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185 SECTION 405 CHIP SEALS 405.1 -DESCRIPTION : This work shall consist of the construction of a wearing course, composed of asphalt emulsion immediately followed by a single layer of aggregate, in one or more applications, followed by a fog seal. The type of Chip Seal will be indicated on the Plans. The contractor shall notify the Engineer a minimum of two weeks p rior to starting any Chip Seal operation. In addition, the contractor shall submit proposed sources of all materials. 405.2 -MATERIALS : 405.2.1 -Aggregate: The aggregate shall be from a Division approved source and sha ll conform to the requirements of the Section 703.1 -4. The aggregate shall be washed to reduce dust content. The aggregates shall be crushed with a minimum of 80% two face fracture. Aggregates shall meet the gradation requirements of Table 405.2.1: TABLE 405.2.1 Aggregate Gradation Requirements for Chip Seal Sieve Size Type A Type B Type C Nominal Maximum Size No. 67 No. 8 No. 9 1 in (25 mm) 100 – – 3/4 in (19 mm) 90-100 100 – 1/2 in (12.5 mm) 100 – 3/8 in (9.5 mm) 20-55 85-100 100 No. 4 (4.75 mm) 0-10 10-30 85-100 No. 8 (2.36 mm) 0-5 0-10 10-40 No. 16 (1.18mm) – 0-10 No. 30 (600 µm) – – No 50 (300 µm) – – 0-5 No. 200 (75 µm) 0-2 0-2 0-2 405.2.2 -Asphalt Emulsion: The asphalt emulsion for Chip Seals and the emulsion for the fog seal shall be from a Division approved source and shall meet the requirements of AASHTO M 316, Table 1. Other asphalt emulsions may be used with testing and approval prior to construction. Testing shall be done a minimum of two weeks prior to the pro jected start date and follow the process outlined in Materials Procedure 401.02.25 Certification of Asphalt and Tar Shipping Terminals. 405.2.3 -Application Rate Design: The contractor shall perform a Chip Seal Design according to AASHTO PP 82 and submit to the Engineer at least one week prior to starting work. 186 405.3 -WEATHER RESTRICTIONS : Chip Seal shall be constructed only when the condition of the existing surface is satisfactory to the Engineer, when the ambient and existing pavement temperature is 50°F or above and rising, and when rain is not forecast for the next 12 hours. Surface shall be dry to damp. The temperature may be waived but only when approved by the Engineer. No Chip Sea l shall be performed between October 1 and May 1. Chip Seal operations shall be suspended immediately when rain begins or when the Engineer determines that a rain event is imminent. 405.4 -EQUIPMENT : Equipment shall inc lude equipment for emulsion distribution, aggregate spreading, compaction, and sweeping before and after application. Equipment shall also include scrapers, hand brooms, shovels, and other items as may be necessary to thoroughly clean the existing surface . 405.4.1 -Emulsion Distributor: The distributor shall be so designed, equipped, maintained and operated that asphalt material may be applied uniformly on variable widths up to sixteen ( 16) feet at readily determined and controlled rates from 0.05 to 2. 0 gal. per sq. yd. with uniform pressure and with an allowable variation from any specified rate not to exceed 0.015 gal. per sq. yd. The distributor shall also have a cab -metering system that will automatically adjust the flow of the asphalt material as the speed of the truck changes and allow the operator to adjust the rate of application from the cab of the truck. Distributor equipment shall include a tachometer, pressure gages, and a thermometer for measuring temperatures of tank contents. Distr ibutors shall be equipped with a power unit for the pump, and full circulation spray bars adjustable laterally and vertically. A manifold connection shall be provided and hand spraying equipment shall be available to cover areas and patches inaccessible to the distributor. Nozzle angles shall be positioned at an angle of 15° -30° from the horizontal of the spray bar. Application shall achieve a triple overlapping spray pattern. Verification of distributor truck calibration within the past 12 months sh all be available on the project site, preferably located within the cab of the truck. Equipment shall be calibrated according to AASHTO guide specification or manufacturers recommendations. 405.4.2 -Aggregate Spreader: The aggregate spreader shall be self-propelled with front discharge capable of adjusting to evenly and accurately distribute at the required placement rates. Aggregate spreader calibration according to ASTM D5624 shall be performed prior to starting work. Check the veil throughout the process. Recalibrate after any maintenance, repairs, or modifications that could affect spread rate. 405.4.3 -Compaction Equipment: A minimum of three self -propelled pneumatic tire rollers shall be used, at a minimum of 6 tons each. Roller tires sha ll have a minimum pressure of 80 psi. 405.4.4 -Sweepers: Power sweepers, pickup sweepers, or rotary brooms shall be used for surface preparation as well as removing any loose aggregate after compaction. Steel bristles shall not be used on the Chip Seal after compaction. 405.5 -PREPARING AND REPAIRING EXISTING SURFACE : No chip seal shall be applied until breaks, holes, depressions, and other irregularities in the existing surface have been repaired and cured sufficiently to permit the asphalt material to be placed in a uniform application. Patching and leveling material shall be plant mixed. Hand patching will be permitted where necessary. Remove all existing thermoplastic marki ngs and raised pavement markers. Protect any drains or other utility covers. Apply a light fog seal to asphalt patched surfaces less than 2 months old, using an asphalt emulsion that is compatible with the emulsion being used for the chip seal. 405.6 -CLEANING AND SWEEPING : Within 30 minutes prior to construction, the existing surface shall be swept and thoroughly cleaned to remove all mud, dirt, dust, vegetation, and other caked or loose foreign material. Cleaning shall be done to a minimum width of one foot on each side beyond the width of the surface to be placed excluding the shoulder. Materials collected in the cleaning operation shall be removed and disposed of as directed. 405.7 -APPLICATION OF ASPHALT MATERIAL : After the existing surface has been cleaned, and is in a dry condition, the asphalt material shall be applied by means of a pressure distributor. The spray bar shall be raised to a sufficient height so as to uniformly and completely coat the entire surface. The rate of application of asphalt material shall be in accordance with section 405.12, or as modified by the plans. Application temperatures of the asphalt material shall b e within the range specified in Subsection 705 for the particular material being used, or as documented by the manufacturer. Application rate shall be taken from the design. Except when required to maintain traffic, Chip Seal operations shall be done upo n the full width of the section. After application, asphalt material shall completely and uniformly cover the underlying pavement and be free of streaks, voids, and puddles. 405.8 -APPLICATION OF AGGREGATE : Immediately following each application of asphalt material, aggregate at the rate or rates called for in subsection 405.12 shall be spread with the spreader in such a manner that the entire area being treated is uniformly covered. No traffic, constructi on or otherwise, shall be allowed on the asphalt material before placing aggregate. Additional aggregate shall be spread if necessary, and hand spreading shall be done to cover areas inaccessible to the spreading equipment. The aggregate shall be dried or moistened as required in order to obtain a near Surface Saturated Dry condition. If the process must stop during that application any asphalt material that has been applied to the surface shall be covered with aggregate to prevent breaking of the emulsi on prior to embedment of the aggregate. Application rate shall be taken from the design. 405.9 -ROLLING AND SWEEPING : Within 2 minutes following spreading of the aggregate, the entire surface of the aggregate shall be rolled until the aggregate is keyed into the asphalt material. Any area that ravels shall be repaired and rerolled. Rolling shall be parallel to the centerline and shall begin at the edges of the treatment and progress toward the center, each tri p uniformly overlapping the preceding trip. There shall be at least three passes made with a pneumatic tire roller. 188 Rolling shall cease before the aggregate is crushed to any appreciable extent. Rollers shall be the type and weight specified in subsectio n 405.4.3. To ensure aggregate embedment before the emulsion has set, the minimum number of rollers shall be three (3). More rollers may be used to obtain compaction to the satisfaction of the Engineer. The roller speed shall not exceed 3 miles per hour to prevent aggregate pick up and ensure embedment. Water, to prevent adhesion of the asphalt material to the roller wheels, shall not be used in excessive amounts. The use of fuel oil, paraffin oil, and kerosene on rollers or other equipment, for the purpo se of preventing material from picking up or sticking, is prohibited. After the emulsion has cured, sweeping can commence. The status of being cured shall be determined by the ability to sweep all loose aggregate from the surface without removing any aggregate adhered to the asphalt emulsion. TABLE 405.9 Project’s Annual Average Daily Traffic (AADT) - Sweeping Requirements Less than 500 AADT 501 to 5,000 AADT Greater than 5,000 AADT Within 24 hours after rolling No later than the following morning Before traffic is allowed without traffic control