Code of Massachusetts Regulations
780 CMR - STATE BOARD OF BUILDING REGULATIONS AND STANDARDS
Chapter 19 - Concrete
Section 1904 - DURABILITY REQUIREMENTS
Subsection 1904.3 - Concrete properties

Universal Citation: 780 CMR MA Code of Regs 1904.3
Current through Register 1531, September 27, 2024

Concrete mixtures shall conform to the most restrictive maximum water-cementitious materials ratios and minimum specified concrete compressive strength requirements of ACI 318, Section 4.3, based on the exposure classes assigned in Section 1904.2.

Exception: For occupancies and appurtenances thereto in Group R occupancies that are in buildings less than four stories above grade plane, normal-weight aggregate concrete is permitted to comply with the requirements of Table 1904.3 based on the weathering classification (freezing and thawing) determined from Figure 1904.3 in lieu of the requirements of ACI 318, Table 4.3.1.

TABLE 1904.3 MINIMUM SPECIFIED COMPRESSIVE STRENGTH (f 'c)

TYPE OR LOCATION OF CONCRETE CONSTRUCTION MINIMUM SPECIFIED COMPRESSIVE STRENGTH (f 'c at 28 days, psi)
Negligible exposure Moderate exposure Severe exposure
Basement wallsc and foundations not exposed to the weather 2,500 2,500 2,500a
Basement slabs and interior slabs on grade, except garage floor slabs 2,500 2,500 2,500a
Basement wallsc, foundation walls, exterior walls and other vertical concrete surfaces exposed to the weather 2,500 3,000b 3,000b
Driveways, curbs, walks, patios, porches, carport slabs, steps and other flatwork exposed to the weather, and garage floor slabs 2,500 3,000b, d 3,500b, d

For SI: 1 pound per square inch = 0.00689 MPa.
a. Concrete in these locations that can be subjected to freezing and thawing during construction shall be of air-entrained concrete in accordance with Section 1904.2.1.
b. Concrete shall be air entrained in accordance with Section 1904.4.1.

c. Structural plain concrete basement walls are exempt from the requirements for exposure conditions of Section 1904.3 (see Section 1909.6.1).
d. For garage floor slabs where a steel trowel finish is used, the total air content required by Section 1904.4.1 is permitted to be reduced to not less than 3 percent, provided the minimum specified compressive strength of the concrete is increased to 4,000 psi.

a. Lines defining areas are approximate only. Local areas can be more or less severe than indicated by the region classification.
b. A "severe" classification is where weather conditions encourage or require the use of deicing chemicals or where there is potential for a continuous presence of moisture during frequent cycles of freezing and thawing. A "moderate" classification is where weather conditions occasionally expose concrete in the presence of moisture to freezing and thawing, but where deicing chemicals are not generally used. A "negligible" classification is where weather conditions rarely expose concrete in the presence of moisture to freezing and thawing.
c. Alaska and Hawaii are classified as severe and negligible, respectively.

FIGURE 1904.3 WEATHERING PROBABILITY MAP FOR CONCRETEa, b, c

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