Two-course sidewalks shall be constructed as follows: A subgrade shall be prepared by cutting down or filling up the surface of the ground to an elevation which, after being thoroughly compacted, shall be five inches (5") below the sidewalk grade. Wherever filling is necessary, it shall be done with earth or other material equally as good for filling purposes, free from animal or vegetable matter, thoroughly compacted, and placed in layers not more than twelve inches (12") in thickness.
Upon the subgrade shall be placed a layer of Portland cement concrete four and one-fourth inches (41/4") in thickness. The concrete shall consist of one part Portland cement, two and one- half (21/2) parts torpedo sand and four (4) parts crushed stone or gravel, measuring not less than one-fourth inch (1/4") nor more than one and one-half inches (11/2") in any dimension, all of which shall be free from dust, loam and dirt or other foreign substances. The materials shall be thoroughly mixed with water in a batch mixer, or mixed by hand, in which event the cement and sand shall be thoroughly mixed dry, into which shall be incorporated the four (4) parts of stone as specified herein, after which the mixture shall be moistened with water and the whole mass thoroughly mixed and placed on the foundation and rammed until solid. Before the layer last described has set, a finishing layer of Portland cement concrete three-fourths inch (3/4") in thickness shall be placed thereon. The layer shall consist of two (2) parts Portland cement and three (3) parts torpedo sand, thoroughly mixed dry, then moistened with water and mixed again to form a mortar which shall be spread in such a manner as to ensure a smooth and even surface after being thoroughly troweled. (Ord. 27, 1928)