underwater applications

8/13/2019 Underwater Applications

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Hilti Entwicklungsgesellschaft mbH

Bereich Befestigungstechnik

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Underwater applications with HIT-RE 500 intern

Hilti HIT-RE 500for

“Underwater Fastenings”

Hilt i HIT-RE 500

Hilti HIT-RE 500 Injection Adhesive for„ Underwater Fastenings“

General information:

Hilti HIT-RE 500 injection mortar shows good performance in wet or water-filled bore holes.Therefore several test series have been done to evaluate the performance of HIT-RE 500 in underwaterconditions down to 50m below see level.

The test program contained:- short-term pull-out test with 2 different anchor sizes and 2 different types of fastening

elements – threaded rods and rebars.

- long-term creep tests with threaded rods and rebars.

- simulation run in a pressure chamber down to 50m under water to check the handling andproper function of all system components of the HIT-RE 500 injection system – foil pack , jumbo cartridge, manual and pneumatic dispensers.

With the pressure chamber simulation run we have proven HIT-RE 500 foil pack system as well as jumbocartridge system will work properly at least down to 50m of underwater.

The short-term tests as well as long term creep tests show Hilti HIT-RE 500 injection adhesiveworks well if used for anchor fastenings underwater.

The HIT-RE 500 underwater system differs from the existing Hilti underwater system:HIT-RE 500 does not need an adhesive capsule in addition to the injection mortar .Just inject the mortar HIT-RE 500 in a hammer drilled, well cleaned bore hole and insert the fasteningelements threaded rods HAS, internally threaded sleeves HIS-N or rebars.

Addi tional advantages of HIT-RE 500 in underwater fastenings are:- Due to the unique mortar formulation with its low dispensing force at low mortar temperatures

and due to the unique foil pack system HIT-RE 500 can easily be used down to watertemperatures of 5°C / 40°F.

- Due to the long working/gel time of HIT-RE 500 underwater applications can be performed veryconvenient.

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The red colour of the mortar is a great advantage in case of contrast and visibility under thesequite difficult site conditions.

Tests in sweet water as well as in salty water show proper curing of HIT-RE 500 injection mortar, if themortar is used under recommended conditions described in this paper and in the “Instruction for use”,distributed with the product.

Fastenings made with HIT-RE 500 have been tested for water tightness up to 7 bar of water pressure.The tests proved that fastenings in concrete with HIT-RE 500 are as water tight as the concrete itself !







Hilti HIT-RE 500for


This procedure will inform you how threaded rods, internally threaded sleeves and reinforcing bars can bedesigned for and installed in underwater applications using Hilti HIT-RE 500 injection adhesive.

Corrosion aspect:Even if anchor design and installation is done properly the duration of the fastening will depend oncorrosion resistance of the metal fastening element.Therefore careful selection of the right steel quality for the fastening elements and/or corrosion protectionsare essential for the duration of the fastenings.Please refer also to Hilti’s “Corrosion Resistant Fastenings” brochure, edition 2000.

Setting procedure:

The quality of the fastening is mainly depending on the bond and keying between mortar and basematerial. Therefore drilling method, proper bore hole cleaning and correct mortar injection – from thebottom of the hole - is essential for the final fastening quality !

Due to the different setting conditions in underwater fastening compared to normal fastening the followingsetting procedure is specifically designed for underwater applications:

1. Drill bore hole.

Using pneumatic hammer drilling only

Diamond coring for underwater fastenings is not allowed !

2. Flush-out dust and debris out of the bore hole using water

3. Clean the bore hole using steel brush. Steel brush diametershould match quite well with the bore hole diameter (approx. 2till 5 mm larger than the bore hole diameter) to get a good cleaningquality. Move with the steel brush 5 times though the full bore holedepth.

4. Again flush the bore hole with water until the out-coming water isclear.







Hilti HIT-RE 500for


5. Insert foil pack into holder

6. Screw on the mixer/mixing nozzle to the foil pack or cartridge

7. Insert foil pack holder assembly into dispenser and start mortardispensing

Insert jumbo cartridge into pneumatic dispenser and start mortardispensing

8. Foil packs: discard the first 3 trigger pulls coming out of themixer. This part of mortar is not allowed to use for fastenings !

Jumbo cartridge: discard a cone of mortar approx. 50 mm indiameter and 25 mm in height. This part of mortar is not allowed to

use for fastenings !

9. Inject the mortar into the bore hole until the bore hole is fullyfilled with mortar . Start filling from bore hole bottom andslowly withdraw the mixer/dispenser while filling the bore hole withmortar. Try to displace the water into the bore hole completelywith the injected mortar .

For deep bore holes use mixer elongation’s.

10. Insert the fastening element.

Regarding working/gel time “ twork / tgel” , initial curing time “ tcure,ini“ and full curing time “ tcure,full“ see “instruction for use”

If the water is flowing at the areas of fastenings mortar can beflushed out of the bore holes during curing time.

In this case protect the mortar around the fastening elementsby using a suitable protection discs (plastic, steel, washer, etc.)

see “Instruction for use”

page 2 and 3

For more information’s regarding setting details, cartridge handling, safety and waste handling revere to the

“Instruction for Use” of HIT-RE 500 which is by-packed to each foil pack or jumbo cartridge !







Hilti HIT-RE 500for


Anchor design:

Water saturated concrete, which is normal in underwater conditions, has less mechanical strengthcompared to dry concrete. The high-strength HIT-RE 500 injection mortar already uses the full load bearingcapacity of the base material. Therefor the lower mechanical performance of water saturated concrete hasto be taken into consideration when designing underwater fastenings.

The design of underwater fastenings for threaded rods HAS, HAS-R and HAS-HCR,internally threaded sleeves HIS-N and HIS-RN and rebars can easily be done using the design procedureand technical data published in the“Fastening Technology Manual (FTM)”, issue 2001 of Hilti Corp. Schaan, FL

As mentioned above, in underwater applications the base material is always water saturated.

So in each case the reduction factor f w,sat = 0,7 has to be taken into account.

For underwater constructions higher concrete qualities are normal. In Germany for example the min.concrete quality for such constructions is min. C35 (35N/mm2) is prescribed.Please check if Hilti’s request regarding minimum concrete quality of at least C20/25 for underwaterfastenings with HIT-RE 500 will be fulfilled.

Environmental aspects

Hilti HIT-RE 500 is listed by NSF for potable water applications. The listing is based on tests with curedmortar.During anchor installation part of the injected mortar is in contact with the surrounding water till full curing.During that time some of the mortar ingredients can be solved in the water.

Therefore underwater fastenings w ith HIT-RE 500 in potable water applications i s not allowed.In potable water applications the fastenings have to be made outside of the water.

In all other applications we recommend a min. application temperature of 10°C. This shortens the curingtime and therefore reduces the time for solving mortar ingredients. Also we recommend to collect the excess mortar out of the bore holes and take them out of the waterimmediately after setting.

We hope this technical information enables the HIT-RE 500 users to design and install high-qualityfastenings in underwater conditions.For additional support and application specific questions please contact your local Hilti technical service.

Hilti Development Anchors, KauferingH. Ginter R. Neuerburg

Enclosure: Pictures from underwater creep test.







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Picture 1 and 2: Sustained load test (creep test) of threaded rods HAS M12 and rebars ∅12mminstalled and tested under underwater conditions

underwater applications

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