Adopts With Amendments:

ACI 318 2019

Part 1: General

Part 2: Loads & Analysis

Part 3: Members

Part 4: Joints/Connections/Anchors

Part 5: Earthquake Resistance

Part 6: Materials & Durability

Part 7: Strength & Serviceability

Part 8: Reinforcement

Part 9: Construction

Part 10: Evaluation

REFERENCES & Appendices

Heads up: There are no amended sections in this chapter.
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 in accordance with (a) through (d):
(a) Limits for fc' in Table 19.2.1.1. Limits apply to both normalweight and lightweight concrete.
(b) Durability requirements in Table 19.3.2.1
(c) Structural strength requirements
(d) fc' for lightweight concrete in special moment frames and special structural walls, and their foundations, shall not exceed 5000 psi, unless 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.
Application Minimum fc', psi
General 2500
Foundations for structures assigned to SDC A, B, or C 2500
Foundations for Residential and Utility use and occupancy classification with stud bearing wall construction two stories or less assigned to SDC D, E, or F 2500
Foundations for structures assigned to SDC D, E, or F other than Residential and Utility use and occupancy classification with stud bearing wall construction two stories or less 3000
Special moment frames Special structural walls with Grade 60 or 80 reinforcement 3000
Special structural walls with Grade 100 reinforcement 5000
Precast-nonprestressed driven piles Drilled shafts 4000
Precast-prestressed driven piles 5000
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.
It shall be permitted to calculate Ec in accordance with (a) or (b):
(a) For values of wc between 90 and 160 lb/ft3
(19.2.2.1.a)
(19.2.2.1.b)
It shall be permitted to specify Ec based upon testing of concrete mixtures to be used in the Work in accordance with (a) through (c):
(a) Specified Ec shall be used for proportioning concrete mixtures in accordance with 26.4.3.
(b) Testing to verify that the specified Ec has been achieved shall be conducted, and results shall be provided with the mixture submittal.
(c) Test age of measurement of Ec shall be 28 days or as indicated in the construction documents.
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.
Except as required in Table 25.4.2.5, the value of λ shall be determined using Table 19.2.4.1(a) based on the equilibrium density, wc, of the concrete mixture used in design, or Table 19.2.4.1(b) based on the composition of the aggregate in the concrete mixture assumed in the design.
Table 19.2.4.1(a)—Values of λ for lightweight concrete based on equilibrium density
wc, lb/ft3 λ
≤ 100 0.75 (a)
100 < wc ≤ 135 0.0075wc ≤ 1.0 (b)
> 135 1.0 (c)
Table 19.2.4.1(b)—Values of λ for lightweight concrete based on composition of aggregates
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]
[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 aggregate.
It shall be permitted to take λ as 0.75 for lightweight concrete.
The value of λ shall be taken as 1.0 for normalweight concrete.
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
W1 Concrete in contact with water where low permeability is not required
W2 Concrete in contact with water where 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[1,2] 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 for concrete or Table 19.3.3.3 for shotcrete N/A
F2 0.45 4500 Table 19.3.3.1 for concrete or Table 19.3.3.3 for shotcrete N/A
F3 0.40[3] 5000[3] Table 19.3.3.1 for concrete or Table 19.3.3.3 for shotcrete 26.4.2.2(b)
Cementitious materials[4] — 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[5][6] Types with (MS) designation MS No restriction
S2 0.45 4500 V[6] Types with (HS) designation HS Not permitted
S3 Option 1 0.45 4500 V plus pozzolan or slag cement[7] Types with (HS) designation plus pozzolan or slag cement[7] HS plus pozzolan or slag cement[7] Not permitted
Option 2 0.40 5000 V[8] Types with (HS) designation HS Not permitted
W0 N/A 2500 None
W1 N/A 2500 26.4.2.2(d)
W2 0.50 4000 26.4.2.2(d)
Maximum water-soluble chloride ion (Cl) content in concrete, percent by mass of cementitious materials[9,10] 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[11]
[1]The w/cm is based on all cementitious and supplementary cementitious materials in the concrete mixture.
[2]The maximum w/cm limits do not apply to lightweight concrete.
[3]For plain concrete, the maximum w/cm shall be 0.45 and the minimum fc' shall be 4500 psi.
[4]Alternative combinations of cementitious materials to those listed are permitted for all sulfate exposure classes when tested for sulfate resistance and meeting the criteria in 26.4.2.2(c).
[5]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.
[6]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.
[7]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).
[8]If Type V cement is used as the sole cementitious material, the optional sulfate resistance requirement of 0.040 percent maximum expansion in ASTM C150 shall be specified.
[9]The mass of supplementary cementitious materials used in determining the chloride content shall not exceed the mass of the portland cement.
[10]Criteria for determination of chloride content are in 26.4.2.2.
[11]Concrete cover shall be in accordance with 20.5.
Concrete subject to freezing-and-thawing Exposure Classes F1, F2, or F3 shall be air entrained. Except as permitted in 19.3.3.6, 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 6.0 7.5
1/2 5.5 7.0
3/4 5.0 6.0
1 4.5 6.0
1-1/2 4.5 5.5
2 4.0 5.0
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.
Wet-mix shotcrete subject to freezing-and-thawing Exposure Classes F1, F2, or F3 shall be air entrained. Dry-mix shotcrete subject to freezing-and-thawing Exposure Class F3 shall be air entrained. Except as permitted in 19.3.3.6, air content shall conform to Table 19.3.3.3.
Table 19.3.3.3—Total air content for shotcrete exposed to cycles of freezing and thawing
Mixture type Sampling location Target air content, percent
F1 F2 F3
Wet-mix shotcrete Before placement 5.0 6.0 6.0
Dry-mix shotcrete In-place N/A[1] N/A[1] 4.5
[1]Entrained air is not required in dry-mix shotcrete for these exposure classes.
Wet-mix shotcrete shall be sampled in accordance with ASTM C172, and air content shall be measured in accordance with ASTM C231 or ASTM C173.
Dry-mix shotcrete shall be sampled and air content shall be measured as directed by the licensed design professional.
For fc' ≥ 5000 psi, reduction of air content indicated in Table 19.3.3.1 and 19.3.3.3 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).
Nonprestressed concrete that will be cast against stay-in-place galvanized steel forms shall comply with the chloride ion limits for Exposure Class C1 unless a more stringent limit is required by other project conditions.
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 cementitious materials.
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