Effect of Curing on Roughness Development of Concrete Pavements

Abstract

This paper deals with the results of a study on the effect of curing on as-constructed smoothness and subsequent roughness development of portland cement concrete pavements (PCCP) in Kansas. Ten test sections on five newly built PCCP projects on I-70 and I-135 were selected. At each site, one section was cured with a double application of curing compound as opposed to the single application currently specified. A section of equal length with single application was designated as the control section. Some sections were instrumented with thermocouples to collect temperature data at the bottom of the PCCP slab during construction. Large temperature gradients between the top and the bottom of the PCCP slab were observed during concrete placement. Double curing compound application tends to decrease this temperature gradient. Periodic longitudinal profile data was collected with a South Dakota-type profiler on the wheel paths of both driving and passing lanes on each section. From these profile data international roughness index (IRI) statistics were computed for each test section. Analysis of variance was performed to compare mean IRI values with respect to the curing compound application rate. It was found that the single curing compound results in lower as-constructed IRI values, but double application reduces roughness development in the long run, possibly due to lower differential autogenous volume change of concrete.