Study on grading envelope of AC-16 asphalt mixture based on rutting resistance performance
In this paper, the coarse aggregate packing density tests are studied on different proportion the various particle sizes over 4.75mm, and the demarcation point between coarse and fine aggregate of AC-16 asphalt mixture is 4.75mm, the optimum grading of coarse aggregate is determined by the minimum voids in mineral aggregate. Freeze-Thaw Split and Rutting are tested on 9 kinds of grading AC-16 asphalt mixture with different size and proportion fine aggregate. The results show that the percent passing 4.75mm sieve has affected significantly on the high-temperature rutting resistance and water stability of the asphalt mixture. Based on laboratory test results and grading application experience, it is proposed that the engineering design grading envelope of AC-16 asphalt mixture adapted to the summer hot climates characteristics, which improved the rutting resistance capability of asphalt pavement in hot areas during summer.
Research on Design Method of Multilevel Dense Built-in Gradation
The design system of multilevel dense built-in gradation(MDBG) consisting of coarse skeleton structure and fine skeleton structure was presented on the stage filling theory and particle interfering theory as design basis and the Bailey method as test criterion.The system included coarse aggregate grading design,fine aggregate grading design,synthetic aggregate grading design and checking design gradation by Bailey method.The percentage passing of(0.075 mm) on Bailey method was as a test index,which perfected the evaluation to critical sieve percentage passing of design gradation.Furthermore,the test criterion was afforded to evaluate the gradation in MDBG-16.
ANALYSIS OF SAUDI ARABIAN MARITIME TRANSPORTATION INDUSTRY
This paper analyses the past, present and future of the maritime transportation industry in the Kingdom of Saudi Arabia. Saudi Arabian seaborne trade and the shipping capacity are analysed for the past 15 years. Relationships between the declining Saudi shipping capacity and other economic measures are identified. Analysis of the Saudi Arabian maritime transportation is performed with respect to the world carrier fleets and models are developed to determine the theoretical shipping capacity required for transportation of the national seaborne cargo. Forecasts of the future shipping capacity requirement for the Kingdom are also presented. This paper illustrates the general approach for analysing a country's maritime industry and thus could help other researchers in that respect.