Summer internship report L&T


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Summer internship report L&T

  1. 1.                       SUMMER  INTERNSHIP  REPORT   (7/5/2012          -­‐        24/6/2012)                                                                                                                                                                                                          Submitted  by:-­‐                                                                                              Umed  Paliwal                Second    Undergraduate  Student,                Department  of  Civil  Engineering,                Indian  Institute  of  Technology  Kanpur                   1  
  2. 2. INDEX    ______________________________________________________________________  Sno.                                                                                  Contents       Page  no.  1         Aknowldgement       3  2         Introduction         4  3         EHS  Department       15  4         QA/QC  Department       21  5         Project  Execution       47  6         Planning           57  7         Conclusion         59  ______________________________________________________________________                                                       2  
  3. 3.   Aknowldgement    I   am   very   thankful   to   LARSEN   &   TOUBRO   CONSTRUCTIONS   BUILDINGS   &  FACTORIES   INDIPENDENT   COMPANY   (L&T   CONSTRUCTION,   B&F   IC)   for  having   given   me   the   opportunity   to   undertake   my   summer   training   at   their  prestigious   FORD   INDIA   PVT   LTD,   #   2   PROJECT.   It   was   a   very   good   learning  experience   for   me   to   have   worked   at   this   site   as   this   project   involved   many  unique  construction  practices  and  challenges.  I  would  like  to  convey  my  heartiest  thanks   to         Mr.   Ashutosh   Tripathi,   L&T   Construction.   Ahmadabad   Cluster  Project  Manager  Factory  Division,  who  heartily  welcomed  me  for  the  internship.  I   would   also   like   to   give   my   heart-­‐felt   thanks   to     Mr.   S.   K.   Basu,   Project   Co-­‐Ordinator,  Mr.   Sudeep   Ghosh   ,QA/QC  Head  who  guided  and  encouraged  me  all  through   the   summer   training   and   imparted   in-­‐depth   knowledge   of   the   project.  Also  I  would  like  to  thank  Mr.  G.  M.  Mir,  Planning  Head,  who  assisted  and  guided  me   whenever   I   needed   help.   I   would   like   to   thank   all   the   department   heads   of  L&T  Construction,  B&F  IC,  for  giving  their  precious  time  and  valuable  guidance  during  my  internship  programme.  Last  but  not  the  least;  I  would  like  to  thank  all  the  staff  at  L&T  Construction  ,  B&F  IC,  for  being  so  helpful  during  this  summer  training.            Name:  Umed  Paliwal  Date:  16th  June  2012     3  
  4. 4. INTRODUCTIONABOUT THE ORGANIZATION:Larsen & Toubro Limited is the biggest legacy of two Danish Engineers, who built aworld-class organization that is professionally managed and a leader in Indiasengineering and construction industry. It was the business of cement that brought theyoung Henning Holck-Larsen and S.K. Toubro into India. They arrived on Indianshores as representatives of the Danish engineering firm F L Smidth & Co inconnection with the merger of cement companies that later grouped into theAssociated Cement Companies.Together, Holck-Larsen and Toubro, founded the partnership firm of L&T in 1938,which was converted into a limited company on February 7, 1946. Today, this hasmetamorphosed into one of Indias biggest success stories. The company has grownfrom humble origins to a large conglomerate spanning engineering and construction.Larsen & Toubro Construction is India’s largest construction organisation. Many ofthe countrys prized landmarks - its exquisite buildings, tallest structures, largestindustrial projects, longest flyover, and highest viaducts - have been built by it.Leading-edge capabilities cover every discipline of construction: civil, mechanical,electrical and instrumentation.L&T Construction has the resources to execute projects of large magnitude andtechnological complexity in any part of the world. The business of L&T Constructionis organized in six business sectors which will primarily be responsible forTechnology Development, Business Development, International Tendering and workas Investment Centres. Head quarters in Chennai, India. In India, 7 Regional Officesand over 250 project sites. In overseas it has offices in Gulf and other overseaslocations.L&T Construction’s cutting edge capabilities cover every discipline of construction –civil, mechanical, electrical and instrumentation engineering and services extend tolarge industrial and infrastructure projects from concept to commissioning.   4  
  5. 5. L&T Construction has played a prominent role in India’s industrial and infrastructuredevelopment by executing several projects across length and breadth of the countryand abroad. For ease of operations and better project management, in-depthtechnology and business development as well as to focus attention on domestic andinternational project execution, entire operation of L&T Construction is structuredinto four Independent Companies. • Hydrocarbon IC • Buildings & Factories IC • Infrastructure IC • Metallurgical & Material Handling IC • Power Transmission & Distribution • Heavy Engineering • Shipbuilding • Power • Electrical & Automation • Machinery & Industrial ProductBUILDING & FACTORIESThe Buildings & Factories Independent Company is equipped with the domainknowledge, requisite expertise and wide-ranging experience to undertakeEngineering, Procurement and Construction (EPC) of all types of building and factorystructures. • Commercial Buildings & Airports • Residential Buildings & FactoriesRESIDENTIAL BUILDINGS & FACTORIESL&T undertakes turnkey construction of a wide range of residential buildings andfactory structures. Projects are executed using the cutting edge technology,sophisticated construction equipment and project management tools for quality, safetyand speed. • Residential Building • Factories   5  
  6. 6. FACTORIESL&T offers design and turnkey construction of heavy and light factories, cement &plants including Defence Projects using the latest construction technology, with afocus on Quality, Safety and Speed. The spectrum covers • Heavy & Light Factories (HLF) –Automobile & Ancillary Factories, Glass plants, Food processing Factories, Pharmaceutical plants, Warehouses & Logistics Parks, Workshop Complexes, Solar thin film manufacturing units, etc. • Cement & Plants (C&P) – Cement Plants, Sugar Plants, Distillery Plants, Food Grain storage structures, Pulp & Paper Mills, Textile Mills etc. • Defence – Construction of Manufacturing Facilities and Warehouse Facilities for Defence.SERVICE SPECTRUML&T Construction’s range of services includes: • Pre-engineering, feasibility studies and detailed project reports. • Complete civil and structural construction services for all types of buildings, industrial and infrastructure projects. • Complete mechanical system engineering including fabrication and erection of structural steel works; manufacture, supply, erection, testing and commissioning of plant and equipment; heavy lift erection; high-pressure piping; fire-fighting; HVAC and LP/ utility piping networks. • Electrical system design, project electrification, automation and control system including instrumentation for all type of industrial and telecom projects. • Design, manufacture, supply and installation of EHV switchyards, transmission lines.   6  
  7. 7. QUALITY POLICYAt L&T, Environment, Health & Safety (EHS) is given the highest priority. The EHSpolicy enunciated by the Corporate Management lays emphasis on Environment,Health and Safety through a structured approach and well defined practices. Systemsand procedures have been established for implementing the requisites at all stages ofconstruction and they are accredited to the International standards of ISO 9001:2008,ISO 14001:2004 and OHSAS 18001:2007.   7  
  9. 9. HR POLICY       9  
  10. 10. WORK CULTURE Work Culture emphasises: • Freedom to experiment • Continuous learning and training • Transparency • Quality in all aspects of work • Rewards based on performance and potentialTRAINING Human Resources Department believes that Quality is the hallmark of any successfulventure. Quality Training and Development of Human Resources is realized through:Identifying training needs within the Organization and designing and implementingthose need based training programs to bring about continuous up-gradation ofknowledge, skills and employee attitudes.VISION & MISSIONVISIONL&T shall be professionally managed Indian multinational committed to totalcustomer satisfaction and enhancing shareholder value. L&T shall be an innovativeentrepreneurial and empowered team constantly creating value and attaining globalbenchmarks. L&T shall foster a culture of caring trust and continuous learning whilemeeting expectations of employees, stakeholders and society.   10  
  11. 11. MISSIONTo achieve excellence in the field of Engineering, Procurement and Constructionthrough world class practice and standards in quality, Safety and ProjectManagement.   11  
  14. 14. BRIEF INTRODUCTION OF PROJECTFord India has laid the foundation for its new US $1 billion state-of-the-art, integratedmanufacturing facility in Sanand and its future growth on the subcontinent. The totalarea of the plant is 406-acre. • Ford India Sanand facility will deploy global best practices and technology including a state-of-the-art Paint Shop • Ford India’s Sanand facility attracts 19 world-class supplier manufacturers to dateFord India is laying the foundation for its new US $1 billion state-of-the-art,integrated manufacturing facility in Sanand and its future growth on the subcontinent.It will be complete in 2014; the integrated manufacturing facility will have thecapacity to produce an additional 240,000 new Ford vehicles and 270,000 engines peryear for Indian customers and for export market.The new state-of-the-art assembly plant will be fully integrated to support stamping,body assembly, paint, trim and final assembly. The paint shop will utilize Ford’senvironmentally friendly rotational dip technology and 3-Wet technology paintprocesses, which will improve paint quality, depth and durability, as well assignificantly reducing Volatile Organic Compounds, CO2 emissions and waste.The idea behind selecting Sanand as project site is, the way the Chennai Port servedthe company’s markets in the East and South East Asia, the Gujarat terminal, or aroll-on roll-off (RoRo) facility, could be used for exports to the western markets likeMexico, South Africa and the Middle East as and when necessary.Plus, the State Government has also prioritized land adjacent to the site for supplieroperations. It will be protected by the local government in order to attract and locateautomotive suppliers within close proximity of both the plants.The project has divided into various packages; L&T has received three packages: firstpackage is Paint shop(Piling work) , second package Engine and third package is TCF.The location of project makes it more important due to TATA NANO PLANT by sideand upcoming MARUTI PLANT.   14  
  15. 15. EHS DEPARTMENT  GENERAL  EHS  RULES  &REGULATIONS     1.  No  workmen  below  18  years  and  above  58  years  of  age  shall  be  engaged  for  a   job.   2.  All  workmen  shall  be  screened  before  engaging  them  on  the  job.  Physical   fitness  of  the  person  to  certain  critical  jobs  like  working  at  height  or  other   dangerous  locations  to  be  ensured  before  engaging  the  person  on  work.  The  final   decision  rests  with  the  site  management  to  reject  any  person  on  the  ground  of   physical  fitness.   3.  Visitors  can  enter  the  site  after  EHS  induction  with  the  visitor  pass.  He  should   be  provided  Safety  helmet  &  safety  Shoes,  also  he  should  be  accompanied  with   the  responsible  person  of  that  area.     4.  Smoking  is  strictly  prohibited  at  workplace.   5.  Sub-­‐contractors  shall  ensure  adequate  supervision  at  workplaces.  They  shall   ensure  that  all  persons  working  under  them  shall  not  create  any  hazard  to  self  or   to  the  co-­‐workers.   6.  Nobody  is  allowed  to  enter  the  site  without  wearing  safety  helmet.  Chinstrap   of  safety  helmet  shall  be  always  on.   7.  No  one  is  allowed  to  work  at  or  more  than  two-­‐meter  height  without  wearing   full  body  harness  and  anchoring  the  lanyard  of  full  body  harness  to  firm  support   preferably  at  shoulder  level.   8.  No  one  is  allowed  to  enter  into  workplace  and  work  at  site  without  adequate   foot  protection  (including  female  worker).   9.  Usage  of  eye  protection  equipment  shall  be  ensured  when  workmen  are   engaged  for  grinding,  chipping,  welding  and  gas  cutting.  For  other  jobs,  as  and   when  site  safety  co-­‐ordinator  insists  eye  protection  has  to  be  provided.   10.  All  PPEs  like  shoes,  helmet,  full  body  harness  etc.  shall  be  arranged  before   starting  the    job  as  per  recommendation  of  the  EHSO.   11.  Rigid  barrication  must  be  provided  around  the  excavated  pits,  and   barrication  shall  be  maintained  till  the  backfilling  is  done.  Safe  approach  is  to  be   ensured  into  every  excavation.     15  
  16. 16. 12.  Adequate  illumination  at  workplace  shall  be  ensured  before  starting  the  job   at  night.   13.  All  the  dangerous  moving  parts  of  the  portable/fixed  machinery  being  used   shall  be  adequately  guarded.   14.  Ladders  being  used  at  site  shall  be  adequately  secured  at  bottom  and  top.   Ladder  shall  not  be  used  as  work  platforms.   15.  Erection  zone  and  dismantling  zone  shall  be  barricaded  and  nobody  will  be   allowed  to  stand  under  the  suspended  loads.     16.  Horseplay  is  completely  prohibited  at  workplace.  Running  at  site  is   completely  prohibited  except  in  case  of  emergency.   17.  Material  shall  not  be  thrown  from  the  height.  Proper  arrangement  of  Debris   Chute  can  be  installed.   18.  Other  than  the  electrician  possessing  B  licence  with  red  helmet,  no  one  is   allowed  to  carryout  electrical  connection,  repairs  on  electrical  equipment  or   other  job  related  thereto.     19.  Inserting  of  bare  wires  for  tapping  the  power  from  electrical  socket  is   completely  prohibited.   20.  All  major,  minor  accidents  near  misses  and  unhygienic  conditions  must  be   reported.   21.  All  scaffoldings/  work  platform  shall  meet  the  requirement.  The  width  of  the   working  platform  and  fall  protection  arrangement  shall  be  maintained  as  per  the   Standard.  All  tools  and  tackles  shall  be  inspected  before  use.  Defects  to  be   reported  immediately.  No  lifting  tool&tackle  to  be  used  unless  it  is  certified  by   the  concerned  Engineer  Incharge  /  P&M  engineer.   22.  Good  house  keeping  to  be  maintained.  Passage  shall  not  be  blocked  with   materials.  Material  like  bricks  shall  not  be  stacked  to  the  dangerous  height  at   workplace.   23.  Debris,  scrap  and  other  material  to  be  cleared  then  and  there  from  the  work   place  and  at  the  time  of  closing  of  work  every  day.   24.  Contractors  shall  ensure  that  all  their  workmen  are  following  safe  practices   while  travelling  in  the  company’s  transport  and  staying  at  company’s   accommodations.     25.  Adequate  fire  fighting  equipment  shall  be  made  available  a  workplace  and   persons  to  be  trained  in  fire  fighting  techniques  with  the  co-­‐ordination  of  EHSO.   26.  All  the  unsafe  conditions,  unsafe  act  identified  by  the  contractors,  reported   by  site  supervisor  and  /  or  safety  personnel  to  be  corrected  on  priority  basis.     16  
  17. 17. 27.  No  children  shall  be  allowed  to  enter  the  workplace.   28.  Workwomen  are  not  allowed  to  work  at  high-­‐risk  areas.     29.  Other  than  the  Driver/operator,  no  one  shall  travel  in  a  tractor  /  tough  rider   etc.       30.  Wherever  the  vehicle/equipment  has  to  work  near  or  pass  through  the   overhead  electrical  lines,  the  goal  post  shall  be  installed.       31.  Identity  card  should  always  be  displayed  and  shown  when  demanded.   32.  Any  person  found  to  be  interfering  with  or  misusing  fixtures,  fittings  or   equipment  provided  in  the  interest  of  health,  safety  and  welfare  would  be   excluded  from  site.(  like  using  helmet  and  fire  bucket  for  carrying  the  material,   removing  the  handrails,  etc.)   33.  Visitors  must  use  safety  helmet  before  entering  the  Site.     34.  Safety  signs  and  notices  must  be  displayed  and  followed.   35.  Transistor  radios  or  personal  stereos  /  Walkman  must  not  be  used.   36.  All  site  personnel,  for  their  own  safety  and  for  the  safety  of  others,  are   required  to  fully  comply  with  the  agreed  safety  systems/  procedures  and   working  method.   37.  Consumption  of  alcohol  and  drugs  is  prohibited.   38.  No  person  is  to  operate  any  mechanical  /  Electrical  equipment  unless  they   have  been  authorized  and  have  been  certified  as  competent.   39.  Take  Food  only  at  the  designated  area  (like  dinning,  Rest  Room  etc).    The   Waste  food,  PVC/Paper  covers  need  to  be  dumped  in  the  Dustbin.  The  House   keeping  gang  on  regular  intervals  will  clear  this.  Also  hand  /  vessels  should  be   washed  in  the  same  area  with  proper  drainage.   40.  No  workers  should  enter  the  site  with  lunghies  and  dhotis.   41.  No  body  should  sit    /  sleep  on  the    floor  edges.   42.  Don’t  enter  inside  the  room  where  there  is  no  light.   43.  Don’t  take  shelter  under  the  vehicle  or  in  an  electrical  installation  rooms.   44.  Look  for  warnings  signs,  caution  boards  and  other  notices.   45.  Must  be  aware  about  the  locations  of  the  first  aid  canter,  fire  extinguisher,   emergency  assembly  point  and  emergency  siren.   46.  No  floor  opening,  floor  edges  should  be  left  unguarded   47.  Training  is  must  for  all  scaffolders  and  only  trained  scaffolders  should  make   platforms.   48.  Don’t  keep  loose  materials  at  height.   49.  Permission  should  be  taken  for  all  earthworks  from  P&M  Department.     17  
  18. 18. 50.  Those  who  are  violating  the  safety  norms  will  be  penalized.     51.  Female  workers  should  not  be  engaged  on  work  between  7.P.M.    To  8  A.M.   52.  Physical  fitness  check  shall  be  carried  out  for  crane  operators  &  Drivers.                    53.  PPE  Shall  is  provided  to  visitors  at  gate.   54.  No  smoking  sign  boards  shall  be  kept  at  flammable  and  combustible  material                                                                                  Storage  places.                                  55.  Debris,  scrap  and  other  materials  shall  be  disposed  daily  at  closing  hours  of                                        the  day  by  the  same  crew.                        56.  Environment  poster  shall  be  displayed  at  site  as  and  when  required                                    Depending  upon  the  activities  in  progress.                          57.  Fire  points  should  be  placed  at  all  required  areas                                                                                             Use of Personal Protective Equipment and safety devices relevant to site activities. • SAFETY APPLIANCES The  requirement  of  sufficient  number  of  safety  appliances  are  planned  well  in   advance  and  made  available  at  stores.   • HEAD PROTECTION Every  individual  entering  the  site  must  wear  safety  helmet,  confirming  to  IS:   2925-­‐  1984  with  the    chinstrap  fixed  to  the  chin.   • FOOT AND LEG PROTECTION  Safety  footwear  with  steel  toe  is  essential  on  site  to  prevent  crush  injuries  to   our  toes  and  injury  due  to  striking  against  the  object.   • HEARING PROTECTION: Excessive  noise  causes  damage  to  the  inner  ear  and  permanent  loss  of  hearing.   To  protect  ears  use  ear  plugs  /  ear  muff  as  suitable     18  
  19. 19. • EYE PROTECTION Person  carrying  out  grinding  works,  operating  pavement  breakers,  and  those   involved  in  welding  and  cutting  works  should  wear  safety  goggles  &  face  shield   suitably.  Goggles,  Safety  Spectacles,  face  shield  confirm  to  IS:  5983-­‐1980.   • EAR PROTECTION Ear Muff / Earplug should be provided to those working at places with high sound levels (confirm to IS: 9167-1979). • HAND AND ARM PROTECTION: While handling cement and concrete & while carrying out hot works like gas cutting, grinding & welding usage of hand gloves is a must to protect the hand, 1)  COTTON  Gloves  (for  materials  handling)-­‐IS:  6994-­‐1973   2)   RUBEER  Gloves-­‐18”  (380/450mm  long)  electrical  grade,  tested   to  15000  Volts  conforming  to  IS:  4770-­‐1991   3)  LEATHER  Gloves  –  hot  work  /  handling  of  sharp  edges   • RESPIRATORY PROTECTION Required  respiratory  protection  according  to  the  exposure  of  hazards  to   be  provided.   • SAFETY NET Though  it  is  mandatory  to  wear  safety  harness  while  working  at  height   on   the   working   platforms,   safety   nets   of   suitable   mesh   size   shall   be   provided  to  arrest  the  falling  of  person  and  materials  on  need  basis.   • FALL PROTECTION: To   prevent   fall   of   person   while   working   at   height,   personnel   engaged   more  than  2m  wear  standard  Full  Body  harness  should  be  conforming   to  IS:  3521-­‐1999(Third  Revision).       19  
  20. 20. 1) Lanyard  should  be  of  12mm  Polypropylene  rope  and  of  length  not   more  than  2m.   2) Double  lanyard,  based  on  the  requirement.           20  
  21. 21. QUALITY ASSURANCE & QUALITY CONTROL DEPARTMENT  Quality is the key component which propels performance and defines leadershiptraits. At L&T Construction, Quality Standards have been internalised anddocumented in Quality Assurance manuals. L&T Construction recognizes the crucialsignificance of the human element in ensuring quality. Structured trainingprogrammes ensure that every L&T employee is conscious of his/her role andresponsibility in extending L&T Construction’s tradition of leadership throughquality. A commitment to safety springs from a concern for the individual worker –every one of the thousands braving the rigours of construction at numerous projectsites. L&T, Buildings & Factories IC has a well-established and documented QualityManagement System (QMS) and is taking appropriate steps to improve itseffectiveness in accordance with the requirements of ISO 9001:2008. Relevantprocedures established clearly specify the criteria and methods for effective operation,control and necessary resources and information to support the operation andmonitoring of these processes.QUALITY IMPLEMENTATION AT SITEL&T, Buildings & Factories IC has established procedure for monitoring, measuringand analyzing of these processes and to take necessary actions to achieve plannedresults and continual improvement of these processes. It has also maintained relevantprocedures to identify and exercise required control over outsourced processes, if any.Systems and procedures have been established for implementing the requisites at allstages of construction and they are accredited to the International standards of ISO9001:2008, ISO 14001:2004 and OHSAS 18001:2007. L&T continues to maintain thetrail blazing tradition of meeting the stringent quality standards and adherence to timeschedules in all the projects.PROJECT QUALITY PLAN (PQP):The Project Quality Plan is prepared and formulated as a Management Summary ofQuality related activities required to meet the terms of contract. This Quality plan setsout the Management practices and describes the Quality Management System based   21  
  22. 22. on PDCA (Plan, Check, Do and Act) Principle. The Project Quality Plan comprises oftwo sections: A. VOLUME ISCOPE: The contents of this document are applicable to “SHOP CONSTRUCTION FOR M/s. FORD INDIA Pvt. Ltd.” and “Construction of Civil and Structural works for M/s. FORD INDIA Pvt. Ltd. At Sanand, Gujarat” that will be carried out by Larsen & Toubro Limited, Buildings & Factories IC for FIPL. In preparation of this document, due regard has been paid to the requirements of ISO 9001: 2008 series of System Standards.PURPOSE: This Project Quality Plan is prepared and formulated as a Management Summary of Quality related activities required to meet the terms of contract. This Quality plan sets out the Management practices and describes the Quality Management System.   TESTS ON CEMENT CONSISTENCYAIMTo determine the quantity of water required to produce a cement paste of standardconsistency as per IS: 4031 (Part 4) - 1988.PRINCIPLEThe standard consistency of a cement paste is defined as that consistency which willpermit the Vicat plunger to penetrate to a point 5 to 7mm from the bottom of the Vicatmould.APPARATUS   22  
  23. 23. VICAT APPARATUSVicat apparatus conforming to IS: 5513 - 1976 Balance, whose permissible variationat a load of 1000g should be +1.0g Gauging trowel conforming to IS: 10086 - 1982PROCEDUREi) Weigh approximately 400g of cement and mix it with a weighed quantity of water.The time of gauging should be between 3 to 5 minutes.ii) Fill the Vicat mould with paste and level it with a trowel. iii) Lower the plungergently till it touches the cement surface.iv) Release the plunger allowing it to sink into the paste.v) Note the reading on the Repeat the above procedure taking fresh samples of cement and differentquantities of water until the reading on the gauge is 5 to 7mm.REPORTING OF RESULTSExpress the amount of water as a percentage of the weight of dry cement to the firstplace of decimal. INITIAL AND FINAL SETTING TIMEAIMTo determine the initial and the final setting time of cement as per IS: 4031 (Part 5) -1988.APPARATUSVicat apparatus conforming to IS: 5513 - 1976 Balance, whose permissible variationat a load of 1000g should be +1.0g Gauging trowel conforming to IS: 10086 - 1982PROCEDUREi) Prepare a cement paste by gauging the cement with 0.85 times the water required togive a paste of standard consistency   23  
  24. 24. ii) Start a stop-watch, the moment water is added to the cement.iii) Fill the Vicat mould completely with the cement paste gauged as above, the mouldresting on a non-porous plate and smooth off the surface of the paste making it levelwith the top of the mould. The cement block thus prepared in the mould is the testblock. INITIAL SETTING TIMEPlace the test block under the rod bearing the needle. Lower the needle gently in orderto make contact with the surface of the cement paste and release quickly, allowing itto penetrate the test block. Repeat the procedure till the needle fails to pierce the testblock to a point 5.0 ± 0.5mm measured from the bottom of the mould . The timeperiod elapsing between the time, water is added to the cement and the time, theneedle fails to pierce the test block by 5.0 ± 0.5mm measured from the bottom of themould, is the initial setting time. FINAL SETTING TIMEReplace the above needle by the one with an annular attachment.The cement should be considered as finally set when, upon applying the needle gentlyto the surface of the test block, the needle makes an impression therein, while theattachment fails to do so. The period elapsing between the time, water is added to thecement and the time, the needle makes an impression on the surface of the test block,while the attachment fails to do so, is the final setting time.REPORTING OF RESULTSThe results of the initial and the final setting time should be reported to the nearestfive minutes.   24  
  25. 25. TESTS ON AGGREGATES SIEVE ANALYSISAIMTo determine the particle size distribution of fine and coarse aggregates by sieving asper IS: 2386 (Part I) - 1963.PRINCIPLEBy passing the sample downward through a series of standard sieves, each ofdecreasing size openings, the aggregates are separated into several groups, each ofwhich contains aggregates in a particular size range.APPARATUSA SET OF IS SIEVESi) A set of IS Sieves of sizes - 80mm, 63mm, 50mm, 40mm, 31.5mm, 25mm, 20mm,16mm, 12.5mm, 10mm, 6.3mm, 4.75mm, 3.35mm, 2.36mm, 1.18mm, 600µm,300µm, 150µm and 75µmii)Balance or scale with an accuracy to measure 0.1 percent of the weight of the testsamplePROCEDUREi) The test sample is dried to a constant weight at a temperature of 110 + 5oC andweighed.ii) The sample is sieved by using a set of IS Sieves.iii) On completion of sieving, the material on each sieve is weighed.iv) Cumulative weight passing through each sieve is calculated as a percentage of thetotal sample weight.v) Fineness modulus is obtained by adding cumulative percentage of aggregatesretained on each sieve and dividing the sum by 100.   25  
  26. 26. REPORTING OF RESULTSThe results should be calculated and reported as:i) the cumulative percentage by weight of the total sampleii) the percentage by weight of the total sample passing through one sieve andretained on the next smaller sieve, to the nearest 0.1 percent. WATER ABSORPTIONAIMTo determine the water absorption of coarse aggregates as per IS: 2386 (Part III) -1963.APPARATUSi) Wire basket - perforated, electroplated or plastic coated with wire hangers forsuspending it from the balanceii) Water-tight container for suspending the basketiii)Dry soft absorbent cloth - 75cm x 45cm (2 nos.)iv) Shallow tray of minimum 650 areav) Air-tight container of a capacity similar to the basketvi) Oven SAMPLE A sample not less than 2000g should be used.PROCEDUREi) The sample should be thoroughly washed to remove finer particles and dust,drained and then placed in the wire basket and immersed in distilled water at atemperature between 22 and 32oC.ii) After immersion, the entrapped air should be removed by lifting the basket andallowing it to drop 25 times in 25 seconds. The basket and sample should remainimmersed for a period of 24 + 1⁄2 hrs. afterwards.   26  
  27. 27. iii) The basket and aggregates should then be removed from the water, allowed todrain for a few minutes, after which the aggregates should be gently emptied from thebasket on to one of the dry clothes and gently surface-dried with the cloth,transferring it to a second dry cloth when the first would remove no further moisture.The aggregates should be spread on the second cloth and exposed to the atmosphereaway from direct sunlight till it appears to be completely surface-dry. The aggregatesshould be weighed (Weight A).iv) The aggregates should then be placed in an oven at a temperature of 100 to 110oCfor 24hrs. It should then be removed from the oven, cooled and weighed (Weight B).REPORTING OF RESULTSWater absorption = [(A-B)/B] x 100% TESTS ON FRESH CONCRETE SLUMPAIMTo determine the workability of fresh concrete by slump test as per IS: 1199 - 1959.APPARATUSi) Slump coneii) Tamping rodPROCEDUREi) The internal surface of the mould is thoroughly cleaned and applied with a lightcoat of oil.ii) The mould is placed on a smooth, horizontal, rigid and non- absorbent surface.iii) The mould is then filled in four layers with freshly mixed concrete, eachapproximately to one-fourth of the height of the mould.   27  
  28. 28. iv) Each layer is tamped 25 times by the rounded end of the tamping rod (strokes aredistributed evenly over the cross- section).v) After the top layer is rodded, the concrete is struck off the level with a The mould is removed from the concrete immediately by raising it slowly in thevertical direction.vii)The difference in level between the height of the mould and that of the highestpoint of the subsided concrete is measured.viii) This difference in height in mm is the slump of the concrete.REPORTING OF RESULTSThe slump measured should be recorded in mm of subsidence of the specimen duringthe test. Any slump specimen, which collapses or shears off laterally gives incorrectresult and if this occurs, the test should be repeated with another sample. If, in therepeat test also, the specimen shears, the slump should be measured and the fact thatthe specimen sheared, should be recorded. OMC & MDD TESTThis test is done to determine the maximum dry density and the optimum moisturecontent of soil using heavy compaction as per IS: 2720 (Part 8 ) – 1983.The apparatusused is:-i) Cylindrical metal mould – it should be either of 100mm dia. and 1000cc volume or150mm dia. and 2250cc volume and should conform to IS: 10074 – 1982.ii) Balances – one of 10kg capacity, sensitive to 1g and the other of 200g capacity,sensitive to 0.01giii) Oven – thermostatically controlled with an interior of noncorroding material tomaintain temperature between 105 and 110oCiv) Steel straightedge – 30cm longv) IS Sieves of sizes – 4.75mm, 19mm and 37.5mm   28  
  29. 29. PREPARATION OF SAMPLEA representative portion of air-dried soil material, large enough to provide about 6kgof material passing through a 19mm IS Sieve (for soils not susceptible to crushingduring compaction) or about 15kg of material passing through a 19mm IS Sieve (forsoils susceptible to crushing during compaction), should be taken. This portion shouldbe sieved through a 19mm IS Sieve and the coarse fraction rejected after itsproportion of the total sample has been recorded. Aggregations of particles should bebroken down so that if the sample was sieved through a 4.75mm IS Sieve, onlyseparated individual particles would be retained.Procedure To Determine The Maximum Dry Density And The OptimumMoisture Content Of SoilA) Soil not susceptible to crushing during compaction –i) A 5kg sample of air-dried soil passing through the 19mm IS Sieve should be taken.The sample should be mixed thoroughly with a suitable amount of water dependingon the soil type (for sandy and gravelly soil – 3 to 5% and for cohesive soil – 12 to16% below the plastic limit). The soil sample should be stored in a sealed containerfor a minimum period of 16hrs.ii) The mould of 1000cc capacity with base plate attached, should be weighed to thenearest 1g (W1 ). The mould should be placed on a solid base, such as a concrete flooror plinth and the moist soil should be compacted into the mould, with the extensionattached, in five layers of approximately equal mass, each layer being given 25 blowsfrom the 4.9kg rammer dropped from a height of 450mm above the soil. The blowsshould be distributed uniformly over the surface of each layer. The amount of soilused should be sufficient to fill the mould, leaving not more than about 6mm to bestruck off when the extension is removed. The extension should be removed and thecompacted soil should be levelled off carefully to the top of the mould by means ofthe straight edge. The mould and soil should then be weighed to the nearest gram(W2).iii) The compacted soil specimen should be removed from the mould and placed ontothe mixing tray. The water content (w) of a representative sample of the specimenshould be determined.   29  
  30. 30. iv) The remaining soil specimen should be broken up, rubbed through 19mm IS Sieveand then mixed with the remaining original sample. Suitable increments of watershould be added successively and mixed into the sample, and the above operations i.e.ii) to iv) should be repeated for each increment of water added. The total number ofdeterminations made should be at least five and the moisture contents should be suchthat the optimum moisture content at which the maximum dry density occurs,lies within that range.B) Soil susceptible to crushing during compaction –Five or more 2.5kg samples of air-dried soil passing through the 19mm IS Sieve,should be taken. The samples should each be mixed thoroughly with differentamounts of water and stored in a sealed container as mentioned in Part A)C) Compaction in large size mould –For compacting soil containing coarse material upto 37.5mm size, the 2250cc mouldshould be used. A sample weighing about 30kg and passing through the 37.5mm ISSieve is used for the test. Soil is compacted in five layers, each layer being given 55blows of the 4.9kg rammer. The rest of the procedure is same as above.REPORTING OF RESULTSBulk density Y(gamma) in g/cc of each compacted specimen should becalculated from the equation,Y(gamma) = (W2-W1)/ Vwhere, V = volume in cc of the mould.The dry density Yd in g/ccYd = 100Y/(100+w)The dry densities, Yd obtained in a series of determinations should be plotted againstthe corresponding moisture contents,w. A smooth curve should be drawn through theresulting points and the position of the maximum on the curve should be determinedThe dry density in g/cc corresponding to the maximum point on the moisturecontent/dry density curve should be reported as the maximum dry density to thenearest 0.01. The percentage moisture content corresponding to the maximum drydensity on the moisture content/dry density curve should be reported as the optimum   30  
  31. 31. moisture content and quoted to the nearest 0.2 for values below 5 percent, to thenearest 0.5 for values from 5 to 10 percent and to the nearest whole number for valuesexceeding 10 percent. WATER CONTENT OVEN DRYING METHODAIMTo determine the water content in soil by oven drying method as per IS: 2720 (Part II)- 1973.PRINCIPLEThe water content (w) of a soil sample is equal to the mass of water divided by themass of solids.APPARATUSi) Thermostatically controlled oven maintained at a temperature of 110 ± 5oCii) Weighing balance, with an accuracy of 0.04% of the weight of the soil takeniii) Air-tight container made of non-corrodible material with lidiv) TongsSAMPLEThe soil specimen should be representative of the soil mass. The quantity of thespecimen taken would depend upon the gradation and the maximum size of particlesas under:PROCEDUREi) Clean the container, dry it and weigh it with the lid (Weight W1).ii) Take the required quantity of the wet soil specimen in the container and weigh itwith the lid (Weight W2).iii) Place the container, with its lid removed, in the oven till its weight becomesconstant (Normally for 24hrs.).iv) When the soil has dried, remove the container from the oven, using tongs.v) Find the weight W3 of the container with the lid and the dry soil sample.   31  
  32. 32. REPORTING OF RESULTSThe water content w = [(W2 − W3) ×100%] /(W3 −W1) CALCIUM CARBIDE METHOD(RAPID MOISTURE METER TEST)AIMTo determine the water content in soil by calcium carbide method as per IS: 2720(Part II) - 1973.PRINCIPLEIt is a method for rapid determination of water content from the gas pressuredeveloped by the reaction of calcium carbide with the free water of the soil. From thecalibrated scale of the pressure gauge the percentage of water on total mass of wet soilis obtained and the same is converted to water content on dry mass of soil.APPARATUSi) Metallic pressure vessel, with a clamp for sealing the cup, alongwith a gaugecalibrated in percentage water contentii) Counterpoised balance, for weighing the sampleiii) Scoop, for measuring the absorbent (Calcium Carbide)iv) Steel balls - 3 steel balls of about 12.5mm dia. and 1 steel ball of 25mm dia.v) One bottle of the absorbent (Calcium Carbide)PREPARATION OF SAMPLESand - No special preparation. Coarse powders may be ground and pulverized.Cohesive and plastic soil - Soil is tested with addition of steel ball in the pressurevessels.The test requires about 6g of sample.PROCEDUREi) Set up the balance, place the sample in the pan till the mark on the balance armmatches with the index mark.ii) Check that the cup and the body are clean.iii) Hold the body horizontally and gently deposit the levelled, scoop-full of the   32  
  33. 33. absorbent (Calcium Carbide) inside the chamber.iv) Transfer the weighed soil from the pan to the cup.v) Hold cup and chamber horizontally, bringing them together without disturbing thesample and the Clamp the cup tightly into place. If the sample is bulky, reverse the aboveplacement, that is, put the sample in the chamber and the absorbent in the cup.vii) In case of clayey soils, place all the 4 steel balls (3 smaller and 1 bigger) in thebody alongwith the absorbent.viii) Shake the unit up and down vigorously in this position for about 15 seconds.ix) Hold the unit horizontally, rotating it for 10 seconds, so that the balls roll aroundthe inner circumference of the body.x) Rest for 20 seconds.xi) Repeat the above cycle until the pressure gauge reading is constant and note thereading. Usually it takes 4 to 8 minutes to achieve constant reading. This is the watercontent (m) obtained on wet mass basis.xii) Finally, release the pressure slowly by opening the clamp screw and taking thecup out, empty the contents and clean the instrument with a brush.REPORTING OF RESULTSThe water content on dry mass basis,W = (m/100 – m)*100% IN-SITU DRY DENSITY CORE CUTTER METHODAIMTo determine the in-situ dry density of soil by core cutter method as per IS: 2720 (PartXXIX) - 1975.APPARATUSi) Cylindrical core cutterii) Steel dolleyiii) Steel rammer   33  
  34. 34. iv) Balance, with an accuracy of 1gv) Straightedgevi) Square metal tray - 300mm x 300mm x 40mmvii) TrowelPROCEDUREi) The internal volume (V) of the core cutter in cc should be calculated from itsdimensions which should be measured to the nearest 0.25mm.ii) The core cutter should be weighed to the nearest gram (W1).iii) A small area, approximately 30cm square of the soil layer to be tested should beexposed and levelled. The steel dolly should be placed on top of the cutter and thelatter should be rammed down vertically into the soil layer until only about 15mm ofthe dolly protrudes above the surface, care being taken not to rock the cutter. Thecutter should then be dug out of the surrounding soil, care being taken to allow somesoil to project from the lower end of the cutter. The ends of the soil core should thenbe trimmed flat in level with the ends of the cutter by means of the straightedge.iv) The cutter containing the soil core should be weighed to the nearest gram (W2).v) The soil core should be removed from the cutter and a representative sample shouldbe placed in an air-tight container and its water content (w) determined as in Para 5.1.REPORTING OF RESULTSBulk density of the soil γ = (W2 −W1)/V g /ccDry density of the soil γd = [100γ/100+w] g cc MIX DESIGNConcrete is the basic engineering material used in most of the civil engineeringstructures. Its popularity as basic building material in construction is because of, itseconomy of use, good durability and ease with which it can be manufactured at site.The ability to mould it into any shape and size, because of its plasticity in green stageand its subsequent hardening to achieve strength, is particularly useful.Concrete like other engineering materials needs to be designed for properties likestrength, durability, workability and cohesion. Concrete mix design is the science ofdeciding relative proportions of ingredients of concrete, to achieve the desired   34  
  35. 35. properties in the most economical way.With advent of high-rise buildings and pre-stressed concrete, use of higher grades ofconcrete is becoming more common. Even the revised IS 456-2000 advocates use ofhigher grade of concrete for more severe conditions of exposure, for durabilityconsiderations. With advent of new generation admixtures, it is possible to achievehigher grades of concrete with high workability levels economically. Use of mineraladmixtures like fly ash, slag, meta kaolin and silica fume have revolutionised theconcrete technology by increasing strength and durability of concrete by many folds.Mix design of concrete is becoming more relevant in the above-mentioned scenario.However, it should be borne in mind that mix design when adopted at site shouldbe implemented with proper understanding and with necessary precautions.Durocrete mix design manual is an attempt to increase the awareness among theusers, about concrete mix design. It is made with intention of serving as readyreckoner for personnel, implementing mix design at site.Advantages of mix designMix design aims to achieve good quality concrete at site economically.I. Quality concrete means Better strength Better imperviousness and durability Denseand homogeneous concreteII. Economya) Economy in cement consumptionIt is possible to save up to 15% of cement for M20 grade of concrete with the help ofconcrete mix design. In fact higher the grade of concrete more are the savings. Lowercement content also results in lower heat of hydration and hence reduces shrinkagecracks.b) Best use of available materials:Site conditions often restrict the quality and quantity of ingredient materials. Concretemix design offers a lot of flexibility on type of aggregates to be used in mix design.Mix design can give an economical solution based on the available materials if theymeet the basic IS requirements. This can lead to saving in transportation costs fromlonger distances.c) Other properties:Mix design can help us to achieve form finishes, high early strengths for earlydeshuttering, concrete with better flexural strengths, concrete with pumpability and   35  
  36. 36. concrete with lower densities.What is mix design?Concrete is an extremely versatile building material because, it can be designed forstrength ranging from M10 (10Mpa) to M100 (100 Mpa) and workability rangingfrom 0 mm slump to 150 mm slump. In all these cases the basic ingredients ofconcrete are the same, but it is their relative proportioning that makes thedifference.Basic Ingredients of Concrete: -1. Cement – It is the basic binding material in concrete. 2. Water – It hydrates cement and also makes concrete workable.3. Coarse Aggregate – It is the basic building component of concrete.4. Fine Aggregate – Along with cement paste it forms mortar grout and fills the voidsin the coarse aggregates.5. Admixtures – They enhance certain properties of concrete e.g. gain of strength,workability, setting properties, imperviousness etcConcrete needs to be designed for certain properties in the plastic stage as well as inthe hardened stage.Properties desired from concrete in plastic stage: -Workability Cohesiveness Initial set retardationProperties desired from concrete in hardened stage: -Strength Imperviousness DurabilityConcrete mix design is the method of correct proportioning of ingredients ofconcrete, in order to optimise the above properties of concrete as per siterequirements.In other words, we determine the relative proportions of ingredients of concreteto achieve desired strength & workability in a most economical way.Information required for concrete mix designThe site engineer should give following information while giving material for mix   36  
  37. 37. design to the mix design laboratory: -Grade of concrete (the characteristic strength)Workability requirement in terms of slumpOther properties (if required): -i. Retardation of initial set (to avoid cold joints in case of longer leads or for readymix concrete) ii. Slump retention (in case of ready mix concrete) iii. Pumpability (In case of ready mix concrete)iv.Acceleration of strength (for precast members or where early deshuttering isdesired) v. Flexural strength (normally required for concrete pavements)Ascertain whether condition of exposure to concrete is mild, moderate severe or verysevere. Proper investigation of soil should be done to ascertain presence of sulphates& chlorides, in case of doubt.Following factors indicate degree of control at site: -Batching – weigh batching / volume batching.Type of aggregates – whether mixed graded aggregate will be used or 20mm, 10mmaggregates will be used separately.Testing of concrete – whether casting & testing of concrete cubes will be doneregularly at site.Source of aggregate – whether sources of sand and aggregate will be standardised orlikely to change frequently.Supervision – whether qualified staff will be present to supervise concreting work andmake necessary corrections e.g. correction for moisture in sand and changes inmaterial properties.Site laboratory – whether the site will have necessary laboratory equipment likesieves, weighing balance etc. to check material properties.Material properties and how they affect mix design Cementa) Strength/grade of cement: Grade of cement e.g. 43 grade or 53 grade caninfluence the mix design. Grade of cement indicates minimum strength of cement inN/mm2 tested as per standard conditions laid down by IS codes (OPC 43 grade – IS8112-1989, OPC 53 grade – IS 12269 – 1987 e.g. a 43 grade cement should giveminimum strength of 43 N/mm2 at 28 days). Higher the strength of cement, higher is   37  
  38. 38. the strength of concrete for the same water/cement ratio. In other words a higherstrength of cement permits use of higher water/cement ratio to achieve the samestrength of concrete. The IS 10262 - 1982 for mix design gives the different curves ofcement based on the actual strength of cement on 28th day. These cement curves givewater/cement ratio required to achieve a given target strength. Information on gradeof cement may not be as useful as the actual 28days strength of cement. This isbecause some of the 43 grade cements practically give strengths more than 53N/mm2. When a 53-grade cement is stored for a long time, its strength maydeteriorate and become equivalent to 33 grade or 43 grade cement. Thus 28 daysstrength of cement is required to select the cement curve before starting the mixdesign. Finding the 28 days strengths of cement consumes time. It is not practical inmany cases to wait for 28 days strength of cement to start the mix design. In suchcases 28 days strength reports of the manufacturers may be used and can besupplemented by accelerated strength of cement found by reference mix methodgiven in IS 10262 Apart from strength of cement, the type of cement e.g. OrdinaryPortland Cement, pozzolona cement (blended cement) etc, is also important factoraffecting the gain of strength. Blended cements achieve strengths later than OrdinaryPortland Cements and require extended curing period. However, use of these cementsresult in more durable concrete by offering greater resistance to sulphate and chlorideattacks.b) Initial & Final setting time of cement: The initial setting time of cement indicatesthe time after which the cement paste looses its plasticity. Operations like mixing,placing and compaction should be completed well before the initial setting time ofcement .The minimum initial setting time specified by IS 456 –2000 (Clause no 14 and IS 8112-1989 page 2) is 30 minute. Most of the cements producedtoday give an initial set of more than 60 minutes. Beginning of hardening of cementpaste indicates the final setting of cement. The maximum limit for final settingpermitted by IS 8112: 1989 (Clause 6.3. page 2) is 600 minute. Most of the cementsproduced today give a final setting of between 3 to 5 hours. Curing can be startedafter final setting of cement. The initial setting and the final setting can be extendedby use of retarders in order to avoid cold joints when lead-time for placing concrete islonger.Fine Aggregates a) Gradation of fine aggregates: The gradation of sand is given by sieve analysis.   38  
  39. 39. The sieve analysis is done by passing sand through a set of standard sieves andfinding out cumulative passing percentage through each sieve. The IS 383 – 1970classifies fine aggregates in 4 zones starting from zone I representing coarse sand, tozone IV representing the finest sand. The limits of cumulative percentage passing foreach sieve for above zones are given in table 4 of IS 383 The fineness of sand foundby sieve analysis governs the proportion of sand in concrete .The overall fineness ofsand is given by factor called fineness modulus. Fineness Modulus is given bydivision of the summation of cumulative retained fractions for standard sieves up to150-micron sieve size by 100.c) Silt Content by weight: This is found by wet-sieving of sand and material passing75 micron sieve is classified as silt. This silt affects the workability of concrete,results in higher water/cement ratio and lower strength. The upper limit for 75-micronsieve in case of sand is 3% by weight. This limit has however been extended to 15%in case of crushed sand in IS 383 – 1970 Table 1Coarse Aggregatea) Maximum size of coarse aggregate: Maximum size of aggregate is the standardsieve size (40mm, 25mm, 20mm, 12.5mm, 10mm) through which at least 90% ofcoarse aggregate will pass. Maximum size of aggregate affects the workability andstrength of concrete. It alsoinfluences the water demand for getting a certain workability and fine aggregatecontent required for achieving a cohesive mix. For a given weight, higher themaximum size of aggregate, lower is the surface area of coarse aggregates and viceversa. As maximum size of coarse aggregate reduces, surface area of coarse aggregateincreases. Higher the surface area, greater is the water demand to coat the particlesand generate workability. Smaller maximum size of coarse aggregate will requiregreater fine aggregate content to coat particles and maintain cohesiveness of concretemix. Hence 40 mm down coarse aggregate will require much less water than 20 mmdown aggregate. In other words for the same workability, 40mm down aggregate willhave lower water/cement ratio, thus higher strength when compared to 20mm downaggregate. Because of its lower water demand, advantage of higher maximum size ofcoarse aggregate can be taken to lower the cement consumption. Maximum size ofaggregate is often restricted by clear cover and minimum distance between the   39  
  40. 40. reinforcement bars. Maximum size of coarse aggregate should be 5 mm less than clearcover or minimum distance between the reinforcement bars, so that the aggregates canpass through the reinforcement in congested areas, to produce dense and homogenousconcrete.It is advantageous to use greater maximum size of coarse aggregate for concretegrades up to M 35 where mortar failure is predominant. Lower water/cement ratio willmean higher strength of mortar (which is the weakest link) and will result in higherstrength of concrete. However, for concrete grades above M40, bond failure becomespredominant. Higher maximum size of aggregate, which will have lower area ofcontact with cement mortar paste, will fail earlier because of bond failure. Hence forhigher grades of concrete (M40 and higher) it is advantageous to use lower maximumsize of aggregate to prevent bond failure.The fineness modulus of sand varies from 2.0 to 4.0; higher the FM coarser is thesand.Type of SandFine Medium Coarse- FM- 2.0 to 2.8 - 2.8 to 3.2 - 3.2 and aboveb) Specific gravity of fine aggregates: This is the ratio of solid density particles tothe density of water. Higher the specific gravity, heavier is the sand particles andhigher is the density of concrete. Conversely a lower specific gravity of sand willresult in lower density of concrete. Specific gravity of sand is found with help ofpycnometer bottles. The specific gravity of fine aggregates found in Pune regionvaries from 2.6 to 2.8.b) Grading of coarse aggregate: The coarse aggregate grading limits are given in IS383 – 1970 - table 2, Clause 4.1 and 4.2 for single size aggregate as well as gradedaggregate. The grading of coarse aggregate is important to get cohesive & denseconcrete. The voids left by larger coarse aggregate particles are filled by smallercoarse aggregate particles and so on. This way, the volume of mortar (cement-sand-water paste) required to fill the final voids is minimum. However, in some cases gapgraded aggregate can be used where some intermediate size is not used. Use of gap-graded aggregate may not have adverse effect on strength.By proper grading of coarse aggregate, the possibility of segregation is minimised,especially for higher workability. Proper grading of coarse aggregates also improves   40  
  41. 41. the compactability of concrete.c) Shape of coarse aggregate: Coarse aggregates can have round, angular, orirregular shape. Rounded aggregates because of lower surface area will have lowestwater demand and also have lowest mortar paste requirement. Hence they will resultin most economical mixes for concrete grades up to M35. However, for concretegrades of M40 and above (as in case of max size of aggregate) the possibility of bondfailure will tilt the balance in favour of angular aggregate with more surface area.Flaky and elongated coarse aggregate particles not only increase the water demandbut also increase the tendency of segregation. Flakiness and elongation also reducethe flexural strength of concrete. Specifications by Ministry of Surface Transportrestrict the combined flakiness and elongation to 30% by weight of coarse aggregates.d) Strength of coarse aggregate: Material strength of coarse aggregate is indicatedby crushing strength of rock, aggregate crushing value, aggregate impact value,aggregate abrasion value. In Maharashtra the coarse aggregates are made of basaltrock, which has strengths in excess of 100 N/mm2. Hence aggregates rarely fail instrength.e) Aggregate Absorption: Aggregate can absorb water up to 2 % by weight when inbone dry state, however, in some cases the aggregate absorption can be as high as 5%.Aggregate absorption is used for applying a correction factor for aggregates in drycondition and determining water demand of concrete in saturated surface drycondition.Decision Variables in Mix DesignA. Water/cement ratio B. Cement content C. Relative proportion of fine & coarseaggregates D. Use of admixturesA. Water/cement ratioWater to cement ratio (W/C ratio) is the single most important factor governing thestrength and durability of concrete. Strength of concrete depends upon W/C ratiorather than the cement content. Abram’s law states that higher the water/cement ratio,lower is the strength of concrete. As a thumb rule every 1% increase in quantity ofwater added, reduces the strength of concrete by 5%. A water/cement ratio of only0.38 is required for complete hydration of cement. (Although this is the theoreticallimit, water cement ratio lower than 0.38 will also increase the strength, since all thecement that is added, does not hydrate) Water added for workability over and above   41  
  42. 42. this water/cement ratio of 0.38, evaporates leaving cavities in the concrete. Thesecavities are in the form of thin capillaries. They reduce the strength and durability ofconcrete. Hence, it is very important to control the water/cement ratio on site. Everyextra lit of water will approx. reduce the strength of concrete by 2 to 3 N/mm2and increase the workability by 25 mm. As stated earlier, the water/cement ratiostrongly influences the permeability of concrete and durability of concrete.B. Cement contentCement is the core material in concrete, which acts as a binding agent and impartsstrength to the concrete. From durability considerations cement content should not bereduced below 300Kg/m3 for RCC. IS 456 –2000 recommends higher cementcontents for more severe conditions of exposure of weathering agents to the concrete.It is not necessary that higher cement content would result in higher strength. In factlatest findings show that for the same water/cement ratio, a leaner mix will give betterstrength. However, this does not mean that we can achieve higher grades of concreteby just lowering the water/cement ratio. This is because lower water/cement ratioswill mean lower water contents and result in lower workability. In fact for achieving agiven workability, a certain quantity of water will be required. If lower water/cementratio is to be achieved without disturbing the workability, cement content will have tobe increased. Higher cement content helps us in getting the desired workability at alower water/cement ratio. In most of the mix design methods, the water contents toachieve different workability levels are given in form of empirical relations.Water/cement ratios required to achieve target mean strengths are interpolated fromgraphs given in IS 10262 Clause 3.1 and 3.2 . The cement content is found as follows:-Cement content (Kg/m3) =Water required achieving required workability (Lit/m3)Water/cement ratioThus, we see that higher the workability of concrete, greater is cement contentrequired and vice versa. Also, greater the water/cement ratio, lower is the cementcontent required and vice versa.C. Relative proportion of fine, coarse aggregates gradation of aggregatesAggregates are of two types as below:a. Coarseaggregate(Metal): Theseareparticlesretainedonstandard IS 4.75mm sieve.b. Fine aggregate(Sand): These are particles passing standard IS 4.75mm sieve.   42  
  43. 43. Proportion of fine aggregates to coarse aggregate depends on following:i. Fineness of sand: Generally, when the sand is fine, smaller proportion of it isenough to get a cohesive mix; while coarser the sand, greater has to be its proportionwith respect to coarse aggregate.ii. Size & shape of coarse aggregates: Greater the size of coarse aggregate lesser isthe surface area and lesser is the proportion of fine aggregate required and vice versa.Flaky aggregates have more surface area and require greater proportion of fineaggregates to get cohesive mix. Similarly, rounded aggregate have lesser surface areaand require lesser proportion of fine aggregate to get a cohesive mix.iii. Cement content: Leaner mixes require more proportion of fine aggregates thanricher mixes. This is because cement particles also contribute to the fines in concrete.D. Use of admixturesNow days, admixtures are rightly considered as the fifth ingredient of concrete. Theadmixtures can change the properties of concrete. Commonly used admixtures are asfollows:i. Plasticisers & superplasticisersii. Retardersiii. Acceleratorsiv. Air entraining agentsv. Shrinkage compensating admixturesvi. Water proofing admixturesi. Plasticisers & super plasticisersPlasticisers help us in increasing the workability of concrete without addition ofwater. It means that we can achieve lower water/cement ratio without reducing theworkability at the same cement content. Cement particles tend to form flocs trapping apart of mixing water in them. Hence not all the water added is useful for generatingworkability. Plasticisers work as dispersion agents (de flocculent) releasing the watertrapped in the flocs resulting in workability. Use of plasticisers is economical as thecost incurred on them is less than the cost of cement saved; this is more so in concretedesigned for higher workability.Compatibility of plasticisers with the cement brand should be checked before use.Also plasticiser should not be added in dry concrete mix.   43  
  44. 44. Plasticizers are used for moderate increase of workability whereas super plasticizersare used where very large increase in workability is required. Plasticizers are normallylignosulphonated formaldehydes and are normally added in small dosages. This isbecause large dosage can cause permanent retardation in concrete and adversely affectits strength. Super plasticizers are naphthalene or melamine based formaldehyde.They can be used in large dosages without any adverse effect on concrete. This iscontrary to popular perception that term super plasticizers means more potent, hencelower dosage is required when compared to normal plasticizers. In practice superplasticizers are used in large dosages for generating higher workability and betterslump retention. Compatibility of plasticizers with cement should be ascertainedbefore use in concrete. Since action of plasticizers is based on ionic dispersion certainplasticizers are more effective with certain cements, thus requiring lower dosages.Non-compatible plasticizers if used, will not adversely affect the concrete, but its highdosage will make it uneconomical for use.ii. Retarders:They are used for retarding (delaying) the initial setting time of concrete. This isparticularly required when longer placing times are desired as in case of ready mixedconcrete. Retarders are commonly used to prevent formation of cold joints whencasting large concrete. Retarders are normally added in lower dosages as largedosages can cause permanent retardation in concrete. Retarders are recommended incase of hot weather concreting to prevent early loss of slump. It is important to notethat retarders reduce early strength of concrete e.g. 1-day and 3-day strength.However, 28 days strength is not affected.iii. AcceleratorsThey are used for accelerating the initial strength of concrete. Typical acceleratorsincrease the 1-day (up to 50 %) and 3-days (up to 30 %) strength of concrete. Most ofthe accelerators show little increase for 7 days strength. For this reason, acceleratorsare commonly used in precast concrete elements for early removal of moulds.Accelerators may not be much useful for early deshuttering where early strengths arerequired in range of 5 to 7 days. This is because accelerators are expensive and theirability to increase strengths decreases after 3-5 days. A better option for earlydeshuttering would be the use of plasticizers, reducing the water/cement ratio andachieving a higher grade of concrete. It is believed that accelerators may causeretrogression of strength after 28 days when compared with normal concrete.   44  
  45. 45. Concrete Mix Design MethodsThe basic objective of concrete mix design is to find the most economical proportions(Optimisation) to achieve the desired end results (strength, cohesion, workability,durability, As mentioned earlier the proportioning of concrete is based on certainmaterial properties of cement, sand and aggregates. Concrete mix design is basically aprocess of taking trials with certain proportions. Methods have been developed toarrive at these proportions in a scientific manner. No mix design method directlygives the exact proportions that will most economically achieve end results.These methods only serve as a base to start and achieve the end results in thefewest possible trials.The code of practice for mix design-IS 10262 clearly states following: - The basicassumption made in mix design is that the compressive strength of workableconcretes, by and large, governed by the water/cement ratio. Another most convenientrelationship applicable to normal concrete is that for a given type, shape, size andgrading of aggregates, the amount of water determines its workability. However, thereare various other factors which affect the properties of concrete, for example thequality & quantity of cement, water and aggregates; batching; transportation; placing;compaction; curing; etc. Therefore, the specific relationships that are used inproportioning concrete mixes should be considered only as the basis for trial, subjectto modifications in the light of experience as well as for the particular materials usedat the site in each case. Different mix design methods help us to arrive at the trial mixthat will give us required strength, workability, cohesion etc. These mix designmethods have same common threads in arriving at proportions but their method ofcalculation is different. Basic steps in mix design are as follows:Find the target mean strength.Determine the curve of cement based on its strength.Determine water/cement ratio. Determine cement content.Determine fine and coarse aggregate proportions   45  
  46. 46. BATCHING PLANT   46  
  47. 47. PROJECT EXECUTIONMETHOD STATEMENT FOR CIVIL AND MECHANICAL 1. METHOD STATEMENT FOR CIVIL METHOD STATEMENT FOR SURVEY WORKS OBJECTIVE: To formulate guidelines for Setting out and routine surveyworks REFERENCE: 1. Drawing 2. Technical Specifications for Civil works 3. Inspection and test plan 4. Survey Layout showing control stations MAJOR EQUIPMENTS: Calibrated Auto - level, Theodolite (LC-1"), Total Station and necessary measuring tools METHOD STATEMENT FOR BUILDING UP OF PILES UPTO CUTOFF LEVEL OBJECTIVE: Building up of Plies up-to cut-off levels REFERENCE: 1. Drawing 2. Technical Specifications for Civil works 3. Technical Data sheet of Nitobond EP METHOD STATEMENT FOR REINFORCEMENT WORK 1. OBJECTIVE: This procedure covers method for cutting, bending and tying of reinforcement and inspection of works. 2. REFERENCE: Reinforcement placing and handling shall be as per IS-456 MAJOR EQUIPMENTS: Bar cutting & bending machines, rebar tying tool. METHOD STATEMENT FOR FORMWORK 1. OBJECTIVE: This Procedure covers fixing and removal of formwork and checking of formwork. 2. REFERENCE: 1. Approved Drawings   47  
  48. 48. 2. IS 456 & IS 6461(Part 5) 3. Tender Document METHOD STATEMENT FOR BOLTS PROCUREMENT & FIXATION 1. OBJECTIVE: This Procedure covers procuring and fixing of bolts. 2. REFERENCE: 1. Tender Specification 2. Approved Drawings METHOD STATEMENT FOR CONCRETING WORKS 1. OBJECTIVE: This Procedure covers fixing and removal of formwork and checking of formwork. 2. REFERENCE: 1. Tender Specification 2. Approved Drawings 3. IS 10262, IS 3370 & IS 456 4. IS 383 METHOD STATEMENT FOR BACKFILLING 1.OBJECTIVE: The scope of back-filling covers the filling in plinths, pits, trends, depressions in layers 200mm thick including watering and compaction by Roller / plate compactor. 2. REFERENCE: 1. Drawing 2. Bill of Quantities METHOD FOR REINFORCEMENT WORK1.All reinforcement shall be placed above the ground by using wooden sleepers orconcrete blocks.2.For reinforcement, care shall be taken to protect the reinforcement from exposure tosaline atmosphere during storage, fabrication and use.3.Against requirement from site, bars shall be cut and bent to shape and dimension asshown in bar bending schedule based on Good For Construction (GFC) drawings.   48  
  49. 49. 4.Reinforcement shall be tied as per the latest GFC drawing and any extra barsprovided at site shall be recorded in the pour card/ lap register.5.Unusable cut rods and scrap reinforcement shall be properly placed at yard.Bar Bending Schedule:1.Prepare bar bending schedule based on the latest GFC drawings and to be submittedto Engineer for review2.Bar bending schedule shall clearly specify the following:a) Bar dia.b) Numbers.c) Cut-lengths.d) Shapes.3.Bar bending schedule shall take into account the following field/ designrequirement.a) Desirable lap locations and staggering of laps.b) Lap lengths.c) Development length/ Anchorage length.Cutting, Bending and Placing:1.All reinforcement shall be free from loose mill scales, loose rust and coats of paints,oil, mud or any other substances which may destroy or reduce bond. Use wire brushto clean the reinforcement.2.Cutting and bending shall conform to the details given in the approved bar bendingschedule. a) Cutting of Rebar by heat is not permitted, only cutting by grinding or shearing ispermitted. b) No heating is allowed to facilitate bending of Rebar.3.Place the reinforcement as per GFC drawings ensuring the following aspectsproperly.a) Type & size of bar. b) Number of bars.c) Location and lengths of laps, splices.d) Curtailment of bars.e) In two way reinforcement, check the direction of reinforcement in various layers.f) Adequate number of chairs, spacer bars and cover blocks.   49  
  50. 50. g) Size of cover blocks.h) All the bars shall be tied with double fold 18g soft GI annealed binding wire.4.Reinforcement may be placed with in the following tolerance whenever required:a) for effective depth 200mm or less ±10mm.b) for effective depth more than 200mm ±15mm.c) The cover shall in no case be reduced by more than one third of the specified coveror 0 /+ 10mm.d) The cover should suit various cover requirement as per Drawing Notes.5.The sequence of reinforcement shall be correlated with fixing of inserts, sleeves,conduits, anchors and formworks.6.In walls, place accurately bent spacer bars wired to vertical or horizontal barsbetween successive rows.7.No steel parts of spacers sure allowed inside the concrete cover. Spacer blocks madefrom cement, sand and small aggregate shall match the mix proportion of thesurrounding concrete. Alternatively PVC cover blocks of approved make can be used.8.Spacers, cover blocks should be of concrete of same strength or PVC9.Spacers, chairs and other supports detailed on drawings, together with such othersupports as may be necessaray, should be used to maintain the specified nominalcover to the steel reinforcement.10.Spacers or chairs should be placed at a maximum spacing of 1.0 mtr and closerspacing may sometimes be necessary.11.All reinforcement shall be placed and maintained in the positions shown in thedrawing by providing proper cover blocks, spacers, Supporting bars.12.Rough handling, shock loading (Prior to embedment) and the dropping ofreinforcement from a height should be avoided. Reinforcement should be securedagainst displacement. METHOD FOR FORMWORKPre Check1.Check if the shutters are properly cleaned by removing the concrete/ mortar andprotruding nails.   50  
  51. 51. 2.Formwork shall be made to the exact dimensions within the permissible tolerancesas mentioned below.3.Required thickness and quality of plywood conforming to IS 6461 shall be used tomeet the requirements of design and surface finish.4.For beam bottom & sides, proper size of timber at required spacing shall beprovided to take the design loads/ pressure considering sleeves, conduit anchors &inserts.Erection of formwork5.Sufficiently rigid and tight to prevent the loss of grout or mortar from the concrete.6.Capable of providing concrete of the correct shape and surface finish within thespecified tolerance limits.7.Soffits forms capable of imparting a camber if required.8.The formwork may be of timber, plywood,steel,plastic or concrete depending uponthe type of finish specified.9.Erect staging/shuttering as per drawing/sketches in such a way that deshuttering canbe done easily including provision for repropping, if planned.10.Check the location, line,level,plumb and dimensions of the formwork to ensurethat the deviations are within the permissible limits.11.Provide bracing at proper places & intervals as specified by the manufacturer or asper formwork scheme to take care of lateral loads.12.Apply mould oil/other coatings as release agents before reinforcement steel isplaced.13.Wire ties passing through beams,columns and walls shall not be allowed .In theirplace bolts passing through sleeves shall be used.For liquid retaining structures,sleeves shall not be provided for through bolts.14.Check all the shutters are properly aligned and fixed firmly with required lateralsupports and ties.15.Check all the spanning members have proper bearing at the supports.16.Wedges or jacks shall be secured in position after the final check of alignment.17.Forms shall be thoroughly cleaned of all dirt, mortar and other matters such asmetals, blocks, saw dust and foreign materials before concreting if required throughclean-out openings.18.Check all the gaps/openings are properly closed to avoid leakages.   51  
  52. 52. 19.Check all the inserts/embedments and openings are exactly placed as per thedrawings.20.In case of leakages, bulging and sagging immediate actions shall be taken bytightening wedges or adjusting by jacks which must be done before the concrete takesits initial set.Removal of Forms21.Formwork components shall not be dropped but shall be lowered without damageto the components and structures. All the removed formwork materials shall bethoroughly scarped, cleaned immediately and stacked properly for reuse.22.All forms shall be removed after the minimum period stipulated mentioned belowwithout damage to the concrete including removal without shock as per IS 456 METHOD FOR BACKFILLING1. Backfilling area shall be free from foreign matters (ie. wooden scraps , plywoodpieces rebar bits etc) and tie rods recesses shall be rendered with polymer based nonshrink compound with a subsequent application of curing compound on them.2.Filling around foundation or other places indicated shall be done with approvedmaterial obtained from excavation or approved materials brought from out side.3.The material shall be good quality soft or hard murrum or Panna sand or otherapproved back filling material.Back filling soil shall be free from black cotton soil.4.Filling shall be done in layers not exceeding 20 cms thick and each layer shall bewatered adequately and consolidated properly by rollers or pneumatic rammers 8 to10 tonnes wherever conditions permit. If it is not possible, the consolidation shall bedone by hand rollers/ heavy pneumatic/ hand rammers/ plate compactor.5.The surface of the filling shall be finished to lines and levels as required.6.The approved materials shall be plced in layers, not exceeding 200mm in depthbefore compaction and shall be compacted to minimum 95% dry density. Layersplaced in the top 300mm of the fill shall be compacted to 98% of maximum drydensity.No of Samples:(i)For foundation filling - one for every 10 foundation for each compacted layer.(ii)For area filling one for every 1000 sqm area for each compacted layer.   52