Agmt13 Pacific Electric Contracting, Inc.

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B. Temperature of mixed concrete, immediately prior to placement, shall not be less than 50° F, nor more than 90°F. Aggregates and water shall be heated or cooled at the mixing plant by supplier as necessary to produce concrete within these limits. Neither aggregates nor mixing water shall be heated to exceed 150°F. C. No additionat mixing water shali be incorporated into the concrete during transport or after arrival at the work site unless such water is specifically authorized by the Engineer. If authorization to add mixing water is obtained and mixing water is added to the mix, the mixer drum shall then be revolved a minimum of thirty (30) revolutions. D. Hand mixing of Portland Cement Concrete shall not be allowed except upon prior written approval. E. Where a portion of existing concrete improvements is to be reconstructed, the section to be removed shall first be a cut with an approved concrete saw to a minimum depth of one-half the depth of the existing concrete at the first score line beyond the area to be replaced. F. Where concrete removal is required, it shall be removed to the nearest score line of joints. G. Prior to placing concrete for concrete structures, Contractor shall first secure approval of the forms and any required reinforcement. PART 2- PRODUCTS 2.01 AGGREGATE FOR PORTLAND CEMENT CONCRETE A. Aggregates for Portland Cement Concrete shall conform to the requirements of Section 90- 2.02A and B of the State Standard Specification. B. Unless otherwise specified or called for on the plans for the work, aggregate size and gradation for Portland Cement Concrete shall conform to the requirements of Section 90-3.04 of the State Standard Specifications for one inch (1") maximum combined aggregate. 2.02 WATER FOR PORTLAND CEMENT CONCRETE A. Water for mixing and curing concrete and for washing aggregates shall conform to the requirements of Section 90-2.03 of the State Standard Specifications. 2.03 CEMENT FOR PORTLAND CEMENT CONCRETE A. Cement for Portland Cement Concrete to be placed in roadway improvements such as curbs, gutters, walks, valley gutters, driveways, surface and subsurface pads or slabs shall be Type V or Type II (modified) cement conforming to the requirements of ASTM Designation C150, with the following modifications: 1. The cement shall not contain more than 0.60% by weight of alkalies, calculated as the percentage of Na20 plus 0.658 times the percentage of K20 when determined by either direct 4 intensity flame photometry or by the atomic absorption method. The instrument and procedure used shall be qualified as to precision and accuracy in accordance with the requirements of ASTM Designation C114. 2. The autoclave expansion shall not exceed 0.50%. 3. Mortar, containing the Portland Cement to be used and the sand, when tested in accordance with Test Method No. Calif 527, shall not expand in water more than 0.010% and shall have an air content less than 048%. 4. Allowable tri-calcium Aluminate (C3A) by weight shall not exceed 5%. Allowable tetracalcium alumino ferrite plus twice the tricalcium aluminate (C4AF+2C3A) by weight shall not exceed 25%. The sulfate expansion test (ASTM C452) may be used in lieu of the above chemical requirements, provided the sulfate expansion does not exceed 0.040% at 14 days (max). CONCRETE IMPROVEMENTS 02550-3 EAST BAYSHRORE ROAD STREET LIGHTING PROJECT