Faq Asphalt
Content
Q: A:
Is Midwest Sealcoat Licensed, Bonded and Insured? Yes to all all of the above and and very important to protect all all parties.
Q: How do apply seal coat material? A: All material is applied by hand squeegee. Hand application ensures proper material penetration and protects surrounding elements from over-spray where spraying applicat ions are used. Q: A:
What seal coating material do you use? Midwest Sealcoat uses uses both Sakrete Amguard Amguard S-250 coal tar and SealMaster coal tar.
Q: Will any seal coating material material get on my garage, brick pavers or other surrounding surrounding elements? A: Careful hand application ensures ensures that seal coat material material will only be applied to your your asphalt. Q: When should a new driveway be sealed for for the first time? A: New driveways driveways can be sealed 90 days after construction construction ± This allows any oils to dissipate from surface so there are bonding issues. Q: What time of year do you recommend seal coating? A: The seal seal coating season season is generally May through October ± Any time during during the season is is optimal for for seal coating. Autumn has been inaccurately inaccurately consider the best time to seal. As a matter of fact, waiting for fall is not optimal o ptimal because so many seal coating co mpanies are completely booked. Q: How long should I stay off my driveway after it it is sealed? A: Under most most conditions, conditions, a driveway may be walked on after and hour hour and a vehicle vehicle may may drive on it after 24 hours.
Q: Do you price match with cheaper competitors? A: Most often not. Remember, you get what you pay for. Midwest Sealcoat has been in in business for for 20 years offering the utmost in professional service. service. We will not not compete with companies using inferior product or services. Q: What are the terms of payment? A: Residential customers pay for seal coating upon completion of work. Commercial customers are required to make a 30% down payment with the balance being due upon completion of work. Q: How often should my parking lot be striped? A: The general rule is is every other year year after seal coating. However, depending on corrosive material exposure or heavy traffic, new striping and signage may be required yearly ± especially e specially fire lanes, stop bars and cross walks. Q: When is the best time to stripe stripe or paint signage? A: Striping and signage should only be painted during times where the temperature is is greater than 40 degrees Fahrenheit. Q: How long does it it take for for striping striping and signage signage to dry? A: Under normally dry conditions, conditions, cars and foot foot traffic traffic are safe to travel over painted surfaces within 15 to 30 minutes. minutes. Q: Do I have to include Handicap and other markings? A: Yes, you must must include include all signage required by the municipal municipal or governing governing code. Midwest Sealcoat will assist in determining the appropriate/legal striping and signage. Q: Is Midwest Sealcoat Licensed, Bonded and a nd Insured? A: Yes to all of the above and very important to protect all parties.
ASPHALT FOR AIRPORTS QUESTIONS AND ANSWERS Q. Can asphalt be used to pave the runways at airports? A. Yes. In fact, only asphalt can provide a super-smooth, durable surface that can be maintained during off-peak hours and returned to service quickly. Q. At big commercial airports, is asphalt tough enough to take the punishment of heavy planes? A. Yes. Just ask the people who operate some of the b usiest airports in the country. Some of the commercial airports with asphalt runways include Baltimore-Washington International, Lindbergh Field in San Diego, McCarren International (Las Vegas), Memphis International, Newark International, Oakland International, O'Hare International (Chicago), and San Francisco International. Q. Is the surface of an asphalt pavement good for landing planes? A. Certainly. An asphalt pavement surface can be designed and constructed to increase skid resistance, lower the risk of hydroplaning, or decrease splash and
In that sense, the needs of both are the same. On the other hand, asphalt pavements can be customized to the exact requirements of the particular airport. Q. What happens when an airport shuts down a runway for maintenance? A. With asphalt, it may not be necessary. Just as asphalt roads can be rehabilitated during off-peak hours, so can airport runways. Q. How much does smoothness matter at an airport? A. A lot! The smoother a pavement is, the longer it will last. And, with a smoother surface, takeoffs and landings are both safer and more comfortable. Q. Can Perpetual Pavements be used for airport runways? A. The Perpetual Pavement principle a pavement whose structure lasts indefinitely, with a surface that can be renewed at infrequent intervals works very well for airports. The concept has already been proved at the Baltim oreWashington International Airport in Maryland and Eareckson Air Force Base in Alaska, both of which were recognized r ecognized with Perpetual Pavement Awards in 2002. Q. Can you give examples of how HMA has been used for airport runway
with a computerized grade control to place a 4-inch overlay, and corrected an average of 25 i nches per mile of deviation to 2 inches per mi le. · Example: Two 7,500-foot-long runways at the Marine Air Corps Station, Cherry Point, North Carolina, Caroli na, needed paving. The Marine Air Corps asked the contractor to minimize transverse joints on the surface, so the contractor built the runways with no joints wha tsoever.
Answers to common questions: y y
y
y
y
y
y y
You may walk on new asphalt immediately, but try to keep any vehicles off for at least 24 hours. Avoid turning car wheels or spinning out for at least 7 days to avoid scarring and indentations in the new asphalt. Most scuffing will disappear over time and use of the new asphalt. It is normal for loose gravel or sand to be present at joints or tight areas for the first month or until rain washes it away. In tight areas where the asphalt was hand applied and compacted there may appear a different texture, this will not affect the durability of the asphalt. Small puddles of water may lay on the new asphalt despite every effort to avoid this due to natural slope and drainage. It is recommended to back fill the edges of a new driveway with soil approximately one inch from the top to allow for proper drainage and grass growth. The edges are the weakest part due to lack of side support. Avoid driving off the edges to prevent cracking or crumbling. Asphalt sealcoating is a product that is applied to cured asphalt to extend its service life. Seal Coating is recommended approximately six months after paving to protect the new asphalt from
less than about 250 degrees. It therefore needs to be produced relatively close to where it is needed. This is why hot-mix asphalt is produced at thousands of small facil ities near residential centers and roadways, rather than at a few large facilities at distant locations. Q. Have hot mix asphalt plants been tested with regard to airborne emissions? A. Yes. The U.S. Environmental Protection Agency (EPA) has extensively tested, or overseen the testing of, hot mix asphalt production. (See http://www.epa.gov/ttn/chief/ap42/ch11/related/c11s01.html and associated links, especially the Emission Assessment Report at http://www.epa.gov/ttn/chief/ap42/ch11/related/ea-report.pdf). Q. On the basis of testing, what has the U.S. EPA concluded? A. U.S. EPA has concluded that even the largest hot mix asphalt plants, provided they are equipped with standard air pollution control equipment, are not major sources of pollution. This is in contrast to almost 200 other types of manufacturing facilities, which are considered, per the federal Clean Air Act, to be major sources of potentially hazardous air pollutants. (See Federal Register: February 12, 2002, Volume 67, Number 29, Pages 6521-6536, National Emission Standards for Hazardous Air Pollutants: Revision of Source Category List
58 Charles Street Cambridge, Massachusetts 02141 617-225-0810 FAX: 617-225-0813 [email protected] permitting of asphalt plants, finding that properly con trolled facilities do not degrade air quality or otherwise endanger public health. NCDENR has studied asphalt plants more than any other state agency, and assesses their impacts using methods similar to those used by South Carolina DEHC. Q. What compounds are emitted to the air from hot mix asphalt plant exhaust stacks? A. The gases expected to exit the exhaust stack of the proposed facility are listed below in the table. As shown, more than 99% of the exhaust gases are made up of four chemicals nitrogen, water vapor, oxygen, and carbon dioxide. Emissions of these four chemicals, at these rates, are not expected to affect public health. Table. Typical concentrations of compounds in gases emitted by hot-mix asphalt facilities. Compound Concentration in stack gas Nitrogen 67.7 % Water 20.0 %
dioxide, nitrogen oxides, and some members of a group of chemicals known as volatile organic compounds (VOCs, such as formal dehyde and benzene) can harm health. These pollutants, which are products of incomplete combustion, are emitted by cars and trucks, electric power plants, cigarettes, and many other sources. Cambridge Environmental Inc 58 Charles Street Cambridge, Massachusetts 02141 617-225-0810 FAX: 617-225-0813 [email protected] 3 Q. Will children or others at the New Heights Middle School in Jefferson be endangered if the proposed hot mix asphalt plant is built? A. No. The proposed asphalt plant will, of course, emit pollutants, but not at dangerous levels. For example, the proposed plant would emit benzene, but this benzene will represent only 0.2% of the benzene already in outdoor air at the School (and throughout the County) due to cars, trucks, and other ordinary sources of this pollutant. Similarly, the proposed plant would add some formaldehyde to local outdoor air, but this increment
Public concerns in the late 1990's prompted U.S. EPA to conduct a comprehensive study in which two hot mix asphalt plants (one in California and one in Massachusetts) were tested extensively for fugitive emissions and stack emissions. The EPA found that fugitive emissions of volatile substances were small, relative to exhaust stack emissions. (See EPAs 2000 Hot Mix Asphalt Plants Emission Assessment Report at http://www.epa.gov/ttn/chief/ap42/ch11/related/ea-report.pdf). Cambridge Environmental Inc 58 Charles Street Cambridge, Massachusetts 02141 617-225-0810 FAX: 617-225-0813 [email protected] 4 Q. Are emissions from hot mix asphalt plants harmful to worker health? A. With regard to worker health and safety, although roofers who work with roofing asphalts (which are quite different, chemically and physically, from paving asphalts) and who remove coal-tar based products may be at some excess risk of some respiratory disease, people working with paving asphalt do not seem to be at excess risk. Watkins and
has used hot mix asphalt to line its drinking water reservoirs. Many fish hatchery ponds in Oregon and Washington are lined with hot mix asphalt. Q. Overall, then, are emissions from modern hot mix asphalt plants hazardous to public health? A. No: although some of the chemical compounds emitted by asphalt plants can be hazardous if people are exposed to high enough levels, the am ounts of these compounds emitted from these plants (and from associated operations, such as l oading the product onto trucks) are too small to affect public health. Hot mix asphalt production facilities are not major sources of air pollution per U.S. EPA. Air quality modeling of emissions from modern hot mix asphalt facilities almost always shows that impacts are very small, even for the nearest neighbors to a site, let alone for those farther afield. Odors can and should be controlled to acceptable levels, as should dust and traffic from such operations. Experience with thousands of currently operating hot mix asphalt plants in the nation indicates that they can be designed and operated in manners consistent with maintenance
$XXX left for paving the drive. What can you do for that m uch? Of course that amount is usually less
than what is actually needed to do a proper job. Many times premature structural failures in driveways are caused by this scenario or in older homes perhaps the previous owner was only concerned about low price, not high quality, if they had the drive replaced. Unfortunately its often impossible to tell how well the driveway was constructed after the fact. One tip would be if a new home driveway was not guaranteed against any structural defects for at least 2 years, or if there are areas that look rough or that hold water. The second part of this is properly maintained. If asphalt pavements didnt need maintenance your city street department would be out of a job as would thousands of pavement maintenance contractors. As we get to answers to some more common questions proper maintenance will become self-explanatory. Why should I sealcoat my driveway? Asphalt pavements are made up of stone (agg regate) fine stone or sand, and asphalt cement. The asphalt cement is what gives the pavement its black appearance and is the glue that holds everything together. Often I joking answer this question in person by asking why do you paint the wood on your house? Its obvious of course; to preserve the wood and protect it from damage from the elements. The same is true of asphalt pavements. Have you noticed that new asphalt is jet black but soon begins to fade and in a year or two has turned gray? Thats oxidation. The effects of the sun and rain/snow oxidizing the asphalt cement in the pavement. Gi ven enough time the pavement becomes brittle and has less resistance to the loads placed on it. This can lead to a multitude of problems. Asphalt is a petroleum product so any other petroleum derivatives that contact it will dissolve into the asphalt, weakening or dissolving the asphalts glue like properties. These substances commonly include motor oil, transmission/power steering/ or brake fluids, gasoline, and perhaps household solvents like some cleaners. Its common to see asphalt damaged by concrete cleaning products used on a sidewalk but
crack sealant materials. Left alone cracks allow moisture to penetrate the asphalt surface. Water expands as it freezes, so moisture in the cracks does the greatest damage in the winter months. But before you breathe a sigh of relief because you live in a warm area, moisture penetration does great damage to pavement no matter what the temperature. It just does more damage faster in freezing conditions. Homeowner grade crack sealants are always cold applied and must dry. (Contractors use a superior method with hot-applied materials that set as soon as they cool). The main i ssue in sealing cracks is that they MUST be clean, dry, and have no vegetation present prior to any sealing. Homeowners should always shop for a sealant containing the highest possible amount of rubber. The rubber allows the sealant to expand and contract with the pavement. Cheaper crack fillers are hard when cured and as the pavement moves they will separate from the asphalt, and allow moisture to penetrate again. What about these ugly stains? Be careful. One way to prevent stains is to sealcoat the pavement in the first place, but depending on the type of stain the cure can be more damaging than the illness. Be careful to read the label of any driveway cleaning product. Many contain solvents. ANY solvent will damag e the asphalt pavement and should be avoided, even if the product says its for driveways. Often for oily stains the best approach is a biodegradable cleaner (like Simple Green or similar), if those are not readily available plain dishwashing soap will do. Mix a soapy water solution, apply to the stain and let stand for a few minutes, then get a good scrub brush and apply a liberal amount of elbow grease and rinse thoroughly. Take note if the scrub brush begins to loosen stones in the asphalt. If this happens, stop and rinse. That is an indication that whatever stained the drive has al ready weakened the asphalt and you could cause more damage trying to remove it. Contractors have a variety of products made for priming stains before applying sealcoating, however these may not be available to home owners and depending on the type
Normally, the above guidelines would be applied to both new an d existing pavements. If a warranty was a pplied to a project, a more conservative approach - such as the use of blending charts - might be taken. It is suggested that you contact the local stat e highway agency and/or asphalt binder supplier for the prevailing l ocal practices. Top
Contents
PLACEMENT Q.
Should construction crews be allowed to pave in the rain?
A.
This common question can mean different things to different people because of the wide range of precipitation encompassed by the word ³rain.´ On one end, occasional light sprinkles should not be cause to shut down operations. However, a steady downpour, either light or h eavy, should result in cessation of paving activities. To avoid waste, so me states have verbiage in their s pecifications stating that trucks in route to the project when rain begins can be laid a t the contractor's risk. Also keep in mind that the surface on which you are paving may in fluence your decision. Paving on a firm, stable, well-draining crushed aggregate base might be given more leeway than a thin asphalt overlay. Raining or not, new pavement must be placed on a firm, unyielding base. Critical ideas to keep in mind when dealing with rain:
y
rain will cool the asphalt mix and could make obtaining proper compaction more difficult
y
the asphalt lifts must be able to properly bond together and moisture can be a hindrance to that bond
y
puddles overlaid with HMA turn to steam, which ma y cause stripping (separation of the asphalt binder from the aggregate) - never pave over puddles whether it is raining or not
If you temporarily suspend paving operations due to rain, don't forget to:
y
keep all trucks tarped
y
construct a vertical-faced construction joint
y
properly dispose of all material left in the hopper
y
be careful not to track mud and dirt onto the project
Asphalt pavements are designed to last for many years, so don't l et a sense of urgency to get the job done quickly al low you to make decisions which could strip years away from the pavement li fe. Q.
Does AI have any recommendations of an a sphaltic concrete sealer?
A.
Information on fuel-resistant asphalt sealers can be found at www.aaptp.us with Report 05-02.
Q.
How do I determine how much asphalt is required for a project?
A.
Here's the process:
y
World's Strongest Intersection
Top
Contents
WEATHER Q. A.
Should construction crews be allowed to pave in the rain? This common question can mean different things to different people because of the wide range of precipitation encompassed by the word ³rain.´ On one end, occasional light sprinkles should not be cause to shut down operations. However, a steady downpour, either light or heavy, should result in cessation of paving activities. To avoid waste, some states have verbiage in their specifications stating that trucks in route to the project when rain begins can be l aid at the contractor's risk. Also keep in mind that the surface on which you are paving may in fluence your decision. Paving on a firm, stable, well-draining crushed aggregate base might be given more leeway than a thin asphalt overlay. Raining or n ot, new pavement must be placed on a firm, u nyielding base. Critical ideas to keep in mind when dealing with rain:
y
rain will cool the asphalt mix and could make obtaining proper compaction more difficult
y
the asphalt lifts must be able to properly bond together and moisture can be a hindrance to that bond
y
puddles overlaid with HMA turn to steam, which ma y cause stripping (separation of the asphalt binder from the aggregate) - never pave over puddles whether it is raining or not
If you temporarily suspend paving operations due to rain, don't forget to:
y
keep all trucks tarped
y
construct a vertical-faced construction joint
y
properly dispose of all material left in the hopper
y
be careful not to track mud and dirt onto the project
Asphalt pavements are designed to last for many years, so don't let a sense of urgency to get the job done quickly al low you to make decisions which could strip years away from the pavement li fe. Q.
Can asphalt be applied in the rai n (light drizzle)?
A.
It is not avisable to start paving if it is raini ng. If rain starts after paving has begun, the work can continue as long as there is no standing water and the rain i s not too hard. The primary concern is achieving adequate compaction, as the mix will cool much faster due to evaporative cooling if laid on a wet surface or rain falls on an uncompacted mat. Additional compactive effort will be needed and monitoring temperatures is key to acheiving adequate density. Top
Contents
DE-ICING CHEMICALS Q.
Do de-icing salts or calcium magnesium acetate (CMA) ha ve a detrimental affect on asphalt?
Is Midwest Sealcoat Licensed, Bonded and Insured? Yes to all all of the above and and very important to protect all all parties.
Q: How do apply seal coat material? A: All material is applied by hand squeegee. Hand application ensures proper material penetration and protects surrounding elements from over-spray where spraying applicat ions are used. Q: A:
What seal coating material do you use? Midwest Sealcoat uses uses both Sakrete Amguard Amguard S-250 coal tar and SealMaster coal tar.
Q: Will any seal coating material material get on my garage, brick pavers or other surrounding surrounding elements? A: Careful hand application ensures ensures that seal coat material material will only be applied to your your asphalt. Q: When should a new driveway be sealed for for the first time? A: New driveways driveways can be sealed 90 days after construction construction ± This allows any oils to dissipate from surface so there are bonding issues. Q: What time of year do you recommend seal coating? A: The seal seal coating season season is generally May through October ± Any time during during the season is is optimal for for seal coating. Autumn has been inaccurately inaccurately consider the best time to seal. As a matter of fact, waiting for fall is not optimal o ptimal because so many seal coating co mpanies are completely booked. Q: How long should I stay off my driveway after it it is sealed? A: Under most most conditions, conditions, a driveway may be walked on after and hour hour and a vehicle vehicle may may drive on it after 24 hours.
Q: Do you price match with cheaper competitors? A: Most often not. Remember, you get what you pay for. Midwest Sealcoat has been in in business for for 20 years offering the utmost in professional service. service. We will not not compete with companies using inferior product or services. Q: What are the terms of payment? A: Residential customers pay for seal coating upon completion of work. Commercial customers are required to make a 30% down payment with the balance being due upon completion of work. Q: How often should my parking lot be striped? A: The general rule is is every other year year after seal coating. However, depending on corrosive material exposure or heavy traffic, new striping and signage may be required yearly ± especially e specially fire lanes, stop bars and cross walks. Q: When is the best time to stripe stripe or paint signage? A: Striping and signage should only be painted during times where the temperature is is greater than 40 degrees Fahrenheit. Q: How long does it it take for for striping striping and signage signage to dry? A: Under normally dry conditions, conditions, cars and foot foot traffic traffic are safe to travel over painted surfaces within 15 to 30 minutes. minutes. Q: Do I have to include Handicap and other markings? A: Yes, you must must include include all signage required by the municipal municipal or governing governing code. Midwest Sealcoat will assist in determining the appropriate/legal striping and signage. Q: Is Midwest Sealcoat Licensed, Bonded and a nd Insured? A: Yes to all of the above and very important to protect all parties.
ASPHALT FOR AIRPORTS QUESTIONS AND ANSWERS Q. Can asphalt be used to pave the runways at airports? A. Yes. In fact, only asphalt can provide a super-smooth, durable surface that can be maintained during off-peak hours and returned to service quickly. Q. At big commercial airports, is asphalt tough enough to take the punishment of heavy planes? A. Yes. Just ask the people who operate some of the b usiest airports in the country. Some of the commercial airports with asphalt runways include Baltimore-Washington International, Lindbergh Field in San Diego, McCarren International (Las Vegas), Memphis International, Newark International, Oakland International, O'Hare International (Chicago), and San Francisco International. Q. Is the surface of an asphalt pavement good for landing planes? A. Certainly. An asphalt pavement surface can be designed and constructed to increase skid resistance, lower the risk of hydroplaning, or decrease splash and
In that sense, the needs of both are the same. On the other hand, asphalt pavements can be customized to the exact requirements of the particular airport. Q. What happens when an airport shuts down a runway for maintenance? A. With asphalt, it may not be necessary. Just as asphalt roads can be rehabilitated during off-peak hours, so can airport runways. Q. How much does smoothness matter at an airport? A. A lot! The smoother a pavement is, the longer it will last. And, with a smoother surface, takeoffs and landings are both safer and more comfortable. Q. Can Perpetual Pavements be used for airport runways? A. The Perpetual Pavement principle a pavement whose structure lasts indefinitely, with a surface that can be renewed at infrequent intervals works very well for airports. The concept has already been proved at the Baltim oreWashington International Airport in Maryland and Eareckson Air Force Base in Alaska, both of which were recognized r ecognized with Perpetual Pavement Awards in 2002. Q. Can you give examples of how HMA has been used for airport runway
with a computerized grade control to place a 4-inch overlay, and corrected an average of 25 i nches per mile of deviation to 2 inches per mi le. · Example: Two 7,500-foot-long runways at the Marine Air Corps Station, Cherry Point, North Carolina, Caroli na, needed paving. The Marine Air Corps asked the contractor to minimize transverse joints on the surface, so the contractor built the runways with no joints wha tsoever.
Answers to common questions: y y
y
y
y
y
y y
You may walk on new asphalt immediately, but try to keep any vehicles off for at least 24 hours. Avoid turning car wheels or spinning out for at least 7 days to avoid scarring and indentations in the new asphalt. Most scuffing will disappear over time and use of the new asphalt. It is normal for loose gravel or sand to be present at joints or tight areas for the first month or until rain washes it away. In tight areas where the asphalt was hand applied and compacted there may appear a different texture, this will not affect the durability of the asphalt. Small puddles of water may lay on the new asphalt despite every effort to avoid this due to natural slope and drainage. It is recommended to back fill the edges of a new driveway with soil approximately one inch from the top to allow for proper drainage and grass growth. The edges are the weakest part due to lack of side support. Avoid driving off the edges to prevent cracking or crumbling. Asphalt sealcoating is a product that is applied to cured asphalt to extend its service life. Seal Coating is recommended approximately six months after paving to protect the new asphalt from
less than about 250 degrees. It therefore needs to be produced relatively close to where it is needed. This is why hot-mix asphalt is produced at thousands of small facil ities near residential centers and roadways, rather than at a few large facilities at distant locations. Q. Have hot mix asphalt plants been tested with regard to airborne emissions? A. Yes. The U.S. Environmental Protection Agency (EPA) has extensively tested, or overseen the testing of, hot mix asphalt production. (See http://www.epa.gov/ttn/chief/ap42/ch11/related/c11s01.html and associated links, especially the Emission Assessment Report at http://www.epa.gov/ttn/chief/ap42/ch11/related/ea-report.pdf). Q. On the basis of testing, what has the U.S. EPA concluded? A. U.S. EPA has concluded that even the largest hot mix asphalt plants, provided they are equipped with standard air pollution control equipment, are not major sources of pollution. This is in contrast to almost 200 other types of manufacturing facilities, which are considered, per the federal Clean Air Act, to be major sources of potentially hazardous air pollutants. (See Federal Register: February 12, 2002, Volume 67, Number 29, Pages 6521-6536, National Emission Standards for Hazardous Air Pollutants: Revision of Source Category List
58 Charles Street Cambridge, Massachusetts 02141 617-225-0810 FAX: 617-225-0813 [email protected] permitting of asphalt plants, finding that properly con trolled facilities do not degrade air quality or otherwise endanger public health. NCDENR has studied asphalt plants more than any other state agency, and assesses their impacts using methods similar to those used by South Carolina DEHC. Q. What compounds are emitted to the air from hot mix asphalt plant exhaust stacks? A. The gases expected to exit the exhaust stack of the proposed facility are listed below in the table. As shown, more than 99% of the exhaust gases are made up of four chemicals nitrogen, water vapor, oxygen, and carbon dioxide. Emissions of these four chemicals, at these rates, are not expected to affect public health. Table. Typical concentrations of compounds in gases emitted by hot-mix asphalt facilities. Compound Concentration in stack gas Nitrogen 67.7 % Water 20.0 %
dioxide, nitrogen oxides, and some members of a group of chemicals known as volatile organic compounds (VOCs, such as formal dehyde and benzene) can harm health. These pollutants, which are products of incomplete combustion, are emitted by cars and trucks, electric power plants, cigarettes, and many other sources. Cambridge Environmental Inc 58 Charles Street Cambridge, Massachusetts 02141 617-225-0810 FAX: 617-225-0813 [email protected] 3 Q. Will children or others at the New Heights Middle School in Jefferson be endangered if the proposed hot mix asphalt plant is built? A. No. The proposed asphalt plant will, of course, emit pollutants, but not at dangerous levels. For example, the proposed plant would emit benzene, but this benzene will represent only 0.2% of the benzene already in outdoor air at the School (and throughout the County) due to cars, trucks, and other ordinary sources of this pollutant. Similarly, the proposed plant would add some formaldehyde to local outdoor air, but this increment
Public concerns in the late 1990's prompted U.S. EPA to conduct a comprehensive study in which two hot mix asphalt plants (one in California and one in Massachusetts) were tested extensively for fugitive emissions and stack emissions. The EPA found that fugitive emissions of volatile substances were small, relative to exhaust stack emissions. (See EPAs 2000 Hot Mix Asphalt Plants Emission Assessment Report at http://www.epa.gov/ttn/chief/ap42/ch11/related/ea-report.pdf). Cambridge Environmental Inc 58 Charles Street Cambridge, Massachusetts 02141 617-225-0810 FAX: 617-225-0813 [email protected] 4 Q. Are emissions from hot mix asphalt plants harmful to worker health? A. With regard to worker health and safety, although roofers who work with roofing asphalts (which are quite different, chemically and physically, from paving asphalts) and who remove coal-tar based products may be at some excess risk of some respiratory disease, people working with paving asphalt do not seem to be at excess risk. Watkins and
has used hot mix asphalt to line its drinking water reservoirs. Many fish hatchery ponds in Oregon and Washington are lined with hot mix asphalt. Q. Overall, then, are emissions from modern hot mix asphalt plants hazardous to public health? A. No: although some of the chemical compounds emitted by asphalt plants can be hazardous if people are exposed to high enough levels, the am ounts of these compounds emitted from these plants (and from associated operations, such as l oading the product onto trucks) are too small to affect public health. Hot mix asphalt production facilities are not major sources of air pollution per U.S. EPA. Air quality modeling of emissions from modern hot mix asphalt facilities almost always shows that impacts are very small, even for the nearest neighbors to a site, let alone for those farther afield. Odors can and should be controlled to acceptable levels, as should dust and traffic from such operations. Experience with thousands of currently operating hot mix asphalt plants in the nation indicates that they can be designed and operated in manners consistent with maintenance
$XXX left for paving the drive. What can you do for that m uch? Of course that amount is usually less
than what is actually needed to do a proper job. Many times premature structural failures in driveways are caused by this scenario or in older homes perhaps the previous owner was only concerned about low price, not high quality, if they had the drive replaced. Unfortunately its often impossible to tell how well the driveway was constructed after the fact. One tip would be if a new home driveway was not guaranteed against any structural defects for at least 2 years, or if there are areas that look rough or that hold water. The second part of this is properly maintained. If asphalt pavements didnt need maintenance your city street department would be out of a job as would thousands of pavement maintenance contractors. As we get to answers to some more common questions proper maintenance will become self-explanatory. Why should I sealcoat my driveway? Asphalt pavements are made up of stone (agg regate) fine stone or sand, and asphalt cement. The asphalt cement is what gives the pavement its black appearance and is the glue that holds everything together. Often I joking answer this question in person by asking why do you paint the wood on your house? Its obvious of course; to preserve the wood and protect it from damage from the elements. The same is true of asphalt pavements. Have you noticed that new asphalt is jet black but soon begins to fade and in a year or two has turned gray? Thats oxidation. The effects of the sun and rain/snow oxidizing the asphalt cement in the pavement. Gi ven enough time the pavement becomes brittle and has less resistance to the loads placed on it. This can lead to a multitude of problems. Asphalt is a petroleum product so any other petroleum derivatives that contact it will dissolve into the asphalt, weakening or dissolving the asphalts glue like properties. These substances commonly include motor oil, transmission/power steering/ or brake fluids, gasoline, and perhaps household solvents like some cleaners. Its common to see asphalt damaged by concrete cleaning products used on a sidewalk but
crack sealant materials. Left alone cracks allow moisture to penetrate the asphalt surface. Water expands as it freezes, so moisture in the cracks does the greatest damage in the winter months. But before you breathe a sigh of relief because you live in a warm area, moisture penetration does great damage to pavement no matter what the temperature. It just does more damage faster in freezing conditions. Homeowner grade crack sealants are always cold applied and must dry. (Contractors use a superior method with hot-applied materials that set as soon as they cool). The main i ssue in sealing cracks is that they MUST be clean, dry, and have no vegetation present prior to any sealing. Homeowners should always shop for a sealant containing the highest possible amount of rubber. The rubber allows the sealant to expand and contract with the pavement. Cheaper crack fillers are hard when cured and as the pavement moves they will separate from the asphalt, and allow moisture to penetrate again. What about these ugly stains? Be careful. One way to prevent stains is to sealcoat the pavement in the first place, but depending on the type of stain the cure can be more damaging than the illness. Be careful to read the label of any driveway cleaning product. Many contain solvents. ANY solvent will damag e the asphalt pavement and should be avoided, even if the product says its for driveways. Often for oily stains the best approach is a biodegradable cleaner (like Simple Green or similar), if those are not readily available plain dishwashing soap will do. Mix a soapy water solution, apply to the stain and let stand for a few minutes, then get a good scrub brush and apply a liberal amount of elbow grease and rinse thoroughly. Take note if the scrub brush begins to loosen stones in the asphalt. If this happens, stop and rinse. That is an indication that whatever stained the drive has al ready weakened the asphalt and you could cause more damage trying to remove it. Contractors have a variety of products made for priming stains before applying sealcoating, however these may not be available to home owners and depending on the type
Normally, the above guidelines would be applied to both new an d existing pavements. If a warranty was a pplied to a project, a more conservative approach - such as the use of blending charts - might be taken. It is suggested that you contact the local stat e highway agency and/or asphalt binder supplier for the prevailing l ocal practices. Top
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PLACEMENT Q.
Should construction crews be allowed to pave in the rain?
A.
This common question can mean different things to different people because of the wide range of precipitation encompassed by the word ³rain.´ On one end, occasional light sprinkles should not be cause to shut down operations. However, a steady downpour, either light or h eavy, should result in cessation of paving activities. To avoid waste, so me states have verbiage in their s pecifications stating that trucks in route to the project when rain begins can be laid a t the contractor's risk. Also keep in mind that the surface on which you are paving may in fluence your decision. Paving on a firm, stable, well-draining crushed aggregate base might be given more leeway than a thin asphalt overlay. Raining or not, new pavement must be placed on a firm, unyielding base. Critical ideas to keep in mind when dealing with rain:
y
rain will cool the asphalt mix and could make obtaining proper compaction more difficult
y
the asphalt lifts must be able to properly bond together and moisture can be a hindrance to that bond
y
puddles overlaid with HMA turn to steam, which ma y cause stripping (separation of the asphalt binder from the aggregate) - never pave over puddles whether it is raining or not
If you temporarily suspend paving operations due to rain, don't forget to:
y
keep all trucks tarped
y
construct a vertical-faced construction joint
y
properly dispose of all material left in the hopper
y
be careful not to track mud and dirt onto the project
Asphalt pavements are designed to last for many years, so don't l et a sense of urgency to get the job done quickly al low you to make decisions which could strip years away from the pavement li fe. Q.
Does AI have any recommendations of an a sphaltic concrete sealer?
A.
Information on fuel-resistant asphalt sealers can be found at www.aaptp.us with Report 05-02.
Q.
How do I determine how much asphalt is required for a project?
A.
Here's the process:
y
World's Strongest Intersection
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Contents
WEATHER Q. A.
Should construction crews be allowed to pave in the rain? This common question can mean different things to different people because of the wide range of precipitation encompassed by the word ³rain.´ On one end, occasional light sprinkles should not be cause to shut down operations. However, a steady downpour, either light or heavy, should result in cessation of paving activities. To avoid waste, some states have verbiage in their specifications stating that trucks in route to the project when rain begins can be l aid at the contractor's risk. Also keep in mind that the surface on which you are paving may in fluence your decision. Paving on a firm, stable, well-draining crushed aggregate base might be given more leeway than a thin asphalt overlay. Raining or n ot, new pavement must be placed on a firm, u nyielding base. Critical ideas to keep in mind when dealing with rain:
y
rain will cool the asphalt mix and could make obtaining proper compaction more difficult
y
the asphalt lifts must be able to properly bond together and moisture can be a hindrance to that bond
y
puddles overlaid with HMA turn to steam, which ma y cause stripping (separation of the asphalt binder from the aggregate) - never pave over puddles whether it is raining or not
If you temporarily suspend paving operations due to rain, don't forget to:
y
keep all trucks tarped
y
construct a vertical-faced construction joint
y
properly dispose of all material left in the hopper
y
be careful not to track mud and dirt onto the project
Asphalt pavements are designed to last for many years, so don't let a sense of urgency to get the job done quickly al low you to make decisions which could strip years away from the pavement li fe. Q.
Can asphalt be applied in the rai n (light drizzle)?
A.
It is not avisable to start paving if it is raini ng. If rain starts after paving has begun, the work can continue as long as there is no standing water and the rain i s not too hard. The primary concern is achieving adequate compaction, as the mix will cool much faster due to evaporative cooling if laid on a wet surface or rain falls on an uncompacted mat. Additional compactive effort will be needed and monitoring temperatures is key to acheiving adequate density. Top
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DE-ICING CHEMICALS Q.
Do de-icing salts or calcium magnesium acetate (CMA) ha ve a detrimental affect on asphalt?
