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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.

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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

  1. Small sand pouring cylinder for depth up to 150 mm.
  2. Large sand pouring cylinder for depth more than 150 mm and not exceeding 250 mm.
  3. Tools for excavating holes such as a scraper tool for leveling the surface, bent spoon or dibber for digging holes.
  4. Cylindrical calibrating container with material diameter of 100 mm and an internal depth of 150 mm.
  5. Balance of capacity 15 kg and sensitivity 1 gram.
  6. A glass plate o about 600 mm square area and atleast 10 mm or more thicker.
  7. Metal containers.
  8. Metal tray  having area 300 mm square , 40 mm deep with a 100 mm hole in the center of the tray.
  9. 1 mm and 600 microns IS sieves..
  10. Clean, uniformly graded natural sand passing 1 mm sieve and retained on 600 microns sieve.

PROCEDURE

Calibration of Sand Pouring Cylinder

  1. 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.
  2. Remove the cap of the pouring cylinder.
  3. Weigh the empty pouring cylinder (W).
  4. Close the shutter of the cone.
  5. Fill the sand in to the pouring cylinder about 10 mm below from the top.
  6. Determine the net weight of sand in the cylinder (W1).
  7. Now place the pouring cylinder on a clean plane surface, open the shutter and allow the sand to flow in to the cone.
  8. Close the shutter when the flow stops.
  9. Carefully collect and weigh (W2) the sand discharged from the pouring cylinder.
  10. Refill the pouring cylinder with sand such that the initial weight is W1.
  11. Place the pouring cylinder on the top of the calibration cylinder concentrically.
  12. Open the shutter and allow the sand to flow in to the calibrating cylinder.
  13. Close the shutter when the flow stops or no further movement of sand takes place in the cylinder.
  14. Determine the weight (W3) of the pouring cylinder.
  15. Repeat the above procedure for at least three times and determine the mean values of W2 and W3.
  16. Determine the volume (V) of the calibrating cylinder either by measuring the dimensions
  17. (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

  1. Prepare a flat approximately 450 mm square area with the aid of a scraper tool.
  2. Place the metal tray just above the central hole on the prepared surface of the soil to be tested.
  3. 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.
  4. Carefully collect the excavated soil from the hole and weigh (Ww).
  5. Determine the water content (W) of the excavated soil as per IS: 2720 (Part 2) 1973.
  6. Fill the pouring cylinder to the constant weight (W1) i.e. weight equal to the initial weight during calibration.
  7. Remove the metal tray before the pouring cylinder is placed in position over the excavated hole.
  8. Place the cylinder such that the base of the cylinder covers the hole concentrically.
  9. Open the shutter and allow the sand to run out in to the hole.
  10. Close the shutter of the pouring cylinder when no further movement of sand takes place in the cylinder.
  11. 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

  1. Care shall be taken to see that the test sand used is clean, dry and uniformly graded.
  2. 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.
  3. Care shall be taken to see that the same initial weight of sand is taken during calibration and during density measurement in the field.

 

 

 

 

 

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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.

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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:

  1. GENERAL
  2. REFERENCE
  3. EQUIPMENT WITH ESSENTIAL FEATURES
  4. MANPOWER REQUIREMENTS
  5. MATERIALS
  6. TRIAL STRETCH
  7. QUALITY CONTROL TESTING & ACCEPTANCE
  8. 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

  1. 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.

 

 

 

 

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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

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

RIGID PAVEMENT

  1. Deformation in the sub grade
  2. is transferred to subsequence Layers.
  3. Have high flexural Strength.Have low repairing cost but high completion cost.
  4. 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:

  1. It avoids the possibility of active aggressive agents from soil water being attached to the concrete slab.
  2. It prevents the loss of cement and water in immature concrete which significantly affects the strength and durability of hardened concrete.
  3. It reduces friction between concrete and sub-base.
  4.  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

  1. Heavy traffic axle.
  2. High temperature & using VG30 bitumen.
  3. Higher bitumen content.
  4. More fines.
  5. 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 5th 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 :

  1. CTB provides a durable, long-lasting base in all types of climates.
  2. Can speed up the Project Completion
  3. Can reduced thickness of pavement.
  4. Reduced Project Cost (approx. 8 to 10 thousand rupees per metre)
  5. Reduced consumption of aggregate.
  6. 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?

  1. The first is my inability to share responsibilities.
  2. 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.
  3. 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:

  1. I would really love to be part of your project from beginning to end, and I know I’d have that opportunity here.
  2. 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.”
  3. 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:

  1.  Flexibility to handle any situation.
  2. Good Communication.
  3. Work under pressure.
  4. Dedication.
  5. Honesty

Q 47.Tell me your achievement in your carrier?

Ans: Tell any of the below point confidently:

  1. Re-organized something to make it work better
  2. Identified a problem and solved it
  3. Come up with a new idea that improved things
  4. Developed or implemented new procedures or systems
  5. Worked on special projects
  6. 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.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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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
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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 .

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HOW TO CURE CONCRETE CUBE

As all over the world concrete is accessed by its compressive strength so curing of concrete cube in a proper manner having great importance .Concrete cube can be cured in a following manner:

  1. Leave the test specimens in the mould for at least 16 h, but not longer than three days, from the time of addition of water to the dry ingredients. Protect the specimens from shock, vibration and water evaporation. Store the specimens at a temperature of 27 ± 3 °C.
  2. After removal from the mould, submerge the test specimens in clean, fresh water immediately. Store the test specimens in water at a temperature of 27±2°C and take it out just prior to testing. Alternately, store the test specimens in a chamber at a temperature of 27 ± 2°C and a relative humidity of at least 95 percent until just before testing.
  3. If the test specimens are to be sent to a test laboratory, cover the test specimens with wet cloth or wet sand/ sawdust or other suitable material or seal the test specimens in plastic bags containing water to ensure that the test specimens are delivered to the test laboratory in damp condition not less than 24 h before the time of testing. At the test laboratory, store the test specimens in water at a temperature of 27 ± 2°C until taking it out just prior to testing.
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Calibration Procedure Of Equipment

  1. SUMMARY
    • The aim of this procedure is to define the necessity for calibration or verification of equipment which can be used to determine the acceptability of product.
    • The QA/QC Head will be responsible for implementation and management of this procedure.
  1. PROCEDURE: CALIBRATION
    • Devices subject to calibration shall be calibrated by an approved outside service provider, or by trained employees.
    • Third party calibration laboratories should be accredited to NABL whenever possible, as this provides the best control of calibration activities, and traceability to national standards.
    • When staff perform in-house calibration, this shall be performed in accordance with documented procedures for each & every type of calibration performed.
    • Traceability to the national standards should be maintained for all devices where such traceability is possible .
    • Approved calibration service providers should maintain suitable environmental conditions for calibration such as temperature and relative humidity on any calibration test certificates. For in-house calibration, the QA/QC head will ensure suitable conditions for calibration.
    • The Calibration log will be maintained by the QA/QC Engineer. This document will contain the list & make of all devices with serial number, date of last calibration, and next calibration due date. All calibrated certificates must have the identification of any standards used by the calibration house, and their serial numbers, allowing for traceability to Client/ Independent Engineer.
    • For tools calibrated in-house by EPC contractor staff, the results and standards used shall be recorded on the Calibration Record and shall include any standards and/or procedures uses.
    • Calibrated devices should contain a calibration sticker that includes the current calibration status, calibration due date, and device identification number. Where the device cannot accommodate a calibration sticker due to size or frequency of use, the device shall be numbered and the QC Manager shall keep a log of those devices and their status.
    • QC Manager shall submit expired tools to QC Head for recalibration, and he shall positively recall such expired tools for recalibration.
    • An “amnesty window” of 1 week is allowed beyond the due date marked on the device, to accommodate arrangement of calibration or verification, or for production capacity purposes.
    • Devices in use for noncritical measurements are to be marked REFERENCE ONLY.
    • Any device failing to satisfy calibration standards will immediately be taken out of service. The device may then be sent out for repair. Repaired devices must be calibrated before being returned to service.
    • When a measuring device is found to be out of tolerance, and/or reported on the calibration certificate of having been found as “defective” or “out of tolerance” by the third party provider, QC Manager shall be notified immediately. The QC Head shall oversee a study to find out the impact of the out-of-tolerance device on product shipped.
  2. VERIFICATION
    • Where a device cannot be calibrated against traceable standards, it must be verified against some known-good object or method and proven as acceptable.
    • Known-good objects must be protected so their status is not altered, either by physical damage or deterioration.
    • Known-good methods must be documented in procedures, with a rationale for their acceptability being documented.

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DESIGN CONTROL PROCEDURE

1.SCOPE: This procedure identifies design processes that require process control.

2.SUMMARY: The design control is essentially intended for controlling all activities of design planning, design preparation, verification , review and validation so that the final product meet specified requirements .

3.DIFFERENT STAGES OF DESIGN : Following activities covering the different stages of the project:

  • Traffic Survey
  • Inventory and Condition Survey Of Road , Bridges and Culverts
  • Topographic Survey
  • Axle Load Survey
  • Benkleman Beam Deflection Test , If Required.
  • Soil and Material Investigation.
  • Geo-Technical and Sub Soil Investing.
  • Checking , Approval and Filling of Calculation.
  • Review , Approval , checking & verification of Design Outputs.
  • Control of design changes and validation of design.

4.PROCEDURE :

  1. All the activities of project design has been undertaken by ………authorized consultant.
  2. After going through all the procedure above mentioned, the design consultant will submit the design report to the concessionaire.
  3. Concessionaire shall review the design for the suitability & project specific requirement.
  4. If found suitable, analyse the cost calculation and time frame to complete the project in stipulated time frame.
  5. After approval from the management, concessionaire shall submit the design to independent consultant for the review and necessary suggestion.
  6. After review, concessionaire will see the feasibility, if found suitable implement the same for the project.
  7. During execution ,from time to time, keep an eye over the design for practical feasibility, if not matching with the site condition , go for the revision & repeat the process mentioned above.

 

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