### S **OUTH COAST AIR QUALITY MANAGEMENT DISTRICT**

**TECHNICAL ASSESSMENT FOR RULE 1108**

**– CUTBACK ASPHALT** 

**June 2008** 

**Deputy Executive Officer Planning, Rule Development, and Area Sources**  Elaine Chang, DrPH **Assistant Deputy Executive Officer Planning** **, Rule Development, and Area Sources** Laki Tisopulos, Ph.D., P.E. **Planning and Rules Manager VOC Rule Development**  Larry Bowen, P.E.

Author : Bill Milner

- Air Quality Specialist Reviewed By: Andrew Lee , P.E.
- Program Supervisori **TABLE OF CONTENTS** 

**EXECUTIVE SUMMARY ................................**  **................................ ................................**  **.......... 1**  **BACKGROUND ................................**  **................................ ................................**  **........................... 1**  **TECHNOLOGY ASSESSMEN T**  **................................ ................................**  **................................ 2**  **Hot Mix Asphalt ................................**  **................................ ................................**  **................................ ......**  **2 Warm Mix Asphalt**  **................................ ................................**  **................................ ................................**  **. 3**  **Cutback Asphalt ................................**  **................................ ................................**  **................................ .....**  **3 Emulsified Asphalt**  **................................ ................................**  **................................ ................................**  **. 4**  **GENERAL PAVING USES OF LIQUID ASPHALTS**  **................................ .............................**  **5 UNIVERSE OF SOURCES**  **................................ ................................**  **................................ .........**  **5 EMISSIONS INVEN**  **TORY ................................**  **................................ ................................**  **......... 5**  **COMPARATIVE ANALYSIS ................................**  **................................ ................................**  **..... 8**  **CONCLUSIONS AND RECO MMENDATIONS**  **................................ ................................**  **...... 9**  **REFERENCES ................................**  **................................ ................................**  **.......................... R** **- 1**  **KEY CONTACTS ................................**  **................................ ................................**  **..................... R** **- 1**  **APPENDIX A**

**– EXAMPLE RULE CONTAIN**  **ING SEASONAL EXEMPTI ON**  **............ A** **- 1** **Technology Assessment for Rule 1108** 

**– Cutback Asphalt** 

1 **EXECUTIVE SUMMARY** As recommended by

the United States Environmental Protection Agency (U.S. EPA), the 2007 Air Quality Management Plan (AQMP) included Control M easure FUG
- 03
- Further Emissions Reductions from Cutback Asphalts, which commits the District to explore the feasibility o f further limiting the use of cutback asphalt to the fall and winter months where ozone formation is at its least, or replacing it altogether with surrogate water-based emulsion technology

. The only type of cutback asphalt being used today for paving, road construction and maintenance is slow cure cutback asphalt

. S low cure cutback is a blend of asphalt binder, a by product of the distillation of crude oil , and twenty to thirty p ercent by

volume heavy nonvolatile oil such as diesel fuel or gas oil. The main use of slow cure cutback asphalt is stockpiled temporary cold

mix maintenance patching material consisting of graded aggregate and small quantities of cutback asphalt, enough to coat the aggregate and bind it in place under compaction, and as a dust palliative on the road construction jobsite. Previous District rulemaking has eliminated the use of faster curing cutback asphalt known as “rapid” cure and “medium” cure cutbacks. These materials contained lighter fractions of oil such as naphtha and kerosene and were problematic to air quality because they c ontained more evaporative oil by

volume that flashed off more readily

. Ninety-nine point five percent by volume of the cutter stock used to make cutback asphalt , as required by R ule 1108, cannot evaporate when tested under ASTM distillation Method D402 at 500oF or less

. Therefore, it cannot evaporate at application or atmospheric temperature s . The potential to emit volatile organic compounds (VOCs ) from slow cure asphalts is de minimus. Emulsified asphalts that are suitable replacements for stockpiled slow cure cutback asphalt will contain a small fraction of evaporative VOCs. Under Rule 1108. 1

– Emulsified Asphalts, they are prohibited to have more than three percent by volume VOCs that evaporate at 500oF or less

. S ubstitution to an emulsion at this point will not benefit the environment , because replacement emulsions for slow cure asphalt wi ll contain up to three percent VOCs. It is important to note that replacement emulsions have already taken the place of the more volatile medium and rapid setting cutbacks , and therefore have substantially reduced emissions to date

. City streets , county roadways, and state highways can be repaired with slow cure cutback asphalts and with very limited VOC emissions. They are needed ye ar round in our sprawling metropolis, not just in seasons where smog formation is at its least. **BACKGROUND** A sphalt is found in nature and mined, but it is mostly manufactured as the remnants of crude oil distillation. Approximately 90 percent of the world’s asphalt is used in road construction. In general, asphalt is too firm at standard temperature and has to be liquefied e ither by heating it, mixing low

-volatility cutting oils (cutback asphalt) , or combining it with water, surfactant, and an emulsifying agent (emulsified asphalt)

. Once fluid, it is used as a binder for aggregate, a primer for new road construction, a tack coat between layers of asphalt concrete, a road surface sealer, and a road maintenance material. The amount of extremely l ow volatile cutter oils (gas oil, diesel fuel, and trace amounts of lighter distillates) used today range from 20 to 30 percent by vo lume

.**Technology Assessment for Rule 1108** 

**– Cutback Asphalt** 

2 Rule 1108

– Cutback Asphalt was adopted in May o f 1979 , and amended three times, to address the high air emissions from rapid curing, and to a lesser extent medium curing asphalts which contain lighter cutter oils that evaporate much more readily. Prior to September of 1983, the U.S. EPA opposed exemptions in Rule 1108 allowing the use of higher volatility cutback asphalts in areas where the elevation is higher that 2 , 000 feet above sea level , for penetrating prime coats , or when the temperature was forecast to be less than 50o F in the vicinity of the asphalt application. The 1983 amendment to Rule 1108 eliminated these exemptions. The rule now simply

limits the use of cutback asphalts to one -half percent by volume of volatile organic compounds (VOCs) that evaporate at 500oF or less, as determined by A STM distillation method D402
. During the 2007 AQMP development, the AQMD submitted to U.S. EPA a report to demonstrate that current AQMD rules and regulations fulfill the 8
-hour ozone RACT (Reasonably Available Control Technology)

. During this review, EPA Region IX noted that District Rule 1108 does not meet RACT for cutback asphalt, because other local air districts within the United States with similar rule s to Rule 1108 have seasonal restrictions on the use of cutback asphalt during spring and summer months ; the ozone season. Due to this c oncern by EPA, the AQMD developed C ontrol M easure FUG
- 03 (Further Emissions Reductions from Cutback Asphalts ) in its 2007 AQMP , with the purpose of limiting the use of cutback asphalt to the fall and winter months (November through February) where ozone formation is at its least or replacing it altogether with surrogate emulsion technology

. Asphalt emulsions are regulated under Rule 1108.1
- Emulsified Asphalt , which limits the quantity o f organic compounds that evaporate at 500oF or less , as determined by A STM Method D402, to three percent by volume for all ty

pes of emulsions be it rapid, medium, or slow setting ty pes . This value was arrived at through incremental VOC limitation reductions through the beginning of 1987, previously based on the U.S. EPA’s C ontrol T echnique Guidelines (CTG) for asphalt emulsions. **TECHNOLOGY ASSESSMEN T**  There are four groupings of asphalt products used during road, parking lot, runway, driveway and walkway

c onstruction and maintenance. They are hot mix asphalt (HMA), warm mix asphalt (WMA), cutback asphalt, and emulsified asphalt. Rule 1108

– Cutback Asphalt and its related Rule 1108.1

– Emulsified Asphalt represent both form s of so lution asphalt binder, whereas HMA and WMA are mixes of asphalt binder and aggregate. **Hot Mix Asphalt** HMA is a mixture of asphalt binder and aggregate conducted at a mixing plant (stationary or portable). A sphalt binder is heated to melting then combine d in a pug mill with clean, dried aggregate of a graded size and density. The mix contains approximately 95 percent aggregate and 5 percent asphalt binder to coat the aggregate in the temperature range of 260oF
- 325oF . It is supplied to trucks that deliver the HMA to the job site , where it is loaded into a paver that lays the mix down and is subsequently compacted with a roller to a prescribed density and thickness usually b etween 2 and 6 inches and at a delivery temperature of approximately 2 00oF
. B ecaus e the asphalt binder is the residue from the distillation from crude oil, it contains virtually no**Technology Assessment for Rule 1108** 

**– Cutback Asphalt** 

3 remaining VOCs. The asphalt binder is chosen on the basis of its minimum flash point, viscosity at 135oC, ductility

at 25oC , and its rolling thin film oven test results ; that tests for dy namic shear, ductility, and creep stiffness of aged binder, and they are further graded by

p enetration. The most common asphalt binder classifications are: penetration grade, viscosity grade and performance grade. These asphalt grades are specified in HMA mix design. Iti s HMA that replaces temporary

patch es of cold

-mix slow cure cutback asphalt (aggregate and cutback mixed together), that so many departments of transportation use in stockpiles. **Warm Mix Asphalt** This techno logy

uses emulsion (water

-based) technology together with additives that foam when added to less hot aggregate/asphalt mix. The result is a thin

- film, high volume asphalt binder with greater aggregate coating potential than HMA
. The process reduces the viscosity of the asphalt binder through foaming. Lower viscosities mean lower heat input required when mixing, transporting, and applying, resulting in an energy s avings and lower emissions from the combustion of fuels used to heat the mix. The foaming additives are based on zeolite and combinations of soft binder and foaming hard binder cement
. B oth result in lowering the viscosity o f the asphalt, and lowering the energy requirements. Other warm technologies are based on sy

nthetic paraffin wax and low mo lecular weight ester compounds that reduce the viscosity o f the asphalt binder during mixing. Still others inject water into the mix to create a controlled sudden vaporization or explosion to coat the aggregate in a thin

- film in the mill. **Cutback Asphalt** Cutback asphalts made from various grades of asphalt binder and are blended with kerosene or naphtha that more rapidly evaporate s to leave hard viscous asphalt behind (rapid cure) , to a slowly evaporative asphalt/gas - oil blend that leaves a softer, less vi scous base to combine with aggregate (slow cure)

. Medium curing products are also available such that the hardness and viscosity o f the binder is between the rapid and slow curing ty pes (medium cure)

. There are several uses for cutback asphalts: prime co ats, tack coats, dust control, and cold mix applications for temporary road repairs (potholes and cuts for public utility services , etc. ). Prime coats are use d to provide a temporary w aterproofing layer and for stabilizing the first course of new construction and promoting a bond to the HMA layer. T ack coats are used in between layers of asphalt concrete to provide good bonding

. Dust control refers to bonding of loose dust

. C old

-mix is a combination of aggregate and slow cure asphalt ; depending on ty pe , it can be made for immediate use or stockpiled for later application

. The only use of cutback asphalt within the Departments of Tran sportation within the South Coast Air Basin today

i s slow cure (SC) cutback asphalt of the softest variety, used principally f or temporary road repair. The grades in use are SC
- 800 (immediate use) and SC
- 3000 (stockpiled)

. Some use of SC
- 70 and SC
- 250 may occur for prime coats in new parking lot and driveway construction ; the higher the visco sity, the higher the specification number. Tack coating with cutback asphalt has been replaced with emulsified asphalt. Slow cure asphalt by

definition and regulation may only contain up to one -half percent by volume of VOCs that evaporate at less than or equal to 500oF. This means that 99.5 percent by volume of the cutter oil will not evaporate at ambient air conditions. The associated air**Technology Assessment for Rule 1108** 

**– Cutback Asphalt** 

4 emissions are a maximum of 0.0 1125 pounds of VOC per applied gallon at 30 percent cutter oil , or 1 .35 gram s of VOC emissions per applied liter. **Emul sified Asphalt**  Emulsified asphalt are made with various grades of asphalt (hard, medium, and soft) that has been sheared in a colloidal mill to form globules, combined with surfactant, water, and soap as an emulsifying agent that leaves asphaltic particles suspended in solution. They are ionic in nature are will either have a negative charge (anionic), or a positive charge (cationic) for use in road and pavement applications. They c ontain less asphalt solids than slow cure cutback; approximately

65 percent by

volume compared to 75 percent by volume for cutback, so it takes a greater amount of emulsi fied asphalt compared to cutback asphalt to complete the same job. Ani onic emulsions are based on reacting fatty acids with chemical base to form a salt. It i s the salt that will attach itself to an asphalt particle with a non polar tail and a polar head (

- ). The polar head is balanced by f ree charges in the water phase. C ationic emulsions are based on acid salts of amines prepared f rom fatty acids. They wor

k the opposite way

o f anionic emulsions with positive head and a non polar tail attached to an asphalt particle. Once the asphalt globules begin to come together , or “break”, the asphalt will eventually return to its original solid or semi

- solid phase. In the anionic emulsion formula the asphalt particles and the aggregate particles will repel each other until the attractive forces between all things overcomes the repulsion and begins to flocculate the particles into larger particles upon evaporation , and further coalesce into a uniform asphalt residue. It is the point of flocculation that the solution begins to break

. This can be forced along by pumping the material at high shear, or heating or freezing. Cationic formulas break in a similar manner but deposit more rapidly on aggregate due to the electrostatic attraction of the positively charged emulsion and the negatively charged mineral matter, and stronger bonds between the asphalt and aggregate are obtained. C ationic emulsions are easier to apply and obviate many of the disadvantages of anionic emulsions, such as unpredictable break and a weaker bond to the aggregate surface
. The rate of set is determined by the ty pe and the amount of emulsifier and the pH of the cationic soap solution. Some emulsi ons have a relatively short shelf life and can break while still in their unopened drums , rendering it useless

. The break point can be extended by the choice of emulsifier, by shearing the binder into smaller globules , or by adding stabilizer

. All of the above asphalt system ty pes can contain modifiers. M odifiers improve the asphalt binder’s stiffness , which improve the resistance to form ruts and reduce cracking while in service. S ome of the modifiers used are latex, poly mers, and ground tire rubber. Additions of modifiers increase the cost of the asphalt binder but the increased cost is usually o ffset by l ess maintenance and increased lifetime of the asphalt pavement. According to the literature, emulsions are developed for every aspect of critical maintenance and construction including all plant and mix

- in

-place pavement bases and surface treatments including chip seals, tack coats, dust suppressants , crack fillers, and maintenance mixes for immediate and stockpiling use. Stockpile mixes (cold

-mix temporary p atch material) use about 10 percent of the total emulsion volume added as diesel or kerosene

.**Technology Assessment for Rule 1108** 

**– Cutback Asphalt** 

5 As per Rule 1108.1, the maximum allowable air emissi ons of emulsified asphalts are three percent by

volume. This would equate to approximately 0.2 0 pounds of VOC emitted per gallon of equivalently applied asphalt , and about 18 times more emissive than slow cure asphalts on a concentration basis

. **GENERAL PAVING USES OF**  **LIQUID ASPHALTS**  The American Society for Testing and Materials (ASTM) specification D 2399
- 83

– Standard Practice for Selection of Cutback Asphalt and D 3628
- 08

– Standard Practice for Selection and Use of Emulsified Asphalts outlines the general uses for both ty pes of solution asphalts, emulsified and cutback, according to their respective grades (slow, medium, and rapid setting cutback, anionic and cationic emulsions)

. The use of cutback asphalt is for prime coating with SC
- 70 or SC
- 250 grade s, whereas SC
- 800 and SC
- 3000 are cold

- laid plant mixes with dense

graded aggregate , for immediate and stockpil ed applications. In the case of rapid setting emulsions, mainly used for repair work of old wearing courses, the emulsion is applied on the existing surface and aggregate is spread on top, and after compaction, the road can be opened to traff ic shortly after the application of the new coat
. These are generally road surface treatments involving graded aggregate, sand, or aggregate chips imbedded into the roadway

. Medium setting emulsions are used for hot and cold plant mixes and for mixing with aggregate on the job

- site with portable equipment (mix

- in

-place)

. Slow setting emulsions are the most versatile with applications for cold plant mixes, mix

- in

-place, for low viscosity, penetrative bond coats or tack coats between new layers of asphalt concrete , and for crack filling. Only

one emulsion is recommended for stockpiled maintenance mixes as a high

– float medium setting soft variety

. Safety data sheets indicate the inclusion of cutter stock into the emulsion for this ty pe , presumably to retard the break and potentially increasing air emissions

. **UNIVERSE OF SOURCES** There are at least five refineries that manufacture asphalt for paving operations within the South Coast Air Basin. They

are Edgington Oil, Lunday

- Thaggard, Paramount, Owens Corning , and Valero

. Hot mix asphalt plants are numerous and include Vulcan Materials Company, All American Asphalt, Industrial Asphalt , and Sully

- Miller Contracting Company and they also formulate cutback and emulsified asphalt products. There are literally hundreds of contractors and applicators. S ome cities and counties have their own crews to address maintenance operations and surface treatments
. All other work is usually performed by p avement contracting companies. **EMISSIONS INVENTORY** As background infor

mation, staff contacted CALTrans which is responsible for highway construction and maintenance, the Los Angeles County Public Works Department, the San Bernardino Transportation Department, the Orange County Public Works Department, as well as the Riversi de County

Transportation to inquire on the use of cutback asphalt. M ost county representatives related the use of slow cure asphalts for temporary road maintenance (SC

- 800 and SC
- 3000). T emporary c an mean backfilled with HMA after a few days to several months or even longer. S low cure cutback asphalt as a dust palliative was also mentioned in use by industry representatives. P ertinent associations such as the Asphalt Emulsion Manufacturers**Technology Assessment for Rule 1108** 

**– Cutback Asphalt** 

6 Association, the Asphalt Pavement Association of California and membership representatives, as well as the asphalt manufacturers were contacted. The presented inventory

i s based on a report by

S onoma Technology

Inc., under contract by

the California Air Resources Board circa 2001
. The data generated is based on the number of road miles in the four county

areas that encompass the South Coast AQMD, and approximations were used as to the amount of asphalt contained in one road mile (10 tons/mile) , and an allocation factor is derived from the product of statewide emission s to the ratio of county road miles to state road miles. This is then used as a factor against the reported statewide asphalt consumption to obtain approximations of the amount of asphalt consumed by e ach AQMD County
. The total quantity o f asphalt sold in California is from state energy data as reported by the Energy In formation Administration (EIA) as of 2005
. The fraction of asphalt binder used for pavement is stated to be 88 percent of the total California State consumption of asphalt binder as reported by the EIA. U sage factors are then applied using historical reported data from local air districts with regard to the percentage of road miles of asphalt using HMA (88 percent) , cutbacks (1 percent), road oils (slow cure cutbacks) (2 percent) , and emul sions (9 percent)

. C onversions are then made using the maximum allowable emission factor of Rule 1108 (0.5 percent by volume) , as well as physical data available for cutback SC
- 800 and SC
- 3000 (diluent density, cutback density, volume asphalt binder, volume of cutter stock, etc.)

. An example calculation is given below and Table 1 shows all counties and totals the inventory

. Gallons of Asphalt Binder Used in Lo s Angeles County f or Cutback Asphalt = (Total CA Asphalt Binder Usage in bbl) x (Fraction Used f or Paving in CA) x (Fraction A sphalt Binder in Use for Slow Cure Cutbacks in CA) x (Los Angeles County Allocation Factor) x (42 gal/bbl) Gallons of Cutback Asphalt Used in Lo s Angeles County = (Number of Gallons of Asphalt Binder Used in Los Angeles County in California) + (Number of Gallons of Cutter Stock in Cutback Asphalt), Where , the number of gallons of cutter stock is proportional to the total gallons of binder used to make specific cutback asphalts . Annual Emissions for Los Angeles County =(Total Gallons of Cutback Asphalt Used in Los Angeles County) x (Emissions Factor in lb/gal) Los Angeles County : (13,843,000 bbl/y

r) x (0.88) x (0.02) x (0.084) (42 gal/bbl) = 859,551 gallons of asphalt binder 859,551 gal binder x (0.3 gal cutter stock/0.7 gal binder) = 368,379 gallons of cutter stock 859,551 + 368,379 = 1,227,820 gallons of cutback asphalt (1,227,820 gallons of cutback asphalt) x (0.01125 lb VOC emitted/gal) = 1 3 , 813 lb VOC/y r = 38 lb VOC/day**Technology Assessment for Rule 1108** 

**– Cutback Asphalt** 

7 The use of slow cure cutback asphalt in Orang e and Riverside Counties is assumed to occur with mid

-point cutter stock (25 percent by volume gas oil or similar cutter stock), whereas Los Angeles and San Bernardino Counties use 30 percent and 2 0 percent by volume cutter absolutely

. **Table 1: Emissions Inventory for Rule 1108** 

**– Cutback Asphalts**  **Location VOC Emissions From Asphalt** 

**California** Total State

Asphalt Binder Usage Total

Asphalt Binder Used for Paving Asphalt

Binder In Use for HMA and WMA Asphalt

Binder in Use for Emulsions Asphalt

Binder in Us e for Slow Cure Cutbacks Asphalt

Binder in Use for Slow Cure Cutbacks Percentage of Use 100% 88% 88% 9% 2%
- Barrels/Year 13,843,000 12,181,840 10,720,019 1,096,366 243,637
- Gallons/Year

- - - - - 10,232,746

Percent by Volume Gas Oil or Similar Material in Slow Cure Cutbacks County

Allocation Factor Approx.

Volume (Gal) SC Cutback Used Per AQMD County Per Year Pounds of

VOC Emitted per Gallon of Cutback Asphalt VOC

Emissions (lb/y r) VOC Emissions (lb/day)
**Los Angeles** 30.00% 0.0840 1,227, 820 0.01125 13,814 38 **Orange** 25.00% 0.0225 306,982 0.00938 2,87 9 8 **Riverside** 25.00% 0.0414 564,848 0.00938 5,29 8 15 **San Bernardino**  20.00% 0.0817 1,045,019 0.00750 7,838 21 Total 8 2 **Tons VOC/Day 0.0**  **4** The replacement of slow cure cutback asphalts with emulsion s that perform the same function will result in potentially

higher emissions , based on the upper evaporative VOC limit in Rule 1108.1 (3 percent b y volume) . See Table 2. An example calculation is given below : Los Angeles County : (Solids Adjustment Factor) x (Volume of SC Cutback Used) x (Density o f Ty pical VOC in Replacement Emulsion s ) x (Volume Percent VOC Allowable in Rule 1108.1)**Technology Assessment for Rule 1108** 

**– Cutback Asphalt** 

8 (0.70/0.65) x (1, 227,820 gal) x (6.6 lb VOC/gal of VOC) x (0.03 gal VOC/gal emulsion) = 2 61 ,809 lb VOC/y

r [if emulsion substitution occurs] **Table 2: Emission Inventory if Substitute Emulsions Replace Cutbacks** 

**Location** Volume

Fraction of Asphalt Binder in Specific SC Cutback Asphalt Used Per County Volume

Fraction Asphalt Binder in Emulsified Asphalt Approx.

Volume (Gal) SC Cutback Used Per AQMD County Per Year Approx.

Gallons of Substitute Emulsion Emissions

From Emulsion (lb/y r)
**Los Angeles** 0.70 0.65 1,227,820 1,322,386 261,8 09 **Orange** 0.75 0.65 306,982 354,210 70,134 **Riverside** 0.75 0.65 564,848 651,747 129,046 **San Berna**  **rdino** 0.80 0.65 1,045,019 1,286,177 254,663 Total 715,6 52 Tons/Day **0. 98**  Therefore, the use of emulsion technology c annot replace slow cure cutback because it will not result in a positive environmental impact. **COMPAR**

**A TIVE ANALYSIS**  Rule 1108

– Cutback A sphalt currently prohibits the use of medium and slow curing cutback asphalt that contains more than 0.5 percent by v olume organic compounds which evaporate at 500oF or lower as determined by ASTM Method D402 , and is specific to pavement applications

. The EPA CTG calls for substitution of emulsified asphalt for cutback asphalt. Its “Blue Book” suggests seasonal exemptions (i.e., outside of the ozone season) as opposed to temperature forecasting (e.g., applied when <50oF), and specifies (1) no higher than 7 percent oil distillate as maximum allowable solvent content in emulsified asphalt, as determined by A STM distillation test D244 or (2) allow use of certain grades or applications of emulsified asphalt with the following maximum solvent contents as determined by ASTM D244: (a) 3 percent limit for seal coats used in early spring or late fall; (b) 3 percent limit when chip seals used with aggregate that is dusty or dirty ; (c) 8 percent limit when mixing with open graded aggregate that is not well washed ; and (d) 12 percent limit when mixing with dense graded aggregate. Other exemptions are listed for use solely for penetrating prime coats and when stockpiled for extended periods.**Technology Assessment for Rule 1108** 

**– Cutback Asphalt** 

9 According to the 2007 AQMP, Control Measure FUG03, many states, such as M aine , Missouri, New York, Penns ylvania, and Rhode Is land have adopted rules on cutback asphalt that prohibit their use during the ozone season. (See Appendix A for an example from the State of Missouri). However, they

provide exemption for every application they are actually used for including, prime coats, stockpile d material for pothole and road patching, as well as dust palliatives on the jobsite

. Allowing for these exemptions completely negates the seasonal restriction. **CONCLUSIONS AND RECOM M** **ENDATIO NS**  AQMD Staff has reviewed the potential for limiting cutback asphalt or replacing it altogether with emulsion technology and concludes that slow cure cutback asphalts do not emit as much VOC as suitable replacement emulsions do

. Furthermore, staff’s revi ew of the rules adopted by other states that call for seasonal restrictions on cutback asphalt have exemptions where cutback asphalt is needed within the ozone season , negating the benefits of the ir rule

. Therefore, staff is recommending no changes to Rul e 1108. Rule 1108 i s a highly e ffective rule, as is Rule 1108.1 , because both rules in tandem act to disallow the much more evaporative “rapid” and “medium” cutback asphalts and to replace them with lower emitting rapid and medium curing emulsi fied asphalts , and non

-volatile slow cure cutback asphalts.**Technology Assessment for Rule 1108** 

**– Cutback Asphalt** 

R
- 1 **REFERENCES** 1. ASTM D
- 2399, Standard Practice for Selection of Cutback Asphalts, Reapproved 2005. 2. ASTM D3628, Standard Practice for Selection and Use of Emulsified Asphalts , 2008 3. U.S. EPA AP
- 42 , Volume 1, Chapter 4.5, July 1979
. 4. Energy

Information Administration, State Energy Data System, Table F8 , 2005
. 5. Sonoma Technology Inc, Report on Asphalt Paving and Roofing , Attachment C, 2001
. 6. U.S. EPA, Control of Volatile Organic Compounds from use of Cutback Asphalt , EPA
- 450/2

- 77
- 037
. 7. Emultec.com 8. Western Emulsions, Inc., Presentation Materials, An Introduction to Warm Mix Asphalt , 2007
**KEY CONTACTS** Los Angeles County

Public Works San Bernardino Transportation Department Paramount Petroleum Corp Asphalt Emulsion Manufacturers Association Sully

- Miller Contracting Company Justice & Associates Asphalt Pavement Association of California**Technology Assessment for Rule 1108** 

**– Cutback Asphalt** 

A
- 1 **APPENDIX A**

**– EXAMPLE RULE CONTAIN**  **ING SEASONAL EXEMPTI ON**