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Concrete Form Release Agent
Concrete Form Oil
Concrete Mould Oil

( Chemical Guide about Concrete Form oil )

  1. What are concrete form release agents ?
  2. Very popular classification of form release agents
  3. How to apply concrete form release agents ?
  4. Problems on manufacturing concrete products .
  5. Problems when separating concretes from forms
  6. Problems when concrete build-ups observed on forms
  7. Problems in hardened concrete product surfaces
  8. What kinds of ingredients are contained in concrete form release agents ?
  9. Form oil behaviours between forms and concretes
  10. What factors may affect form oil performance to release forms and make concrete product surface even ?
  11. FAQ about concrete form oils
  12. Remarks

The information and statements herein are believed to be reliable but are not to be construed as a warranty or representation. Users should undertake sufficient verification and testing to determine the suitability for their own particular purpose or products. (O.Yamanaka)

1.What are concrete form release agents?

    (1) What are concrete form release agents ?

  1. They are the materials used on the concrete form surfaces to prevent the concretes from sticking to the forms or formworks.

  2. They prevent forms or formworks from bonding to concrete products.
    They can release or part forms smoothly and lubricantly . If they are not applied , it will be very difficult to be seperated concrete from forms so easily, troubles and problems will happen so at once.

  3. They make concrete product surface even with less bugholes, stains and irregularities .

  4. They protect forms or formworks and keep their lives much longer .
    (In other words, they act as a bond breaker and form cleaner ; are non-staining ; cut cleanup time ; eliminate voids, defects and build-up of concrete and mortar ; protect forms from rusting.)

  5. chemical release for concrete forms that effectively prevents bonding of concrete to steel, aluminum, plywood or composite forms. Composed of organic chemicals that react with the concrete or adhere tightly to forms to prevent adhesion and provide a quick and easy release.

  6. The terms used similarly are as follows ; concrete form oil, concrete form release agent, concrete form releasing agent, concrete mould oil, concrete mould release agent, form release agent, form releasing agent, form oil, mould oil, formwork release agent.

    (2) What may cause daily problems in manufacturing concrete products ?
    ( Analizing these causes is the starting point to solve daily problems.)

  7. The materials (such as cement content in mix proportion , aggregates, kinds of cement, concrete admixture , water and other materials )and each process of manufacturing concrete products (such as of casting , vibration conditions , curing , workers , working style , product process , weather , temperature , form setting place , etc .) affects actual quality of the concrete products .
    It is not true that form release agent is the only cause of troubles and problems of manufacturing concrete products. Understanding it, when we analize the claims, problems should be naturally analized throughout all the processes.

  8. When troubles may occur, observe the finished concrete surface and forms. Then analize their causes of problems as possible as naturally as the products might be talking to us.

  9. When troubles caused from form oils frequently may occur, study fundamental knowledge of form oils ,and when using form oils, use them much more effectively, so troubles and problems will be less reduced.

    (3)When problems may occur causing from the form oils , troublesome problems can be broken off or minimalzed after one may master form oil problems how to solve .

2.Very popular classification of form release agents

Concrete form oils are usually classified into water soluble type, oil soluble type, and emulsition type form release agents according to the appearance and solubility.

Appearance Solubility How to use Applications
tanned oily liquid Oil soluble use direct cement and concrete manufacture, civil engineering and construction , cellular concrete, foamed concrete
oil soluble dilute with oil cement and concrete manufacture, Vi-cone、 long pitch corrugated asbestos slate
water soluble dilute with water large size products, high flow concrete products,centrifugal product
segment, wood-wool cement boards、sizings
milky white liquid or paste water soluble use direct cement and concrete manufacture, civil engineering and construction
water soluble dilute with water cement and concrete manufacture, centrifugal products
oil soluble dilute with kerosine cement and concrete manufacture, Vi-cone
tanned solution oil soluble rezineous (use direct) centrifugal products, cement and concrete manufacture
water soluble wax type(dilute with water) cement and concrete manufacture, civil engineering and construction

3. How to apply concrete form release agents ?

    (1).Clean up forms .
    ・Clean up forms before applying ( painting or spraying ) form oils.
    ・When build-ups are on forms too much , concrete product surfaces will not be finished uniformly.

    (2). Apply adequate amount of form oils. Don't apply too much so as to cause trouble and problems.

    ・The standard amount of form oil application may be decided by checking the finished concrete product surfaces.
    ・Make sure whether form oils are painted evenly. Unpainted parts on forms will occurs bonding forms to concrete products.
    ・When applying too much form oils, oil stain and not-hardened concrete parts may be often observed on the part of bottom and corners. Excessively applied form oils should be wiped off surely.

    (3). When form oils used now will be stopped using and new maker's form oils will be going to be applied , use up all of form oils used now before applying new form oils. Mixed using of two types , problems may sometimes occur; stain will appear and more voids may appear . Sometimes the balance of active ingredients may detroyed. and forms may stick to concrete products .

    (4). When new forms are started to be used , warm up new forms. Wipe off rustproofing oil with oil soluble type form oil or kerosine , then apply form oil and cure new forms without concrete pouring. After that treatment, the new forms will be warmed up to be used for daily work. If dissatisfied results arises, once more apply form oil and cure without pouring concrete.

    (5.) The vacant container (drum or tank) should be capped not to be mixed with other materials(rain,dust,cement etc).

    (6.) Used form oils should not be backed to unused ( virgine ) form oils . When backed into new oils , cement-alkali in used form oils will react with form oils , and form metallic soap or adsorbent cement-oil particles. At that case the parting strength of form oils may drop down to much extent . The activity of Used form oils is not equal to New virgine form oils. Sometimes down to 30%. In this case accidents may frequently occur.

    (7).When applying emulsion type (water mixing type) , the contents should be thoroghly agitated before use and even whether the contents may separate or not, make sure that they are even, and then use them for daily work. Like this workstep should be routined to avoid water soluble type form oil accidents. (When separated oil is sprayed over cast, daily constant form parting effect will not be avaible.)

4.Problems on manufacturing concrete products .

The problems may be occurred in following cases such as follows:
(1) Selecting or applying method of form releasing agents may not be suitable.
(2)The process of releasing forms from concrete products cannot be kept running smoothly.
(3)On the parted forms much concrete built-ups are observed. Cleaning work takes too much time and effort.
(4)The surfaces of hardened concrete products are not finished equally and beautifully.

Points of Troubles and Problems Problems in the process of manufacturing
1.Selecting , applying and stocking methods of form oils They may not be applied in suitable conditions to get good concrete products. For example , too thin or too thick . Oder is not mild. The fluid may sometimes become gel and separate
2. The process of releasing forms Forms cannnot be parted smoothly. The form oils may not have sufficient lubricity and releasing power.
3.The forms just after separated from hardened concrete products Concrete build ups are observed. In case of too much build ups , form cleanworks are troublesome and it may take time too much to use the forms more times.
The characteristics properties of build ups are observed in two cases as follows ; one is soft and brittle , easy to remove with weak brushing power and the other is hard and hard to be removed with weak brushing power . In both cases ,build ups should be cleaned up. If no cleaning works are done, the build ups will change much harder not to be able to be cleaned up with ease and will grow much thicker. They will cause oil stain on concrete products.
4.The concrete product surfaces after separated from forms Oil stains are observed on the concrete surface
Discoloration will occur to a little dark brownish
Much bugholes are observed.

5.Problems when separating concretes from forms

Problems Sources of troubles Causes Follow-up actions
Forms may sometimes bond to concrete products. Defects may be observed . Form releasing processes are not kept running smoothly.
Form oils Not applied uniformly.There are unpainted parts in forms. Make sure form oils are applied uniformly.
Applied quantity of form oils are too little and not adequate to release well. Apply adequate amount of form oils.
Releasing power may be too weak. Test more stronger form oils
Curing Inadequate(Much amount of soft concrete buildups are observed on forms) Curing time→ Adjust
Curing temperature→ Adjust
Excessive curing. Form separating works may not be done smoothly. Adjust curing conditions
The film layers of applied form oils will be destroyed. Vibratings in molding conditions may be too strong. Adjust molding conditions
The forms which form oils are applied may be set for long time before fresh concretes will be poured into mold. Recoat form oils or
Change form oils which can release after long intervals.
The forms are too hot to retain adequate amount of form oils. Cool so far as time permits

6. Problems when concrete build-ups observed on forms .

Problems Sources of troubles Causes Follow-up actions
Much amount of build ups is observed
Hardened build ups Cleanings are inadequate Clean up forms
As the result of overcuring, form oils are absorbed into concrete products . Then luburisity will be lost. Adjust curing time
Inadequate form oils applied Apply adequate amount of form oil.
Form oils are adsorbed into concretes . Then form oil films on the forms are destroyed. A little more stronger one should be tested.
Soft build ups which are not in hardened state or will harden from now Inadequate cleaning up , then build up will deposite. Clean up forms surely
Shortage in strength of concrete surface Cure adequately
Applied too much form oils Spraying as necessarily thin as possible. Excessively applied form oils should be wiped off.
The strength of form oil is too much stronger than necessary case. Adjust or test other oils which is weaker than used now.

7.Problems in hardened concrete product surfaces

Problems Phenomena Causes Follow-up actions
Bugholes on cocrete products
There are a lot of little bugholes which concrete embraced form oil into the surface. Acid value of form oil is too high .
The viscosity of oil is too much.
Choose other form oil which has lower acid value or lower viscosity than used now.
Excessive amount of form oils are applied. Adequite amount of form oil should be sprayed.
Small voids are observed , which may be from air bubbles. When cement paste which covers bugholes on concrete product is taken away to the formwork, the form releasing power of form oil is too weak. If form oil is diluted with water, down the dilution ratio with water. More thicher diluted form oil shows better form releasing power.
Change oil more strong type form oil.
Spray a little more thicker.
When cement paste which covers bugholes on concrete product is staying on concrete surface, the form releasing power of form oil is OK, but the power of antifoaming is not adequate Change form oils which has more strong power of antifoaming.
Add a little amount of adequate antifoam agent.
Curing steps are too speady started. Precure so far as time permits.
Relatively big voids are observed , which may be from air bubbles or voids from another causes. The conditions of vibration-molding concrete are inadequate. Adjust molding conditions
The workability of fresh concrete is't adquate . Slump may be too little. Adjust flowability. It should be reexamined to mix ratio of fresh concrete materials.
Stain on concrete products
When fresh concretes are poured into forms and vibrated , the excessively applied form oils will arise oil stains and discolorations from bottoms to a little upper parts like a little volcanoes. Excessive amount of form oils are applied. Spray uniformly and adequate amount to release forms from concrete.
The finished surface of hardent concrete product is a little dark-brown. The parting power of foam oil is too strong. Test more weak form oil
Stains are observed when concrete work processes are done outdoors. The applied form oils will react with oxygen under ultraviolet ray and their form releasing characteristics will be changed. Use form oil which is durable to ultravoiret ray.
Screen sunright.

8.What kinds of ingredients are contained in concrete form release agents ?

Materials Ingredients Effects ,rollings Sticking power to forms
Mineral oils kerosine lubricant
solvent for oil soluble type form oils
Adjust viscosity of oils.
very weak
spindle oil
trans oil
Releasing power is weak.
Adjust viscosity of oils.
very weak
machine oil lubricant. Releasing power is weak. sticky
turbine oil lubricant.Releasing power is weak. sticky
moter oil lubricant. Releasing power is middle. sticky (strong)
cylinder oils lubricant. Releasing power is strong. more sticky
active additives higher fatty acids releasing, antifoam, lubricant, rust-proofing strong
resin acids releasing , antifoam, lubricant, rust-proof strong
waxes releasing, carrier of parting materials strong(middle)
fatty acid derivatives lubricant, releasing sticky(middle)
synthetic resins releasing effect sticky to forms(strong)
supplementary additives fat, fatty acid esters oiliness improver(specially in winter) weak
surface active agents antifoam, emulsifier, wetting agent weak
petroleum sulphonate emulsifier, rust-proofing weak
polymers(polybutene etc) oiliness improver sticky(weak)
dyes coloring agent weak
carrier (in case of
water soluble type form oils)
water diluent, lubricant weak or none

9.Form oil behaviours between forms and concretes ( Reaction mechanisms )

Commercially you can get many kinds of form release agents (= form oils ) from makers. What differences are in them? In that case you only need three categories to classify most release agents effectively :
Reactive ( or chemically active ) types, Barrier types and Lubricant types.

Category of form oils Form oil behaviour between forms and concretes ( Reaction mechanisms ) Merits, advantage Demerits
Reactive (chemically active) type Chemically active ingredients in applied form releasing agents on forms will react with cement alkari to form metallic soap. This reaction proceeds in two steps.First, higher fatty acid in form oils will react with NaOH and KOH and form water soluble soaps. This substance will antifoam air bubbles.
Secondly, this water-soluble sodium- or pottasium salts of fatty acids will eact calsium ion immediately to form metallic soaps which are insoluble in water. These materials will act as burriers not to bond forms to concrete products.
( Commercially it is said that higher fatty acids in form oils can react directly with calsium ion to form calsium salts of higher fatty acids. In normal conditions this reaction may not occur. That isn't right.)
The parting power can be adjusted by adjusting the amount of higher fatty acids. Antifoaming efficiency is excellent in general. When form oil is oversprayed, oil stain is observed frequently and a corner or bottom part of concrete product doesn't harden and sometimes heavy build up will appear.
Barrier(non-reactive) type The reactivity of form oils with cement alkari is poor. The polar substances in form oils will be adsorbed or sticked to forms , which will adsorb cement particles and other fine materials. These intermediates will act as barriers which will prevent forms from bonding to concrete products . After separating forms,the build up is observed a little in general. Even if these oils are applied too much excessively , oil stains will not be observed so much as when chemical type oils are applied. Bugholes are much more observed than in case of chemical type.
Lubricant type Lubricant form oils will be weakly adsorbed phisically to cement particles and to forms. They will act as lublicants between moldpress surfaces and fresh concretes . After concrete products are cured , they should not be sticked or bonded to each other. The lublicity can be adjusted. The performance of oil soluble type form oil might surpass in water soluble(or emusion type) form oil.
(Mixed type) (Mixtures of chemical reactive type and physical type might be often observed. They might belong to chemically active type.) (Adjustable) (Rather a little more bugholes are observed than in case of chemical type.)

10.What factors may affect concrete form oil performance to release forms and make concrete product surface even ?

Level of influence:severe→●●●、remarkable→●●、light→●、negligible →○
Specific cause of problem Various factors Seperating Build-up Bugholes Color of concrete product
Form release agent itself Choice, viscosity(high, low), chemical active ingredients(rich, poor ), chemical reactive type or physical type, lublicant oil(high vis. , low vis.), applying method, applied amount (excessively sprayed , inadequitely sprayed ), set place of painted form , storage of oil, re-using of used form oil ●●●~○ ●●●~○ ●●●~○ ●●●~○
material of forms ceramics, steel
aluminium, galvanized steel
concrete panel, plywood
synthetic resin overlayed formwork(epoxy-, polyurethan-, polyester)




kinds of cement ordinary portland cement, high-early-strength portland cement, blast furnace cement ●●~○ ●●~○ ●~○
cement content in mix proportion 400~500kg/m3, 270~350k/m3 ●●~○ ●●~○ ●~○ ●~○
concrete admixture When fresh concrete is exchanged from plain concrete to admixtured concrete
when substituting admixture
when admixture(AE water reducing agent) is substituted with high fluid plasticizer
espicially in case of melamine derivatives, naphthalic derivatives and polycarboxylic derivatives
●●●~○ ●●●~○ ●●●~○ ●●●~○~○
admixuture materials(= fine powders) When amount of fine particle (for example calcium carbonate)is increased. ●●●~○ ●●●~○ ●●●~○ ●●●~○
setted forms interval between painting oil and pouring concrete short
for 1 ~4 hours
a day ~few day
●●~○ ●●~○ ●~○ ●~○
the place where the forms are set. indoor working process, outdoor working process especially in case of the place which is exposed to ultraviolet rays from the sun. ●●~○ ●●●~○ ●●~○ ●●●~○
sistem for manufacturing concrete products Automatic line system, manufacturing system with molding forms which are set in the predetermined place or moved step by step to the working station ●●~○ ●●~○ ●●~○ ●●~○
Product shape, type , size ordinary type products(large size, middle size, small size) or
the forms which are specially patterend indented or particular types (irregular types)
●●●~○ ●●●~○ ●●●~○ ●●●~○
How to design concrete molds Concrete pouring direction:The mold is differently designed vertically or horizontally. ●~○ ●~○ ●~○ ●~○
Fresh concrete Concrete mixing ratio
Mixing method
Consistency(SL,Flow,Air content)
Time lag of pouring fresh concrete
●●● ●●● ●●● ●●●
How to mold Form vibrator(table vibrator, side vibrator, internal vibrator, back and forth vibrator)
(low frequency vibrating , high frequency vibrating , vibrating molding time)(no vibrating~weakly vibrating molding)
centrifugal rotation molding
press molding、 vibrating and press molding
●●●~○ ●●●~○ ●●●~○ ●●●~○
Curing Time between molding and curing
How to cure(Steam, gas, autoclave, narural )
Curing time
●●● ●●● ●●● ●●●
Form release, form seperating Form is opened or almost closed (a little opened )
The direction of form seperating
●●~○ ●●~○ ●~○ ●~○
Curing after form seperating forms How to stock
Weather・temperature・especially very cold winter
--- --- --- ●~○○
Direction of separating forms from concrete vacuum separating upwards or sidewards ●●~○ ●●~○ ●~○ ●~○
Environmental demand Environmental pollution ●~○ ●~○ ●~○ ●~○
Seanonal change viscosity change of form oil, in winter season using oil type forming oil instead of emulsion type ●●~○ ●●~○ ●~○ ●~○
When sepparating form when the intensity of product surface is low. (tunnel, sewer) ●●●~○ ●●●~○ ●~○ ●~○
Materials situation Environmental regulation, demand of purity of refining material oils、 carcinogenic or not ●●~○ ●●~○ ●~○ ●~○

11.FAQ about concrete form oils

(1)About form release agents

Is there Japanese industrial standard regarding to form release agents? No.there isn't in Japan. The standard is maker's self-standard.
2.How can we test performance of form release agents in manufacturing concrete products ? Lubricant test methods are only applied to determine physical or chemical characteristics of form oils. (density, kinetic viscosity,color, flash point etc.)
If needed, concrete form oil tests are examined in laboratory scale, but these tests are only basic and not final and perfect tests.
3.What kinds of laws are there to deal and use form oils.? Fire Defence Law, Clean Water Law, Sewage water Law, Marine Pollution Prevention Law, Waste disposal and Public Cleaning Law, Labeling Duty On Industrial Safety and Health Law, MSDS, Law Concerning Examination and Regulation of Manufacture and Handling of Chemical Substances
4.What are the merit of using oil soluble type form oils? These types can be used in all seasons. The build up is much less than in case of applying emulsion type.
5.Are emulsion types applicable to form release agents satisfactory? Concrete admixtures were recently made an excellent progress .Enlargement usage of them, form oil performance was promoted and its good-looking concrete product surfaces are frequently better than in oil type . Therefore the extents to use emusion type form oils are growing up and now they are recognized as members of goods necessary to manufacture concrete products .
6.What is the merit of using emulsion type form oils? Comparing emusion type form oil with oil type one, the surface of concrete product is more white and there are not so many bugholes .The surface is more smooth. Emulsion type form oil has now come to work effectively with its adeguate separating power. When it is sprayed, the mist of form oil is heavier than in case of oil type, so it doesn't spread so wide as in case of oil type. Working condition will be improved.
7.How to use more efficiently emulsion type form oils.? When emulsion type form oil is used, the form oil emulsion should be stirred while spraying process is on being. Used form oil should not be back to new form oil. If it is mixed, it's balance will change and the components pretend to separate . In winter in order not to be froze, emulsion should be kept warm if necessary.Overspraying mold oil, overpainted oil will cause oil stain and retard concrete hardening reaction, so over amount of oil should be wiped off.
8.What is the demerit of using emulsion type form oil? In water emulsion type form oil should be keeped warm. On too severe low temperature conditions, water is frozen and sprayed is frozen. At that it cann7T used. When working time is over, form oil in the pipeline should be outto be empty.
9.How to apply forming oil Apply thinly (adequately). Swipe off oversprayed oil. Try different spraying methods, and choose the best way which is profittable to the factory.
10.The form oil is too viscous to apply. Test less viscous form oil. Use after form oil is warmed. Make its viscosity down with low viscosity oil(ex. kerosine) 5 to 10 % of all.
11.When form oil is applied and a long time (a day or more ) will pass by, the separating effect will not be adequate. Use form oil that is able to release under such conditions. When sprayed form oil drops down with elapse of the time, there are some forms in commercial which are able to release forms .In that case it sometimes contains viscosity improvers.
Respraying before pouring concrete.
12.Is the film layer on the form oil durable to excessively severe vibration? It can not be durable. The thin layer of form oil is destroyed. The strength of form oil performance has a limit.
13.(Civil engineering)The form oil is sprayed to unwanted part(ex.reiforcing steel). Is the painted part is safe or hamful to the next step of concrete-working? Form oils should not be painted or sprayed to unwanted places.If painted, the oil should be removed.
14.(Civil engineering)The form oil is sprayed to plywood form with thicker concentration than usual dilution ratio. Is it harmless or detrimental to the later working? The overlayed or over amount of form oil will frequently contain the material which would retard concrete hardening reaction. So, form oils in that case should be removed and then sprayed once more with standard form oil whichis diluted in standard ratio.
15.(Civil engineering)The pollystyrene form is sprayed with emulsion type form oil. At that time the formwork is rained so much. In fear of washout, respray or repaint form oils.
16.The oversprayed form oil is recovered. Is this recycled form oil equal to fresh form oil?? The composition of recycle oil is not equal to fresh oil. A part of ingredient is adsorbed or reacts with cement alkali, and then form the other material or complex. The concentration of components is reduced. The fine powders in concrete blending comes to be mixed n into oil-alkari complex part.

(2)Concerning vibration molding and curing

1.Effects of vibrating molding on releasing forms. (shortage in bibration →bugholes, oil stain)
(excess→hard to seperate forms from concrete 、Forms are built up with hardened concrete or bonded to concrete product in extremely severe condition.)
2.In case of being short in surface strength because of inadequate curing, what does it effect on releasiong forms? Concrete builds up to forms(soft build up ,spot build up
Concrete product finished surfaces (dappling of oil stain, slightly dark coloured, deep oil stain.
3.What effect does concrete-overcuring cause on releasing forms? The form oil will be absorbed into concrete product surfaces,and then lose its adequate lubricity to release forms. Form separation will not be able to be done with ease. Just before the step,the release is good and product surface is white.Farther more oil stain is not observed or not to be mentioned oil stain.

(3)When separating forms

1.Hard to release forms The forms is sticking to concrete product. It cannot be separated easily with lubricity.→(Spray form oil a little thicker.)(Warm forms before separating.)(Adjusting curing)(Change form oil with other more lubricant one.)
2.When separating, the deep pitch part of product is damaged. ・The taper of formwork is too tight(or small)→Adjust formwork(ex.grind down ). Separating formworks to horizontal direction.
・Hard to separate→Test other oil with more lubricity. In exterme case use grease or solvent type form oil should betested.
3.Hardened build up is observed on forms. ・Form oil may cause like that problem.(Shortage in amount of sprayed oil.→Adjust amount of form oil.
Shortage in power of releasing forms→Test stronger type form oil.
In shortage in viscosity of form oil.→Inclease viscosity of form oil.
Interval time between painting form oil and pouring concrete is long.→Test more VI improved form oil.)
・The vibrating conditions may cause .(The conditions is too stronger.→Adjust.)
4.Soft(=Not hardened )build up is observed on formworks. ・Form oil may cause.→(Overspray form oil.→Super adequate amount of form oil.) (Power of releasing formworks is excessive.)→Test weaker oil) (Excessive viscosity of form oil →Test improved type which has lower viscosity.)
・Curing may cause .→ (Strength of concrete product surface is not sufficient to be separated.)(Shortage in curing in cold season of climate.)→(Adjust blending ratio with high-early-strength portland cement)
・Rapid curing(rapid rising of formwork temperature)may cause to make product surface uneven .The thin layer of entrained air covered with cement paste may migrate rapidly up to formwork and be destroyed.→Adjust of inductive curing and curing conditions.
5.In automatic line , too much build up is observed. (Too much form oil is sprayed.→Adjust)(Reactivity of form oil is too much.→Test oil with lower asid value.)(Additives such as antifoam might be too much.→Test more simple type form oil.)(Test physical type form oil.)
6.Why soft build up is formed? when releasing agent may be a cause of concrete build up:The form oil on the form work reacts or adheres with fresh concrete. Then mixture causes retarding of cocrete hardening reaction and forms concrete build up.
7.Formwork rusts. ・Overlayed black iron oxide film is lost→(Renewal of formwork.)(Test more antirust oil.)(Inprove curing environment not to be rusted by much of water drops.)
(・When emulsion type is now used, formworks tends to rust.→Change form oil more antirust form oil.Sometimes oil type form oil is used, then no rust might be observed.)

(4)The surface of concrete products

1.What is the powder observed on concrete products and formworks? That is a mixture consisting of next materials; ①metallic soap or co-agglutinate which form oil and fresh concrete reacts or adheres to each other ②fine particles 、③fine sand 、④mud,⑤cement hydrate、⑥a part of form oil(oil and additives).
2.Why is cement paste which covers pinholes sticked to formwork? ・Overspraying of form oil may cause.→Adjust amount of form oil to be sprayed.
Form releasing poweris excessive→①Adjust or change it with a little weaker form oil)
・Shortage in poor releasing power may cause→Strengthen form releasing power. In case of emulsion type form oil, down the water-dilution ratio.②In case of oil soluble type form oil →Test stronger type or paint more thickerly, or use more viscous one.
・③In case of shortage in strength of product surface may cause , adjust curing conditions or blending and adjust blending ratio with high-early-strength portland cement.
3.Much bugholes are observed. ・Form oil may cause.(①In case of shortage in antifoam →Test other oil with more antifoam performance . ②Add antiform agent 1~2% to foam agent used now.)
・Fresh concrete when admixture is changed may cause. Especially this case is most frequently occured. The admixture is changed, but form release agent is not changed or improved in order to fit newly adopted concrete admixture. In that case usually used form agent may not serve its purpose to make concrete product surface even. Test form oils which serves to be the concrete product which has beautifully finished surfaces.
・In case of casting process→Adjust casting conditions.
4.The surface of concrete product is a little dark-colored. ・Compatibity of concrete admixture may be changed. In some case , its color is improved to desired one.
・Form agent may cause →①Oil is too strong.→Test adjusted type.②Overspraying→Adequately spray
・Curing may cause →Adjust curing conditions.
・Impurities in aggeregates may cause.→Form agent could not improve its states
5.Oil stain is observed. ・Form oil may cause.①Over spraying→Wipe off or remove with proper solvent.②Form oil is too strong.→Adjust form oil or test weaker one.
・③Form release agent could react with oxigen in air under UV radiation. By outdoor casting concrete , formwork is sunshined. Then form oil will be changed to the form oil which would be supposed to be partially oxidized or decomposed or condensated or polymerized with more acidic substances by UV. This phenomena could be observed only 20minutes after form oils being applied even on a cloud day. This oil layer on the forms will frequently form much build up on forms. In the case of outdoor works more UV-durable type form releasing agents should be applied.
6.There are >10mm bugholes on concrete product. May these be finished to even by means of changing form oil? In some cases, emulsion type may control the formation of like that bugholes. The holes which the entrained air bubbles will gather and form will be covered with mortar paste. but it is frequently crazed or drop down. This thin coating is often fragile. Adjusting and improving concrete casting conditions should be tested. In some cases concrete blending ratio should be restructered.
7.What is oilbugholes? Form oil is sprayed on formwork surface. Oversprayed oil will drop down to the formwork bottom place. When bibrating casting is started, that oil rised upwards after entrained air bubbles. There oil may form fine cubic particles.After concrete products hardens, the oil will be absorbed into concrete and leave behind very fine cubic holes(~5mm). Like this fine holes may sometimes calls oilbugholes.
8.How to cotrol the formation of oilbugholes? (Wipe off the oil which is oversprayed and dropped down. )(Test form oils.
9.Oil stain streak is observed vertically. It is observed along the place where vibrators are set or along reinforcing steel.(Form oil cannot clear this problem only itself.)

(5)et alia

1.May efflorescence be able to be controlled ? It is observed in winter season. After it rains, it can be frequently observed. May form oil be able to stop efflorescence from concrete products? It is impossible to control it only by form release agents. (Some kinds of form oil may a little retard efforescence, but cannot control it. If concrete is water proof, its phenomenon will be controlled. If form oil is enriched with such waterproogfing agent, concrete surface will not be waterproof. Because, formwork and fresh concrete is touching each other . Concrete surface is wet and not so porous to absorb only waterproofing agent.
2.Stains or colour changes in curing concrete products. Shortage in curing, rained just after separating、temperature falling down、 curing place may cause . Form agent may not be able to solve this problem.


References concerned with Concrete Form Release Agents and Concrete Surface Problems

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References Concerned with Concrete Form Release Agents
Biodegradable Lubricant Materials
Rubber Mold Compounds & Plastics. Rubber Mold Compounds and Plastics Technology
(Nicholas J. Sarra, Distributor and Consultant for all Manufacturing, Mold and Model Makers, and Casters.)
Mold Release Agents For use in all industries( Nicholas J. Sarra Distributor and Consultant)
Today's Standard In Concrete Form Panel Performance(Simpson Plywood) Simpson MultiPour Plus