Rehabilitation of Runway 9-27 at Intercontinental Airport of Houston (IAH)

Runway 9–27 was constructed and commissioned into operation in July 1987. Runway 9–27 and its associated taxiways (the south complex) were constructed using an innovative Lime Cement Fly Ash Stabilized Base (LCF Base) with an asphalt surface. This pavement was designed by Dr. Nai Yang. In comparison with concrete pavement alternate, the savings was $10 million for the entire south complex. This south complex is shown in Exhibit No. 1. The compressive strength gain of this LCF Base demonstrated a long, slow rate of pozzolonic reaction with the potential to minimize shrinkage cracking potential and maximize long-term autogeneous healing. From an average of 1200-psi compressive strength in six months, it rose to 2,200 psi in six years and average of 3,000 psi to 3,200-psi compressive strength in ten years. The modulus of elasticity of the LCF Base was approximately 2,000,000 psi in ten years. It was projected during the design phase that rehabilitation would be needed in approximately ten years. The condition of the existing asphalt surface in 1997 at ten years showed widespread reflective cracking. This was due to the shrinkage cracking of the LCF Base. However, the asphalt was deemed to be moderately susceptible to permanent deformation under normal traffic and rut-susceptible under demanding traffic conditions, such as braking and high speed turning. However, potential rutting problems within the existing asphalt are of no practical concern under normal traffic after the application of the recommended overlay. The rehabilitation of Runway 9–27 was performed costing approximately $15 million. Obviously, a task of this magnitude required excellent planning, work at a tumultuous pace, and superb teamwork. In addition, it required a great deal of coordination with the airlines and others.