Category:402 Bituminous Surface Leveling
402.1 Construction Inspection
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. 402.2 Material. 402.2.3 Reclaimed Asphalt Pavement. See also GCM Section 400.4.11 “Reclaimed Asphalt Pavement (RAP).” on page 9. 402.3 Composition of Mixture. 402.3.1 Gradation of Combined Aggregates. 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. 402.3.2 Alternate Gradation. 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. 402.3.3 Reclaimed Asphalt Pavement. See also GCM Section 400.4.11 “Reclaimed Asphalt Pavement (RAP).” on page 9. 402.4 Job Mix Formula. The requirements of Standard Specification Section 401.4 apply. 402.5 Gradation Control. 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 sieve ±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.
402.6 Sample Location. See also GCM Sections 400.4.11 “Reclaimed Asphalt Pavement (RAP).” on page 9 and 400.4.15 “Sieve Analysis.” on page 14. When sampling for the binder content of the mix, see also GCM Section 400.4.14 “Asphalt Binder Content.” on page 12. 402.7 Moisture Content. See also GCM Section 400.4.14 “Asphalt Binder Content.” on page 12. When sampling for the binder content, also determine the moisture content of the mix. 402.8 Contamination. See also GCM Section 400.7.6 “Material Acceptance.” on page 30. 402.9 Field Laboratory. See also GCM Section 400.4.7 “Field Laboratory.” on page 8. 402.10 Construction Requirements. 402.10.1 Weather Limitations. See also GCM Section 400.7.3 “Weather Conditions.” on page 25. SL mixes shall not be placed if the ambient air temperature or the existing surface temperature is below 50°F. 402.10.2 Bituminous Mixing Plants. See also “GCM Section 404” on page 73. 402.10.3 Subgrade Preparation. 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. 402.10.4 Hauling Equipment. See also GCM Section 400.5.2 “Haul Trucks.” on page 18. 402.10.5 Spreading. See also GCM Section 400.7.4 “Spreading.” on page 26 and 400.7.5 “Hand Spreading.” on page 30. 402.10.5.1 Irregularities. See also GCM Section 400.7.4 “Spreading.” on page 26. 402.10.5.2 Edge Differential. 402.10.6 Joints. See also GCM Sections 400.7.8 “Transverse Joints.” on page 33 and 400.7.9 “Longitudinal Joints.” on page 33. 402.10.7 Compaction. See also GCM Sections 400.5.5 “Rollers.” on page 22 and 400.7.7 “Compaction.” on page 31. 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. 402.10.8 Surface Condition. See also GCM Section 400.7.6 “Material Acceptance.” on page 30. 402.10.9 Hauling Over Completed Surface. 402.11 Method of Measurement. The total tonnage accepted will be measured to the nearest 0.1 ton. 402.12 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).