Houston's Ternary Concrete: A Game-Changer in Airport Runway Design

In 2002, Houston's George Bush Intercontinental Airport underwent a major renovation to extend its runway from 6,038 feet to 10,000 feet and widen it to 150 feet. This was done to accommodate larger aircraft like the Boeing 747, which can weigh up to 875,000 pounds.

The new concrete pavement used in the renovation was made with a ternary blend of materials, consisting of 50% Type I portland cement, 25% Class F fly ash, and 25% blast-furnace slag. This mix allowed for significant strength development at later ages while maintaining low permeability.

The engineers behind the project aimed to develop a concrete mixture that could withstand the heavy loads of large aircraft, resist moisture, and remain structurally sound for years. They successfully achieved this goal, with trial batches reaching 800 psi in flexure at 90 days, exceeding the design target of 650 psi.

A study published in Concrete International in 2003 reported that the compressive strengths of cores sampled after about eight months of service were around 6,730 to 9,790 psi. Electrical testing also indicated low permeability, and microscopic analysis revealed a dense concrete structure with minimal microcracking.