decorative concrete considerations

Introduction:Decorative Concrete vs. “Normal” Concrete

Decorative Basics- TreatmentsColorTextureSealers & Joint Sealants

Bringing It all Together: Ensuring Success from Documentation to

Execution

The level of quality in any concrete project is directly proportional to the level of engagement… This is especially true where visual quality is of concern since we are primarily visual beings and it is the characteristic that is most readily recognized.

Aesthetics- it just looks better

Typically more attention to detail

Take advantage of easy (cheap) opportunities

Generally, an added cost

Traditionally, bigger scope = bigger risk

Lack of tools

Local RMC producers, supply houses, & vendors

Concrete Network online

CCAA Guide to Flatwork Finisheswww.concrete.net.au

ACI 303.1

PigmentsPowderLiquid

StainsHardeners

Topical Color

ASTM C979 Standard: Pigments for Integrally Colored Concrete

Color Chemical Formula Chemical Description Common Name

Black Fe3O4 Iron(II, III)oxide Iron Oxide BlackRed a-Fe2O3 Iron(III)oxide Iron Oxide Red Yellow a-FeOOH Iron(III)oxide hydroxide Iron Oxide YellowBrown Mixture of a-FeOOH Iron Oxide Brown

and/or Fe2O3 with Fe3O4

Green Cr2O3 Chrome(III)oxide Chrome Oxide Green

Blue CoAl2O4 Cobalt aluminate Cobalt BlueWhite TiO2 Titanium(IV)oxide Titanium Dioxide

Influence of the Cement Color on the Final Color Shade

Grey cement

White cement

Withoutpigment

Blue Yellow Green Red Brown Black

Bayferrox 920 Bayferrox 110 Bayferrox 318

2 %

0 1 2 3 4 5 6 7 8C

olo

ur

inte

nsi

tyPigment concentration [%]

based on cement

4 %

6 %

8 %

0 %

Bayferrox 318Bayferrox 110Bayferrox 920

Pigmentation Level Versus Final Color Shade

Influence of the Water-Cement (w/c) Ratio on the Color of the

Concrete

w/c 0.40

4 % Bayferrox 130

unpigmented

w/c 0.50w/c 0.45

Powder or Liquid

Dosage rate based on cement content

Added directly to transit mixer

Acid-based reagentsWater-based

reagents(not dyes)

Dry-shake

Hardners

Water-Based

Portland cementSilica sandPigment(s)

Trowel- finishBroom- finishStampsEmbedments/Rock

Salt

Surface RetardersAcid EtchBlast EtchSaw Cutting

Etching

HeavyLightSwirlWavyStraight

Broom

HeavyLightGenerally not

recommendedRequires slip-resistant

sealer

SkinsStampsRollers?

Acid EtchBlast EtchExposed Aggregate

“Traditional”Surface Retarders

Aggregates: Integral or Seededdepth of exposure should not be more than

40% of the coarse aggregate's diameterlight, medium, or deep exposures (and in-

between)w/c ratio can effect exposure depth

Width flares to ½”½” deep

1/8” wide1/16”-1/4” deep

Sawed

Brings out the colorResists StainingResists UV

DegradationPrevents Salt/Deicer/

Water Intrusion

Prevents Intrusion of Water & Incompressibles

Helps Reduce Pumping

Protects Against Joint Spalling & Deterioration

Joint Sealants

Acrylics are easiest to apply and dry quickly but require more maintenance. Both solvent and water based

Polyurethanes are thicker but moisture intolerant. Both solvent and water based.

Penetrating sealers (silanes, siloxanes, and silicates) provide great protection but produce matte finish.

Epoxies are generally not UV resistant and not suitable for exterior.

Cure & SealWater-basedSolvent-basedTinted sealersSlip- resistant grit

Ground polyethylene Silica sand

Many types availablePolyurethane or Polyurea

Great performaneEase of use

Backer RodClosed cell sealant backing: polyethylene foam w/

surface skinOpen cell sealant backing: urethane foam w/o a skin

Width-to depth ratio important-2:1 okay; 3:2 is better

Pavements with saw cuts and stabilized subgrades may not need sealant

Polyureathane

Ensure owner understands maintenance commitment

Maintain according to system manufacturerOtherwise follow ACI-330 guidelines

• Most stains will oxidize with time• Clean up wet oil and antifreeze with

absorbents prior to cleaning• Scrap dried and hard materials prior to

cleaning operations• Two main types of cleaning:

• Physical• Chemical

• Power Washing- may restore brightness to concrete but will not remove most stains

• Abrasive Blasting-Likely more expensive and will remove 1/16” of tops surface• Shot Blasting (will not remove heavy grease)• Sand Blasting

• Typically spot applied & scrubbed with stiff brush

• Rinsing the surface with water removes the cleaner and oil stains

• A variety of chemicals may be used (following manufacturers’ instructions):• sodium metasilicates• petroleum distillates• Trisodium phosphate (TSP)• sodium hydroxide (NaOH) solution mixed with

ground limestone

Reference ACI303.1Use proprietary spec if using a systemSpell out:

Who?What ?When?Where?Why?How?

Ensure bids cover what is spec’dUse a Design Reference StandardInsist on preconstruction meetingUtilize Field Mockup to mitigate

any issuesVisual field inspection is more

important that materials testingContractor Qualifications

ACI Flatwork FinisherPortfolio of previous work

Raise you expectations.

Specify product systems & certified finishers.

Insist on the best and do NOT accept shortcuts or substitutions (only proven equals).