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I I D. I E. I I F. I I G. I I I I H. I I I. I I I J. I I 06/07 I When high-early-strength Portland cement is permitted, the same strength requirements shall apply except that the indicated strengths shall be attained at seven (7) days instead of twenty-eight (28) days. If during the progress of the work it is impossible to secure concrete of the required workability and strength with the materials being furnished, the Engineer may order such changes in proportions or materials, or both, as may be necessary to secure the desired properties. All changes so ordered shall be made at the Contractor's expense. If during the progress of the work the Contractor desires to use materials other than those originally approved, or if the materials from the sources originally approved change in characteristics, the Contractor shall, at his own expense, have made new acceptance tests of aggregates and establishment of new basic mixtures and submit them to the Engineer for approval. Consistency of the concrete as measured by the ASTM Designation C143 shall be as shown in (Table B). TABLE B Portion of Structure Slump Max.* (inches) Min. Pavement and slabs on ground 3 2 Plain footings, gravity walls, slabs and beams 3 2 Heavy reinforced foundation walls and footings 4 2 Thin reinforced walls and columns 4 2 * May be increased i-inch if proper method of consolidation is used. Concrete shall be of such consistency and mix composition that it can be readily worked into the corners and angles of the forms and around the reinforcement, inserts, and wall castings without permitting materials to segregate or free water to collect on the surface, due consideration being given to the methods of placing and compacting. No excessively wet concrete will be permitted, and if at any time concrete of such consistency beyond the limits of Table B is delivered to the job, the Engineer may direct the Contractor to reject same or to add extra cement for which no additional payment will be made. A supply of the approved cement shall be kept available at the site for this purpose. Drivers of transit-mix trucks shall add no additional water except that established for the design. Failure to comply with this requirement shall be justification for rejecting the concrete. The entrained air, as measured by the Pressure Method, ASTM C231, shall be as shown in (Table C). TABLE C Nominal Maximum Size of Coarse Aqqreqate(in) Total Air Measured at Discharqe from truck (%) 03300-3 03-4197