Early-Age Structural Properties of Base Material Treated with Asphalt Emulsion

Abstract

The objectives of this research were to investigate the early-age structural properties of base materials stabilized with asphalt emulsion and to assess the rate at which emulsion-treated base (ETB) design properties are achieved. Three experimental sections were established along a pavement reconstruction project near Saratoga Springs, Utah. Field tests were performed to assess the structural properties of the ETB immediately after construction and at 2, 3, 7, and 14 days; 4 months; and 1 year. Measured values were plotted against time to determine trends in ETB strength development and to determine pavement capacity. Modulus values were consistently low in all three sections during the first 2 weeks after construction, increased dramatically by 4 months, and then decreased considerably by 1 year. In the first 2 weeks after construction, the average ETB structural coefficient was 0.04. Only two of the three sections reached the design structural coefficient of 0.25, which occurred after approximately 3 months; however, the average structural coefficient measured for all three sections after 1 year of curing, which included a winter, was only 47% of the design strength. The results of this research showed that, while pavement capacity was sufficient at 4 months, it was severely reduced during the first 2 weeks and at 1 year. Trafficking under these reduced capacities would be expected to greatly compromise long-term pavement performance. For this reason, trafficking of materials similar to those investigated in this research is not recommended during at least the first 2 weeks after construction.