Owner`s manual

A. Concrete Curb Mix:

1) Components of One(1) Cubic Yard of Concrete Curb Mix:

a) Cement:

Use Portland Cement. Typically, Concrete Curb Mixes use 6 to 7 sacks/564-660# of

Portland Cement per cubic yard. A higher concentration of cement is required

because of the greater surface area of the smaller aggregates used in this mix. When

desired, certain Mineral Admixtures can be substituted for some but not all of the

Cement in the mix. These Admixtures include Fly Ash or Ground Granulated Blast

Furnace Slag (GGBF Slag). Consult the job specifications and your local concrete

plant to determine what allowances are possible for these Admixtures.

b) Water:

Water used in the mix must be clean and clear. Potable/Drinkable water is best

but not required. Between 25 to 40 gallons of water per cubic yard will produce 1-2”

slump depending on the moisture content already in the aggregate. Let the concrete

plant know what slump you need when the Mix is DELIVERED to the job site. They

will make allowances for the moisture content in the aggregates and travel time.

c) Aggregates: Crushed aggregates produce stronger Curb Mixes and have better

standing properties when extruding taller curbs than smooth river stone. A good

starting point is an aggregate blend having 60% sand and 40% stone.

Sand: Use Concrete sand blend with 100% passing a #8/2.4 mm Sieve.

Stone: Use Stone with 100% passing a 3/8”/9.5 mm sieve. When extruding curb

forms with 8” or 10” augers some of the 3/8” stone can be replaced with larger stone

up to ¾”/#57. If excessive voids appear in the Mix, reduce the size of the larger stone

(not the %) until the curb surface improves.

d) Admixtures:

Note: Consult the job site specifications to determine requirements/allowances

for admixtures.

1) Air Entraining Admixtures: Adds durability to Concrete Curb exposed to cold

weather and road salt.

2) Retarding Admixture: Slows down the early hardening of concrete. Extends

workability/finishing time.

3) Water Reducing Admixture: Reduces the amount of water and cement required to

achieve a given slump in the concrete. The use of this admixture can increase the

strength of the concrete.

2) A recommended mix design for one cubic yard of concrete:

Cement: 660# (7 sacks)

Sand: 1,600 #, 5% moisture

Aggregate: 1,400 #, 3/8"

Water: Approximately 25 gallons/ 1” Slump