Bubbles on the Appearance of Hangzhou-Ningbo Expressway

Background

The project is an important part of the Hangzhou-Ningbo Expressway Duplication Line, a national expressway. It also serves as a vital transport corridor for the collection and distribution of goods for the Ningbo-Zhoushan Port. With a total length of 26.15 kilometers, it is constructed on a two-way and six-lane expressway with a design speed of 100 kilometers per hour.After the completion of the project, the Liuheng Highway Bridge and the Hangzhou-Ningbo Expressway Duplication Line will be directly connected. Vehicles traveling from Meishan and Liuheng will be able to reach Zhoushan, Shaoxing Coastal Area, and Hangzhou without having to detour through the urban area of Ningbo.

Project challenge

The appearance of the C40 test pier on site is densely covered with bubbles (Figure 1), most of which are defective pores. When the condition is severe, the upper layer is densely packed with small bubbles, and a relatively thick layer of floating slurry appears after vibration. In addition, the project requires that no thick layer of floating slurry shall appear on the surface of the concrete after vibration. After forming, the pier body surface shall be free of dense bubbles and obvious water ripples.

Fig.1 Appearance of field test pier