GMA material design and construction quality control for asphalt pavement of steel box girder: Case study of the Hong Kong–Zhuhai–Macau Bridge

Abstract

To improve the quality of the Hong Kong–Zhuhai–Macao Bridge paving project, a new paving layer material, Guss-mastic asphalt (GMA), was proposed in this paper by combining the advantages of two types of cast asphalt mixtures: mastic asphalt (MA) and Guss asphalt (GA). Based on the characteristics of GMA, to simulate its actual production process, this study developed a small-simulated cooker mixing equipment. Moreover, the flow degree, 60 ​°C dynamic stability, and impact toughness were proposed to be used to evaluate the construction and ease, high temperature stability, and fatigue resistance of GMA cast asphalt mixtures, respectively. Moreover, the quality control standards for GMA paving materials by indoor tests, field trial mix GMA material performance tests, and accelerated loading tests were finalized. The study showed that the developed simulated cooker yielded consistent mixing results in the same working environment as the engineering cooker device. Increasing the coarse aggregate incorporation rate, coarsening the mastic epure (ME) gradation composition, and using a smaller oil to stone ratio can reduce the flowability of the GMA materials to varying degrees. The four-point bending fatigue life and impact toughness of the different GMA materials are correlated well. A mobility of <20 ​s, 60 ​°C dynamic stability of 400–800 ​times/mm, 15 ​°C impact toughness of ≥400 ​N·mm, and cooker car mixing temperature control standard of 210 ​°C–230 ​°C form an appropriate control index system for the design and production of GMA cast asphalt mixtures. Simultaneously, accelerated loading tests verified the accuracy and reliability of the quality control index system that has been used in the GMA paving project of the Hong Kong–Zhuhai–Macao Bridge deck and has achieved good application results.