In this paper, properties of new kind of modified bitumen are presented. Bituminous binder was modified with mix modification using polymer and additive of crumb rubber. Terminal blend process at the refinery was appl...In this paper, properties of new kind of modified bitumen are presented. Bituminous binder was modified with mix modification using polymer and additive of crumb rubber. Terminal blend process at the refinery was applied to produce the mixed modified binder. Laboratory tests were focused on the characterization of the properties of 45/80-55 CR binder with comparison to reference 50/70 and conventional polymer modified 45/80-55 bitumen. Based on conventional binder tests such as penetration, softening point and Fraass breaking point as well as BBR （bending beam rheometer） and DSR （dynamic shear rheometer） tests, rheological properties were investigated. For determination of stability of the polymer and crumb rubber, modified bitumen tube testing method was used. Based on the results analysis, improvement of the viscoelastic properties of polymer and crumb rubber modified bitumen was observed. Conventional properties and stability tests showed that it is possible to pass standard requirements for polymer modified bitumen. Mixed modification and terminal blend allow to use crumb rubber as a modifier with elimination of the separation of crumb rubber during transportation and storage at high temperature. In this paper, experience from filed sections with use of the asphalt mixture with new kind of modified bitumen is presented.展开更多
Based on a variety of case histories of site investigations, including extensive bore hole data, laboratory testing and geophysical prospecting at more than 550 construction sites, an empirical formulation is proposed...Based on a variety of case histories of site investigations, including extensive bore hole data, laboratory testing and geophysical prospecting at more than 550 construction sites, an empirical formulation is proposed for the rapid determination of allowable bearing pressure of shallow foundations in soils and rocks. The proposed expression corroborates consistently with the results of the classical theory and is proven to be rapid, and reliable. Plate load tests have been also carried out at three different sites, in order to further confirm the validity of the proposed method. It consists of only two soil parameters, namely, the in situ measured shear wave velocity and the unit weight. The unit weight may be also determined with sufficient accuracy, by means of other empirical expressions proposed, using P or S -- wave velocities. It is indicated that once the shear and P-wave velocities are measured in situ by an appropriate geophysical survey, the allowable bearing pressure as well as the coefficient of subgrade reaction and many other elasticity parameters may be determined rapidly and reliably.展开更多
文摘In this paper, properties of new kind of modified bitumen are presented. Bituminous binder was modified with mix modification using polymer and additive of crumb rubber. Terminal blend process at the refinery was applied to produce the mixed modified binder. Laboratory tests were focused on the characterization of the properties of 45/80-55 CR binder with comparison to reference 50/70 and conventional polymer modified 45/80-55 bitumen. Based on conventional binder tests such as penetration, softening point and Fraass breaking point as well as BBR （bending beam rheometer） and DSR （dynamic shear rheometer） tests, rheological properties were investigated. For determination of stability of the polymer and crumb rubber, modified bitumen tube testing method was used. Based on the results analysis, improvement of the viscoelastic properties of polymer and crumb rubber modified bitumen was observed. Conventional properties and stability tests showed that it is possible to pass standard requirements for polymer modified bitumen. Mixed modification and terminal blend allow to use crumb rubber as a modifier with elimination of the separation of crumb rubber during transportation and storage at high temperature. In this paper, experience from filed sections with use of the asphalt mixture with new kind of modified bitumen is presented.
文摘Based on a variety of case histories of site investigations, including extensive bore hole data, laboratory testing and geophysical prospecting at more than 550 construction sites, an empirical formulation is proposed for the rapid determination of allowable bearing pressure of shallow foundations in soils and rocks. The proposed expression corroborates consistently with the results of the classical theory and is proven to be rapid, and reliable. Plate load tests have been also carried out at three different sites, in order to further confirm the validity of the proposed method. It consists of only two soil parameters, namely, the in situ measured shear wave velocity and the unit weight. The unit weight may be also determined with sufficient accuracy, by means of other empirical expressions proposed, using P or S -- wave velocities. It is indicated that once the shear and P-wave velocities are measured in situ by an appropriate geophysical survey, the allowable bearing pressure as well as the coefficient of subgrade reaction and many other elasticity parameters may be determined rapidly and reliably.
