Method and apparatus for forming walkways having detectable warning surfaces

A method for forming a concrete surface having visual and tactile warning means for pedestrian traffic and users of wheeled conveyances, including the steps of:

• a) preparing a concrete mixture suitable for pouring into a concrete receiving form;
• b) pouring the concrete mixture into a concrete receiving form;
• c) floating the surface of the poured concrete;
• d) allowing the poured concrete to stand until assuming a partially set plastic state;
• e) substantially covering the surface of the concrete with a release agent of a color different from the color of the concrete;
• f) providing a stamp member having a generally planar stamp surface and a pattern of indentations formed in the generally planar stamp surface;
• g) applying additional colored release agent onto the stamp member substantially covering the generally planar stamp surface and the indentations formed therein;
• h) positioning the stamp member onto the concrete surface with the release agent on the generally planar stamp surface contacting the release agent on the concrete surface;
• i) applying pressure to the stamp member forcing concrete to flow into and to fill the indentations and to simultaneously cause intimate mixing of the colored release agent with the concrete flowing into the indentations;
• j) removing the stamp member yielding a generally planar concrete surface superficially covered with colored release agent and a pattern of shaped projections extending from the generally planar surface, the projections being in a pattern and of a shape corresponding to the pattern and shape of the indentations in the stamp member and the projections comprising an intimate mixture of concrete and colored release agent;
• k) setting the concrete until hardened;
• and
• l) rinsing the entire concrete surface whereby the superficial colored release agent is removed from the generally planar surface leaving the projections colored with the release agent and contrasting with the generally planar surface from which the release agent has been removed.