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1 <br /> D. When high-early-strength Portland cement is permitted, the same strength <br /> requirements shall apply except that the indicated strengths shall be attained at <br /> seven (7) days instead of twenty-eight (28) days. <br /> E. If during the progress of the work it is impossible to secure concrete of the required <br /> e workability and strength with the materials being furnished, the Engineer may order <br /> such changes in proportions or materials, or both, as may be necessary to secure <br /> the desired properties. All changes so ordered shall be made at the Contractors <br /> expense. <br /> F. If during the progress of the work the Contractor desires to use materials other <br /> than those originally approved, or if the materials from the sources originally <br /> approved change in characteristics, the Contractor shall, at his own expense, have <br /> made new acceptance tests of aggregates and establishment of new basic <br /> mixtures and submit them to the Engineer for approval. <br /> G. Consistency of the concrete as measured by the ASTM Designation C143 shall be <br /> as shown in (Table B). <br /> TABLE B <br /> Slump (inches) <br /> Portion of Structure Max.* Min. <br /> Pavement and slabs on ground 3 2 <br /> Plain footings, gravity walls, <br /> slabs and beams 3 2 <br /> Heavy reinforced foundation <br /> walls and footings 4 2 <br /> Thin reinforced walls and columns 4 2 <br /> May be increased 1-inch if proper method of consolidation is used. <br /> H. Concrete shall be of such consistency and mix composition that it can be readily <br /> worked into the corners and angles of the forms and around the reinforcement, <br /> inserts, and wall castings without permitting materials to segregate or free water to <br /> collect on the surface, due consideration being given to the methods of placing and <br /> compacting. <br /> No excessively wet concrete will be permitted, and if at any time concrete of such <br /> consistency beyond the limits of Table B is delivered to the job, the Engineer may <br /> direct the Contractor to reject same or to add extra cement for which no additional <br /> payment will be made. A supply of the approved cement shall be kept available at <br /> 1 the site for this purpose. Drivers of transit-mix trucks shall add no additional water <br /> except that established for the design. Failure to comply with this requirement <br /> shall be justification for rejecting the concrete. <br /> 1 J. The entrained air, as measured by the Pressure Method, ASTM C231, shall be as <br /> shown in (Table C). <br /> TABLE C <br /> Nominal Maximum Size Total Air Measured at <br /> of Coarse Aqqreqate(in) Discharge from truck (%) <br /> 1 05108 03300-3 05-4893 <br />