China: Innovative Use of Materials for Highway Construction

Abstract

Ever since the Open Door Policy was set forth, China has been developing rapidly and infrastructure construction has been booming and leaping forward with the economy. The highway network is developing at an unprecedented speed and turns out to be successful and fruitful, reaching almost all cities throughout the country in a decade. The freeway length increases by several thousand kilometers annually. By the end of 2007, the freeways nested inside the entire roadway system of 3.57 million km had reached the length of 53,600 km. The fast development of the highway network improves mobility throughout China, while effectively supporting the economic development in both cities and countryside. Highway development relies heavily on current advanced technologies and applied science, and the innovation and renovation of construction techniques accelerate highway construction in China. In recent years, many important innovations and technical breakthroughs with renovations have occurred in various aspects of highway construction in China. The Global Positioning System GPS , remote sensing RS , and computer-aided design CAD have been integrated for road surveying; in particular, this integrated system is used for scenic design of mountain roads and ramp design of mountain highways. In addition, a single radio station is incorporated into a network-based GPS with a multipleantenna sensing technique. Recently, new techniques have been applied to construct a subgrade/subbase on deserts, freeze-susceptible soils, yellow soils, expansive soils, and soils with substrata rich in calcite and/or dolomite. Mixtures of large-size crushed stones and soils have been used to construct roadway bases. Moreover, new methods are being innovated for stabilizing roadway cut slopes, mitigating embankment settlement and deformation, designing roadway drainage systems, and constructing transition segments connecting highways to bridges. Asphalt paving technologies have been renovated by using modified bituminous binders with polymers, rubber powders, and rubber particles. Also being put into practices are new pavement maintenance strategies, pavement distress survey and assessment using advanced technologies, accelerating bridge deck construction, fire-resistant materials for pavements through tunnels, ultrathin asphalt pavement construction, emulsified asphalt binders for interface coating, and lean concrete treatment to subgrade. These construction technologies incorporated with current environmental protection and safety improvement plans in the road network throughout China will greatly enhance the performance of the entire roadway system.