(A) Specifications.
(1) The concrete to be used for curb and gutter construction shall be mixed as follows:
(a) One part by measurement, of any standard brand portland cement;
(b) Two to two and one-half parts by measurement, of fine aggregate (sand, all passing one-quarter inch sieve); and
(c) Three to three-and-one-half parts by measurement, of coarse aggregate (gravel or crushed stone).
(2) (a) The fine aggregate shall consist of natural sand composed of fine granular material and shall be free from injurious amounts of organic impurities.
(b) The coarse aggregate shall conform in general to the following sieve analysis specifications:
Sieve | Percentage |
Passing one and one-half inch sieve | 100% |
Passing one inch sieve | 60-95% |
Passing one-half inch sieve | 10-30% |
Passing No. 4 sieve | 0-5% |
(1978 Code, § 12.04.040)
(B) Storage of aggregates and cement. All aggregates shall be stored on clean, smooth hard surfaces, and cement kept dry under cover until used.
(1978 Code, § 12.04.050)
(C) Mechanical mixing required; exception.
(1) The concrete shall be mixed in a mechanical mixer of approved type, for a period of not less than one minute. During this period of time, enough water to produce a mixture which is workable and plastic, producing a slump of not less than two inches or more than six inches, shall be introduced into the mixer. Mixing time shall be extended if necessary to obtain thorough mixing and uniform consistency. The entire contents of the mixer shall be discharged before any materials are placed therein for the succeeding batch.
(2) The volume of material mixed per batch shall not exceed the manufacturer’s rated capacity of the drum in cubic feet of mixed concrete. Handmixing will not be permitted, except in case of emergency, and then only after special permission has been granted.
1978 Code, § 12.04.060)
(Ord. 104, passed - -1927; Ord. 224, passed - -1944)