ASTM C688-08e1

1.1 This specification covers methods to investigate the effectiveness of a material to beneficially change the properties of hydraulic cements when the material is incorporated during manufacture of the cement.

1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.3 The effect of additions in cement may markedly change properties other than those they are intended to modify. This specification is designed to test for such changes. Table 1 sets forth values for those properties of cement pastes and mortars that would permit a judgment of the changes effected by an addition. Likewise, Table 2 sets forth similar criteria for concrete. Certain additions may be found effective for more than one purpose as indicated in 3.1.4 and 3.1.5.

TABLE 1 Criteria for Evaluating Neat Cement and Mortar Containing Functional Cement Additions

^A The minus sign indicates that the percentage of water required shall be less than that of the control cement by at least the indicated percentage points.

^B Or 50 % later, whichever is the lesser.

^C Either Vicat or the Gillmore time of setting method shall be used at the choice of the manufacturer.

^D The compressive strength of mortar containing the test cement shall be not less than 95 % of that attained at any previous test age. The objective of this limit is to require that the strength of mortar containing the addition under test shall not decrease with age.

^E In cases where the accelerated set time only is required, the strength can be reduced to 100 % of the control.

^F The grand average of the 1, 3, 7, and 28-day strengths shall be not less than 95 % of the grand average for the corresponding control cement.

TABLE 2 Criteria for Evaluating Concrete Containing Functional Cement Additions^A

^A The values in the table are intended to allow for normal variation in test results. For example, the object of the 90 % compressive strength requirement for a retarding addition is to require a level of performance comparable to that of the reference concrete.

^B Or 50 % later, whichever is the lesser.

^C The compressive and flexural strength of the concrete containing the addition under test at any test age shall be not less than 90 % of that attained at any previous test age. The objective of this limit is to require that the compressive or flexural strength of the concrete containing the addition under test shall not decrease with age.

^D One-day strengths applicable only to Type III cement. One-year strength tests shall be made; however, the addition may be approved after completion of the 3-month strength results, at the discretion of the purchaser.

^E In cases where the accelerated set time only is required, the strength can be reduced to 100 % of the control.

^F This requirement is applicable only when the addition is to be used in air-entrained concrete.