(A) Base.
(1) Material shall be granular, consisting essentially of sand, gravel, rock slag, disintegrated granite or a combination of such materials. It shall be a well graded mixture containing sufficient soil mortar, crusher dust or other binding material which, when placed and compacted, will result in a firm, stable foundation. Material composed of uniformly sized particles or which contains pockets of excessively fine or excessively coarse material will not be acceptable. The material shall meet the following gradation:
Sieve Designation | Percent By Weight Passing |
2.5 inch | 100 |
2 inch | 95—100 |
No. 40 | 30—60 |
No. 200 | 5—15 |
(2) All material passing the No. 40 sieve shall have a liquid limit of not over 35 and a plasticity index of not over six. Test for liquid limit and plasticity index shall be in accordance with AASHO designations T-89 and T-91 respectively.
(B) Concrete.
(1) Cement. Cement shall conform to ASTM-C-150, C-175 or C-595. The cement supplier shall submit to the engineer a certification that the cement used on the project conforms to the applicable specifications with complete mill analysis for every 200 tons used.
(2) Aggregate. Aggregate shall conform to ASTM-C-33 (see American Concrete Paving Association technical bulletin no. 15) for optimum size course aggregate.
(3) Admixtures. Air entraining admixtures shall conform to ASTM-C-260. Type A water reducing admixtures (normal setting) shall conform to ASTM-C-494. Type D water reducing admixtures (retarders) shall conform to ASTM-C-494. Type E water reducing admixtures (accelerating) shall conform to ASTM-C-494. Fly ash shall conform to ASTM-C-618 type F with the following restriction: sulfur trioxide shall not exceed 5%, and loss of ignition shall not exceed 5%.
(4) Materials for curing concrete. Membrane curing compounds for concrete shall be the pigmented type conforming to the requirements of AASHTO-M-148 and/or ASTM-C-309. Membrane curing compounds for concrete may be transparent with a fugitive dye.
(5) Joint filling compound. Where joints are required to be filled, filling material for filling pavement joints shall be hot poured rubber asphalt joint filling compound conforming to AASHTO-M-173 or federal specifications SS-S-164 or SS-S-1401a.
(6) Water. If the water is of questionable quality, it shall be tested in accordance with AASHTO-T-26, Standard Method Of Test For Quality Of Water To Be Used In Concrete.
(7) Strength required. All concrete shall have a specified compressive strength of 4,000 psi and shall be determined by ACI standard 318-71, §§ 4.3.3 and 4.3.4. In nonfrost areas, lower fc’ values may be used in conformity with local practice and performance. For design charts using lower fc’ values, contact ACPA.
(8) Air content. The air content of the plastic concrete shall be uniform and shall be 5.5% plus or minus 1.5% (5.5% ± 1.5%).
(9) Slump. The mixture shall contain no more water than is necessary to produce concrete which is workable and plastic. The minimum slump necessary to place the concrete satisfactorily shall be used. Slumps should be maintained so as not to exceed four and one-half inches for nonvibrated placement and three inches for vibrated placement.
(C) Asphalt. All materials shall conform to the latest Colorado Standard Specifications For Road And Bridge Construction prepared by the State Department of Highways.
(Ord. 2(1983) § 1; 1997 Code; Ord. 29(2005) § 67)