Fair Faced

02/2012

Doka Knowledge Transfer 

999453102 en-GB

Fair-faced concrete Low-void concrete surfaces

94531-804

The Th e Fo Formw rmwork ork Ex Exper perts ts

Doka Knowledge Transfer Fair-faced concrete - Low-void concrete surfaces

Introduction tion Introduc-

© by Doka Industrie GmbH, A-3300 Amstetten 2

999453102 - 02/2012 The Formwork Experts

Doka Knowledge Transfer Fair-faced concrete - Low-void concrete surfaces

Introduction

Contents 4 6 10 14 15

General remarks Release agent Concrete Usage on site  Annex

999453102 - 02/2012

3 The Formwork Experts

Doka Knowledge Transfer Fair-faced concrete - Low-void concrete surfaces

General remarks Criteria applicable to the surface of fair-faced concrete surfaces with high and very high requirements: ● smooth concrete faces ● Low-void (maximum proportion of voids 0.3 - 0.6 % of test surface) ● even concrete surface, of uniform appearance Minimal surface voidage is also desirable for concrete surfaces not planned as fair-faced concrete. Keeping in step with the trend toward low-void concrete surfaces entails dealing correctly with the following factors: ● Formwork sheeting ● Release agents ● Concrete ● Working the concrete

The production of high-quality fair-faced concrete requires a great deal of specialist skill and meticulous care on the part of everyone involved in the process, underpinned by smooth co-operation throughout. Factors influencing fair-faced concrete and concrete surfaces On construction site ● Concrete ● Quality Planning ● Release Bid solicitation agent ● Working In advance

Influencing factors

● ●

Environmental conditions ● ● ● ●

Temperature Precipitation Wind Sunshine

See the "dopi" Lotus Notes tile, user information/practical information publication entitled "Forming fair-faced concrete".

Fair-faced concrete classes in Germany (DBV/BDZ bulletin) and Austria Fair-faced concrete class

Designation Ger Austria many

Concrete surfaces without engineering requirements

Description No special architectural features

Fair-faced concrete with low requirements

SB 1

SB1

Low design-related requirements

Fair-faced concrete with normal requirements

SB 2 SB 3

SB1 SB2

Normal design-related requirements High design-related requirements

SB 4

SB3

Very high design-related significance

Fair-faced concrete with special requirements

Examples

Basement walls, garage walls, retaining walls Stairwells, bearing walls Facades Representative structural elements

Areas of responsibility The manufacturer or supplier of the concrete is responsible of ensuring that the product is mixed in compliance with the applicable standards.  As of handover to site, the concrete-placing company bears responsibility for the following: ● Placement in compliance with applicable codes and regulations ● Compaction ● Post-pouring work ● Further protection of the concrete structural element Whenever fair-faced concrete or concrete subject to high requirements in terms of the finished surface is concerned, the concrete manufacturer must be notified accordingly and integrated into the overall construction process so that the best possible finished result can be achieved.

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999453102 - 02/2012 The Formwork Experts

Doka Knowledge Transfer Fair-faced concrete - Low-void concrete surfaces

999453102 - 02/2012

5 The Formwork Experts

Doka Knowledge Transfer Fair-faced concrete - Low-void concrete surfaces

Release agent See the "Doka Knowledge Transfer" Lotus Notes tile and the detailed information on "Release agents".

Proportion of pores on the concrete surface in % depending on the used type of release agent (Mineraloil with additives/ Aqueous release emulsions) Mineral-oil with additives

Aqueous release emulsions

Types of release agent and how the various release agents work Release agents are indirect materials used in construction; they are applied to the formwork sheeting before the fresh concrete is poured. Their primary purpose is to facilitate demouldability, in other words the separation of the formwork sheeting from the set concrete. When it comes to fair-faced concrete, the release agent has another part to play as well. In these circumstances the surface of the concrete has to meet certain aesthetic requirements: ● Low surface voidage (low proportion of blowholes). ● No concrete adhesion to the sheeting. ● High level of colour uniformity over the visible surface of the concrete. The release agent forms the boundary film between the formwork sheeting and the concrete. Depending on the composition of the concrete, this film has a very considerable effect on surface finish and quality, particularly with regard to the intensity of surface voidage at the exposed faces of the finished concrete structure. Types of release agent: ● Mineral oils and vegetable oils, without additives, have a purely physical separating effect. ● Mineral oils with additives have this same physical separating effect plus a chemical releasing effect. ●  Aqueous releasing emulsions do not work in the same way as vegetable or mineral oils. They ensure highly effective de-aeration along the concrete surface. Distinctions are drawn between the following types product: ● Hydrophobic products - Mineral-oil-based and vegetable-oil-based products ● Hydrophobic products - Aqueous release emulsions Regarding non-emulsions and oils, moreover, viscosity has a crucial part to play in the achievement of low surface voidage. Viscosity depends on the temperature at which the concrete is worked and on ambient temperature.

6

0,95 %

   R    5  ,    2    4    I    M    E    C

94531-811

Mineral-oil with additives

   t    i   s   a   u    l    F    %    5    1    h    t    i   w    R    5  ,    2    3    S      A    /    I    I    M    E    C

0,86 %

94531-812

0,09 %

94531-813

Aqueous release emulsions

0,10 %

94531-814

999453102 - 02/2012 The Formwork Experts

Doka Knowledge Transfer Fair-faced concrete - Low-void concrete surfaces

Viscosity measured at 5, 20 and 30 °C 94531-800

250

236,4

   ]   s 200   a    P   m    [ 150   y    t    i   s   o 100   c   s    i    V 50

180,5

D

174,3

131

 A

104,5

81,9 B

29,4

C

65

78,2 57,3

27,2

24

0 2

4 6

8 10 12 14 16 18 20 22 24 26 28 30 32

Temperature [°C] A Mineral oil B Mineral oil with additives C Emulsion D Rapeseed oil

 As the graph shows, unmodified vegetable and mineral oils evince very severe temperature-dependent fluctuations in viscosity.  As regards temperature-related fluctuations, mineral oils with additives and aqueous emulsions exhibit a more restricted bandwidth of viscosity fluctuation. Surface voidage for thinly applied release agent, non-absorbent formwork sheeting surface and variation of fresh-concrete temperature    ]    %    [ 2   a   e   r 1,65   a   e 1,5   c 1,18   a    f   r 1   u   s 0,58   e    l   o 0,5 0,50    h   w 0   o    l    B 14 15

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D  A

0,85

B

0,71 0,38 C

16 17 18 19

0,28 20

21

22

  23

0,56 0,50 0,27 0,23 24 25

Temperature [°C] A Mineral oil B Mineral oil with additives C Emulsion D Rapeseed oil

Surfaces produced using mineral-oil-based or vegetable-oil-based release agents evince considerable differences in terms of surface voidage. Even at low temperatures, the voidage figures achievable when a mineral oil with additive or an aqueous solution is used are acceptable. Under these circumstances the temperature-related fluctuation bandwidth of surface voidage is considerably narrower. Conclusion: In the case of oil-based release agents in particular, viscosity influences de-aeration of the peripheral zone. High release-agent viscosity produces stronger adhesion forces along the formwork sheeting and this tends to trap the air bubbles that form voids at the sheeting.

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7 The Formwork Experts

Doka Knowledge Transfer Fair-faced concrete - Low-void concrete surfaces

Interaction between formwork sheeting and release agent The choice of release agent has a significant effect on the surface voidage of the finished concrete, particularly with non-absorbent, plastic-coated formwork sheeting (Xlife) but also in the case of slightly absorbent, phenolic-resin-coated sheeting (Dokaplex), depending on the age of the sheeting in terms of number of previous use cycles. The inherent absorbency of other slightly absorbent sheeting (3-SO) and strongly absorbent wooden-board shuttering compensates to a large extent for the effect of the release agent. When oils and oils with additives are used this leads to low surface voidage. Influence of the season of the year in conjunction with non-absorbent and very weakly absorbent formwork sheeting (Xlife, Dokaplex) ●

Summer:

 Aqueous release-agent emulsions are best suited for fair-faced concrete applications. On account of their low viscosity, mineral oils with additives (applied in small quantities only) are also used for work in summer temperatures. ●

Winter:

Once ambient temperatures dip below < 10 °C, fairfaced concrete to standards compatible with high requirements classes can be produced only subject to certain restrictions. In winter, mineral oils without additives in particular thicken to high viscosity and thus cause severe surface voidage. In the case of mineral oils with additives, it is important to ensure that they evince low viscosities even in winter-usage conditions (special additives, viscosity regulators).

These conditions permit good concrete de-aeration along the formwork sheeting. Influence of the season of the year in conjunction with weakly absorbent (3-SO three-play) and absorbent formwork sheeting (wooden boards) ●

Summer:

Mineral oils with additives are used for absorbent formwork sheeting (wooden-board shuttering, untreated plywood, chipboard products). Aqueous emulsion release agents are also used, subject to certain restrictions (3-SO). When temperatures are high and the formwork sheeting is absorbent, if the flash time is long than a day it is important to ensure that the emulsion is not absorbed into the sheeting. ●

Winter:

When mineral oils with additives are used they should evince no significant differences in viscosity between summer and winter conditions. Unconditioned mineral oils with additives should not be used in winter. They become highly viscose and obstruct de-aeration along the face of the sheeting. A suitable antifreeze agent has to be admixed to emulsions. If fair-faced concrete requirements are high it is advisable to conduct on-site tests with trial coupons in order to match up formwork sheeting, release agent and concrete.

Overview: formwork sheeting, seasonal conditions and suitable release agents

Release agent types

Formwork sheeting and climatic conditions Summery ambient temperatures Wintery ambient temperatures +15 to +35°C -4 to +14°C WoodenWoodenXlife Dokaplex 3-SO board Xlife Dokaplex 3-SO board formwork formwork

Mineral oil or vegetable oil without additives Spray on and wipe down

Mineral oil or vegetable oil and additives Spray on and wipe down Doka-Trenn

 Aqueous emulsions usable down to ambient temperatures of +5°C Spray on

 Aqueous emulsions usable down to ambient temperatures of -4°C Spray on Doka-OptiX

Suitability Very good Good Poor 

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999453102 - 02/2012 The Formwork Experts

Doka Knowledge Transfer Fair-faced concrete - Low-void concrete surfaces

creting can commence once adequate flash time has expired. The following factors influence the flash time of emulsions: ● Quantity applied ● Temperature ● Local relative humidity on site ●  Absorbency of the formwork sheeting  An emulsion's flash time is always stated on its product data sheet.  All the formwork elements of a concreting section should be sprayed with release agent at the same time. Once the release agent ahs been applied, protect the sheeting against rain, wind and direct sunlight. Concreting can commence 4-6 hours (empirical value) after application of the release agent.

Application and use of release agents Once the release agent has been sprayed on it is important to wipe off the excess with a clean cloth; this applies in the case of oils in particular. The release agent should be applied sparingly and spread uniformly over the entire surface. Use the fingertip touch-test method of checking release-agent application. Fingertip touch-test

Release agent correctly applied. Too much release agent used.

The carrier medium of aqueous release-agent emulsions is water and it is important to allow the emulsion enough time for the excess water to flash off. Evaporation of the water means that it is not necessary to remove/wipe off the excess release agent. The emulsion's flash time will inevitably be longer in the cooler seasons of the year and in humid conditions. ● Summer: approx. 15 to 30 minutes (according to data sheet). ● Winter: allow for temperature and relative humidity.  Aqueous release-agent emulsions generally form a watery, whitish film after being sprayed onto the surface. A thin, colourless, transparent film forms within the flash time or in the process of demulsification. ConEffect of quantity of release agent applied on proportion of surface voids         8          6    ,           2

3 2,5 2 1,5 1

        5          8    ,           0 

        7         7   ,           1

        9          5    ,           1

        5          5    ,           1

        3          1   ,           1

        8          8    ,           0 

        1         7   ,           0 

        8          3    ,           0 

0,5

        3          5    ,   0 

        6          2   ,           0 

        1         2   ,           0 

        7         1   ,           0 

        8          2   ,           0 

0 B

 A

 

C

D

E

F

94531-802

G

A Vegetable oil B Mineral oil C Mineral oil + additives D Mineral oil + additives E Emulsion F Emulsion G Mineral oil + solvent

Small quantity applied Large quantity applied

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9 The Formwork Experts

Doka Knowledge Transfer Fair-faced concrete - Low-void concrete surfaces

Concrete Concrete to EN 206-1 Properties, production and conformity of the concrete are regulated by the terms and conditions laid down in EN 206-1 (framework standard). The national standard for Germany is DIN 1045-2 and the corresponding Austrian standard is ÖN B4710-1. Concrete has to satisfy engineering and usage-related requirements. Concrete is graded by type and exposure class (environment class), again depending on requirements. See the "Doka Knowledge Transfer" Lotus Notes tile and the detailed information on "Concrete". National codes for fair-faced concrete: ● Germany: Merkblatt Sichtbeton (Bulletin for Fairfaced Concrete), August 2004, DBV and BDZ. ●  Austria: "Sichtbeton - Geschalte Betonflächen" (Fairfaced Concrete - Formed Concrete Surfaces), ÖVBB guideline.  As regards its composition and working, fair-faced concrete is required to meet the technical requirements set down in EN 206-1.

Binder  The term 'binder' refers to the combination of cement with hydraulically active aggregates (cinder sand, fly ash). The proportions by volume and the use of these hydraulically active aggregates are regulated by the national implementations of EN 206-1. The effects on the concrete's working, setting and strength development depend largely on the binder's composition and fineness of grinding. The workability of the concrete is a very important aspect as regards the production of fair-faced concrete finishes: ● Stickiness, viscosity ● De-aeration propensity ● Compactability Binder properties Binder  Fineness of grind- High Coarse ing (> Blaine 4500 cm2/g) (> Blaine 3500 cm 2/g) Reduced (CEM II/A max. 80 % clinker, CEM Proportion of High (CEM I 42.5 / II/B max. 60 % clinker, clinker  95% prop. of clinker) CEM III/A max. 35 % clinker) Water need High Low

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Effect of binder on concrete: ● With cements and clinker, fineness of grinding increases in relation to strength class. The finer the cement stone the larger its specific surface, and this in turn increases its water need and accelerates the hydrothermal reaction. ● The cements used for ready-mix concrete are generally those assignable to the strength classes 32.5 and 42.5. The most commonly used cement grades are CEM II products (CEM II/A max. 20 %, CEM II/B max. 35 % aggregates). ● Water content alone does not suffice to ensure requirements-compliant consistency. Consequently, as a general rule concrete of all grades (exception: XC3) has to be mixed with a liquefier/plasticiser in order to obtain workable consistencies. ● Modern PCE liquefiers are polycarboxylate-based and enable the concrete to achieve the specified consistency and adequate working time despite a low water content. ● The liquefier increases the stickiness of the fresh concrete and this in turn hampers de-aeration along the formwork sheeting. ● The higher the binder's water need or the lower the w/b ratio, the higher the proportion of liquefier required. The quantity of liquefier, in turn, increases the stickiness/viscosity of the concrete. ● Binders with low water need (optimum workability, low tendency for blowholes to form) are best for summer conditions. In winter the cements used are of higher degrees of fineness and the proportions of clinker are higher, because this helps prevent bleeds and demixing. Suitability of cements for fair-faced concreting in terms of stability and surface voidage Binder / cement CEM I 32.5 CEM II/A 32.5 CEM II/B 32.5 CEM II/A 42.5 CEM II/B 42.5 CEM III/A 32.5

Surface voids and stability Summer Winter   Pores Stability Stability Stability Pores Pores Stability

Suitability Very good Good Poor 

999453102 - 02/2012 The Formwork Experts

Doka Knowledge Transfer Fair-faced concrete - Low-void concrete surfaces

w/b ratio See the "Doka Knowledge Transfer" Lotus Notes tile and the detailed information on "Concrete". Effect of water-to-binder ratio and compaction time Compaction time: 30 seconds Compaction time: 60 seconds

   t   s   u    d    l   a   r   e   n    i   m    %    0    1    h    t    i   w    N    5  .    2    3    A    I    I    I    M    E    C

1,34 %

1,20 %

 

94531-807

Concrete mixed to meet high requirements in terms of strength and durability generally has a low water-tobinder ratio. Regarding fair-faced concrete applications, the rule of thumb is:

The lower the w/b ratio, the higher the influence of the cement on the finished fair-faced concrete product.

Effect of w/b ratio on concrete: ● If the w/b ratio is low a higher proportion of liquefier is needed (mixed concrete is stickier/more viscous). ● Concrete with a w/b ratio ≥ 0.5 generally evinces more favourable characteristics with regard to deaeration along the face of the formwork sheeting. ● Some 80 % of fair-faced concrete applications involve concretes with a w/b ratio ≥ 0.5. ● Concretes with w/b ratios < 0.5 are generally frostproof and de-icing saltproof concretes and concretes for wastewater treatment facilities and high-performance concrete. Effects of the w/b ratio can be countered by more compaction work and selection of an optimised release agent.

94531-808

w/b ratio = 0.45

Compaction time: 30 seconds Compaction time: 60 seconds

   t   s   u    d    l   a   r   e   n    i   m    %    0    1    h    t    i   w    N    5  .    2    3    A    I    I    I    M    E    C

0,65 %

0,40 %

94531-809

94531-810

w/b ratio = 0.50

Surface voidage as a function of w/b ratio and grade of concrete Code (AUS) B1 B2 B3 B4 B5 B6 B7

Environment classes covered XC3 XC3/XD2/XF1/ XA1L/SB XC3/XD2/XF3/XA1L/SB XC4/XD2/XF1/XAL1/SB XC4/XD2/XF2/XAL1/SB XC4/XD2/XF3/XA2L/XA2T/SB XC4/XD2/XF3/XA2L/XA2T/SB

Maximum w/b ratio(AUS) 0,60 0,55 0,55 0,50 0,50 0,45 0,45

Maximum w/b Blowhole propensity, ratio(GER) surface voidage 0,65 Low 0,50 Low 0,50 Low 0,50 Medium 0,50 Medium 0,50 Elevated 0,45 Elevated

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11 The Formwork Experts

Doka Knowledge Transfer Fair-faced concrete - Low-void concrete surfaces

Chemical admixtures  Additives are liquid or powder substances admixed in the course of production to control the properties of the concrete in its fresh and set states. The proportion of additives is generally in the range between 0.1 and 0.3 % by mass of binder. See the "Doka Knowledge Transfer" Lotus Notes tile and the detailed information on "Concrete". Important additives: ● The additives most commonly used in the production of fair-faced concrete are Liquefiers. Depending on their composition, liquefiers control the consistency and the workable time of the concrete. Liquefiers that make the concrete sticky have a negative effect on concrete de-aeration along the formwork sheeting. ● The air-entraining admixture is another important additive. - It is used in the production of concretes that are resistant to frost, de-icing salt and chemicals. It causes the formation of microvoids of air in the fresh concrete and these tiny cavities allow for expansion when frost acts on the concrete. - If low-fines aggregate is used, the air-entraining admixture can help stabilise the concrete mix to a certain extent. - The need for liquefier can also be reduced and this improves the workability of the concrete. ●  A defoamer  can be used for special fair-faced concrete applications (slender, complicated structural elements). Defoamers destroy air voids in the fresh concrete. These products are best not used for concretes that are intended to have a high proportion of voidage. Defoaming products are very costly and meticulous care has to be exercised in matching them to the other ingredients in the concrete recipe as otherwise there is a danger of undesirable sideeffects occurring. ● Stabilisers and viscosity regulators are used in easily compacted concretes (consistency classes F5, F6) to prevent demixing.

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Temperature of the fresh concrete and the ambient temperature The various standards lay down limits for fresh-concrete temperature and ambient temperature. Compliance with temperature limits is highly desirable for all fair-faced concrete applications subject to high requirements. Bleeding, demixing and clouding can all become more severe if these limits are not met in winter conditions. Excessively high temperatures in summer lead to premature stiffening and setting (lays, gravel pockets). Temperature ranges for fair-faced concrete as a function of quality  Ambt -5 °C 0 °C 5 °C 10 °C 15 °C 20 °C 25 °C 30 °C 35 °C . FCT -5 °C 0 °C 5 °C 10 °C 15 °C 20 °C 25 °C 30 °C 35 °C  Ambt ... Ambient temperature FCT ... Fresh-concrete temperature Fair-faced concrete High requirements - structural engineering Low requirements Infrastructure civil engineering Not possible to obtain reliable results in production of fairfaced concrete

Fair-faced concrete classes Germany Austria SB 4, SB 3

SB3, SB2

SB 2, SB 1

SB1

999453102 - 02/2012 The Formwork Experts

Doka Knowledge Transfer Fair-faced concrete - Low-void concrete surfaces

Consistency Invariably, consistency has to be adapted to suit the working of the concrete. F45/F3 is generally the lowest consistency allowable for fair-faced concrete. Consistencies for summer use must invariably be ≥ F52/F4 in order to ensure workability. In winter the consistency range is lower than summer, because this helps prevent bleeds and demixing. Consistency ranges of fresh concrete Slump Consistency range Class (ÖNORM 4710-1 /EN206*) Very stiff Stiff - / F1 Plastic F38 / F2 Soft F45 / F3 Very soft F52 / F4 Flowable F59 / F5 Very flowable F66 / F6 Extremely flowable F73 / -

Spread Slump [mm] 350 - 410 420 - 480 490 - 550 560 - 620 630 - 690 700 - 760

Class

Spread [mm]

S1 S2 S3 S4 S5

10-40 50-90 100-150 160-210 ³ 220

*F1-F6: Designations in Germany

See the "Doka Knowledge Transfer" Lotus Notes tile and the detailed information on "Concrete".

Aggregate  Aggregates are usually natural products of degradation processes. Properties and effects on fresh and set concrete: ● Petrographic (relating to stone) properties ● Chemical properties ● Screen line ● Grain shape - Round grain - Angular grain Consequently, it is not possible to formulate generalities with regard to the use of aggregates.  As a basic recommendation, the meal content of round grain should be about 400 kg/m3. The value is generally higher for angular grain. The specifics of choice and use of aggregates are regulated by EN 206-1 and its various national implementations (in Austria ÖNORM B4710-1, in Germany DIN 1045-2). See the "Doka Knowledge Transfer" Lotus Notes tile and the detailed information on "Concrete".

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13 The Formwork Experts

Doka Knowledge Transfer Fair-faced concrete - Low-void concrete surfaces

Usage on site Placement of the concrete

Stripping out and post-treatment

Concrete is generally played with the aid of crane buckets or concrete pumps. Rules for fair-faced concrete quality: ● Keep the drop height as short as possible (best of all is flush with surface, drop 0.00 m). ● Do not use vibrators to spread the concrete inside the formwork. ● Fill the formwork from several different points: the number of filling points increases with the size of the structural element. ● The maximum depth per layer of fill is 50 cm. When pouring self-compacting concrete (SCC), keep the drop height in the formwork low. Also make sure that the concrete can flow freely enough to de-aerate. If flow distances are not long enough surface voidage will inevitably increase.

Fair-faced concrete should be stripped out of the formwork as soon as technically possible, depending on the strength and exposure classifications. Post-treatment, in turn, is subject to the stipulations laid down in the applicable standards (Austria's ÖNORM B4710-1, Gemany's DIN 1045-2, or equivalent). Fair-faced concrete subject to high requirements has to be protected by a non-contacting membrane or by the formwork eased back 5 -10 cm. The formwork is covered at the top of the wall. Every effort should be made to prevent a flow of air along the face of the concrete. Contact between the concrete and the membrane or the formwork sheeting can result in blackening of the face if relative humidity is high. Light drying of the outermost edges of the concrete prevents discolouration of this nature. In situations in which aesthetic requirements are high it is not advisable to apply a post-treatment spray, because uniformity of surface colour is generally a stipulation.

Compacting The process of compaction must be state of the art.  Adapt immersion pitch and diameter of the vibrator poker to suit the thickness of the structural element. Signs of good compaction: ● Only isolated compaction voids rising. ● There is no further change in the sound made by the vibrator poker. ● Fine mortar blanks out the surface. ● The concrete stops settling. The immediate stitching of two successive lays is a very important aspect in the placement of fair-faced concrete. Post-compaction is particularly advisable for the highest lays, approaching the top of the wall. This helps prevent the accumulation of voids that can otherwise occur. Post-compaction must cease before the concrete starts to set. Another important point to bear in mind when compacting is to ensure that the poker does not touch the formwork sheeting or the reinforcing bars. Make sure that the concrete does not demix, because this leads to bleeding and separation problems. The outcome is that excess water and fines accumulate at the face of the formwork sheeting, causing the marbling effect that disfigures the surface of the concrete. The following factors reduce the effectiveness of the vibrator poker: ● Low water content ● High liquefier content ● Use of PCE products (polycarboxylate ether) The concrete becomes stickier. Under these circumstances reduce the pitch between poker immersion points and increase compaction time.

Blackening on the surface of the set concrete

94531-805

Protecting fair-faced concrete The fair-faced concrete surfaces must be suitably protected against damage until the structure has been accepted by the project owner.

See the "Doka Knowledge Transfer" Lotus Notes tile and the detailed information on "Concrete".

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999453102 - 02/2012 The Formwork Experts

Doka Knowledge Transfer Fair-faced concrete - Low-void concrete surfaces

Annex References Literature: ● "Richtlinie Sichtbeton -Geschalte Betonflächen" (Fair-faced Concrete - Formed Concrete Surfaces), Österreichische Vereinigung für Beton- und Betontechnik, 2009, printed by: F. Csöngei GmbH, Vienna,  Austria ● "Merkblatt Sichtbeton" (Bulletin for Fair-faced Concrete), Deutscher Beton- und Bautechnik-Verein E.V./Bundesverband der deutschen Zementindustrie E.V., DBV and BDZ (publishers), 2004 ● "Untersuchung relevanter Parameter zur Optimierung von Sichtbetonflächen" (Investigation into relevant parameters for the optimisation of fair-faced concrete surfaces), dissertation by Alexander Reinisch, Leopold-Franzens-Universität Innsbruck, 2007 ● "Untersuchungen der chemisch-physikalischen Wechselwirkungen zwischen Frischbeton, Schalhaut und Trennmittel" (Investigations into the physiochemical interactions between fresh concrete, formwork sheeting and release agent), Hillemeier B., Herr R., Schubert K, Kannenberg M., Fachtagung "Sichtbeton - Forschung und Praxis", December 2006, Düsseldorf  ● "Untersuchungen zu Einflussfaktoren bei der Sichtbetonherstellung" (Investigations into factors influencing the production of fair-faced concrete), Alexander Reinisch, Tiefbau 3/2008, pp. 147-150 ● "Sichtbetonbauwerke - Besonderheiten für Planung und Ausführung nach aktuellem Regelwerk" (Fairfaced concrete structures, specifics for planning and implementation as per the current code), T. Freimann, Georg-Simon-Ohm Hochschule Nurnberg, 2008

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