Sidewalks constructed in any street, avenue, alley or public ground in the city shall be constructed either of concrete, or other material subject to the approval of the city engineer. All materials shall be as follows:
A. No aggregate, either fine or coarse, shall be used containing frost or lumps of frozen material.
B. Fine aggregate shall consist of natural sand with coarse grains predominating. Fine aggregate, when dry, shall pass a screen having four (4) meshes per lineal inch; not more than twenty five percent (25%) shall pass a sieve having fifty (50) meshes per lineal inch and not more than five percent (5%) shall pass a sieve having one hundred (100) meshes per lineal inch. Fine aggregate shall not contain vegetable or other deleterious matter, nor more than three percent (3%) by weight of clay or loam.
C. Coarse aggregate shall consist of clean, durable crushed rock or pebbles graded in size, free from vegetable or other deleterious matter, and shall contain no soft, flat or elongated particles. The size of the coarse aggregate shall be such as to pass a one and one-half inch (11/2") round opening, and shall range from one and one-half inches (11/2") down, not more than five percent (5%) passing a screen having four (4) meshes per lineal inch.
D. The portland cement used in sidewalk construction shall conform to the standard specifications of the American society for testing materials. (1980 Code § 19-20)