Episode XIII Rational criteria for choosing asphalt joint heaters.

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Episode XIII   Rational criteria for choosing asphalt joint heaters.

All cold joint heating efforts are to be lauded as they are a big step in preventing premature pavement failure. Dedicated asphalt joint heaters need to be integrated into asphalt construction specifications and for that to happen in the real world, the process must easily and inexpensively blend into current road building methodology. Cold joint heaters must be invisible in the paving production chain and the controls must be automated to limit human intervention.  The process has already show excellent results in all climates and pavement types around the world. If the process is to gain in popularity across the industry and become fully integrated into contract specifications, asphalt cold joint heater choice must consider certain criteria:

1-     Heaters should be paver mounted. Tow vehicles are costly and should be avoided.

2-     All steel construction is preferred, fragile ceramics or easily damaged glass mats are to be avoided.

3-     Large multi-section heaters require large haul trailers as well as labour intensive job site assembly.

4-     All steel infrared burners will provide maximum heat with minimum fuel consumption.

5-     Automated controls should limit human intervention and be fully integrated to the paver.

6-     Paver mounting should be left or right, simple and quick and adaptable to all paver brands.

7-     Design should be lightweight, offer trouble free service, reliability and long life.

8-     Safety protocols should govern fuel types and capacities, component choice and build quality.

9-      Safe propane vapour in 100# cylinders is preferred by most construction crews.

10-  Heat controls should be interfaced to paver motion controls.

11- Crew safety should be considered first in all aspects of machine engineering.

The more of these criteria met by an asphalt joint heater, the more effectively and quickly they will become standard equipment on paving jobs. Cold joint heaters are without a doubt one of the most cost effective tools in quality road construction and maintenance. But even if you have never set foot on a hot mat, give some thought not only to cost and performance, but also to crew safety and simple work methodology. Be critical of machines which fall short of full integration or safe implementation. There is no need to settle for unsafe or inefficient units, cold joint heaters are available which will meet all the above criteria.

 

In Episode XIV we will continue our examination of cold joints failures in pavement and the benefits of seamless patching.

 

 

Episode XII Asphalt joint heaters

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Episode XII     Asphalt joint heaters

As we have seen, most asphalt failures begin with a single crack. Often this crack originates in an unintentionally built in weak point on new paving jobs when a major crack develops along the joint between adjacent mats. This weak point is called, drum roll please, the Cold Joint. As we saw in an earlier episode once it has cooled, asphalt looses all its ability to play nice with its neighbours. Hot asphalt cannot meld into cold asphalt and therefore a weak point develops along the intersection of the two mats. Attempts are made to minimise the weak spot by bevel cutting the edge and/or adding liquid adhesives and such; at best these only forestall the cold joint failure.

There is a more permanent solution: Pre-heat the cold existing mat edge so that it can be married to the new mat without leaving a weak joint.  Like most good inventions, it was born of necessity on an airport runway paving site near the arctic circle. By applying our technology, longitudinal cracks and failed tie-ins became a thing of the past;  joint compaction test failures ceased altogether. I was granted a patent for my efforts and the idea has since been copied by several manufacturers. Several companies have ‘’acknowledged’’ our designs and copied some of our older models; imitation being the sincerest form of flattery and all that. Too bad they are getting long in the tooth, they weren’t bad designs.

Since then we have gone through several models and marks and developed multiple special applications which all carry the same hallmarks of simplicity and effectiveness. Our latest production model, with its all stainless steel lightweight monocoque design and automated controls requires neither operator nor tow vehicle and is invisible in the production chain. A good asphalt joint heater should be able to maintain proper joint temperature while paving up to 35 feet per minute or more.  Cold joint heating is one of the most cost effective procedures we can use in road building. Consulting engineers and technical departments worldwide now include it in their building specifications. Does your city or state include it in theirs?

As I’ve often mentioned in other episodes, worker safety needs to be an integral part of any equipment design, not an afterthought.  Equipment operators and crews must rely heavily on the experience of the designer to insure that they are not exposed to needless risks. On gas fired equipment the use of automated valves is essential as we must be able to cut all gas flow on command. Safety shutdown controls are only one facet of the risk management. It is much safer for example, to use low-pressure (11” W.C.) propane vapour gas firing high flux infrared burners. Such a system need only have 2 high pressure hose connections. All other connections should be on the safer, low pressure side of the propane system. On one manufacturer’s heater I counted more than 35 high pressure gas line connections! This type of design borders on the reckless. When combined with moving machinery, flammable products and circumstances, it will seriously compromise worker and jobsite safety. I don’t want to be an alarmist but some of this stuff is pretty basic and yet some manufacturers seem totally unconscious. What are we to think of the rest of their product lines?

In Episode XIII   Other cold asphalt joint heaters

Episode XI A reasonable request of asphalt recyclers

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Episode XI   A reasonable request of asphalt recyclers

Like I said in an earlier episode, asphalt is one of the most recycled materials around. A lot of people and machinery are labelled asphalt recyclers. But the ultimate goal of recycling whole asphalt  without burning the asphalt cement (AC) is sought by few and attained by fewer still. There are several manufacturers who claim to master the process, but they seem to compromise heavily on heating time vs. quality of asphalt produced.

Blinded by speed they’ve lost sight of the original goal, which was to recycle 100% of the asphalt including the AC. Speed was never the most important criteria, we already know how much patch asphalt our crews can handle in a day. The first rule of environmental stewardship is REDUCE; we should not handle or recycle more material than is required. We are going to look at one of these popular recyclers in action and see if they meet any of the criteria for proper asphalt stewardship.

In my opinion, one of the worst offenders on the market is the Bagela brand. I think it is one of the most environmentally offensive pieces of machinery ever foisted on the public at any price. Watch their youtube videos, these so called recyclers are environmental nightmares.  The design is all bad but let’s start with the fuel source.  It is a kerosene fired burner heating asphalt which is rotating in a drum. Asphalt chunks are batch fed from a hopper to the drum and discharged at the opposite end through a slit in the drum (Bagela, Youtube). We already eliminated this fuel due to its inefficiency, higher emission levels, fluctuating cost and safety concerns.

Environmental mini disasters made easy: Lets look at their proposed work methodology, it is just not viable. They expect one to load the old asphalt into a dump truck, or two,  deliver it to and dump it in traffic on the street near the repair site then unload a front end loader from another truck and trailer, pick up the asphalt which has been dumped in the street and load it a bit at a time into the recycler, all this while the loader negotiates surrounding traffic. Loaded and heated, one bucket at a time until enough material has been produced for the patch. Oh and don’t forget to preheat the recycler once you get to the job because you don’t want the crew standing around waiting for asphalt any longer than they have to, do you? Mind you, all that dumping, loading and unloading will surely take a while. When in full view of the public the methodology  becomes obviously unsustainable, the manufacturer suggests that the machine’s operation be  restricted to the yard.  This doesn’t reduce pollution rather just the number of irate taxpayers. Out of sight, out of mind, as it were. This is methodology is clearly unsustainable and in my opinion the antithesis of good  environmental stewardship.

But their greatest sin are the clouds of dense blue smoke produced by force heating the asphalt. It pours out from both ends of this so called recycler.  These trailer mounted machines often escape existing clean air regulations because they are not considered permanent installations. I doubt that their operation, as is, would never be tolerated if they were considered as asphalt plants; they would surely be required to install large air filters. Bagela is allowed to pollute our air with impunity while having  the effrontery to suggest it is all for the good of our environment.

I see good environmental stewardship as follows: One should be able to arrive on the jobsite with the asphalt already heated and of sufficient quantity for the repair, immediately and without auxiliary machinery, unload the recycled hot mix and then move on to the next repair.

A two man crew working cleanly and quietly with as little impact as possible on the taxpayers health, wealth and enjoyment of their community is hardly an unattainable goal,  it happens every day. The choice is yours. This is just one man’s opinion, I could be wrong. What do you think?

Episode X The cost of recycling whole asphalt

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Episode X   The cost of recycling whole asphalt

In this episode we will look at some of the costs involved in recycling asphalt.  An important aspect of this is finding, using and supporting  existing work methods.  if we are to be successful in a quest for practical efficiency.  These can generally be broken down into the following  four categories:

1-Material cost,       2- Fuel cost,         3- Labour cost,        4- Equipment cost

1-Material cost makes whole asphalt recycling very attractive. Every city, county, state and private owner has virtually limitless supplies already paid for and in stock. When you consider that virgin hot mix can cost between $75 and $100 per ton plus the cost of hauling, and that we have tons of asphalt excavated or leftover from jobs already in stock, recycled hot-mix becomes a very attractive alternate solution. Recycling means free hot asphalt anywhere, anytime.

2-Fuel costs will be dependent on two factors: the price of the fuel and the heating efficiency of the recycling equipment. The price of the fuel is largely determined by supply and demand so we must look for fuels which generally do not compete with gasoline and diesel as their price is increasingly under pressure. Propane and Natural gas are traditionally less expensive while being readily available. They are also cleaner burning and safer to handle. According to the Propane Education  & Research council, nearly 90% of U.S. propane supplies are produced  at existing domestic facilities and another 7% comes from Canada , making propane a very secure and stable energy source.

3-Labour costs will vary from region to region and will be largely determined by pre-existing labour agreements.  Ideally, the recycling processes should  be fully automated to provide consistent and repeatable results across a varied cross-section of labourer skills. Whatever the skill level, crews are generally made up of 2 laborers on mobile bin  recyclers.  Fully automated stationary recyclers do not require dedicated operators or laborers.

4-Equipment cost will be determined by the amount of  recycled asphalt required. Small to midsized wheeled front and rear-end loaders are used for loading as they are generally readily available. The size of the recycler will determine purchase price, which for example can vary from $25K to $250K for one of our designs. The recycling equipment itself, should be ruggedly built for safety and long life. It is not unreasonable to request a 10 year warranty/service plan. The componentry should be the best available and meticulously assembled. As few moving parts as possible will assure low maintenance and gas vapour fired radiant heaters will make the most efficient use of fuel.

Pay careful attention to these four elements and also remember that if you pay too much for something generally all you will lose is a bit of money. On the other hand, if you don’t pay enough for something, you may lose everything.

Episode VIII Environmental advantages of recycling whole asphalt

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Episode  VIII   Environmental advantages of recycling whole asphalt

Over 80% of removed asphalt is presently classified as recycled.  But we can do a lot better for the environment because a large part of that 80% refers to the aggregates recovered and not the asphalt cement. Since asphalt cement is the main oil based component, you ain’treally  recycling unless you recycle the AC also.

Unfortunately most existing recycling methods burn off the liquid asphalt coating the aggregates and turn it into dense blue smoke, which in my opinion is a singularly bad idea. Most governing bodies agree and therefore limit the amount of recycled material which can be included in making new hot mix.

We know that methods which use the whole material and manipulate it the least in the recycling process offer the highest rewards. Just the hauling of material to a distant plant for re-processing has an enormous environmental impact; picture all those dump trucks to’ ing and fro’ ing down the highway…

I think that genuine environmental stewardship and by extension asphalt stewardship, must satisfy 3 key requirements to be successful in the real world:

1-     It must be cost effective.

2-     It must perform well.

3-     It must have minimal environmental impact.

This translates to manipulating the asphalt as little as possible, and simplifying operation and maintenance  for the end user and using automated controls firing high efficiency heaters with the cleanest fuels available. We need to look for recyclers which can recycle whole asphalt at the jobsite or in the stockyard, cleanly and  efficiently while meeting these criteria and a few others such as safety and integration into the clients methodology. Again, if we want to truly address this aspect  of environmental stewardship we need to look for  cost effective, clean, high performance recyclers . The good news is that these recyclers exist.

In the next episode we will look at the financial advantages of asphalt recycling.

Episode VII – Infrared heat

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Episode VII   Infrared Heat

If it weren’t for Infrared heat life would not be possible on earth, as a matter of fact the amount of infrared heat received by this corner of the universe makes this planet very special indeed.

Infrared light is a wavelength just outside the  human visible spectrum which produces heat. This heat is produced when molecules, excited by the infrared radiation start colliding with each other and create heat as a by product of this friction. These properties were first identified by Sir Wm. Herschel around the year 1800 and exactly how much heat was given off by a radiating body was first measured by Tyndall. Based on these measurements, it was concluded by Stefan in 1879 and derived thermodynamically by his student Boltzmann that the heat emitted was proportional to the difference of the fourth power of the absolute temperature of the emitter. This is now know as the Stefan-Boltzmann law; the constant is expressed mathematically by the formula:  E= 5.67 x 10-8  w/m2  x K4 .   The constant is written as ‘’σ’’.

In simpler terms for example, if we double the temperature of the emitter we won’t double the heat output but rather we will see a 2 X 2  X 2 X 2 = 16 fold increase in the heat emitted! Obviously every degree of additional temperature at the emitter results in a large increase in the  efficiency in heat transfer. The difference between a 1500°f emitter and a 1875°f emitter will provide approximately a 25% increase in heat. Infrared operating efficiency is simply higher than other heat sources. This is what makes infrared such a clean, safe and efficient source of heat, and it reduces oil dependency. This fits in very well with our good asphalt stewardship requirements for cost effectiveness, performance and minimal environmental impact.

Episode VI – Propane and Natural gas as fuel for recyclers

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Episode VI  Propane and Natural gas as fuel for recyclers

These fuels have two drawbacks:

1-     They are mostly a non-renewable resource.

2-     They have decreased energy content compared to liquid fuels so they require larger storage tanks.

In spite of this, they have very attractive benefits:

1-     They burn cleaner than kerosene or diesel.

2-     They are exceptionally safe due to their low flammability range, meaning the air/fuel ratio required for ignition is relatively narrow.

3-     They are readily available and easy to access.

4-     Their price per BTU is less than their traditional competitor kerosene.

A gallon of propane contains 91,600 BTUs and a gallon of kerosene contains 135,000 BTU. That makes sense because the gas is less dense than the liquid. The  scales begin to tip in favour of propane when you consider the price per BTU and the efficiency of infrared heat transfer. Infrared heaters are around 20%  more efficient than kerosene burners. Don’t be fooled by BTU/hr heat ratings on heaters. It is important to note that the BTU/hr rating of burners refers to their fuel consumption rate and not their heat output. Because the efficiency of infrared is so much greater, BTU’s/hr  alone become meaningless as a measure of heat transferred to the asphalt. The real measure of  an asphalt recycler’s fuel efficiency is its capacity to soften a given quantity of asphalt without altering or destroying the asphalt cement binding characteristics. Choosing a heat source based on BTU/hr output is like judging the performance of an automobile solely on the amount of gasoline it burns.

Propane gas is heavier than air and natural gas is lighter than air. This accounts for the different gas pressures required to move them. Propane burners generally operate in the 11’’ WC (Water Column) gas pressure range whereas natural gas burners operate closer to 5-6’’ WC.  Propane will accumulate at the bottom of a container whereas natural gas will not, which incidentally is one of the reasons natural gas is considered a safer cooking fuel aboard boats.

They do not generally compete with gasoline and diesel for crude oil which tends to stabilise supply and demand and by consequence stabilise the price. Propane and natural gas burn cleaner, are less expensive and safer to handle and store. This makes them the green fuel source of choice for clean asphalt recyclers.

Endless curiosity leads to amazing experience

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The focus of this series of opinions will be road recycling. I’m sure everyone understands the individual words road and recycling but the combination of the two can take us in a whole new direction at warp speed when we factor in good environmental stewardship. This new direction is a wide boulevard but I find the way crowded with misconceptions, out-dated ideas, self-serving claims and narrow minded objections. My  wish is to give the asphalt recycling discussion a place to ferment progress.

Originally, taverns were places where discussion was loud, well fuelled and opinionated so the term ‘’virtual tavern’’ has a attractive ring to it.  However, ‘’virtual beer’’ may be the most soul destroying term I’ve ever heard in my life so we will have to count on good ideas to fuel the discussion.

Blame it on genetics I guess, my great-grand-father Jos, that’s him in the center of the photo my late father and all my brothers are involved in machinery. Like I said:  genetics.  When I cut myself, I bleed hydraulic fluid.  I have spent 10X more hours in the field than behind a desk. I’ve been branded a ‘’green collar worker’’ which I consider to be an honour. I’ve been fortunate enough to work closely with such technologies as laser tunnel guidance systems, pavement planers and of course asphalt recycling. I invented the modern asphalt cold-joint heating process and was granted a U.S. patent for my efforts.  Some of my work  was chronicled in Nick Fonda’s collection of short stories ‘’Roads to Richmond’’ (available from all reputable publishing sources, of course). I’ve accumulated a lot of observations about what works in the real world in equipment design in general and asphalt recyclers in particular during my life and career and will discuss some of them in detail during the following episodes.

More specifically we will examine how  asphalt recycling directly impacts both our pocket book and our environment. I consider existing roads as asphalt banks. We have been making deposits to these accounts for decades. The heavy financial and environmental costs of this asphalt has already been paid, and the material is already in our yards. Recycling whole asphalt chunks to produce a high quality material is the most economical way of supplying hot asphalt for road repairs. It is like finding free asphalt.

 

My passion for machinery is expressed in a more tangible form through the equipment I custom design and build for my clients and through sharing input wherever or whenever the subject is discussed. In this series I’ll endeavour to share my opinion on ‘’what I know, what I don’t know and what I suspect’’ as Colin Chapman once said. I hope my opinions will be interesting and bring some clarity to just exactly how, in a practical sense we can manage our environmental stewardship of asphalt.  Most of all I would like to stimulate the discussion, because there is a lot at stake. We are past the point of  denying elephants in the room and if one’s  opinion is to offer any value one must provide clear concise input based on critical thinking. Please share your opinions with us via email, Ben Franklin would be proud of all of us.

Episode V – The heat cycle of bin type recyclers

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Bin recyclers use the cleanest technology available to recycle just the proper amount required for the day.

In spite of being the cleanest, most efficient and economical method of recycling asphalt, bin recyclers are often self-servingly accused of being ‘’slow’’ or having low production rates. Duh! The bin output is tailored to the job requirements, they don’t heat more asphalt than needed. . That’s the whole point of environmental stewardship!

Just because someone heats asphalt does not make their process clean or environmentally friendly.Some people still don’t get it and perhaps they never will. Success will hinge on our ability to  stay focused and manage these details while not loosing sight of the ultimate goal.

Bin recycling has proven to be the cleanest most efficient method of recycling excavated asphalt. It is, by nature, a static process where the amount of asphalt recycled is tailored to the next day’s patching schedule. They are built in different configurations and capacities but they all use the same heaters and automated operating controls  and are loaded once per shift. The top ten reasons, (and by these do not mean to diminish the importance of a dozen others) why a static process is used, are:

1-     It produces little or no smoke or noise during the process.

2-     It maximises the recycling process by recycling 100% of the asphalt.

3-     It does not burn the asphalt cement.

4-    No additives are required to replace burnt asphalt cement

5-     It delivers the proper quality and quantity of patching material to the job.

6-     It requires the least amount of manpower.

7-     It requires the least amount of auxiliary equipment for re-handling.

8-     It creates the least amount of disturbance to traffic.

9-     It requires the least amount of maintenance.

10-  It has the longest life cycle and is 99.9% recyclable itself.

11- It is less expensive to purchase.

 

OK, so that was eleven. But really, there is no Santa Claus; proper environmental stewardship also means applying critical thinking to what we see or what we are told. There are still manufacturers who insist on force heating the asphalt to soften it more quickly. This  produces toxic smoke from the burnt asphalt cement which must then be replaced by oil based additives. The end product is poor quality patches that don’t last. They may call it recycling, but I just call it absurd.

Episode IV – Why recycle?

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We will concern ourselves here with recycling asphalt to repair damaged roads, we will cover other forms of recycling in a later episode.

One of the by-products of using asphalt to build roads and parking is leftover asphalt. Lots and lots of leftover asphalt. As we said in episode one, each one of the components is getting more expensive to produce new. The amount of green house gasses released in order to produce new graded stone and sand, to drill, pump, refine and haul oil to produce asphalt cement is astronomical when compared to the energy required to recycle existing asphalt.

Every repair jobsite produces leftover material either in the form of excavated chunks or leftover virgin hot-mix. This material can and should be re-used for repairs and the most efficient and clean way of recycling any product is to use it whole at the jobsite. The less we manipulate the material the cleaner and less expensive the recycling process will be. These leftovers can be in the form of excavated chunks, cold-planed chips, asphalt curbing, ‘’cold-patch’’ asphalt or leftover virgin hot-mix. Each one of these materials has its advantages and disadvantages but the bottom line is that they can all be recycled cleanly and quickly at the jobsite.

Recycling asphalt for repairs can be as easy as loading an asphalt bin once per shift, turning on the automated controls and walking away. The automated controls will provide the proper amount of heat to gently soften the asphalt without altering its binding characteristics. When we recycle our asphalt, there is no need for our trucks to wait (and wait) in line at the asphalt plant every morning while the rest of the crew stands idle or performs make work tasks. The free asphalt is already on the jobsite and the whole crew is ready to go.

So now that we have free hot asphalt and a full crew ready for work, we can use heated mobile recyclers to transport the asphalt directly to the repair site. This will insure that we avoid material waste due to cooling. We can recycle whole asphalt on the job or in the yard at any time of the year, in any location. That is how I see long-term environmental stewardship with regards to road maintenance.

Join me in episode V where I ‘ll talk about specific types of recyclers.

Episode I – What is asphalt?

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Here is my 5-minute primer on asphalt composition, on sale today for only 2 minutes.

Asphalt or bituminous concrete is a mixture of stones, sand, a few trace elements and a black oil based tar called appropriately enough Asphalt Cement or AC.  The stones give it strength, the sand fills in the voids between the stones and the asphalt cement binds it all together. The stone and sand is heated in a large rotating drum and then the AC is added and the materials are all mixed together and dumped in a truck for delivery to the jobsite. At the jobsite it must be laid and compacted before it cools. The mat must be laid down hot within a certain temperature range. Asphalt which has lost its heat can no longer be worked and must be discarded.

Asphalt is everywhere; it is so common as to be invisible. And for the most part it needs constant maintenance and this maintenance usually requires the same expensive process we described earlier and the old material must still be disposed of. Every one of these raw materials is becoming scarcer and more expensive every day. The cost of extraction and transportation of the raw materials and their subsequent transformation place an incredible strain on our budgets and our environment.

Remember walking on pavement barefoot in the summer? Man, now that was hot!  The radiant heat of the sun could almost melt the road. Exactly how much heat is radiated can be measured and we will get to  Stefan, Boltzmann and co. in a later episode. How about if we built a machine that could soften the asphalt in much the same way the sun does? If we apply the right technology we can concentrate enough heat on the asphalt to soften the asphalt cement without burning it. This would allow us to either rework old asphalt or allow us to reheat leftover virgin hot mix. But, introduce too much heat and the result will be blue smoke composed mostly of V.O.C.s because the a.c. coating on the stone and sand will have been burnt. Too little heat and we won’t get enough heat penetration into the road surface to allow full depth repairs.

Episode II – The downside of asphalt

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It could be severe weather conditions, heavy traffic loads, poor construction or lighter usage design criteria but I have seen asphalt fail all around the world.

From Chile  to China and Russia, all over the U.S. and Canada including the arctic, asphalt fails for the same reasons. Even though every locale swears that their asphalt is completely different. If there were such a thing as asphalt DNA (humm, perhaps there is…), we could prove that to be wrong; it’s the myth of fingerprints as Paul Simon would say.

Does this mean we should avoid using it? Not in the foreseeable future, we have millions of tons already installed and paid for, the heavy financial and environmental cost of which has already been paid. We have an impressive infrastructure dedicated to the asphalt industry and it is the livelihood of hundreds of thousands of people worldwide. Good people built the web of arteries connecting this planet one mile at a time.

Everyone hates potholes, well there maybe a few politicians and news reporters who can’t get enough of them, but they are generally hated because the damage they do to our cars and trucks.  I’m not necessarily talking about the ‘’big one’’ that will try to swallow your average Toyota or Honda whole, bending rims and steering rods, blowing tires and under body shields to pieces. The cumulative effect of smaller ones will be just as destructive. Potholes are just one of many asphalt failures which are all related and have the same root: cracks. We will examine this root in detail in episode III.

One of the main attractions of asphalt versus concrete remains the cost of purchase and asphalt is easier to repair or patch. It also has a lower life expectancy than concrete as a road way. Approximately 85% of our existing roads and parking areas are covered in asphalt. Concrete is generally used on major highways and in and around large cities, everywhere else asphalt is the material of choice. But there is a shining bright side because asphalt is an ideal material to recycle. If done properly it is incredibly cost effective and environmentally friendly. But nothing is ever as simple or as obvious as we imagine. The trick is to identify the characteristics of what constitutes a clean, effective asphalt recycler.

Episode IX – Financial advantages

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What are the Financial advantages of recycling? How about free asphalt mix for starters!

I consider existing roads as asphalt banks. We have been making deposits to these accounts for 100 years. The heavy financial and environmental cost of this asphalt has already been paid, and the material is already in our yards. Recycling whole asphalt chunks to produce a high quality material is the cleanest, most economical way of supplying hot asphalt for road repairs.

Automated controls will take over operation of the recycling process once the unit is loaded, avoiding labour inconsistencies. The availability of hot asphalt where and when we need it will relieve manpower and equipment scheduling conflicts. When we recycle our asphalt, there is no need for our trucks to wait (and wait) in line at the asphalt plant every morning while the rest of the crew stands idle or performs make work tasks. The free asphalt is already on the jobsite and the whole crew is ready to go.

So now that we have free hot asphalt and a full crew ready for work, we can use heated mobile recyclers to transport the asphalt directly to the repair site. This will insure that we maximise the use of our asphalt and avoid material waste due to cooling.

Remember that we can just as easily soften virgin asphalt as excavated asphalt. By breaking the bond between when asphalt is produced and where and when it is laid down, the cost of repairs is greatly reduced and we maximise our investment in raw materials and reduce oil dependency. Remote location, time of year, plant availability, haul truck availability, skilled labour availability are no longer impediments to accessing hot asphalt

Episode III – Alligatoring for non-swamp people

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Alligatoring is just one type of pavement failure characterized by its namesake. It generally signals that  the pavement has reached the end of its original lifespan. Here’s the bad news: Most pavement problems and failures are exacerbated by foundation failures and not the pavement itself.  Here is the worse news: We will never have enough money in our budgets to tear up the asphalt and fix all the foundations when all we wanted in the first place was a smooth road surface. But, there is good news: Every bit of that broken pavement can be recycled directly in place or off site and re-used in its entirety

Potholes may be the poster boy for pavement failures but they are really just a phase of asphalt deterioration. Let’s look at a single crack, the mother of all other failures. What a single crack will do is allow water to reach the foundation and start working its magic. For those of you saying that it doesn’t rain in your part of the country, don’t feel left out, the unrelenting sun will pose its own set of problems.

Much like the shore of a lake, once the foundation starts to wash away the loss of support for the surface asphalt mat accelerates the deterioration. On roads much of the damage is caused by the fact that vehicle tires compress the water into the cracks and it scours the foundation much like sticking the nozzle of a water hose into the foundation. In northern climes, the freezing and thawing cycle will also put pressure on the already strained foundation. While the erosion process happens over a matter of weeks or months, once started, it will spread the crack by washing away more and more underlying support. This can be recognized by the creation of a series of progressively larger semi circle cracks extending outward from the original crack until finally a fully formed pothole emerges. Now things can really start to unravel.

The longer we wait before we start treatment the worse the problem will become. Timely interventions will add years to pavement life. Crack sealing is often used as first line of defence but its application methodology must be strictly enforced if it is to be effective. Any method, which aims to repair asphalt, must address the initial crack formation at the source. For this we will need heat.