Presented in this paper Is a methodology for nondestructive pavement testing and its application in the rehabilitation program of the Talara and Piura Airports, located in the Pacific region of Peru approximately 1000 to 1100 km north of Lima. The area's water table Is 2 to 8 m under the subgrade surface and the annual rainfall ls less than 150 mm. Each airport has a 2500-m runway and Is used mainly by medium-sized and small jet aircraft such as B-727s, B-737s, and F-28s. The existing pavement materials do not meet standard specifications for plasticity, gradation, and California bearing ratio, and the thickness is less than that recommended by the Federal Aviation Administration. Nevertheless, 15 years' experience generally Indicates adequate pavement performance. It was concluded that the most practical way to interpret the actual performance of these marginal materials ls to use nondestructive testing to determine the elastic parameters of the existing subgrade and pavement. The methodology used in Piura and Talara ls based on the Hogg model of a thin plate on an elastic foundation. The subgrade modulus can be determined without prior knowledge of the thickness or the characteristics of the pavement layers. The pavement modulus can then be calculated for any given load and center deftection. The survey indicates that existing pavement materials in such arid zones can generate sufficient bearing capacity to support traffic loads ofB-727s, B-737s, F-28s, and DC-8s. The test results were used to upgrade the existing airport so that they could carry 600 annual operations of B-727s with total gross weights of 160,000 lb for 20 years.

During 1985 and 1986, the Peruvian Air Transportation Authority started the rehabilitation program of Piura and Talara Airports. Both are located in the northern Pacific region of the country about 1000 to 1100 km north of the capital, Lima. These airports are mainly used inter alia as alternatives to the Pan-American Highway connecting the northern Pacific areas with the capital, because some sections of the highway are presently in poor condition. These airports are used mainly by medium-sized and small jet aircraft such as B-727s, B-737s, and F-28s. Occasionally, heavier aircraft, such as DC-8s, use Talara Airport. In both airports, the length of the runway is about 2500 m. Piura Airport is located at coordinates 05 12'S, 8 37'W and its elevation is 35 m above sea level. The airport pavement suffered severe failure in 1982 because of a combination of flooding-very rare in this area-and pavement overstress. The 1982 flash flooding was unusual with a return period of over 100 yr. This pavement failure has limited the effective length of the runway to 1700 m until completion of rehabilitation in November of 1986.