It should be emphasized that the settlement contour map is essential in understanding the water blockage problem encountered in the airfield pavement. The amount of settlement is equivalent to the depth of the sand blanket relative to the original ground elevations of +0.0 m MSL. During pavement construction, some areas were backfilled with C1 sand (fine content of less than 10%) or crushed rock to raise the elevation to required level for placement of the cement treated base.