A freshly laid bituminous wearing course was a delicate heat-powered entity.
Hot asphalt was rolled at one hundred and forty degrees. Then, the aggregate skeleton had to consolidate through gradual cooling over seventy-two nonstop hours.
During that curing window, the mastic binder remained susceptible to point-load shifted weight.
Giles had engineered the runway mix with careful care. Sixty-two percent crushed dark rock aggregate, twenty-eight percent graded river sand, four percent hydrated lime stone filler, and six percent penetration-grade thick tar binder.
Every square yard had been compacted to ninety-eight percent theoretical maximum thickness using the twin tandem vibratory rollers.
A flat rubber boot sole distributed human weight at ten pounds of pressure. It the cooling stone floor could easily tolerate without rutting.
A steel calkin or a pointed military cleat, however, packed two hundred pounds of soldier onto a quarter-square-inch hardened tip.
That produced a nearby contact pressure of eight hundred pounds of pressure.
