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Background Knowledge

Ingredients of Nanodur UHPC

What is Special about UHPC?

UHPC is a cementitious concrete with very high strength, impermeability and durability. In contrast to normal concrete, the pore content of the cement paste is significantly reduced. In Germany, a concrete up to a strength of C50/60 is referred to as 'ordinary concrete' and up to a strength of C100/115 as 'high-strength concrete'. Above this, it is common to name it  Ultra-High Performance Concrete.

What is the Secret Behind the Recipe of UHPC?

To achieve the densest possible packing, two measures are combined. On the one hand, superplasticizers based on PCE (Polycarboxylatether) are used to achieve a low water/binder ratio of around 0.15 tu 0.25. On the other hand, the particle sizes of the constituents of the cement paste are combined to form a grading curve with dense packing. To fill the gaps between the cement particles, reactive silica fume, metakaolins or particularly finely ground slag (super GGBS) are used. Above the cement particles, grinded silica sand or other stone flour are used to optimize the grading curve.

Is UHPC Difficult to Mix?

Because of the low water content, depending on the superplasticizer, the mixtures can be very sticky and the engine of the mixer must be powerful. Fibers intensify the challenge. With a standard mixer, you only fill it to half of the nominal volume. Pan mixers, ring trough mixers or similar compulsory mixers are best suited. Twin-shaft mixers or rotary drum mixers present special challenges.

Designations and Abbreviations to High Strength Concretes

Depending on the field of application or special components of the compounds, many abbreviations have developed, which are explained below.

  • UHSC „Ultra high strength concrete“

  • UHPFRC „Ultra high performance fiber reinforced concrete“

  • UHPdC „Ultra high performance ductile concrete“

  • DFRCC „Ductile fiber reinforced cementitious composite“

  • SHCC „Strain hardening cementitious composite“

  • ECC „Engineered cementitious composite“

  • UHP-HFRC „Ultra high performance hybrid fibre reinforced concrete“

  • HPFRCC „High performance fiber reinforced cementitious composites“

  • RPC „Reactive powder concrete“

  • UHFB „ultrahochfester Beton“ (German)

  • UHFB „Ultra-Hochleistungs-Faserbeton“ (Swiss)

  • UHFB „ultrahochfester-Faserverbund-Baustoff“ (Swiss)

  • UHLB „Ultra-Hochleistungsbeton“ (German)

  • BFUB „Béton fibré à ultra-hautes performances“ (French)

  • BPR „Beton de Poudres Réactives“ (French)

Codes for UHPFRC / BFUB / UHFB in Europe

  • NF P 18-470 Bétons fibrés à ultra-hautes performances – Spécification, performance, production et conformité, AFNOR, Paris 2016

  • NF P 18-710 Calcul des structures en béton – Règles spécifiques pour les bétons fibrés à ultra-hautes performances (BFUB), AFNOR Paris, 2016

  • NF-P 18-451 Bétons – Exécution des structures en béton – Régles spécifiques pour les BFUB

  • SIA 2052 „Ultra-Hochleistungs-Faserbeton (UHFB) – Baustoffe, Bemessung und Ausführung“

What is Dyckerhoff GmbH?

Dyckerhoff is a cement producer with 7 cement plants and 3 grinding plants and more than 2,000 employees within Germany. Since 2004 Dyckerhoff is part of the international operating Buzzi Unicem Group.

What is Durcrete GmbH?

Durcrete is an engineering and trading company dealing with Ultra High Performance Concrete -UHPC. It delivers binders as well as ready made products and gives consultancy services.

Who is Bernhard Sagmeister?

Dr.-Ing. habil Bernhard Sagmeister is a German Civil Engineer. He studied in Munich and wrote his PHD-Thesis at the Technical University of Darmstadt. Giving lectures about UHPC at the Technical University of Kaiserslautern, he is founder, owner and managing director of durcrete GmbH.