HIGHWAY GUIDE – HIGHWAY GUIDE

METHODOLOGY OF CEMENT TREATED BASE /SUB BASE

1.0 Purpose

This provides details of Method Statement to be adopted for CTSB/CTB laying and compaction. For the functional requirement, the thickness of cement treated bases shall not be less than 100 mm.

2.0 Scope

This work shall consist of mixing, laying and compacting of aggregates mixed with cement in a mixing plant as a sub-base/base course on prepared subgrade/sub-base in accordance with the requirements of the Specifications and in conformity with the lines, grades and cross-sections shown on the drawings or as directed by the Engineer.

3.0 Equipment

Mixing Plant

Dumpers/Tippers

Water Tanker

Paver

Roller

4.0 Mix Design

The aggregate gradation for CTB shall be as given in table 400-4 of MORT&H specification. The CTB material shall have a compressive strength of 4.5 MPa in 7 days. The minimum cement content for the mix shall be 2%. Mix shall be got approved by the engineer prior to its use.

5.0 Trial

A minimum 100-meter length of the new carriageway trial patch shall be laid with using hydraulic mechanical pave finisher. Loose thickness of the layer, number of passes of vibratory roller to achieve 98 % modified proctor density, allowance for evaporation of moisture content, and line, level & cross fall shall be established during the trial. Before commencement of main work, trial patch should be got approved from the IE as per their satisfaction.

6. Responsibility

Section In charge will be responsible for quality control of the section for the construction CTSB/CTB. He will liaise with the Concessionaire Engineer In charge. Further he will be assisted by field engineers, surveyors, supervisors and lab technicians

7.0 Setting Out

The limits of CTB layer shall be marked by fixing pegs on both sides at regular intervals. The chainage boards & Bench Marks shall be set outside the limits of construction.

8.0 Procedure

Construction operation shall be as per Clause 403.3 of MoRTH or Chapter 5 of IRC SP 89. Before laying CTSB/CTB on already prepared sub base/sub grade , the shoulder shall be constructed first in order to provide confinement.

Material for the CTSB/CTB shall be prepared as per mix design in mixing plant. Moisture shall be maintained within tolerance range as determined by Mix Design. The mix shall be spread by a paver finisher in full width of a pavement as per approved drawing. In exceptional cases where it is not possible for the paver to be utilized, mechanical means like motor grader may be used with the prior approval of the Engineer. Maximum care shall be taken to spread the material uniformly. The compaction shall be carried out as per clause 403.3.5 with the help of vibratory roller of 8T to 10 T. Rolling shall be continued until the density achieved is at least 98 percent of maximum dry density.

The sub-base/base course shall be suitably cured for 7 days. Subsequent pavement course shall be laid soon after to prevent the surface from drying out and becoming friable. No traffic of any kind shall ply over the completed sub-base/base unless permitted by the Engineer.

9.0 Quality Control and Testing

Quality control tests shall be done as per Quality Control Tests and Acceptance Criteria as set in MORT&H 5^th revision. Of section 900.

METHOD STATEMENT OF CHECKING X – SECTION

Introduction : The purpose of this methodology is to measure physically the x section of the road on ground

Procedure : The following procedure to be adopted while taking physical measure :

The sample shall be taken on random basis
First lot of sample shall be taken by Independent Engineer
Start from outer side
First measure physically the width of drain
Then measure the width of the service road, separator, main carriage way and median
Continuously physically measure the length across the road width as stated above in each and every Km.
Compare each with the required TCS

Precaution :

Road should be barricaded by the safety cone
Two flagmen should be deployed with red flag to direct the traffic

PAVEMENT COMPOSTION METHODOLOGY

Introduction: The purpose of this methodology is intended for the finding out the crust thickness along the road.

Procedure: The procedure of finding out the crust/Pavement composition are under :

Decide the chainage from where the sample is to be taken on random basis
The first pit shall be selected by the Independent Engineer
Make a pit along the direction of the traffic in each stretch with regular interval of 5 km
Make a suitable size of pit on shoulder along the movement of the traffic with the help of JCB
After digging the pit measure the thickness of each component of the crust
Compare this thickness from the original Crust design.
Note down the thickness of each layer in prescribed format
This above procedure to be adopted along the the direction of the traffic through the project end.

Precaution :

Road should be barricaded by the safety cone

Two flagmen should be deployed with red flag to direct the traffic

Methods Statement Ultrasonic Pulse Velocity Testing

Introduction : This test is done to assess the quality of concrete ,this method consists of measuring the time of travel of an ultrasonic pulse passing through the concrete being tested. Comparatively higher velocity is obtained when concrete quality is good in terms of density, uniformity, homogeneity etc. There are mainly two transmission methods , direct and indirect . In direct transmission method of ultrasonic pulse velocity is passes on opposite faces directly(both faces) but in the indirect transmission method transmission arrangement is placed on same faces .This is least sensitive and shall be used when only one face of the concrete is accessible, or when the quality of the surface concrete relative to the overall quality is of interest. If the transducers and receiver has been placed in same side it will be called Surface probing . Indirect velocity is invariably lower than the direct velocity on the same concrete element. This difference may vary from 5 to 20 percent depending largely on the quality of the concrete under test. For good quality concrete, a difference of about 0.5 km/s may generally be encountered. For the procedure and for calculating the exact value of ultrasonic pulse velocity by surface probing. it is recommended by the code IS 516 (Part 5/Sec 1) : 2018 while using surface probing method the pulse velocity may be increased by 0.5

Reference code & Method : IS 516 (Part 5/Sec 1) : 2018 , Surface probing & Direct

Procedure : We will use surface probing method due to one face accessible (Indirect Velocity).

1.At the point of observation, the concrete surface shall be suitably prepared and any plaster or other coating shall be removed to expose the concrete surface. For this purpose, the use of carborundum stones or grinders may be adopted. However, care shall be taken to avoid any damage to concrete surface or concrete structure.

Before switching on the ‘V’ meter, the transducers should be connected to the sockets marked “TRAN” and ” REC”.
The ‘V’ meter may be operated with either:
a) the internal battery,
b) an external battery or
c) the A.C line.

3 . A reference bar is provided to check the instrument zero. The pulse time for the bar is engraved on it. Apply a smear of grease to the transducer faces before placing it on the opposite ends of the bar. Adjust the ‘SET REF’ control until the reference bar transit time is obtained on the instrument read-out.

Place the two transducers on opposite faces (direct transmission), or on adjacent faces (semi-direct transmission), or on the same face (indirect or surface transmission) . For maximum accuracy, it is recommended that the 0.1 microsecond range be selected for path length upto 400mm

5.Having determined the most suitable test points on the material to be tested, make careful measurement of the path length ‘L’. Apply grease to the surfaces of the transducers and press it hard onto the surface of the material. Do not move the transducers while a reading is being taken, as this can generate noise signals and errors in measurements. Continue holding the transducers onto the surface of the material until a consistent reading appears on the display, which is the time in microsecond for the ultrasonic pulse to travel the distance ‘L’. The mean value of the display readings should be taken when the units digit hunts between two value. Calculate the pulse velocity by using following formula

Pulse velocity=(Path length/Travel time)

Reporting the Result : While reporting the result surface probing system should be considered.

Precaution : Prevent the two transducer leads from coming into close contact with each other when the transit time measurements are being taken. If this is not done, the receiver lead might pick-up unwanted signals from the transmitter lead and this would result in an incorrect display of the transit time.

METHOD STATEMENT OF ROUGHNESS INDEX

Introduction: Roughness is the distortion in the road profile, which is of main concern to the road users. It is caused due to the inherent properties of materials and the construction techniques. The pavement surface roughness is expressed as Unevenness or Roughness Index (in mm/ km) measured through Fifth Wheel Bump Integrator or Car Axle Mounted Bump Integrator. Bump Integrator also known as Roughometer or Automatic Road Unevenness Recorder gives quantitative integrate evaluation of surface irregularities on an digital counter / LCD screen. It comprises of a single wheeled trailer, with a pneumatic tyre mounted on a chassis, on which an integrating device is fitted . The operating speed of the machine should be 32±0.5 km/hr. The machine is towed by a vehicle, usually a jeep without disturbing the accuracy of the unevenness-measuring wheel.

Reference Code : RC:SP:16-2019

Procedure : Following procedure should be adopted while performing the test on finished road:

1.For bump integrator reading, first decide the stretch to be tested

2.Then at starting point i.e. at 0 distance, the BI reading is adjusted to “0” cm.

3.The instrument is driven over the stretch with a speed of (32 +/- 2 km/h) on LHS and after crossing the end point marking; BI reading is taken and noted.

4.The result of bump integrator is generated in terms of count per km, which is the accumulation of the number of pulses in the total stretch.

5.Same test is repeated considering the speeds as mentioned above along in the stretches on RHS.

Recommended Standard Specification for Bituminous Concrete

<1800 mm per Km

METHOD STATEMENT OF REBUND HAMMER TEST

SCOPE: Compressive strength of concrete is very important criteria which can be easily computed by the Rebound Hammer .The rebound hammer is a nondestructive testing apparatus, whereby the rebound of the spring driven mass is measured after its impact with concrete surface. The output of the rebound hammer is referred to as rebound number and are correlated with surface hardness of concrete.

RERFERENCE IS CODE: IS 516 (Part 5/Sec 4) : 2020
PROCEDURE

a. For testing, smooth, clean and dry surface is to be selected. If loosely adhering scale is present, this should be rubbed off with a grinding wheel or stone. Rough surfaces resulting from incomplete compaction, loss of grout, spalled or tooled surfaces do not give reliable results and should be avoided.

b. The point of impact should be at least 25 mm away from any edge or shape discontinuity.

c. For taking a measurement, the rebound hammer should be held at right angles to the surface of the concrete member. The test can thus be conducted horizontally on vertical surfaces (preferably) or vertically upwards or downwards on horizontal surfaces. If the situation demands, the rebound hammer can be held at intermediate angles also, but in each case, the rebound number will be different for the same concrete.

d. Around each point of observation, six readings of rebound indices are taken and average of these readings after deleting highest and minimum reading means we have to take 8 readings

e. After the average reading find out the corresponding Compressive strength from the graph .

3. TEST RESULTS

Test result should record in in prescribed format

The report shall include the following:

a) Date/period of testing

b) Identification of the concrete structure/element

c) Identification of the rebound hammer;

d) Grade of Concrete

e) Test result and hammer orientation for each test area

METHOD STATEMENT FOR BRIDGE LOAD TEST

Purpose

Purpose of this test is too serve the behavior of the bridge by the application of design live load or load slightly exceeding design live load over a long period of 24 hours and elastic performance of bridge deck on removal of test load. It is used to assess the condition and safety of bridge. The load testing is used to check whether maximum deflection and percentage recovery are within permissible limits or not.

Relevant code

Bridge Load Test shall be conducted as per guideline provided in IRC: SP: 51-2015.

3. Scope & Provided by Sponsor

Scope of work includes conducting the Span Load Test.

a) Span Length – As per drawing

b) Test Span – As per drawing

c) Width of Carriage way – As per drawing

d)Test Load – As per drawing

Method of Loading – By filling suitable material in truck.

e) Location of Dial Gauge At L/4, L/2 and 3L/4 of the bottom side of girder.

(where L is the c/c distance between the bearing) as indicated in or as specified in Drawing

f) Dial Gauge to be installed for Test Span– 3 nos. Dial Gauge on one girder as mentioned in drawing.

g) Nos. of Dial Gauge to be installed for Bearings settlement – 2 nos. or as mentioned in drawing.

4. Test Set-up for Span Load Test

a. Deck shall be cleaned properly; white wash shall be applied at the critical section on Girders. Deck shall be marked for the loading area as per drawing.

b. Trucks loaded with suitable material like aggregate, sand, cement bags etc.

c. Deflection of girder shall be measured by Dial Gauge of 0.1 mm least count which detect the Dial Gauge which are fixed on bottom side of girder.

d. Wherever Dial Gauge cannot be fixed on bottom side of girder due to water flow under bridge. Then total station and Dial Gauge should be used on top of deck slab of bridge. Point of Dial Gauge should be marked on top of deck slab at distance of L/4, L/2 and 3L/4 or distance given in drawing according to alignment of girder.

5.PROCEDURE OF LOAD TESTING

1) The test will be carried out as per IRC SP 51 -2015 Instruments assembled at desired location such as, Dial Gauge, Strain Gauges & Digital Thermometer

2) Visual inspection of bridge is done. In Visual Inspection, Bearing and expansion joints will be checked. Both must be in their functional and working condition. The traffic will be closed for further testing and whitewash is applied to the superstructure for monitoring of cracks.

3) Dial Gauges will be placed on magnetic stands. Dial Gauges will be placed firm on scaffolding platforms with steel plates, so that magnetic stands are firmly located. Dial gauges were mounted just by touching the soffit of structure.

4) Glass plate of size 50x50x5 mm shall be fixed to structure at location of Dial Gauges for positioning.

5) Before loading the precautions should be taken.

a) All staging provided shall be stable and safe.

b) Staging for instruments and observers shall be independent.

c) Staging for instruments shall be rigid.

6) As per IRC SP 51, Loading Operation Stages from 50%, 75%, 90%, 100% of test load in 4 stages, which shall be completed in 4 hrs. At the starting of Bridge load test 50 % of load on bridge is taken, out of total 50% then 75% then 90% & 100% . We had to increment the load at the interval of every 1 hour during this the deflection will be recorded at each stage of loading.

7) After completing loading, we had to keep it retained for 24 hrs and observe.

8) After 24 hours, Structure shall be unloaded at same stage of loading i.e. 100% , 90% , 75% , 50% & 0%. But unloading shall be done in same way of loading , load shall be removed at 1 hour of interval from 100% to 90% to 75% to 50% to 0% as well as deflection is rewarded at each stage.

9) Measurements will be recorded at every hour of loading and unloading.

10) Data will be collected by visual observation before and after loading and there will be interpretation of results

OBSERVATION

The following observation shall be made before/during/after testing

i) Deflection at critical section

ii) Appearance of crack and their development, length and location

iii) Deformation of bearing

iv) Ambient temperature and relative temperature of the body in the structure

Temperature Measurement

Temperature of any component like pier, abutment wall of the bridge will be monitored at every one hour or as per drawing. For structure temperature, drill a hole and put digital thermometer in hole at any one point. Also environmental temperature should be recorded. The measurement will be taken by the digital thermometer. Reading of Dial Gauge point at every one hour or as per drawing should be note down for 24 hours. The reading of temperature will be used in temperature correction factor.

Method statement for slurry seal

Slurry is a combination or mixture of slow set bitumen emulsion , crusher dust with the addition of cement and water.
Application
It may be used to seal cracks,to provide a more even riding surface or a base for further treatment,before application, pothole and depression to be filled with proper bituminous material.

Material requirements

Aggregates:Suitable aggregate for slurry is graded crusher dust which is clean and free of any clay particles or organic materials.The crusher dust should comply with the specifications as stated in IS-383.A typical grading for suitable crusher dust is shown in the table below.Table 500-33 MORT&H

Sieve Size % Passing

9.5 100
4.75 90-100
2.36 65-90
1.18 45-70
0.600 30-50
0.300 18-30
0.150 10-21
0.075 5-15

Quantity of residual binder :Percentage by mass of aggregate should be 7.5 – 13.5

Water : Water shall be of such quality that the bitumen will not separate from the emulsion before the slurry seal is in place. The pH of the water must lie in the range 4 to 7.

Bitumen Emulsion : The emulsified bitumen shall be a Cationic rapid setting type as approved by the Engineer, conforming to the requirements as per IS: 8887.Slow setting bitumen emulsion is recommended .

Plant & Equipment Requirement :
Below is the list of plant required to mix and lay 5m3 or 700m² of slurry per day practically.

Item Number of items

Concrete mixer (0.3 m³) 1

Wheel barrows 3

Shovels 5

Pick 1

Containers (25 litres) 5

Container (1 litre) 1

Rubber squeegees 5

Hessian sheet (2m x 1.5m) 1

Watering can 1

Rope (10 mm diameter and 100m length) 1

Labour requirements

Below is the typical composition of a slurry team necessary to mix and lay 5m3 or 700m² per day.

Activity Number of workers

Loading of crusher dust 2

Concrete mixer operator 1

Pushing wheelbarrows 3

Loading emulsion and water 2

Spreading with squeegees 3

Sweeping 1

Traffic Control 2

Construction

Site Preparation

Slurry should be applied during the day, only in fair weather conditions. Repairs to potholes and depression should have been done prior to resealing with slurry.The surface on which the slurry is to be applied must be thoroughly swept and free of any debris.The surface must be dampened slightly before the slurry is applied.

Mixing by hand

The mix proportions will vary depending on the source and grading of the crusher dust .Before laying the slurry , a trial mix test should be carried out in a small container.Can be adust with water The typical mix proportions are as follows:
Material By (Agg)% % by mass(Overall)
Bitumen emulsion 13.5 10.5

Crusher dust 100 77.5

Cement 1.5 1

Water 14 11

Total (dry) 129 100

Remarks: % are shown with respect to crusher dust(100%) in 1st column and in 2nd column overall % has been given.

Work Sequences
The following mixing sequence is recommended to obtain a homogenous slurry mixture:
Step 1: Pre-wet the concrete mixer drum with approximately 5 litres of water
Step 2: Add the crusher dust into the concrete mixer
Step 3: Add the cement into the concrete mixer
Step 4: Mix the contents
Step 5: Pour water into the concrete mixer
Step 6: Mix again
Step 7: Pour in emulsion
Step 8: Mix contents
The emulsion must be at ambient temperature. To improve workability of the slurry, a controlled quantity of additional water should be added until the slurry has a creamy consistency . The water quantity will vary depending on the type of aggregate source its moisture content and prevailing air temperature.

Laying by hand
Slurry can be applied in a layer thickness of 4 mm-5mm.. A rope may be used to ensure straight edges and to control the cover thickness.
For instance to obtain a layer depth of 5 mm slurry, a 10mm diameter rope should be used.

After mixing, the slurry is transported in wheelbarrows to the point of application. The slurry is thenremixed on the road surface and spread with squeegees to obtain a uniform consistency and thickness.
The newly applied slurry layer is finished by dragging a wet hessian sheet over it to achieve a uniformly textured surface.If required rolling can be done with PTR depend upon condition

Traffic control

Slurry takes approximately four hours to set and dry properly under favourable weather conditions and no traffic should be allowed onto the freshly laid slurry before it has dried sufficiently. A suitable means of assessing this is to check whether the slurry can withstand the turning force of a shoe heel under a person’s weight without scuffing.

Quality control
Before construction commences the mix components should be mixed in their predetermined proportions in a small container to determine their compatibility. The resultant mix should be shaped into a patty and allowed to dry in the sun for a visual inspection.

The following tests should be carried out on site during the execution of the works:

Daily: Bulking test on the crusher dust to determine whether the mix proportions require adjustment.
When the water source is changed, dilute the emulsion 50:50 with the water in a glass container to check whether the fluids are compatible.

The key variables that must be checked regularly are the grading of the crusher dust being supplied and the binder content of the final slurry mixture. To this end samples of the crusher dust and wet slurry mixture should be tested in a soils laboratory.

SOUNDNESS TEST OF CEMENT BY LE – CHATELIER METHOD

A cement is said to be unsound if the hydration of a hardened paste of it is eventually accompanied by excessive expansion, causing cracking and reduction in strength.
Accelerated hydration procedures are used routinely in cement production to check that it does not possess this property. The simple apparatus devised by Le Chatelier is used to indicate the expansion of a paste.Here we will discuss about the practical of soundness test of cement

Standard Used

IS 4031 PART 3

Objective

To determine the soundness of cement.

Equipment

The apparatus for conducting Le-Chatter test shall conform to IS: 5514 – 1969.
Balance of capacity 500 grams and sensitivity 0.01gms.
Water bath capable of raising the temperature from 27+ 2⁰C to boiling point in 27 + 3 minutes.

Procedure

Take representative sample of cement and mix with 0.78 times the water required to give a paste of standard consistency as per IS: 4031 (Part 4) 1988.
Place a lightly oiled mould on a lightly oiled glass and fill it with this cement paste.
Prepare the paste in a manner and under the conditions all as per IS: 4031 (Part 4) 1988.
Keep the edges of the mould gently together during this operation.
Cover the mould with another piece of lightly oiled glass sheet and place a small weight.
Immediately submerge the whole assembly in water bath maintained at a temperature of27 + 2⁰C and keep there for 24 hours.
After 24 hours remove the mould from the water bath and measure the distance separating the indicator points (E₁).
Again submerge the whole assembly in water bath at a temperature of 27 + 2⁰C and bring the water to boiling in 27 + 3 minutes and keep it for 3 hours.
Remove the mould from the water bath, allow it to cool and measure the distance between the indicator points (E₂).
The distance between the two measurements indicates the expansion of the cement.
Make at least two determinations for each test.

Calculation

Calculate the Soundness of cement from the equation given below

Soundness = E₂ – E₁

E₁= Initial distance between the indicator points.

E₂= Final distance between the indicator points.

Report

Report the individual and the mean results to the nearest 0.5mm.

Precaution

Take care to maintain the temperature of the moulding room, dry material and water within 27 + 2⁰C and the humidity of the laboratory within 65 + 5%.

Method Statement for Pipe Culvert

1.0 Purpose
This work shall consist of furnishing and installing reinforced cement concrete pipes, of the type, diameter and length as per design and details and at locations shown on the drawings .

2.0 Scope

The scope of work includes the following
Excavation
Head Wall construction
Bedding for Pipe
Laying of pipes
Jointing
Back Filling

3.0 Equipment

Backhoe loader/excavator
Formwork
Transit Mixer
Vibrator
Batching plant
Dewatering Pump, if required
Dumpers

4.0 Materials
All materials used in the construction of pipe culverts shall conform to the requirements of Section 1000 of MoRTH.
Each consignment of cement concrete pipes shall be inspected, tested before incorporation in the work and should conform to IS 458.

5.0 Responsibility
Section Incharge will be responsible for quality control of the section for the construction of Kerb. Further field engineers, surveyors, supervisors and lab technicians will assist him.

6.0 Procedure

6.1 Excavation
The foundation bed for pipe culverts & Head wall shall be excavated true to the lines and grades shown on the drawings

6.2 Head Wall

PCC of specified grade and thickness shall be laid to the specified dimension and level for leveling course below head walls as per approved drawing
The layout of the Head wall shall be made on the PCC as per approved drawing
The formwork shall be fixed to true line, levels, plumb, etc., rigid, adequately braced both horizontally and vertically. Form joints shall be as much as minimized shall be tight and shall not permit any leakage of slurry from concrete.
• Concreting of head wall shall be carried out in two stages according to site conditions.
• first stage shall be done up to bottom of hume pipe.
• second stage concreting shall be carried out. After placing and aligning all the pipes.

6.3 Bedding for Pipe

The bedding shall be sand / granular material passing 5.6mm sieve. Specified thickness of granular material bedding shall be provided below the pipes as per the approved drawing. The bed shall be compacted/rammed with adequate water.
In case of high embankments where the height of fill is more than three times the external diameter of the pipe, the embankment should be built first to an elevation above the top of the pipe equal to the external diameter of the pipe, and to width on each side of the pipe not less than five times the diameter of pipe, after then trench for pipe bedding should be excavated.

6.4 Laying of Pipes

• The arrangement for lowering the pipes in the bed shall be done carefully so as not to cause damage or undue strain to the pipes, preferably it shall be done by means of tripod, manual labour or by cranes for loading, unloading & setting the pipes.
• The gap between two rows of pipes shall be at least 450 mm or half the diameter of the pipe, whichever is maximum for new culvert and existing gap shall be maintained for widening of the existing culverts.
• The laying of NP4 pipes shall start from the outlet end & shall be completed at the inlet end to specified lines & grades as specified in the approved drawing.

6.5 Jointing

• The pipes shall be joined by flush joint. The ends of the pipes especially shaped to form self centering joint with a jointing space 13mm wide. The jointing space shall be filled with cement mortar 1:2 sufficiently dry to remain in position. The jointing shall be made with care so that the interior surface is smooth & consistent with the interior surface of the pipe. The joints shall be kept damp for at least four days till the joints are sufficiently hardened.
• The existing head walls shall be dismantled to the required level and dimension as per the approved drawing. New pipe shall be jointed with the existing pipe as shown in the approved drawing.

6.6 Pipe Encasing

Pipe encasing if any, shall be carried out as per the approved drawings .

6.7 Back Filling

Trenches shall be backfilled after the completion of jointing and encasing. The backfill soil shall be free from boulders, large roots, organic soil and any deleterious material and should be approved from the Engineer.Care should be taken while backfilling upto 300 mm above the top of the pipe , the soil should be thoroughly rammed, tamped or vibrated in layers not exceeding 150 mm, special care should be taken while consolidating the materials under the haunches of the pipe. Approved light mechanical means or tamping equipment can be used this purpose.
Filling of the trench should be carried out simultaneously on both sides of the pipe in such a manner that unequal pressures do not occur.
In case of high embankment, after filling the trench upto the top of the pipe , a loose fill of a depth equal to external diameter of the pipe shall be placed over the pipe then after further layers should be added and compacted.

7.0 Quality Control Testing and Acceptance

Quality control tests shall be done as per Sl. No 10 & 14 of Quality Control Tests and Acceptance Criteria .

8.0 Safety & Environment

While working Safety & Environment Procedure shall be followed as per approved EHS Manual.