Module 4-2 : Joint Sealing 4/13/2017 Chip Seals This module describes recommended materials and procedures for the application of chip seals on asphalt pavements. The following are possible initial discussion questions that can be used to assess the host agency’s practice. Q: How often do you use chip seals locally? Q: What functions do they serve? Q: What kind of construction or performance problems have you experienced? Q: How long do you estimate that your chip seals last?

Module 4-2 : Joint Sealing 4/13/2017 Learning Outcomes List the purposes of chip seal applications Describe different chip seal variations Describe recommended materials List the steps of the chip seal design process Build slide. Introduce these learning outcomes by stating “At the end of this module, you will be able to….” Ask the participants if there is anything specific that they hope to learn/discuss in the module. If an additional discussion topic (not covered in the list on this slide) is identified, write it on the flip chart for discussion later.

Learning Outcomes (cont.) Module 4-2 : Joint Sealing 4/13/2017 Learning Outcomes (cont.) Describe recommended construction procedures List key quality control activities Describe potential construction and performance problems Identify associated solutions

Module 4-2 : Joint Sealing 4/13/2017 Introduction Description Application of asphalt binder on existing pavement followed by a layer of aggregate chips. The treatment is then rolled to embed the aggregate into the binder. Chip seals are a type of pavement surface treatment in which one or more layers of crushed aggregate are “glued” to an existing roadway surface using an asphalt binder. Hot binder or lightweight chip on high volume roads. Commonly used on low-volume roads

Module 4-2 : Joint Sealing 4/13/2017 Project Selection Surface for light to medium traffic Waterproof layer Skid resistant surface Restore weathered surface Address bleeding Temporary base course cover Define shoulders Q: What types of applications make the choice of a chip seal an appropriate treatment candidate? Note: this is an indirect way of asking the class to identify the benefits/purposes of chip seal applications. A: This slide summarizes the purposes of a chip seal application. Historically used on low volume roads (< 2000 ADT) as a wearing surface on untreated granular roadbeds; however, they have more recently been used on higher volume roads (over 10,000 ADT) because of their ability to waterproof the surface, provide low severity crack sealing, and improve surface friction. The first Pavement Preservation International Scanning Tour reported the use of this treatment on high volume roads in both Australia and South Africa. The possibility of loose chips and traffic disruptions has limited the use of chip seals on higher volume facilities in the United States (Raza 1992). However, using a stiffer binder and a greater initial embedment of the aggregate chips has been shown to overcome loose chip problems (Shuler 1999). The list of chip seal uses shown on this slide are from the Asphalt Institute’s Basic Asphalt Emulsion Handbook.

Module 4-2 : Joint Sealing 4/13/2017 Limitations Structurally deficient pavements Cracks >6 mm (0.25 in) wide Medium- to high-severity alligator cracking Large number of potholes Rutting >25 mm (1 in) Very rough surface This is a build slide that identifies pavement characteristics that make a chip seal an inappropriate treatment selection. As you show each limitation, ask the participants if they can identify why the characteristics makes a chip seal an inappropriate treatment. Like other thin surface treatments, chip seals provide no additional structure to the pavement. Wide cracks experience large movements that will reflect through the chip seal. More severe alligator cracking and potholes indicate a localized structural problem that needs to be addressed by another technique. Deeper rutting or a very rough surface will not be corrected with a chip seal application. Point out that rubber-modified chip seals have been used on more distressed pavements.

Module 4-2 : Joint Sealing 4/13/2017 Performance and Cost Performance Proper application of binder and aggregate Proper embedment Typical treatment life: 4 to 7 years Average cost $0.96/m2 to $1.32/m2 ($0.80 to $1.10/yd2) The performance greatly depends on the quality of the construction procedures. The cost data above is from the SPS-3 studies. Average cost data from Ohio showed a range of $0.96 to $1.32/m2 ($0.80 to $1.10/yd2). Cost can be $2.40 to 3.00/m2 ($2.00 to $2.50/yd2) for asphalt-rubber chip seals. New Zealand, Australia, and South Africa are constructing deep granular bases covered with chip seals and are getting 10 to 15 years performance.

What a Chip Seal Can & Can’t Do Module 4-2 : Joint Sealing 4/13/2017 What a Chip Seal Can & Can’t Do A Chip Seal CAN: Seal the surface of a roadway Restore or improve skid resistance Preserve a good road for 5 to 10 years A Chip Seal CAN’T: Increase the strength of a roadway Restore a failed roadway

Module 4-2 : Joint Sealing 4/13/2017 Chip Seal Variations Single chip seals Double or triple chip seals Cape Seals Sand seals Fabric and chip seals This slide lists the major chip seal variations. Each of these will be briefly introduced and illustrated in the upcoming slides. Detailed information on the chip seal variants may be found in reports by Raza (1992) and the Asphalt Institute (AI 1997). Schematic illustrations of these applications are shown in figure 2-4.1 on p. 2-4.3 of the Reference Manual.

Chip Seal Variations Single Chip Seals Module 4-2 : Joint Sealing 4/13/2017 Chip Seal Variations Single Chip Seals Pneumatic- Tired Roller This is an animated build slide. Hit a key or click the mouse to advance through the following steps of the process. Application of binder to the existing pavement. Application of larger sized aggregate. Pneumatic-tired rolling seats the aggregate to about 70% embedment. Curing of the binder is illustrated by the binder automatically changing to a gray color. Single (conventional) chip seals consist of the application of an asphalt or emulsion directly on the existing pavement, followed by the application of an aggregate that is rolled with a pneumatic roller. Emphasize that the majority of this presentation focuses on conventional single chip seals. Rubberized asphalt chip seals are similar to chip seals except that the asphalt binder is replaced with a blend of ground tire rubber (or latex rubber) and asphalt cement (Raza 1992). The rubber additive enhances the elasticity and adhesion characteristics of the binder. Rubberized asphalt chip seals are commonly used in conjunction with an overlay to retard reflection cracking. 70% Binder Existing Pavement

Chip Seal Variations Double Chip Seals Module 4-2 : Joint Sealing 4/13/2017 Chip Seal Variations Double Chip Seals Pneumatic- Tired Roller Pneumatic- Tired Roller Second Binder Application This is an animated build slide. Hit a key or click the mouse to advance through the following steps of the process. Application of binder to the existing pavement. Application of larger sized aggregate. First pneumatic-tired rolling seats the aggregate to about 70% embedment. Second binder application. Application of smaller sized aggregate. Final pneumatic-tired rolling seats the aggregate. Curing of the binder is illustrated by the binder automatically changing to a gray color. Double or triple chip seals are obtained through two or three applications of a chip seal operation over the same roadway, each subsequent layer being placed after the previous layer has cured. These multiple chip seals are dense-wearing, waterproofing applications that in some instances may approach thicknesses of 25 mm (1 in) (AI 1997). Binder Existing Pavement

Chip Seal Variations Cape Seals Module 4-2 : Joint Sealing 4/13/2017 Chip Seal Variations Cape Seals Pneumatic- Tired Roller Brooming Slurry Seal This is an animated build slide. Hit a key or click the mouse to advance through the following steps of the process. Application of binder to existing pavement. Application of larger sized aggregate. Pneumatic-tired rolling seats the aggregate to about 70% embedment. Brooming of the chip seal surface. Application of a Slurry Seal. Curing of the slurry seal and binder is illustrated by these layers darkening in color. Cape seals are a chip seal covered with a slurry seal and are used to provide a dense, waterproof surface with improved skid resistance (Raza 1992). For cape seals, the application of the slurry seal also helps reduce stone loss. Binder Existing Pavement

Chip Seal Variations Sand Seals Module 4-2 : Joint Sealing 4/13/2017 Chip Seal Variations Sand Seals Pneumatic- Tired Roller This is an animated build slide. Hit a key or click the mouse to advance through the following steps of the process. Application of binder to the existing pavement. Application of sand and small sized aggregate. Pneumatic-tired rolling. Curing of the binder is illustrated by the binder automatically changing to a gray color. Sand seals are similar to single chip seals, except that a sand or fine aggregate is used instead of a larger aggregate chip. Binder Existing Pavement

Chip Seal Variations Fabric and Chip Seals Module 4-2 : Joint Sealing 4/13/2017 Chip Seal Variations Fabric and Chip Seals Pneumatic- Tired Roller Binder Application This is an animated build slide. Hit a key or click the mouse to advance through the following steps of the process. Application of tack coat to existing pavement. Apply paving fabric. Application of chip seal binder on top of the fabric. Application of larger sized aggregate. Pneumatic-tired rolling seats the aggregate to about 70% coverage. Curing of the binder is illustrated by the binder automatically changing to a gray color. Paving Fabric Tack Coat Existing Pavement

Chip Seal Variations Fabric and Chip Seals Module 4-2 : Joint Sealing 4/13/2017 Chip Seal Variations Fabric and Chip Seals This photo shows the application of fabric on a freshly placed binder.

Material Selection Binder Module 4-2 : Joint Sealing 4/13/2017 Material Selection Binder Segue to the materials and mix design section. As demonstrated in the chip seal variation section, chip seal materials primarily consist of a binder and aggregate cover. The next few slides discuss specific binder and aggregate considerations.

Material Selection Binder Module 4-2 : Joint Sealing 4/13/2017 Material Selection Binder Rapid setting emulsions Polymer-modified emulsions Asphalt cement Rubberized asphalt Conventional chip seals typically use rapid setting emulsions (anionic grades RS-1, RS-2 or cationic grades CRS-1, CRS-2) that are designed to react quickly with the aggregate. Anionic grades are intended for use with positively charged aggregates (such as limestone) and the cationic grades are intended for use with negatively charged aggregates (such as siliceous gravel) (Roberts et al. 1991). Some agencies have used polymer-modified emulsions, particularly on high-volume roads. The polymer modification reduces temperature susceptibility, provides increased adhesion to the existing surface, and allows the road to be opened to traffic earlier (Zaniewski and Mamlouk 1996). A few agencies use asphalt cement as the binder for chip seals. Softer grades, such as AC-2.5 and AC-5, are recommended for use in chip seal applications (AI 1996), although AC-10 grade asphalts have also been used. Adhesion agents may be added to these asphalt cements to enhance chip retention. These are typically used in hot weather regions.

Material Selection Emulsion Ingredients Module 4-2 : Joint Sealing 4/13/2017 Material Selection Emulsion Ingredients Asphalt Water Emulsifying agent (surfactant) The three basic ingredients of an emulsion are listed here, along with some general discussion of their attributes. Rapid setting emulsion contains up to 35 percent water (compared to 43 percent for slow setting emulsions). Emulsifying agent – keeps asphalt droplets in stable suspension. Water impurities can be harmful.

Emulsion Nomenclature Module 4-2 : Joint Sealing 4/13/2017 Emulsion Nomenclature CRS-2P CATIONIC POLYMER MODIFIED RAPID SETTING HIGH VISCOSITY

Material Selection Emulsion Classification Module 4-2 : Joint Sealing 4/13/2017 Material Selection Emulsion Classification Electrical charge (+ or –) Speed of break: slow (SS), medium (MS), and rapid set (RS) Asphalt relative viscosity: hard (h) or soft (s) Polymer-modified asphalt (P or L) High float (HF) This slide is intended to give a brief introduction to emulsions. Specifically, it indicates the four factors that classify an asphalt emulsion: The charge is important because of its effect on the adhesion of the emulsion to the pavement surface and aggregate. The typical charge on emulsions used for pavement application are either anionic (negative) or cationic (positive). Anionic – Fatty acids or wood-product derivatives (tall oils, rosins, and lignins). Cationic – Fatty amines (diamines, imidazolines, and amidoamines). The speed of the break refers to how quickly the asphalt droplets in the emulsion coalesce after spraying. Different types of seals call for different break times. The relative viscosity refers to the degree of hardness of the asphalt binder used in the emulsion. A code is used to identify the type of modifier used in the asphalt binder, i.e., P for polymer and L for latex.

What is “AC” Asphalt Cement? Module 4-2 : Joint Sealing 4/13/2017 What is “AC” Asphalt Cement? Hot applied asphalt binder Generally graded by viscosity Typically modified with polymer or tire rubber to improve qualities

Asphalt Cement Nomenclature Module 4-2 : Joint Sealing 4/13/2017 Asphalt Cement Nomenclature AC-15P ASPHALT CEMENT POLYMER MODIFIED 1,500 + VISCOSITY

Material Selection Emulsion Classification Module 4-2 : Joint Sealing 4/13/2017 Material Selection Emulsion Classification Emulsion Type Slow Setting Medium Rapid Anionic SS-1 SS-1h MS-1 MS-2 MS-2h HFMS-1 HFMS-2 HFMS-2h HFMS-2s RS-1 RS-2 HFRS-2 Cationic CSS-1 CSS-1h CMS-2 CMS-2h CRS-1 CRS-2 This table illustrates some of the different emulsion classifications.

Module 4-2 : Joint Sealing 4/13/2017 Curing of Binder Time depends on temperature and relative humidity Emulsion break should begin just after first roller pass If delays occur, allowing the asphalt to set or cure before rolling is completed, chips will not be effectively seated, therefore, resulting in chip loss. Emulsion should ideally begin to break just after first roller pass. If potential for rock loss exists (with emulsions) traffic control will be required for a longer period of time.

Material Selection Rubberized Asphalt Chip Seal Module 4-2 : Joint Sealing 4/13/2017 Material Selection Rubberized Asphalt Chip Seal This photo illustrates the advantage of using rubberized asphalt chip seals.

Material Selection Aggregates Module 4-2 : Joint Sealing 4/13/2017 Material Selection Aggregates Clean and durable One size: 6 to 16 mm (0.25 to 0.6 in) Cubical shape Flat and elongated particles limited to 25 to 30 percent Fines limited to 1 to 2 percent Note: Pass around any aggregate samples you may have. Clean aggregates enhance the coating of the asphalt. Durable aggregates resist wear from traffic. The aggregate should be crushed and screened to as close to one size as possible (AI 1997). The size of the aggregate will largely dictate the resultant thickness of the chip seal. Flat or elongated particles tend to align on their flat sides and may be completely covered with asphalt, whereas rounded aggregate may roll under traffic and dislodge (AI 1997). Fines are limited to limit dust and ensure proper coating of aggregate. The goal is to achieve about 70 percent embedment of the aggregate after compaction of the chip seal, with additional embedment occurring from traffic (Raza 1992). More detailed information on typical aggregate gradations is summarized in table 2-4.1 (p. 2-4.8) and figure 2-4.3 (p. 2-4.9) of the Reference Manual.

Aggregate used for a chip seal Module 4-2 : Joint Sealing 4/13/2017 Aggregate used for a chip seal This is a crushed aggregate surface, which provides good skid resistance.

Module 4-2 : Joint Sealing 4/13/2017 Aggregate used for a chip seal This is a surface where pea gravel was used. It is important to be aware that when uncrushed aggregate, such as pea gravel, with the individual particles having rounded and smooth surface (as opposed to angular or jagged) is used, the road can become extremely slick when wet. The use of uncrushed aggregate is not recommended.

Module 4-2 : Joint Sealing 4/13/2017 Grade 3 crushed limestone, Colorado Materials Co.

Module 4-2 : Joint Sealing Grade 3 crushed limestone, asphalt coated, Colorado Materials Co. Module 4-2 : Joint Sealing 4/13/2017

Module 4-2 : Joint Sealing Grade 4 crushed limestone, Colorado Materials Co. Module 4-2 : Joint Sealing 4/13/2017

Module 4-2 : Joint Sealing Grade 4 crushed limestone, asphalt coated, Colorado Materials Co. Module 4-2 : Joint Sealing 4/13/2017

Module 4-2 : Joint Sealing Grade 5 crushed limestone, Colorado Materials Co. Module 4-2 : Joint Sealing 4/13/2017

Module 4-2 : Joint Sealing Type L, Grade 3 expanded shale aggregate, TXI Module 4-2 : Joint Sealing 4/13/2017 At the TXI plant in Streetman, TX, a coal-fired kiln expands and vitrifies raw shale inside a rotary kiln, forming lightweight aggregate.

Module 4-2 : Joint Sealing Type L, Grade 4 expanded shale aggregate, asphalt coated, TXI Module 4-2 : Joint Sealing 4/13/2017

Module 4-2 : Joint Sealing Type L, Grade 5 expanded shale aggregate, TXI Module 4-2 : Joint Sealing 4/13/2017

Module 4-2 : Joint Sealing Grade 3 crushed limestone rock asphalt, Vulcan Co. Module 4-2 : Joint Sealing 4/13/2017

Module 4-2 : Joint Sealing Grade 4 crushed limestone rock asphalt, asphalt coated, Vulcan Co. Module 4-2 : Joint Sealing 4/13/2017

Material Selection Problem With Flat Aggregates Module 4-2 : Joint Sealing 4/13/2017 Material Selection Problem With Flat Aggregates Pneumatic- Tired Roller Cracks in Aggregate This is an animated build slide that illustrates the problem with flat aggregates. Hit a key or click the mouse to advance through the following steps of the process. Application of binder to existing pavement. Application of larger sized aggregate. Pneumatic-tired rolling seats the aggregate to greater than 70 percent embedment. Curing of the binder is illustrated by the binder automatically changing to a gray color. Point out how the flat aggregates can become embedded too far (i.e., covered with binder). Binder Existing Pavement

Chip Seal Design Process Module 4-2 : Joint Sealing 4/13/2017 Chip Seal Design Process Assess existing pavement Select chip seal variation Select compatible binder and aggregate Quantity selection The four main parts of the chip seal design process are shown here. The first steps are to assess the existing pavement to make sure a chip seal is an appropriate treatment and to select the most appropriate chip seal variation. A critical part of the design process is the selection of a compatible binder and aggregate. For emulsions, this involves making sure that an emulsion with the correct particle charge is used with the chosen aggregate. The last step is the determination of the material quantities.

Design Considerations Quantity Selection Module 4-2 : Joint Sealing 4/13/2017 Design Considerations Quantity Selection Residual asphalt content Asphalt cement factor = 1.0 Emulsion factors range = 0.55 to 0.65 Aggregate application rate Single chip layer No more than 10% excess chips 70% embedment recommended The residual factor is the percentage of asphalt cement remaining after the other additives (water or solvent) have evaporated. In an emulsion, the water will evaporate along with a small amount of solvent. With any given aggregate size, there will be a difference between the necessary application rate for a cutback and the application rate for an emulsion to get the same residual asphalt and chip embedment. Emulsions generally have a lower residual ratio and require a higher application rate to get the same residual. The amount of residual asphalt should produce about 70 percent embedment of the stone after construction.

Chip Seal Design Methods Module 4-2 : Joint Sealing 4/13/2017 Chip Seal Design Methods McLeod procedure Asphalt Institute (Table 2-4.2 in the Reference Manual) The most common is the McLeod procedure that has been used since the late 1960s. To simplify this process, the Asphalt Institute prepared a design table (presented as table 2-4.2 on p. 2-4.12 in the Reference Manual) to estimate the quantities of asphalt and aggregate for single chip seals. Agencies may use this Asphalt Institute method as a general guide and modify the recommended rates based on local conditions and experience.

Asphalt Institute Method Module 4-2 : Joint Sealing 4/13/2017 Asphalt Institute Method Determine aggregate size and specific gravity Aggregate and asphalt emulsion quantities from table Adjust aggregate (if necessary) Adjust asphalt content based on condition of road (if necessary) This slide introduces the basic steps of the Asphalt Institute chip seal design method that uses table 2-4.2 (p. 2-4.12) in the Reference Manual. Note: Have class participants open the Reference Manual to look at this table. Determine the nominal aggregate size and the specific gravity of the aggregate. Find the row of the table that corresponds with the determined nominal aggregate size. Select an aggregate quantity, asphalt quantity, and grade of asphalt from the recommended values associated with the selected row (line). Adjust aggregate quantity (if necessary) based on specific gravity. The mass weight of the aggregate shown in the table is based on a specific gravity of 2.65. If the known specific gravity is lower than 2.55 or higher than 2.75, the aggregate amount in the table should be multiplied by the ratio of the actual aggregate specific gravity divided by 2.65. Adjust asphalt content (if necessary) based on pavement condition. The last step is to adjust the asphalt content based on the condition of the road. Use the five pavement descriptions at the bottom of table 2-4.2 (p. 2-4.12 in the Reference Manual) to adjust the asphalt content recommended in the table above.

Module 4-2 : Joint Sealing 4/13/2017 5 Keys to Success Repair old surface (90-180 days ahead) Calibrate equipment prior to use Inspect surface to determine rates Choose the right materials Timely application of asphalt and aggregate

Module 4-2 : Joint Sealing 4/13/2017 Construction Point out that although many different chip seal variations have been introduced in this module, this section focuses on the construction steps for a “conventional” single chip seal.

Construction Conventional Chip Seal Procedure Module 4-2 : Joint Sealing 4/13/2017 Construction Conventional Chip Seal Procedure Clean existing pavement Apply binder Spread aggregate Roll Allow binder to cure Broom loose aggregate The construction sequence for most chip seal projects is shown on this slide.

Construction Cleaning Existing Pavement Module 4-2 : Joint Sealing 4/13/2017 Construction Cleaning Existing Pavement The first step is to clean the existing pavement surface to ensure good bond with the applied asphalt. The existing pavement surface should be dry. The work should be conducted in warm weather, and should not be attempted when air temperatures are below 16 °C (60 °F).

Construction Start and Stop Application on Mat Module 4-2 : Joint Sealing 4/13/2017 Construction Start and Stop Application on Mat This photo shows construction paper set in place where the binder application is to start. Start and stop binder on construction paper. Makes a nice looking clean end to chip seal application. Shows good workmanship and complies with most specifications.

Construction Binder Application Module 4-2 : Joint Sealing 4/13/2017 Construction Binder Application This photo shows the application of asphalt on the existing pavement.

Construction Binder Overlap Module 4-2 : Joint Sealing 4/13/2017 Construction Binder Overlap Spray Bar and Nozzles h h h Single Overlap Double Overlap Roadway Surface Roadway Surface Triple Overlap Roadway Surface Build slide. Illustrates single, double, and triple overlap. Point out to the participants that best results are usually achieved with double overlap, although triple overlap can sometimes be used for spray bars with nozzles spaced at 100-mm (4-in) intervals (AI 1997). Note that spray fans at a higher height setting may be susceptible to wind effects.

Construction Binder Application Overlap Module 4-2 : Joint Sealing 4/13/2017 Construction Binder Application Overlap This photo shows a close up of the application of asphalt on the existing pavement. This slide illustrates the triple overlap. Also, point the participants to figure 2-4.6 on p. 2-4.14 in the Reference Manual. Triple Overlap

Construction Binder Application Module 4-2 : Joint Sealing 4/13/2017 Construction Binder Application This photo shows a further close up of the spray nozzles applying asphalt on the existing pavement.

Binder Application Asphalt Distributor—Spray Nozzles Module 4-2 : Joint Sealing 4/13/2017 Binder Application Asphalt Distributor—Spray Nozzles 15o 45o 90o Travel Direction Lateral Coverage This diagram demonstrates the effects of nozzle orientation on later coverage of the emulsion application. The top of this diagram depicts the top view of nozzles with varying degrees rotation. The typical orientation of the nozzles (with respect to the spray bar) is between 15 and 45 degrees.

Construction Aggregate Application Module 4-2 : Joint Sealing 4/13/2017 Construction Aggregate Application This photo shows an aggregate (or chip) spreader. A self-propelled, pneumatic-tired, motorized unit has a hopper on the front where the chips are dumped. The chips are then transported to the back where a specialized gate system drops the chips uniformly across the pavement. This equipment also includes a screen on the hopper to reject oversized rock, individually controlled gates that allow varying rock application rates across the pavement, and a system using sloped screens that can separate out the larger chips and drop them ahead of the smaller chips.

Construction Aggregate Application Module 4-2 : Joint Sealing 4/13/2017 Construction Aggregate Application This photo shows the spreading of chips behind the asphalt applicator truck.

Module 4-2 : Joint Sealing 4/13/2017 Construction Rolling Immediate rolling of aggregate Pneumatic-tired rollers No fewer than three passes Full coverage necessary before asphalt hardening Rolling begins immediately after the aggregate has been spread to seat or embed the chips (not compact them). Typically, 4.5 metric ton (5 T) pneumatic-tired rollers are used, although rollers with weights of 2.7 metric tons (3 T) to 7.3 metric tons (8 T) are also used. Steel-wheeled rollers are not used because they may crush the aggregate and have a tendency to bridge over low spots so that no embedment occurs in those areas. Once the asphalt begins to harden, the aggregate cannot be adequately seated and may be pulled out by traffic. The maximum amount of rolling should be determined by costs, while the minimum amount should be no fewer than three passes.

Module 4-2 : Joint Sealing 4/13/2017 Construction Rolling This photo shows two pneumatic-tired rollers.

Module 4-2 : Joint Sealing 4/13/2017 Construction Rolling Another photo of pneumatic-tired rollers rolling the chip seal close to the aggregate supply truck.

Construction Curing of Binder Module 4-2 : Joint Sealing 4/13/2017 Construction Curing of Binder Time depends on temperature and relative humidity Emulsion break should begin just after first roller pass Open to traffic in about 2 hours If delays occur, allowing the asphalt to set or cure before rolling is completed, chips will not be effectively seated, therefore, resulting in chip loss. Emulsion should ideally begin to break just after first roller pass. If potential for rock loss exists (with emulsions) traffic control will be required for a longer period of time.

Construction Brooming Loose Aggregate Module 4-2 : Joint Sealing 4/13/2017 Construction Brooming Loose Aggregate After the binder is cured the surface is swept to remove loose (non-embedded) chips. The typical timing of sweeping is between 15 to 24 hours after the application of the chips. A chip seal with a hot binder can be broomed much sooner than a chip seal with an emulsion.

Quality Control Preliminary Responsibilities Module 4-2 : Joint Sealing 4/13/2017 Quality Control Preliminary Responsibilities Project review Document review Material checks Preliminary responsibilities include project review, document review, and materials checks. A detailed listing of quality control preliminary responsibility tasks can be found in table 2-4.4 on page 2-4.16 of the Reference Manual. Some project review questions include the following: Is the project a good candidate for a chip seal? What types of distresses are present and at what extent and severity levels? Is crack sealing needed? Is existing bleeding/flushing expected to be a problem? For the following two questions see how many answers the class participants can come up with without looking in the Reference Manual. Possibly write answers on white board. Q: What types of documents should be reviewed prior to construction? A: See the list below: Bid specifications. Special provisions. Construction manual. Traffic control plan. Agency requirements. Manufacturers instructions. Material safety data sheets. Q: What types of material checks are required prior to construction? Compatibility between emulsion and aggregate. Confirm that asphalt is from an approved source (if required). Asphalt is sampled and submitted for testing (if required). Aggregate chips are close to same size, clean, and free of excess fines. Asphalt application temperature range is specified.

Quality Control Pre-Application Inspection Module 4-2 : Joint Sealing 4/13/2017 Quality Control Pre-Application Inspection Surface preparation Equipment inspection Asphalt distributor Chip spreader Haul trucks Rollers Brooms This slide highlights some of the pre-application inspection activities included in a quality control plan. A more detailed listing of these quality control tasks can be found in tables 2-4.5 and 2-4.6 on page 2-4.17 of the Reference Manual.

Quality Control Pre-Application Inspection (continued) Module 4-2 : Joint Sealing 4/13/2017 Quality Control Pre-Application Inspection (continued) Weather requirements Determining application rates Checking application rates Traffic control plan and setup This slide highlights some of the pre-application inspection activities included in a quality control plan. A more detailed listing of quality control tasks can be found in tables 2-4.5 and 2-4.6 on page 2-4.17 of the Reference Manual.

Quality Control Project Inspection Module 4-2 : Joint Sealing 4/13/2017 Quality Control Project Inspection Asphalt application Aggregate application Truck operation Rolling Longitudinal joints Transverse joints Brooming This slide highlights some of the project inspection activities included in a quality control plan. A more detailed listing of quality control tasks can be found in table 2-4.9 on page 2-4.19 of the Reference Manual.

Quality Control Post-Application Inspection Module 4-2 : Joint Sealing 4/13/2017 Quality Control Post-Application Inspection Cleanup Opening to traffic This slide lists two post-application activities included in a quality control plan.

Module 4-2 : Joint Sealing 4/13/2017 Quality Control Plan Class groups: preliminary responsibilities, pre-application inspection, and project inspection Label QC items as Always Included, Sometimes Included, or Frequently Omitted Use Reference Manual and your experience This slide introduces workshop 2-4.2 on quality control methods. Try to keep this exercise to about 20 to 25 minutes total. Worksheets for this exercise are found on p. 2-4.47 of the Instructor Guide and on p. 2-4.33 of the Participant Workbook. The objectives of this exercise are to use the provided course materials to identify those QC items recommended for inclusion in a comprehensive QC plan, and to understand how each of those QC items affects treatment performance. Divide the class into groups associated with preliminary responsibilities, pre-application inspection, and project inspection and post-application inspection considerations. If a fourth group is needed, consider instructing the fourth group to think “out of the box” in an effort to try to come up with QC items that groups one, two, and three may forget to include. Note: pay close attention to the progress of each group as the workload may become unbalanced. If the workload between groups does appear unbalanced, you may want to assign specific task items to groups that finish early. Each group should first use a combination of the Reference Manual and their experience to put together their own QC checklist for their assigned topic. Group members should discuss their agency’s current practice and determine if each listed item is Always Included, Sometimes Included, or Frequently Omitted from the host agency’s list of QC activities. The point here is to generate discussion/debate over how important each QC item is to obtaining a good quality treatment. Each group should elect a group spokesperson. After about 15 to 20 minutes, the group’s spokesperson should report the findings back to the class.

Module 4-2 : Joint Sealing 4/13/2017 Chip Seals This module describes recommended materials and procedures for the application of chip seals on asphalt pavements. The following are possible initial discussion questions that can be used to assess the host agency’s practice. Q: How often do you use chip seals locally? Q: What functions do they serve? Q: What kind of construction or performance problems have you experienced? Q: How long do you estimate that your chip seals last? QUESTIONS?