Concrete inFocus - Spring 2017 - 21

Examples of ICF wall block configurations.
Images courtesy of Buildblock®.

flat-wall ICF systems dominate the marketplace. This can be attributed to the fact that
flat-wall ICF form units are designed to create standard reinforced concrete structural
elements, using well-documented design criteria, such as ACI-318.
There are at least a dozen companies that manufacture flat-wall ICF systems that can
deliver their product throughout the U.S. and Canada and many are members of the
Insulating Concrete Form Manufacturers Association (ICFMA). For more information,
visit www.icf-ma.org.
EPS insulation used for ICFs is governed by ASTM C 578, Type II closed cell foam with
an R-value of 4 per inch. Polystyrene beads are first expanded with steam forming high
density beads, which are injected into a mold to form the desired shape. Once removed
from the molds and cured, EPS is a stable and durable material ideal for construction. No
chlorofluorocarbons (CFCs), hydrofluorocarbons (HFCs) or formaldehydes are used in the
manufacturing process and there is no off-gassing. EPS is moisture resistant, non-absorbent
and resistant to mold and rot. EPS contains a flame retardant and the smoke from burning
is non-toxic. In addition, EPS is recyclable at its
end of life.
The key benefits of
ICF construction are:
The plastic ties that hold the two wythes of the
block together are generally made with polypro* Strength and durability
pylene plastic, but it does depend on the manufac* Fire safety
turer. They are designed to withstand the liquid
* Energy efficiency
concrete pressure during construction. Most
* Sustainability
manufacturers design their ties to secure hori* Noise reduction
zontal and vertical reinforcing bars into notches
* Long-term value
in the ties to minimize the need to use tie wire.
Although different manufacturers provide a wide range of spacing for ties, the most common spacing is 6 or 8 inches. The ties have no thermal bridging, they do not degrade or rot
over time, and all ties have furring strips embedded in the EPS for screw-on attachment of
exterior or interior finishes.
Reinforcing steel used in ICF walls is the same used for any other type of concrete structure. Typically, smaller diameter bars are used such as #4, #5 or # 6, but thicker bars can
be used for higher loading, concentrated loads and pilasters. In some cases, steel fibers have
been used in place of horizontal steel in ICF walls, but most common applications use both
horizontal and vertical steel reinforcement.
Concrete is typically placed in ICF walls using a boom-type concrete pump, though
line-pumps or even conveyor belt equipment can be used. Specified compressive strength
used in ICF walls can be whatever is required to resist structural loading, but most common
are a 3000 psi or 4000 psi concrete pump mix. The recommended maximum aggregate
size should be ½-inch aggregate for 4- and 6-inch cavity forms and ¾-inch aggregate for
8-inch and larger cavity forms. The required concrete slump is 6 inches, but could be up
to 8 inches or more to accommodate pumping using high-range plasticizers and mid-range
water reducing admixtures to achieve necessary flowability.
As construction continues, electrical and plumbing lines can be embedded into the interior
layer of foam by cutting channels with a hot knife or other tool. Interior or exterior finishes
can be applied directly to the surface by screwing into the plastic furring strips. Gypsum
wall board on the interior, and stucco, brick or siding on the exterior are common finishes
ideally suited to ICF construction but nearly any finish can be applied.

concrete INFOCUS

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21


http://www.icf-ma.org

Table of Contents for the Digital Edition of Concrete inFocus - Spring 2017

From the President’s Desk
Corporate Suite Column
Enviroscene Column
Strong and Efficient: Insulating Concrete Forms for Multifamily Residential Construction
Cut the Cost of Workers’ Compensation Insurance in the Concrete Industry
Engineering: Specifications for Concrete Construction
Predicting the Potential for Plastic Shrinkage Cracks
2017 Product Preview
Index of Advertisers
Concrete inFocus - Spring 2017 - belly1
Concrete inFocus - Spring 2017 - belly2
Concrete inFocus - Spring 2017 - cover1
Concrete inFocus - Spring 2017 - cover2
Concrete inFocus - Spring 2017 - 3
Concrete inFocus - Spring 2017 - 4
Concrete inFocus - Spring 2017 - 5
Concrete inFocus - Spring 2017 - 6
Concrete inFocus - Spring 2017 - 7
Concrete inFocus - Spring 2017 - 8
Concrete inFocus - Spring 2017 - 9
Concrete inFocus - Spring 2017 - 10
Concrete inFocus - Spring 2017 - From the President’s Desk
Concrete inFocus - Spring 2017 - 12
Concrete inFocus - Spring 2017 - Corporate Suite Column
Concrete inFocus - Spring 2017 - 14
Concrete inFocus - Spring 2017 - 15
Concrete inFocus - Spring 2017 - Enviroscene Column
Concrete inFocus - Spring 2017 - 17
Concrete inFocus - Spring 2017 - Strong and Efficient: Insulating Concrete Forms for Multifamily Residential Construction
Concrete inFocus - Spring 2017 - 19
Concrete inFocus - Spring 2017 - 20
Concrete inFocus - Spring 2017 - 21
Concrete inFocus - Spring 2017 - 22
Concrete inFocus - Spring 2017 - 23
Concrete inFocus - Spring 2017 - 24
Concrete inFocus - Spring 2017 - 25
Concrete inFocus - Spring 2017 - 26
Concrete inFocus - Spring 2017 - 27
Concrete inFocus - Spring 2017 - 28
Concrete inFocus - Spring 2017 - 29
Concrete inFocus - Spring 2017 - 30
Concrete inFocus - Spring 2017 - Cut the Cost of Workers’ Compensation Insurance in the Concrete Industry
Concrete inFocus - Spring 2017 - 32
Concrete inFocus - Spring 2017 - 33
Concrete inFocus - Spring 2017 - 34
Concrete inFocus - Spring 2017 - 35
Concrete inFocus - Spring 2017 - 36
Concrete inFocus - Spring 2017 - Engineering: Specifications for Concrete Construction
Concrete inFocus - Spring 2017 - 38
Concrete inFocus - Spring 2017 - 39
Concrete inFocus - Spring 2017 - 40
Concrete inFocus - Spring 2017 - Predicting the Potential for Plastic Shrinkage Cracks
Concrete inFocus - Spring 2017 - 42
Concrete inFocus - Spring 2017 - 43
Concrete inFocus - Spring 2017 - 44
Concrete inFocus - Spring 2017 - 45
Concrete inFocus - Spring 2017 - 2017 Product Preview
Concrete inFocus - Spring 2017 - 47
Concrete inFocus - Spring 2017 - 48
Concrete inFocus - Spring 2017 - 49
Concrete inFocus - Spring 2017 - 50
Concrete inFocus - Spring 2017 - 51
Concrete inFocus - Spring 2017 - 52
Concrete inFocus - Spring 2017 - 53
Concrete inFocus - Spring 2017 - Index of Advertisers
Concrete inFocus - Spring 2017 - cover3
Concrete inFocus - Spring 2017 - cover4
Concrete inFocus - Spring 2017 - divider1
Concrete inFocus - Spring 2017 - divider2
Concrete inFocus - Spring 2017 - 57
Concrete inFocus - Spring 2017 - 58
Concrete inFocus - Spring 2017 - 59
Concrete inFocus - Spring 2017 - 60
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