1 Concrete Masonry Weights and Process • Two basic weights – Normal weight 40 lbs. / unit 1,200-1,800psi comp strength – Lightweight 22-28 lbs. / unit 700 - 1,000 psi comp strength • Molded with a very dry mix - 3 to a mold – Molds cost over $25,000 each – Mold is cycled 3 to 5 times per minute – Cured in low pressure steam kiln to give rapid strength - 90% of rated strength in 2-4 days. – Remains very porous unless formulated for face units – Expands when wet - contracts when dry Grades & Types • Grades – “N” for exterior or moisture exposure below grade – “S” for no weather or moisture exposure • Types – I Moisture controlled (N-I or S-I) conforms to ASTM standards for moisture in concrete block. – II Unrestricted moisture content - may shrink excessively - don’t use with brick!
Transcript
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Concrete Masonry
Weights and Process• Two basic weights
– Normal weight 40 lbs. / unit 1,200-1,800psi compstrength
• Molded with a very dry mix - 3 to a mold– Molds cost over $25,000 each– Mold is cycled 3 to 5 times per minute– Cured in low pressure steam kiln to give rapid strength -
90% of rated strength in 2-4 days.– Remains very porous unless formulated for face units– Expands when wet - contracts when dry
Grades & Types
• Grades– “N” for exterior or moisture exposure below grade
– “S” for no weather or moisture exposure
• Types– I Moisture controlled (N-I or S-I) conforms to ASTM
standards for moisture in concrete block.– II Unrestricted moisture content - may shrink excessively -
don’t use with brick!
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PartsFace shell
Face shell
WebsFlanges
Apply mortar here
8” tocenterofmortarjoint
7 5/8”Blockheightdimension
Standard sizes work with modular brick
Block Sizes
• Concrete MasonryUnits (CMU’s) arenominally consideredto be 16 inches long,8 inches tall and 2 to12 inches deep.
• A CMU’s actualdimension is always3/8” less than thenominal, to makeroom for a mortarjoint.
15 5/8”
1 5/8”3 5/8”
5 5/8”
7 5/8”
9 5/8”
11 5/8”
2” block
Nominaldimension
Actualdimension
4” block
6” block
8” block
10” block
12” block
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Block form typesStandard block for running bond
Solid end for corner blocks
Solid block
Bullnosed block for soft corners
Return block for corners in 10 or 12inch block walls
10” or 12”16”
10” or 12”
Block surface types• Standard - appears just as it is when withdrawn from the
autoclave
Block surface types…split face
Split face - two blocks poured face to face, then splitbefore curing to make rough textured irregular face
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Ground face - face ground lightly to polish cement particlesand expose color of aggregate in the concrete
Block surface types…ground face
Colored - mineral colorants added to theconcrete mix, more like a deep tint than asolid color.
Block surfacetypes…colorants
Scored face - sawcut to same dimension asmasonry joint to simulate smaller block face, canbe single score to give 8x8 square pattern on face,double score, or triple score.
Single scored split face
Block surface types…scored
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Block surface types...Spectra-glaze
• Glazed face - ceramic adhered toface in autoclave process, deeplysaturated bright color possible,permanent color, permanent bond
• Www.spectraglaze.com
Fluted, block are formed or sawcut tomake a vertical flute pattern.
Block surface types…fluted
Split faced fluted
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Smooth (standard face) block
Split face block
Saxon sized brick
Maximum heights / lengths ofwall
• Rule of Thumb:– Load bearing: Unbraced height or length for a 2 wythe wall
(backup + veneer) = 18 x total thickness (backup + veneer)– Non loadbearing:
