Performance And Technical Indexes Of Modified Asphalt For Pavement In Moist Heat Areas

In moist heat areas, asphalt pavement is effected by the challenges of high temperature, overloading, rainfall as well as many other adverse external conditions. The use of high-performance modified asphalt is one of the important measures to ensure the performance of the pavement. How to do well in choosing modified asphalt by doing adjust measures to local conditions, as well as accurately controlling the key technical indexes of all kinds of modified asphalts, is the key technology for the application of modified asphalt.In view of the above, this paper chooses a variety of typical high viscous asphalt, rubber powder modified asphalt and two types of new blending modified asphalt, and carried out various kinds of indoor experiments of the modified asphalt about its technology characteristics, and range distributions of technical indexes, and then combined with the technical features of the road project in moist heat areas, this paper deeply analyses the key technical properties of all kinds of modified asphalts, puts forward controlling indexes and standards. The specific research results and conclusions are as follows:By the performance survey about 11 kinds of high viscosity modified asphalts (five kinds of products, six kinds of homemade), the results show that the overall level of high viscosity modified asphalt indexes is higher, but penetration is easy to appear small and 60℃ dynamic viscosity is not stable.Temperature sweep found that product high viscosity modified asphalt majorly improves rutting resistance at higher temperature (about 60℃ or more), but lower rutting resistance below 60℃, even less than asphalt; frequency sweep found that high viscosity modified asphalt has better rutting resistance, the higher the frequency, the stronger the rutting resistance.Using gray relative degree method to study the correlation between conventional indexes (softening point, equivalent softening point,60℃ dynamic viscosity,135℃ viscosity,170℃ viscosity) and rutting factor, the results show that 60℃ dynamic viscosity and rutting factor have good correlation.Experimental study showed that the rubber powder is beneficial to improve asphalt high and low temperature performance, anti-aging properties, elastic recovery performance and ability to resist rutting, the optimal mesh is not same for different asphalt properties, compound modification mainly improved 5℃ ductility,25℃ toughness and tenacity as well as 60℃ dynamic viscosity. Sulfur is unfavorable for rutting resistance of the powder rubber and SBS compound modified asphaltThe study found that adding diatomite or lake asphalt, overall improve the high temperature performance and anti-aging performance of asphalt. But diatomite has lowering effect for rutting factor under different frequency; adding lake asphalt is unfavorable for ductility. Spreading diatomite directly in adhesive layer is extremely unfavorable for resistance to shear and tensile properties.Based on the above studies show that the single index often does not reflect the overall performance of the modified asphalt, the overall scan testing is often essential. Asphalt modification for the effect of various indicators is often not balanced, and even reverse, requires a combination of specific needs, select a specific modification methods and materials. Based on the test results and related analysis, and finally recommended the technical indexes and standards of different modified asphalts in moist heat areas.