Delete materials below not required. Revise to suit Project.
Portland cement: ASTM C150, Type I or III.
Select Portland cement color from options in subparagraph below. Mixing with white cement will improve color uniformity of gray cement. White cement has greater color consistency than gray cement and should be used for pastel colors. For darker colors, the variations of gray cement have less effect on the final color hue.
For surfaces exposed to view in finished structure, use [gray] [and] [white], same type, brand, and mill source throughout the precast concrete production.
Standard gray Portland cement may be used for non-exposed backup concrete.
B.Supplementary Cementitious Materials.
Select mineral or cementitious admixtures from four paragraphs below. Where appearance is an important factor, it is recommended that fly ash, silica fume and ground slag not be permitted.
Fly Ash Admixture: ASTM C 618, Class C or F with maximum loss on ignition of 3 percent.
Metakaolin Admixture: ASTM C 618, Class N.
Silica Fume Admixture: ASTM C 1240 with optional chemical and physical requirement.
Ground Granulated Blast-Furnace Slag: ASTM C989, Grade 100 or 120.
ASTM C 33 limits deleterious substances in coarse aggregate depending on climate severity and in-service location of concrete. Class 5S is the most restrictive designation for architectural concrete exposed to severe weathering. PCI MNL 117 establishes stricter limits on deleterious substances for fine and coarse aggregates.
Normal-Weight Aggregates: Except as modified by PCI MNL 117, ASTM C 33, with coarse aggregates complying with Class 5S. Provide and stockpile fine and coarse aggregates for each type of exposed finish from a single source (pit or quarry) for entire project.
Revise subparagraph below and add descriptions of selected coarse- and fine-face mix aggregate colors, sizes, and sources if required.
Face-Mix Coarse Aggregates: Selected, hard, and durable; free of material that reacts with cement or causes staining; to match selected finish sample.
Retain one option from first subparagraph below or insert gradation and maximum aggregate size if known. Fine and coarse aggregates are not always from same source.
Gradation: [Uniformly graded] [Gap graded] [To match design reference sample].