BACKGROUND

The use of RCC pavement was pioneered in North America by the US Army Corps of Engineers. In 1975 a test section of 3.7 X 32.0 m (12 X 105 ft) was placed by the Waterways Experiment Station as part of a street in Mississippi (J). However, the first large-scale construction of RCC pavement, a 16,000-m2 (4-acre) log-sorting yard, took place in British Columbia, Canada, in 1976 (2). The pavement slabs, with a thickness of 355 mm (14 in.), were placed in two lifts. Slab thickness design was based essentially on engineering judgment and experience obtained from cement-stabilized base. No joints other than construction joints were provided. Slabs were allowed to crack naturally, and the spacing was generally in the range of 12 to 18 m (40 to 60 ft).· Following the success of the first application, several other logsorting yards in British Columbia were constructed with RCC. All of the pavements had the same thickness, 355 mm (14 in.), as the first pavement, and the same design concept used for the first pavement was used. Usually, the remainder of the structural system consisted of a 150-mm (6-in.) granular subbase placed over a consolidated subgrade. The design method for RCC pavements currently used in Canada is the PCA's airport thickness design procedure. In the United States the first production project of RCC pavement, a test section 71.4 m (234 ft) long by 6.1 m (20 ft) wide, was constructed at Fort Stewart, Georgia, in July 1983 (3, 4). The pavement had a slab thickness ranging from 230 to 330 mm (9 to 13 in.) and currently serves as an access from a tracked-vehicle parking area to a series of tank trials. In July 1984 a 15 OOO-m2 (18,000-yd2) RCC parking area was constructed at Fort Hood, Texas. This 255-mm (10-in.)-thick pavement was designed to carry 54 000-kg (120,000-lb) tracked vehicles as normal traffic. Because of their early success, RCC pavements have been used on several large-scale projects since 1985. These projects include the following: