(a) Material. Materials must be kept separate and only a recognized grade of Portland cement may be used. Sand shall be clean, sharp lake or bank sand, containing less than five percent of loam, silt or foreign substance. Sand must 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 on a No. 30 sieve. The mineral aggregate may be crushed limestone, slag or graded gravel (the gravel to be all broken or round pebbles with no flats) ranging in size from three- quarters of an inch in the longest dimension to material that will not pass a one-quarter inch screen.
(b) Preparation of Bed. The excavation shall be to a depth of eight inches. The contractor shall remove all excavated material from the premises and no broken concrete shall be used as part of the bed unless it is below the eight inches required for the excavation. A two-inch layer of coarse black cinders shall be tamped into place on the bed. The concrete shall be monolithic (one coat) mix, six inches in thickness, and shall be well tamped into place and have a wood trowel finish.
(c) Manner of Laying. The mixture shall be made of one part cement, two and one- half parts sand and four parts crushed limestone, slag or graded gravel as specified. The mixture must be made in a batch-type mixer, operated one and one-half minutes at the rate of from twelve to eighteen revolutions per minute. Not more than six gallons of water shall be used per sack of cement. The concrete shall be well tamped in place to bring sufficient mortar to the top to cover all stone, using a wood trowel sand finish.
A steel divider not more than one-quarter inch thick shall be used on each side of the driveway where it passes through the sidewalk.
If plant mix is furnished, it shall be mixed on the job, just in advance of pouring in place.
(d) Barricades and Warning Lights. The work must be protected by barricades and red or amber lights must be maintained by the contractor under supervision of the Building Commissioner. All barricades must be maintained for at least four days and during hot, dry weather concrete shall be covered and kept wet for at least two days.
(e) Responsibility of Contractor. In the construction of concrete driveways the contractor shall avoid injury to trees, hedges, fences, flagstones or other construction previously installed and shall employ such safeguards as may be ordered by the City Engineer or the Building Commissioner.
The contractor shall also fill in the tree lawn at each side of the drive with top soil and shall seed the same.
No material will be permitted on streets or sidewalks, nor will any mixing be permitted on a street or sidewalk. No hand mixing will be permitted on any kind of work on City property.
It shall be the duty of the contractor, under the Building Commissioner's directions, when repairing existing drives, to notify all owners that work on their drives will start at a given time. If for any good reason, an owner cannot have the work done on that day, it will be passed until later, but only for a reasonable time.
(Ord. 3260. Passed 6-19-39.)