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Concrete SlabQuality Requirements
Who Controls Concrete Quality• Polishing contractors have to perform
work on a concrete floor slab in which they had no control over design and placement quality
• Design professionals have to be proactive and see that certain requirements are included in concrete specification
Pre-Concreting Meeting
Polishing contractor should participate in the meeting
Flat Subgrade• Should be
uniformly graded flat and level
• Subgrade rises and depressions can cause variations in concrete slab thickness thus causing color differences because of differential curing and drying
Vapor Retarder• Product should comply with ASTM E 745
and have permeance of 0.01 perms after conditioning according to ASTM E 154 Section 7.1
• Installation should comply with ASTM E 1643
Concrete Mix Design• Consistent source for materials• W/C of 0.45• 3,500 psi• Normal weight aggregates• Not air-entrained• No replacements for portland
cement
Construction Joints and Patches• Strategically locate
construction joints to avoid mismatching segments
• Patch finish will not match surrounding surfaces
Steel Column BaseplatesBe aware of design of concrete at steel column baseplates
Placing• Comply with ACI standards• End of chute or tremie not
more than 6 ft above point of placement
• Monitor and control:- Concrete temperature- Water added at site
Flatness and LevelnessSpecified Overall
ValueMinimum Local
Value
FF Floor Flatness 50 35
FL Floor Levelness 30 20
Finishing• Specific procedures recommended• Steel trowel surface in three passes
without burning surface• Do not dust surface
with dry portland cement or sand to accelerate curing and drying
Curing and Drying• Evaporation control • Wet-curing method
EnvironmentalBenefits
Environmental Benefits• Polished concrete does
not have to be removed or replaced; it can be “forever”
• Light reflective• Durable• Flooring covering products not needed• Low maintenance requirements
