 |
|
|
| Resperion's
documents are available as PDF files.
If you don't have the reader installed
on your system,you can download
it free here. |
|
|
|
|
|
History
How long has this product
been in existence?
Chemcrete was invented in 1977, and was immediately
put into testing in several countries. Chemcrete was
patented in the United States, as well as over 30
other countries. Large scale testing in Europe began
in 1979 by a number of national road research authorities.
Lab and field tests were carried out in the UK by
Tarmac Roadstone Limited. The Danish Road Directorate
carried out tests, followed by the Autostrade in Italy.
The first 2 years were spent in conducting extensive
lab testing and evaluation followed by another two
years of road surface trials. The outcome of these
rigorous tests and trials produced commendable results
and led to governmental approvals and acceptance of
the Chemcrete technology in the UK, Italy and Denmark,
in which over 200 Chemcrete implementations were carried
out.
Is this product same
as Chemcrete?
IntegraBase is the successor product to Chemcrete
and is basically the same. Resperion has made some
minor modifications to the formulation to improve
certain performance metrics such as blending optimization
and cure time reductions. The name of the company
was changed to Resperion when the Company was acquired
by its new management.
We have heard that
there were cases of Chemcrete not working?
When Chemcrete was first introduced to the market
in the 1970’s, it was originally used in both
wearing courses and in base/binder courses. In some
of the wearing course implementations, there were
cases where cracking took place. It was soon discovered
that since the Chemcrete reaction was dependent on
Oxygen, the wearcourse was continuing to react as
it was exposed to oxygen. Since the wearcourse was
less than 4 Inches (which is now the minimum thickness
of a basecourse for IntegraBase,) it became too strong
and cracked. As soon as this was discovered, Chemcrete
was never used in another wear course. To date, there
has never been a problem with an IntegraBase or Chemcrete
modified base/binder course.
Where has Chemcrete/IntegraBase
been used around the world?
This technology has been used in over 100 projects
in countries all over the world. Here are just some
of the countries that have used Chemcrete/IntegraBase:
1. North America
- Kansas, Luisiana, Colorado, California, Texas, Iowa
2. Europe
- Denmark, Germany, Italy, Turkey, UK, Poland, Russia
3. Asia Pacific
- Indonesia, Thailand, Philippines, Malaysia, China
4. Middle East/Africa
- Saudi Arabia, Afghanistan
5. South America
- Argentina, Mexico
back to top
Testing
Are there any tricks
to preparing a good modified mix sample, or steps
that are imperative to obtaining a good reaction –
mixing, curing, etc.?
The modifier should be put into the kettle first,
and then the bitumen should be added and then blended.
This can cut down on blending time. The most important
single step is mixing – “if they don’t
meet, they don’t mate.” Since we are a
catalyst, it is imperative that out product be well
dispersed throughout the bitumen. It is also important
that the temperatures and time limits in the testing
instructions are met, to ensure the proper catalytic
reaction.
Are there any tests
that IntegraBase shouldn’t be subjected to?
Accelerated aging tests are not recommended by Resperion
because our catalytic reaction is dependent on temperature
and oxygen exposure. Any overexposure to high temps
and oxygen will continue to drive the reaction of
IntegraBase and will have negative results. IntegraBase
would never be subject to conditions as those presented
in the test, so the test isn’t a realistic determination
of aging for our product. We also usually suggest
to stick with Forced ductility tests, as force is
included and it is a more realistic test for a product
that increases modulus as we do.
Are there any “controls”
that we should not test with such as bitumens, temperatures,
aggregates, additives, etc.?
No
What are some Specific
IntegraBase tests and their expectations?
Resilient Modulus
- Expect a doubling at 40 deg. C at a lower rate of
loading – tripling is not out of the question.
Marshall Stability
- Typically a 25-30% increase
Indirect tensile Strength
- Tensile strength at higher temps usually doubles
Wheel Tracking
- 40 Deg C, half of the depth of the track of the
control
Stripping
- We are always better with wet strength. IntegraBase
tends to lose a higher percentage after soaking (retained
strength ratio), but looking at it relatively, IntegraBase
still has a higher wet strength both before and after
soaking when compared with an unmodified sample.
Are there certain aggregates
or bitumens to be cautious about?
Hydrophillic aggregates should be looked at carefully,
as they would be with any unmodified mix. Paraffinic
asphalts can be very difficult to work with. These
types of asphalts will crystallize at low temperatures
– this can be worse than cracking. Again, the
same can be said for unmodified mixes.
How much product is
required for a full battery of tests?
16oz
What if I don’t
have a high shear blender to mix the bitumen and IntegraBase?
That is ok, it is just important that the IntegraBase
is thoroughly mixed with the bitumen. We have had
labs use something as simple as a household blender
to mix the liquids together.
Are there any parameters
that must be met for a successful road test –
i.e. length, width, depth, etc.?
At least one kilometer in length. Stop/start testing
can be very difficult to achieve good results for
modified asphalts - continuous production is better.
Thickness minimum of 10cm. Width doesn’t matter.
back to top
Mix Design
Can IntegraBase be
used with any bitumen?
Yes. The amount of IntegraBase reaction is dependent
on the orgin of the bitumen. The reaction of IntegraBase
with different bitumens is fairly constant –
the main difference being the quantity of catalyst
required to drive the reaction. The apparent difference
is the quantity of catalyst lost in other secondary
reactions; this is the sole reason that it is recommended
that at least 2% modifer by weight of bitumen be used.
The variable which determines how reactive IntegraBase
is with the asphalt is the percentage of tetralin
structures contained in the asphalt. All asphalts
have tetralin structures, but to varying quantities.
The more tetralin in the asphalt, the better the reaction.
Napthenic and aromatic asphalts tend to have the highest
quantities of tetralin structures – these asphalts
are commonly found in the middle east and Venezuela
regions. China and Russia tend to have asphalts with
the lowest percentage of tetralin structures.
Are there any types
of bitumen to avoid?
Parrafinic asphalts can be difficult to work with,
regardless of if they are being modified or not. These
asphalts can crystallize at cold temperatures causing
premature cracking. These types of asphalts are typically
found in China, Indonesia and Russia.
Does the 2% of IntegraBase
replace 2% of the bitumen, or can it be added on top
of the original mix design?
IntegraBase can be added on top, but it doesn’t
have to be. Since IntegraBase is an oil based product,
it can replace 2% of the bitumen without sacrificing
any integrity of the bitumen.
What is the optimal
void content for an IntegraBase mix – and what
are the minimum and maximum percentages?
IntegraBase the same problems that normal mixtures
have – below 3% you no have a mastic mixture,
as it will consolidate under traffic. Approx 3-7%
is ideal.
What is the optimal
binder content, and what are the minimum and maximum
percentages for an IntegraBase mix?
Same as an untreated mix.
What are the tolerable
percentages of IntegraBase, and what can happen on
the low and high end?
The majority of the IntegraBase reaction will be achieved
from 2%. Lower percentages will work better with some
bituments, but on average, 2% is most suitable for
all. There are no problems with using more than 2%,
however there will be no benefits, and would just
result in a waste of product.
What are the most optimal
aggregates to use?
Granite is preferable. Acidic and hydrophilic are
the most concerning, as with any mix design. IntegraBase
doesn’t make any aggregates less suitable. Gradation
isn’t as important when IntegraBase is being
used. Uncrushed, single sized materials are usable
with IntegraBase.
Are there any aggregates
that IntegraBase doesn’t work with?
None other than ones that wouldn’t be suitable
for untreated asphalt
Are there any special
requirements for the use of certain aggregates with
IntegraBase – i.e. washing, treating, etc.?
None other than normal practice. Dusting is always
important.
Has IntegraBase ever
been used with any other additives?
IntegraBase has been used with an SBS in Europe –
IntegraBase doesn’t affect polymers. PDM from
BP has also been used before. Lime has been used for
anti-stripping purposes.
Can IntegraBase improve
recycled mix (RAP) added to the mix?
It must be a very small percentage of RAP (less than
50%), otherwise you lose the necessary chemistry.
We will be ineffective commensurate with the percentage
of RAP (i.e. we will be probably be about 15% less
than our optimum effect with 15% RAP.)
back to top
Pavement Design
Can IntegraBase be
used in the wear course?
IntegraBase is only suitable for use in sublayers
of pavement structures – base courses and binder
courses, and should NEVER be used in wearing courses.
Since oxygen is a catalyst in the IntegraBase modification
reaction, the use in the wearing course can cause
the reaction progress over time, which can lead to
premature strengthening of the mix. When IntegraBase
is sealed in a sublayer, the reaction will subside
with maximum performance improvements in place.
What characteristics
of a wear course are important when using an IntegraBase
sub layer?
Flexibility. We typically advise using a thin wear
course, as we don’t want it to be a load carrying
member; friction and drainage are the most important
thing, to basically serve as a good cover.
Are there any wear
courses that should be avoided when using IntegraBase?
No
What kind of sealant
or overlay will guarantee sealing off IntegraBase
from its catalytic reaction?
All overlays should provide significant protection
from oxidation. 19mm of thin film overlay, and any
type thickness of thick film should be sufficient.
What instances would
it make sense to use an IntegraBase treated binder
course?
The new soft base road, with a strong intermediate
layer. Carl Monismith in California has been working
with this design for a while. This can eliminate reflective
cracking, and won’t allow cracking to propagate
up.
Are there any binder
designs that wouldn’t lend themselves to using
IntegraBase?
No, Monismith’s design is the only one currently
in use.
Are there any specific
requirements of the layers above or below the binder
course?
No, it is a function of the base vs. the binder.
What is the minimum
reduced thickness of an IntegraBase base course?
4 inches or 10cm
Are there situations
where the use of IntegraBase in the base course isn’t
a good idea?
No, as long as you have 10cm there is no reason it
couldn’t be used.
What are the requirements
for a sub base?
You want good wet strength, and to stay away from
plastic soils. The higher the CBR the better off you
are. Soil replacement isn’t usually too expensive.
Are there any types
of sub-bases that should be avoided, i.e. Rubblized
PCC, etc.?
None other than plastic soils. Good rubblizing is
important, as you don’t want large pieces of
concrete moving around under your asphalt.
How much moisture is
tolerable in the sub base?
Over 7-7.5% water can be a problem. Even for non-plastic
soils.
back to top
Implementation
Does the plant type matter –
Batch vs. Drum?
No, as long as all directions are followed, the plant
type bears no difference.
Are there any special
requirements for the plant – computerized equipment,
space, etc.?
Static mixers are quite helpful and inexpensive ($1k).
This doesn’t affect their operation when IntegraBase
isn’t being used. Other than that, IntegraBase
can be used at any plant, regardless of equipment
or technology available.
What equipment is required
to use IntegraBase at the plant?
A simple pump and meter system is required to dose
and deliver the IntegraBase into the bitumen feed
line. If temperatures are cold (typically 40 deg.
F or less,) heating blankets are suggested to keep
IntegraBase at an optimal viscosity for pumping. Resperion
will typically provide all of this equipment, along
with an engineer to set everything up.
What is the ideal temperature
for IntegraBase to be pumped at?
100 deg. F – doesn’t take a lot of effort
to get it to 90-100. Acceptable range can be above
75 degrees. Anything lower will lead to burned out
pumps, etc.
Is it necessary to have a back up pump or
meter on hand, or any other equipment?
This is a must, because once a pump or meter is down,
you will be unable to dose the product. Pumps are
the most important as meters rarely fail. The pump
and meter systems that Resperion provides always has
a secondary pump in case the first one fails or burns
out.
What is the ideal medium to pump IntegraBase
from – tote, drum, custom container, etc.?
Drums can be difficult to handle, as they only hold
55galons. However, all work fine for pumping.
Can IntegraBase cause any problems to any
of the equipment at the plant?
IntegraBase contains no fines to disrupt the valves
or gauges at the plant, such as other modifiers. Our
chemicals are very pure (HP- high purity), which don’t
create buildup on valves, etc.
What is the ideal temperature to mix at,
and what are the issues with temps being too high
or low?
1350-1450C. If IntegraBase is blended too hot, there
could be some odor and light smoke from the light
ends burning off. There are no deleterious side effects
from the high temperatures though. The only issue
with the low temperatures could be the mix losing
too much temperature before compaction. IntegraBase
improves the compactability of the mix, so the lower
temperatures are not as important as they are with
unmodified mix.
How long should IntegraBase treated asphalt
be mixed for – are there issues with mixing
too long or short?
Time is the same as normal mixing.
Is there an odor associated with the mixing
of IntegraBase – if so, is there any way to
circumvent it?
Above 1500C there can be an odor from some of the
ingredients in the product burning off.
Once the IntegraBase mix has been manufactured,
are there any options for storage? If so, what are
the timelines?
Initially the penetration increases during mixing
(asphalt is softer), but with time the asphalt will
harden. You don’t want to store the manufactured
asphalt – it should be laid down the same day
it is produced. Trucks can be tarped, float CO2 between
the asphalt and tarp to cut oxygen. Typically 30-40
minutes between mixing and laydown is the optimal
cure time.
Are there any special techniques that need
to be used during the compaction process?
No – everything is rolled and compacted as normal.
Densities are easier to achieve with the IntegraBase
modified asphalt as it acts as a lubricant to the
mix.
Is there any machinery or tools that should
be avoided when working with IntegraBase modified
asphalt?
No, although it is important that pavers are used
and all traditional methods are followed. Narrow placement
areas can be difficult when HMA is placed by hand.
Are there any special requirements for the
trucks that transport IntegraBase modified asphalt?
No, no release agents needed. Tarps can be recommended
due to the cooler temp of the asphalt.
How long can IntegraBase modified asphalt
be exposed to traffic before being surfaced?
It can be left unsealed 30-60 days without a cover,
sometimes longer depending on the temperatures. The
hotter the temps, the quicker you will want to place
a wearing course. It is imperative that it is covered
though, as sometimes seals or wearing course are not
placed due to budgetary cuts or simply forgetting
to do so.
back to top
Performance
Please explain in engineering
terms how IntegraBase improves the road structure
– stress, strain, etc. Please note if there
are different explanations for use in binder or base
course applications?
The two main reasons: changing the molecular weight
of the asphalt, giving it the strength that it has.
The aromatic platelets get crosslinked, linking the
platelets vertically as well as the traditional horizontal
link. This crosslinking eliminates the typical flow
of asphalt. Base/binder course doesn’t make
a difference. When a load is put on a beam (the beam
flexes), the top molecules push together, and the
bottom molecules pull apart. This puts the top in
compression and the bottom is in tension. This is
the difference between cracking. If the binder is
in compression, it can’t crack. IntegraBase
keeps the base/binder course in constant compression
(or constant stress). It is important to try to put
the tension deeper into the road into the basecourse,
or better yet, into the subbase, then you can eliminate
cracking.
How does IntegraBase
modified asphalt hold up to extreme temperatures –
both hot and cold?
Temperature swings in the basecourse are quite flat.
IntegraBase flattens out the temperature susceptibility
curve of asphalt, improving performance on both the
high and low end. Freeze/thaw can be troublesome due
to the water in the basecourse. The water expands
at different temps to break up the asphalt (this is
common with all asphalts, and IntegraBase modified
asphalt would be better than untreated asphalt.)
Can humidity or dry
air affect IntegraBase modified asphalt?
If sealed, the type of air is unaffected
How does IntegraBase
modified asphalt perform in these different situations?
a. Constant heavy loads (truck routes)
- Rutting is a huge problem here, our modulus and
higher viscosities provide the strength to overcome
problems. Since it is shear susceptible, the slower
the rate of loading, the higher the apparent viscosity,
the less the asphalt will flow in the mix.
b. Repetitive wheel paths (bus lanes, ports)
- Same as above
c. Normal traffic (passenger cars, etc.)
- Light, fast traffic really causes no problems for
asphalt. IntegraBase does help with fatigue, increasing
the number of ESAL’s a pavement can typically
handle.
d. Stop and Go traffic (intersections)
- Pushing and shoving are a big problem here, the
slow rate of loading is beneficial for our strength.
Sliding plate viscometer test can measure shoving.
Increased viscosities exponentially improve asphalt’s
shoving principles.
back to top
|
