Patent ID: 7010893
Filing Date: 2006-03-14
Classification: E04B,F24D,Y02B

Abstract:
1. A concrete floor, comprising: an upper side and an underside with concrete in between; in said concrete a plurality of first concrete-free spaces each having at least two wall surfaces, said at least two wall surfaces being aligned substantially not parallel and not perpendicular to at least one of said under side and upper side; a plurality of second concrete-free spaces in said concrete communicating with and spacing apart said first concrete-free spaces to form a substantially straight line segment of said first and second concrete-free spaces; a plurality of said segments substantially parallel to each other and with the first concrete-free spaces being substantially aligned across from each other in a direction perpendicular to a direction of said straight line segments; and said first concrete-free spaces having a maximum diameter in cross-section larger than a maximum diameter in cross-section of said second concrete-free spaces.