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When expressing compounds, C = CaO, S = SiO2, A = A^Oa, F = Fe2O3. For example, C3A = 3CaOAl2O3.
Titanium dioxide and phosphorus pentoxide (??2 and P2O5) shall be included with the A^O3 content. The value historically and traditionally used for Al2O3 in calculating potential compounds for specification purposes is the ammonium hydroxide group minus ferric oxide (R2O3 - Fe2O3) as obtained by classical wet chemical methods. This procedure includes as A^O3 the TiO2, P2O5 and other trace oxides which precipitate with the ammonium hydroxide group in the classical wet chemical methods. Many modern instrumental methods of cement analysis determine aluminum or aluminum oxide directly without the minor and trace oxides included by the classical method. Consequently, for consistency and to provide comparability with historic data and among various analytical methods, when calculating poten-
tial compounds for specification purposes, those using methods which determine Al or Al2O3 directly should add to the determined Al2O3 weight quantities of P2O5. TiO2 and any other oxide except Fe2O3 which would precipitate with the ammonium hydroxide group when analyzed by the classical method and which is present in an amount of 0.05 weight % or greater. The weight percent of minor or trace oxides to be added to Al2O3 by those using direct methods may be obtained by actual analysis of those oxides in the sample being tested or estimated from historical data on those oxides on cements from the same source, provided that the estimated values are identified as such.
When the ratio of percentages of aluminum oxide to ferric oxide is 0.64 or more, the percentages of tricalcium silicate, dicalcium silicate, tricalcium aluminate and tetracalcium aluminoferrite shall be calculated from the chemical analysis as follows:
Tricalcium silicate = (4.071 x % CaO) - (7.600 x % SiO2) - (6.718 x % A^) - (1.430 x % Fe2O3) - (2.852 x % SO3) Dicalcium silicate = (2.867 x % SiO2) - (0.7544 x % C3S)
Tricalcium aluminate = (2.650 x % A^O3) - (1.692 x % Fe2O3)
Tetracalcium aluminoferrite = 3.043 x % Fe2O3
When the alumina-ferric oxide ratio is less than 0.64, a calcium aluminoferrite solid solution (expressed as ss(C4AF + C2F)) is formed. Contents of this solid solution and of tricalcium silicate shall be calculated by the following formulas:
ss(C4AF + C2F) = (2.100 x % Al2O3) + (1.702 x % Fe2O3)
Tricalcium silicate = (4.071 x % CaO) - (7.600 x % SiO2) - (4.479 x % Al2O3) - (2.859 x % Fe2O3) - (2.852 x % SO3).
No tricalcium aluminate will be present in cements of this composition. Dicalcium silicate shall be calculated as previously shown.
In the calculation of all compounds the oxides determined to the nearest 0.1% shall be used.
All values calculated as described in this note shall be reported to the nearest 1%.
C The optional limit for heat of hydration in Table C-8 shall not be requested when this optional limit is requested.
D This limit may be specified when the cement is to be used in concrete with aggregates that may be deleteriously reactive. Reference should be made to Specification C 33 for suitable criteria of deleterious reactivity.
10.1 Inspection of the material shall be made as agreed upon by the purchaser and the seller as part of the purchase contract.
11.1 The cement may be rejected if it fails to meet any of the requirements of this specification.
11.2 Cement remaining in bulk storage at the mill, prior to shipment, for more than 6 months, or cement in bags in local storage in the hands of a vendor for more than 3 months, after completion of tests, may be retested before use and may be rejected if it fails to conform to any of the requirements of this specification.
11.3 Packages shall identify the mass contained as net weight. Packages more than 2 percent below the weight marked thereon may be rejected; and if the average weight of packages in any shipment, as shown by weighing 50 packages taken at random, is less than that marked on the packages, the entire shipment may be rejected.
Cement; Portland Cement C-27
TABLE C-7 Standard Physical Requirements
Cement TypeA I IA II IIA III IIIA IV V
Air content of mortar,B volume %:
max 12 22 12 22 12 22 12 12
min --- 16 --- 16 --- 16 --- ---
Fineness,C specific surface, m2/kg