Spraying UHPFRC for reinforcement and regeneration of pre-existing structures

Patent metadata

Field	Value
Publication number	US-11958773-B2
Application number	US-201917282458-A
Country	US
Kind code	B2
Filing date	Oct 2, 2019
Priority date	Oct 3, 2018
Publication date	Apr 16, 2024
Grant date	Apr 16, 2024

Abstract

A method for reinforcing a structure comprising the following steps:
preparation of UHPFRC comprising a cement precursor mix, of water, a fluidizing agent and metal fibers, transporting the UHPFRC by pumping to a suitable spray nozzle, spraying the mix onto a surface of the structure by the addition of a compressed air stream in the spray nozzle.

First claim

The invention claimed is:

1. A method for reinforcing a structure comprising:
preparing fiber-reinforced concrete comprising a cement precursor mix, water, a fluidizing agent and metal fibers, the fiber-reinforced concrete having a metal fiber content of at least 2% by volume of concrete;
transporting the fiber-reinforced concrete by pumping to a spray nozzle;
spraying the fiber-reinforced concrete onto a surface of the structure by the addition of a compressed air stream in the spray nozzle wherein the spray nozzle is mounted on an end of an intake pipe and comprises a triple-input intake for mixing of the fiber-reinforced concrete originating from the intake pipe with a single or dual compressed air stream, wherein pumping is carried out with a pump with twinned pistons;
a flow rate of the mixture from the pump is between 2 and 10 m 3 per hour; and
the spraying is performed wet by the addition of the compressed air stream with a compressed air flow rate at the spray nozzle of between 10,000 and 17,000 l/min and with an air pressure of between 5 and 11 bar.

2. The method as claimed in claim 1 , wherein the fiber-reinforced concrete has a metal fiber content of between 2 and 3.5% by volume of concrete.

3. The method as claimed in claim 1 , wherein the cement precursor mix comprises between 700 and 1000 kg of cement per m3 of mix.

4. The method as claimed in claim 1 , wherein the fiber-reinforced concrete has a water/cement weight ratio of less than 0.25.

5. The method as claimed in claim 1 , wherein the metal fibers have a greater mean dimension greater than 14 mm.

6. The method as claimed in claim 1 , wherein a working pressure of the pump is greater than 80 bar.

Assignees

• Soletanche Freyssinet

Inventors

• Huynh Tuong Alain
• Petit Bertrand
• Teply François
• Chaux Cédric-Olivier

Classifications

• C04B14/48 Primary

  Metal · CPC title

• C04B28/02

  containing hydraulic cements other than calcium sulfates · CPC title

• C04B40/0039

  Premixtures of ingredients · CPC title

• E04G23/0218 Primary

  Increasing or restoring the load-bearing capacity of building construction elements (E04G23/0203 and E04G23/0266 take precedence) · CPC title

• C04B2103/34

  Flow improvers · CPC title