Minnesota Administrative Rules

1309.0402 SECTION R402, MATERIALS.

IRC Table R402.2 is amended to read as follows:

TABLE R402.2 MINIMUM SPECIFIED COMPRESSIVE STRENGTH OF CONCRETE

TYPE OR	MINIMUM SPECIFIED COMPRESSIVE STRENGTHa (f ʹc)
LOCATION OF	Weathering Potentialb
CONCRETE CONSTRUCTION
	Negligible	Moderate	Severe
Footingsg,h	5,000	5,000	5,000
Basement walls, foundations, and other concrete not exposed to the weather	2,500	2,500	2,500c
Basement slabs and interior slabs on grade, except garage floor slabs	2,500	2,500	2,500c
Basement walls, foundation walls, exterior walls, and other vertical concrete work exposed to the weather	2,500	3,000d	3,000d
Porches, carport slabs, and steps exposed to the weather, and garage floor slabs	2,500	3,000d, e, f	3,500d, e, f

For SI: 1 pound per square inch = 6.895 kPa.

^a Strength at 28 days psi.

^b See Table R301.2(1) for weathering potential.

^c Concrete in these locations that may be subject to freezing and thawing during construction shall be air-entrained concrete in accordance with footnote "d."

^d Concrete shall be air-entrained. Total air content (percent by volume of concrete) shall be not less than 5 percent or more than 7 percent.

^e See Section R402.2 for maximum cementitious materials content.

^f For garage floors with a steel-troweled finish, reduction of the total air content (percent by volume of concrete) to not less than 3 percent is permitted if the specified compressive strength of the concrete is increased to not less than 4,000 psi.

^g Compressive strength (f ʹ_c) of 2,500 psi, with an approved admixture that provides a water and vapor resistance at least equivalent to 5,000 psi concrete.

^h Compressive strength (f ʹ_c) of 5,000 psi is not required for post footings for decks or porches, wood foundations, slab-on-grade foundation walls, and footings for floating slabs.

Statutory Authority:

MS s 326B.02; 326B.101; 326B.106

History:

39 SR 91; 44 SR 764

Published Electronically:

March 31, 2020