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Tailor Made Concrete Structures – Walraven & Stoelhorst (eds)© 2008 Taylor & Francis Group, London, ISBN 978-0-415-47535-8

Properties and applications of DUCON® A micro-reinforcedultra-high-performance concrete

Jens Schneider & Jörg ReymendtFrankfurt University of Applied Sciences, Department of Architecture and Civil Engineering,Frankfurt, Germany

ABSTRACT: The main advantage of DUCON (DUctile CONcrete), a patented 3-D micro-reinforced, self-compacting Ultra High Performance Concrete, is its ductility in combination with high compressive and flexuralstrength. This paper describes the properties and recent applications of DUCON. The material proved to haveexceptional advantages as explosion resistant and bullet/fragment proof material. Explosion tests performedshowed high energy absorption and ductility, i.e. no failure and no fragment projectiles. Special sniper projectileswhich easily penetrate standard reinforced concrete can be stopped by DUCON panels. The main field ofapplications and projects realized so far are therefore the protection of critical infrastructure, such as military andpublic buildings, embassies, power plants, banks and data centers and ammunition storage tanks. Here, DUCONis used in new structures or for retro-fitting of existing structures in slabs and walls (fragmentation protection),for column protection, protective elements, etc. Moreover, other engineering and architectural projects realizedsuch as industrial overlay, retro-fitting of columns for earthquake protection, slim façade panels and interiordesign elements show the great variety in applications of the material.

1 MATERIAL

1.1 Composition and material characteristics

DUCON stands for DUctile CONcrete and representsthe combination of a high-performance or ultra-high-performance concrete and a micro-reinforcement fromsteel wire meshes (Fig. 1), developed by Hauser.The micro-reinforcement is uniformly distributed allover the cross section which results in a homoge-nous composition of the composite material (Hauser1999, Hauser & Wörner 1999). It consists of multiplelayers of meshes with variable mesh width (between

Figure 1. Self-compacting high-strength concrete +micro-reinforcement.

6 mm and 35 mm) which are 3-dimensionally con-nected. Table 1 shows the most important materialcharacteristics.

1.2 Production

Production is based on the placement of the pre-fabricated micro-reinforcement and the infiltration ofthe concrete slurry (Fig. 2).

Between 1 Vol.-% and 10 Vol.-% of micro-reinforcement are embedded, typically, 6 Vol.-%.

Due to the fine mesh size of the micro-reinforcement, the crack width can be reduced tovalues of w < 0,1 mm which qualifies DUCON as

Table 1. Material characteristics.

Type Value

Compressive strength 90–180 N/mm2 (cube)Flexural strength 16–75 N/mm2

Tensile strength 9–20 N/mm2

Shear strength 3–16 N/mm2

Modulus of elasticity >35,000 N/mm2

Thickness ≥10 mm–500 mmDuctility factor >10

399

Figure 2. Slurry infiltration process.

Figure 3. Stress-deflection diagram for three differentadjustmentsA, B, C of DUCON in comparison with standardconcrete and a typical fiber-reinforced concrete.

impervious material. Thus, DUCON can be executedwith a small concrete cover of a few millimeterscompared to 20 to 50 mm of standard reinforcedconcrete.

1.3 Flexural strength and ductility

One major benefit of DUCON is that the mate-rial performance is programmable. Various set-upsand qualities of the micro-reinforcement (e.g. steelcharacteristics) allow the adaption of the material per-formance to the specific application. Figure 3 showsa stress-deflection diagram from flexural bendingstrength tests (Fig. 4) with three different possibleadjustments A, B, C in comparison with standard con-crete and typical fiber-reinforced concrete. Note thatthe curves for standard concrete (grey) and fiber-reinforced concrete (blue) are shifted horizontally fora better legibility.

Besides having high compressive and flexuralstrength, the properties can thus be adjusted to achievean extremely ductile material.The ductility and its highstrength are the key characteristics for high energyabsorption of high speed dynamics and dynamics incombination with large deformations.

Figure 4. Four-Point-Bending-Test of a DUCON member,thickness 25 mm.

Flexural strength DUCON ductile Stress-Strain-Curve

0

10

20

30

40

50

60

70

80

Fle

xura

l Str

ess

[N

/mm

²]

K6

DUCON

5%Deflection [Strain]

ECC

Standard Concrete

Figure 5. Comparison of DUCON (blue) with an Engi-neered Cementitious Material (ECC, green) and standardconcrete (black).

Compared to other ductile materials DUCON pro-vides a high load bearing capacity at the same time(Fig. 4). The specimen as shown in Fig. 4 had a maxi-mum deflection at a failure of 75 mm at 540 mm span.These characteristics are required for building protec-tion for example against explosion and earthquake.Figure 5 shows a comparison of the flexural behaviorof DUCON in comparison with a typical EngineeredCementitious Composite (ECC, Wang & Li 2006) anda standard concrete.

Whereas “ECC has approximately half the flexu-ral strength of Ductal (another ultra-high-performanceconcrete) but 20 times its tensile ductility” (Smock,2007), DUCON exhibits even more than twice the ten-sile ductility of ECC and more than 4 times its flexuralstrength.

2 DYNAMIC PROPERTIES

2.1 Blast resistance

Figures 6 and 7 demonstrate the resistance of DUCONagainst close range and contact charges compared toreinforced concrete (RFC) at the same thickness of

400

RFCRFCRFCRFC

Figure 6. Reinforced concrete fails under contact charge.Full penetration + fragment projectiles.

DUCONDUCONDUCONDUCON

Figure 7. DUCON remains stable, no penetration nor frag-ment projectiles, 85% of the cross section stays intact.

Figure 8. Finite-element simulation of DUCON under con-tact charge load.

150 mm (RTL TV broadcasting, 2004). The reinforcedconcrete failed, the blast wave penetrated the paneland in addition created fragment projectiles. DUCONresisted the blast test and no penetration or fragmentscould be observed.

Several blast tests of the Fraunhofer Institute andfor the US Military (Schuler & Mayrhofer 2004,Schuler & Mayrhofer 2007, Marchand 2007) provedthat the blast resistance of DUCON is at least twice asgood as of ordinary reinforced concrete, which meansit can be executed at half the thickness and in additionit does not spall.

The 3-dimensional micro-reinforcement keeps thestructural integrity of the concrete and avoids spallingand fragment projectiles.

The material properties of DUCON have beenrecently implemented into a finite element code forhigh-speed dynamics (Fig. 8, Gebbeken & Greulich,2006).

Figure 9. DUCON panel, thickness 100 mm, resists a armorpiercing Wolfram-Carbit Penetrator at a speed of 840 m/s.

2.2 Ballistic resistance

According to the blast resistance DUCON proveda comparable performance in ballistic resistance. Itreaches the resistance of reinforced concrete withless than 50% of the thickness. Moreover, the special3-dimensional micro-reinforcement allows a struc-tural integrity of the concrete and avoids spalling.

Figure 9 shows that a 100 mm thick DUCON panelabsorbed armor piercing bullet (Wolfram-Carbit pen-etrator at a speed of 840 m/s) while RFC needed to be24 cm. Bullet tests resulted in a PM7 (highest require-ment level of European code) for a thickness of only80 mm.

Further Military test series (Marchand 2007) provedthat a 10 cm DUCON-panel also resists high velocityfragments of propeller drilled weapons, like Mortarsin combination with explosion.

3 RECENT APPLICATIONS

3.1 Fragmentation protection for blast loading

Figure 10 shows an application of a DUCON layer(thickness 15 mm) acting as an integrated “safety-net”on the bottom of a reinforced concrete slab (thickness300 mm). The tests performed proved the effective-ness of DUCON to remain the structural integrity ofthe slab under blast loading. This application has beenused several times to protect the server room of highsecurity data centers in Europe. It was also used forthe concrete walls.

3.2 Blast protection wall and blast protectionfacade

In these applications, DUCON has been used asprotective walls and secondary facades in front ofendangered buildings. Walls have a typical thicknessof 100 mm to 250 mm, façade elements a typical

401

DDUUCCOONN

RRFFCC

Figure 10. DUCON panel, thickness 15 mm, acts as an inte-grated “safety-net” on the bottom of a reinforced concreteslab.

Figure 11. DUCON wall, thickness 250 mm, acts as protec-tive element in front of an embassy.

thickness of 40 mm to 150 mm. The DUCON panelsare prefabricated elements and can be easily trans-ported and installed. Figure 11 shows an embassy inEurope protected by a DUCON wall.

3.3 Blast protection columns

Here, two types of production have been applied; aretro-fitting of existing columns (Fig. 12) or tubecolumns made of DUCON used as integrated form-work (Fig. 13). They have been applied for earthquakeprotection (Zekaria 2001) and for blast protection(Schuler & Mayrhofer 2007).

3.4 Impervious and abrasive resistant overlays

Based on the high performance material characteristicsof DUCON, impermeability, durability, freeze-thawresistance and corrosion resistance in combinationwith crack control have been tested for the Inter-national Code Council (ICC) approval which wasobtained for the applications on the US market.

Figure 12. Retro-fitting of existing columns for earthquakeprotection.

Figure 13. DUCON tubes used as integrated formwork forreinforced concrete columns.

Figure 14. DUCON overlay, 25 mm, applied on an existingcracked concrete slab of a chemical plant.

These characteristics are well suited for applica-tions of thin impervious overlay on top of existing ordamaged flooring or concrete structures.

Figure 14 shows an application at a chemical plantwhere 7.500 m2 of damaged and cracked concrete

402

Figure 15. Entrance portal of DUCON, height 4,50 m, span4,50 m, thickness 80 mm to 100 mm.

slab could be quickly repaired by a 25 mm DUCONoverlay and a time- and cost consuming demoli-tion and reconstruction of the concrete could beavoided.

3.5 Architectural applications

Beside thin plates for tables, façade panels or countertops, recently also structural elements have been pro-duced. Figure 15 shows an application as an entranceportal, height 4,50 m, span 4,50 m with a thickness ofonly 80 mm to 100 mm. The portal was pre-fabricatedand installed on site.

Thin members of concrete for free-form appli-cations are another future possibility as the micro-reinforcement can be adapted to any shape by hand.

4 CONCLUSIONS

DUCON, a very ductile composite material of con-crete and steel, shows excellent material propertiesand a large spectrum of applications. Its high energyabsorption allows applications for blast and ballis-tic protection without fragmentation at approximatelyhalf the thickness of ordinary reinforced concrete.

Future applications and research should also con-sider the stability behavior of the material, e.g. forshells and thin membranes and should develop newconnections.

DUCON® = registered Trademark of DUCONGmbH.

REFERENCES

Blastow M. 2006. High performance product testing goesballistic, Concrete Products, 10/2007: 36–39.

Gebbeken, N. & Greulich, S. 2005. Expert opinion and struc-tural design of blast wall, Universität der Bundeswehr,report.

Gebbeken, N. & Greulich, S. 2006. Expert opinion on struc-tural design of a blast wall, Universität der Bundeswehr,report.

Hauser S. 1999. DUCON und SIMCON NEU ein innovativerHochleistungsbeton, PhD-thesis, Darmstadt University ofTechnology.

Hauser, S. & Wörner J.-D. 1999. DUCON ein innova-tiver Hochleistungsbeton Teil 1: Grundlagen. Beton- undStahlbetonbau, 2/1999: 66–75.

Hauser, S. & Wörner J.-D. 1999. DUCON ein innova-tiver Hochleistungsbeton Teil 2: Bemessung. Beton- undStahlbetonbau, 3/1999: 141–145.

Hauser, S. & Wörner J.-D. 1999. Hochleistungsfaserbeton,Materialeigenschaften und Anwendungen, In Festschriftzum 60. Geburtstag von Herrn Prof. Falkner, TUBraunschweig, 1999.

Hauser, S. & Wörner J.-D. 1999 DUCON, a durable overlay,Rilem HPFRCC International Symposium Mainz, May1999.

Hofmann, P. et al. 2007. Toughened throughout. Micro-reinforced concrete gets blast resistance as its first assign-ment, Concrete International 29(12).

Marchand, K. 2007. Ballistic and Blast Tests of DUCONPanles for Department of Defense at deployed operationbases (DOBs) Overhead Cover Applications. ProtectionEngineering Consultants, report, July 12th, 2007.

Miller, S. 2007. Explosion in blast resistant construction,Masonry Construction Journal, 10/2007: 1–5.

Reymendt, J. 2006. Instandsetzung von Betonbauteilen beimUmgang mit wassergefährdeten Stoffen. In: Dehn F.,Klaus Holschemacher, K., Tue, N.V. (eds). Sanierung undVerstärkung von Massivbauten. Bauwerk Verlag GmbH,Berlin.

RTL TV broadcasting 2004. Blast tests DUCON vs. RFCSeminar of THW and Firemen.

Schuler H. & Mayrhofer C. 2004. Stoßrohrprüfung von Plat-ten aus DUCON, Fraunhofer Ernst Mach Institute,August2004.

Schuler H. & Mayrhofer C. 2007. Untersuchung vonmikrobewehrten Betonstützen bei Explosionseinwirkun-gen, Fraunhofer Ernst Mach Institute, Report, June 2007.

Smock, D. 2007. Bendable Concrete Protects AgainstHurricanes. Reed Business Information, Reed Elsevier,November 11th, 2007.

Wang, S & Li, V.C. 2006. High-Early-Strength Engi-neered Cementitious Composites. ACI Material Journal,March–April 2006: 97–105.

Zekaria, A. 2001. Seismic retrofitting of reinforced concretecolumns using SIMCON jackets, PhD-thesis, DarmstadtUniversity of Technology.

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