Ryuji Abe

A STUDY OF WINTER ROAD SURFACE MEASURES AT AIRPORTS IN COLD, SNOWY REGIONS

At airports in cold, snowy regions, winter runway surface conditions that prevent airplanes from landing may occur because of decreased skid friction coefficient due to snow and ice, causing inconvenience to users. To improve the skid resistance of runways, the authors focused on high-performance SMA, which forms a rough pavement surface, and considered its application as a surface mixture for runways through laboratory experiments and test construction. The results demonstrated that the technique was effective in improving the friction coefficient under conditions of slush or black ice on the runway surface. In the laboratory experiment, which evaluated freezing and thawing unique to cold, snowy regions as well as durability and other properties, high-performance stone mastic also displayed a level of performance equaling or surpassing that of dense-grade asphalt concrete 20F. a standard surface mixture. SMAs effectiveness as a measure for winter runway surfaces in cold, snowy regions was confirmed.

STUDY ON STRUCTURAL EVALUATION OF PAVEMENT LAYER MODULI OBTAINED BY BACKCALCULATING FWD DEFLECTION DATA

Back calculation by which pavement layer moduli can be estimated from surface deflections, serves an essential tool for its structural evaluation. However its verification has not been fully conducted. Two methods are available, one is static back calculation which utilizes a set of peak surface deflections and the other dynamic back calculation which employs a set of time series deflection data. FWD tests were conducted at pavement test sites and pavement layer moduli are back calculated by both methods. The result of structural evaluation is verified by comparing the measured strains with computed by utilizing these layer moduli and FWD loadings.

EXAMINATION OF CAUSES OF RUNWAY PAVEMENT FAILURE AND MEASURES AT NEW CHITOSE AIRPORT

Blistering of the runway surface course was found during a runway inspection at New Chitose Airport in June 2001. A more detailed survey revealed that water penetration has reduced the bearing capacity of both the surface course and the binder course below the joint, as well as the asphalt stabilization layer. Because of a working time restriction on the runway, the thick lift method, whereby asphalt is placed in a short time, was applied in combination with a large-grain asphalt mixture that can be placed at lower temperatures than usual. The study reports the causes of pavement failure and the results of measures against such failure.