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Development of an Innovative Uniaxial Compression Test to Evaluate Permanent Deformation of Asphalt Mixtures Xingyu Gu, Ph.D.1; Qiao Dong, Ph.D., A.M.ASCE2; and Qingquan Yuan3 Abstract: An innovative uniaxial compression test, capable of simulating the confinement and temperature condition in actual pavement, was developed in this study to evaluate the deformation of asphalt mixtures. Small-diameter loading head was utilized to create a confinement inside the specimen, which is similar to that in the field. Optimized loading head size was determined to provide the best confining effect. To reproduce the actual pavement temperature distribution in the tested specimen, a finite-element method (FEM) model was first developed to predict temperature at different depths of a pavement. Then, the laboratory temperature control system was calibrated by monitoring the temperature inside a dummy specimen to ensure the temperatures at different depths of the specimen are the same as in the pavement Cylindrical specimens with different composition of mixtures were prepared for the uniaxial test to evaluate the deformation of the typical pavement structure at various temperatures, vehicle speeds, and load levels. The developed test method clearly differentiated different materials and reflected the influence of temperature, load time, and level. Test results showed high temperature increased the permanent stain. When the highest ambient temperature level was higher than 28°C, the test effectively differentiated different types of materials. In addition, low vehicle speed and overload significantly increased rutting potential of pavement. DOI: 10.1061/(ASCE)MT.1943-5533 .0001038. © 2014 American Society of Civil Engineers. Author keywords: Pavement permanent deformation; Asphalt mixture; Pavement temperature; Uniaxial compression test; Confinement stress; Vehicle speed; Overload. elearnica.ir-Development_of_an_Innovative_Uniaxial_Compression_Test_to_Evaluate_Permanen.pdf

Effect of Residual Asphalt Content on Creep Strain of Cement Modified Emulsified Asphalt Mixtures Original Article, C20 Oruc,S., Bostancioglu,M., Yilmaz Journal. Civil Eng. Urban. 3(3):122-127 . 2013 Abstract:Objective of this paper is to determine the rutting performance of residual asphalt content on cement modified emulsified asphalt mixtures at heavy duty highways. For this purpose, emulsified asphalt specimens with dense graded aggregate were prepared according to Marshall method for emulsified asphalt-aggregate cold mixture design. The specimens were prepared in such a way that portland cement was substituted for mineral filler in an increased percent from 0 % to 6 %. In this way, three asphalt emulsion mixtures with different residual asphalt contents of 4.2 %, 5.2 %, and 6.2 % by the mass of dry aggregate were produced. Static load asphalt creep tests were performed on the specimens. Based on the experimental work, it has been reached that dense graded cement modified emulsion mixtures are of great performance in rutting compared to hot mixtures with the same aggregate grading and bitumen content. Results showed that cement acts as a secondary binder in emulsion mixture. Creep and permanent deformation resistance are all improved by portland cement addition but the resistance to creep deformation of emulsion mixture was decreased by the increase of residual asphalt content. Keywords: Asphalt Emulsion, Residual Asphalt Content, Cement, Rutting, Creep And Permanent Deformation منبع: [Hidden Content] دانلود: [Hidden Content],C3-21.pdf JCEU,C3-21.pdf