It is the intent of this section to establish minimum quality control requirements for Portland cement concrete construction used in areas other than pavement, in order to assure durable and functional installations that are workmanlike in appearance.
(A) Mix proportions. Portland cement concrete to be used for the construction of structures such as sidewalks, paved ditches, drainageways and medians, and shall conform to the specific mix design criteria as listed Table 153.045 below.
(B) Concrete admixtures.
(1) Concrete admixtures shall conform to Section 1201 - Concrete Admixtures of the IDOT Standard Specifications.
(2) Calcium chloride shall not be added to concrete mixtures except during cold weather construction, and at that time shall not exceed 2%.
TABLE 153.045: PORTLAND CEMENT CONCRETE SPECIFICATIONS
|
TABLE 153.045: PORTLAND CEMENT CONCRETE SPECIFICATIONS
| |
All Non-Pavement Areas IDOT Class of Concrete | SI |
Mix Design: | Type I, Cement |
Minimum Compressive Strength: | 3,500 psi |
Minimum Flexural Strength: | 650 psi |
Coarse Aggregates Permitted: | CA-7 and CA-11 |
Or | CA-14 |
* Slump in inches: | 2 in. to 4 in. |
Air Content: | 5–8% |
Cement Factor (cwt/c.y.): | 6.05 |
* A slump above the maximum specified may be used with the City Engineer’s approval, up to a maximum of 3 inches provided the water/cement ratio does not exceed 0.42 | |
(C) All Portland cement concrete shall be placed in an acceptable and workmanlike manner and at such a consistency that the plastic mixture is workable but does not exceed the slumps stated herein.
(1) No batch/load shall be incorporated that has been in the truck longer than the maximum allowed haul time, as stated in § 153.043(D).
(2) The mixture shall be properly consolidated by vibrator or spading prior to or concurrently with the strike-off operation.
(3) All concrete shall be worked sufficiently to bring one-eighth inch to one-fourth inch of mortar to the surface to allow for proper finishing.
(4) Care shall be exercised to avoid segregation of the mixture.
(D) Subgrade. Under no circumstances shall concrete be placed on a spongy or frozen subgrade.
(E) Forms.
(1) Forms shall be of wood or metal, straight and free from bend or warp, and be clean and securely staked and braced prior to placement of concrete in order to prevent vertical movement during placement and finishing operations.
(2) Forms may deviate from true straightness over a ten-foot length no more than three-eighths inch horizontally or one-fourth inch vertically, as determined with a string line.
(F) Finished texture. Subsequent to initial set, and prior to hardening of the surface, the concrete shall be given a broomed finish at right angles to the centerline of the road, or to the flow line, so that the surface is indented to a nominal depth of one-sixteenth inch.
(G) Curing procedures. Following the application of the finished texture, and as soon as possible without marring the surface, the pavement shall be coated with membrane curing compound as required.
(1) In doing so the contractor shall ensure that adequate and uniform coverage is achieved.
(2) Two separate applications applied at least one minute apart, each at the rate of not less than one gallon per 250 square feet will be required upon the surface.
(3) Type III compound shall be agitated immediately before and during the application.
(4) Membrane curing is not permitted where a protective coat or waterproofing is to be applied, or at any area where rubbing or a normal finish is required, or at construction joints other than those necessary in pavement or base course.
(5) Curing shall be maintained for a minimum of 72 hours.
(H) Cold weather protection. When the National Weather Bureau Forecast for the construction area predicts a temperature of 30°F or lower, or if the actual temperature drops below 32°F or lower, concrete less than 72 hours old shall be protected in the following manner:
(1) If the temperature is predicted to fall or falls to 25°F to 32°F, protection shall consist of two layers of polyethylene sheeting or one layer of polyethylene and one layer of burlap, or two layers of waterproof paper.
(2) If the temperature is predicted to fall or falls below 25°F, protection shall consist of six inches of straw covered with one layer of polyethylene sheeting or waterproof paper.
(Ord. 2009-21, § 18.5-3-21, passed 10-5-2009; Am. Ord. 2016-29, passed 11-7-2016)