Longitudinal joint quality is critical to the successful performance of hot-mix asphalt pavements. The implementation of longitudinal joint quality specifications is gaining momentum in many states, with density being the most common quality parameter. However, distress at the joint is caused by the ability of air and water to enter the pavement structure, an ability that may be more compatible with a measure of permeability. The objective of this study was to provide guidance for the implementation of joint quality specifications by compiling information that more completely describes the relationships of density, absorption, permeability, and infiltration. On two resurfacing projects, eight joint construction techniques were used, and the ability of each to improve joint quality was assessed. In addition, joint quality was evaluated with regard to proximity to the joint. In general, the joint heater, joint stabilizer, and notched wedge construction methods were the best performers in regard to density and permeability. Traditional rolling methods exhibited lesser quality, indicating that additional measures may be necessary to generate acceptable levels of joint quality. For the most appropriate measure of quality, permeability and infiltration adequately discriminated between varying levels of joint quality, as did nuclear density. Reasonable relationships were developed between density, permeability, infiltration, and absorption. Thus, density measurements can be used for assessing joint quality and simultaneously protecting against excessive levels of permeability.

In 2012, roller-compacted concrete (RCC) pavement was used to rehabilitate a deteriorated section of roadway in the Fayetteville Shale Play Area (FSPA), Arkansas. As the result of recent heavy truck traffic related to natural gas exploration efforts in Arkansas, the FSPA has experienced significant pavement distresses that typical maintenance activities cannot sufficiently address. RCC pavement was selected as a potential solution to repair failing pavements in this area because that pavement could be constructed more quickly than conventional concrete pavements and could provide adequate structure for truck traffic. Two sections of RCC pavement were constructed on a rural, two-lane highway. The first was a 7-in. section placed on a cement reconstructed base course, and the second was an 8-in. section placed as an overlay. The RCC mixture contained a nominal, maximum aggregate size of ¾ in. and was designed to meet a minimum, 28-day compressive strength of 5,000 psi. Although some difficulties were encountered during the construction process, the final product was considered successful. Low initial strengths in Section 1 were believed to be caused by a combination of low temperatures and the presence of fly ash in the mix. Fly ash was removed from the mix design before the construction of Section 2 began, and the strength characteristics were much improved. Diamond grinding was used to ensure surface smoothness; this treatment resulted in an average International Roughness Index value of 69.5. After 6 months, a distress survey was performed in which minimal cracking was found. Minor surface distresses, including popouts and deterioration at construction joints, were noted.

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The ability of different operators to obtain similar results when performing laboratory tests on the same material is vital for producing accurate testing results. By conducting trials in triplicate for each of three different testing methods, a measurement of the bulk specific gravity (Gmb) of compacted hot-mix asphalt concrete (HMAC) cores was obtained. An analysis of the variability between operators was investigated using a total of almost 1,300 test results, using HMAC sampled from six projects in Arkansas. Three methods were used to determine the bulk specific gravity of compacted HMAC samples, including saturated surface dry (SSD) (as per AASHTO T166), height and diameter (as per AASHTO T269), and vacuum sealing (using the Corelok vacuum sealing device). In almost all cases, Gmb values determined using the height and diameter method were statistically different from those determined using the SSD and Corelok methods; further, statistical differences were noted in paired analyses between the SSD and Corelok methods. The Corelok method exhibited a lower degree of variability than the other two methods used, based on the standard deviation of test results obtained by different operators. In direct comparison with the SSD method, the Corelok exhibited a lower variability (standard deviation) in 81 percent of the cases. Overall, the Corelok method appears to offer a viable alternative for determining the bulk specific gravity of compacted HMAC. However, agencies seeking to use the Corelok must consider the effect of an apparent shift in Gmb values obtained on resulting HMAC volumetric and compaction properties.