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SECTION 32 12 36.15
SECTION 32 12 36.15
MICRO-SURFACE SEAL
PART 1 GENERAL
| 1.1 | SECTION INCLUDES |
| A. | Products and procedures for mixing and spreading a properly proportioned mixture of aggregate, mineral filler, additives, polymer-modified asphalt emulsion, and water. |
| B. | Products and procedures for a cured mixture with a homogeneous appearance, a firm surface adhesion, and a skid resistant texture. |
| 1. | Provide a micro-surface mixture that is capable of being spread in variable thickness cross-sections, ruts, scratch courses, and surfaces. |
| 1.2 | REFERENCES |
| A. | AASHTO M 17: Standard Specification for Mineral Filler for Bituminous Paving Mixtures |
| B. | AASHTO M 208: Standard Specification for Cationic Emulsified Asphalt |
| C. | AASHTO T 11: Materials Finer Than 75 µm (No. 200) Sieve in Mineral Aggregate |
| D. | AASHTO T 27: Sieve Analysis of Fine and Coarse Aggregates |
| E. | AASHTO T 49: Penetration of Bituminous Materials |
| F. | AASHTO T 53: Softening Point of Bitumen |
| G. | AASHTO T 59: Testing Emulsified Asphalts |
| H. | AASHTO T 96: Resistance to Degradation of Small-Size Coarse Aggregate by Abrasion and Impact in the Los Angeles Machine |
| I. | AASHTO T 104: Soundness of Aggregate by Use of Sodium Sulfate or Magnesium Sulfate |
| J. | AASHTO T 176: Plastic Fines in Graded Aggregates and Soils by Use of the Sand Equivalent Test |
| K. | AASHTO T 278: Surface Frictional Properties Using the British Pendulum Tester |
| L. | AASHTO T 279: Accelerated Polishing of Aggregates Using the British Wheel |
| M. | AASHTO T 316: Viscosity Determination of Asphalt Binder Using Rotational Viscometer |
| N. | ASTM D 6372: Standard Practice for Design, Testing and Construction of Micro-Surfacing |
| O. | ISSA A 143 Guidelines (Current edition) |
| P. | UDOT Minimum Sampling and Testing Requirements |
| 1.3 | SUBMITTALS | |
| A. | Provide the COR with Mix Design 14 days prior to beginning construction. | |
| 1. | Meet requirements of this Section, article 2.6. | |
| B. | Provide the COR with the following for asphalt/polymer emulsion with job-mix design. | |
| 1. | Test report: Meet the requirements of this Section, article 2.1. | |
| 2. | Job-mix design. | |
| 3. | A certificate of analysis and compliance from the manufacturer for each shipment | |
| 4. | Target gradation for combined aggregate and mineral filler. | |
| 5. | Verify asphalt/polymer emulsion supplier adheres to UDOT Minimum Sampling and Testing Requirements Section 508 Asphalt Emulsion Quality Management Plan. | |
| C. | Provide test reports for mineral aggregate. | |
| 1. | Meet the requirements of this Section, article 2.2. | |
| D. | Provide verification that Hydrated Lime meets specified requirements. | |
| E. | Provide a Manufacturer’s Certificate of Compliance for Mineral Filler. | |
| F. | Provide calibration documentation for each mixing unit that includes an individual calibration for each material at various settings, which can be related to the machines metering devices. | |
| G. | To make changes in the job-mix gradation: |
| 1. | Submit a written request for a change in the job-mix gradation. | |
| 2. | Submit a new job-mix design if any changes in gradation are outside the gradation band allowed by the stockpile tolerance in Table 2. | |
PART 2 PRODUCTS
| 2.1 | EMULSIFIED ASPHALT |
| A. | Use a CSS-1h, quick-set polymer-modified asphalt emulsion conforming to AASHTO M 208; delete the cement mixing test requirements. |
| B. | Mill or blend the polymer material into the asphalt or emulsifier solution prior to the emulsification process. |
| C. | The asphalt/polymer emulsion must parallel the standard from an established infrared spectrum characterizing the asphalt/polymer emulsion. |
| D. | Modified Emulsion Residue, meet Table 1: |
Table 1: MODIFIED EMULSION RESIDUE
| TEST |
| DESCRIPTION |
| SPECIFICATION |
| AASHTO T 49 |
| Penetration, 77 |
| 40-90 |
| AASHTO T 53 |
| Softening point |
| 135 Min |
| AASHTO T 59-modified (a) |
| F Residue by distillation |
| 62% Min. |
| AASHTO T 316 |
| Rotational Viscosity 275 F |
| 650 CPS |
(a) Modified distillation procedure: Heat emulsion residue to 270 ± 10 degrees F and maintain that temperature for 20 minutes. Perform the distillation within 60 ± 15 minutes
| 2.2 | MINERAL AGGREGATE |
| A. | Use 100 percent manufactured mineral aggregates that meet the following requirements: |
| 1. | Clean and free from organic matter, clay balls, or other detrimental substances. |
| 2. | Maximum weighted sodium sulfate soundness loss of 15 percent. Refer to AASHTO T 104. |
| 3. | Maximum loss by abrasion of 30 percent. Refer to AASHTO T 96. |
| 4. | Sand equivalent of sixty or greater. Refer to AASHTO T 176. |
| 5. | Minimum polishing value of 31. Refer to AASHTO T 278 and T 279. |
| a. | Performed on aggregate prior to crushing. |
| b. | Predominantly limestone or dolomite aggregates will not be accepted. |
| B. | Select a job mix or target gradation within the gradation band. Base the mix design on this gradation. The percent passing each sieve will not vary by more than the stockpile tolerance and still remain within the gradation band after the target gradation has been submitted. Refer to AASHTO T 11, AASHTO T 27, and Table 2. |
Table 2: Job-Mix Gradation Design Limits
| Sieve Size |
| Broad Band Gradation Percent Passing |
| Stockpile Tolerances |
| 2.3 | MINERAL FILLER |
| A. | Use portland cement, hydrated lime, or aluminum sulfate as specified in AASHTO M 17 |
| 2.4 | WATER |
| A. | Use water that is potable and free from harmful salts, reactive chemicals, and any other contaminants. |
| 2.5 | ADDITIVES |
| A. | Use additives as required to accelerate or retard the break-set of the micro-surface mix, to improve the resulting finished surface, or to increase adhesion. |
| 1. | Determine the initial additive quantities from the mix design for the micro-surface mix or individual materials. |
| 2. | Use additives that are compatible with the other components of the mix. |
| 3. | Obtain COR approval for use of additives. |
| 2.6 | JOB-MIX DESIGN |
| A. | Design according to ASTM D 6372-99a. |
| 1. | Show each ingredient amount: |
| a) | Residual asphalt cement content, within 7.5 ± 2 percent by dry total weight of aggregate. |
| b) | Aggregate gradation (target) within the job-mix gradation design limits in Table 2. |
| c) | Mineral filler, percentage by total dry weight of aggregate. |
| d) | Polymer modifier 2.5 percent minimum polymer solids based on the residual asphalt content. |
| 2. | Identify additives as determined by design testing to control mix set times and adhesion. |
| a) | Provide acceptable percent limits for additives. |
| 3. | Conform to the ISSA A143 specifications listed in Table 3. |
| 4. | Use the same materials and aggregate gradation to be used on the project. |
Table 3: ISSA Specifications
| ISSA TEST NO. |
| DESCRIPTION |
| SPECIFICATION |
@ 30 Minutes Minimum (Set) @ 60 Minutes Minimum (Traffic)
12 kg-cm Minimum 20 kg-cm Minimum or Near Spin
| ISSA TB-109 |
| Excess Asphalt by LWT Sand Abrasion |
| 50 g/ft2 Maximum |
(538 g/m2 Maximum)
| ISSA TB-114 |
| Wet Stripping |
| Pass (90% Minimum) |
| *ISSA TB-100 |
| Wet-Track Abrasion Loss |
One-hour Soak Six-day Soak 50 g/ft2 (538 g/m2) Maximum 75 g/ft2 (807 g/m2) Maximum
| ISSA TB-147 |
| Lateral Displacement |
Specific Gravity after 1,000 Cycles of 125 Pounds 5% Maximum
2.10 Maximum
| ISSA TB-144 |
| Classification Compatibility |
| 11 Grade Points Minimum (AAA, BAA) |
| ISSA TB-113 |
| Mix Time @ 77 degrees F |
| Controllable to 120 Seconds Minimum |
* Perform the wet track abrasion test under laboratory conditions as a component of the mix design process.
| 2.7 | EQUIPMENT | |
| A. | Use mixing equipment specifically designed and manufactured to mix and place micro-surfacing. | |
| 1. | Mix the material by an automatically sequenced, self-propelled micro-surfacing mixing machine that will be a continuous flow mixing unit, able to accurately deliver and proportion the aggregate, emulsified asphalt, mineral filler, control setting additive, and water to a revolving multi-blade double shafted mixer and discharge the mixed product on a continuous flow basis. | |
| 2. | Use a machine with sufficient storage capacity for aggregate, emulsified asphalt, mineral filler, control additive, and water to maintain an adequate supply to the proportioning controls. | |
| 3. | Use a machine capable of self-loading materials while continuing to place micro-surfacing. | |
| 4. | Equip the machine to allow the operator to have full control of the forward and reverse speed during applications of the micro-surfacing material. | |
| a) | Use original equipment manufacturer design for the self-loading device, opposite side driver stations, and forward and reverse speed controls. | |
| 5. | Use proportioning devices with individual volume or weight controls for proportioning each material, such as aggregate, mineral filler, emulsified asphalt, additive, and water to be added to the mix. | |
| a) | Use proportioning devices with controls properly marked that calibrate and determine the material output at any time. | |
| B. | Use spreading equipment that will agitate and spread the mixture uniformly by means of twin-shafted paddles or spiral augers fixed in the spreader box. | |
| 1. | Provide a front seal that results in no loss of mixture at the road contact point. | |
| 2. | Provide an adjustable rear seal that acts as final strike-off. | |
| 3. | Use a spreader box with the rear strike-off designed and operated to produce a free flow of uniformly consistent materials to the rear strike-off. | |
| 4. | Use a spreader box with a suitable means provided to side shift the box to compensate for variations in the pavement geometry. | |
| 5. | Provide a secondary strike-off to improve surface texture and with the same adjustments as the spreader box. | |
| 6. | Use a rut filling spreader box specifically designed to fill ruts when filling ruts with an average depth greater than one-half inch. | |
| a) | Apply micro-surface as a scratch-coat pass when required to fill ruts less than ½ inch at the direction of the COR. | |
| b) | Make multiple passes with the rut filling spreader box for ruts of over ½ inch at the direction of the COR. | |
| c) | Allow a 24-hour cure time after filling ruts before placing final micro-surfacing layer. | |
| C. | Calibrate each mixing unit in the presence of the COR as follows: | |
| 1. | Prior to using on the project. |
| 2. | After repairs or as directed by the COR. | |
PART 3 EXECUTION
| 3.1 | LIMITATIONS |
| A. | Do not apply micro-surface during rain, when road surface moisture is present, or during other adverse weather conditions. |
| B. | Do not apply micro-surface if either the pavement or air temperature is below 50 degrees F. |
| C. | Do not apply micro-surface when the temperature is projected below 33 degrees F within 24 hours of placing micro-surface. |
| D. | Cease micro-surface operations when the weather or other conditions prolong opening road surface to traffic beyond two hours. |
| E. | Keep traffic off roadway surface until the micro-surface has cured. |
| 3.2 | STOCKPILE |
| A. | Construct individual 500-ton stockpiles of micro-surface aggregates. |
| 1. | COR approves stockpiles a minimum of four and a maximum of seven days prior to use. |
| B. | Provide test results for the initial stockpiles to the COR a minimum of seven calendar days prior to micro-surface placement for acceptance. |
| C. | Obtain the COR’s written acceptance of a stockpile prior to its use in micro-surface. |
| D. | Remove material not meeting specifications from the stockpile area. |
| E. | The Contractor will retest corrected material for acceptance at no additional cost to the Government. |
| 3.3 | PREPARATION |
| A. | Clean the surface of all dirt, sand, dust, oil, and other objectionable material immediately prior to applying micro-surface. |
| B. | Allow un-sealed cracks to dry thoroughly prior to applying micro-surface when using water to clean the road surface. |
| C. | Cover manholes, valve boxes, drop inlets, and other service utility entrances prior to surfacing. |
| 3.4 | APPLICATION |
| A. | Pre-wetting the surface is allowed when required by local conditions by fogging ahead of the micro-surface box. |
| 1. | Do not over apply causing free water to sit on the pavement in front of the micro-surface box. |
| B. | Place micro-surface mix that meets the job-mix design. |
| 1. | Control the ingredients proportions by metering or measuring devices on the micro-surfacing equipment. |
| a. | Use readings from the metering or measuring devices to determine compliance with limits stated in the approved job-mix design. |
| 2. | Limit any increase or decrease in the amount of mineral filler added to the mix during production to 1 percent of the job-mix design. |
| 3. | The emulsion submitted with the job-mix design will serve as the standard to assure the same emulsion is used throughout the project. |
| a. | COR may request a new job-mix design and re-approval of the micro-surfacing if large disparities occur. |
| C. | Pass the mineral aggregate over a scalping screen prior to transfer to the micro-surfacing mixing machine to remove oversize material. |
| D. | Carry a sufficient amount of micro-surface in all parts of the spreader so that full width and complete coverage is obtained with no streaks or narrow spots. |
| 1. | Avoid overloading the spreader. |
| E. | Apply micro-surface of proper consistency at an average rate of 24 to 30 lb/yd2. |
| 1. | Apply micro-surface for rut filling as required. |
| F. | Do not add additional water for any reason once the mixture has been placed onto the road surface. |
| G. | Remove and replace the micro-surface if any of the following occurs: |
| 1. | Lumping, balling, or unmixed aggregates. |
| 2. | Separation of the coarse aggregate from the emulsion and fines. |
| 3. | Excessive breaking of emulsion inside the spreader box. |
| 4. | Streaking caused by oversized aggregate. |
| 5. | Flushing or excessively rich areas appearing in the micro-surfacing after two hours from the time of placement. |
| 6. | Any measurable rutting, shoving, or other evidence of premature deformation when exposed to traffic with re-approved micro-surfacing materials and procedures. |
| 3.5 | TEST STRIP |
| A. | Apply a test strip of at least 500 ft in length on the roadway before initial placement commences. |
| 1. | Achieve initial set within 30 minutes and show no visual signs of distress when exposed to traffic action after curing for 2 hours. |
| 2. | Become part of the completed item if the above conditions are present and all other requirements are met. |
| 3. | Remove and replace the micro-surfacing at no expense to the Government if the test strip fails to meet the conditions stated above. |
| B. | Make necessary adjustments if test strip does not pass. |
| 1. | Obtain approval from the COR prior to repeating the test strip process. |
| 2. | The COR may require a new job-mix design if failures indicate an ingredient problem. |
| 3.6 | FINISHING DETAILS | |
| A. | Place the micro-surface so the depth of each course does not exceed twice the maximum aggregate size. | |
| B. | Do not create build-up when constructing longitudinal and transverse joints. | |
| C. | Place micro-surface adjacent to concrete pavements or concrete curb and gutter with a straight longitudinal edge. | |
| 1. | Do not allow over-lap in these areas. | |
| D. | Maintain straight lines at all locations. | |
| E. | Place micro-surface at side streets and intersections out to right-of-way line. | |
| F. | Use hand squeegees to spread micro-surface in areas that cannot be reached with micro-surface machine. | |
| 1. | Lightly dampen areas prior to mix placement. |
| 2. | Provide complete and uniform coverage. |
| 3. | Avoid unsightly appearance from handwork. |
| 4. | Use the same type of finish in hand worked areas as applied by the spreader box. | |
| G. | Use construction paper or comparable products so all beginning and ending joint lines from each construction pass are straight. | |
END OF SECTION
MICRO-SURFACE SEAL Page 1
