Influence analysis of foamed asphalt mixture gradation based on mechanical properties
In order to determine the influence and rules of the gradation of foamed asphalt on the mechanical properties, three typical gradations of foamed asphalt including the continuous gradation AC-20, the discontinuous gradation SMA-20 and the skeleton embedded crowded structure FAC-20 were taken for dry and wet splitting strength test, besides the mechanical properties of asphalt mixture under different gradations were systematically researched. The gradation composition fluctuation of four key sieve pores consisting of 0.075 mm, 0.3 mm, 1.18 mm and 4.75 mm affecting the mechanical properties of the foamed asphalt mixture gradation were systematically researched. The experimental results showed that foamed asphalt mixture was not suited for the stable discontinuous gradation; the Wittgen stable recommended gradation of foamed asphalt had better mechanical properties; the passing rate of sieve pore size bellow 0.075mm was the key factor affecting the gradation properties of the foamed asphalt mixture, and the rate between five percent and twelve point five percent had better mechanical properties foamed asphalt mixture; the smaller sieve pore size was, the influence of the fluctuation of the passing rate on the mechanical properties of gradation was greater; among others
Analysis of Choice for Asphalt Mixture Gradation
AC I and AK gradations often used in expressway bitumenious pavement are analyzed and the problems existed in them are pointed out. Some advices for AC I and Ak gradation designs are given according to SMA and Superpave design methods.
A New Vacuum Pressure Infiltration CFRP Method and Preparation Experimental Study of Composite
In order to prepare a carbon-fiber-reinforced polymer composite (CFRP) with ideal microstructure and properties, a new vacuum pressure infiltration CFRP method is proposed based on an analysis of existing CFRP preparation process methods. Research on composite material preparation systems was carried out by using this new method principle. The system mainly includes a fiber pre-forming module, a vacuum heating infiltration module, a hot-press curing molding module, and a data acquisition control module. Under the conditions of natural curing at 0 MPa + 6 h + 25 °C, vacuum heating curing at –0.05 MPa + 30 min + 80 °C, and hot-press curing at 0.7 MPa + 5 min + 50 °C, a two-dimensional (2D) CFRP with excellent microstructure and properties was successfully prepared. Observing the microstructure of the prepared composite material, it can be found that the inside of the composite material was sufficiently and uniformly infiltrated, and common preparation defects such as holes and delamination were effectively controlled. Through the performance test, the bending strength of the material reached 790 MPa.