Earthwork (Grading, Excavation and Filling, Foundations)

 

Asphaltic Concrete

 

Reinforcing Steel

 

Concrete Batch Plant

 

Concrete

 

Shotcrete

 

Pre-Tensioned Concrete

 

Post-Tensioned Concrete

 

Masonry

 

Structural Steel and

 

High Strength Bolting

 

Nondestructive Testing

 

Spray-Applied Fireproofing

 

Glu Lam and Truss Joists

 

Shear Walls and Floor Systems Used as Shear Diaphragms

SECTION 2 - ASPHALTIC CONCRETE

OBJECTIVE

The performance of asphaltic concrete pavement is as much affected by the careful construction of the subgrade and base, as it is by the control of the asphaltic concrete itself. Therefore, the paving inspector must be knowledgeable in soils as well. The purpose of observation and testing of asphaltic concrete paving is to verify that the paving contractor and his supplier are exercising adequate quality control in their operations and are providing a finished product that complies with the project plans and specification requirements.

This objective can best be achieved by qualified special inspectors performing the following duties under the direct supervision of the materials engineering laboratory.

OBSERVATION DUTIES

A. Documents

1. Review the approved plans and specifications, and meet with contractor and suppliers before construction to discuss project and to verify that requirements for testing and observation are well understood.
2. Review material certificates and test reports for compliance with job specifications.
3. Prepare or review mix designs for compliance to project requirements.

B. Sampling of Materials

1. Sample and perform preliminary tests on proposed aggregates and asphalt cement (gradation, soundness, abrasion, stripping, etc.)

C. Subgrade and Base

1. Confirm that sources of materials have been sampled and approved.
2. Verify that materials delivered are of uniform quality.
3. Verify that control testing of subgrade materials is being performed and recorded as required.
4. Verify that subbase and bases courses are of the source, type, thickness and density specified.
5. Verify that soil sterilization is provided, if required.
6. Refer to Section 1, Earthwork for additional details.

D. Batch Plant

1. The special inspector should become familiar with the appearance and physical characteristics of the mix to be used by observing visually the finished mixture so that unsatisfactory conditions may be readily recognized.
2. Check the batch plant facilities prior to production of asphaltic concrete mixture.
3. Check aggregates in stockpile to verify conformance to materials utilized in the design.
4. Check the bin weights of the aggregate fractions and asphaltic cement (batch plant only).
5. Check the temperature of the mixed batches on the truck.
6. Perform hot-bin gradations of the blended aggregates (where applicable).
7. Verify cold-bin feeds and hot-bin batch weights are adjusted as necessary to produce the job-mix formula within tolerance.
8. Before loading, truck beds should be checked for cleanliness and absence of materials that might be detrimental to the mix.
9. Coordinate with the job site inspector to obtain a uniform and consistent asphaltic concrete mixture.

E. Spreading and Paving

1. The field inspector should contact the batch plant inspector promptly should conditions be observed during placement and spreading operations that suggest a need for change at the plant. The following items should be addressed prior to and during placement operations:
   1. Area to be paved, cleaned and properly primed, or tack coated.
   2. Leveling course installed where required.
   3. Suitability of spreading and paving equipment.
   4. Asphalt mix temperature when delivered, and after final rolling, is within limits required.
   5. Density tests by nuclear gauge during rolling.
   6. Thickness control by adequate placement and compaction.
   7. Sampling of asphaltic concrete at jobsite during placement for laboratory testing (extraction, gradation, stability, etc.)
   8. Core samples taken for verification of thickness and density of in-place asphaltic concrete.
   9. Application of seal coat and curing in accordance with specification requirements, if required.

F. Verification Tests

1. Stability and density, bulk specific gravity, and maximum specific gravity.
2. Asphalt content by extraction.
3. Aggregate gradation of the mixture from extracted sample.
4. Physical properties of the asphalt cement: Penetration, viscosity, ductility, and specific gravity.
5. Aggregate quality: Los Angeles abrasion, liquid limits of soils and plastic limit and plasticity index, and sieve analysis.
6. Field density.
7. Thickness determination.
8. Smoothness tolerance.

G. Reports

1. Submit written progress reports describing the tests made and showing the action taken to correct nonconforming work. Itemize any changes authorized by architect engineer. Report all uncorrected deviations from plans of specifications.

 

 

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