Experimental Study on Deflection Response and Load Sensitivity of Cement Pavement Slabs with Edge Displacement at Airports

Under long-term service conditions and heavy aircraft loading, airfield pavements are highly susceptible to slab-bottom voiding, which poses a serious threat to operational safety. This study aims to investigate the deflection response characteristics and load sensitivity of cement concrete slabs with slab edge voiding. Field tests using a Heavy Weight Deflectometer (HWD) were conducted on an apron pavement test section at an airport. The test section consisted of six concrete slabs with dimensions of 4.5 m × 5.0 m, primarily featuring keyed joints with dowel bars. Artificial voids were introduced by embedding EVA foam pads (30 cm × 30 cm × 10 mm) at slab edges, allowing for comparative analysis between voided and intact conditions. Under loading levels of 100 kN and 150 kN, key indicators, including slab edge deflection, slab centre deflection, load transfer efficiency, and edge deflection ratio (with a threshold value of 2.0 specified in civil aviation standards), were measured and analyzed. The results indicate that the load transfer capacity of keyed joints with dowel bars is generally classified as “Fair”. The sensitivity of slab centre deflection to slab edge voiding is less than 2.82%, indicating a negligible influence. No monotonic variation is observed in slab edge deflection or edge deflection ratio between voided and intact conditions. Under certain loading levels, the slab edge deflection of voided slabs is even smaller than that of intact slabs. This abnormal phenomenon is mainly attributed to measurement point positioning errors and the stiffness characteristics of the pavement structure. The findings provide experimental evidence for optimizing the threshold of edge deflection ratio for detecting slab edge voiding in civil aviation airport pavements.