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This chapter shall apply to concrete, including:

(a) Properties to be used for design

(b) Durability requirements

This chapter shall apply to durability requirements for grout used for bonded tendons in accordance with 19.4.
The value of fc' shall be specified in construction documents and shall be in accordance with (a) through (c):

(a) Limits in Table 19.2.1.1

(b) Durability requirements in Table 19.3.2.1

(c) Structural strength requirements

Table 19.2.1.1—Limits for fc'

Application Concrete Minimum fc', psi Maximum fc', psi
General Normalweight and lightweight 2500 None
Special moment frames and special structural walls Normalweight 3000 None
Lightweight 3000 5000[1]

[1]The limit is permitted to be exceeded where demonstrated by experimental evidence that members made with lightweight concrete provide strength and toughness equal to or exceeding those of comparable members made with normalweight concrete of the same strength.

The specified compressive strength shall be used for proportioning of concrete mixtures in 26.4.3 and for testing and acceptance of concrete in 26.12.3.
Unless otherwise specified, fc' shall be based on 28-day tests. If other than 28 days, test age for fc' shall be indicated in the construction documents.
Modulus of elasticity, Ec, for concrete shall be permitted to be calculated as (a) or (b):

(a) For values of wc between 90 and 160 lb/ft3

(19.2.2.1.a)

(b) For normalweight concrete

(19.2.2.1.b)
Modulus of rupture, fr, for concrete shall be calculated by:
(19.2.3.1)

where the value of λ is in accordance with 19.2.4.

To account for the properties of lightweight concrete, a modification factor λ is used as a multiplier of in all applicable provisions of this Code.
The value of λ shall be based on the composition of the aggregate in the concrete mixture in accordance with Table 19.2.4.2 or as permitted in 19.2.4.3.

Table 19.2.4.2—Modification factor λ

Concrete Composition of aggregates λ
All-lightweight Fine: ASTM C330 Coarse: ASTM C330 0.75
Lightweight, fine blend Fine: Combination of ASTM C330 and C33 Coarse: ASTM C330 0.75 to 0.85[1]
Sand-lightweight Fine: ASTM C33 Coarse: ASTM C330 0.85
Sand-lightweight, coarse blend Fine: ASTM C33 Coarse: Combination of ASTM C330 and C33 0.85 to 1[2]
Normalweight Fine: ASTM C33 Coarse: ASTM C33 1

[1]Linear interpolation from 0.75 to 0.85 is permitted based on the absolute volume of normalweight fine aggregate as a fraction of the total absolute volume of fine aggregate.

[2]Linear interpolation from 0.85 to 1 is permitted based on the absolute volume of normalweight coarse aggregate as a fraction of the total absolute volume of coarse aggregate.

If the measured average splitting tensile strength of lightweight concrete, fct, is used to calculate λ, laboratory tests shall be conducted in accordance with ASTM C330 to establish the value of fct and the corresponding value of fcm and λ shall be calculated by:
(19.2.4.3)

The concrete mixture tested in order to calculate λ shall be representative of that to be used in the Work.

The licensed design professional shall assign exposure classes in accordance with the severity of the anticipated exposure of members for each exposure category in Table 19.3.1.1.

Table 19.3.1.1—Exposure categories and classes

Category Class Condition
Freezing and thawing (F) F0 Concrete not exposed to freezing-and-thawing cycles
F1 Concrete exposed to freezing-and-thawing cycles with limited exposure to water
F2 Concrete exposed to freezing-and-thawing cycles with frequent exposure to water
F3 Concrete exposed to freezing-and-thawing cycles with frequent exposure to water and exposure to deicing chemicals
Sulfate (S) Water-soluble sulfate (SO42-) in soil, percent by mass[1] Dissolved sulfate (SO42-) in water, ppm[2]
S0 SO42-< 0.10 SO42-< 150
S1 0.10 ≤ SO42-< 0.20 150 ≤ SO42-< 1500 or seawater
S2 0.20 ≤ SO42-≤ 2.00 1500 ≤ SO42-≤ 10,000
S3 SO42-> 2.00 SO42->10,000
In contact with water (W) W0 Concrete dry in service Concrete in contact with water and low permeability is not required
W1 Concrete in contact with water and low permeability is required
Corrosion protection of reinforcement (C) C0 Concrete dry or protected from moisture
C1 Concrete exposed to moisture but not to an external source of chlorides
C2 Concrete exposed to moisture and an external source of chlorides from deicing chemicals, salt, brackish water, seawater, or spray from these sources

[1]Percent sulfate by mass in soil shall be determined by ASTM C1580.

[2]Concentration of dissolved sulfates in water, in ppm, shall be determined by ASTM D516 or ASTM D4130.

Based on the exposure classes assigned from Table 19.3.1.1, concrete mixtures shall conform to the most restrictive requirements in Table 19.3.2.1.

Table 19.3.2.1—Requirements for concrete by exposure class

Exposure class Maximum w/cm[1] Minimum fc' psi Additional requirements Limits on cementitious materials
Air content
F0 N/A 2500 N/A N/A
F1 0.55 3500 Table 19.3.3.1 N/A
F2 0.45 4500 Table 19.3.3.1 N/A
F3 0.40[2] 5000[2] Table 19.3.3.1 26.4.2.2(b)
Cementitious materials[3] — Types Calcium chloride admixture
ASTM C150 ASTM C595 ASTM C1157
S0 N/A 2500 No type restriction No type restriction No type restriction No restriction
S1 0.50 4000 II[4][5] Types IP, IS, or IT with (MS) designation MS No restriction
S2 0.45 4500 V[5] Types IP, IS, or IT with (HS) designation HS Not permitted
S3 0.45 4500 V plus pozzolan or slag cement[6] Types IP, IS, or IT with (HS) designation plus pozzolan or slag cement[6] HS plus pozzolan or slag cement[6] Not permitted
W0 N/A 2500 None
W1 0.50 4000 None
Maximum water-soluble chloride ion (Cl) content in concrete, percent by weight of cement[7] Additional provisions
Nonprestressed concrete Prestressed concrete
C0 N/A 2500 1.00 0.06 None
C1 N/A 2500 0.30 0.06
C2 0.40 5000 0.15 0.06 Concrete cover[8]

[1]The maximum w/cm limits in Table 19.3.2.1 do not apply to lightweight concrete.

[2]For plain concrete, the maximum w/cm shall be 0.45 and the minimum fc' shall be 4500 psi.

[3]Alternative combinations of cementitious materials to those listed in Table 19.3.2.1 are permitted when tested for sulfate resistance and meeting the criteria in 26.4.2.2(c).

[4]For seawater exposure, other types of portland cements with tricalcium aluminate (C3A) contents up to 10 percent are permitted if the w/cm does not exceed 0.40.

[5]Other available types of cement such as Type I or Type III are permitted in Exposure Classes S1 or S2 if the C3A contents are less than 8 percent for Exposure Class S1 or less than 5 percent for Exposure Class S2.

[6]The amount of the specific source of the pozzolan or slag cement to be used shall be at least the amount that has been determined by service record to improve sulfate resistance when used in concrete containing Type V cement. Alternatively, the amount of the specific source of the pozzolan or slag cement to be used shall be at least the amount tested in accordance with ASTM C1012 and meeting the criteria in 26.4.2.2(c).

[7]Water-soluble chloride ion content that is contributed from the ingredients including water, aggregates, cementitious materials, and admixtures shall be determined on the concrete mixture by ASTM C1218 at age between 28 and 42 days.

[8]Concrete cover shall be in accordance with 20.6.

Normalweight and lightweight concrete subject to freezing-and-thawing Exposure Classes F1, F2, or F3 shall be air entrained. Except as permitted in 19.3.3.3, air content shall conform to Table 19.3.3.1.

Table 19.3.3.1—Total air content for concrete exposed to cycles of freezing and thawing

Nominal maximum aggregate size, in. Target air content, percent
F1 F2 and F3
3/8 6 7.5
1/2 5.5 7
1/3 5 6
1 4.5 6
1-1/2 4.5 5.5
2 4 5
3 3.5 4.5
Concrete shall be sampled in accordance with ASTM C172, and air content shall be measured in accordance with ASTM C231 or ASTM C173.
For fc' exceeding 5000 psi, reduction of air content indicated in Table 19.3.3.1 by 1.0 percentage point is permitted.
The maximum percentage of pozzolans, including fly ash and silica fume, and slag cement in concrete assigned to Exposure Class F3, shall be in accordance with 26.4.2.2(b).
Alternative combinations of cementitious materials to those listed in 19.3.2 are permitted when tested for sulfate resistance. Testing and acceptance criteria shall conform to Table 26.4.2.2(c).
Water-soluble chloride ion content of grout for bonded tendons shall not exceed 0.06 percent when tested in accordance with ASTM C1218, measured by mass of chloride ion to mass of cement.
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