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

Current through Register 1525, July 5, 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.
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							 image
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