All sidewalks shall be constructed of concrete and shall meet the following minimum specifications:
   (a)   Cement. The cement used in concrete shall be Portland cement of a well known brand and shall be subject to testing by the Director of Public Service in accordance with Standard Methods of Sampling and Testing (Designation C 77-37) of the American Society for Testing Materials. All cement used shall have a specific gravity of not less than 3.1 and a residue by weight of not more than eight percent on a No. 100 sieve or twenty-five percent on a No. 200 sieve. All Portland cement, when tested in neat briquettes, shall have a tensile strength of at least 150 pounds per square inch after one hour set in air and twenty-three hours set in water and at least 450 pounds per square inch after one day set in air and six days set in water.
   (b)   Sand. The sand used for concrete shall be clean sharp lake or bank sand containing less than six percent loam or other foreign substances and shall be entirely free from clay, shale or vegetable matter. It shall be uniformly graded from that which will pass a No. 4 sieve to a No. 100 sieve and at least one-third of the material shall be retained upon a No. 30 sieve.
   (c)   Stone. The mineral aggregate shall be crushed limestone ranging from one inch down to one-quarter inch designated in the State of Ohio Department of Highways Construction and Material Specifications as No. 46 size. The limestone shall have a specific gravity of not less than 2.5, a hardness of not less than 12 and a toughness of not less than 4, all determinations to be made according to requirements of the American Society for Testing Materials. The limestone must be machine-broken and screened into the specified sizes. All fragments must be generally cubical in form, free from an excess of flat, thin fragments and contain no shale, silt, clay or foreign substances.
   (d)   Mix. Concrete sidewalk shall be cast from a mixture of one part Portland cement, two parts sand and three and one-half parts limestone, all materials as specified above and only enough clean water to make the mix plastic and workable. In mixing ingredients the proportions shall be determined by volume. The concrete shall have a slump not greater than three inches nor less than two inches when subjected to the Slump Test for Consistency in accordance with the American Society for Testing Materials (Designation D 138-32).
   (e)   Grading. The excavation of subgrade shall include removal of all earth, loam, shale, rock, roots, briars and undergrowth. All spongy material shall be removed. Fills are to be made with cinders or other material acceptable to the Director of Public Service.
   (f)   Forms. Concrete shall be thoroughly mixed before being deposited in clean steel or wooden forms adequately braced to prevent distortion from the specified dimensions. All forms shall be of a size sufficient to produce a walk of a minimum thickness or depth of four inches.
   (g)   Placing Concrete.
      (1)   The concrete shall be thoroughly tamped and consolidated so that none of the stone appears on the surface. The forms must be kept clean and shall be coated with a suitable oil before filling with concrete.
      (2)   Foundation beds shall be sprinkled immediately prior to depositing the concrete.
      (3)   Concrete when mixed shall be rapidly deposited in the forms and any concrete not in final position within thirty minutes after completion of the mixing shall be discarded. Under no circumstances shall concrete be used that has partially set, and the remixing of such materials is prohibited. The concrete shall be deposited between bulkheads of a uniform thickness and to the full depth and width of the walk, irregular or sloping surfaces shall be avoided. The concrete after being placed shall be throughly compacted and brought to the proper pitch and grade with a templet or straight edge.
      (4)   Immediately prior to the finishing of the surface, the walk shall be cut into slabs not longer than six feet on any one side. The joints shall be cut through the full thickness of the walk and the opening so made shall be filled with clean, dry sand well rammed into place. The joints shall be formed by a cutting tool or other means satisfactory to the Engineer. The markings in the surface of the walk at these joints shall not be more than one-fourth inch deep. All edges shall be rounded with an approved edging tool to a radius of one-fourth inch.
   (h)   Surface Finish. The finishing of the walk shall immediately follow the placing and compacting of the concrete. Unless otherwise ordered by the Director of Public Service, a finish produced by rubbing with wood floats will be required. The surface shall be free from depressions or inequalities. The application of dry cement to hasten drying of the surface is prohibited.
   (i)   Curing and Protecting.  In rainy weather the concrete shall be protected as soon as it is finished. In hot or dry weather the contractor shall keep the concrete wet. Sprinkling shall be begun as soon as the concrete is set sufficiently to prevent pitting and shall be continued at such intervals as the weather conditions may require or the Engineer may direct.
   (j)   Expansion Joints. Prepared strips of bitumen and fiber or mineral aggregate shall be placed in concrete walks at intervals of at least twenty feet, also at ends where the walk abuts curbing or other lateral walks and along the building line where the walk is laid full width from the curb to the building or other structures. Similar joints shall be placed around water meter covers, gas boxes, hydrants, lamp standards or other fixed objects projecting through the walk. All strips shall be one-fourth inch in thickness, except for transverse joints when the temperature is below seventy degrees Fahrenheit, in which event the strips shall be one-half inch in thickness. The top of the strip shall be cut off flush with the top of the concrete.
(Ord. 1956-38. Passed 5-14-56.)