Category:402 Bituminous Surface Leveling

From Engineering_Policy_Guide
Revision as of 08:11, 8 June 2007 by Tschid (talk | contribs)
Jump to navigation Jump to search

402.1 Construction Inspection for Sec 402

This is not a contract document and is to be used solely as a commentary on Standard Specification Section 402. Surface leveling mixes will be referred to as SL throughout this section. SL mixes are used to correct any irregularities in the surface of an existing pavement on a route with low traffic volumes.

402.1.2 Material (Sec 402.2)

Reclaimed Asphalt Pavement (Sec 402.2.3)

See Reclaimed Asphalt Pavement (RAP) in Plant Inspection.

402.1.3 Composition of Mixture (Sec 402.3)

Gradation of Combined Aggregates (Sec 402.3.1)

The aggregate sources used in the mix must be the same as those required by the JMF. The combined aggregate shall meet the gradation required in Standard Specification Section 402.3.1.

Alternate Gradation (Sec 402.3.2)

If wet bottom boiler slag is used to replace coarse aggregate, the combined aggregate shall meet the gradation required in Standard Specification Section 402.3.2.

Reclaimed Asphalt Pavement Sec 402.3.3)

See Reclaimed Asphalt Pavement (RAP) in Plant Inspection.

402.1.4 Job Mix Formula (Sec 402.4)

The requirements of Standard Specification Section 401.4 apply.

402.1.5 Gradation Control (Sec 402.5)

The inspector should perform a sieve analysis on the hot bins or the combined cold feed at a minimum of once per day. Testing may be waived, with the RE’s approval and the contractor’s certification of the mix, when less than 200 tons are produced per day. The combined aggregate gradation must be within the master range specified in Standard Specification Section 402.3.1 at all times. The combined aggregate gradation can vary from the JMF by the maximum tolerance shown in the table below. The mix shall be produced at the binder content shown on the JMF. However, the binder content of the mix, as determined by calculations or sampling and testing, must be within the following maximum tolerance from the JMF.

Property Tolerance
#200 ±2.0%
Binder Content ±0.5%

The Standard Specifications do not put testing requirements on the binder content. However, if there is any reason to suspect that the binder content of the mix is not within these specifications, the inspector should take a sample and determine the binder content of the mix. For example, a sample should be taken and tested if the mix appears too dry or too wet. The binder content, as shown on the JMF, cannot be changed during production without written approval from Construction and Materials, even if the resulting binder content is within the tolerance from the JMF. If a new binder content is approved, the tolerance will apply to the new target. If a sieve analysis indicates a deviation from the JMF exceeding the specified tolerances, the contractor will be notified immediately. The contractor shall then review the cold feed settings and make any necessary adjustments. As soon as any adjustments are completed, another test will be performed. If excessive deviation still exists, the contractor will be informed and production shall stop. Further adjustments or revisions shall be made until an acceptable sieve analysis is obtained. At this time, production can resume. Adjustments in the cold feed percentages in excess of 5.0% may require a new JMF.

402.1.6 Sample Location (Sec 402.6)

See "Reclaimed Asphalt Pavement (RAP)" and "Sieve Analysis" in Plant Inspection. When sampling for the binder content of the mix, see also "Asphalt Binder Content."

402.1.7 Moisture Content (Sec 402.7)

See Asphalt Binder Content. When sampling for the binder content, also determine the moisture content of the mix.

402.1.8 Contamination (Sec 402.8

See Material Acceptance.

402.1.9 Field Laboratory (Sec 402.9)

See Field Laboratory.

402.1.10 Construction Requirements (Sec 402.10)

Weather Limitations (Sec 402.10.1)

See Weather Conditions. SL mixes shall not be placed if the ambient air temperature or the existing surface temperature is below 50°F.

Bituminous Mixing Plants (Sec 402.10.2)

See Bituminous Mixing Plants.

Subgrade Preparation (Sec 402.10.3) In this case, subgrade refers to the existing pavement. Before the project begins, District Maintenance should perform any necessary repairs that may not be compensated for by the surface leveling. Deep rutting or dips should be filled prior to the placement of the surface leveling unless otherwise directed by the District Operations Engineer. The existing pavement surface should be cleaned and tacked in accordance with Standard Specification Section 407.

Hauling Equipment (Sec 402.10.4)

See Haul Trucks.

Spreading (Sec 402.10.5)

See Spreading and Hand Spreading in Paving Operations.

Irregularities (Sec 402.10.5.1)

See Spreading in Paving Operations.

Joints (Sec 402.10.6)

See Transverse Joints and Longitudinal Joints in Paving Operations.

Compaction (Sec 402.10.7)

See Rollers in Paving Equipment and Compaction in Paving Equipment. At least 3 passes shall be made over the entire mat with either a pneumatic tire roller or a steel wheel roller. The steel wheel roller may be a static or vibratory roller. SL mixes are generally placed very thin (minimum of 1 in.). Therefore, the reaction of the mat to compaction must be watched very closely. The inspector should ensure that the roller(s) used for compaction weigh at least 10 tons. A steel wheel roller, or a vibratory roller operated in static mode, must be used for final rolling.

Surface Condition (Sec 402.10.8)

See Material Acceptance.

402.1.11 Method of Measurement

The total tonnage accepted will be measured to the nearest 0.1 ton.

402.1.12 Basis of Payment

The accepted quantity of SL mix will be paid for at the contract unit price. The contract unit price is set up as total mix (mineral aggregate and asphalt binder are no longer paid for separately).

402.2 Materials Inspection

402.2.1 Scope

To establish procedures for mix design of plant mix bituminous surface leveling. Ingredients for use in plant mix bituminous surface leveling are to be inspected in accordance with the applicable guidelines. Trial mix aggregate samples shall be submitted in accordance with Field Sec 1001 of the Materials Manual. Plant calibrations, if requested, shall be performed in accordance with General Section 10 in the Materials Manual.

402.2.2 Procedure

Mix design procedures are identical to those shown in Materials Inspection in Asphaltic Concrete Pavement. If it becomes necessary to calculate a mix, the formulae, procedure and reporting shall be performed as described in Laboratory Sec 403 of the Materials Manual.