Stable groundwork for 30 million air passengers

London Heathrow Airport was planning the construction of a new Terminal 5 that would allow the huge number of 30 million additional air passengers to check in each year. Before work on the new building could begin, however, extensive earthmoving and stabilizing operations needed to be carried out over an area totalling 750,000 m² to prevent the new terminal and its concrete foundations from sinking into the ground.

The client’s main stipulation was that the binding agents used in the stabilizing process – lime and cement – must be added to the operation without generating any dust. Depending on weather conditions, heavy dust clouds may develop when spreading powdered stabilizing agents ahead of the recycler, which would have been too great a hazard for aircraft taking off or landing.

Wirtgen’s combination machines for cold recycling and soil stabilization, the WR 2500 SK and its predecessor WR 2500 K, were the ideal candidates for the job. Their integrated material silo and proportioning hopper are located inside the machine – a feature permitting them to work in rain or even storm without leaving clouds of dust in their wake.

Tremendous masses of soil would have had to be removed, treated and transported back to the job site, had this stipulation not been met. Assigning the job to the Wirtgen soil stabilizers dispensed with the need for time-consuming, expensive transport, enabling the machines to lay the optimum foundation for the heavy concrete surface that was to be paved in the next step.