Roller-Compacted Concrete Shoulder Construction on Interstate Highway in Georgia

Abstract

In 2004, the Georgia Department of Transportation (GDOT) used roller-compacted concrete (RCC) for Interstate 285 shoulder reconstruction in Atlanta. This instance marks the first usage of RCC pavement in the Interstate highway system in the United States. The construction procedures are described, and the mix design data for the RCC material are presented. The results of a comprehensive field and laboratory investigation of the pertinent material properties are also presented. The 6- and 8-in. (150- and 200-mm) RCC shoulder was constructed with minimal disruption for the traveling public and has performed well to date. The RCC mix was designed for a 4,000-psi (27.6-MPa) compressive strength with 0.5-in. (12.5-mm) maximum size aggregate. More than 98% of the maximum wet density, as specified in the GDOT provision for average in-field density, was achieved in tests at random locations. The average compressive strength in the middle section showed close agreement with the design strength. Reasonably good density and strength values were achieved in the longitudinal joint area and right edge area. The strength from the field-manufactured cylinders did not adequately represent the core strength of RCC, but it was recommended to include the cylinder test in the specification to monitor mixture variability and strength development. A small increase in average density resulted in a larger increase in average compressive strength, but no strong linear relationship was established in individual data. The 8-in. RCC section demonstrated a higher average strength than the 6-in. section, but it also showed a greater propensity for shrinkage cracks.