GUIDELINES FOR DURABLE CONCRETE
[ UNDERSTANDING CONCRETE ]
Terms:
Concrete May Also Have In It:
[ MIX DESIGN ]
Too Much Cement:
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Increases the cost of the concrete.
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Will produce concrete that is less resistant to abrasion.
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Will produce concrete that cracks more easily.
Too Much Aggregate:
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Makes the mix stiff or harsh. Difficult to place and finish.
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Too much sand requires excessive water which may lead to cracking and excessive shrinkage.
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Will produce concrete that cracks more easily.
[ SPECIFICATIONS ]
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Typically a 4000psi mix should be used for concrete that is subject to freeze thaw conditions. Work with your producer to find the mix that is right for your job.
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Contractor and ready mix producers should discuss the savings and advantages of the "Value Added" mixes such as those for freeze resistance.
[ PLANNING ]
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Thickness: 4" is generally enough unless heavy trucks will park regularly.
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Base: Firm subsoil is generally adequate. Sand or stone base assists in providing uniformity and drainage.
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Reinforcement: Wire mesh is not necessary, unless specified. Nylon fibers can also be used.
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Drainage: Always slope for positive drainage. Min: 1/8" drop per foot.
SEE: PREPARATION
[ FILLING THE FORMS ]
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Chute, wheel, or shovel concrete directly into its final position.
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Do not use rakes to distribute concrete because it will cause segregation of components.
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Do not drop the concrete more than 4' from its final location to prevent aggregate segregation.
[ LEVELING ]
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Screed (strike off) twice to level the surface.
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Immediately use wood or mag bullfloat to take out small high and low spots.
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Then, stop everything on that portion of the slab until bleed water (water sheen) disappears from surface.
SEE: FINISHING
SEE: CURING
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