Design And Construction Control Of Asphalt Mixtures In Xiaopotou Section Of Tianjin-Shanwei Expressway

The paper relies on the preject of Xiaopotou section in Tianjin-Shanwei expressway, Xiaopotou section is Longitudinal longer and steep slope, this makes cars moving slower and increased by the road surface and rutting damage. This paper study asphalt mixture design and test comparative based on the situation.In recent years, an increasing number of highway pavement defects survey showed that Expressway long longitudinal sections of the road asphalt pavement of a high incidence of disease. Compared with the general section, the highway long longitudinal sections of road damage to the main feature of the track, owner, etc. more serious permanent deformation, and thus trigger other diseases of the road have. Vehicle Longitudinal sections of the long slow down the speed, but also in the process of climbing tire and the road surface friction increases, caused asphalt mixture structure within the shear stress greatly increased, thus speeding up the asphalt mixture of permanent deformation process. In this paper the characteristics of the traffic load from the asphalt material selection and design optimization graded start. Research asphalt mixture design methodology and design of theasphalt mixture resistance to permanent deformation properties of the analysis and evaluation, and the squeezed-graded asphalt mixture of construction quality control methods.In the asphalt mixture aggregate gradation design optimization of the two methods of study, Superpave gradation that the design method and Bailey Law.Superpave is SHRP research results, is a set of system design, including the following sections: Superpave Binder norms; Superpave mixture volume design; Superpave mixture performance prediction; related software, testing methods and equipment. Superpave mixture volume design includes the following four steps: Material selection; Aggregate structure design choice; Design asphalt content of choice; Water sensitivity evaluation. Superpave design gradation in addition to providing choice restrictions and control points to control the direction of gradation, experience designers need to choose three qualified as group-level grading candidates for the design of evaluation and selection. Multi-Dense-graded allocation rules designed to gradually filling theory and particle theory to interfere in the design, Bailey to France for the design and testing standards, the guarantee of coarse aggregate skeleton structure formed on the basis of attention to fine aggregate skeleton structure of the design, therebyforming a multi-level squeezed dense skeleton structure of the asphalt mixture.Bailey grading method is divided into coarse aggregate, the fine two-part distribution of the design and evaluation, crude, Fine Aggregate division is the largest aggregate nominal size of 0.22 times NMPS corresponding to the similar size sieve (known as the first control sieve) aperture PCS as a criteria for the classification. PCS=NMPS×0.22Right fine aggregate gradation evaluation also divided into two parts. Fine Aggregate of the further division of PCS to 0.22 times as a cutoff point, known as the second control Sieve aperture SCS; Fine Aggregate of further division, SCS to the 0.22 times as a cutoff point, as the third Sieve aperture control TCS.Bailey demanded fine aggregate amount should be based on coarse aggregate form to the gap, and were extended to a more detailed aggregate, PCS is less than the aggregate may not exceed PCS distraction of aggregate formation of skeleton; SCS is less than the aggregate may not exceed SCS distraction Synthesis of aggregate formation of the skeleton; TCS is less than the aggregate may not exceed TCS shake Synthesis aggregate formation of the skeleton.Superpave is a complete mixture design system, Bailey is squeezedgrading design an effective tool, Bailey-class design and distribution of Superpave design combined, can design a good performance of the asphalt mixture.Asphalt Mix designed with the best method of Superpave asphalt content design, through water stability test, test track, Hamburg rutting test for the appointment performance evaluation.Splitting freeze-thaw tests showed : alkaline stone and asphalt viscosity can improve the design mixture easier standard indicators, SMA mixture of anti-edge water damage than continuous gradation mixture better.Rutting used test and test again Hamburg round of the combination, comprehensive evaluation of asphalt mixture stability of the high-temperature stability and water. Rutting Hamburg round of tests and test results show again the asphalt binder and aggregate level matching mixture rutting ability to play the role. Aggregate size distribution and the quality of the squeezed degree of confrontation rutting ability higher than the contribution of Asphalt Binder viscosity confrontation rutting more contributions Obviously, the asphalt mixture should be designed to aggregate the choice of a reasonable distribution in the design, instead of blindly use of low-grade asphalt or modified asphalt.According to laboratory and field test results of raw materials, compared with a goal and production test.The trial section is constructed in right of Xiaopotou section K56+000～K56+200(total length is 200m)in September,2006.During the construction process and strictly control the quality of the project.