Project Description

Diaz·Yourman & Associates (DYA) provided geotechnical services for the rehabilitation of asphalt concrete (AC) pavements along Taxiway B between Taxiway D and Taxiway J at John Wayne Airport (SNA).  The pavement rehabilitation included the adjacent shoulder pavements and the portions of Taxiways D, E, F, G, H, and J located between Taxiway B and the aircraft holding position markings for Runway 2L-20R.

The purpose of DYA's services for the project was to evaluate whether the pavement rehabilitation could be limited to removing and replacing the AC course of the existing pavement section or if full-depth reconstruction of the pavement section was required. DYA performed a field exploration that included the use of testing methods to evaluate the in-situ load supporting capacity and relative compaction of the pavement subgrade soils.  DYA coordinated with SNA Operations to perform the field exploration under temporary closures of the exploration areas to reduce the impact on the site operations.  The primary geotechnical consideration was the presence of two distinct pavement subgrade profiles: dense sandy soils and soft, wet clayey soils.  Accordingly, DYA provided recommendations for portions of the site corresponding to the pavement subgrade soil conditions.  Where the subgrade soils were predominantly sandy, DYA recommended a rehabilitation that was confined only to the existing AC layer of the pavement section.  For areas of clayey subgrade soils, DYA provided recommendations for multiple approaches to improve the subsurface conditions to help support the proposed improvements, including conventional grading, mechanical stabilization (drying and/or using geotextiles), and chemical stabilization (cement).  DYA worked closely with the design team to select the pavement subgrade options that best suited various portions of the project.  In addition, our relationships with pavement contractors was a valuable resource that enabled DYA to provide the design team with insight regarding the equipment types best suited for performing the subgrade preparation and considerations that would help reduce the potential for construction change orders.