Prior to placing any pavement, manhole frames and covers, valve boxes, and other such utility access structures shall be adjusted in elevation by the Contractor if needed to match the surface of the new pavement. For overlaying existing pavement, cast iron or ductile iron extensions rated for not less than H-20 loading shall be used and shall meet the approval of the City of Magnolia, Engineer or the designated representative of the Engineer. The Contractor shall adjust the height of manhole frames and covers, valve boxes, and other such utility access in a manner acceptable to the Engineer or the designated representative of the Engineer to the grades required for the new pavement placed on either a base course or an existing asphalt course.
The base course or asphalt course to be overlayed shall be cleaned by sweeping or other methods approved by the Engineer or designated representative of the Engineer. The base course shall be lightly sprinkled immediately before the prime coat is applied. All rate of application and pressure gauges will be inspected and calibrated prior to applying the prime or tack coat. MC-30 prime coat shall be applied at a rate of 0.30 gallons per square yard at a temperature between 70° and 150° Fahrenheit. The prime coat shall be allowed to dry for a period of forty-eighty (48) hours or shall be allowed to dry longer if required by conditions in the opinion of the Engineer or the designated representative of the Engineer. RC-250 tack coat
shall be applied at a rate of 0.10 gallons per square yard at a temperature between 70° and 150° Fahrenheit. The prime and tack coats will be applied in strict accordance with the requirements of Item 310 of the Texas Department of Transportation Standard Specifications for Construction of Highways, Streets and Bridges.
(Ordinance 2007-106, App. B, adopted 3/20/07)
A. 
Laying.
1. 
The asphaltic concrete mixture shall be hauled to the worksite in vehicles cleaned of all foreign materials and, if required by the Engineer or the designated representative of the Engineer, covered with a canvas that is sufficient to protect the entire load. The vehicle dispatching the material shall be arranged so that all material delivered may be placed and initially rolled in the daylight. The mixture shall be deposited directly into the “lay down” machine or placed on the prepared base in windrows that will be spread to the line, grade and crown as specified on the plans. Transfer of mixture from dispatching vehicle to “lay down” machine using front-end loaders or other equipment shall not be allowed unless specifically approved by the Engineer or the designated representative of the Engineer. The mixture shall be spread without segregation or tearing. The mixture must be at a temperature between 200 degrees and 350 degrees Fahrenheit.
2. 
The base, or initial, course of asphaltic concrete mixture shall be spread in one (1) lift so that when compacted, the finished course will be smooth, of uniform density, and will be to section, line and grades as shown on the plans.
3. 
A surface course of two (2) inches or less in thickness may be spread in one (1) lift. All lifts shall be spread such that when compacted, the finished course will be smooth, of uniform density, and will be to section, line and grades as shown on the plans.
4. 
Asphalt base and surface courses may be spread and finished by hand if use of paving equipment is impractical. Steel or wood forms, rigidly supported to assure correct grade and cross-section, shall be used. Place the materials carefully in order to avoid segregation of the mix. Broadcasting of the material shall not be permitted. Any lumps that do not break down must be removed. Asphalt courses must be put down in the same sequence as if placed by machine.
B. 
Rolling.
Rolling equipment shall consist of pneumatic tire and steel wheel rollers.
1. 
Pneumatic tire rollers shall have equal size and diameter pneumatic tires that are capable of exerting a contact pressure varying from 40 to 110 psi by adjusting ballast and/or tire pressure. Wheel spacing will be such that one (1) pass will accomplish one (1) complete coverage equal to the width of the roller and have a 1/4-inch (1/4") minimum overlap. None of the wheels shall wobble. The tire pressure and operating weight shall be sufficient to achieve the desired density. The roller shall be self-propelled.
2. 
Steel wheel rollers shall be a three (3) wheel roller two-axle tandem roller or three-axle tandem roller weighing not less than eight (8) tons and capable of developing a compression in the rear wheels of 250 to 350 pounds per inch of roller width. The rollers shall have power units and be equipped with the means of keeping the wheel wet to prevent the mixes from sticking to the rollers. The rollers shall also be equipped with wheel scrapers to assist in keeping the wheels clean.
3. 
Rolling shall start at the sides longitudinally and proceed toward the center of the pavement, overlapping on successive trips by at least 1/2 of the width of the rear wheels. Alternate trips of the roller shall be slightly different in length. Continue rolling until no further compression can be obtained and all roller marks are eliminated. The roller motion shall be slow enough to insure no displacement of the hot mixture. The roller must not sit on completed pavement that has not cooled to the normal atmospheric temperature. The wheels shall be properly moistened with water to prevent the hot mixture from sticking to the rollers, but an excess of water shall not be permitted.
4. 
If the asphalt is not being compacted properly, in the opinion of the Engineer or the designated representative of the Engineer, then cores will be taken and tested in order to determine the relative densities of the course at various locations.
5. 
The completed course shall have a uniform density over the entire roadway area. The Engineer or the designated representative of the Engineer may, after testing under acceptable practices, have all or parts of the course removed and replaced on areas where the density is found to vary. The task of removing and replacing of the course because of unacceptable density variations shall be completed at the cost of the Contractor.
C. 
Hand Tamping.
In areas where compaction by a roller is not easily accomplished, such as along walls, curbs, headers, etc., a vibrating plate compactor or lightly oiled tamps shall be used to thoroughly compact the mixture in three-inch (3") layers.
D. 
Density.
The base course, binder course and surface course shall be compacted to a minimum density of 95 percent (95%) of the maximum possible density of a voidless mixture composed of the same materials in like proportions. If the results of the density tests for the base course, binder course or surface course indicate that the minimum density of 95 percent (95%) has not been obtained, additional rolling with a three-wheel or pneumatic roller will be required before the mix cools.
E. 
Surface Requirements.
The finished surface of plane areas shall not vary more than 1/4-inch (1/4") from a 16-foot (16') straightedge applied to the surface. The straightedge must overlap the previous test by 1/4 of its length. Any irregularities which vary more than 3/16 -inch (3/16") in 10-feet (10') or 1/4-inch (1/4") in 16-feet in accordance with the grade, valley and crown shown on the plans shall be corrected.
F. 
Construction Joints.
Each course shall be placed as nearly continuous as possible. The roller shall only pass over the unprotected end of the freshly laid mixture when the laying of the course is discontinued for such a length of time as to allow for the mixture to become chilled. In such cases, when the work is resumed, the material laid shall be either cut back in order to obtain a beveled edge for the full thickness of the course or an acceptable lap joint shall be made.
G. 
No portion of the finished asphalt course shall be opened to traffic until 12-hours after rolling has been completed, except where shown on the plans or in an emergency.
(Ordinance 2007-106, App. B, adopted 3/20/07)
Pavement sections not meeting the specified densities shall be recompacted or replaced with new asphaltic concrete material. Pavement not having an acceptable surface course texture, not meeting surface test requirements, or not meeting the minimum thickness shall be replaced with new material sections of surface course.
(Ordinance 2007-106, App. B, adopted 3/20/07)
A. 
Extraction Test.
The percentage of bitumen in any mixture shall not vary more than 1/2 of one percent (1%) from the proportion established by the Engineer or the designated representative of the Engineer. Samples of the hot mixture may be taken from the trucks or from the finished pavement, when required by the Engineer or the designated representative of the Engineer. The minimum weight of the test specimen in grams shall be determined by multiplying 3,000 by the maximum size aggregate in inches; and when tested by standard laboratory methods (in which benzol may be used as the solvent), it shall not vary from the grading proportions specified, according to the mix being tested, by more than five percent (5%) in any particular case.
B. 
Cores may be taken from the finished hot-mix asphalt concrete. The quality and thickness of the cores will govern the acceptance of the pavement.
(Ordinance 2007-106, App. B, adopted 3/20/07)