Technical Advisories
Engineering Inspection of Highway and Street Construction on Federal-Aid Projects
T 5080.1
May 18, 1979
Par.
- Purpose
- Background
- Description
- Recommendation
PURPOSE. To provide guidance to engineers involved in making construction inspections on Federal-aid highway projects.
BACKGROUND
The Federal Highway Administration (FHWA), through FHPM 6-4-2-8, Inspection of Federal-aid Construction Projects, requires sufficient inspection of Federal-aid highway construction work to assure that each project is completed in reasonably close conformance with the approved plans and specifications, including authorized changes and extra work. Furthermore, FHWA is charged with the responsibility to evaluate the performance, adequacy, and effectiveness of the State highway agencies in controlling the quality of such work.
The FHWA field personnel involved in highway construction inspections have the responsibility of evaluating construction activities and procedures to assure a quality product. With smaller projects being awarded and the increasing number of nonconstruction items requiring coverage, the FHWA field engineer must manage available time in the most efficient and effective manner to accomplish this responsibility.
DESCRIPTION
Within highway construction projects, there are certain types of construction elements that contribute to the end product. Proper design and satisfactory construction of these elements will generally result in a product that will perform at the desired level of service.
A list of key construction elements, including quality factors within those elements, have been developed. The attached table addresses six highway construction elements including bituminous pavement, rigid pavement, bridge deck, structural concrete, base course, and embankment construction. The quality factors are items that were identified by selected FHWA field and Washington Headquarters personnel and affect the durability and continued satisfactory performance of a product.
RECOMMENDATION
The foremost goal of a construction inspection is to provide a quality highway product. It is important that engineers making construction inspections use their knowledge of local circumstances to determine where their available inspection time would be most productive. Therefore, it is recommended that the attached table be used as a management tool to supplement the engineer's plan in performing quality construction inspections.
In the table below, the quality factors are shown in three groups for each construction element. The groupings represent an order of significance. For the engineer's consideration in managing available inspection time, it is recommended that those quality factors listed in Group I be considered for inspection first. If a more detailed inspection is being conducted, the engineer should expand the inspection to include those quality factors listed in Groups II and III.
/S/
R. D. Morgan
Associate Administrator for
Engineering and Traffic Operations
Key Construction Elements and Quality Factors
ELEMENT | GROUP 1 | GROUP II | GROUP III | GROUP III |
---|---|---|---|---|
Rigid Pavement | -W/C ratio
-Consolidation/density -Joint Construction |
-Air content
-Thickness -Finish/texture/skid resistance -Strength -Vibration/placement -Curing |
-Surface
smoothness to tolerance
-Slump/plasticity -Uniformity of mix -Gradation -Rebar placement/cover -Aggregate quality |
-Cement
quality
-Total time cement exposed to moisture -Mix effort -Batching/mixing inspection -Mix temperature |
Bituminous Pavement | -Compaction/density
-Asphalt content -Gradation |
-Surface smoothness/tolerance
-Thickness -Asphalt source, grade and properties -Aggregate quality -Stability -Void ratio -Skid resistance |
-Uniformity of mix
-Mix temperature -Viscosity -Ductility -Plasticity -Batching/mixing inspection |
-Longitudinal joint construction
-Use of admixtures -Bond with underlying layer -Laydown inspection |
Bridge Deck and/or Protective System Construction | -Consolidation/density
-Rebar placement/concrete cover -W/C ratio -Density (Iowa Mix) |
-Mix temperature
-Curing -Air content -Strength -Finish/texture/skid resistance -Vibration/placement -Formwork |
-Surface smoothness/tolerance
-Thickness -Slump/plasticity -Gradation -Cement quality -Batching/mixing inspection -Falsework |
-Transporting/discharging concrete
-Total time cement exposed to moisture -Aggregate quality -Mixing effort -Mix uniformity -Use of admixtures |
Structural Concrete | -Consolidation/density
-W/C ratio |
-Curing
-Strength -Air content -Rebar placement/cover -Vibration/placement -Formwork -Temperature Control |
-Slump/plasticity
-Use of admixtures -Finish -Cement quality -Aggregate quality -Gradation |
-Total time cement exposed
-Mixing effort -Batching/mixing inspection -Transporting/discharging concrete |
Base Course | -Compaction/density
-Gradation |
-Thickness
-Moisture/admixture content -Aggregate quality -Uniformity of materials -Drainage |
-Surface smoothness/tolerance
-Use of admixtures -Treatment/admixtures -Placement inspection -Strength of treated bases |
|
Embankment | -Compaction/density
-Moisture/admixture content |
-Material quality
-Uniformity of materials -Drainage |
-Stability
-Fine grade line -Placement inspection -Gradation -Soil classification -Lift thickness |
-Plasticity
-Foundation preparation -Slope rounding/shaping -Equipment type -Treatment/admixture type |