Concrete Repair Method Statement (Structural Lifting, Shotcrete, Epoxy) https://methodstatementhq.com/concrete-repair-method-statement.

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Concrete repair refers to m odification of structure which is dam age in its appearance
or serviceability. It also involves to restore the structure partly or wholly, the pre-
existing characteristics of serviceability, load-bearing capacity and if necessary, to
im prove its durability.

Concrete structures deteriorate due to a num ber of processes leading to cracking and
spalling of the concrete.

Replacem ent can take tim e and m ay require lengthy operation if we talk about the
structural elem ents having a lower intrinsic longevity than the service life of the
whole structure.

There are different co n cre te re p air te ch n iqu e s useful to restore the structural
integrity and shape of a concrete elem ent which generally include rem oval of
dam aged concrete and replacem ent with new concrete.

The planning, design, im plem entation and m onitoring of a concrete repair and/ or
strengthening activity m ay include following objectives:

Ascertaining the present state of the structure

Establishing the repair and/ or strengthening requirem ents
Preparation of a repair program
Determ ining the required target condition of the structure after repair and
strengthening
Re-checks and inspection controls.

Structural Lifting and Supporting

Shotcreting
Repair of Structural Mem bers Dam aged by Corrosion
Concrete Patch Repair
Epoxy Injections for Structural Cracks
Repair of Expansion J oints
Repair of concrete water tanks and waterproofing

Stru ctu ral Liftin g an d s u p p o rtin g

This m ethod of repairing of concrete involves m echanical lifting of settled grade slabs
or in som e cases, even a part or whole of the m ain structure itself and supporting
them in the lifted position by m eans of piles or pressure grouting.

In this case we need suitable equipm ent for lifting i.e. hydraulic jacks with pum ps,
lifting fram es/ accessories and Dywidag bars with anchoring system .

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The advantage of this concrete repair approach is that it does not require excavation.
You can upgrade the grade slab’s capacities with m inim um disruption, disruption to
floor finishes is also m inim al. Fast operation when we com pare with all other
available m ethods and finally cost effective in saving the structure.

Me th o d State m e n t fo r Stru ctu ral Liftin g an d s u pp o rtin g

Drill holes and construct the piles to suite the design load.
Support the lifting fram es on the constructed piles using tem porary stools.
Anchor the Dywidag bars to the slab to be lifted and connected the Dywidag
bars to the lifting fram e.
Lift the fram e against the constructed piles by m eans of hydraulic jacks in
between them .
The lifting of the fram e will enable the slab also to be lifted, adjust the slab to
the required level.
Rem ove the jacks and lifting fram e one by one, by connecting the lifted slab to
the pile perm anently.

Sh o tcre te Co n cre te re s u rfacin g & Re p airin g

Sh o tcre tin g is another process of repairing the concrete. This m ethod is useful if
there is reinforcem ent corrosion or other deterioration.

Also beneficial to strengthen any structural elem ents by a m ixture of cem ent,
aggregate and water, with or without adm ixtures.

The m ix is projected at high velocity from a nozzle in to place as a continuous stream

without interruption.

Com paction to produce a dense hom ogeneous m ass is achieved by the m ixture’s own
velocity.

Shotcreting m ethod is useful for:

co n cre te re p air of large areas of concrete deteriorated due to reinforcem ent

corrosion or other reasons,
strengthening of existing concrete colum ns, beam s and slabs by increasing the
co n cre te s e ctio n al are a by the application of shotcreting
and by increasing the steel and construction of structures with com plex shapes,
where the preparation of shuttering is difficult and com plex.

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Typ e s o f Sh o tcre te Re p airin g

D ry Sh o tcre te Pro ce s s

In this m ethod, the cem ent and aggregate are batched and m ixed without added
water, and fed into the delivery gun.

The m achine feeds a continuous and even am ount of m ixed m aterial under high air
pressure into a high velocity stream of dry air in the flexible delivery hose.

W e t Sh o tcre te Pro ce s s

Water is introduced as a spray at a special nozzle at the discharge end.

In wet process conventional concrete or grout pum ping equipm ent is generally used.
A suitable m ix is pum ped to the discharge nozzle along a flexible delivery hose.

An additional air supply is introduced at the discharge nozzle, to speed up the flow
and im part sufficient velocity so that the m aterial is com pacted on im pact.

Sh o tcre te Co n cre te Re p a ir Me th o d State m e n t

Rem ove all distressed concrete from the affected structural area and a
m inim um of 20 m m behind the steel reinforcem ent.
Sand blast substrate to rem ove loose concrete and to rem ove the corrosion in
the steel.
Reinforcem ent which has lost m ore than 15% of its cross sectional area shall be
supplem ented with new reinforcem ent.
Protect the application area to avoid over spray.
Apply the shotcrete, perpendicular to the substrate, ensuring full encapsulation
of reinforcem ent and good bond with the substrate. You can leave the
shotcreted surface as-shot or can form to a sem -sm ooth surface, as per the
requirem ent.
Most concrete repair works use aggregate of less than 5m m m axim um size and
type I cem ent. The aggregate cem ent ratio for a dry process is generally 3.5 : 4.0
: 1 by weight. The water : cem ent ratio in dry process is low (typically 0 .38 to
0 .41).
The concrete placem ent characteristics are good density, low perm eability, high
strength (typically 30 to 40 N/ m m 2) and good bond to suitable substrate.

Co n cre te Re p air Me th o d State m e n t u s in g Ep o xy

The Project Manager has the overall responsibility for ensuring that all the concrete
defects are com plete in accordance with the specifications, m anufacturer’s
recom m endations, Method Statem ent and Safety procedures.

Construction Manager is responsible for execution of this work and to arrange all the
m aterials, equipm ent and other requirem ents as necessary.

Site Engineer to ensure that the responsible personnel are fam iliar with the m ethod
statem ent and safety requirem ents of the activity. Also to m ake sure that risk
assessm ent is available on the project site before start of work. Site Engineer to
ensure that the work force is fam iliar with the activity, hazards and m itigation effect

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of the situation.

QC Engineer to inspect the work and ensure the com pliance to the requirem ents /
specifications.

Project Safety Officer is responsible for ensuring that the activities are carried out as
per the project specific safety regulation s. Evaluation of all possible risks i.e. risk
assessm ent and to ensure that all precautionary m easures are in place prior to start
the activity. He shall ensure the im plem entation of all necessary requirem ents
regarding the health safety environm ent concerns.

Site Forem an to ensure that the workers understand their duties and perform quality
work in accordance with m ethod statem ent and m anufacturer’s recom m endations.

Equ ip m e n t fo r Co n cre te Re p airin g

Below is the list of equipm ent / tools m andatory for epoxy repairing / painting works:

Paint Brushes/ Roller

Air Com pressor

Grinder
Industrial Vacuum Machine
Hand tools (Trowel, Spatula or Putty knife/ scraper, ham m er etc.)

Ste p w is e Me th o d fo r Ep o xy Co n cre te Re p airin g

MasterBrace ADH 220 0 is a non slum ping epoxy bedding com pound and
adhesive.
It is a two pack, fine aggregate filled, fast curing m aterial, ideal for a variety of
bedding, gap filling and concrete repair applications.
MasterBrace ADH 220 0 is a stiff but easily workable com pound that can be
applied by trowel, spatula or knife. It cures to give high m echanical properties
typical of epoxy com pounds. Its im pact resistance and m echanical strength is
greater than that of concrete.
Apply the MasterBrace (concressive 220 0 ) strictly in accordance with
m anufacturer’s recom m endations and relevant applicable procedure.
Store and place the m aterial in a cool and dry place. Protect all the m aterials

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from direct sunlight and keep in safe place.

Barricade the area under progress with this activity and provide necessary
warning sign boards as per project safety plan.

Cracks Re p airin g Me th o d :

Cracks occurs in substrate shall rout out, by chasing with chisel or grinder. After the
surface preparation is com plete, rem ove all the dust from the surface using an
industrial vacuum m achine. It is best practice to do vacuum cleaning before the start
of each of the coat.

Mixin g:

MasterBrace ADH 220 0 (form erly known as CONCRESSIVE 220 0 ) is available in two
com ponents. Mix com ponent A and B together until you obtain a uniform streak free
color.

Ap p licatio n :

By using a spatula, apply the m ixed m aterial into the routed out cracks, forcing the
m aterial into the concrete surface. Sm ooth off the surface and rem ove surplus
m aterial after application. To fill the blow holes etc. tight trowel the m aterial into the
prepared surface.

Ad van tage s

High strength.
Non-slum p.
Strong adhesion.
Im pact resistant
Chem ical resistant.
Non shrink.
Epoxy based.
Trowels to a sm ooth finish.
Easy to use.
Supplied in pre-weighed units.
No bonding agent or prim er required.

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