Foaming characteristics and optimum foaming conditions of waste rubber asphalt
[Purposes]This paper aims to develop a new foamed rubber asphalt by combining rubber asphalt with foaming technology,so as to cover the shortages of the mechanical properties of traditional cold recycled foamed asphalt mixture.[Methods]Two kinds of rubber asphalt with different activation degrees were prepared by the pre-moistening process of waste vegetable oil,with 15.0%rubber powder content.Then,the optimum foaming conditions and technology were determined through the optimization test of foaming characteristics.[Findings]It is feasible to prepare foamed asphalt with activated rubber asphalt.Foaming pressure,foaming temperature,and foaming water consumption have important effects on the foaming effect of rubber asphalt.The expansion rate of rubber asphalt decreases with the increase in foaming pressure,and 300 kPa is recommended as the best foaming pressure.The joint application of waste vegetable oil activation process and foaming agent can achieve the foaming effect of an expansion rate of up to 20.2 times and a half-life period of more than 30 seconds.[Conclusions]This work can effectively solve the problem of poor foaming effect of rubber asphalt and provide a technical reference for the popularization and application of foamed rubber asphalt.