# Behavior of Airport Concrete Pavement Slabs
## 2 Construction and Instrumentation  
The facilities of IIA were expanded with four planned stages of construction. The airport was opened in 2001 after the completion of the first stage of construction that included building the first passenger terminal, three cargo terminals, two runways, one control tower, and other facilities. The second stage included the construction of additional boarding areas for the first passenger terminal,  
Figure 1: Flow chart of the study. and another runway was completed in 2008. The third project that included the construction of the second passenger terminal, passenger plane ramp, cargo plane ramp, and other facilities was completed in 2017. Sensors were installed in the concrete pavement constructed at a third-stage construction site in IIA. The concrete slab was placed in early November 2016 (late autumn) when the ambient temperature was decreasing. The sensors were installed at the passenger plane ramp of the second passenger terminal, as shown in Figure 2a. Lean concrete, asphalt, and concrete slabs were constructed on a subgrade with thicknesses of 150, 50, and 500 mm, respectively. The area of each slab was 6 m \(\times\) 6 m. The slab was the thickest one in South Korea, and the maximum size of the coarse aggregate was 40 mm. The concrete slabs, wherein the sensors were installed, were placed manually using the mixture proportions as presented in Table 1.  
Figure 2b presents the pavement slabs wherein the sensors were installed. The sections were categorized into linear and curved zones according to the shape of the airplane route in each zone. Zone A was used to measure the slab curling caused by an environmental load, and zone B was used to measure the slab behavior caused by the loading of aircraft proceeding in a straight line. Zone C was used to measure the slab behavior caused by the loading of aircraft moving in a curve. The temperature and static strain were measured in Zone A over a two-year period. The dynamic strain was measured in Zone B and Zone C from January 2018, when the aircraft began to pass the zones, and the data were analyzed. The influence of aircraft loading on slab behavior shall be reported in future publications. For Zone A, eight temperature sensors and thirty static strain gauges were installed in slab A-1 and slab A-2, and the data were collected at 10 min intervals. The temperature sensors and static strain gauges were installed at different positions and depths of the pavement slab to examine the variations in temperature and strain that were distributed nonlinearly in the pavement. The static strain gauges were self-temperature compensated strain transducer type and KM-100B model. The temperature sensors were thermistor type and 107-L model. Figure 2: _Cont._  
As shown in Figure 3a, the static strain gauges were installed in two corners, one mid-edge, and the centers of slabs A-1 and A-2 because most curling behavior can be observed in the corners. Figure 3a also shows the labels of the sensors installed in slab A-1. The front letter of the label of the sensor was 'L' when the longitudinal direction of the sensor coincided with the movement direction of the airplane, whereas letter 'T' was used when the directions were perpendicular. The last letter was 'L' when the sensor was installed on the left of the slab, whereas letter 'R' indicated that the sensors were installed on the right of the slab. 'ME' implies that the sensors were installed at the mid-edge of the slab, and 'CE' implies that the sensors were installed at the center.