Note: Descriptions are shown in the official language in which they were submitted.
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ASPHALT MIXTURE, PROCESS FOR PRODUCTION OF SAME, AND PAVING
METHOD USING SAME
TECHNICAL FIELD
[0001]
The present invention relates to an asphalt mixture to
be used for road pavement and a process for production of
the same, and also relates to a paving method using the
same.
BACKGROUD ARM
[0002]
A hot asphalt mixture is usually used under an initial
compacting temperature within a range of 110-140 C, such as
provided by Pavement Construction Handbook ("Hosou Sekou
Binran" in Japanese). However, even though the hot asphalt
mixture can have a large strength immediately after being
paved, the available period of time is until the temperature
of the mixture decreases. Therefore, the application of the
hot asphalt mixture may be difficult under various
conditions, such as when a small amount of the mixture is
divided to be used several times, when the mixture is
transported for a long period of time, and when the
constructed thickness is thin, such as in a thin layer
overlay method, and the temperature significantly decreases
immediately after the mixture is spread.
[0003]
Accordingly, a hot asphalt mixture that uses a warm-
mix technique and an ordinary temperature construction-type
asphalt mixture are focused. The hot asphalt mixture that
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4
uses a warm-mix technique, i.e. a warm-mix asphalt mixture,
is generally said to be able to extend the available
temperature range of the hot asphalt mixture toward the
lower limit side by about 30 C. The ordinary temperature
construction-type asphalt mixture is an asphalt mixture that
is said to allow the pavement construction under ordinary
temperatures (100 C or lower).
[0004]
As an asphalt mixture that can be constructed under
ordinary temperatures or under temperatures within a warm
temperature region, for example, a so-called cutback asphalt
mixture is proposed in which the viscosity of the asphalt
mixture is forcibly reduced using a mineral oil or the like.
In the cutback asphalt mixture, as disclosed in JP11-12475A,
the asphalt is softened using a cutback material such as a
mineral oil, and the strength of the asphalt mixture is
developed as the cutback material is volatilized. However,
according to the method in which, as described above, the
asphalt is "cut back" using a mineral oil or the like
thereby to forcibly reduce the viscosity at the time of
pavement construction, there are drawbacks in that the
mixture strength when the traffic of a road is opened, for
example, may considerably deteriorate and the curing may
require a long time.
[0005]
An ordinary temperature construction-type asphalt
mixture using an asphalt emulsion is also proposed, but the
mixture has a relatively low strength even though the
aggregate is not required to be heated and dried, and the
applicable field may be limited because the decomposition
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rate of the asphalt emulsion may have to be taken into
consideration. In addition, in the ordinary temperature
asphalt mixture using an asphalt emulsion, the asphalt
emulsion may possibly flow out if it rains before the
emulsion is decomposed after the pavement construction.
[0006]
In such a situation, JP Patent No. 5583978 discloses
an ordinary temperature construction-type asphalt mixture
that can be constructed under ordinary temperatures. This
asphalt mixture uses a tall oil fatty acid as the cutback
material (see, for example, "Naval Stores -Production- -
Chemistry- -Utilization-" (published by Harima Chemicals
Group, Inc., June 1993), line 10 of page 474 to line 9 of
page 475). The tall oil fatty acid acts to reduce the
viscosity of the asphalt mixture thereby to allow the
pavement construction under ordinary temperatures. According
to this technique of JP Patent No. 5583978, the tall oil
fatty acid as the cutback material reacts with the cement
after the pavement construction so as to act as a curing
agent, which can thereby develop a sufficient strength.
[0007]
On the other hand, also in an asphalt mixture that can
be constructed under ordinary temperatures or under
temperatures within a warm temperature region, the pavement
body after the construction is required to have improved
characteristics, such as further enhanced strength,
durability, and flexibility. Therefore, an asphalt mixture
is desired which can improve these characteristics and which
can be constructed under ordinary temperatures or under
temperatures within a warm temperature region.
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=
SUMMARY OF THE INVENTION
PROBLEM TO BE SOLVED BY THE INVENTION
[0008]
The present invention has been proposed in view of the
above, and an object of the present invention is to provide
an asphalt mixture that can develop the strength within a
relatively short time after the pavement construction and
can give a pavement body having enhanced strength and
durability and excellent in the flexibility.
MEANS FOR SOLVING THE PROBLEMS
[0009]
As a result of intensive studies to solve the above
problems, the present inventors have found that, when
producing an asphalt mixture, a lubricative solidification
material that contains an oleic acid at a ratio of 60 to 85
wt% and an alkaline additive material are added to and mixed
with an aggregate and an asphalt to decrease the viscosity
of the asphalt thereby to allow the pavement construction
under temperatures within a low temperature region to
ordinary temperatures and further to temperatures within a
warm temperature region (e.g. -20 C to 120 C, preferably
-10 C to 100 C), while a hardening accelerator is fed to the
mixture at the time of pavement construction so that the
added lubricative solidification material and alkaline
component undergo a saponification reaction or a
neutralization reaction to increase the viscosity, and the
asphalt mixture can thereby be provided which can develop a
certain strength within a relatively short time. The present
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84006719
invention has thus been accomplished.
In particular, the present inventors have found that, by
using a lubricative solidification material that contains an
oleic acid at a ratio of 60 to 85 wt%, the obtained pavement
body can have enhanced strength and durability and can be
excellent in the flexibility while allowing the pavement
construction under ordinary temperatures or under temperatures
within a warm temperature region. The present invention has thus
been accomplished.
[0010]
That is, according to an aspect of the present invention,
there is provided an asphalt mixture comprising an aggregate, an
asphalt, a lubricative solidification material and an alkaline
additive material that are mixed together, wherein the
lubricative solidification material contains an oleic acid at a
ratio of 60 to 85 wt%.
[0010a]
According to another aspect of the present invention,
there is provided an asphalt mixture comprising an aggregate, an
asphalt, a lubricative solidification material and an alkaline
additive material that are mixed together, wherein the
lubricative solidification material comprises an oleic acid in
an amount of 67 to 85 wt%, a content of the lubricative
solidification material in the asphalt mixture is 3 to 50 wt%,
and the ratio of the lubricative solidification material and the
alkaline additive material is from 100:10 to 100:300 as a weight
ratio of lubricative solidification material:alkaline additive
material.
[0011]
According to another aspect of the present invention,
there is provided a paving method comprising: adding a hardening
accelerator to the above asphalt mixture; and subjecting the
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84006719
lubricative solidification material and the alkaline additive
material to a saponification reaction or a neutralization
reaction thereby to enhance the strength.
[0011a]
According to another aspect of the present invention,
there is provided a paving method comprising: adding an alkaline
additive material and a hardening accelerator to the asphalt
mixture as described herein; and subjecting the lubricative
solidification material and the alkaline additive material to
saponification reaction or neutralization reaction thereby to
enhance the strength.
[0012]
According to a further aspect of the present invention,
there is provided a process for production of the above asphalt
mixture, the process comprising: a first step of mixing an
aggregate heated to 100-170 C and an asphalt heated to 130-170 C
using a mixing apparatus; a second step of adding and mixing the
lubricative solidification material to a mixture obtained in the
first step; and a third step of adding and mixing the alkaline
additive material to a mixture obtained in the second step.
[0012a]
According to another aspect of the present invention,
there is provided a process for production of the asphalt
mixture as described herein, the process comprising: mixing an
aggregate heated to 100-170 C and an asphalt heated to 130-170 C
using a mixing apparatus to obtain a first mixture; adding and
mixing the lubricative solidification material to the first
mixture, to obtain a second mixture; and adding and mixing the
alkaline additive material to the second mixture, to obtain a
third mixture.
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84006719
EFFECTS OF THE INVENTION
[0013]
According to the present invention, the lubricative
solidification material having a low viscosity is added thereby
to allow the pavement construction under temperatures within a
low temperature region to ordinary temperatures and further to
temperatures within a warm temperature region (e.g. -20 C to
120 C, preferably -10 C to 100 C), while the hardening
accelerator is fed at the time of pavement construction so that
the alkaline additive material in the mixture is ionically
decomposed thereby to undergo a saponification reaction or
neutralization reaction with the lubricative solidification
material, and a high strength can thus be developed at an early
stage.
Moreover, according to the present invention, a
lubricative solidification material that contains an oleic acid
at a ratio of 60 to 85 wt% is used, and therefore a pavement
body can be obtained which has enhanced strength and durability
and which is excellent in the flexibility while allowing the
pavement construction under ordinary temperatures or under
temperatures within a warm temperature region.
DESCRIPTION OF EMBODIMENTS
[0014]
FIG. 1 is an explanatory diagram illustrating the
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concept of pavement construction temperature range for each
of the asphalt mixture according to the present invention
and a conventional asphalt mixture.
[0015]
The asphalt mixture according to the present invention
comprises an aggregate, an asphalt, a lubricative
solidification material and an alkaline additive material
that are mixed together, and is characterized in that the
lubricative solidification material contains an oleic acid
at a ratio of 60 to 85 wt%. The asphalt mixture according to
the present invention is designed such that a hardening
accelerator is added to the mixture at the time of pavement
construction so that the lubricative solidification material
undergoes a saponification reaction or neutralization
reaction with an alkaline component that is originated from
the alkaline additive material, and the strength is thereby
enhanced. In the present invention, water or the like may be
used as the hardening accelerator.
[0016]
The saponification reaction or neutralization reaction
as used in the present invention may be a reaction to
generate a fatty acid alkaline salt. Examples of the method
for such a reaction include a saponification method in which
an alkaline water is added to a fatty acid ester to generate
a fatty acid alkaline salt (soap) and glycerin and a
neutralization method in which a higher fatty acid is
neutralized by an alkaline water.
In the saponification reaction, if the alkaline
additive material is added in a solid form without any
solvent such as water, the reaction does not start in
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general. On the other hand, the presence of a solvent such
as water causes a reaction (saponification reaction or
neutralization reaction) of "(fatty acid and resin acid in
the lubricative solidification material)+(alkaline additive
material)+(water)=(soap (solid))" to generate a soap thereby
developing the strength.
[0017]
The asphalt mixture according to the present invention
is configured to contain an asphalt, an aggregate, a
lubricative solidification material, and an alkaline
additive material. The microstructure of the asphalt mixture
is considered as follows. That is, a lubrication film
configured of the lubricative solidification material having
a low viscosity and the alkaline additive material appears
to be present among aggregates formed thereon with asphalt
coatings thereby to develop some lubrication effect. This
allows the pavement body before the saponification reaction
or neutralization reaction to remain in a low viscosity
state. In other words, in the present invention, the
lubricative solidification material acts, before the
pavement construction, as a cutback material that reduces
the viscosity of the asphalt mixture under temperatures
within a low temperature region to ordinary temperatures and
further to temperatures within a warm temperature region
(e.g. -20 C to 120 C, preferably -10 C to 100 C)
[0018]
After such an asphalt mixture according to the present
invention is used for pavement construction, the hardening
accelerator (e.g. water) is sprayed thereon and compaction
is performed using a roller. Otherwise, after compaction
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using a roller, the hardening accelerator (e.g. water) is
sprayed. This allows the lubricative solidification material
and alkaline additive material contained in the asphalt
mixture to undergo a saponification reaction or a
neutralization reaction which solidify the asphalt mixture
under the presence of the hardening accelerator (e.g.
water), and the strength can thus be enhanced. When
performing pavement using the asphalt mixture according to
the present invention, the method of compaction is not
limited to a method using roller compaction and may
appropriately be selected in accordance with the purpose of
pavement. A method by beating may also be employed, for
example, depending on the purpose of pavement.
[0019]
FIG. 1 is a conceptual diagram illustrating a
relationship between the available temperature range
(construction temperature range) and the binder viscosity
for each of the asphalt mixture according to the present
invention and a conventional hot asphalt mixture (a hot
asphalt mixture that does not contain a lubricative
solidification material and an alkaline additive material).
The asphalt mixture according to the present invention has a
wider available temperature range than that of the
conventional hot asphalt mixture, and can be used for
pavement construction even under temperatures within a range
of -20 C to 120 C. Moreover, when the hardening accelerator
(e.g. water) is added to the asphalt mixture, the binder
viscosity can be promptly enhanced to a certain degree
comparable with that of the conventional hot asphalt
mixture.
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[0020]
Each material that constitutes the asphalt mixture
according to the present invention will then be described.
The asphalt mixture according to the present invention is
configured to contain an aggregate, an asphalt, a
lubricative solidification material, and an alkaline
additive material.
[0021]
The aggregate is not particularly restricted. Examples
of the aggregate to be appropriately used include those,
such as crushed stone, sand and stone powder, which may be
used for a typical asphalt for pavement. An aggregate of any
granularity range, such as dense-grade and open-grade, may
be used without restriction. As one example, an aggregate
may be used of which the 2.36 mm sieve passing mass
percentage is 15-80%, which is a ratio of particles that
pass through a sieve mesh with an aperture of 2.36 mm.
[0022]
The asphalt is also not particularly restricted.
Examples of the asphalt include straight asphalt and
modified asphalt, which may be used without any restriction.
[0023]
The aggregate and asphalt to be used in the present
invention may contain a recycled aggregate as substitute for
a regular aggregate.
[0024]
The lubricative solidification material to be used in
the present invention contains an oleic acid at a ratio of
60 to 85 wt%. According to this feature of the present
invention that the lubricative solidification material to be
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used contains an oleic acid at a ratio of 60 to 85 wt%, the
lubricative solidification material can act, before the
pavement construction, as a cutback material that reduces
the viscosity of the asphalt mixture under ordinary
temperatures or under temperatures within a warm temperature
region. This allows the pavement construction under ordinary
temperatures or under temperatures within a warm temperature
region, while the pavement body obtained by solidifying the
asphalt mixture can have enhanced strength and durability
and can be excellent in the flexibility. If the content of
the oleic acid is unduly small, the effect of enhancing the
strength, durability and flexibility of the obtained
pavement body will not be obtained. If the content of the
oleic acid is unduly large, the pavement construction under
ordinary temperatures or under temperatures within a warm
temperature region will be difficult. The content of the
oleic acid may preferably be 63 to 82 wt%, more preferably
65 to 80 wt%, further preferably 67 to 78 wt .
[0025]
The lubricative solidification material to be used in
the present invention may be sufficient if it contains an
oleic acid at a ratio of 60 to 85 wt%. However, in order to
achieve a more significant effect of enhancing the strength,
durability and flexibility of the obtained pavement body,
the lubricative solidification material may contain a
saturated fatty acid and an unsaturated fatty acid
preferably at a ratio of 1:99 to 20:80, more preferably at a
ratio of 2:98 to 15:85, and further preferably at a ratio of
3:97 to 12:88, as a weight ratio of "saturated fatty
acid:unsaturated fatty acid."
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[0026]
In order to achieve a more significant effect of
enhancing the strength, durability and flexibility of the
obtained pavement body, the lubricative solidification
material to be used in the present invention may preferably
contain a palmitic acid, stearic acid, linoleic acid, and
linolenic acid in addition to the oleic acid. These
components may preferably be each contained at the content
ratio as follows:
palmitic acid: preferably 1 to 15 wt%, more preferably
2 to 10 wt%, further preferably 3 to 6 wt%, and furthermore
preferably 3.5 to 5.5 wt%;
stearic acid: preferably 0.1 to 5 wt%, more preferably
0.3 to 4 wt%, further preferably 0.5 to 3 wt%, and
furthermore preferably 0.7 to 2.5 wt%;
oleic acid: 60 to 85 wt%, preferably 63 to 82 wt%,
more preferably 67 to 78 wt%, and further preferably 67 to
72 wt%;
linoleic acid: preferably 5 to 30 wt%, more preferably
6 to 27 wt%, further preferably 7 to 25 wt%, and furthermore
preferably 20 to 25 wt%; and
linolenic acid: preferably 0.1 to 5 wt%, more
preferably 0.3 to 3.5 wt%, further preferably 0.5 to 2 wt%,
and furthermore preferably 0.7 to 1.5 wt%.
[0027]
The lubricative solidification material to be used in
the present invention may preferably contain one or more
compounds selected from a group consisting of a lauric acid,
myristic acid, myristoleic acid, and palmitoleic acid in
addition to the palmitic acid, stearic acid, oleic acid,
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linoleic acid, and linolenic acid. The content of total of
the lauric acid, myristic acid, myristoleic acid, and
palmitoleic acid may preferably be 0.5 to 20 wt%, and more
preferably 1 to 15 wt .
[0028]
In the present invention, the linoleic acid
encompasses a conjugated linoleic acid that is an isomer in
which double bonds are conjugated, and the linolenic acid
encompasses an a-linolenic acid and a y-linolenic acid.
[0029]
The lubricative solidification material to be used in
the present invention may contain other components in
addition to the saturated fatty acid and unsaturated fatty
acid. Examples of such other components include a resin
acid. The resin acid may be a polycyclic diterpene that has
a carboxyl group and of which the carbon number is 20.
Specific examples of the polycyclic diterpene to be
preferably used include a rosin that contains at least one
type of abietic acid, dehydroabietic acid, neoabietic acid,
pimaric acid, isopimaric acid, and palustric acid. The
content ratio of the resin acid in the lubricative
solidification material to be used in the present invention
may preferably be 20 wt% or less, more preferably 10 wt% or
less, and further preferably 5 wt% or less.
[0030]
The content of the lubricative solidification material
in the asphalt mixture of the present invention may
preferably be 1 to 60 wt% in an embodiment and preferably 3
to 50 wt% in another embodiment to the total amount of 100
wt% of the asphalt and the lubricative solidification
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material. In an embodiment, in view of the use for the
pavement construction under temperatures within a warm
temperature region (e.g. 40 C to 120 C), it is more
preferred that the content of the lubricative solidification
material is 15 to 30 wt% to the total amount of 200 wt% of
the asphalt and the lubricative solidification material. In
an alternative embodiment, in view of the use for the
pavement construction under temperatures within a low
temperature region to ordinary temperatures (e.g. -20 C to
40 C), it is also more preferred that the content of the
lubricative solidification material is 35 to 50 wt% to the
total amount of 100 wt% of the asphalt and the lubricative
solidification material. According to the feature that the
content of the lubricative solidification material is within
the above range, it is possible to appropriately enhance the
strength, durability and flexibility of the obtained
pavement body without deteriorating other characteristics.
The additive amount of the lubricative solidification
material can be determined to match the condition for
pavement construction because the available temperature
range is extended as the additive amount of the lubricative
solidification material is increased.
[0031]
The acid value of the lubricative solidification
material to be used in the present invention is not
particularly limited, but may preferably be 170 to 220
mgKOH/g, more preferably 180 to 215 mgKOH/g, and further
preferably 190 to 210 mgKOH/g.
[0032]
The iodine value of the lubricative solidification
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material to be used in the present invention may preferably
be 95 to 160, more preferably 100 to 150, and further
preferably 110 to 145.
[0033]
The alkaline additive material is not particularly
limited if it is a compound that becomes an alkaline
component due to the action of the hardening accelerator
(e.g. water). The alkaline additive material may preferably
exhibit a low hydrogen-ion concentration (i.e. high pH) due
to the action of the hardening accelerator in order to
neutralize the fatty acid which includes oleic acid. It is
also possible to use typical ones, such as sodium hydroxide
and potassium hydroxide, which may usually be used in
soapmaking. From the environmental view point, however, an
ordinary cement (ordinary Portland cement) may preferably be
used which exhibits a low hydrogen-ion concentration due to
the action of the hardening accelerator among cements that
are used as typical civil engineering materials. Examples of
the ordinary Portland cement to be used include those which
contain, as main components, tricalcium silicate (3CaO-Si02),
dicalcium silicate (2CaO.Si02), calcium aluminate
(3Ca0-A.1203), calcium aluminoferrite (4Ca0-
A1203.Fe203),
calcium sulfate (CaSO4.2H20), and the like. Other than the
above, an aqueous solution that contains metal ions such as
sodium ions (Na), potassium ions (K+), magnesium ions (Mg2 )
and calcium ions (Ca2+), or a powder that contains a metal
salt generating the above ions by adding water, or sodium
hydrogen carbonate (NaHCO3), potassium hydrogen carbonate
(KHCO3), or other appropriate substance, may be used as the
alkaline additive material. The
content ratio of the
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alkaline additive material in the asphalt mixture according
to the present invention may preferably be within a range of
100:10 to 100:300 and more preferably within a range of
100:15 to 100:40 as a weight ratio of "lubricative
solidification material:alkaline additive material."
[0034]
Provided that the action and advantageous effects of
the present invention are not impaired, other additives that
are usually used in the field of asphalt pavement may be
added to the asphalt mixture according to the present
invention in addition to the above. Examples of such
additives include, but are not particularly limited to,
filler, plant fiber, pigment, and antifreezing agent.
[0035]
qFirst Embodiment
The asphalt mixture according to the present invention
may be produced by the method as will be described below,
for example, and the obtained mixture may be enclosed in a
bag that comprises a moisture permeation preventing layer
and a thermal fusion bonding layer, and can thereby be
stored for a long time (e.g. 6 months).
A process for production of the asphalt mixture
according to the present embodiment will hereinafter be
described.
[0036]
First, an aggregate is put into a mixing apparatus,
and dry mixing for the aggregate is performed. The dry
mixing may be performed under a condition in which the
aggregate is heated to 100-170 C, preferably 100-140 C, and
more preferably 110-130 C. The temperature and the amount of
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time for the dry mixing are not particularly limited, but
the temperature for the dry mixing may ordinarily be 100-
140 C and preferably 110-130 C, while the amount of time for
the dry mixing may ordinarily be about 1 second to 1 minute.
In the present embodiment, the aggregate is used in the
state of being heated to the above temperature thereby to
allow the water amount contained in the aggregate to be
controlled, so that the preservation stability of the
obtained asphalt mixture can be improved.
[0037]
Asphalt is then added to the mixing apparatus to be
mixed with the aggregate. In the present embodiment, after
being heated to 130-170 C and preferably to 140-160 C, the
asphalt is added to the mixing apparatus, and the mixing of
the aggregate and asphalt is then conducted. The mixing
temperature and mixing time during this operation are not
particularly limited if a certain condition is obtained such
that the asphalt layer is uniformly formed on the aggregate
surface, but the mixing temperature may ordinarily be 100-
140 C and preferably 110-130 C, while the mixing time may
ordinarily be about 1 second to 5 minutes.
[0038]
Subsequently, a lubricative solidification material is
added to the mixing apparatus to be mixed with the mixture
obtained in the above manner. The lubricative solidification
material may be used at ordinary temperatures, but may
preferably be used after being heated to about 15-25 C, such
as during the cold months. The mixing temperature and the
mixing time during this operation are also not particularly
limited, but the mixing temperature may ordinarily be 100-
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140 C and preferably 110-130 C, while the mixing time may
ordinarily be about 1 second to 5 minutes.
[0039]
Thereafter, an alkaline additive material is added to
the mixing apparatus to be mixed with the mixture obtained
in the above manner. The mixing temperature and the mixing
time during this operation are not particularly limited, but
the mixing temperature may ordinarily be 100-140 C and
preferably 110-130 C, while the mixing time may ordinarily
be about 1 second to 5 minutes.
[0040]
In the present embodiment, the aggregate and the
asphalt are mixed first, and the lubricative solidification
material and the alkaline additive material are then added
and mixed in this order thereby to allow the obtained
asphalt mixture to have a configuration in which: some
asphalt coating is formed on the surface of the aggregate; a
layer comprising the lubricative solidification material is
formed on the surface of the asphalt coating; and the
alkaline additive material in a solid form covers the
surface of the layer comprising the lubricative
solidification material. This can enhance the reaction
efficiency between the alkaline additive material and the
hardening accelerator, and even if a relatively small amount
of the alkaline additive material is added, the strength
improvement effect can sufficiently be developed when the
hardening accelerator is added. In addition, the alkaline
additive material may be added with a relatively small
amount thereby to allow the obtained asphalt mixture to have
excellent preservation stability.
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[0041]
The mixture obtained in the above manner is then taken
out from the mixing apparatus in a state of being maintained
at a temperature of 100-130 C, and the asphalt mixture
according to the present embodiment can thus be produced.
[0042]
In the present embodiment, a bag that comprises a
moisture permeation preventing layer and a thermal fusion
bonding layer is filled with the asphalt mixture obtained in
such a manner, and the thermal fusion bonding layer is then
heated and pressed using a heat sealer or the like so that
the thermal fusion bonding layer is thermally fused and
bonded, whereby the asphalt mixture is enclosed in the bag.
According to the present embodiment, the bag having a
moisture permeation preventing layer is used as a bag for
enclosing the asphalt mixture thereby to reduce the water
amount getting through into the bag (e.g. to reduce the
water amount getting through into the bag to about 0.1-1% or
less), so that the asphalt mixture has excellent
preservation stability. Moreover, the asphalt mixture is
enclosed in the bag that comprises a moisture permeation
preventing layer and a thermal fusion bonding layer in such
a manner, thereby to prevent the alkaline additive material
contained in the asphalt mixture from being deactivated due
to the reaction with water, and the compounding amount of
the alkaline additive material can thus be relatively small.
More specifically, the compounding amount of the alkaline
additive material may preferably be within a range of 100:15
to 100:40 as a weight ratio of "lubricative solidification
material:alkaline additive material."
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[0043]
In the bag that comprises a moisture permeation
preventing layer and a thermal fusion bonding Layer to be
used in the present embodiment, examples of a material that
constitutes the moisture permeation preventing layer include
nylon and ethylene-vinylalcohol copolymer. Examples of a
material that constitutes the thermal fusion bonding layer
include polyolefin. In the present embodiment, the bag that
comprises a moisture permeation preventing layer and a
thermal fusion bonding layer may preferably be a bag that
has a three-layer structure of thermal fusion bonding
layer/moisture permeation preventing layer/thermal fusion
bonding layer, and may particularly preferably be a bag that
has a three-layer structure of polyolefin layer/nylon
layer/polyolefin layer. A base material that constitutes the
bag comprising a moisture permeation preventing layer and a
thermal fusion bonding layer to be used in the present
embodiment (portion other than the moisture permeation
preventing layer and the thermal fusion bonding layer) is
not particularly limited, and examples thereof include paper
and aluminum foil.
[0044]
The asphalt mixture obtained in such a manner may be
put out from the bag comprising a moisture permeation
preventing layer and a thermal fusion bonding layer and used
for pavement construction, for example, and then added
thereto with the hardening accelerator (e.g. water) and
compacted (or otherwise compacted and then added thereto
with the hardening accelerator), and the lubricative
solidification material and alkaline additive material that
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CA 2966073 201.7.3
are contained in the asphalt mixture can thus be subjected
to a saponification reaction or a neutralization reaction
and solidified due to the hardening accelerator thereby to
develop the strength. In particular, the asphalt mixture
according to the present embodiment has an enhanced initial
strength compared with that of a conventional ordinary
temperature mixture packed in a bag, and the strength is
developed at an early stage.
[0045]
qSecond Embodiment
In an alternative embodiment of the present invention,
the mixture to be obtained in the above process may be
configured such that the alkaline additive material is added
thereto, in addition to the hardening accelerator (e.g.
water), when the lubricative solidification material and the
alkaline component are subjected to a saponification
reaction or a neutralization reaction.
[0046]
In this case, the above-described alkaline additive
material may be used as the alkaline additive material to be
added with the hardening accelerator, for example, but it is
particularly preferred to use potassium pyrophosphate.
[0047]
According to the present embodiment, by employing a
configuration in which the alkaline additive material is
added in addition to the hardening accelerator when the
lubricative solidification material and the alkaline
component are subjected to a saponification reaction or a
neutralization reaction, the ratio of the alkaline additive
material to be contained in the asphalt mixture can be
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CA 2966073 2017-05-03
suppressed to a low value thereby to enhance the
preservation stability of the asphalt mixture. For example,
in this case, the ratio of the alkaline additive material in
the asphalt mixture may preferably be within a range of
100:1 to 100:10 as a weight ratio of "lubricative
solidification material: alkaline additive material".
Otherwise, in this case, the alkaline additive material may
not be added at all. Further, in this case, if the ratio of
the alkaline additive material in the asphalt mixture is
suppressed to a low value, then it is possible even to use a
bag that does not have any moisture permeation preventing
layer or a bag that has less sealing property as the bag for
enclosing the asphalt mixture. In addition, the asphalt
mixture according to the present embodiment has an enhanced
initial strength compared with that of a conventional
ordinary temperature mixture packed in a bag, and the
strength is developed at an early stage.
EXAMPLES
[0048]
The present invention will hereinafter be described
with reference to more detailed examples, but the present
invention is not limited to these examples.
[0049]
<Examples 1 to 6>
Each asphalt mixture was obtained by compounding an
aggregate, a straight asphalt, a lubricative solidification
material (trade name "PM400-C" available from MIYOSHI OIL &
FAT CO., LTD.), and an ordinary Portland cement into a twin-
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CA 2966073 2017-05-03
shaft pug mill-type mixer (1 batch: 30 to 60 kg) in this
order and mixing them. During this operation, the heating
temperature for the aggregate was 110-130 C, the heating
temperature for the asphalt was 150-165 C, and other members
were at ordinary temperatures. The lubricative
solidification material (trade name "PM400-C" available from
MIYOSHI OIL & FAT CO., LTD.) used in Examples 1 to 6 has
properties as below:
-component ratio: 4 wt% of palmitic acid, 1 wt% of
stearic acid, 1 wt% of palmitoleic acid, 68 wt% of oleic
acid, 23 wt% of linoleic acid, and 1 wt% of linolenic acid;
-acid value: 194 to 204; and
-iodine value: 95 to 115.
[0050]
In each of Examples 1 to 6, two types of asphalt
mixtures were prepared to have a compounding amount of the
lubricative solidification material to the total of 100 wt%
of the straight asphalt and the lubricative solidification
material as follows:
-compounding amount of the lubricative solidification
material: 5 wt (Example 1);
-compounding amount of the lubricative solidification
material: 10 wt (Example 2);
-compounding amount of the lubricative solidification
material: 15 wt% (Example 3);
-compounding amount of the lubricative solidification
material: 20 wt% (Example 4);
-compounding amount of the lubricative solidification
material: 25 wt% (Example 5); and
-compounding amount of the lubricative solidification
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CA 2966073 2017-05-03
material: 30 wt% (Example 6).
Specifically, two types of mixtures of "ordinary
compounding" and "pervious compounding" were obtained (here
and hereinafter in Example 7 and Comparative Examples 1 to
7). In the "ordinary compounding," an aggregate having the
combined gradation as listed in Table 1 was used as the
aggregate, and the compounding amounts of the aggregate,
straight asphalt, lubricative solidification material and
ordinary Portland cement were those as listed in Table 2. In
the "pervious compounding," an aggregate having the combined
gradation as listed in Table 3 was used as the aggregate,
and the compounding amounts of the aggregate, straight
asphalt, lubricative solidification material and ordinary
Portland cement were those as listed in Table 4.
[0051]
[Table 1]
Table 1
Aggregate for "ordinary compounding"
19.0mm 100.0
13.2mm 97.0
4.75mm 62.8
Passing mass 2.36mm 42.8
percentage (%) 60011 m 25.2
300 m m 16.2
150mm 9.4
75 Mm 6.3
[ 0 0 5 2
[Table 2]
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CA 2966073 2017-05-03
Table 2
Composition for "ordinary compounding"
Example 1 Example 2 Example 3 Example 4 Example 5, Example 6
Compounding amount of lubricative solidification
material (wt% to total 100 wt% of straight asphalt 5 10 15 20
25 30
and lubricative solidification material)
Aggregate (parts by weight) 100.0 100.0 100.0 100.0 100.0
100.0
Straight asphalt (parts by weight) 5.55 5.28 5.01 4.74 4.46
4.18
Lubricative solidification material (parts by weight) 0.29 0.59 0.88
1.18 1.49 1.79
Ordinary Portland cement (parts by weight) 0.44 0.88 1.33 1.78
2.23 269
[0053]
[Table 3]
Table 3
Aggregate for "pervious compounding"
19.0mm 100.0
13.2mm 97.9
4.75mm 30.1
Passing mass 2.36mm 18.0
percentage (%) 60011 m 10.5
300 Mm 7.6
150 /I m 6.2
75 kt m 4.2
[0054]
[Table 4]
Table 4 =
Composition for "pervious compounding"
Example 1 Example 2 Example 3 Example 4 Example 5 Example 6
Compounding amount of lubricative solidification
material (wt% to total 100 wt% of straight asphalt 5 10 15 20
25 30
and lubricative solidification material)
Aggregate (parts by weight) 100.0 100.0 100.0 100.0 100.0
100.0
Straight asphalt (parts by weight) 4.34 4.13 3.92 3.70 3.49
3.27
Lubricative solidification material (parts by weight) 0.23 0.46 0.69
0.93 1.16 1.40
Ordinary Portland cement (parts by weight) 0.34 0.69 1.04 1.39
1.74 2.10
[0055]
<Example 7>
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CA 2966073 2017-05-03
An asphalt mixture was obtained in the same manner as
in Example 4 except that a lubricative solidification
material (trade name "PM810" available from MIYOSHI OIL &
FAT CO., LTD.) was used as substitute for the lubricative
solidification material (trade name "PM400-C" available from
MIYOSHI OIL & FAT CO., LTD). In Example 7, therefore, the
compounding amount of the lubricative solidification
material was 20 wt% to the total of 100 wt% of the straight
asphalt and the lubricative solidification material.
The lubricative solidification material (trade name
"PM810" available from MIYOSHI OIL & FAT CO., LTD.) used in
Example 7 has properties as below:
-component ratio: 2 wt% of myristic acid, 5 wt% of
palmitic acid, 1 wt% of stearic acid, 2 wt% of myristoleic
acid, 8 wt% of palmitoleic acid, 71 wt% of oleic acid, 8 wt%
of linoleic acid, and 1 wt% of linolenic acid;
-acid value: 198 to 208; and
-iodine value: 86 to94.
[0056]
<Comparative Examples 1 to 6>
An asphalt mixture according to each of Comparative
Examples 1 to 6 was obtained with the same compounding ratio
as in each of Examples 1 to 6 except that a lubricative
solidification material (tall oil fatty acid, trade name
"HARTALL FA-1" available from Harima Chemicals Group, Inc.)
was used as substitute for the lubricative solidification
material (trade name "PM400-C" available from MIYOSHI OIL &
FAT CO., LTD). The tall oil fatty acid (trade name "HARTALL
FA-1" available from Harima Chemicals Group, Inc.) used in
Comparative Examples 1 to 6 has properties as below:
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CA 2966073 2017-05-03
-"fatty acid:resin acid"=98.5:1.5 (weight ratio);
-unsaponifiable matter content: 2.0 wt%;
-component ratio of fatty acid: 1-3 wt% of palmitic
acid, 1-3 wt% of stearic acid, 40-50 wt% of oleic acid, and
35-45 wt% of linoleic acid;
-type of resin acid: rosin; and
-acid value: 194 mgKOH/g.
In each of Comparative Examples 1 to 6, the
compounding amount of the lubricative solidification
material to the total of 100 wt% of the straight asphalt and
the lubricative solidification material was as follows:
-compounding amount of the lubricative solidification
material: 5 wt% (Comparative Example 1);
-compounding amount of the lubricative solidification
material: 10 wt% (Comparative Example 2);
-compounding amount of the lubricative solidification
material: 15 wt% (Comparative Example 3);
-compounding amount of the lubricative solidification
material: 20 wt% (Comparative Example 4);
-compounding amount of the lubricative solidification
material: 25 wt% (Comparative Example 5); and
-compounding amount of the lubricative solidification
material: 30 wt% (Comparative Example 6).
[0057]
<Comparative Example 7>
An asphalt mixture was obtained in the same manner as
in Example 1 except that the lubricative solidification
material (trade name "PM400-C" available from MIYOSHI OIL &
FAT CO., LTD.) and ordinary Portland cement were not
compounded. In Comparative Example 7, the "ordinary
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CA 2966073 2017-05-03
compounding" involved 100 parts by weight of aggregate and
5.82 parts by weight of straight asphalt, and the "pervious
compounding" involved 100 parts by weight of aggregate and
4.55 parts by weight of straight asphalt.
[0058]
<Evaluation of Asphalt Mixtures of Examples 1 to 7 and
Comparative Examples 1 to 7>
The asphalt mixtures of Examples 1 to 7 and
Comparative Examples 1 to 7 obtained in the above manner
were each put into a mold (formwork) heated to the
compaction temperature and water was then added to perform
compaction (50 times for each of both surfaces). After being
cured for 7 days under the condition of a temperature of
20 C and a humidity of 60%, test pieces were obtained. Two
types of test pieces were obtained, one type using the
"ordinary compounding," the other using the "pervious
compounding." The test pieces thus obtained were used to
perform the following wheel tracking test, twisting test,
and bending test.
[0059]
(Wheel Tracking Test)
For the test pieces using the "ordinary compounding,"
the wheel tracking test was performed at a testing
temperature of 60 C in accordance with "3-7-1" and "3-7-3"
of the "Pavement Testing Method Handbook" ("Hosou Shikenhou
Binran" in Japanese) (published by Japan Road Association,
November 1988) to obtain dynamic stability (times/mm). As
the value of dynamic stability (times/mm) increases, the
strength also increases to mitigate the occurrence of
rutting, which may be preferred. Results are listed in Table
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CA 2966073 2017-05-03
=
5. In Table 5, the results of each of the examples and
comparative examples are listed in association with the type
of the compounded lubricative solidification material and
the compounding amount of the lubricative solidification
material (here and hereinafter in Tables 6 and 7).
[0060]
[Table 5]
Table 5
Compounding amount of lubricative solidification material (wt% to total 100
wt% of
straight asphalt and lubricative solidification material)
0 5 10 15 20 25 30
PM400¨C (68 wt% of oleic acid)
800 1,500 4,000 6,000 9,000 12,000
(Examples 1 to 6)
Dynamic
PM810 (71 wt% of oleic acid)
stability 9,000
(Example 7)
(times/mm)
Tall oil fatty acid (40 to 50 wt%
of oleic acid) (Comparative 500 600 880 1,400 1,900 4,000
7,000
Examples 1 to 7)
[0061]
(Twisting Test)
For the test pieces using the "pervious compounding,"
the twisting test was performed at a testing temperature of
50 C for 2 hours of the testing time in accordance with the
"Measuring Method using a Twisted Aggregate Scattering
Tester for Obtaining a Twisted Aggregate Scattering Value,
Supplementary Volume of Pavement Performance Evaluation
Method" to obtain an aggregate scattering ratio (%) of the
aggregate from the test pieces. When a test piece
disintegrated before the testing time of 2 hours passed, the
disintegration time was obtained. In the twisting test, as
the aggregate scattering ratio decreases, or the time before
the test piece disintegrates increases, the durability to
- 29 -
CA 2966073 2017-05-03
torque becomes high, which may be preferred. Results are
listed in Table 6.
[0062]
[Table 6]
Table 6
Compounding amount of lubricative solidification material (wt% to total 100
wt% of
straight asphalt and lubricative solidification material)
0 5 10 15 20 25 30
Disinteg- Disinteg-
PM400-C (68 wt% of oleic acid) ration ration
25.2 6.0 3.4 1.2
(Examples 1 to 6) after 40 after 60
mm. mm.
Aggregate
Pli.4810 (71 wt% of oleic acid)
scattering 5.6 .
ratio (%) (Example 7)
Tall oil fatty acid (40 to 50
Disinteg- Disinteg- Disinteg- Disinteg-
rationwt% ration ration ration
of oleic acid) (Comparative 10.8 6.4 2.8
after 25 after 30 after 40 after 100
Examples I to 7)
min, min. min. iron.
[0063]
(Bending Test)
For the test pieces using the "ordinary compounding,"
the bending test was performed at a testing temperature of
-10 C in accordance with the "Pavement Investigation/Testing
Method Handbook B005" ("Hosou Chosa/Shikenhou Binran" in
Japanese) to obtain breaking strain (x1073 mm/mm). In the
bending test, as the breaking strain increases, the
flexibility becomes excellent to mitigate the occurrence of
cracks, which may be preferred. Results are listed in Table
7.
[0064]
[Table 7]
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CA 2966073 2017-05-03
Table 7
Compounding amount of lubricative solidification material (wt% to total 100
wt% of
straight asphalt and lubricative solidification material)
0 5 10 15 20 25 30
PM400¨C (68 wt% of oleic acid)
2.6 2.9 34 3.8 4.1 4.3
(Examples 1 to 6)
Breaking
strain PM810 (71 virt% of oleic acid) 4/
(00 (Example 7)
mm/mm)
Tall oil fatty acid (40 to 50 vitt%
of oleic acid) (Comparative 2.3 2.2 2.3 2.4 2.3 2.3 2.4
Examples 1 to 7)
[0065]
<Evaluation of Examples 1 to 7 and Comparative Examples 1 to
7>
As found from Tables 5 to 7, it can be confirmed that,
when the lubricative solidification materials ("PM400-C" and
"PM810") containing oleic acid at a ratio of 60 to 85 wt%
are used, the test pieces excellent in the dynamic stability
(wheel tracking test), durability to torque (twisting test),
and breaking strain (bending test) are obtained, and the
effect of improving the strength, durability and flexibility
is high, compared with when using the same additive amount
of the lubricative solidification materials (tall oil fatty
acid) which contain oleic acid at a ratio of 40 to 50 wt%.
Regarding "PM810", only a test result in which the
compounding amount of the lubricative solidification
material is 20 wt% was shown, however, results when changing
the compounding amount showed a same tendency as the results
when "PM400-C" was used.
[0066]
<Example 8>
An asphalt mixture was obtained in the same manner as
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CA 2966073 2017-05-03
in Example I except that the compounding amount of the
lubricative solidification material (trade name "PM400-C"
available from MIYOSHI OIL & FAT CO., LTD.) was 45 wt% to
the total of 100 wt% of the straight asphalt and the
lubricative solidification material. In Example 8, 100 parts
by weight of aggregate having the combined gradation as
listed in Table 1, 3.22 parts by weight of straight asphalt,
2.64 parts by weight of lubricative solidification material,
and 0.66 parts by weight of ordinary Portland cement were
used. In Example 8, only the "ordinary compounding" was
prepared, and the "pervious compounding" was not prepared
(here and hereinafter in Example 9 and Comparative Example
8).
[0067]
<Example 9>
An asphalt mixture was obtained in the same manner as
in Example 8 except that a lubricative solidification
material (trade name "PM810" available from MIYOSHI OIL &
FAT CO., LTD.) was used as substitute for the lubricative
solidification material (trade name "PM400-C" available from
MIYOSHI OIL & FAT CO., LTD).
[0068]
<Comparative Example 8>
An asphalt mixture was obtained in the same manner as
in Example 8 except that a lubricative solidification
material (tall oil fatty acid, trade name "HARTALL FA-1"
available from Harima Chemicals Group, Inc.) was used as
substitute for the lubricative solidification material
(trade name "PM400-C" available from MIYOSHI OIL & FAT CO.,
LTD).
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CA 2966073 2017-05-03
4 - =
[0069]
<Evaluation of Asphalt Mixtures of Examples 8 and 9 and
Comparative Example 8>
The asphalt mixtures of Examples 8 and 9 and
Comparative Example 8 obtained in the above manner were each
put into a mold (formwork) heated to the compaction
temperature and water was then added to perform compaction
(50 times for each of both surfaces). After being cured,
test pieces were obtained. The test pieces Included Test
Pieces A obtained after curing for 1 hour under the
condition of a temperature of 20 C and a humidity of 60% and
Test Pieces B obtained after curing for 7 days under the
condition of a temperature of 20 C and a humidity of 60%.
The test pieces thus obtained were used to perform the
following measurement of Marshal stability.
[0070]
(Marshall Stability)
Measurement of Marshall stability was conducted using
the obtained Test Pieces A and B. The measurement of
Marshall stability was performed at 20 C for Test Pieces A
(curing time: 1 hour) and performed at 60 C for Test Pieces
B (curing time: 7 days). Results are listed in Table 8. As
the value of Marshall stability (kN) increases, it can be
determined that a stable and high-strength test piece is
obtained at an earlier stage, which may be preferred.
[0071]
[Table 8]
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CA 2966073 2017-05-03
=
Table 8
Marshall stability (kN)
Curing for 1 hour Curing for 7 days
(Testing temperature (Testing temperature
20 C) 60t)
PM400¨C (68 wt% of
5.6 12.8
oleic acid) (Example 8)
PM810 (71 wt% of oleic
5.7 14.1
acid) (Example 9)
Tall oil fatty acid (40 to
50 wt% of oleic acid) 5.3 11.4
(Comparative Example 8)
[0072]
<Evaluation of Examples 8 and 9 and Comparative Example 8>
As found from Table 8, it can be confirmed that, when
the lubricative solidification materials ("PM400-C" and
"PM810") containing oleic acid at a ratio of 60 to 85 wt%
are used, the value of Marshall stability is high and the
strength can be developed at an earlier stage compared with
when using the same additive amount of the lubricative
solidification materials (tall oil fatty acid) which contain
oleic acid at a ratio of 40 to 50 wt%.
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