Specifications include, but are not limited to: Portland Cement Concrete for street maintenance projects. 6. Mix Number: • M-4, C-4, C-4WR, C-4 WR-C20, C-4 WR (modified) in accordance with Iowa DOT Standard Specifications Section 2301 and Iowa DOT Materials I. M. 529 as requested by the City. • Air entraining admixture: produce 6.5% + 1.0% air voids in fresh concrete measured by pressure method. 7. Proportion of adjustments: • Basis: When actual quantity of concrete is more than one hundred and one percent (101%) or less than ninety-nine percent (99%) of calculated quantity or if combination of materials does not produce quality of concrete specified. • Fine aggregate shall not exceed fifty percent (50%) of total aggregate in any adjustment. • Do not exceed maximum water-cement ratio specified. 8. Water quality and concrete consistency: • Use proper amount of mixing water to produce concrete of uniform consistency; adapt to mix, characteristics of materials used, methods of consolidation, weather conditions and slope of finished surface. • Modify proportion if maximum water-cement ratio does not produce workability; increase cement to aggregate proportion to produce specified degree of workability without exceeding maximum water-cement ratio.