Technical Information for ProBlock Masonry Units ASTM C-90 Compliance Concrete masonry units (CMU) had not changed much since 1931 with the original publication of ASTM C90, Standard Specification for Hollow Loadbearing Concrete Masonry Units, until 2011, with ASTM C90 2011b, which allows for, but does not require, a unit’s webs to be configured differently. As a result, CMU designs may be altered in order to utilize fewer raw materials in production, reduce unit weight and/or increase energy efficiency of concrete masonry construction. ASTM C90 changed from requiring a minimum web thickness to requiring a minimum web area of 6.5 square inches per square foot of face area. No longer are manufacturers required to have three 1” thick webs on 8” block; instead an 8x8x16 block could have one web as thin as 0.75” and still meet ASTM C90’s new minimum web area requirements. Johnson Concrete’s ProBlock utilizes thinner webs and has an open end to increase energy performance and improve mason productivity and safety. The web area of the 8 and 12 inch ProBlock Energy Max is about 13.8 in 2 /ft 2 which meets the new C90 requirements. ProBlock comes in an Energy Max version which has higher thermal efficiency and slightly reduced weight compared to the 2 hour ProBlock version. The 8 inch 2 hour ProBlock has an equivalent thickness of about 3.7 inches and is produced using only ESCS lightweight aggregates. The unit configuration and density meets the 2 hour fire rating requirements of both the International Building Code and North Carolina Building Code. ProBlock meets ASTM 90 requirements for compressive strength when tested as a whole unit or when tested as a closed cell unit per ASTM C140. The compressive strength of ProBlock is the same as with the standard lightweight unit produced by Johnson Concrete. Johnson Concrete is happy to provide project specific R value calculation based on actual grout spacing, grout material selection and ProBlock selected. Johnson Concrete can also assist in determination of STC, heat capacity, net and average section properties, fire rating and grout estimation for projects using the ProBlock. The following sections offer more detail about some of the features of the ProBlock.
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Technical Information for ProBlock Submittal · 2020. 10. 28. · Technical Information for ProBlock Masonry Units. ASTM C-90 Compliance Concrete masonry units (CMU) had not changed
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Technical Information for
ProBlock Masonry Units ASTM C-90 Compliance
Concrete masonry units (CMU) had not changed much since
1931 with the original publication of ASTM C90, Standard
Specification for Hollow Loadbearing Concrete Masonry
Units, until 2011, with ASTM C90 2011b, which allows for,
but does not require, a unit’s webs to be configured
differently. As a result, CMU designs may be altered in order
to utilize fewer raw materials in production, reduce unit
weight and/or increase energy efficiency of concrete
masonry construction. ASTM C90 changed from requiring a
minimum web thickness to requiring a minimum web area of
6.5 square inches per square foot of face area. No longer are
manufacturers required to have three 1” thick webs on 8”
block; instead an 8x8x16 block could have one web as thin as
0.75” and still meet ASTM C90’s new minimum web area
requirements. Johnson Concrete’s ProBlock utilizes thinner webs and has an open end to
increase energy performance and improve mason productivity and safety. The web area of the
8 and 12 inch ProBlock Energy Max is about 13.8 in2/ft2 which meets the new C90
requirements.
ProBlock comes in an Energy Max version which has higher thermal efficiency and slightly
reduced weight compared to the 2 hour ProBlock version. The 8 inch 2 hour ProBlock has an
equivalent thickness of about 3.7 inches and is produced using only ESCS lightweight
aggregates. The unit configuration and density meets the 2 hour fire rating requirements of
both the International Building Code and North Carolina Building Code. ProBlock meets ASTM
90 requirements for compressive strength when tested as a whole unit or when tested as a
closed cell unit per ASTM C140. The compressive strength of ProBlock is the same as with the
standard lightweight unit produced by Johnson Concrete.
Johnson Concrete is happy to provide project specific R value calculation based on actual grout
spacing, grout material selection and ProBlock selected. Johnson Concrete can also assist in
determination of STC, heat capacity, net and average section properties, fire rating and grout
estimation for projects using the ProBlock. The following sections offer more detail about
some of the features of the ProBlock.
ProBlock Insulated Wall System: Energy Performance
R-value is the measure of thermal resistance used in the building and
construction industries. Higher R-value equates to increased
resistance to heat flow. R-value measures the ratio of the
temperature difference across an insulator (concrete masonry wall)
and the heat flux (heat transfer per unit area per unit time). The key
to maximizing whole-wall R-values of concrete masonry walls is
minimizing thermal bridges within the concrete masonry units, and
increasing the thermal resistance of the concrete used to produce
concrete masonry units. Lightweight concrete is ideal for highest thermal performance concrete
masonry wall assemblies.
Whole-wall R-values for ProBlock walls are much greater than
conventional 3-web concrete block walls. The increase achieved by
injecting aminoplast foam insulation is up to 264% greater than what is
possible with normal weight concrete masonry walls injected with the
same aminoplast foam injection. The table below illustrates the
exceptional thermal performances that can be achieved by specifying