Pipeline Coating Process

8/13/2019 Pipeline Coating Process

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may not be achievable: in such case a technical query should be raised and agreed to.

Reinforcement

All reinforcement shall meet the minimum specified % cross sectional area (CSA)

requirements .

There are commonly two methods of reinforcement; rigid preformed cages

(usually manufactured on site using Zublin machines) and wire mesh fabric.On occasions both methods are used simultaneously. (This usually occurs

where high thickness concrete coatings are required).

Zublin Machine

Typical Zublin made Cage

Where rigid preformed cage reinforcement is used, the cages are fitted tothe pipe prior to the concrete application process. Wire mesh fabric

however, is wound into the concrete during the concrete application

process. .

Cage reinforcement shall normally be required to meet the requirements of

BS 4482, BS4449 or ASTM A615/A615M using wire with typically

diameters of 5 mm for longitudinal and 7-8 mm for circumferential.

Welded wire fabric reinforcement shall normally be required to meet the

requirements of ASTM A82 for zinc coated drawn wires, Typically one layer

of wire is required for concrete thicknesses up to 55 mm above 55 mmconcrete thickness two layers minimum are required.

Potable water

Coating http://pipecoating.blogspot.com/

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Responsibilities:

The Incoming Supervisor shall ensure that the incoming holiday detection, reinforcement

installation, fitting of end rings and end plugs are performed correctly. He shall quarantine

pipes that are in need of repair and supervise the repair operation. He is also responsible for

ensuring that all tasks are conducted in the safest possible manner.

The QC inspector/Auditor shall be responsible for the release or quarantining of the incoming

pipe. He shall maintain checks in accordance with function described in an agreed inspection

Test Plan (ITP)

The tally man shall be responsible for maintain pipe traceability and recording the disposition

of rejected and repair pipes.

3.0 Mixing of Concrete

Prior to concrete coating, the batch plant, cement hopper and water feed systems are

calibrated to allow accurate percentages of constituent materials to be delivered to the mixer.

Typical constituents of the concrete mix are cement, high-density iron ore, sand and water.

The concrete mix design is dependent on the Specific Gravity of materials being used and is

proportioned accordingly.

Typical Batch Plant Calibration Tolerances

Cement 2%

Aggregates 3 %

Water 2%

Whole 3 %

Sand/aggregates are typically transported from their respective stockpiles to the Mixing Plant

hoppers using rubber tired front end loaders. From the feed hoppers the sand and aggregate

are metered into the mixer at the mix design quantities. Cement is typically auger fed from

the cement silo into a weigh hopper which weighs off the required amount to meet the mix

design requirement.

Note:where aggregates are stored in outside open areas the working face of the stockpiles

should be regularly turned over to maintain even moisture mix in the material. It is

inadvisable to take the material from the very bottom of stockpiles where moisture is likely to

be exceptionally high,

Typical Batch Plant feed System


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After weighing, the cement is added to the aggregate in the mixer. After a period of dry

mixing, water is metered by volume into the mixer and the batch mixed for the prescribed

mixing time. On completion of the mixing the concrete is conveyed to the short feed hopper.

From the hopper the fresh mix is gravity fed onto a short belt which in turn progresses the

mix to the concrete application head.

Note:Regular samples of the fresh concrete mix shall be taken from the feed belt to enable

moisture content and fresh analyses to be carried out. Also for mix control purposes fresh

mix test cube specimens are prepared.

Cube Making


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Cube Samples

Responsibilities:

The Batch Plant Supervisor shall be responsible for batch p lant calibration and operation. He

is to ensure that the parameters set through batch plant calibration are maintained

throughout production. conveying aggregates to and from the correct holding hoppers

ensuring that the correct amount of water is added to the concrete mix to provide consistent

moisture content of the mix. He shall also be responsible in ensuring that the task is

conducted in the safest possible manner.

The QC laboratory Technician shall be responsible for ensuring concrete mix calibrations are

carried out correctly, taking samples of the concrete mix for analyzing and preparing samplesfor testing. He shall also be responsible for consistently reporting test results to the Batch

Plant Supervisor, and for logging all test results.

4.0 COATING PROCESS:

From the impingement incoming rack or indexer, pipes are placed on the concrete coating

line rotation buggy s using an overhead crane using a spreader bar and suitably protected

hooks. On the rotating buggy s the pipes are transported past the impingement coating head

where premixed concrete is applied at high velocity to the pipe using impingement rollers.

The concrete plant operator selects the pipe rotation and forward travel speeds at a setting

that allows for the concrete to be applied to the correct concrete coating thickness.

Pipes with anodes fitted are coated as per a plain pipe with the exception that a shadow plate

and plastic wrap covering the anode is utilized to prevent excessive concrete covering the

anode. After processing the plastic wrap shall be removed and the outer surfaces of the


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Anodes shall be cleaned and be free of concrete coating materials.

Diameter or thickness of the concrete coating is controlled by measurement using a girth or

tree tape and is performed at the coating head and again verified at the weigh station.

Note Where wire mesh fabric reinforcement is used, the wire fabric is fed from a spool

tensioning arrangement then travels though guides and onto the rotating pipe as the pipe is

being impinged.

Welded Wire Fabric Feed

5.0 CLEANING AND WEIGHING STATION

Upon completion of the concrete coating, the pipe cutback areas are cleaned, the end plugs

are removed and any debris in the pipe interior is also removed. The OD of the concrete is

again measured: taking six equidistant measurements along the pipe.

Taking Girth Measurements


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Note: The concrete ends shall be finished square to the pipe axis and the crown of the

concrete shall be slightly rounded.

When all redundant material has been removed from the coated pipe, the pipe is weighed

using a calibrated weigh scale or load cell.

Pipes that are out tolerances for thickness and or weight may be flash coated or scraped to

enable correct tolerances to be achieved. This rectification process shall be carried out whilst

the concrete is in a green state and only if agreed to by the client.

At the cleaning station continuity (anode to pipe) and isolation (rebar to anode & pipe) and

reinforcement position checks shall be performed on pipes in accordance with the agreed

inspection frequency included in the Project inspection Test Plan (ITP)

Reinforcement placement check

Note : In the case where welded wire is used for reinforcement, the excess wire on the finish

end of the pipe is trimmed back to just below the concrete surface to ensure no protrudingwire is on the concrete surface.

Excess Wire Fabric

When accepted the details of the pipe weight and girth measurements are entered into a pre

programmed computer that determines the negative buoyancy (NB) of the pipe.

A typical formula for NB calculation

Weighing devices used to determine the weight of the concrete-coated joints shall be

certified in writing to accuracy of 0.5%. The calibration of weighing equipment shall be


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checked by test weighing method previously approved by contractor unless other procedures

have been agreed and confirmed in writing. Calibration of the weighing equipment shall be

checked daily.

The unsaturated (as applied) submerged weight per metre (N/m) for each pipe shall be

calculated from the pipe weight in air immediately after coating.

The submerged weight, W (N/linear metre), shall be calculated using the

following formula:

where:

Mc = Mass of fresh concrete coated pipe including reinforcement kg

Dc = Outer diameter concrete coated pipe m. Average of 6 girth measurements

Ds = Outer diameter of steel pipe plus twice the anti-corrosion coating thickness, m

P1 = Density of field joint filing materials (assume 1025 )

I = Cutback of concrete coating from bevelled end, m

L = Mill length of steel pipe, m

Pw = Density of seawater (assume 1025 )

SW = Submerged weight

For anode and crack/buckle arrestor pipes, the specified maximum submerged weight may

be exceeded. Variations in buoyancy shall be ignored and the submerged weight value shall

be adjusted by using an increased weight in air. The Principal shall specify the allowable

weight variations in the Scope of Work.

The results shall be recorded and tabulated against pipe number and presented to the

Principal at the completion of each day s production. The submerged weight of each coated

pipe shall be within the acceptance tolerances stated by the Client in the Scope of Work.

Responsibilities:

The concrete plant supervisor is responsible for ensuring that all equipment and personnel

are adequately organized to carry out concrete batching, placement of reinforcement,

coating, repairing and checking all coating parameters. He is also responsible in ensuring

that the task is conducted in the safest possible manner.

The concrete plant operator is responsible for maintaining the correct mix design, travel and

rotation speeds, placement of reinforcement, end rings and anode protection.

The coating Tally man is responsible for recording the traceability of the coated pipes, the

correct recording of pipe weights, pipe lengths, coating diameter, cutback lengths and

submerged weight (NB) calculation. He will also keep an ongoing log of running (NB)

averages.

The QA inspector/Auditor is responsible for the correct calibration of the weigh scales (NB

station), periodic checking of any repairs to anti corrosion coating, the concrete coatingparameters, including wash out checks of the reinforcement, overlaps for reinforcement and

periodic isolation/continuity checks.

6.0 CONCRETE CURING

Submerged


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From the cleaning area acceptable coated pipes are lifted by overhead crane onto trucks

having suitable cushioning and supports that protect the green concrete. The pipes are

transported to the curing area where the freshly concrete coated pipes shall be laid out in

single layers approximately 250 mm apart on suitable sand berms using either an overhead

gantry or mobile crane.

Pipes that are to be cured using the Fog Cure method shall be covered as soon as practical

with a tarpaulin and fog water spray shall be introduced via water pipes fitted with fine

misting nozzles under the covers to maintain a high humidity beneath the covers.

The pipes shall remain in the cure bay until the concrete has achieved a minimum stacking

strength of 14 Mpa (as determined by concrete cube strength testing). On completion of the

curing process and prior to stacking the cutback end rings shall be removed and any

concrete contamination shall be removed from the coating steel cutback and internal bore.

Pipes selected for concrete coupon testing shall be clearly marked and placed on hold in an

area suitable for coupon extraction work to be performed. Coupon holes shall be repaired in

accordance with the approved Concrete Repair Procedure.

Note:Test cube specimens taken from the fresh mix at the batch plant shall be placed in the

curing bay and cured in a manner identical to the pipe.

7.0 REPAIRS

Repairs to the coatings shall be carried out in accordance with an approved Repair

Procedure. Coated pipes that cannot be repaired shall be rejected, stripped and re coated.

Unacceptable pipe shall be marked up with Red/White hazard tape and recorded on the NCR

system.

After the completion of acceptable repairs the pipe will then be placed in its allocated storage

area. The stacking height for concrete coated pipes shall be in accordance with the approved

handling procedure.

Repairs on freshly applied concrete shall be carried out at the coating plant whenever

appropriate or at the curing bay.

Typical repair procedure

Upon visual examination, concrete coatings that are damaged, are defective or do not meet

with requirements shall be repaired. The circumstances of the damage or defects will dictate

the appropriate method of repair.

Repairs Criteria

If the area is less than 0.8m in any 3 m length of pipe may be repaired by hand patching

providing that such repairs are carried out within 4 hours of concrete application.

If the area is more than 0.8m but less than 25% of total coating repairs shall be made usinggunite. The concrete remaining shall be undercut to provide a key lock.

Cracks caused by excessive deflection in handling or storage, with the following criteria shall

be repaired by chiseling the crack not less than 25mm and repair shall be made using the

same basic material as the coating:-

Cracks in excess of 5mm width and extend over 180 circumferential around the coated pipe.

Cracks which are between 250mm 1000mm in length longitudinally along the coated with

the addition that the ends of each crack shall be drilled with a hole of 10mm nominal

diameter to prevent crack propagation. The bottom of these holes shall be 7 -10mm from the

anti-corrosion coating.

Cracks extending halfway through the concrete or penetrated to the cage

Longitudinal surface cracks of any width and less than 250mm in length shall not be

considered a defect but holes of 10mm nominal diameter shall be drilled at the crack tips to

prevent crack propagation. The bottom of these holes shall be 7 -10mm from the

anti-corrosion coating.


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Surface damage shall not be considered a defect if :-

The total surface area of damage per pipe is less than 0.1 m, and

Max depth does not exceed 20% of coating thicknesses, and

The remaining concrete is sound.

Damage at the ends of the concrete coating need not be repaired provided that the damaged

area is less than one third of the circumference for a length less than 200 mm.

Hand Repairs

Damaged areas may be repaired by hand patching in its green concrete state. Patching

shall be carried out by removing the defective area down to underneath the reinforcement

and undercutting the sides to form a key. The cavity formed shall be filled with a mix similar

to that used in the coating process with the addition of just sufficient water to allow hand

application. Polythene wrap shall be used to seal the repair before curing. Maximum

allowable time between concrete coating and repair of green pipe will be 4 hours.

Core Holes

Prior to filling cores holes, each site will be inspected for damage to the anti-corrosion

coating. Damage to this coating will be brought to the attention of QC personnel and the

Customer. Core holes shall be repaired using concrete with the same proportion of

constituents as the original coating.

Core holes may also be repaired using concrete repair material Mapegrout Fast-Set

(manufactured by Mapei) or Certite or similar product. A slight increase in water content

may be considered acceptable to aid cure for some of the materials. The material shall be

trowelled in such that the surface level is continuous with the level of the existing coating

around the repair.

Gunite Repair Criteria

Repair on cured concrete coating and large repair areas shall be rectified using the gunite

method of repair. The size of the gunite repairs shall be demonstrated and witnessed for

suitability as an addendum to the Pre qualification trials for concrete coating. The concrete

mix design used for gunite repairs will be of the same constituent make up as that of theparent mix material apart from the use of extra water to assist with the application. Curing of

the repairs will be carried out by wrap sealing of polyethylene membrane.

Gunite Repairs

GREEN CONCRETE

Damaged or defective areas shall be prepared by undercutting and exposing the

reinforcement throughout the damaged area and removing any loose concrete material. The

area shall then be filled by Gunite application until the entire repair area is reinstated to the

level of the parent material. The completed repair shall be dressed in a manner that allows a

smooth transition to the parent material. Within 30 minutes of the repair completion the green

concrete coated pipe shall be placed in the fog cure.

CURED CONCRETE

Shall be performed as that for green repairs with the addition of a water wetting application to

the cured concrete coating interfaces prior to Guniting. The repair area shall have a curing

membrane tightly affixed and shall stay in place for a minimum of 48 hours to allow sufficient

cure.

Testing

Repair materials used for concrete repairs shall be tested for compressive strength as

determined by 28 day cube strength results. The minimum strength to be achieved shall bethat of the strength specified for the parent coating. The frequency of testing shall be at

start-up, middle and end of project.

Responsibility


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The repair foreman shall be responsible for coating repairs and shall ensure the correct

equipment and repair method is used for coating repair. He shall also be responsible in

ensuring that the task is conducted in the safest possible manner.

QC, Inspector/auditor shall be responsible for checking the preparation and the completed

repair.

All repairs are to be recorded and inspected for compliance to the repair method statements.

8.0 PIPE MARKING AND IDENTIFICATIONThe identity of each pipe shall be established and entered into the pipe tracking system such

that traceability is maintained. Accepted pipes will be released for transportation to the

stockpiles or other processes.

Typical Marking Requirements

Pipe no

Length

WT

Heat no.

Date of coating

Responsibilities

Load out Tally man, shall ensure that the correct pipe markings are applied in accordance

with the agreed marking system. He shall also be responsible in ensuring that the task is

conducted in the safest possible manner.

QC, Inspector/Auditor shall be responsible for inspecting that the correct colour banding and

markings are applied.

9.0 SACRIFICIAL ANODE INSTALLATION

Anode are typically fitted to the corrosion coated pipe prior to caging and concrete coating,

however in some circumstances anodes can be retro fi tted i.e. after concrete coating.

Process Description

The Coated line pipe shall be positioned on the support racks, over the

anode lifting saddle. The pipe will be positioned until the longitudinal seam

weld (if any) is located around either the 12 or 6 o'clock position or

approximately 150mm of the weld seam. Once positioned the lifting saddle

will raise the lower half shell of anode to the stationary pipe and hold it in

position. The second half shell of anode shall be offered to the pipe and

positioned over the first half shell, by means of crane jib. The two halvesshall be carefully aligned and drawn tightly together using webbing

tensioners, chain come-along or similar.

The centering of the anode along the pipe shall be in a manner that allows

for casing segments to be fed onto the pipes.

Fit Up


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Electrode Handling

Fillet Welding

Welding will be by metal arc process

Fillet welding shall be carried out continuously around three edges of the

overlapping straps of the anode halves. An insulating material shall be

placed under the weld area to guard against heat damage to the anti

corrosion coating.

Thermit Weld

Fillet Weld

Welding consumables will be SMAW electrodes for carbon steel.

Electrodes shall be baked for 2 hours at 325oC and held at 150

oC in a

suitable holding oven prior to use. Alternatively, follow manufactures

instructions. The Welder shall keep electrodes in an approved quiver during

use and return unused electrodes to the holding oven when not working.


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Pipe Preparation:

Areas of anti corrosion (TLPE) coating are be removed within each gap

between half shells, each area of removal shall be as small as practical to

accommodate the Thermit Graphite Mould

The removal of coating shall be achieved by using a heated knife and / or a

bolster type chisel cutting around the heated area that is to be stripped,following the removal of the coating the steel substrate shall be power

ground to achieve a bright, clean roughened surface or St 3.

Connecting of Bonding Leads (Electrical Connection):

Each anode is normally manufactured complete with bonding leads; the

bonding leads may be cut to size using a cable cutter or hacksaw to

remove. The cable should be looped (pig tailed) so as not to be taut after

welding.

The end 25mm of PVC/PE sheathing is stripped back to expose clean

copper cable. The cable may be cleaned with a wire brush if required.

Cad welding process as follows:

Clean the conductors and position them in the well dry mould;

Place the metal retaining disc in the bottom of the crucible graphite mould;

Pour the welding metal powder into the graphite crucible, spread starting

powder onto the graphite mould edge;

Open the mould lid and ignite the welding powder using a flint gun by firing

the spark onto the starting powder;

The exothermic welding process takes place inside the graphite mould; and

finally the exothermic connection is finished.

Clean the mould using scraper and brush and proceed to the next

connection cable(s) ready for connection.

After welding, each completed weld shall be tested for electrical continuity

and mechanical bonding strength (1 blow with a 1 Kg Hammer)

Electrical Continuity using Ohm meter


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Anti corrosion Coating:

Subsequent to the satisfactory completion of anode installation, the

anti-corrosion coating shall be reinstated as follows:

The exposed areas of steel substrate around the Cad weld and anode

straps shall be wire brushed to a clean finish. All bare steel shall then be

coated using SOLVENTLESS2 PACK EPOXY or other approved repair

material.

Anode Completion:

After final inspection, the Anode completion procedure will be carried out,

consisting of the infilling of the gaps between anode halves with either a

gunite concrete or hot poured marine mastic method.

The reinforcement used during concrete coating shall be trimmed back from

the edges of anode allowing a 25- 50mm gap. Electrical continuity test

shall be carried out to ensure that the reinforcement is electrically isolated

from the anode/pipe.

The gaps between the anode and the parent concrete weight coating

shall in filled with either a concrete mix similar to that of the parent coating

material (by hand or gunite method) Or by other approved in fill methods

(for example moulded hot bitumen) On completion a continuity check

between Anode and the steel pipe shall be performed prior to moving the

pipe to storage.

Inspection control:

Pre-qualification

The anode installation procedure and inspection shall be pre-qualified prior

to the start of production.

The pre-qualification will be limited to anode closure (strap) and Cad welds.

Weld / Welder Qualification

Typically each welder shall perform one fillet weld on a test coupon

sometimes supplied by client. The test coupon shall be macro sectioned

and tested for hardness.

All required tests shall be carried out and reported by credited 3

rd

PartyInspection Laboratory.

Thermit Weld Qualification


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The test welds and coupons shall be sectioned and tested for copper penetration by a third

party inspection house

Hardness shall not exceed 248 Hv10 when taken at 2mm intervals extending to 10mm either

side of the extreme edges of the weld.

No cracks or penetration of alloying elements along grain boundaries by more than 0.5mm or

any non-metallic inclusions will be detected at 200X magnification.

10.0 OFFLINE TESTING

Specific Density

Sieve Analysis

Moisture Content

Deleterious Substances

Fresh Analysis

Water Absorption

Compressive Strength Cubes

Compressive Strength Cores

Impact Test

Shear Test

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SPECIFIC GRAVITY - BS 812: part 2 1985

Note:This practice may be modified by the requirements of the customer s specification, see

relevant Project Inspection Test Plan (ITP)

Scope

Determination of the Specific Gravity (SG) of Aggregate/Iron Ore

Equipment

Pycnometer

Electronic balanceGas ring or oven

Procedure

Obtain a sample weighing approximately 2000 grams.Thoroughly wash the sample to

Typically each production welding operative will be qualified by

demonstrating their capability to perform a series of Thermit welds on a

coupon sample. Each weld shall be mechanically tested by a single blow

from a 1kg hammer, aimed at 90 degrees to the sample surface - no lifting

or fracturing shall result. Electrical continuity test shall be carried out

between pipe and anode

The macro sectioned and hardness and penetration tests reports will be

identified by coupon unique numbers. Test results should meet the

following:


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remove all material finer than No. 200 Sieve (75micron).Dry the retained sample over the gas

ring (or oven) and then allow it to cool to room (ambient) temperature.

Place 500 g of dry aggregate (Weight, A) into the Pycnometer and fill it with water. Whilst

filling rotate the Pycnometer to eliminate all traces of trapped air within the sample material

and allow settling. After settling, top up the Pycnometer with water again to remove any froth

from the surface so that the water level in the hole at the to of the cone is flat and level. Dry

the exterior of the Pycnometer and weigh (Weight, C).

Empty all the contents of the Pycnometer into a tray, making sure that the aggregate is

completely emptied. Refill the Pycnometer to the original level with water (only), dry the

exterior and weigh (Weight, B).

The difference in water temperature between the first and second weighing shall not exceed

2C.

Carry out the test twice.

Evaluation

Calculate the Specific Gravity of the aggregate as follows:

Specific Gravity (SG) = Weight A / ((Weight A + Weight B) Weight C))

Report

Record Specific Gravity

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SIEVE ANALYSIS (GRADATION) OF AGGREGATES - ASTM C 33


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Scope

To establish a Sieve Analysis (Gradation) of aggregates using interlocking, circular sieves of

standard aperture sizes

.

Equipment

Nest of certified sieves

Sieve shaker

Calibrated weigh scale

Oven or gas ring

Sampling box

Oven trays

Plastic bucket

Sampling scoop

Procedure

A representative sample of material to be analyzed shall be taken in a proper sapling

method. The sample shall be at least 1500 grams.

The sample shall be weighed and the weight recorded. After weighing the sample shall be

oven or gas ring dried making sure that none of the sample is spilt from the heating tray.

After drying the sample shall be passed through a set of known mesh size sieves, making

sure that all the sample is removed from the heating tray. The sieves shall be interlocked in

order of aperture size, starting with the larges mesh size at the top.

The interlocking sieves (including bottom pan) shall be agitated sufficiently (normally with the

aid of mechanical vibrator/shaker) for a period of time (usually 4 minutes minimum), to

ensure that the material has completely passed through the respective grade sizes.

The aggregate which is retained in each of the sieves and the bottom pan are then

individually accurately weighed and the weights recorded.

Calculations

After the mass of aggregate retained on each sieve and in the receiver has been determined,

calculations are then carried out. Note that mass retained and mass passing on each sieve

are recorded and percentage passing is eventually calculated from the obtained results.

Visual representation of the particle size distribution is carried out be means of gradation

graph showing the sieve aperture size against the percentage passing that particular sieve

size.

Due to the relative values of the aperture size, it is convenient to plot them to a logarithmic

scale.On completion of plotting, the points of the plot are joined together with straight lines resulting

in a graph that is termed the gradation curve.

Evaluation of results

The obtained grading curve should be within the envelope limits drawn by the applicator and

approved by the client and/or limits extracted from the ASTM C33 Standard.

Report

The type of aggregate

Results and percentages calculate

Sieve Analysis


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MOISTURE CONTENT OF AGGREGATES



Scope

Determination of the mass of water in an aggregate, expressed as a percentage of the mass

of the oven-dry, sample material.

Equipment The moisture content can be determined by any one of two methods.

An oven or gas ring

A calibrated weigh scale

Oven pan

Speedy moisture content tester (alternative method)

Procedure & Calculation (oven/gas ring dried method)

The sample is weighed, and then, after being oven- dried, it is re-weighed. Weigh the

masses before and after drying W1 and W2, respectively, then:Moisture content, % = (W1 W2) / W2 x 100

Use of Speedymoisture content tester (use only in case of accelerated test)

This is a proprietary device whose action is based on the very rapid absorption of water by

calcium carbide. Standardized quantities of aggregate and calcium carbide are mixed by a

standard procedure in a hand-held, sealed pressure vessel. Acetylene gas is formed by the

action of the moisture on the calcium carbide, and the pressure of the gas is related to the

quantity of moisture. The vessel is fitted with a pressure gauge calibrated to give a direct

reading of the moisture content.

Note :This test is unsuitable for larger sizes of coarse aggregate.

Report

Moisture Content in %

Moisture Content


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DELETERIOUS SUBSTANCE IN AGGREGATES - ASTM C40-92



Scope

To determine the organic impurities, including silt and clay in the aggregates

Apparatus

Glass bottle, 500ml

Sodium hydroxide solution, 3% NaOH

Reference color standards

Procedure (extract from ASTM C40-92)

Preparation of solution :

Dissolve reagent grade potassium dichromate (K2Cr207) in concentrated sulfuric acid (SG

1.84) at the rate of 0.250 g/ml of acid. The solution must be freshly made for the color

comparison by gently heating, if necessary, to effect solution

.

Fill a glass bottle to the 130ml level with sample of aggregate to be tested.and add the 3%

NaOH solution into the bottle until the volume of the aggregate and liquid after shaking is

about 200ml.

Cork the bottle, shake it vigorously and allow it to stand for 24 hours.afterward fill a fresh

glass bottle to the 75ml level with reference standard color solution prepared not more than 2

hours earlier per the preparation procedure described in Sub-clause B.3.1

Compare the color of the supernatant liquid of the test sample with that of the reference color

solution.

Record the color comparison result to that of the reference standard, e.g. lighter, darker or

same color.

Evaluation

If the color of the supernatant liquid is darker than that of the referenced standard, the

aggregate tested is considered to contain possible traces of injurious organic compounds. As

such perform further tests.

Report

Record


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Deleterious Substances

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FRESH ANALYSIS

Note:This practice may be modified by the requirements of the customer s specification,

see relevant Project Inspection Test Plan (ITP)

Scope

To verify W/C ratio, cement and aggregate content of the concrete mix. This procedure

applies to fresh concrete coating drawn from the batching mixer or feed conveyor to the

application head.

Equipment

Set of test sieves

Mechanical sieve shaker

Calibrated Electronic balance to an accuracy of 1.0g

Gas ring (to accelerate drying)

BucketGunny sacks

Procedure

Prior to carrying out a mix analysis, it is necessary to carry out a gradation on a

representative sample of each aggregate used in the concrete. It is also necessary to know

the nominal mix design in percentage terms.

Obtain a representative sample of at least 2kg of freshly mixed concrete from the feed belt,

place in a suitable bucket , cover the bucket with a damp gunny sack and immediately

transfer the sample to the laboratory. This test shall be carried out without any delays.

Weigh a 500g sample into a tray and determine the moisture content of the sample.

Weigh a further 1,000g into a 150 micron sieve. Wash this sample carefully under a gentle

flow of clean water until the water draining from the sieve is clean and clear. Be very careful

to ensure that no material spills over the side of the sieve.

When washing is complete, transfer the cleaned sample onto a tray, using a further quantity

of clean water to wash all traces of material out of the sieve and into the tray. Carefully drain

off excess water, making sure that no material is lost in the process.

Place the tray over a burner and dry it thoroughly. Ensure that the rate of drying is gentle

enough to prevent material being ejected from the tray as the water vaporises, or alternately

cover the tray with an identical tray to trap any ejected material.

Once the sample is completely dry, remove from the heat and allow it to cool before

transferring to the sieve stack.

When the sample has been placed into the sieve stack close the sieve stack securely and

operate the shaker for five minutes. Remove the stack from the shaker. Carefully separate

the nested sieves and weigh and record the amount of material retained on each sieve,

ignoring the contents (if any) in the sieve pan.

Input the weights into the pre formatted calculation spreadsheet, or alternatively write by

hand on a blank fresh mix analysis form. For manual calculation, the procedure is as follows:

Record the weight on each sieve in turn

Determine the cumulative weight retained on each sieve by adding the weights of all

previous sieves in the stackDetermine the dry weight of the 1,000g sample used for each sieve

Calculate the cumulative weight retained as a percentage of the sample dry weight

For each sieve, calculate the percentage of the dry weight passing that sieve by subtracting

the value from the previous step from 100%


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The preformatted spreadsheet automatically calculates the mix ratios. To do this manually,

the following procedure is used:

Determine the weight of fines ( < 150 micron) particles of each aggregate in the mix sample

by multiplying the percentage of that aggregate passing the 150 micron sieve (from the

aggregate gradation) by the percentage of that aggregate in the mix by the dry weight of the

fresh mix sample.

Example: If 15% of the sand passes the 150 micron sieve in the sand gradation, and the mix

design incorporates 20% sand, and the fresh mix sample weighs 1,000g with a moisture

content of 6%, then the weight of sand fines in the sample is:-

15% x 20% x (1,000 x 94%), or 0.15 x 0.2 x 1000 x 0.94 = 28.2g

Repeat this step for each aggregate, and total the weights determined in this way. This

gives the total weight of fines in the fresh mix sample.

From the fresh mix gradation, calculate the total weight passing the 150 micron sieve by

subtracting the cumulative weight retained on that sieve from the dry weight of the sample.

This is the apparent weight of cement in the sample.

Note, this weight will include fine particles of aggregate. Subtract from it the total fines

weight calculated previously. The result is the corrected weight of cement.

Subtract the corrected weight of cement from the dry weight of the mix sample. The result

is the corrected weight of aggregate.

Determine the weight of water in the sample by multiplying the sample wet weight by the

moisture content.

The water to cement ratio is given by dividing the weight of water by the corrected weight

of cement.

The aggregate to cement ratio is given by dividing the corrected weight of aggregate by the

corrected weight of cement.

Report

Record

Fresh Analysis

Fresh Analysis

-----------------------------------------------------------------------------------------------------------------------

CONCRETE DENSITY

Note:This practice may be modified by the requirements of the customer s specification, seerelevant Project Inspection Test Plan (ITP)

Scope

To determine concrete density on removed samples (coupons or cores) removed from a


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concrete coating.

Equipment

Balance sensitive to 1.0g

Container suitable for transporting coupons to lab/cure bay

Core drilling equipment (core sampling)

Hand tools to assist in removal of samples

Wire cutters (coupon sampling)

Test specimen

Draw specimen (coupon) at production line taken immediately after coating or from a cure

pipe (core) dependant on the agreed method of sampling.

Procedure (coupon method)

Brush the sample with a fine bristle brush to remove all loose particles from the sample

surface.

Weigh sample and record as Weight A.

Transfer the sample to pipe curing bay with the pipe and allow the sample to cure for the

same period of time as of the coated pipe (a minimum of four (4) days). Sample may also be

oven dried to the constant weight.

Procedure (coupon and core)

After cure immerse sample in seawater filled tank at room temperature for not less than 24

hours. Draw sample from tank, let it surface dry or remove excess surface moisture, weigh

and record as Weight B.

Suspend the sample from a wire and weigh it in water and record as Weight C (this is to

check bulk density of concrete).

With the weights determined in accordance with the above procedures, calculate the

following:

a) Water absorption after Immersion, % = (B A) / A x 100

b) Density (Air- dry), Kg/m3 = A / (A C)

c) Density (Saturated), Kg/m3 = B / (B C)

Report

Record

Sample ID

Concrete coating date

Sample type

Calculation and results

Density

Density Test


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------------------------------------------------------------------------------------------------------------------------

COMPRESSIVE STRENGTH OF CUBES



Scope

Preparation and testing samples of concrete for compressive strength properties using the

cube mold method of sampling.

Equipment

100mm Cube Molds

Trowel

Bucket or Container

Vibrating hammer complete with square face (50mm x 50mm) tamping foot

Calibrated Compression Testing Machine.

Procedure

Draw concrete samples of the production working mix from the conveyor during transfer of

concrete from the mixer to the application head. Ensure that only freshly mixed concrete is

used for the sampling.

Place sample material in a bucket and over the bucket with a moist gunnysack to prevent

premature dehydration of the sample.

Prepare the required amount of cubes required for each sampling period plus two extra

cubes to used as spares. Make the test cubes as soon as practicable after sampling to avoid

dehydration.

Fill each test cube mold with concrete in three layers of 50mm. Compact each layer until

refusal using a vibrating hammer equipped with a square faced tamping foot attachment.

On completion of compacting the topmost layer of the sample the surface shall be prepared

level with the top edges of the mold using a square edged trowel. Each sample shall be

marked with it s ID and sample number. Also for day night operations the ID should include

the letters D/S or N/S

Curing of sample

Immediately after the sample preparation, cover the molds with a moist gunny sack and

place the cubes in the fog cure. Check closely that an uninterrupted moist condition exist

throughout the curing period.

After overnight curing, the mold screws are loosened, the mold dismantled and cube sample

is carefully removed and placed in a water tank. The samples shall remain saturated until

required for crushing.

Note :ensure that before placing the samples in the water tank that a correct, legible ID

exists on each sample


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Compression Testing

The testing machine shall be capable of applying load manually or automatically at the

specified rate uniformly without shock. It should be annually (or anytime when anomalies in

the results are

observed) be calibrated and certified by 3rd

Party Certifying Agency for compliance.

Prior to testing each sample shall be weighed (in saturated state), in kilograms.The

dimensions of the samples shall be measurement in mm.

Determine the density of each test cube either by obtained weight over cube measure or by

water displacement method.

After weights, measurements and densities have been determined the test cube shall be

placed between the testing machine platens ensuring that all bearing surfaces of the testing

machine platens and the sample are wiped free of any debris.

Carefully center the cube on the lower platen, ascertaining that load will be applied to the two

opposite cast faces of the cube in a correct and even manner.

Without shock, apply and increase the load continuously at a nominal rate within the range of

0.2 - 0.4N/mm per second until no greater load can be sustained.

Record the maximum load applied to the cube.

Calculation and expression of the results

Calculate the cross-sectional area of the cube face f rom the checked nominal or measured

dimensions.

Calculate the compressive strength of each cube by dividing the maximum load by the cross-

sectional area of cube.

Express the results to the nearest 0.5N/mm2 or any otherwise agreed units.

Report

RecordConcrete Compressive Strength (Cube Sample)

NOTE : The drawing and Test on drilled CORES is in accordance with BS1881Part 120.

Cube: Core Compressive Strength Correlation (if required) is carried out by this standard

Compressive Strength Cubes

--------------------------------------------------------------------------------------------------------------------------

COMPRESSIVE STRENGTH OF CORES - BS1881



Scope

Preparation and testing samples of concrete coating for compressive strength properties

using the extracted core method of sampling.

Equipment

Core drill, support stand and correctly sized core bits

Calibrated Compression Testing Machine.

Facing saw

External calipers

Acetate film


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Capping compound

Bucket, Container or plastic bags

Water & Power source

Procedure

Pipes selected during production for core sampling shall be clearly marked CORE TEST

and the pipe number and date coated shall be entered into the laboratory LOG

After a curing period (minimum 48 hrs) the core test pipe shall be located in the designated

area for core drilling. The core drilling equipment shall be checked for good working condition

and properly connected to the power source. The core drill bit shall be of a size that will allow

35 45 mm diameter cores to be removed. Core diameters shall remain constant throughout

the project. Only suitably qualified/trained operators shall perform core drilling.

The core drilling rig shall be firmly located on top of the pipe ( 90) and the core drilled in a

downward direction. Whilst drilling, water shall be used to lubricate the drilling bit and the

core rig shall be fitted with a positive stop system to ensure the core bit does not exceed the

limitation of penetration (being 7 mm from the PE coating). Core samples shall NOT betaken from the end 300 mm of the concrete coating.

On completion of drilling, the core drill, including core shall be carefully removed from the

concrete coating. The core sample shall then be carefully removed from the drill bit. When

removed, all cores from the test pipe shall have a band of electrical tape fastened around

them on which the pipe number shall be marked using a ball point pen. The cores shall be

placed in unique plastic bag for each test pipe. DO NOT MIX CORES FROM OTHER TEST

PIPES. The bag containing the cores shall also be clearly marked with the test pipe number.

When received at the laboratory the cores shall be removed from their respective bags and

checked for condition and quantity. If more cores are required, advise the core man as soon

as possible. All cores are to be trimmed and left to dry for 24 hours. When dry, the cores shall

be capped (apart from cores that will be used for density and water absorption tests). These

cores will be capped later. When capped, each core top cap shall be identified with the date

coated and with the letters D (day) or N (night) and placed into the storage tank with the

identification facing upward. The same procedure will apply to density and water absorption

samples after tests are complete. Cores will be stored in a water tank maintained at 23

2C.

Crushing

Specimens shall be removed from the curing tank and shall be in saturated condition when

tested, ideally removed from the tank approximately 30 minutes prior to crushing.

Select appropriate testing machine platens to suit anticipated compressive force. Clean

platen surfaces and ensure absence of extraneous matter. The core-seating rig (if required),

fabricated in accordance with BS 1881, is placed in the centre of the location circle and thecores inserted.

Apply the load, without shock, at a nominal loading of 0.2 N/mm2/sec. - 0.4 N/mm2/sec. at a

constant rate for cores. Observe the fast advance and ensure seat correctly on the

apparatus. Operate the controls as failure is approached to maintain load rate(s) above as far

as practicable. When failure occurs the maximum load applied shall be recorded.


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Report

Record

The specimen ID

Pipe number

Compressive strength to the nearest 0.5 MPa

Core Samples

Core crushing

---------------------------------------------------------------------------------------------------------------------------

WATER ABSORPTION



Scope

Determination of water absorption on sample removed from concrete coating (coupon or core)

Determination of water absorption using a fully coated concrete pipe (full-scale method)

Equipment

TestSample

Calibrated Balance

Container suitable for immersing sample

Fresh concrete sample (at least 500 grams)

Full Scale

Calibrated weighbridge or load cell

Suitable water tank

Crane


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Procedure (Sample testing)

Brush the removed sample (coupon or core) with a fine bristle brush to remove all loose

particles

from the sample surface.Weigh dry sample and record as Weight A.

Transfer the sample (coupon) to pipe curing bay with the pipe and allow curing for the

same period of time as the coated pipe.

Immerse sample in seawater tank at room temperature for not less than 24 hours. Remove

the sample from the tank, let it surface dry or remove excess surface moisture before

weighing and record as Weight B.

Suspend the sample from a wire and weigh it in water and record as Weight C (this is to check

bulk density of concrete).

Calculate the water absorption of the sample as follows:

a) Absorption after Immersion, % = (B A) / A x 100

Calculate the bulk density as follows:

b) Bulk Density (Air- dry), Kg/m3 = A / (A C) IF REQUIREDc) Bulk Density (Saturated), Kg/m3= B / (B C) .. IF REQUIRED

Procedure (Full scale method)

Weigh a fully concrete coated pipe that has been cured record as weight A.

Place the pipe in a water tank filled with seawater at room temperature, if fresh water is used

a

calculation between sea and fresh water shall be used in the calculation process.

Allow the concrete to fully saturate, normally 24 hrs

After 24 hrs remove the pipe from the water tank and allow all free water to drain off. Weigh

the

pipe and record as weight B

Calculate the water absorption of the concrete coated pipe as follows;

Absorption after Immersion, % = (B A) / A x 100

Report

Record

Sample(coupon)

Full scale water immersion

Water Absorption sample

Water Absorption test


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-------------------------------------------------------------------------------------------------------------------------

IMPACT TESTING OF CONCRETE



Scope

This procedure applies to concrete coated pipe subjected to repeated Impact simulating the

pipe movement during transportation and handling at lay barge during installation. It is

carried out to determine concrete integrity when subjected to high impact energy.

Equipment

Impact testing rig

Test Pipe with concrete coating

Timer

Tape measure

Striker edge: 10mm radius

Hammer Weight 2,680 Kg and/or 1,840 Kg

Camera

Procedure

The test shall be carried out 90 to pipe axis at one location.

The test shall be supported with a minimum of 2M concrete sections on either side of the

section under test. Impact blows (5 times) shall be directed on the same location. Hammer

should have a vertical drop of 660mm giving a velocity of impact of 3.60 m/second (7 Knots).

After each impact a photograph of the impact area shall be taken together with a sketch of

spalled areas including dimensions of cracks (length and width).

Acceptance criteria:- Typically


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The anti- corrosion coating shall not be visible after impact (5 blows).

Spalling has not occurred further than 300mm from the impact location.

Report

Record

Impact Testing of Concrete

Impact Test Rig Drawing

---------------------------------------------------------------------------------------------------------------------------

SHEAR TEST OF CONCRETE



Scope


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To evaluate the inter facial shear strength between the anti-corrosion and concrete coating

applied to a pipe.

Equipment (typical)

200MT Hydraulic Jack complete with pressure gauge

Supporting fixtures (design to suit testing set-up)

Measuring gauge for displacement of upper platen

Calibrated dial gauge

Procedure

A pre prepared coated section of pipe shall be selected having concrete pipe sections of

minimum of 500mm test length. The preferred maturity of the coating is a minimum 7-days

after coating.

Oxy cut from a cured concrete coated pipe approximately 900mm concrete coated test pipe.

Cut only one test piece from each individual coated pipe. Alternatively, pipe can be coated

partly at a section length of 0.50 to 0.90 meter located at one end of pipe (proximity to

cutback). This is depending on what fixture is available from the time of carrying out test.

After having cut the test piece, prepare the cross-sectional surface of the concrete at one end

so that it is near perpendicular to the axis along the piece length.

Carefully center the test piece on the lower platen of the Hydraulic Jack (Compression

machine) unit with the concrete section supported by the appropriate supporting fixtures.

Then slowly lower the top platen to just touching the steel pipe end. Without shock, apply and

increase the load continuously at a nominal rate within the range of 0.2N/mm2 per second

until no greater load can be sustained.

Record the maximum load applied and calculate the surface area (SA) of the anti- corrosion

coating surface as follows:

Surface area, mm2 = 3.1416 x d x L

Where,

d = Pipe OD + anti-corrosion coating thickness

L = Length of concrete coating

Minimum required load (Kg-f) = 0.17N/mm2 x SA / 9.81

Report

Record

Shear Testing results

Shear Bond Test


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