Grouting mortar

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Grouting mortars according to the DAfStb guideline are high-strength, cement-bound and non-shrinking mortars , which are already exceptionally flowable in the top class with a solid-water ratio (in parts by weight) of 10 to 1. The grouting mortar was invented in 1960 by Arnfried Pagel .

Grouting mortar should achieve and demonstrate the following technical values:

  • The flowability standard f3 : Measured in the flow channel, the grouting mortar in the 1-liter funnel must exceed a flow dimension of 75 cm.
  • The compressive strength in early strength class A must be greater than 40 N / mm² after 24 hours.
  • The compressive strength in the compressive strength class for concrete C100 / 115 transferred to grouting mortar should be equivalent or higher after 91 days.
  • The volumization must be more than 0.1% after 24 hours.
  • The shrinkage must be less than 0.08% in the highest class SK (VM-1).
  • The grain size of the grouting mortar must not be more than 4 mm.
  • The exposure classes (requirements for the maximum water-cement ratio, compressive strength, cement content and pore content) for hardened concrete should be met without objection.
  • The following highest classes should be achieved:
    • XS3 in tidal areas, splash water and spray mist areas such as port facilities and components that are constantly under water
    • XA3 in chemically aggressive environments such as industrial wastewater systems, fermentation silos, cooling towers and flue gas discharges
    • XM3 for very heavy wear and tear, load-bearing or stiffening industrial floors with loads from forklifts with steel roller tires or from being driven on by tracked vehicles and in hydraulic structures in waters subject to loading

Grouting mortars were brought onto the market around the same time in the USA and Germany in the early 1960s. In the USA, Master Builders in Cleveland (Ohio) was initially the world market leader, but followed the principle of rusting to overcome shrinkage. Provided help a chloride - catalyst , the finely ground iron was aufrosten flash and thereby generated even expansion. This approach turned out to be wrong, since a rust-forming attack on cast and non-cast iron parts was inevitable due to ion migration, which ultimately caused severe damage and led to the material's self-destruction. Around the same time, Arnfried Pagel and his company Arnfried Pagel pers., Ing Bautechnische Produkte und Beratung brought a completely differently conceived grouting mortar onto the market. The volumization was effected by broken down mineral additives, which allowed a very precise dosage and guaranteed volumization in tenths of a percent increment. The most common volumization value was 0.4% to 1%.

This invention, based on the principle of "power transmission through force-fit", is quickly gaining acceptance worldwide and is the only variant produced by Pagel and other companies today.

Grouting mortar was included in the DAfStb guidelines of the German Exclusion for Reinforced Concrete.

This guideline became necessary because the technical values, documented by state test certificates for the most relevant loads, were included in complex power transmission calculations (measurement of the adhesive tension). Since grouting mortar was used practically everywhere, state supervision, certification, Ü-mark and supervision became necessary.

The decisive advantage of the new grouting mortar is that the forces in the machine are diverted directly into the foundation and not, as in the past, via the anchoring. The Krupp and Thyssen companies were interested in Pagel's invention. The power transmission measurements of these two companies confirmed that the forces were derived over the entire encapsulation of the machine. A decrease in the susceptibility to repairs in the bearings and on the anchor fixings of 60–80% was determined. In addition, there was a significantly longer production time, significantly lower production downtime and thus a large cost saving.

After these measurement results and the acquisition of state test certificates, the triumphant advance of this mortar could no longer be stopped. The mortar then found its way into the construction plans of machine and turbine plants such as Siemens , BBC and AEG . These companies required proof of how grouting mortar behaves under pressure and simultaneous vibration. Previously, all mortar was destroyed in this claim. The grouting mortar passed this test without any deviation from the technical maximum values, on the contrary: the compressive strength increased due to the vibration compaction and the capillary pressure of the volumization.

The grouting mortar has become indispensable in precast construction, as large construction elements can be introduced in a force-transmitting manner via the joint grouting. An adhesion test was required here by large construction companies and test engineers. In the past, reinforcement overlaps of one meter were common. In pull-out tests from the grouting mortar, all reinforcement bars with a diameter of 25 mm and an insertion depth of only 15 cm achieved a breaking load of around 361  kN .

With the ever-increasing proportion of epoxy resins, Pagel developed another non-shrinking epoxy resin grouting mortar EV 1. This mortar is mainly used in the water, food and chemical sectors because of its largely chemical resistance.

literature

  • Frank Fingerloos, Johann-Dietrich Wörner: Concrete Calendar 2015. Focus on building in existing bridges, Ernst & Sohn Verlag, Berlin 2015, ISBN 978-3-433-03073-8 .
  • Michael Raupach, Jeanette Orlowsky: Preservation of concrete structures. Building materials and their properties, 1st edition, Vieweg + Teubner, Wiesbaden 2008, ISBN 978-3-8351-0120-3 .

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