Patents Assigned to Institut fur Privatwirtschaft Gschwend & Stadler
  • Patent number: 4218260
    Abstract: In a road surface and a process for making same, a top layer of reflex reflective concrete in slab or cylindrical form is made of a mixture of white Portland cement, particulate white quartz filler material, colorless crystal balls and titanium dioxide pigment. The quartz filler is a trigonal trapezohedrical .beta.-quartz powder having a refractive index of 1.55 and a particle size less than the glass ball diameters, the latter being from 0.2 to 0.6 mm. The glass balls constitute from 50 to 70% of the mixture and are arranged within the top layer of concrete in successive layers with those balls closest to the impact surface of the top layer being half exposed to intercept light from car headlamps.
    Type: Grant
    Filed: January 5, 1979
    Date of Patent: August 19, 1980
    Assignee: Institut fur Privatwirtschaft Gschwend & Stadler
    Inventor: Heinrich Metzler