PURPOSES: A methodology using a 3D-engineering technique was developed for implementation in paving Quality Control (QC) practice in bridge overlay paving. METHODS: The as-built surface of a concrete-box-girder bridge tends to exhibit a certain level of undulation or roughness. This is usually caused by the inevitable limitation that camber prediction and construction cannot be perfectly matched. The undulation itself would not be a severe defect in a bridge structure, but it results in a challenge for achieving overlay pavement qualities such as pavement thickness and smoothness. One advantage of the 3D-engineering technique is that it allowed identification in advance, of conditions that will interfere with construction, thus preventing non-conformance qualities from being re-worked. RESULTS : Utilizing this technique, overlay paving was virtually simulated in advance, and insufficient thickness areas and rough sections were visually identified. Paving quantities were automatically computed. Paving level alternatives were correspondingly established based on analysis of the quantitative and 3D visual outputs. CONCLUSIONS: This study showed that this methodology could be successfully utilized for optimizing paving quantity and quality

In Korea, concrete pavements were first applied to highways in 1981 and as a result of continued increase in length over the past years, 2,592 km of concrete pavement network is currently in service, of which 1,399 km(54%) of concrete pavements is 10 years or older, and 233km(9%) is 20 years or older. The length of concrete pavement sections nationwide has been steadily on the rise every year (EXTRI, 2017). Approximately 54% of current concrete pavement highway network will reach the service life limit in 2025 which means around 660 billion won is needed for future pavement repair project (EXTRI, 2017). Given that concrete pavements beyond design life still have a remaining service life, it is economically advantageous to repair them before reconstruction. Asphalt overlays are a major repair method for older concrete pavements. Depending on the concrete pavement condition, thickness and mixture of asphalt overlays are determined. Service life of asphalt overlays varies by the presence, time and size of cracks in existing concrete pavements and reflecting crack at joints. Temperature change of concrete pavement is among the major reaction parameters of reflecting crack. Reflecting crack develops when asphalt bottom-up cracking by longitudinal shrinkage and expansion due to temperature change of the concrete base layer, top-down cracking by temperature difference between top and bottom of concrete, and shear stress by traffic loading are combined (Baek, 2010). Crack and joint behaviors of concrete pavement vary between the base layer and the concrete surface of composite pavement system, and different conductivity by mixture and thickness of asphalt overlay leads to temperature change of concrete base course. This study measured temperatures of each layer of diverse composite pavements in place on site and analyzed differences in temperature change of concrete base layer depending on mixture and thickness of asphalt overlays. Overlay thickness parameters were 5cm and 10cm, two values most widely used, while mixture parameters were SMA and porous asphalt. Based on temperature change of concrete surface, this study also evaluated the difference of temperature change in concrete base layer with an asphalt overlay on top. Findings from this study are expected to be utilized for studies on mechanism and modeling of reflecting crack in old concrete pavements with asphalt overlays.