HIGHWAY GUIDE – HIGHWAY GUIDE

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.

Method Statement For Backfilling Behind Abutment & Around Structures.

This Method Statement provides detail of procedure adopted for the construction of backfilling behind structures and abutment.

Scope

This work will consist of backfilling behind abutment of bridges and around structures like foundations, underpass, box culvert and other similar structures in accordance with the requirements of these specifications (MoRT&H clause no. 305.4.4) and lines & dimensions shown in the drawing or as indicated by the Engineer.

Material

Approved material will be used as a backfill material from approved sources. Fill material shall be free from logs, stumps, roots, rubbish or any other ingredients likely to deteriorate or affect the structure.

Responsibility

Section In charge will be responsible for quality control of the section for the backfilling work. He will liaise with Concessionaire Engineer In Charge. Further he will be assisted by field Engineers, Surveyors, Supervisors and lab technicians.

Equipment

The following construction machineries will be deployed for backfilling work.

Dumper / trucks

Grader

Small Vibratory Roller

Water tanker

Plate Compactor

Procedure
- Backfilling around structures

Backfilling will be done with approved material after concrete or masonry is fully set and carried out in such a way as not to cause undue thrust on any part of the structure. All spaces between foundation, masonry or concrete and sites of excavation will be backfilled. Fill material will be spread in layers manually or by grader in layers of uniform thickness not exceeding 250mm compacted thickness over the entire width of the structure. Each layer of approved materials will be thoroughly compacted after necessary watering by means of small vibratory rollers/plate compactor or thoroughly rammed in small areas where mechanical means cannot be deployed. Successive layers will not be placed until the layers under construction have been thoroughly compacted to the specified requirement of table 300-2, i: e; 95% and 97% of MDD at OMC for embankment and sub grade respectively.

Backfilling Behind abutment and Wing wall

Filling behind abutments and wing walls for all structures without weep-hole, will be done with approved filling material. The fill material will be deposited in loose thickness and compacted after necessary watering up to a thickness of 250mm, until the required compaction of 95% & 97% of MDD at OMC achieved, for embankment & sub grade respectively. Filling will be carried out in equal layers on each side of the structures to avoid displacement and unequal pressure.

Where provision of any filter media is specified behind abutment (where weep-hole exists), filter media as designed will be laid and compacted after necessary watering up to a compacted thickness of 250mm until 95% & 97% of MDD at OMC achieved, for embankment & sub grade respectively. The material used for filter media will conform to the requirement for filter medium spelt out in clause 2504.2 / 309.3.2.

If impracticable to use conventional rollers, the compaction will be carried out by mechanical means like small vibratory roller/plate compactor. Care will be taken to see that, the compaction Equipment does not hit or come too close to any structural member, so as to cause any damage to them or excessive pressure against the structure.

Quality Control and Testing

Quality control tests shall be done as per Sl. no. 1 of Quality Control Tests and Acceptance Criteria

Safety & Environment

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

DETERMINATION OF DRY DENSITY OF SOILS IN PLACE (SAND REPLACEMENT METHOD)

Soil compaction is a artificial method in which expulsion of air from soil is done by mechanical means thereby increasing the density of soil In construction.
It is important to know and control the soil density during compaction process .To determine the proper soil compaction of embankment or subgrade in highway project , several methods were developed.The most prominent method is Sand Replacement method to check the relative density at site.In this article ,we will discuss in detail “how to perform sand replacement test at site”.

STANDARD USED

IS: 2720 (Part 28) 1974.

OBJECTIVE

To determine the in place dry density of natural or compacted fine and medium grained soils by sand replacement method.

APPARATUS

Small sand pouring cylinder for depth up to 150 mm.
Large sand pouring cylinder for depth more than 150 mm and not exceeding 250 mm.
Tools for excavating holes such as a scraper tool for leveling the surface, bent spoon or dibber for digging holes.
Cylindrical calibrating container with material diameter of 100 mm and an internal depth of 150 mm.
Balance of capacity 15 kg and sensitivity 1 gram.
A glass plate o about 600 mm square area and atleast 10 mm or more thicker.
Metal containers.
Metal tray having area 300 mm square , 40 mm deep with a 100 mm hole in the center of the tray.
1 mm and 600 microns IS sieves..
Clean, uniformly graded natural sand passing 1 mm sieve and retained on 600 microns sieve.

PROCEDURE

Calibration of Sand Pouring Cylinder

Clean and dry, sand passing 1 mm sieve and retained on 600 microns sieve approximately 5 to 6 kg for small pouring cylinder and 23 to 24 kg of sand for large pouring cylinder.
Remove the cap of the pouring cylinder.
Weigh the empty pouring cylinder (W).
Close the shutter of the cone.
Fill the sand in to the pouring cylinder about 10 mm below from the top.
Determine the net weight of sand in the cylinder (W1).
Now place the pouring cylinder on a clean plane surface, open the shutter and allow the sand to flow in to the cone.
Close the shutter when the flow stops.
Carefully collect and weigh (W2) the sand discharged from the pouring cylinder.
Refill the pouring cylinder with sand such that the initial weight is W1.
Place the pouring cylinder on the top of the calibration cylinder concentrically.
Open the shutter and allow the sand to flow in to the calibrating cylinder.
Close the shutter when the flow stops or no further movement of sand takes place in the cylinder.
Determine the weight (W3) of the pouring cylinder.
Repeat the above procedure for at least three times and determine the mean values of W2 and W3.
Determine the volume (V) of the calibrating cylinder either by measuring the dimensions
(Diameter and height) or by filling with water until the brim.

CALCULATIONS

Weight of sand (WS) in the calibration container up to level top

WS = W1 – W3 – W2 grams

Volume of calibrating container = V cc

DETERMINATION OF SOIL DENSITY

Prepare a flat approximately 450 mm square area with the aid of a scraper tool.
Place the metal tray just above the central hole on the prepared surface of the soil to be tested.
Excavate the hole in the soil with a chisel & hammer using the hole in the tray as a pattern to the depth of the layer to be tested.
Carefully collect the excavated soil from the hole and weigh (Ww).
Determine the water content (W) of the excavated soil as per IS: 2720 (Part 2) 1973.
Fill the pouring cylinder to the constant weight (W1) i.e. weight equal to the initial weight during calibration.
Remove the metal tray before the pouring cylinder is placed in position over the excavated hole.
Place the cylinder such that the base of the cylinder covers the hole concentrically.
Open the shutter and allow the sand to run out in to the hole.
Close the shutter of the pouring cylinder when no further movement of sand takes place in the cylinder.
Remove the cylinder and determine the net weight of sand (W4).

CALCULATIONS

REPORT

Report the bulk density and dry density of soil to the nearest second decimal.

PRECAUTIONS

Care shall be taken to see that the test sand used is clean, dry and uniformly graded.
Care shall be taken in excavating the hole to see that the hole is not enlarged against the side of the hole, as this will result in lower densities.
Care shall be taken to see that the same initial weight of sand is taken during calibration and during density measurement in the field.

PROCEDURE FOR QUALITY RECORDS

Quality records testifying to the satisfactory execution of project activities and quality objectives shall be legible, specify the work involved, properly maintained, readily retrievable, and available to authorized personnel.

In this procedure , we shall discuss in details pertaining to generating and maintaining the Quality Records for or by the construction.

1.GENERAL

Quality Records are documented evidence that construction conformed to requirements of contract as well as design specifications. Quality Records include:

Test and inspection reports
Monthly Reports
Material and equipment certificates required by specification
Equipment maintenance/preservation records
Acceptance and test data results
Non conformance’s
Corrective action ordered/taken
Audit reports
Project activity
Amount and type of material used
Frequency and accountability of submissions

Specified construction staff are liable for the preparation and maintenance of Quality Records. All records are identified as “Confidential” in accordance with specific procedures established by contract agreement.

2.PROCEDURE

Site Quality Manager

In coordination with the Site Execution Manager or the other group manager who receives or generates quality records, identify the quality records that will be retained during construction and identify the record custodian by job title.

In coordination with the client and other record custodians, define the Quality Records that are to be submitted to the client after completion of specified work or activity and identify this on the Standard Quality Records Control form.

The Site Quality Manager in coordination with the Site Manager will identify all Quality Records (or copies of records) that will be retained in the Records Retention center. Identify this on the Quality Control Records form.

Maintain all the Quality control Records form current and, if possible, before records are received on site or generated.

a.Custodian

Establish and maintain a file system for inspection, testing, and l Quality Control records system. The system shall ensure that records are easily available and protected.The system is to be identified on the Quality Records Control Form.

Before filing the record the custodian shall review the documents to verify the following:

Documents are appropriate
Documents are complete
Entries are correct – Documents are legible
Documents signed by authorized person

The custodian review the document with the originator or originator’s supervisor. Resolve any discrepancies with vendor documents through the purchasing department.

If any corrections required in the records to be accomplished by authorized personnel (i.e. record originator or originator’s supervisor) by entering the correct information and dating the change.

b.Turnover

Maintain the records until they are requested by project turnover and/or assigned to the Records Retention Center.

The Site Quality Manager will generate a checklist and verify that all required quality records have been completed and those designated for turnover are included in the Turnover Package.

All supporting documentation relating to completion will be retained by organization until system acceptance by Client. After system acceptance by Client, this documentation will be transferred to Client under separate correspondence.

PROCEDURE OF LAYING DRY LEAN CONCRETE

DRY LEAN CONCRETE is cement concrete with low slump as well as low cement which is being laid as a first layer for rigid pavement over sub-base (GSB) , rolled & compacted by mechanical means.We will discuss with all sections one by one as per following order:

GENERAL
REFERENCE
EQUIPMENT WITH ESSENTIAL FEATURES
MANPOWER REQUIREMENTS
MATERIALS
TRIAL STRETCH
QUALITY CONTROL TESTING & ACCEPTANCE
SAFETY REQUIREMENTS /MEASURES

1.GENERAL

This work should be carried out accordance with the wants of Contract Specifications and in conformity with the lines, grades , drawings or as directed by the Engineer. The work will include furnishing of all plant and equipment, materials , labour and performing all operations, in reference to the work as approved by the Engineer.
The design parameters of dry lean concrete , if any will be as stipulated in the contract drawings.

2. REFERENCE

i) Clause 600 of MORT&H – 5th Edition
ii) IRC:SP: 49-2014
iii) IS: 16714-2018
iv) Relevant Approved Drawings

3. EQUIPMENT WITH ESSENTIAL FEATURES

i) Batching Plant
ii) Paver with Electronic Sensor
iii) Dump Trucks
iv) Water Tanker
v) 8-10 Tonne Roller
vi) Hand Tools: Shovels, Broom, Wire brush, Straight edge
vii) Testing Equipment’s: 20 cm dia Density cone, Vibrating Hammer, Cube Moulds, Thermometer.

4. MANPOWER REQUIREMENTS

i) Site Engineer
ii) Surveyor (With Team)
iii) Operators, Supervisors and Laying Team

5. MATERIALS

5.1 Source of Materials

Source the approval of material should be obtained from the Engineer at least 45 days before the scheduled commencement of the work. If later it is proposed to obtain the materials from a different source, Engineer will be notified for his approval at least 45 days before such materials are to be used.

5.2 Cement

Following sorts of cement could also be used with prior approval of the Engineer.
Ordinary Portland Cement 53 Grade IS:8112 Cement to be used may rather be obtained in bulk form. It will be stored in accordance with stipulations contained in Clause 1014.

5.3 Ground Granulated Blast Furnace Slag

GGBS should be used from approved source & complying the requirements of IRC SP: 49-2014

5.4 Aggregates

Aggregates for lean concrete will be crushed material complying with IS: 383. The aggregates will not be alkali reactive. The limits of deleterious materials will not exceed the requirements set out in IS: 383.

a)Coarse aggregate

Coarse aggregates will consist of clean, hard, strong, dense, non-porous and durable pieces of crushed stones or crushed gravel . The maximum size of the coarse aggregate will be 26.5 mm. The water absorption of coarse aggregate shall not exceed 3%.

b)Fine aggregate

The fine aggregate will consist of clean, natural sand or crushed stone sand or a combination of the two and will conform to IS: 383. Fine aggregate will be free from soft particles, clay, shale, loam, cemented particles, mica, organic and other foreign matter. The water absorption of coarse aggregate shall not exceed 3%.
The material after blending will conform to the grading as indicated in Table -1 of IRC SP 49-2014

5.5 WATER
Water used for mixing and curing of concrete will be clean and free from injurious amounts of oil, salt, acid, substance or other substances harmful to the finished concrete. It will meet the requirements stipulated in IS: 456.

5.6 Proportioning of Materials for the Mix

The mix will be proportioned with a maximum aggregate cement ratio of 14:1. The water content will be adjusted to the optimum as per Clause 4.2 of IRC SP 49 for facilitating compaction by rolling. The strength and density requirements of concrete will be determined in accordance with Clause 7.1 of IRC SP 49-2014 by making trial mixes.

5.7 Cement Content

The minimum cementitious content in the lean concrete will not be less than 140 kg/cum. of concrete. If using GGBS minimum cement content shall not be less than 100 kg/m3.If this minimum cement content is not sufficient to produce concrete of the specified strength, it will be increased as necessary to obtained the strength.

5.8 Concrete strength

The average compressive strength of each consecutive group of 5 cubes made in accordance with IR: SP:49-2014 will not be less than 7 MPa at 7 days. In addition, the minimum compressive strength of any individual cube will not be less than 5.5 MPa at 7 days. The design mix complying with these requirements shall be worked out before start of work.

5.9 Sub-grade

The sub-grade will conform to the grades and cross sections shown on the drawings and will be uniformly compacted to the design strength in accordance with these specifications and specification stipulated in the contract. The lean concrete sub-base shall not be laid on a poor sub-grade , if any must be properly back-filled and compacted as per specification. As far as possible, the construction traffic will be avoided on the prepared sub-grade. A day before placing of the sub-base, the sub-grade surface will be given a light sprinkling of water and rolled with one or two passes of a smooth wheeled roller after a lapse of 2-3 hours in order to stabilize loose surface and then check for compliance.

5.10 Construction

The pace and program of the lean concrete sub-base construction will be matching suitably with the program of construction of the cement concrete pavement over it. The sub base will be overlaid with cement concrete pavement only after 7 days after sub-base construction.

5.11 Batching and mixing

The batching plant will be capable of proportioning the materials by weight, each type of material being weighed separately. The cement from the bulk stock will be weighed separately from the aggregates. The capacity of batching and mixing plant should be at least 25 % higher than the proposed capacity for the laying arrangements & batching and mixing plant should have necessary automatic controls to ensure accurate proportioning and mixing. Other types of mixers will be got approved subject to demonstration of their satisfactory performance during the trial length.

6.0 Trial Stretch

A trial stretch shall be made to the required width and minimum of 60 metre length . The trial length shall contain construction of at least one transverse construction joint involving hardened concrete and sub-base to be laid subsequently, so as to demonstrate the soundness of the procedure. In one day not more than 30 m of trial stretch shall be laid. The in-situ density of the freshly laid concrete shall be determined by sand replacement method by making 3 density holes at equal distances that diagonally bisects the trial length, these shall not be made in the strip of 500 mm from the edges. The average of these shall be considered as 100%, and with this the field density of the regular work shall be compared. The hardened concrete may be cut for 3m width in the trial length and reversed to check the bottom surface for any segregation or honey-combing, if found necessary adjustments shall be made in the mix design.

6.1 Transportation and placing

The plant mix concrete shall be transported by sufficient number of trucks to ensure continuous, uniform supply of concrete to feed the laying Equipment. The mix shall be protected from the weather, by covering the tippers/dumpers with tarpaulin during the transit. The lean concrete shall be laid to the required widths, grades,camber and thickness with self-propelled, electronic sensor or mechanical paver.

The Equipment shall be capable of laying the materials in an even manner without segregation, to the specified thickness after the compaction. The paving machine should have facilities to give good initial compaction.

6.2 Compaction

The compaction shall commence as soon as the concrete laid and levelled to the full width till there is no further movement under the roller and the surface is closed. In addition to the number of passes required for compaction, there shall be a pass without vibration as preliminary pass and another at the end as final pass. The minimum dry density obtained shall be 97% of that achieved in trial length, and at a distance of 500 mm from edge it shall be 95% of that achieved in the trial length. The finished surface should be inspected immediately, and all loose, segregated or defective areas if any ,shall be corrected by using fresh lean concrete. Honeycombed areas, any level/ thickness deficiency and surface irregularities shall be corrected by concrete with 10 mm and down aggregates. Special care and attention shall be exercised during compaction near joints, kerb, channels, side forms, around gullies and manholes.

7.0 Quality Control Testing and Acceptance

Curing

As soon as the lean concrete surface is completed, curing shall commence.

a) Curing shall be done by covering the surface by hessian cloth in two layers which shall be kept continuously moist for 7 days by sprinkling water.

b) If water-curing is not possible, the curing shall be done by spraying with liquid curing compound. The curing compound shall be white pigmented type with water retention index of minimum 90 percent, when tested in accordance with the test method given in Annexure-A of IRC SP 49 -2014 To check the efficiency of the curing compound, the supplier shall be required to provide the test certificate from a recognized laboratory. Curing compound shall be sprayed immediately after when rolling is complete & the surface shall also be covered with wet hessian for three days.

2)Tolerance

The tolerances for thickness shall be ± 10 mm.

3)Density

The dry density of the laid material shall be determined from density holes at locations equally spaced along a diagonal that bisects each 2000 sq.m or part thereof, of material laid each day. It shall not be less than 97% of design density .The control of strength shall be exercised by taking samples of dry lean concrete for making cubes at the rate of 3 samples for each 1000 sq.m or part thereof laid each day. The cube samples shall be compacted, cured and tested in accordance with IS: 51 6.

8.Safety Requirements/Measures

DLC laying team will wear personal protective equipment while producing, transporting and laying the mix. All safety measures will be taken as per approved plan.

HIGHWAY ENGINEER INTERVIEW QUESTION AND ANSWER

There are so many mails received by viewer’s or visitor of my site to provide a clear idea how to face interview for a highway engineer.

First of all , keep in mind employers wish to hire people that are confident in their interviews.But how do they judge this? and what are the simplest ways to point out confidence in an interview so you’ll get hired faster?
Here are the some best questions and answers which is usually asked during interview from highway engineer in any good organization.Hope it will be fruitful to you .

Q 1. Tell me about yourself?

Ans: “Hello, my name is XYZ. I am a professional with a degree/diploma in Civil Engg in 20xx. My qualifications include xyz years of experience in infrastructure project especially in Highway Project & deals with execution aspect.I started my carrier with building project with XXX (Name of First company ) as a Diploma I Degree Trainee Engineer and after that gone to YYY {Name of second company) Site Engineer; after 2017 I engaged in highway project and joined in ZZZ (Name of third company) as Highway Engineer & successfully completed xyz National /State highway project.

At present, I am responsible for raising RFI, making bed of Soil/GSB/WMM , maintain strip chart according to progress,planning for the next day prorgramme and follow the instruction my seniors & do the whatever job assigned to me.

Q 2.What types of pavement is there?

Ans: Flexible /Rigid pavement.

Q 3.What is the crust thickness of pavement in your project?

Ans:650 mm(GSB 250 mm,CTB 200 mm,WMM (Crack Relief Layer)100 mm, DBM 50 mm & BC 50mm). For service road 330 mm- CTGSB 180 mm , WMM 100 mm (Crack relief layer )& BC 50 mm.

Q 4. How much quantity of Earth work, GSB, WMM & Bituminous work is there?

Ans: Earth Work -3000000 m³, GSB 200000 m³, CTB 170000³ ,WMM 100000 m³ & DBM/BC 140000m³ or whatsoever in your project.

Q 5.What is difference between Flexible Pavement & Rigid pavement?

FLEXIBLE PAVEMENT

Deformation in the sub grade is transferred to upper layers.Have low flexural strength.
Have low completion test but high repairing cost.
Damaged by oil and chemicals.
Design Based on load distribution factor

RIGID PAVEMENT

Deformation in the sub grade
is transferred to subsequence Layers.
Have high flexural Strength.Have low repairing cost but high completion cost.
No damage by oil or Greece.Design based on Flexural strength or slab action

Q 6 .How much staff is working under you , draw the organization chart & show your position ?

Ans: 4 staffs are working under me and draw the Organization chart on your own , show your position.

Q 7.Who is your consultant/IE ?

Ans : The name of my consultant/IE is xyz.

Q 8 .what is the name of Your IE Team Leader ?

Ans: The name of my consultant/IE Team Leader is Mr/Sri xyz.

Q 9.What is difference between OGL & NGL?

Ans:The first level taken of the natural ground without using any mechanical means is called NGL whereas the level taken after preparation of bed by using mechanical means Grader ,Doze, JCB & Roller is called OGL.

Q 10.What do you know about this company?

Ans:As being an experienced candidate in this sector I’ve heard a lot about your organization.Your organization’s fame and prestige is what drove me here to apply for the position when your job vacancy was posted on your site. I know that your company has been in business for over xyz years, with an excellent reputation in successful completion of highway project .Your company is providing good opportunities to new coming member owing to that I am sitting infront of you.

Q 11.Why dowel bar is being provided PQC pavement?

Ans: Dowel bars are required at expansion joints to transfer wheel loads to the adjacent slab. It is provided in the wheel paths only, it links the two adjacent structures by transferring loads across the joints.

Q 12.What is land width of shoulder in plain & rolling terrain?

Ans : Land width of shoulder will be either 2.0 m or 3.5 m depending upon the situation.

Q 13.What do you understand by Sub-base & base course in flexible pavement ?

Ans : Sub – base course is the first layer which is constructed immediately after the subgrade after the subgrade such as GSB & WBM etc.Base course is sandwich layer between wearing course and sub-base course.Base can have multiple layer such as CTB & WMM etc.

Q 14.What is the vertical clearance of LVUP VUP & CUP?

Ans : The vertical clearance of VUP,LVUP and CUP are 5.5 m,3.5m and 3.0 m simultaneously.

Q 15. What is the Minimum Right of way should be available (ROW) for 4 laning & 6 laning project?

Ans: A minimum Right of Way (ROW) of 60 m should be available for development of a 4 laning and 6 laning project as per IRC SP 84-2014 and IRC SP 87-2013.

Q 16. What is the role of tie bar?

Ans :Tie bar is placed across longitudinal joints at the mid-depth of the slab .It prevent lanes from separation and differential deflections & transverse cracking These are installed by providing appropriate chair or these are installed by providing appropriate (drilled) holes in the side forms depending on the size and spacing of bars. Generally 16 mm dia bar is being used.

Q 17.What is the role of joint sealant?

Ans : It seals the joint width and prevents water and dirt from entering the joint which causing dowel bar corrosion and unexpected joint stress resulting from restrained movement.

Q18.What is the minimum relative percentage compaction requirement for embankment and subgrade ?

Ans: For embankment 95% & for subgrade 97 % relative compaction is required.

Q.19. What is the role of PVC dowel sheet ?

Ans :It serves to facilitate the movement of dowel bar.On one side of the joints,the dowel bar is encased in concrete.On the other side, however, the PVC dowel sleeve is bonded directly to concrete so that movement of dowel bar can take place.

Q 20 Tell the level tolerance in Subgrade (For flexible Pavement) ?

Ans; Sub grade +/- 20 mm.

Q 21.What is bumping or pumping in subgrade & why occur?

Ans: A bumping/pumping in subgrade is similar to the concept to trying to compact something on matress means when soil compactor rolls over a prepared subgrade soil . it got compacted with staggered line but when roller cross over, soil returns to its original position . This type of phenomena occurs when excess moisture is present in the prepared bed.

Q 22.What do you understand by carriage way?

Ans: It is the width of the road which is used by the traffic for moving on it.It is generally central portion of the total land width and is paved and surfaced with the bituminous concrete for service to the road users.

Q 23 .What is hard shoulder?

Ans:The hard shoulder is the area at the side of a motorway or other road where we are allowed to stop if our car breaks down.It is generally separated by white line.

Q 24. Why the saw cut joint is provided in road kerb?

Ans: Saw cut helps control cracking occurs due to shrinkage in Kerb.

Q 25. What is the role of separation member in Rigid Pavement?

Ans: The separation membrane between concrete pavement slab and sub-base has mainly 4 function:

It avoids the possibility of active aggressive agents from soil water being attached to the concrete slab.
It prevents the loss of cement and water in immature concrete which significantly affects the strength and durability of hardened concrete.
It reduces friction between concrete and sub-base.
It avoids the mixing up of sub-base materials and freshly placed concrete.

Q 26. What is the median width in raised condition in plain & Mountainous and Steep terrain?

Ans: In plain area generally 5.0 m but in built up area 2.5 m.In mountainous & steep terrain it is always 2.5 m.

Q 27. What is minimum bitumen content in DBM & BC for grade 1?

Ans ; DBM 4.0 % & 5.2%

Q 28.Tell me the difference between Slope and Camber?

Ans : Slope is an area of ground that tends evenly upward or downward while camber is a slight convexity, or curvature of a surface of the road , so that water will flow off the sides .Camber is the transverse slope provided to the road surface for the drainage of the rainwater for the better performance of the road. Camber can be written as 1 in n or x%.

Q 29. What is the reason for rutting?

Ans: There are 5 main reason for rutting

Heavy traffic axle.
High temperature & using VG30 bitumen.
Higher bitumen content.
More fines.
Less air voids in bituminous surface.

Q 30. For how many period flexible pavement design should be done?

Ans; Flexible pavement shall be designed for a minimum design period of 15 years or operation period, whichever is more.

Q 31. For how many period rigid pavement design should be done?

Ans; Rigid pavement shall be designed for a minimum design period of 30 years or operation period, whichever is more.

Q 32. ln tack coat & Prime coat which type of emulsion is used as per MORT&H 5^th revision?

Ans; In tack coat RS1 & in prime coat SS1

Q33.How much minimum longitudinal slope is required for lined drains and unlined drains ?

Ans: As far as possible, longitudinal slope shall not be less than 0.3 percent for lined drains and 1.0 percent for unlined drains.

Q 34. What should roughness Index be of finished wearing course?

Ans: Not more than 2000 mm/km for each lane in a km length.

Q35.What will the minimum thickness of bituminous overlay for pavement strengthening ?

Ans: The thickness of bituminous overlay for pavement strengthening shall not be less than 50 mm bituminous concrete after attending to the requirements of profile corrective course.

Q 36. What is the advantage of Cement Treated Base ?

Ans: There are so many advantages of using CTB :

CTB provides a durable, long-lasting base in all types of climates.
Can speed up the Project Completion
Can reduced thickness of pavement.
Reduced Project Cost (approx. 8 to 10 thousand rupees per metre)
Reduced consumption of aggregate.
Reduced consumption of bitumen.

Q 37. What will be the cross fall on straight sections of road carriageway, paved shoulders of bituminous surface and paved portion of median for concrete surface in National Highway project?

Ans:The cross fall on straight sections of road carriageway, paved shoulders and paved portion of median will be 2.5% for bituminous surface and 2.0% for the cement concrete surface.

Q 38. What is the justified minimum design speed for service road ?

Ans: A minimum design speed of 40 km/h shall be adopted for service roads.

Q 39. In open country, on what space median openings shall be provided?

Ans: In open country, median openings shall not be spaced closer than 2 km. Additional controlled openings can be provided for inspection and diversion of traffic during repair and rehabilitation.

Q 40. In built area, on what space median openings shall be provided?

Ans; In built up area, median opening shall be provided as per site requirement and the spacing between two medians opening in built up area shall not be less than 500 m.

Q 41.As per IRC what is the minimum dia of new pipe culvert, cushion & class to be used in National Highway?

Ans: As per IRC SP 84-014 minimum dia of new pipe culvert should not be less than 1200 mm & pipe should be NP4 pipe. Minimum depth of earth cushion over pipe excluding road crust shall not be less than 600 mm for new,reconstructed and retained culverts constructed in National Highway projects.

Q 42.What is the output of excavator having 1 m3 bucket?

Ans : 60 m3 /hour

Q 43. Why the mastic is being provided on deck slab ?

Ans: In most cases the protective layer is a Mastic Asphalt layer. This layer also serves as a second waterproofing layer. The non-porous mastic asphalt is usually used for the protective layer of the bridge pavement.

Q 44.What is your weakness?

The first is my inability to share responsibilities.
I lose my patience when I suspect that the other person isn’t doing it right. I’ve discussed these weaknesses with my supervisor as areas I’d like to improve.
The third is I easily trust on anyone.

Q 45. Why you want to leave your present company?

Ans : You can tell any of the following points:

I would really love to be part of your project from beginning to end, and I know I’d have that opportunity here.
In my current role, I’ve learned many new skills. I’m looking for a position in which I can continue to grow that skill set in new circumstances.”
I’ve learned a lot in my current role, but I’m looking for an opportunity that provides more challenges as I continue developing my skills and abilities.”

Q 46.Tell me your 5 strong point?

Ans: Tell the following points with cleverness:

Flexibility to handle any situation.
Good Communication.
Work under pressure.
Dedication.
Honesty

Q 47.Tell me your achievement in your carrier?

Ans: Tell any of the below point confidently:

Re-organized something to make it work better
Identified a problem and solved it
Come up with a new idea that improved things
Developed or implemented new procedures or systems
Worked on special projects
Received awards/Certificates

Q 48.What is your salary expectation?

Ans; This is your most important negotiation. Never tell lie about what you currently having, but feel free to include the estimated cost of all your fringes, which could well tack on 25 -30% more to your present “cash-only”salary.

Q 49 .How much time you required to join?

Ans: Always says one month but handle this situation very calmly, if you are ideal & have no job, can say within 7 days.

HOW TO CONVERT 1:2:4 FROM VOLUME TO WEIGHT

A frequent question arriving in my email mailbox is “HOW TO CONVERT 1:2:4 FROM VOLUME TO WEIGHT ?” Most commonly, people are trying to find out how to convert from volume to weight so in this article I am giving detail procedure for to convert from weight to volume.

For clarification I am taking table 9 from IS 456-2000

HOW TO CALCULATE

Calculation of materials required for 1 m³

Density of Cement = 1440 kg/cum

Volume of 01 bag (50 kg) of cement = 50 /1440 = 0.035 cubic meter (cum)

We know the ratio 1:2:4

Volume of Sand required would be = 0.035*2 = 0.07 cubic meter (cum)

Volume of Aggregate required would be = 0.035*4 = 0.14 cubic meter (cum)

Next step , you have to convert the volume and check for the feasibility from IS 456-2000 provision means water cement ratio maximum 32/50 =0.64 and all ingredient(coarse aggregate fine aggregate should not be more than 330 kg.

CONVERT VOLUME TO WEIGHT

For converting volume to weight you need dry loose bulk density , which can be determine by density box. Here we are assuming For sand 1450 kg/m³ and for aggregate take 1550 kg/m³.

Quantity of sand will be 0.07 x 1450 = 101.50 kg

And quantity of aggregate 0.14 x 1550 =217.0 kg

Cement =50 kg

And take W/C ratio 0.60 Water 0.60 X 50 = 30.0 kg but specified water is 32 kg hence O.K.

Specified All in aggregate should not be more than 330 kg(318.0 kg), hence O.K

So, One bag of cement (50 Kgs) has to be mixed with 101.50 kgs of Sand, 217.0 Kgs of aggregate and 30 kgs of water to produce M15 grade concrete.

MATERIAL REQUIRED FOR I M³

From the above calculation, we have already got the weights of individual ingredients in concrete . So, the weight of concrete produced with1 Bag of cement (50 Kgs)

=50 kg + 101.5 kg + 217 kg + 30.0 kg = 398.5 kg say 400 kg

Considering concrete density = 2400 kg/cum,

One bag of cement and other ingredients can produce = 400/2400

= 0.1667 m³ of concrete (1:2:4)

01 bag cement yield = 0.166 cum concrete with a proportion of 1:2:4

01 cum of concrete will require Cement required = 1/0.166 = 6.02 Bags Say 6 bags

Sand required = 101.5/0.166 = 611.44 Kg or 611 kg

Aggregate required = 217/0.166 = 1307.28 kg or 1307 kg

Water =30.0/0.166= 180.72 say 181 kg

INGREDIENT REQUIRED FOR 1:2:4 IN 1 M³ IN Kg

Cement 300.0 kg
Sand 611.0 Kg
Aggregate 1307.0 Kg
Water 181.0 kg
If ratio of 20 mm & 10 mm is 60% and 40%
Then 20 mm 1307 x 60%= 784 kg
10 mm 1307 x 40%=523 kg
In the same manner you can calculate for M20

DOCUMENT CONTROLLING PROCEDURE

Documentation relating to all project activity is prepared and maintained by
each organizational element. Such documentation will provide accurate and
current information on all project activities and for all information which contributes to the understanding of the project. Records are reviewed by appropriate personnel and provided to all concerned organizational elements. Procedure for documentation and record maintenance and retention are given as below:

1. SUMMARY
1.1. This procedure defines the requirements for the creation, review, approval, distribution, use and revision of quality management system documents.
1.2. This procedure applies only to documents which instruct office/site staff on how to carry out activities and tasks; this includes manuals, procedures, forms and instructional sheets or posters.
2. PROCEDURE
2.1. Creation of Documents
2.1.1. Documents are created by an appropriate subject matter expert.
2.1.2. All internal documents are created as soft files (MS Word®, etc.); it is recommended that files of a similar type follow the format of other documents in that type.
2.1.3. Draft versions must then be sent to the appropriate approver(s) for review and approval.
2.1.4. Original releases of documents are given a revision indicator of “0”.
2.2. Review and Approval
2.2.1. The Quality Manual may only be approved by the senior Management. Other documents are to be approved by the original author, or a company executive.
2.2.2. Draft files may be sent to the approver(s) via hard copy or e-mail.
2.2.3. The reviewer will resolve any issues with the original author to achieve a satisfactory document.
2.2.4. The reviewer will indicate approval of the document by e-mail.
2.2.5. The approved document shall then be forwarded to the Document Controller .
2.2.6. If hard copy binder will be used , document Controller , will maintain a binder of most current hard copy versions of documents.
2.2.7. The Document Controller will maintain a computer folder, on the company server, for the latest soft copy versions of document with backup facility. The Document Controller Title will place new or revised documents into that folder, Any previous soft versions are then moved to a separate folder identified for obsolete documents which are kept for historical purposes.
2.2.8. The directory of official released documents shall act as a “master list” of documents, indicating the setting each file’s permission to READ ONLY, or converting the released versions to a non-editable file format.
2.2.9. current versions of all documents. No other master list is required.
2.3. Distribution of Documents
2.3.1. If intranet is used, Controlled documents will be available via the intranet for all employees.
2.3.2. If hardcopy document distribution is used, the Document Controller will maintain a list of where controlled hardcopy documents are to be distributed. The Document Controller will be responsible for distributing updated copies of such controlled hardcopies to proper locations. Controlled hardcopies shall be marked with stamp in color ink on the first page as CONTROLLED, to distinguish them from uncontrolled documents or photocopies.
2.3.3. Controlled hardcopies may not be altered or modified by users, and must remain legible and readily identifiable. This includes hand mark-ups by unauthorized personnel. Controlled hardcopies may not be photocopied, unless for the purposes of sending to a recipient who is authorized to receive uncontrolled versions of Project documents (i.e., a vendor or customer).
2.4. Re-Evaluation
2.4.1. Documents must be reviewed by the original author or another subject matter expert or top manager as required.
2.4.2. The Document Controller will ensure re-evaluation is conducted and that documents are updated if required. The Document Controller will maintain a record of document re-evaluations of any process, to identify when documents are due for re-evaluation.
2.4.3. If a document is determined to require updating, the changes shall be made and a new version issued per the rules below.
2.4.4. If a document is determined not to require updating, no action on the document is necessary.
2.5. Revising Documents
2.5.1. Changes to documents go through the same steps as original issue, except that their revision level is advanced upon approval.
2.5.2. Only authorized personnel may change documents, although any employee can request a change to their Manager, or other document change request form. All the revised document shall include a change history table within its text.
2.5.3. Any changes to documents require authority review and approval shall be submitted accordingly, and not implemented until such approval is obtained.
2.5.4. If document changes require regulatory approval prior to implementation, this will be obtained in writing & reflect the reason for the change.
2.5.5. Re-evaluation, inspection (where applicable) and internal auditing will confirm the effectiveness of changes.
2.6. Controlling Documents of External Origin
2.6.1. For external documents such as standards or third party specifications which are referenced in a customer purchase order or contract, these documents may be maintained without control.
2.6.2. For external documents such as standards or third party specifications which are not referenced in a customer purchase order or contract, these must be controlled. Such control requires that the Document Controller or responsible manager obtain the latest version of the document, and maintain it on the company server (for electronic versions) or in a binder of controlled external documents (for hardcopies). Like other controlled documents, these may not be edited or copied.
2.6.3. Third party specifications and prints, including those of the customer, are controlled per the configuration management requirements set forth in the Quality Manual .
2.6.4. External documents for non-critical use, such as user manuals, reference books, marketing materials, and supplier directories are not controlled.
2.7. Forms
2.7.1. Forms are a special kind of document that may be photocopied as needed. A softcopy of each approved form should be sent to document controller for his record for inclusion in the Document Master List .