Comparison of Asphalt Mixtures Designed Using the Marshall and Improved GTM Methods

Abstract

The Marshall method is today considered the standard method of asphalt mixture design for practical engineering applications. By using this method, engineering designers reap the benefits of its easy implementation and inexpensive equipment requirements. However, the Marshall method also has shortcomings and limitations, such as the difficulty in simulating the actual working conditions of a road under heavy load. Therefore, it is desirable to develop alternative methods for designing asphalt mixtures that can simulate the actual conditions under which the road will be used and so enable technically superior road construction. The emergence of the gyratory testing machine (GTM) method represents a new direction in asphalt mixture design that could plan more effectively for heavy loads in a hot and humid environment. In this paper, the two design methods are compared on the basis of the oil-stone ratio, high-temperature stability, water stability, and rutting resistance of the mixes they recommend. We put forward an improved GTM method suitable for the high temperatures and heavy traffic in Guangdong Province. This work provides a foundation for the large-scale popularization and application of the GTM method.