineering properties of asphalt mixtures.Based on the findings,the RV and MSCR test result shows that all modified asphalt binders have improved performance in comparison to the neat asphalt binders in terms of higher viscosity and improved permanent deformation resistance.A higher amount of CaCO3 and LLDPE have led modified asphalt binders to better recovery percentage,except the asphalt binders modified using a combination of CaCO3 and LLDPE.However,the inclusion of LLDPE into asphalt binder has lowered the thermal cracking resistance.The incorporation of CaCO3 in asphalt mixtures was found beneficial,especially in improving the ability to resist fatigue cracking of asphalt mixture.In contrast,asphalt mixtures show better moisture sensitivity through the addition of LLDPE.The addition of LLDPE has significantly enhanced the indirect tensile strength values and tensile strength ratio of asphalt mixtures.展开更多
基金Project(2004243) supported by the Science and Technology Key Project of Hubei Province,China
文摘High temperature rheological properties of fiber modified asphalt binders and impact of the type and content on such properties were studied.Three types of fiber,including polyester(PET),polyacrylonitrile(PAN) and cellulose(CEL),a control content(0%) and four levels of fiber content(2%,4%,6% and 8% by total asphalt binder mass) were used with asphalt binders.The high temperature rheological properties,consisting of complex modulus(G*) and phase angle δ,were measured using SHRP's dynamic shear rheometer(DSR) between 46-82 ℃.Experimental results indicate that the changes of G* and tan δ of fiber modified asphalt binders with the increase of test temperature tend to slow down,and the temperature susceptibility is improved obviously compared to that of original asphalt binder.Fiber modification results in the increase of rutting parameter(G*/sin δ) at high temperatures,the decrease of temperature susceptibility,and further improved high temperature performance of asphalt binder.An excellent correlation exhibits between fiber content and high temperature performance of asphalt binder.Moreover,fiber type also has different influences on the improvement of G*/sin δ,G*/sin δ of PET and PAN fiber asphalt binders are both higher than that of CEL fiber,but G*/sin δ of CEL fiber is still higher than that of original asphalt.However,there is a critical fiber content when fibers start to interact with each other.Therefore,based on the critical fiber content and economic consideration,the optimum fiber contents for various fiber-modified asphalt binders are obtained.
基金Project(50725416) supported by the National Science Fund for Distinguished Young Scholars Project(50804059) supported by the National Natural Science Foundation of China+1 种基金 Project(2008BAB32B06) supported by the Key Project in the National Science and Technology Pillar Program during the 11th Five-Year Plan PeriodProject(200805331080) supported by the Specialized Research Fund for the Doctoral Program of Higher Education
文摘In order to improve the quality of Hunyuan inferior Ca-based bentonite （Ca-Bent）, semidry process was used to modify Ca-Bent into superior Na-based bentonite （Na-Bent）. The factors affecting sodium-modification were investigated. The optimized experimental parameters are obtained as follows： Na2CO3 dosage 4.0%, ageing time 25 d, briquetting pressure 25 MPa and briquetting moisture 20%. Under the optimization conditions, the modified Na-Bent has a colloid value of 73.6 mL/（3g）, dilation of 38 mL/g and water absorption in 2 h （2HWA） of 465%, respectively. The bailing results indicate that the modified Na-Bent pellets have higher drop strength and compression strength than the Ca-Bent pellets.
基金The authors grateful to express their appreciation to Specialty Minerals Inc.(Bethlehem,PA,USA),Payne&Dolan Inc.(Waukesha,WI,USA),and Dow Chemical Company(Midland,MI,USA)for donating test materials.The authors would like to acknowledge the research assistantships to Mohd Rosli Mohd Hasan,Mohd Khairul Idham Mohd Satar,Muhammad Naqiuddin Mohd Warid,and Nurul Hidayah Mohd Kamaruddin.The authors also want to acknowledge Julia A.King from the Department of Chemical Engineering of Michigan Technological University for her significant contributions in materials preparation,test design,and paper revision.It is impossible for the authors to complete the work without her effort.Any opinions,findings and conclusions expressed in this paper are those of the authors’and do not necessarily reflect the views of the official views and policies of any institution or company.
文摘This study was conducted to assess the performance of modified asphalt binders and engineering properties of mixtures prepared with incorporation 3 vol%and 6 vol%of calcium carbonate(CaCO3),linear low-density polyethylene(LLDPE),and combinations of CaCO3 and LLDPE.The rheological properties of control and modified asphalt binders were evaluated using a series of testing such as rotational viscometer(RV),multiple stress creep recovery(MSCR)and bending beam rheometer(BBR)tests.Meanwhile,four-point beam fatigue test,the dynamic modulus(E*)test and tensile strength ratio(TSR)test were conducted to assess the engineering properties of asphalt mixtures.Based on the findings,the RV and MSCR test result shows that all modified asphalt binders have improved performance in comparison to the neat asphalt binders in terms of higher viscosity and improved permanent deformation resistance.A higher amount of CaCO3 and LLDPE have led modified asphalt binders to better recovery percentage,except the asphalt binders modified using a combination of CaCO3 and LLDPE.However,the inclusion of LLDPE into asphalt binder has lowered the thermal cracking resistance.The incorporation of CaCO3 in asphalt mixtures was found beneficial,especially in improving the ability to resist fatigue cracking of asphalt mixture.In contrast,asphalt mixtures show better moisture sensitivity through the addition of LLDPE.The addition of LLDPE has significantly enhanced the indirect tensile strength values and tensile strength ratio of asphalt mixtures.
