GOVERNMENT OF TAMIL NADU HIGHWAYS DEPARTMENT HIGHWAYS RESEARCH STATION Training program for newly recruited Assistant Engineers

Quality control and Assurance of Highway Projects From 17.05.2016 to 20.05.2016

QUALITY Totality of features and characteristics of a product for service that bears on its ability to satisfy the projects functional requirements. The quality of output is always agreed upon between the contractor and the employer The quality objective is to achieve zero defects with best quality of the project works. Possible only by ensuring quality control at every stages during progress of construction. Quality is conformity to standards and requirements to achieve excellence and economy.

QUALITY CONTROL The operational techniques or a system of maintaining standards by reviewing, checking, inspecting and testing Product oriented and focuses on defect identification Set of activities to ensure quality in the work. The activities focus on identifying defects in the actual work done.

QUALITY ASSURANCE All actions taken to ensure that standards and procedures are followed to and that delivered products or services meet performance requirements. Process oriented and focuses on defect prevention Set of activities to ensure quality in the process by which works are done. The goal of QA improve and develop test processes so that defects do not arise when the work is being done. The well designed quality assurance system will provide confidence that the project outputs will fulfil all the requirements for which it is being planned.

Quality assurance system basic parameters. Site documents Mandatory and optional testing Availability of field and departmental laboratories Manufacturing test certificates Departmental team inspections Checklist guide for works Site inspections Post quality testing of finished works Quality certification Monthly reporting and review meetings

Benefits of QC/QA Improved quality Uniformity Economic utilization of materials Reduction in user cost Additional cost – Fraction of resulting benefits 0.5 to 1% of construction cost

Requirements for good QC practices Well prepared estimates based on field tests and established test procedures Provision for quality control in estimates Staff with adequate training and knowledge Adequate QC equipments and lab facilities Periodical review and appraisal of QC data Updating of knowledge

Causes of non-conforming works Lack of training Lack of resources Poor communication / incomplete instructions Inadequately defined work practices Inadequate supervision Inadequate planning and Non maintenance of records Lack of involvement

Quality control methodology Control of Materials Test Procedure Frequency Acceptance Criteria Corrective actions Equipments and calibration Documenting the results

Estimate stage considerations Get required test results and data (CBR, BBD & Traffic census) Avoid manipulation and errors Make uniform provisions along and across the road Adequate provisions for shoulder and drain Include geometric components and corrections

QC requirements Testing of materials Manufacturing/mixing process Tests during laying/finishing

QC requirements Material to be used Methodology to be adopted Works to be performed Shall be as per specifications

MORTH Section 900 (QC) Highlights Field laboratory manned by qualified Civil Engineer shall be provided by the contractor Contractor shall carry out QC tests on the materials and work to the stipulated frequency The contractor shall provide necessary cooperation and assistance in obtaining samples for tests and carrying out field tests including lab equipments, transportation, consumables and personnel. Works found falling short of quality shall be rectified by the contractor at his own cost The cost of the above provisions and services shall be deemed to be incidental to work

Control of Alignment, Level and Surface Regularity Works shall conform to the lines, grades and cross sections shown in the drawings The edges of the carriageway shall be correct within a tolerance of ±10 mm, for lower layers of pavement it is ±25 mm The levels of subgrade and other pavement layers shall not vary from those calculated with reference to the LS & CS of the road swhon on the drawings For subgrade permitted tolerance in surface levels is ±20 mm, for flexible pavement sub base it is ±10 mm, for manually laid base course it is ±15 (machine laid ±10 mm) and for bituminous base/binder course/wearing course it is ± 6 mm For BC surface the permissible value of roughness is 2000 mm/km.

Typical flow chart for quality control in road works Source: Quality Assurance Handbook for Rural Roads

Typical flow chart for quality control in road works Source: Quality Assurance Handbook for Rural Roads (contd...)