Current certification aspects are in CS 25.109 where there are vaguely similar equations.
Some of the flight test assumptions are in AMC 25.109 para 3.5. “The tyres and brakes should not be new, but need not be in the fully worn condition. They should be in a condition considered representative of typical in-service operations
Anti-skid efficiency is discussed in para 3, (92% max), and the runway surface in para 3.3, which should be smooth.
Porous runways are discussed in 109 (d) 2
There are references to ESDU 71026 for braking coefficient of friction:
IHS ESDU 71026
IHS ESDU 95015
Also, see www.spaceagecontrol.com/AC25-7A.pdf
references to 25.109