I. Pavement Patching Mix (Class A, Early Strength) Portland cement concrete shall conform to DelDOT Standard Specifications for Road and Bridge Construction, August 2016 Edition, or as amended., except it shall have a minimum compressive strength of 2,000 psi in six hours at an ambient temperature of 70 degrees F. The following are the contents of the Portland Cement Concrete: Water/cement ratio by weight: 0.40 Air content (%): 4 - 7 percent Aggregate size: Delaware No.8 stone Slump: 2 - 5 inches The vendor, in order to accomplish 2,000 psi compressive strength in 6 hours, shall establish an actual combination of weights and proportion of admixtures as required by the ambient temperature, humidity and wind conditions. The minimum 28-day Compressive Strength of this mix shall be 4,500 psi. Standard Mix (Class B) Portland cement shall conform to DelDOT Standard Specifications for Road and Bridge Construction, August 2016 Edition, or as amended. The following are the contents of the Portland Cement Concrete: Water/cement ratio by weight: 0.45 Air content: 4 to 7 percent Aggregate size: Delaware No. 8 stone Slump: 2 to 7 inches The vendor, in order to accomplish 2,000 psi compressive strength in 72 hours, shall establish an actual combination of weights and proportions of Admixtures as required by the ambient temperature, humidity and wind conditions. The minimum 28-day Compressive Strength of this mix shall be 3,000 psi. Class A & Class B, use rapid-set concrete patch materials in strict conformance with manufacture’s recommendations and that conform to the following: A. Use a blend of selected Portland cements, specially graded aggregates, admixtures for controlling setting time, water reducers for workability, and an accelerator for the patch Materials. B. Supply patch materials in a factory-blended bag/container accompanied with the manufacturer’s recommendations. C. Add aggregate to the mix conforming to ASTM C33, at a rate recommended by the manufacturer. Use Delaware No. 8 stone for this purpose as specified under Standard Specification Section 1004 – Coarse Aggregate. Mix pre-blended patch mixes in strict accordance with the manufacturer’s proportions and recommendations, using an on-site mechanical mixer.
