606 - MICROSURFACING 600-44
606.1 Description
Spread a mixture of modified emulsified asphalt, mineral aggregate, water and additives on a prepared surface as specified in the Contract Documents. BID ITEMS UNITS Aggregate for Microsurfacing Ton Emulsified Asphalt (*) (Modified) Ton Mineral Filler Ton *Designated Type and Grade
606.2 Materials
Provide materials that comply with the applicable requirements. Emulsified Asphalt ................................................................................................ DIVISION 1200 Aggregate for Mi crosurfacing ............................................................................... DIVISION 1100 Water ..................................................................................................................... DIVISION 2400 Conduct aggregate acceptance te sts at the point of usage. Use a Cationic Type CSS-1HM emul sified asphalt complying with SECTION 1202. For mineral filler, use any recognized brand of non-air-entrained portland cement that is free of lumps and acceptable to the Engineer. Provide a Type "C" certification for any proposed additives. The Engineer will test materials according to th e Contract Documents an d Appendix B-Sampling and Testing Frequency Chart-Quality Control/Quality Assurance Specifications.
606.3 Construction Requirements
a. Mix Design.
1.Job Mix Formula. Develop and submit the job mix formula and certified test results meeting the criteria in TABLE 606-1 for the Engineer’s approval. Include aggregate type and gradation, percentage of modified emulsion, water and cement by weight of dry aggregate in the mix. TABLE 606-1: MICROSURFACING MIX DESIGN REQUIREMENTS Property Test Requirements Wear Loss (Wet Track Test) ASTM D6372 (1 hr soak) (6 day soak) 50 g/ft2, maximum 75 g/ft2, maximum Wet Cohesion ASTM D6372 @ 30 minutes @ 60 minutes 10 in-lbs, minimum 17 in-lbs, minimum Wet Stripping ISSA TB-114 90%, minimum Mix Time @ 77oF ISSA TB-113 Controllable to 120 seconds, minimum
2.Proportioning. Use the proportions in TABLE 606-2 unless otherwise shown in the Contract Documents. Do not begin microsurfacing until the Engineer approves the mix design, materials, and construction. 606 - MICROSURFACING 600-45 TABLE 606-2: MICROSURFACING MIX PROPORTIONING Material Units Value Mineral Aggregate lbs/SY dry weight 15, minimum Modified Emulsion Percent residue by weight 6.5, minimum Mineral Filler Percent by weight of dry aggregate 1.0 to 3.0 * Additive Percent by weight of dry aggregate As required * Unless otherwise approved by the Engineer.
3.Aggregate and Asphalt. Screen the aggregate for lumps, and weigh it before delivery to the lay down machine. Weigh the emulsified asphalt. The Engineer will approve the screens and scales. Provide individual volume or weight controls for proportioning each item to be added to the mix. Calibrate and mark each material control device. Locate the devices to be accessible for ready calibration, and place so the Engineer can determine the amount of each material used at any time. Mineral filler may be added at the loading facility, provided the Engineer approves accurate proportioning and metering devices, and there is no detrimental effect on the final product. b. Surface Preparation. Immediately before applying the micros urfacing, thoroughly clean the surface of the roadway of all foreign material and pre-wet as required. c. Ruts. When shown in the Contract Documents, fill ruts, utility cuts and depressions in the existing surface before placing the final surface. Cover ruts and irre gularities of less than ½ inch in depth with a full width scratch coat. Accomplish the scratch coat by using a rigid rear seal in the spreading equipment. Independently fill ruts greater than ½ inch in depth using a rut filling spreader box 5 to 6 feet in width. Crown ruts filled with a rut filling spreader box to compensate for compaction. Ruts in excess of 1 ½ inches require multiple passes with the spreader box to restore the original cross section. When multiple passes are required, carry traffic overnight on each rut-filling pass before a subsequent filling pass is made. d. Mixing and Spreading. Mix and spread the microsurfacing materials with a self-propelled machine capable of accurately delivering and proportioning all of the required components. Operate the machine continuously while loading, eliminating construction joints. Do not use lumping, balling or unmixed aggregate. Place longitudinal joints on lane lin es. Do not overlap or leave gaps in longitudinal joints. Construct a finished microsurface with a uniform te xture and free of scratches, tears and other surface irregularities. Repair the surface if any of these conditions exist: more than 1 surface irregularity that is ¼ inch or wider and 10 feet or longer in any 100 foot section of the microsurface; more than 3 surface irregularities that are ½ inch or wider and more th an 6 inches long in any 100 foot section of the microsurface; or any surface irregularity that is 1 inch or wider and more than 4 inches long. Construct finished, uniform, longitudinal and transverse joints in the micros urface. Repair the joints if any of these conditions exist: build-up of microsurface material at the joints; uncovered areas at the joints; longitudinal joints with more than ½ inch vertical space betwee n the surface and a 4 foot straightedge placed perpendicular to the joint; or transverse joints with more than ¼ inch vertical space between the surface and a 4 foot straightedge placed perpendicular to the joint. Construct the edges of the microsurface to follow the cent erline, lane lines, shoulder lines and curb lines. Repair edges that vary more than ± 3 inches from a 100 foot straight line (or a 100 foot arch on a curved section). Use methods approved by the Engineer to correct deficiencies in the microsurface. Construct a dense, repaired surface with a uniform texture. 606 - MICROSURFACING 600-46 e. Curing. Provide adequate means to protect the microsur face from damage by traffic until the mixture has cured sufficiently. Allow the surface of microsurfacing to cure so as to not adhere to or be picked up by the tires of vehicles. Allow traffic to use the microsurfacing when cured. Cure the material used for filling wheel ruts a minimum of 24 hours before the full width coverage is applied. f. Maintenance of Traffic. Maintain traffic according to DIVISION 800 and the following: Station 1 flagger immediately ahead of the application of the microsurfacing material and 1 flagger immediately behind the section being cured. Display suitable speed limit signs and “fresh oil” sign s. Move the signs forward with the flaggers as the work progresses. Suspend application of the microsu rface early enough each day to permit traffic to safely travel over the completed work before sunset. Repair any traffic damage to the microsurface at Contractor expense. g. Seasonal and Weather Limitations. Construct the microsurfacing between May 1 and October 15. Do not place microsurfacing when the ambi ent air temperature is less than 50ºF, or the weather is foggy or raining, and the air temperature is forecasted to go below 32ºF within 24 hours following the placement. h. Observation Period. The Engineer, along with th e Contractor, will inspect the microsurfacing 30 days after work is completed on the microsurfacing. Repair ar eas where there is no cover material left in place (bare areas) as directed by the Engineer: In 5% the wheel paths; and Individual areas ≥ 10 square yards; and Where the total square yards of bare areas is greater than 5% of the total square yards of the seal. g. Pavement Smoothness. Microsurfacing is excluded from profilograph testing, and not eligible for pay adjustments.
606.4 Measurement and Payment
The Engineer will measure aggregate for microsurfaci ng, emulsified asphalt (modified) and mineral filler by the ton. No deduction will be made for moisture in th e aggregate. When sacked portland cement is used, 1 sack equals 94 pounds. Water used for pre-wetting the pavement surface and mix water is subsidiary to other bid items and will not be measured for separate payment. Material used to correct surface deficiencies in the microsurfacing will not be measured for payment. Payment for "Aggregate for Microsurfacing", "Emulsif ied Asphalt (Modified)" and "Mineral Filler" at the contract unit prices is full compensation for the specified work.
Microsurfacing in other states
Get an email when 606 changes
Kansas revises spec sections through supplementals and new editions. We check this one every week and email you the day it changes. Free, no account.
Source: Standard Specifications for State Road and Bridge Construction, 2015 Edition. Pages 281–283 of 978. View official source ↗