Patent ID: 8269483

Claim:
A method for monitoring a building material, the method comprising the steps of: a. mixing a predetermined amount of taggant particles with a predetermined first volume of a first component of a building material to prepare a first mixture in a first mixing device; b. providing a first sensor for generating a first sense signal representing an amount of taggant particles per unit volume of the first mixture flowing into a second mixing device; c. mixing a predetermined second volume of a second component of the building material with the first mixture to prepare a second mixture in the second mixing device; d. providing a second sensor generating a second sense signal representing an amount of taggant particles per unit volume of the second mixture flowing from the second mixing device; e. providing a processor for calculating a ratio of the volumes of the first and second components in the second mixture in response to the first and second sense signals; f. dispensing the second mixture onto a surface; and g. scanning the second mixture disposed on the surface.