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 in Table 34-35 below.
(B) Concrete Admixtures. Concrete admixtures shall conform to Section 1201 - Concrete Admixtures of the IDOT Standard Specifications.
(1) Calcium chloride shall not be added to concrete mixtures except during cold weather construction, and at that time shall not exceed two percent (2%).
TABLE 34-35 PORTLAND CEMENT CONCRETE SPECIFICATIONS |
TABLE 34-35 PORTLAND CEMENT CONCRETE SPECIFICATIONS | |
All Non-Pavement Areas | |
Mix Design: | Type I, Cement |
Minimum Compressive Strength: | 3500 psi |
Minimum Flexural Strength: | 650 psi |
Coarse Aggregates Permitted: | CA-7 & CA-11 |
Or | CA-14 |
* Slump in inches: | 2" to 4" |
Air Content: | 5 - 8% |
Cement Factor (cwt/c.y.): | 6.05 |
(C) All Portland Cement Concrete shall be placed in an acceptable and workmanlike manner and at such a consistency that the plastic mixture workable but does not exceed the slump herein.
(1) No batch/load shall be incorporated that has been in the truck longer than the maximum allowed haul time, as stated in Section 34-3-19(E).
(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 (1/8) inch to one-fourth (1/4) inch of mortar to the surface to for proper finishing.
(4) Care shall be exercised to avoid segregation of the mixture.
(D) Under no circumstances shall concrete be placed on a spongy or frozen sub- grade.
(E) Forms. 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.
(1) Forms may deviate from true straightness over a ten (10) foot length no more than three-eighths (3/8) inch horizontally or one-fourth (1/4) 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 (1/16) 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 insure 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 (1) gallon per two hundred fifty (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 seventy-two (72) hours.
(G) Cold Weather Protection. When the National Weather Bureau Forecast for the construction area predicts a temperature of 32°F or lower, or if the actual temperature drops below 32° F or lower, concrete less than seventy-two (72) hours old shall be protected in the following manner:
(1) If the temperature is predicted to fall, or falls to 25-32°F, protection shall consist of two (2) layers of polyethylene sheeting or one (1) layer of polyethylene and one (1) layer of burlap, or two (2) layers of waterproof paper.
(2) If the temperature is predicted to fall, or falls below 25°F, protection shall consist of six (6) inches of straw covered with one (1) layer of polyethylene sheeting or waterproof paper.