Quality assurance in highwayconstruction projectsMithilesh Gawali11MSin Construction Engineering and Management (Student), University of Illinois-Urbana-ChampaignAbstractQualityControl & Assurance is an integral part in construction projects, mainlyhighways, due to the sheer amount of investment made in these projects. Thehigh number of stakeholders and consumers of this critical piece ofinfrastructure, has made it essential to maintain the quality during and afterconstruction. The necessity of maximizing profits and improvements inmanagement science has compelled the construction industry to invest in qualityassurance. Additional motivation came from the recent success of managementtechniques like Total Quality Management (TQM) in other industries likemanufacturing & services. Thispaper will discuss the need for a quality assurance program and how it is setupin the construction industry, primarily in highway projects. The paper studiesthe present models and measures for quality control and determines whetherthere are any other methods available which can be more cost efficient. New andinnovative methods of ensuring quality control are presented.
Lastly, applicationof quality assurance in Design-Bid type of contract is presented with respectto their methods and challenges. IntroductionAmajor factor of USA’s industrial success during the world war wasimplementation of statistical process control procedures required formanufacturing weapons and equipment. Japan adopted these techniques ofstatistical control over the manufacturing line where as USA shifted theirfocus to profits & productivity. This led to a stagnation in qualitymanagement in the 1960’s & 70’s 2. The Japanese on the other hand weresuccessful in delivering quality consumer goods at a lower price because ofcontrol over the manufacturing processes. Today, globalization has increasedthe competition amongst many industries which is recognized as one of thecompelling factors for pursuing continuous improvement 3. Improved efficiencyachieved due to improved processes has enabled smaller firms in lesscompetitive environments to achieve higher profit margins. The relative powerof a consumer is enhanced because of the paradigm shift witnessed due toglobalization 4.
UnitedStates transportation has a value of approximately $7.0 Trillion 1. The majorchallenges are to preserve and protect the quality of this huge investment.Also, the transportation industry is growing with time and the future has itsown sets of challenges like growth in traffic, congestion on both highways& city roads, and concerns regarding environmental impacts of highwayconstruction.
The shrinking investment into maintaining & enhancing thecritical infrastructure is also a major issue. These factors coupled withdecreasing workforces & a very old highway infrastructure makes quality avery important factor. These issues will require noteworthy consideration toguarantee that we get the best possible performance from the highways plannedin future. History of Quality Assurance inTransportation IndustryIntransportation construction, the American Association of State Highway Officials (AASHTO) Road Test of 1956 is the first documented event ofincorporation quality assurance techniques in construction of highways 5. Astatistical specification for Hot-Mix Asphalt construction (HMA) wasimplemented by Bowers & Lane in 1976 6.
Around the same period, manyindustries were implementing highway construction specifications while consideringstatistical quality control 7. The core of quality assurance systems hasremained the same since the 70’s. But the drive for implementation of astatistical process control & quality assurance program comes from otherforces which are either inherent to HMA manufacturing or related to thesocio-economic environment in which it operates. Oneof the most noticeable internal force has been the development of Superpave Mixdesign method by the Strategic Highway research program.
The essence of a SuperpaveMix-Design is a production control system which allows the designed propertiesto be attained. This system takes asphalt, binder, aggregate selection in mixdesign along with traffic and climatic control. Thereby, each superpave designis catered to the specific conditions the roadway is going to be exposed towhich ensures that the designed specifications are met. The Federal HighwayAdministration literature states that “By allowing highway agencies todetermine if the mix delivered to the jobsite matches the mix designed in thelaboratory, the QC/QA procedures will ensure that Superpave pavements performas expected.” 8 The shortage of raw materials in addition to improvements inrecycling technology have realized the inclusion of recycled asphalt pavement(RAP) in the HMA industry. The use of RAP has increased the importance ofstatistical process control in the HMA industry due to it’s the increasedrequirements of attention to manufacturing process because of the difficulty tocontrol the recycling process. The changed ratios in asphalt binders andrecycled materials have increased the demand of a controlled process to attainthe design requirements. The FHWA & AASHTO also now recognize the value ofTotal Quality Management (TQM) and its contributions to quality assurancesystems.
External Factors Driving QA programsThemost important external factor which drives the implementation of qualityassurance programs is the enhanced competition for taxpayers’ money. A majorpart of this money is distributed amongst many other government functions likeeducation, defense, & healthcare. This makes it essential to make efficientuse of the funds allotted and maximize the value of gained from spending eachdollar. Use of modern management systems is the key to account for the spendingof public funds. Additional motivation for quality-management systems arosefrom the successful implementation of TQM in industries like services &manufacturing. The concepts of TQM are present in other industries as well inform of lean production (lean construction), just-in-time systems &six-sigma processes. The National Quality Initiative (NQI) incorporates the TQMinitiatives taken by the construction industry, specially transportationconstruction. The last and a major factor is a very fast growth of informationtechnology tools making the statistical process control easier.
This is due tothe abundance of real-time data to all the entities involved in the process ofproduction. With more developments in the IT sector, the processing speeds andthe connectivity amongst everyone is increasing making it easy to manage theflow of data required for monitoring the manufacturing processes. Incomparison, the pre-computer era called upon for exhaustive computationalresources for statistical control, whereas, now the required effort is easierand more cost effective. Some of the most difficult challenges inimplementation of QA programs can now be easily solved by use of Computers,internet, GPS etc. Quality Assurance ProgramAASHTOdefines quality assurance as “(1) All those planned and systematic actionsnecessary to provide confidence that a product or facility will performsatisfactorily in service; or (2) making sure the quality of a product is whatit should be.” 9 The key documents act as the guidance for implementingQuality Assurance programs are the 1992 NQI report “National QualityImprovement Task Force Report on Quality Procedures for Highway Construction”.10 This document defines the vision for the projects & sets thefoundation necessary to aid the efforts to achieve the vision.
The other majordocument required is “AASHTO Implementation Manual for Quality Assurance” whichdefines a recommended structure for the QA program. 11Traditionally,the term QC/QA was used wherein QC (Quality Control) referred to the role of acontractor and QA (Quality Assurance) was the role of an agency. The term meantthat QC & QA were separate terms.
However, Quality Assurance implies an overall system for promising projectquality with Quality control being one element of a widespread system. Aquality assurance system is comprised of components necessary to make sure thatthe quality of a service or a product is acceptable to the customer or theclient. The components are as follows:1) Quality Control:”The sum of the activities performed by either the contractor or manufacturer/producerto make sure that a product meets contract specific requirements.
” 12. Themain purpose of QC is to provide information to the owner/contractor on a timeto time basis to help him in monitoring & guiding production or positioningprocesses. Data obtained from QC can also be used for final acceptancedetermination by comparing the required quality characteristics to the measuredones. For the QC data to be accepted for acceptance, it should be subjected tovalidation by agency verification test results. External inspectors orconsultants can be employed to conduct Quality Control inspections &related testing. But this does not replace the agency’s responsibility ofverifying the results. The minimum level of documents to be provided for QC isspecified by the agency and should be fulfilled by the contractor/manufacturerand related authorities. Typically, QC documentation includes the testingconditions, results & comparison with benchmarks set forth in the contractdocuments.
2) Agency Acceptance:”The acceptance system defines a set of rational procedures to be used by theagency to determine the degree of compliance with contract requirements and thevalue of the product delivered by the contractor”. 13 This is the responsibilityof the customer. Agency Acceptance includes few basic things: a. SupervisingContractor QC; b. Acceptingsampling and testing; c. Verificationof QC datad. QualityMeasures of acceptance: Limits like Percent-within-limits (PWL) can be used fordata which has a wide acceptance range and a small sample size.
If the data isnot suitable for PWL, then the data is compared against engineering limits foracceptance.e. Inspection3) Independent Assurance:”Activities that are unbiased & independent evaluation of all sampling andtesting procedures used in the acceptance program”. 14Themotive of an IA system is to ensure the consistency of data used by the agencyto determine acceptance. This is necessary to ensure that any kind of testingdone by the agency and design builder or the contractor follows specificstandards, is done by qualified personnel, and has used proper calibratedequipment which functions without errors.4) Dispute Resolution:”Formal Procedure used to resolve conflicts resulting from discrepanciesbetween the Agency’s & Contractor’s results of sufficient magnitude toimpact payment.
” 15 This process should be an unbiased one. For addressingdisputes related to testing, the samples used in the testing should be storedand retained in tamperproof containers and security seals should be placed onthem. The testing should be done by third party laboratories which arecertified.5) Personnel Qualification:The requirements of the federal regulation are that qualified personnel must beinvolved in both agency acceptance & independent assurance. The contractdocuments in case of a design-build type of contract state the minimumqualifications required for personnel performing QC sampling, inspection . The quality management personnel should have a thorough comprehensionof QA principles and have an experience of working under those specifications. 6) Laboratory Accreditation:All laboratories that are involved in the testing processes in the acceptanceprograms must be accredited. The accreditation is to be carried out through theAASHTO Accreditation Program (AAP).
16 The laboratories that are focused onlyon testing for process control are not needed to be certified, but certainagencies have their own standards which require a certified laboratory for alltasks. Hence it becomes important for a laboratory to become certified. 7) Partnering:”A formal, organized method of improving communication on a project seeking tominimize disputes, claims & establish a shared commitment to solve problemin a timely & cost-effective manner” 17. There should be a minimumpartnering objective to avoid situations where the relationships between thecontractor and the owner which can cause impediment in achieving the highestpossible quality. Thesecore elements of a QA program are applicable to any kind of projectirrespective of the delivery method of the project.
Quality Assurance MethodsQualityassurance methods are generally grouped into the following categories: MaterialPrequalification, qualification of requirements (for both facilities ), requirements of submittals, testing of materials, materialssampling, compliance certificates, inspection & warranties. The methods areto be used in combination rather than just alone to realize the level ofquality assurance required. The decisions taken after a quality assuranceprogram/test are based on the use of application of item. The decisions alsoare dependent on the consequences of failure of that material on the entireproject.
Since construction materials, their manufacturing & testing playsand important role, material prequalification, methods of qualification ofpersonnel & qualification of personnel dealing with them are discussed indetail in this paper.Material PrequalificationAuthorized Materials ListCreatinga list of specific materials from various vendors would make sure you alwayshave a list to refer to for acquiring materials of a required quality. Thisinvolves approaching the vendors and getting samples of mass produced items,which are to be tested at certified facilities. Before the projects, theprequalified items are to be tested again and field performance evaluations inspecific project conditions are to be performed to ensure specific quality ismet. Example of eligible materials is concrete components, ready mix concrete,anchorage systems, safety devices, barrier systems.
Authorized Materials Source ListThesources of materials also play an important role in the quality control. Thislist can be compiled in the same way as the material list by testing the samematerials available at different sources. Materials from these authorizedmaterial source catalogues should be preferred for use wherever possible.Examples of such sources are specific location of soil to be used as abackfill, or use of lime materials in soil stabilization. Authorized to deliver Material ListThisis a list of materials which do not require inspections according to specificprojects but only a source inspection is necessary. Source inspection for thesematerials must be done at regular intervals irrespective of the projectsschedules.
Examples of these materials are sign structures or epoxy coatedrebars.Products Manufactured to NationalQuality Standards Theseproducts are specifically manufactures in a way that they meet thespecifications of organizations like ASTM, AASHTO, AISC. These standards includecriteria which meet national quality standards.
These standards can be easilyintegrated easily within any agency standards by just incorporating the number,title or a designation given by the industry. They also provide quality desiredfor almost all purposes. These types of materials should be included as much aspossible owing to their capacity to perform according to specifications and arecost effective alternatives to preparing project specific specifications.Department Furnished MaterialsThematerials furnished by the contractor which will be incorporated in the projectare included in this list.
These can be department owned or departmentdesigned. Examples of these materials include recycled materials, temporarytraffic signs, flashing beacons etc. There are no quality assurancerequirements available in the specifications for department furnished material.Qualification Requirements forFacilitiesPrefabrication AuditTheagency should perform a prefabrication audit to evaluate a fabricatorsprocesses and his whether he has the resources to deliver the productsaccording to the quality mentioned in the specifications.
This is mainlyapplicable to materials which are custom fabricated. Rejection of the materialafter field testing is both costly & time consuming and can affect thequality of the delivered project. The producer’s capability to perform is givencan be assured by the production facility audit. Periodic audit of anyfabricator makes them aware of the responsibility they have to maintain projectquality control. Authorized Facility Audit ListingUsinga system based approach to assess the fabricator’s quality control process, theAuthorized facility audit listing (AFAL) is created as list of facilities whichare audited by the agency. This process evaluates the ability of the fabricatorto fabricate products matching the specifications provided in the contractualdocuments in terms of the process control maintained at his facility.Facilities manufacturing iems like structural precast concrete, welded steeltrusses, lighting poles, steel pipe piling are available in the AFAL.
Authorized Laboratory ListTheagency maintains a list of independent laboratories which are certified toperform testing on elements like reinforcing steel, splices, guest plates. Thetests performed in such laboratories are production tests for barreinforcements, tensile tests for head bar reinforcements & similar tests.This list helps the agency & contractor by providing them access tolaboratories which can perform tests without disputes amongst them.Authorized LaboratoryFora laboratory to be authorized for testing, it must meet the following prerequisites:1) Becapable of performing tests set forth by the respective agency2) Becurrently accredited by AASHTO Accreditation Program (AAP), the relevant agency’slaboratory accreditation system or a comparable accreditation society which isrecognized by the NCLA (National Co-Operation for laboratory Accreditation.3) Mustparticipate in the lab assessment & proficiency sample services byrecognized organizations dealing with testing of construction materials4) Mustbe recognized & accepted as an organization which provides product safetytesting & certification.
Thecompetence of a laboratory in performing specific test methods is important tomake use of that laboratory for a Quality Assurance program. This can bedemonstrated by having the following personnel & documentation: 1) Supervisorswith minimum 3years of experience of testing construction materials used inhighways2) Routinelaboratory assessments made every 3 years3) Trainingrecords demonstrating that the personnel are properly trained & routinelyevaluated, qualified to perform the specific test method.4) Authentictest results showcasing previous experience in successful performance of thatmethod of testing5) Aformal reporting process for results6) Records& a third party certificate showing calibration of the equipment needed fortesting after every 2 years. Authorized PlantAnyplant or facility must be certified & authorized to an accepted standard.Production at any plant can begin only when the authorization process has beencompleted. Each agency might have their own criteria for certifying a plantwhich needs to be met with.
Qualification Requirement forContractorsToensure that work is performed by competent & qualified contractors only,the contractors need to be certified by a recognized standard. For example awelding contractor should be certified by AWS (America Welding Society)Qualification Requirements forPersonnelThe2 main types of personnel that need to be certified are:1) Sampling,Testing & Inspection Personnel2) Installer/Applicator/ErectorPersonnelThecertification of these workers must be completed before they start working.Testers are to be certified so that the inspection & testing data used inthe acceptance phase is agreed upon without dispute. The installers are to becertified so that they have proper training before executing work to getproducts according to the required specifications.