Your Guide to Using Bayferrox® Pigments to Color Concrete Products

LANXESS Corporation was formed whenthe Bayer Group combined most of its chem-icals businesses with large segments of itspolymers activities. The company begandoing business as a new legal entity in theUnited States on July 1, 2004. LANXESSwill continue manufacturing Bayferrox® ironoxide pigments, which is a registered trade-mark of Bayer AG, Germany.

The use of color in concrete building materials is increasing in popularity.Today, it is an important designtool for architects, builders, engineers andhomeowners to express their style andindividuality. Color is commonly used inproducts such as concrete roofing tiles,pavers, block, precast products, andsegmental retaining wall units. These coloredbuilding materials are in high demand andare also more profitable to manufacturersthan their uncolored counterparts.

As a result, manufacturers of concretebuilding materials are faced with thechallenges of selecting and using pigmentscorrectly in their production facility. AtLANXESS Corporation, we understandthese challenges and are here to assist you.That is why we have produced this detailedbrochure. It is your guide to understanding

and using Bayferrox pigments in concreteproducts. It summarizes the experiences, lab-oratory tests, and in-plant trials thatLANXESS Corporation and our parentcompany, LANXESS Deutschland Gmbh,located in Germany, have accumulatedworldwide over the past several decades.

Raw Materials That Affect Color in ColoredConcrete ProductsPigmentYour choice in pigment is the first, mostimportant decision you make in producingquality colored concrete products. Years of tests on colored products exposed todifferent climate conditions all over theworld have shown that our Bayferrox syn-thetic iron oxide pigments have superiorperformance properties in cementitiousproducts.

Demands Made on PigmentsPigments for concrete products are requiredby ASTM C979 to withstand aggressiveinfluences of strong, alkaline cement paste.They must also be lightfast, weather-stable, and insoluble in water. During processing, the pigment must becomefirmly integrated into the concrete matrix.Inorganic pigments, especially iron oxides,do this particularly well. ASTM limits theamount of pigment added to concrete to 10percent by weight of the amount of cemen-titious materials in the mix. All Bayferroxpigments meet ASTM C979 requirements.

ISO CertificationBayferrox from LANXESS has ISOcertification, which is your assurance thatall steps in the manufacturing of Bayferroxhave been detailed.

The Bayferrox manufacturing unit in New Martinsville, West Virginia.

1

The ISO series of standards was developedby the International Organization forStandardization (ISO) to satisfy theincreasing demands of quality-consciouscustomers. At LANXESS, we are extremelyproud that our meticulous detail in manu-facturing Bayferrox iron oxide pigmentshas been recognized with ISO certification.

Most Important Shades

From these primary pigments, the mostcommonly used colors in building materialscan be made. By changing the pigmentshade, the amount of color added, or thecolor of the cement and other raw materials,an almost infinite variety of final colors ispossible, for example: Red pigment Light pink to dark purple

Yellow pigment Pale yellow to mustard

Brown pigment From light buff to dark brown

Black pigment Pale gray to dark charcoal

Green shades can also be produced.

CementAll concrete products contain cement, andthe color of the cement affects the final colorof the product tremendously. The cementacts as a binder between the sand, aggre-gates, and pigment in the concrete, holdingeverything together. It is the cement, and thepaste that is created when water is added,that incorporates and binds the pigmentparticles in the product and prevents themfrom being washed away.

The most common color of cement is gray.And since the color gray detracts from thebrilliance of any color whenever it is used,it is impossible to obtain many bright or

300

100�

800 or 900

600 or 6000

GN or GX

TRADE NAME GENERIC NAME SHADE NUMBERS

Iron oxide black

Iron oxide red

Iron oxide yellow

Iron oxide brown

Chrome oxide green

Bayferrox Black*

Bayferrox Red*

Bayferrox Yellow*

Bayferrox Brown

Chrome Oxide Green*

*Available as powders and granules

pastel colors using gray cement. Gray cementworks best with darker colors such as darkbrowns, blacks, grays, and many reds.

Whenever pastel shades are desired, amanufacturer must use white cement. Lightor bright shades of pink, tan, blue, green, andyellow are possible with white cement. Withchrome oxide green or cobalt blue pigments,the color difference using white instead ofgray cement is pronounced. When whiteaggregates are used with white cement andpigments, even brighter shades are possible.

Cement companies make many types ofcement, and they vary in color from lightto dark shades of gray. And as is the casein comparing dry pigment powders, it is notpossible to tell final color of concrete bylooking at the color of the cement powder.Therefore, to reduce the risk of colorinconsistency on the same project, use thesame cement supplier and cement type.Whenever changing suppliers, or type ofcement, it is important to understand thatfinal color will likely change.

In coloring concrete, the pigment particlesare insoluble and 10 times finer than cement.Since cement is the “glue” that holds theconcrete product together, it also holds thepigment in place. And since the amount of pigment added to a concrete mix isdetermined (in percentages) by the totalweight of the cementitious materials, as theamount of cement changes so does theamount of pigment and the final color of aconcrete product. If the amount of pigmentin pounds added were constant, but theamount of cement varied, the one withhigher cement content will have a lesssaturated color.

Influence of the cement color on the color of the concrete

Whitecement

Graycement

4% Bayferrox 820

4% Bayferrox 110

4% Bayferrox 330

2Note: Because of variables in photography and printing, the actual color of the concrete products shown maydiffer from the colors as they appear in the brochure.

‡

‡

‡

‡

WaterWhen attempting to produce uniform colorshades of pigmented concrete, it is importantto carefully monitor the amount of mixingwater added to the mix, and the moisturecontent of the raw materials, particularly thesand. Not only does a high water-cementratio have a detrimental effect on the strengthof the concrete, it also makes the productappear a lighter color.

Why is this true? Think about a freshlypoured glass of beer. The top of that glassis white foam, while the rest of the glass is filled with beer that is a golden, ambercolor. That’s because the foam consists of many tiny air bubbles that scatter lightmaking it a very light, bright color.Similarly, in a concrete product, excessmixing water evaporates to the surface and leaves behind many fine pores or cavities – like foam in beer – that makethe concrete appear lighter in color.Therefore, the higher the water-cementratio, the lighter the concrete appears. And this lighter color is true whether ornot the concrete has been pigmented.

Consequently, all producers of concreteproducts must carefully monitor theamount of mixing water and the moisturecontent of the aggregates to ensure a consistent color in their products.

Brilliant, glossy shades, like those of paintsor plastics, cannot be attained in concreteproducts because of the composition andinherent nature of concrete. Further, thesmooth surfaces of paints and plasticsreflect light differently than concrete,contributing to their brighter appearance.

AggregatesIn addition to cement, all concrete productscontain sand and aggregates, and their colorhas an effect on the final color of a productsince they represent the biggest part of theconcrete mix. These aggregates will even-tually be exposed after extensive weathering.

Concrete products can be “washed” or“ground” during manufacturing to removethe colored cement paste, exposing theaggregate color immediately. In eitherinstance, just as with cement color, thenatural color of the aggregates has a moremarked effect on concrete that’s been coloredwith a low dosage of pigment than onhigher pigment concentrations.

The extent to which color is affected bysand and aggregate depends on the mixdesign. If the cement to aggregate ratio is1:10 or higher, more of these particles willbe exposed on the surface of the concreteand not coated by the colored cement paste.Consequently, in these formulas, the colorof these raw materials – and any variationto them – will show up more.

Influence of the color of the aggregates onthe color of the concrete

Pale aggregates

Darkaggregates

4% Bayferrox 820

4% Bayferrox 110

4% Bayferrox 330

Influence of the water-cement (w/c) ratio on the color of the concrete

w/c 0.30 w/c 0.35 w/c 0.40

Un-pigmented

2%Bayferrox 130

4%Bayferrox 130

Influence of the cement content on the color of the concrete

556lb/yd3

758lb/yd3

4% Bayferrox 820

4% Bayferrox 110

4% Bayferrox 330

3

Pigments in DetailAvailable Pigment FormsFor decades, pigment powder was the onlyform of pigment available. Worldwide,powder is the most commonly used formof pigment because it is available in a widerange of colors, and economic advantagesmake powder appealing. Powder, however,is dusty and does not flow freely. Whentrying to meter powder to the mixer auto-matically, there are few systems available.

Today, the concrete product manufacturershave other choices. Pigment can also bepurchased as a pre-manufactured slurry.When slurries were first introduced, theyprovided the manufacturer with a free-flowing, non-dusting product that could bemetered automatically. However, freight(shipping water is expensive), availability,cost of coloration, settling, freezing andevaporation problems limit their use.

The latest pigment form makes it possibleto meter the pigment pneumatically andvery accurately to the mixer in its dry state.At first there were granules made in a spraydryer: many particles of powder combinedinto pigment “spheres.” Then in 1997,our parent company introduced a patentedsecond generation of these pigments, calledBayferrox C. The “C” is for “compacted”or many particles of standard Bayferroxpowders pressed together. Bayferrox C is a free-flowing, low-dusting, and irregularlyshaped granule, that is suitable for cemen-titious applications.

There is not an easy answer to the question,“What type of pigment is best for me?”There are advantages and disadvantages toeach. Talk to your Bayferrox representativeabout the form that best suits your currentand future needs.

Tinting StrengthWhenever pigment is used in concrete, itmust be added by weight. That weight isdetermined as a percentage of the weightof the cementitious materials in the mix,typically 3 or 4%. Throughout this brochure,you will notice various percentages ofpigment used.

Not all pigments are alike. In their dry state,like colors may appear to be identical, butsince pigment is never used without mixingit into something, like concrete, you shouldnever evaluate pigment by itself. Once pig-ment is mixed into the concrete and the prod-uct is allowed to cure, significant color differ-ences between two pigments that appearedsimilar in their dry state will be visible. Thiscolor difference demonstrates the tintingstrength – and the color – of the two pigments.

For example, in the picture above, the twored powders look nearly identical. On theleft is clay brick dust and on the right is astandard Bayferrox red pigment. But oncethese “pigments” are mixed in concreteat 6% pigment loading, the resultingcolor difference is significant.

In the next example, comparing Pigment “A”to Pigment “B” at 3% pigment loading, threedifferent pavers were made. Notice the twopavers using Pigment A, one at 3% loadingand the other at 10%. Now compare thosepavers to the one made with 3% Pigment B.

At 3% loading of both pigments, the colorslook totally different. But when 10% ofPigment A is used, it looks similar in colorusing only 3% of Pigment B. Therefore,Pigment B is significantly higher (3x) intinting strength than A. Although A may beless expensive to buy per pound, it may notbe the most economical pigment to use.

4

Comparison between a pigment with low tinting strength and

a pigment with high tinting strength

Pigment “A” Pigment “B”

3%

10%

3%

Pigment Loading

The chart above demonstrates that as morecolor is added to concrete, the color changes.On the graph, the color intensity was plottedin terms of reflectance readings as a functionof pigment addition. The photos demonstrateactual color change, and you can see thatchange is significant from 2% up to 6%when using pure synthetic iron oxide pigments. Within the 5 to 6% range,Bayferrox pigments reach their optimum saturation level.

As more Bayferrox is added, there is littledifference in the pavers colored from the 6to 8% loadings. This is demonstrated in boththe sample paver colors, and on the graphshowing the leveling of the reflectancecurve. Therefore, not only is it unnecessaryto add this much material, it also becomesuneconomical. It is important to know theoptimum pigment loading to achieve thedesired color so that only the exact amountof pigment necessary is added to the mix.

ColorfastnessColorfastness is the measurement of howfade resistant a pigment is when exposed tothe elements over a period of time. Our parentcompany has conducted extensive tests onpigments used in concrete applications.Shown below is our own weathering stationat our headquarters where concrete roofingtiles and other concrete products are evaluatedfor their colorfastness. Years of experiencehave proven that only outdoor weatheringtests provide reliable conclusions about theweather stability of pigments in concrete.Accelerated weathering tests, conducted withlaboratory equipment, do not provideaccurate durability data, especially regardingcarbon black and select organic pigments.

When pure synthetic or natural iron oxidepigments are used to color concrete products,the pigments don’t fade. Rather, as theconcrete product is exposed to the elements,the surface of the product erodes. Thisnatural erosion changes the surface of theproduct: cement and pigment particles aregradually removed, more aggregate particlesare exposed, dirt gets ground into the surface,etc. All these actions have a deleteriouseffect on the color of the product, but thepigment has not faded.

0 1 2 3 4 5 6 7 8Pigment concentration [%]

Bayferrox 330Bayferrox 110Bayferrox 820

Influence of the pigment concentration onthe color of the concrete

Bayferrox 820 Bayferrox 110 Bayferrox 330

2%

4%

6%

8%

Exposed and unexposed sample panels5

The sample wall panel of concrete brickon the previous page shows that colorchange after 25 years of exposure is verylittle compared to the unexposed samplesin front of them, apart from a slight soilingof the surface. As discussed earlier, this isnot color fading. Rather, the surface haseroded slightly and the cement matrix (andpigment particles) have been removed.

Carbon BlackIn addition to our own tests, Germany’sFederal Institute for Material Research andTesting (BAM) conducted tests of concretesamples colored with carbon black,Bayferrox iron oxide black pigments, andvarious blends using Bayferrox red (TestReport No. 2.1/21219/5). The results of thesetests show that samples pigmented withcarbon black fade significantly on exposureto weathering, while only a very slightchange in shade is observed in those samplespigmented with Bayferrox black. In prod-ucts colored with a blend of Bayferrox pig-ments versus those that used carbon blackin the blend, those with carbon blackturned red after exposure while those thatused the blend of the Bayferrox pigmentsretained their orginal dark brown color. Notonly does this prove that carbon blackfades, but that red iron oxide pigmentsused in the brown blend are colorfast.

Organic PigmentsOrganic pigments are an excellent choicefor automotive, industrial and architecturalpaints, but most organic pigments do notmeet ASTM C979 for coloring concreteproducts. They are incapable of withstand-ing the highly alkaline environment ofcementitious products. In outdoor weather-ing tests, concrete products colored with amajority of organic pigments available fadein only a few months.

Pigment Quantity Affects Color DurabilityRemember that cement is the “glue” thatholds the concrete product together, that itholds the insoluble pigment particles inplace, and that the amount of pigment addedto a concrete mix is determined by weightas a percentage of the weight of the cement.As pigment addition increases or decreases,the amount of pigment particles changesproportionally.

On the surface of concrete, there is a layerconsisting of the aggregate fines, cementpaste, and pigment particles being held inplace. The thickness of this layer dependson the mix design, method of compaction,etc. As this layer is exposed to weather andits effects, the fine particles of the cementmatrix are gradually worn away, taking awaythe pigment, while the aggregate particlesin the surface become exposed, resulting inthe aggregate color contributing more tothe overall color of the product.

Consequently, at low pigment loadings, thereare fewer pigment particles for the cementto hold into place. Therefore, a color changeover time is more visible at low loadingsthan at a higher pigment loading whereyou would have more pigment particlesbeing held into place.

Weather stability of black pigments:concrete pavers after 24 months

in a marine climate

Bayferrox 318 Carbon BlackBayferrox 320 +Bayferrox 110

Carbon Black +Bayferrox 110

A

B

A: Unweathered B: Weathered

6

The Production ofColored ConcreteProductsMetering PigmentsOnce the form of pigment has been deter-mined, the equipment to meter the pigmentmust be selected. This can be a daunting taskwith the numerous choices available, butLANXESS is here to help you. Althoughwe are not in the pigment metering equipment business, we work closely with the manufacturers of various systems. Our representatives are available to assist you inselecting an approved system to meet yourneeds. Here are some of the more impor-tant issues to consider when selecting anautomatic pigment metering system:• Cost of equipment• Metering accuracy• Space requirements• Number of formulas• Batch cycle time• Number of mixers

Measuring PigmentsDry pigment powders and Bayferrox C mustbe measured by weight. In most practicalcases, an accuracy of +/- 5% per color issufficient to avoid noticeable color fluctua-tions. Under no circumstances should drypigment be added by volume. First of all,pigments have a different volume to weightratio. Also, the bulk density of a particulargrade may vary from shipment to shipmentbecause of different compactions on thepallet, or storage conditions. Therefore, usinga coffee can for “weighing” pigment byvolume may result in batch to batch colorinconsistencies. Pigment slurries can bemeasured either by weight or volume.

Bayferrox pigments are manufactured inthree basic colors: red, yellow and black.Though various shades of these primarycolors are available, selecting one standardblack and yellow shade, plus two reds – oneyellowish and the other bluish – will providean extensive color range. The most frequentlyrecommended primary colors are BayferroxBlack 330, Reds 110 (yellow-shade red) and130 (blue-shade red), and Yellow 820 or 920.Incorporating two shades of red provides

greater color flexibility than only one shade;not all dark browns are possible with awarm yellow-shade red, nor are light tansor buffs always possible with a blue-shadered. In the example below, Bayferrox Redis combined with Bayferrox Black toachieve a mid-shade brown.

When using primary pigments at your factory, there is no need to premix them.Pigment metering systems are capable ofautomatically choosing the right pigment(s),measuring the exact quantity necessary, andtransferring the pigment to the concretemixer where the blending takes place.

In addition to offering the basic red, yellowand black colors, LANXESS offers customblends, and a wide range of standard brownshades, by premixing various primary pow-der pigments together.

Mixing Pigment in the ConcreteOnce you have selected the pigment formand the appropriate metering system tomeet your current and future needs, werecommend the sequence below for addingcolor to the mixer.

Since pigment powder is such a smallparticle-sized material, care must be takento ensure complete dispersion in the mix.As a general rule, a premixing of pigmentpowders or Bayferrox C, sand, and aggre-gates is most advantageous. The coarseraggregates act as “dispersion aids” and helpto distribute the pigment particles evenly.Then the specified amount of mixing water

Combination of Bayferrox pigments4%Bayferrox 110 4%Bayferrox 330 2%Bayferrox 110

+ 2% Bayferrox 330

1. Add sand and aggregates

2. Add Bayferrox powder or C grade pigment(s)

3. Mix for 30 seconds, minimum

4. Add cement

5. Add remainder of mixing water

6. Mix until homogeneous

CORRECT MIXING SEQUENCE FOR PROPER DISPERSION OF ANY TYPE OF BAYFERROX PIGMENT

7

is added and mixed until homogenous. Whenmaking your own pigment dispersions, orpurchasing pre-manufactured pigment slur-ries, a pre-wetting is recommended.Otherwise, problems may occur such asstreaking or the creation of pigment spots.If lightweight aggregates are used, it isnecessary to prewet the aggregates. Thisprocedure permits the water to fill thepores of the aggregates. The mixing thenmay be completed as suggested above.

Pigment Effect on Concrete QualityASTM C979 limits the amount of pigmentadded to concrete to 10%. Care must be usedwhen using weak pigments – those withlower tinting strength – because colorsaturation is not reached until much largeramounts of pigment are added. The amountof these pigments required to produce agiven shade can sometimes be so large thatthe increase in the amount of fines addedto the mix has a negative effect on thetechnical properties of the concrete andexceeds ASTM limitations.

Blaine is a relative measure of the specificsurface area of cement, but pigments donot follow this measure since their finenessdiffers depending on the type of pigment.As a general rule, however, most Bayferroxpigment powder would be approximately10 to 20 times finer than cement. But withthe Bayferrox pigment grades most com-monly used in concrete, these pigmentshave a nominal effect on the processingproperties of concrete considering the par-ticle size of the pigment, particle shapeand chemical composition.

Yellow pigments have a needle-shapestructure while red pigment is spherical andblack pigment is cubical. As such, yellowpigments have a higher water demand.This effect is noticeable only with pigmentloadings above 5%. If more than 5% yel-low pigment is added, this will lead to areduction in the effective water-cementratio and changes in the consistency of theconcrete. If you compare the addition ofyellow pigment to unpigmented concrete,it may be necessary to increase the amountof mixing water in order to obtain the sameconsistency, or workability, at higherpigment loadings.

What ElseAffects Color?

EfflorescenceAnything made from cement is susceptibleto efflorescence. It is important to note thatour Bayferrox and Chrome Oxide Greenpigments do not have any influence on thecreation of efflorescence, nor can they pre-

vent it from happening. To some degree,efflorescence always occurs. But when itappears on products that are colored, it seemsmore visible and customers complain more.

Primary efflorescence is the result of freelime in the cement being dissolved in themixing water and working its way, ashydrated lime, to the surface of the concretewhere it reacts with carbon dioxide in theair to form insoluble calcium carbonate.Secondary efflorescence is the samephenomenon, but it occurs after the concretehas cured when rainwater or dew bringshydrated lime or calcium hydroxide to thesurface. Therefore, porosity of concrete playsan important role in efflorescence. The lessporous the concrete is, the lower the tendency

SlumpWater-cement ratio 0.56

Nopigment

3% Bayferrox 820

3% Bayferrox 110

3% Bayferrox 330

15 in. 14 in. 15 in. 15 in.

6% Bayferrox 820

6% Bayferrox 110

6% Bayferrox 330

12 in. 14 in. 14 in.

8

Weathering of efflorescence

Weathered for1 year

Weatheredfor 14 days

for efflorescence to occur. The chemicalformula for this reaction is:

CaO + H2O Ca(OH)2

Ca(OH)2 + CO2 CaCO3 + H2O

How does it go away? In a subsequentreaction, the hard insoluble calcium carbonateon the surface of the concrete reacts withcarbon dioxide from the air that’s beendissolved in water, to form calcium bicar-bonate, which in turn, is soluble in water.This reaction can take from 15 to 24 months.Therefore, weather plays an active role inthe creation and removal of efflorescence.Also, since rain is necessary for removingefflorescence, this process will take muchlonger in arid climates.

More detailed information on this phenom-enon is available from LANXESS.

CuringSince curing temperature affects the colorof unpigmented concrete, it will also influencethe color of concrete that’s been pigmented.This is due to changes curing imparts onthe size and shape of the cement crystals.

Hardened cement paste, or stone, which isformed from the reaction between the mixingwater and the cement, produces calciumsilicate crystals of various sizes dependingon the curing temperature of the concrete. Itis the size and irregular shape of these crystalsthat affects the way light is scattered.Consequently, this changes the appearanceof the colored concrete product. As the curingtemperature increases, the crystal structureof the concrete becomes more irregular. Thisresults in more porous concrete, whichincreases light scattering, and the lighterappearance of the concrete. This color dif-ference is most apparent when concrete iscured at elevated temperatures comparedto concrete cured at ambient temperatures.

Whenever autoclaves are used, the colordifference (compared to normal room tem-peratures) is even more pronounced. Firstof all, even in unpigmented concrete, thecement crystals are affected, resulting in

extremely light gray concrete. When pig-ment is added to autoclaved products,especially black or dark brown shades, thesehigher temperatures may also affect thepigment itself. That’s because black ironoxide pigment starts to oxidize to brownpigment at 180˚C (356˚F) and eventually tored as the temperature increases. Therefore,if the concrete is autoclaved at 200˚C (392˚F),a color change from black to reddish brownshade is likely. Also, if dark brown pigmentis used (a combination of black and redpigments), a color change is likely for thesame reason. LANXESS Corporationoffers special temperature-stable pigments-Bayferrox 645T brown and Bayferrox303T black-which are capable of with-standing these higher temperatures. The useof any standard red or yellow iron oxide pig-ment is unaffected by normal autoclaving.

Influence of the curing temperature

Unpigmented

4% Bayferrox 820

4% Bayferrox 130

4% Bayferrox 663

4% Bayferrox 330

36°F 95°F

9

‡

‡

AdmixturesAdmixtures are those ingredients in concreteother than Portland cement, aggregates, andwater, that are added to the mixture immedi-ately before or during mixing. Given thisdefinition, pigments are classified as admix-tures. The most common admixtures are airentraining agents, water reducing agents,accelerators, mineral admixtures (pozzolans),and water repellants. Each type of admixturehas a different effect on the color – andappearance – of the concrete product.

Air entraining admixtures are used toimprove freeze/thaw durability by creatingmicroscopic air voids. These voids allowfor expansion and contraction of the frozenwater, thereby reducing scaling. These airvoids are present throughout the concrete.On the surface of the concrete, this causesan increase in light scattering, whichresults in the appearance of a lighter color.

Water-reducing admixtures are used toreduce the quantity of mixing water need-ed in the concrete mix while maintaining ahigh level of workability. The reduction ofwater increases the strength of the con-

Salts of wood resins

Some synthetic detergents

Salts of sulfonated lignin

Salts of petroleum acids

Salts of proteinacious material

Fatty and resinous acids and their salts

Alkydbenzene sulfonates

Improved durabilityAir Entraining

(ASTM C260)

Normally makes

color lighter

Calcium Chloride (ASTM D98)

Triethanolamine

Accelerator

(ASTM C494, Type C)

Accelerate setting & early

strength development

Darker color

Lignosulfonates

Hydroxylated carboxylic acids

(also tend to retard set, so accelerator is added)

Plasticizer

(ASTM C494, Type A)

Reduce water required

for given consistency

Initially darker;

reduced color effect

in later stages

Type of Admixture Material Desired Effect Effect on Color

Natural Pozzolans (Class N)

Fly Ash (Class F and G)

Other materials (Class S)

Pozzolan

(ASTM C618)

Reduce costs;

improved workability

and plasticity.

Typically lightens but

may darken due to

plasticizing effect;

inherent color affects

final color also.

Decrease permeability Possibly darkens colorStearate of calcium, aluminum,

ammonium, or butyl

Petroleum greases or oils

Soluble chlorides

Water Repellant

crete. This also results in fewer pores onthe surface. The decrease in porosity low-ers light scattering, which results in theappearance of a darker color.

Accelerators are added to the concrete mixin order to decrease setting time andincrease high-early strength. The additionof accelerating admixtures usually resultsin a darker color because of the early set-ting of the concrete, and because of that,the chance of the formation of efflores-cence is somewhat lessened.

Pozzolans are used to increase workabilityand to replace cement. In general, pozzolansare lighter and finer than Portland cement,which may result in a lighter color of theconcrete. Certain pozzolans, however, canbehave slightly as plasticizers. This plasti-cizing effect could allow for a reduction inthe amount of water that would result in adarker color.

Water repellants decrease the water perme-ability of the concrete. In general, there isno effect on the color of the concrete.

Admixtures by Classification

10

Printed on recycled paper Copyright © 2004 LANXESS Corporation 04961 10/04 BFRX (10M)

LANXESS Corporation

111 RIDC Park West Drive

Pittsburgh, PA 15275

1-800-LANXESS (526-9377)

www.Bayferrox.com

www.US.LANXESS.com

The manner in which you use and the purpose to

which you put and utilize our products, technical

assistance and information (whether verbal, writ-

ten or by way of production evaluations), including

any suggested formulations and recommenda-

tions are beyond our control. Therefore, it is

imperative that you test our products, tech-

nical assistance and information to deter-

mine to your own satisfaction whether they are

suitable for your intended uses and applications.

This application-specific analysis must at least

include testing to determine suitability from a

technical as well as health, safety, and environ-

mental standpoint. Such testing has not neces-

sarily been done by us. Unless we otherwise

Note: The information contained in this bulletin is current as of November, 2004.

Please contact LANXESS to determine if this publication has been revised.

Health and Safety InformationAppropriate literature has been assembled which

provides information concerning the health and

safety precautions that must be observed when

handling the LANXESS products mentioned in this

publication. Before working with any of these

products, you must read and become familiar with

the available information on their hazards, proper

agree in writing, all products are sold strictly pur-

suant to the terms of our standard conditions of

sale. All information and technical assistance is

given without warranty or guarantee and is sub-

ject to change without notice. It is expressly

understood and agreed that you assume and

hereby expressly release us from all liability, in tort,

contract or otherwise, incurred in connection with

the use of our products, technical assistance, and

information. Any statement or recommendation

not contained herein is unauthorized and shall not

bind us. Nothing herein shall be construed as a

recommendation to use any product in conflict

with patents covering any material or its use. No

license is implied or in fact granted under the

claims of any patent.

use, and handling. This cannot be overempha-

sized. Information is available in several forms,

e.g., material safety data sheets and product

labels. Consult your LANXESS Corporation repre-

sentative or contact LANXESS's Product Safety

and Regulatory Affairs Dept., Pittsburgh, PA.