Contractor Support for Machine Applied Concrete Repairs

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Concrete Repair According to European Standard EN 1504

The Added Value of Concrete Repairs by Machine Application

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In the new European Standard EN 1504 Part 9, Principle 3 defines the application of repair mortars by machine as well as by hand.

There are two different types of machine application:

n The Dry spray process

n The Wet spray process

The selection of the best application method and the most appropriate repair material is dependent on the different requirements of each project and the site conditions and its situation.

This brochure is intended to illustrate the advantages of machine application and also gives an overview of how to select the right method and equipment for each type of application together with the corresponding Sika materials.

Criteria for Selection of the most Appropriate Application Method

The evaluation process to decide on the best application method is dependent on different application and performance requirements witch can obviously vary greatly on different types of project and from site to site. The following table gives the most important criteria for the contractor to consider and then select the most suitable and efficient application method.

n Faster application: Means reduced downtime and lower support costs

n Reduction of labour costs: Efficient repair works by reducing the number of operatives required

n Easier application: Especially for overhead applica-tion, thick layer reprofiling and application under dynamic load

n Reduction of accidents at work: Less manual work reduce the chance of accidents

n Improved quality: Higher compaction of the material improves its technical quality

Wet Spray Process:

n Mechanical Mixer

n Spray pump machine (worm screw or pressure plate)

n Air compressor

n Hoses of different lengths

n Nozzles

Dry Spray Process:

n Rotor spray pump machine

n Air compressor

n Hoses of different lengths

n Nozzles

Material properties:

n Excellent pumpability: Mortar should be soft but with good thixo-tropic behaviour (wet spray)

n Easy to mix in both small and large quantities

n Long pot life to prevent blockages in the hoses in case of equipment problems or delays

n Excellent finishing

n Good adhesion to the substrates

n Good cohesion of applied material (especially in overhead applica-tions)

Added Value Equipment Sika MaterialMethod 3.1 according to EN 1504-9: Application of mortar by hand.

Method 3.3 according to EN 1504-9: Spraying mortar or concrete (dry or wet spray application).

Criteria Application Method

Machine Hand Dry Wet

Economical aspects:n Cost efficiency for large repair volumes (>500 kg/day) *** *** 0n Cost efficiency for small repair volumes (

Comparison of the Wet and the Dry Spray Proc esses

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The Wet Spray ProcessAdvantagesn Better yieldn Minimal rebound n Minimal site protection requiredn Suitable for application in confined spacesn Easy trowel finishing n Easier QC-proceduresn Reduced dust generationn These mortars can also be applied

by handn Constant mortar consistency

How it worksThe mortar is put into the pump hopper as a dry powder and fed by compressed air in a thin stream to the point of application. At the back of the nozzle the powder is mixed with water, including accelerator if required and propelled to the substrate at a pressure of about 2 bar.

(Process equipment: Aliva AL-246.5 resp. AL-252.1 etc.)

How it worksThe mortar is first mixed and then fed in a plastic consistence and as a dense stream by pump to the point of application. Air is added at the nozzle, which then dissipates the mortar and propels it onto the substrate.Accelerators can not be added at the nozzle. (Typical equipment: Putzmeister S5 EVTM, Inomat M8, etc.)

Rebound 25%Compaction 1 :1.35

1000 l 750 l 555 l

Air streamconveyance(thin stream)

Compressedair

Dry mix

Water + accelerator if required60 90 cm

The Dry Spray ProcessAdvantagesn Highest outputn Equipment blockages are raren Low equipment cleaning costsn Long equipment lifen No premixing requiredn No grout priming requiredn Higher early strengthsn Long feed distances are possiblen Frequent stop/start sequences are easyn Thicker layers in a single operation

Concrete in Hopper Concrete on WallConcrete in Hopper Concrete on Wall

Hydraulicconveyance(dense stream)

Air streamconveyance(thin stream)

Compressedair

Wetmix

Air for stream converter

Streamconverter

Rebound 10%Compaction 1 : 1.03

1000 l 900 l 875 l

Air forconcretepump

20 50 cm

1

2

3

4

5

1

2

1

2

15 b

15 c1815 a

17

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Sika Repair Materials designed for Machine Application and the Spray Equipment

Corrosion Protection/Bonding Agent

SikaTop Armatec-110 EpoCem Cement based, epoxy modified, three component material.

Sika MonoTop-910 Cementitious, one component material.

Concrete Repair: Wet Spray Process

Sika MonoTop-412 NCementitious, one component repair mortar, containing silica fume.

Sika MonoTop-352 NFG Cementitious, polymer modified, one component repair mortar with light weight aggregate and corrosion inhibitor.

Concrete Repair: Dry Spray Process

Sikacrete Gunite-103 One component, cementitious repair mortar, containing silica fume.

SikaCem Gunite-133 One component, cementitious, polymer modified repair mortar, containing silica fume.

Pore Sealer/Finishing Coat

Sikagard-720 EpoCem Three component, epoxy modified cementitious protective levelling and sealing mortar.

Sika MonoTop-723 N Cementitious, polymer modified, one component, pore sealer / finishing coat, containing silica fume.

Effective chloride penetration barrier, also provides corrosion protection for steel reinforcement. Excellent bonding coat with extended open times for repair mortars.

Bonding agent for repair mortars; it also provides corrosion protec-tion for steel reinforcement.

Repair mortar with outstanding workability and excellent shrinkage behaviour. Contains fibres and silica fume. Developed specially for the wet spray process, but can also be applied by hand.

Light weight repair mortar with excellent application and shrinkage behaviour. Additional performance benefits are also obtained from the polymer and corrosion inhibitor (Sika FerroGard Technology).

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High build, large volume repair mortar with good workability pro-viding dense, well bonded repairs which can easily be float finished.

Very high build, large volume repair mortar providing dense repairs with excellent bond that can be trowel finished to the highest stan-dards.Suitable for use with Cathodic Protection systems, where the slightly higher resistivity will spread current more evenly in over-lays of the anodic mesh (ref. Mott MacDonald Report 37423-4/98).

Thin layer levelling mortar which is suitable for aggressive envi-ronments and which needs no additional curing.

Thin layer levelling mortar for horizontal and vertical surfaces. Fills surface irregularities and small voids.

n Hopper content: 6 ltrn Weight (empty): 1.5 kgn Air requirement: 220 l/minn Required air pressure: 2 to 3 barn Adjustable aperture

n Process: Wet spray applicationn Conveying volume: 0.4 2.4 m3/hn Conveying distance:

horizontal up to 70 mn Pump pressure: max. 25 barn Dimensions: LWH (mm):

22906801150n Motor: 400 V/50 Hzn Capacity of the vessel: 100 ltrn Weight: 400 kg (inkl. Mixer)

n Process: Dry spray applicationn Conveying volume:

10 ltr rotor 5.2 m3/h 16 ltr rotor 8.4 m3/h

n Conveying distance: horizontal up to 300 m, vertical up to 100 m

n Dimensions: LWH (mm): 17008001450n Motor: 400 V/50 Hz /4.4 kW

Compressed air motor: 9 m3/h n Weight: 780 kg

n Process: Wet spray applicationn Conveying volume: 0.4 2.4 m3/hn Conveying distance:

horizontal up to 70 mn Pump pressure: max. 25 barn Dimensions: L WH (mm):

22906801150n Motor: 400 V/50 Hzn Capacity of the vessel: 100 ltrn Weight: 400 kg (inkl. Mixer)

Hopper Gun

Mortar Pump for Wet Spray Application, e.g. Putzmeister S5 EVTM with Mixer TM 100

Universally Applicable Dry Spraying Machine, e.g. Aliva AL-252

Mortar Pump for Wet Spray Application, e.g. Putzmeister S5 EVTM with Mixer TM 100

The Sika Repair Materials for Machine Application The Recommended Equipment for Machine Application

Product Main Advantages Equipment Technical Description Spray Equipment

1 Nozzle for mortar 1 to 8 mm2 Nozzle for finishing coat 0.5 to 1.0 mm

Dry spraying hand pistol 32 + 38 type standard

15 b Nozzle (with O-ring) 32/2715 c Nozzle (with O-ring) 38/3215 a Nozzle (with O-ring) 32/18

18 Blast nozzle, sand17 Flexible nozzle

1 Gun with adjustable aperture2 Hopper3 Quick disconnect4 Hose 13 mm, 10 m long5 45 Adaptor for application over head

(Independent air compressor is needed)

1 Nozzle for mortar 1 to 8 mm2 Nozzle for finishing coat 0.5 to 1.0 mm

mm 50 40 30 20 10

kg 100 80 60 40 20

02

46

810

02

46

810

02

46

810

Overspray

50%

40%30%

25%15%

Rebo

und

Wavin

essSurfaceroughness

F/2 F/2F

Load sp