Click here to purchase

1.1 This specification covers materials for use as chemical admixtures to be added to hydraulic-cement concrete mixtures in the field for the purpose or purposes indicated for the eight types as follows:

1.1.1 Type AWater-reducing admixtures,

1.1.2 Type BRetarding admixtures,

1.1.3 Type CAccelerating admixtures,

1.1.4 Type DWater-reducing and retarding admixtures,

1.1.5 Type EWater-reducing and accelerating admixtures,

1.1.6 Type FWater-reducing, high range admixtures,

1.1.7 Type GWater-reducing, high range, and retarding admixtures, and

1.1.8 Type SSpecific performance admixtures.

1.2 This specification stipulates tests of an admixture with suitable concreting materials as described in 11.1-11.3 or with cement, pozzolan, aggregates, and an air-entraining admixture proposed for specific work (11.4). Unless specified otherwise by the purchaser, the tests shall be made using concreting materials as described in 11.1-11.3.

Note 1 – It is recommended that, whenever practicable, tests be made using the cement, pozzolan, aggregates, air-entraining admixture, and the mixture proportions, batching sequence, and other physical conditions proposed for the specific work (11.4) because the specific effects produced by chemical admixtures may vary with the properties and proportions of the other ingredients of the concrete. For instance, Types F and G admixtures may exhibit much higher water reduction in concrete mixtures having higher cement factors than that listed in 12.1.1.

Mixtures having a high range water reduction generally display a higher rate of slump loss. When high-range admixtures are used to impart increased workability (6 to 8-in. slump [150 to 200mm]), the effect may be of limited duration, reverting to the original slump in 30 to 60 min depending on factors normally affecting rate of slump loss. The use of chemical admixtures to produce high-slump (flowing) concrete is covered by Specification C1017/C1017M.

Note 2 – The purchaser should ensure that the admixture supplied for use in the work is equivalent in composition to the admixture subjected to test under this specification (see Section 6, Uniformity and Equivalence).

Note 3 – Admixtures that contain relatively large amounts of chloride may accelerate corrosion of prestressing steel. Compliance with the requirements of this specification does not constitute assurance of acceptability of the admixture for use in prestressed concrete.

1.3 This specification provides for three levels of testing.

1.3.1 Level 1During the initial approval stage, proof of compliance with the performance requirements defined in Table 1 demonstrates that the admixture meets the requirements of this specification. Admixtures (except for Types B, C, E, and S) shall qualify for provisional compliance when the physical requirements and any of the alternative compressive strength requirements in Table 1 are met. If subsequent test results at 6 months or one year fail to meet the standard requirement of 100 % of reference strength, the compliance of the admixture to this standard is withdrawn and all users of the admixture shall be notified immediately. Uniformity and equivalence tests of Section 6 shall be carried out to provide results against which later comparisons can be made (See Note 4).

Note 4 – Allowing for provisional compliance while retaining longer term compressive strength requirements promotes more rapid qualification of new materials, but also provides assurance that new admixture technologies will not exhibit unexpected longer term performance. The alternative compressive strength requirements in Table 1 are based on statistical analysis of 103 Specification C494/C494M evaluation tests. The alternative requirements correspond to a 99 % probability of passing subsequent test age requirements.

1.3.2 Level 2Limited retesting is described in 5.2, 5.2.1 and 5.2.2. Proof of compliance with the requirements of Table 1 demonstrates continued conformity of the admixture with the requirements of the specification.

1.3.3 Level 3For acceptance of a lot or for measuring uniformity within or between lots, when specified by the purchaser, the uniformity and equivalence tests of Section 6 shall be used.

1.4 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.

1.5 The text of this standard references notes and footnotes which provide explanatory material. These notes and footnotes (excluding those in tables and figures) shall not be considered as requirements of the standard.

1.6 The following precautionary caveat pertains only to the test method sections, Sections 11-18 of this Specification: This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

TABLE 1 Physical RequirementsA

Type A,
Water
Reducing
Type B,
Retarding
Type C,
Acceler-
ating
Type D,
Water
Reducing
and
Retarding
Type E,
Water
Reducing
and
Accelerating
Type F,
Water
Reducing,
High Range
Type G,
Water
Reducing,
High
Range
and Retarding
Type S
Specific
Performance
Water content, max, % of control 95 95 95 88 88
Time of setting, allowable deviation from control, h:min:
Initial: at least 1:00 later 1:00 earlier 1:00 later 1:00 earlier 1:00 later
not more than 1:00 earlier
nor 1:30
later
3:30 later 3:30 earlier 3:30 later 3:30 earlier 1:00 earlier
nor 1:30
later
3:30 later 1:00 earlier
nor 1:30
later
Final: at least 1:00 earlier 1:00 earlier
not more than 1:00 earlier
nor 1:30
later
3:30 later 3:30 later 1:00 earlier
nor 1:30
later
3:30 later 1:00 earlier
nor 1:30
later
Compressive strength, min, % of control:B
1 day 140 125
3 days 110 90 125 110 125 125 125 90
7 days 110 90 100 110 110 115 115 90
28 days 110
(120)C
90 100 110
(120)C
110 110
(120)C
110
(120)C
90
90 days (117)C n/a n/a (117)C n/a (117)C (117)C n/a
6 months 100
(113)C
90 90 100
(113)C
100 100
(113)C
100
(113)C
90
1 year 100 90 90 100 100 100 100 90
Flexural strength, min, % control:B
3 days 100 90 110 100 110 110 110 90
7 days 100 90 100 100 100 100 100 90
28 days 100 90 90 100 100 100 100 90
Length change, max shrinkage (alternative requirements):D
Percent of control 135 135 135 135 135 135 135 135
Increase over control 0.010 0.010 0.010 0.010 0.010 0.010 0.010 0.010
Relative durability
factor, minE
80 80 80 80 80 80 80 80

A The values in the table include allowance for normal variation in test results. The object of the 90 % compressive strength requirement for a Type B amd Type S admixture is to require a level of performance comparable to that of the reference concrete.

B The compressive and flexural strength of the concrete containing the admixture 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 admixture under test shall not decrease with age.

C Alternative requirement. If the physical requirements are met and any of the measured relative strengths are greater than the requirement in parentheses, the admixture shall be considered provisionally qualified until the 1-year strength test results are obtained.

D Alternative requirements, see 17.1.4, % of control limit applies when length change of control is 0.030 % or greater; increase over control limit applies when length change of control is less than 0.030 %.

E This requirement is applicable only when the admixture is to be used in air-entrained concrete which may be exposed to freezing and thawing while wet.

Product Details

Published:
07/01/2012
Number of Pages:
10
File Size:
1 file , 150 KB
Redline File Size:
2 files , 250 KB