U.S. patent application number 13/704755 was filed with the patent office on 2013-04-11 for additive for reclamation of asphalt, reclaimed asphalt pavement material containing same, modified asphalt, and asphalt pavement material containing same.
The applicant listed for this patent is Yukio Kusano. Invention is credited to Yukio Kusano.
Application Number | 20130090415 13/704755 |
Document ID | / |
Family ID | 45347990 |
Filed Date | 2013-04-11 |
United States Patent
Application |
20130090415 |
Kind Code |
A1 |
Kusano; Yukio |
April 11, 2013 |
ADDITIVE FOR RECLAMATION OF ASPHALT, RECLAIMED ASPHALT PAVEMENT
MATERIAL CONTAINING SAME, MODIFIED ASPHALT, AND ASPHALT PAVEMENT
MATERIAL CONTAINING SAME
Abstract
An additive for reclaiming asphalt of the present invention,
which is obtained by adding straight asphalt to a mixture of a
waste animal or vegetable oil and a waste mineral oil having a
kinematic viscosity at 60.degree. C. of 10 mm.sup.2/s to 40
mm.sup.2/s, mixing the materials, and heating the resultant mixture
to remove an aromatic component. The additive for reclaiming
asphalt can restore the physical properties of a deteriorated
asphalt component to the same or greater extent than that of a
conventional additive for reclaiming asphalt, and the additive has
low content of components that may affect the environment or
humans, and high fluidity at room temperature, and is available at
an extremely low cost.
Inventors: |
Kusano; Yukio; (Miyagi,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Kusano; Yukio |
Miyagi |
|
JP |
|
|
Family ID: |
45347990 |
Appl. No.: |
13/704755 |
Filed: |
May 12, 2011 |
PCT Filed: |
May 12, 2011 |
PCT NO: |
PCT/JP2011/060963 |
371 Date: |
December 17, 2012 |
Current U.S.
Class: |
524/71 ;
106/246 |
Current CPC
Class: |
C08L 91/06 20130101;
C09D 7/63 20180101; C08L 101/00 20130101; C08L 2555/80 20130101;
C08L 2555/64 20130101; C09D 7/65 20180101; C08L 2555/22 20130101;
C08L 99/00 20130101; C08L 2555/34 20130101; C08L 95/00 20130101;
C08L 2555/74 20130101; C08L 2555/32 20130101; C08L 91/00 20130101;
C08L 25/06 20130101; C08L 95/00 20130101; C08L 91/00 20130101; C08L
99/00 20130101; C08L 95/00 20130101; C08L 25/06 20130101; C08L
99/00 20130101; C08L 95/00 20130101; C08L 25/06 20130101; C08L
91/00 20130101 |
Class at
Publication: |
524/71 ;
106/246 |
International
Class: |
C09D 7/12 20060101
C09D007/12 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 18, 2010 |
JP |
2010139114 |
Claims
1. An additive for reclaiming asphalt, obtained by adding straight
asphalt to a mixture of a waste animal or vegetable oil and a waste
mineral oil having a kinematic viscosity at 60.degree. C. of 10
mm.sup.2/s to 40 mm.sup.2/s, mixing the materials, and heating the
resultant mixture to remove an aromatic component.
2. A reclaimed asphalt pavement material, comprising the additive
for reclaiming asphalt according to claim 1 added to an asphalt
pavement waste or a mixture of a fresh aggregate and an asphalt
pavement waste.
3. A modified asphalt, obtained by adding, to molten straight
asphalt, a xerogel-like amorphous resin, which is obtained by
dissolving an amorphous resin with an organic solvent capable of
dissolving the amorphous resin to provide a gel- or dough-like
amorphous resin in a saturated state, immersing the resin in
alcohol to remove the organic solvent, and drying the remainder,
together with a waste animal or vegetable oil, and mixing the
materials.
4. A modified asphalt, obtained by adding, to molten straight
asphalt, a product, which is obtained by dissolving an amorphous
resin with an organic solvent capable of dissolving the amorphous
resin to provide a gel- or dough-like amorphous resin in a
saturated state, and heating the resin to melt the resin, together
with a waste animal or vegetable oil, and mixing the materials,
wherein a content of the gel- or dough-like amorphous resin in the
modified asphalt is 70 wt % to 90 wt %.
5. An asphalt pavement material, comprising the modified asphalt
according to claim 3 added to a fresh aggregate, an asphalt
pavement waste, or a mixture of a fresh aggregate and an asphalt
pavement waste.
6. An asphalt pavement material, comprising the modified asphalt
according to claim 4 added to a fresh aggregate, an asphalt
pavement waste, or a mixture of a fresh aggregate and an asphalt
pavement waste.
Description
TECHNICAL FIELD
[0001] The present invention relates to an additive for reclaiming
asphalt, a reclaimed asphalt pavement material that contains same,
a modified asphalt, and an asphalt pavement material that contains
same.
BACKGROUND ART
[0002] The total amount of production of asphalt mixtures is
decreasing each year after reaching a peak in 1989 (see Non Patent
Document 1). This is because the length of roads paved with asphalt
in Japan has already reached 1,190,000 km and hence the number of
roads to be newly constructed is reducing. Meanwhile, the
reclamation rate of asphalt pavement waste, which was 7.6% in 1989,
continues to increase abruptly, reaching 73.1% in 2008. This trend
is expected to become stronger and stronger in the future as
well.
[0003] Two methods each involving restoring the physical properties
of an asphalt component that has deteriorated over time with an
additive for reclaiming asphalt have been known for the reclamation
of asphalt pavement waste (see Non Patent Document 2). One of the
methods is a road-surface recycling method (remix system and repave
system) but this is seldom adopted in Japan. The other is a plant
recycling pavement method (plant mix system) which has gone
mainstream in Japan. Several kinds of products (each using, for
example, a semi-refined oil at the time of petroleum refining as a
main raw material) have been commercially available as additives
for reclaiming asphalt that can be used in the plant recycling
pavement method. However, the products are not only expensive, but
the products have high viscosities (are greasy) at room temperature
and hence need to be heated to about 70.degree. C. to 80.degree. C.
at all times. Accordingly, it is inconvenient to handle the
products and heat source costs are required. In addition, concerns
are raised about the effect of the products on the environment and
humans because the products each contain large amounts of aromatic
components.
[0004] In view of the foregoing, for example, an additive for
reclaiming asphalt obtained by blending a mineral oil having a
kinematic viscosity at 60.degree. C. of 100 to 1,000 mm.sup.2/s,
and a fat, the additive having a kinematic viscosity at 60.degree.
C. of 20 to 300 mm.sup.2/s and a flash point of 220.degree. C. or
more (see Patent Document 1), and an additive for reclaiming
asphalt obtained by blending a mineral oil having a kinematic
viscosity at 40.degree. C. of 300 to 900 mm.sup.2/s and a
polycyclic aromatic content of less than 3 wt %, and a fat, the
additive having a kinematic viscosity at 40.degree. C. of 40 to 400
mm.sup.2/s, a polycyclic aromatic content of less than 3 wt % and a
flash point of 220.degree. C. or more (see Patent Document 2), have
been proposed. However, the high-viscosity mineral oils used in
Patent Documents 1 and 2 are expensive because the oils are
generally refined to a high degree, resulting in the prices of the
products also become high.
[0005] In addition, modified asphalt obtained by adding plastic,
rubber, or the like to straight asphalt to improve the properties
of the asphalt has been known. For example, Patent Document 3
proposes a modified asphalt formed of asphalt, a waste plastic such
as a waste polystyrene, and a waste oil containing an engine oil as
a main component. An upper limit for the content of the waste
plastic in the modified asphalt disclosed in Patent Document 3 is
set to 40 wt %. This is because when the waste plastic is added at
a content in excess of 40 wt %, curing starts immediately after the
mixing of the materials and hence the resultant product cannot be
used as a modified asphalt (see Comparative Example of Patent
Document 3). In the industry, however, a modified asphalt blended
with an additionally large amount of plastic, rubber, or the like
is in demand in expectation of further improvements in the
properties of asphalt.
PRIOR ART
Patent Document
[0006] [Patent Document 1] Japanese Patent Laid-Open No.
2005-154465 [0007] [Patent Document 2] Japanese Patent Laid-Open
No. 2005-154464 [0008] [Patent Document 3] Japanese Patent
Laid-Open No. 2006-143954
Non Patent Document
[0008] [0009] [Non Patent Document 1] "The Annual Statistical
Report of Asphalt Mixtures 2008," Japan Asphalt Mixture Association
eds. [0010] [Non Patent Document 2] "Manual for Pavement
Recycling," Japan Road Association eds., February 2004, p. 12, p.
207
SUMMARY OF INVENTION
Technical Problem
[0011] Therefore, the present invention has been made to solve the
above-mentioned problems, and an object of the present invention is
to provide an additive for reclaiming asphalt which restores the
physical properties of a deteriorated asphalt component to the same
extent as that of a conventional additive for reclaiming asphalt,
but has low content of components that may affect the environment
or humans, has high fluidity at room temperature, and is available
at an extremely low cost.
[0012] In addition, the present invention has been made to solve
the above-mentioned problems, and an object of the present
invention is to provide a modified asphalt which can be blended
with a large amount of a resin component and which shows improved
properties of asphalt.
Solution to Problem
[0013] An additive for reclaiming asphalt according to the present
invention is obtained by adding straight asphalt to a mixture of a
waste animal or vegetable oil and a waste mineral oil having a
kinematic viscosity at 60.degree. C. of 10 to 40 mm.sup.2/s, mixing
the materials, and heating the resultant mixture to remove an
aromatic component.
[0014] In addition, the present invention is a reclaimed asphalt
pavement material obtained by adding the above-mentioned additive
for reclaiming asphalt to an asphalt pavement waste or a mixture of
a fresh aggregate and an asphalt pavement waste.
[0015] In addition, a modified asphalt according to the present
invention is obtained by adding, to molten straight asphalt, a
xerogel-like amorphous resin, which is obtained by dissolving an
amorphous resin with an organic solvent capable of dissolving the
amorphous resin to provide a gel- or dough-like amorphous resin in
a saturated state, immersing the resin in alcohol to remove the
organic solvent, and drying the remainder, together with a waste
animal or vegetable oil, and mixing the materials.
[0016] In addition, a modified asphalt according to the present
invention is obtained by adding, to molten straight asphalt, a
product, which is obtained by dissolving an amorphous resin with an
organic solvent capable of dissolving the amorphous resin to
provide a gel- or dough-like amorphous resin in a saturated state,
and heating the resin to melt the resin, together with a waste
animal or vegetable oil, and mixing the materials, wherein the
content of the gel- or dough-like amorphous resin in the modified
asphalt is 70 wt % to 90 wt %.
[0017] Further, the present invention is an asphalt pavement
material where the above-mentioned modified asphalt is added to a
fresh aggregate, an asphalt pavement waste, or a mixture of a fresh
aggregate and an asphalt pavement waste.
Advantageous Effects of the Invention
[0018] According to the present invention, it is possible to
provide an additive for reclaiming asphalt which restores the
physical properties of a deteriorated asphalt component to the same
extent as that of a conventional additive for reclaiming asphalt,
has low content of components that may affect the environment or
humans, has high fluidity at room temperature, and is available at
an extremely low cost.
[0019] Further, according to the present invention, it is possible
to provide a modified asphalt which can be blended with a large
amount of a resin component and which shows improved properties of
asphalt.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1 is a photograph showing a surface state after a wheel
tracking test for the reclaimed asphalt pavement material obtained
in Example 15.
[0021] FIG. 2 is a photograph showing a surface state after a wheel
tracking test for the asphalt pavement material obtained in
Comparative Example 8.
[0022] FIG. 3 is a photograph showing a surface state after a wheel
tracking test for the asphalt pavement material obtained in
Comparative Example 9.
[0023] FIG. 4 is a photograph showing a fracture cross-section of
the reclaimed asphalt pavement material obtained in Example 15.
DESCRIPTION OF EMBODIMENTS
[0024] Hereinafter, the present invention will be described in
detail.
[0025] First, an additive for reclaiming asphalt of the present
invention is described.
[0026] In industry, compensating for aromatic components in asphalt
lost by its deterioration has heretofore been considered most
important in restoring the physical properties of the asphalt, and
hence most of the conventional additives for reclaiming asphalt
have each contained a large amount of an aromatic component.
However, the inventor of the present invention has judged from
previous experiences that the aromatic component is not useful in
restoring the physical properties of asphalt because most of the
component evaporates at the time of heating and mixing. In view of
the foregoing, the inventor of the present invention, after
conducting intensive studies and development for restoring the
physical properties of asphalt through the control of the softening
and dispersion of the asphalt, has found that that a product
obtained by dissolving straight asphalt in a mixture of a waste
animal or vegetable oil and a waste mineral oil, and removing
aromatic components from the solution is useful, to complete the
present invention.
[0027] That is, an additive for reclaiming asphalt of the present
invention is obtained by adding straight asphalt to a mixture of a
waste animal or vegetable oil and a waste mineral oil having a
kinematic viscosity at 60.degree. C. of 10 mm.sup.2/s to 40
mm.sup.2/s, mixing the materials, and heating the resultant mixture
to remove aromatic components. A temperature for the heating may be
a temperature at which the aromatic components mainly incorporated
into the waste mineral oil and the straight asphalt can be removed,
and is preferably 230.degree. C. to 250.degree. C.
[0028] A mixing ratio of the waste animal or vegetable oil to the
waste mineral oil having a kinematic viscosity at 60.degree. C. of
10 mm.sup.2/s to 40 mm.sup.2/s is preferably 1:9 to 99.1:0.1, more
preferably 1:9 to 9:1, most preferably 5:5 to 9:1 on a weight basis
from the viewpoint of balance between the softening of the straight
asphalt from the waste mineral oil and the dispersibility of the
straight asphalt from the waste animal or vegetable oil. The mixing
ratio of the waste animal or vegetable oil is desirably increased
to raise the flash point of the additive in order to further
improve safety at the time of its production. In addition, the
addition amount of the straight asphalt is preferably such an
amount that the additive for reclaiming asphalt has a kinematic
viscosity at 60.degree. C. of 80 mm.sup.2/s to 200 mm.sup.2/s, and
is typically 3 wt % to 30 wt % with respect to the additive for
reclaiming asphalt, though the preferred amount varies depending on
the degree of penetration of the straight asphalt. Straight
asphalts having a penetration degree of 20 to 80 are preferably
used. Of those, straight asphalt having a penetration degree of 20
to 40 is desirable because the kinematic viscosity can be adjusted
to a desired level with a small addition amount.
[0029] A waste vegetable oil, or waste animal oil discarded from
ordinary households, eateries, or the like can be used as the waste
animal or vegetable oil in the present invention, and such waste
animal or vegetable oil typically has a kinematic viscosity at
60.degree. C. of 60 mm.sup.2/s to 150 mm.sup.2/s.
[0030] The waste mineral oil in the present invention may be any
waste mineral oils having a kinematic viscosity at 60.degree. C. of
10 mm.sup.2/s to 40 mm.sup.2/s, and waste lubricating oil, waste
engine oil, or the like discarded from gas stations or the like can
be used. In addition, a waste animal or vegetable oil and a waste
mineral oil treated in advance with a filtering apparatus such as a
strainer in order to remove foreign matter in the waste animal or
vegetable oil and the waste mineral oil are preferably used. It
should be noted that the kinematic viscosity is a value determined
according to JIS K2283.
[0031] The additive for reclaiming asphalt of the present invention
has an excellent ability to restore the physical properties of a
deteriorated asphalt component, has low content of aromatic
components that may affect the environment or humans, and has such
a high fluidity at room temperature that the additive can be
directly used as an additive in a plant mix system without being
heated. In addition, the additive is available at an extremely low
cost because the additive utilizes waste products. Further, the
additive for reclaiming asphalt of the present invention has an
advantage that the physical properties of the deteriorated asphalt
component can be restored with a smaller addition amount than that
of a conventional additive for reclaiming asphalt.
[0032] A reclaimed asphalt pavement material of the present
invention is obtained by adding the additive for reclaiming asphalt
to an asphalt pavement waste or a mixture of a fresh aggregate and
the asphalt pavement waste, and melting and mixing the materials
under temperatures of 150.degree. C. to 180.degree. C. In the
present invention, the additive for reclaiming asphalt and a
modified asphalt that is described later may be used in
combination. When the modified asphalt is used in combination, the
melting and mixing can be performed under temperatures of
150.degree. C. to 170.degree. C.
[0033] Here, examples of the asphalt pavement waste include
products (recycled aggregates) obtained by pulverizing asphalt
pavement waste generated during various types of construction (such
as road pavement construction and underground piping construction).
The amount of the deteriorated asphalt in the asphalt pavement
waste is typically 2 wt % to 6 wt %. The asphalt pavement waste
preferably has a penetration degree of 20 or more in consideration
of ease of reclamation. It should be noted that the penetration
degree is a value determined according to JIS K2207 (1996) at
25.degree. C.
[0034] The addition amount of the additive for reclaiming asphalt
with respect to the asphalt pavement waste or the mixture of the
fresh aggregate and the asphalt pavement waste is an amount needed
to restore the physical properties (such as penetration degree and
stability) of the asphalt pavement waste to desired values, and may
be appropriately determined within the range of 1 wt % to 6 wt %
with respect to the deteriorated asphalt in the asphalt pavement
waste or the mixture of the fresh aggregate and the asphalt
pavement waste.
[0035] Conventionally known aggregates including natural aggregates
such as size-5, 6, or 7 single-sized crushed stone, coarse sand,
fine sand, and screenings, and artificial aggregates can be used as
the fresh aggregate.
[0036] Next, a modified asphalt of the present invention will be
described.
[0037] The modified asphalt of the present invention is obtained by
adding, to straight asphalt melted by being heated (typically
heated to about 80.degree. C. to 100.degree. C.), a xerogel-like
amorphous resin, or a gel- or dough-like amorphous resin melted by
being heated together with a waste animal or vegetable oil, and
mixing the materials. While the modified asphalt disclosed in
Patent Document 3 can be blended with only up to 40 wt % of a resin
component, the modified asphalt of the present invention can be
blended with up to 90 wt % of the xerogel-like amorphous resin, or
the gel- or dough-like amorphous resin as a resin component. The
inventor of the present invention has experimentally experienced
the fact that a uniform mixture cannot be obtained even when the
straight asphalt, the waste animal or vegetable oil, and a large
amount of an amorphous resin (such as a polystyrene or a polyvinyl
chloride) are stirred and mixed at high temperature for a long
time. The inventor of the present invention felt that this may be
because the cohesive energy of the amorphous resin is so large that
the uniform mixing cannot be performed, and attempted to blend the
amorphous resin in a state of reduced cohesive energy. As a result,
the inventor surprisingly found that the gel- or dough-like
amorphous resin can be blended at 70 wt % to 90 wt % into
themodifiedasphalt and that the xerogel-like amorphous resin can be
blended at 1 wt % to 90 wt % into the modified asphalt.
[0038] The gel- or dough-like amorphous resin in the present
invention is obtained by gradually adding, to a proper organic
solvent (such as a thinner, toluene, benzene, acetone, ethyl
acetate, cyclohexanone, 2-butanone, white kerosene, or a mixture
thereof) capable of dissolving an amorphous resin such as a
polystyrene, a polyvinyl chloride, an ABS resin, or an acrylic
resin, the amorphous resin at a content in the range of 100 wt % to
250 wt % to dissolve the resin, thereby bringing the resin into a
saturated state. In particular, a mixed organic solvent containing
ethyl acetate and white kerosene at a volume ratio of 0.5 to 4:9.5
to 6 is preferably used for the dissolution of the polystyrene, a
mixed organic solvent containing cyclohexanone and white kerosene
at a volume ratio of 0.5 to 4:9.5 to 6 is preferably used for the
dissolution of the polyvinyl chloride, and a mixed organic solvent
containing 2-butanone and white kerosene at a volume ratio of 0.5
to 4:9.5 to 6 is preferably used for the dissolution of the ABS
resin. Such gel- or dough-like amorphous resin is uniformly mixed
with the straight asphalt when the waste animal or vegetable oil is
used as a dispersant because the resin is in a state of reduced
cohesive energy as a result of the occurrence of a molecular shift.
It should be noted that a blending amount of the gel- or dough-like
amorphous resin of less than 70 wt % is not desirable because
curing starts in a relatively short time period. A blending amount
of the gel- or dough-like amorphous resin in excess of 90 wt % is
also not desirable because the properties of the amorphous resin
become so strong that the resin tends to solidify, which results in
remarkably poor workability.
[0039] In addition, the xerogel-like amorphous resin in the present
invention is obtained by immersing the gel- or dough-like amorphous
resin in alcohol (such as methyl alcohol, octanol, and a mixture
thereof) to remove the organic solvent remaining in the gel- or
dough-like amorphous resin, and drying the remainder. Such
xerogel-like amorphous resin can be uniformly mixed with the
straight asphalt at a blending ratio as wide as 1 wt % to 90 wt %
because the resin shows extremely high compatibility with the
straight asphalt when the waste animal or vegetable oil is used as
a dispersant. It should be noted that there is no need to heat and
melt the xerogel-like amorphous resin in advance at the time of
mixing.
[0040] Straight asphalt having a penetration degree of 20 to 80 is
preferably used.
[0041] The modified asphalt of the present invention can provide an
asphalt pavement material excellent in mechanical properties such
as stability because the blending amount of the resin component can
be increased. Further, the modified asphalt whose blending amount
of the xerogel-like amorphous resin, or the gel- or dough-like
amorphous resin is set to 70 wt % to 90 wt % has an advantage that
the modified asphalt clings to very little production equipment
such as mixers or conveying machines such as dump trucks. Further,
when a conventional asphalt pavement material is used, the asphalt
pavement material cools during its transport from an asphalt
mixture factory to a construction site, with the result that its
workability is impaired. However, an asphalt pavement material to
which the modified asphalt of the present invention is added barely
causes such problems because of its high heat-retaining
property.
[0042] An asphalt pavement material of the present invention is
obtained by adding the modified asphalt to a fresh aggregate, an
asphalt pavement waste, or a mixture of a fresh aggregate and
asphalt pavement waste, and melting and mixing the materials under
temperatures of 155.degree. C. to 170.degree. C. The addition
amount of the modified asphalt with respect to the fresh aggregate
may be appropriately determined within such a range that the amount
of the modified asphalt in the asphalt pavement material to be
obtained is 2 wt % to 8 wt %. In addition, the addition amount of
the modified asphalt with respect to the asphalt pavement waste or
the mixture of the fresh aggregate and the asphalt pavement waste
may be appropriately determined within the range of 1 wt % to 45 wt
% with respect to the deteriorated asphalt in the asphalt pavement
waste or the mixture of the fresh aggregate and the asphalt
pavement waste. The asphalt pavement material of the present
invention may be further blended with straight asphalt as required.
The melt-mixing temperature and compaction temperature of the
asphalt pavement material of the present invention can each be
lowered by about 20.degree. C. as compared with that of a
commercially available dense-graded asphalt mixture. In addition,
the melt-mixing temperature and compaction temperature of the
asphalt pavement material can each be lowered by about 30.degree.
C. as compared with that of a commercially available blown asphalt
mixture. Accordingly, energy consumption needed for production of
the asphalt pavement material and carbon dioxide emissions can be
curtailed.
[0043] The same products as those used in the additive for
reclaiming asphalt can be used as the fresh aggregate and the
asphalt pavement waste in the present invention.
[0044] In addition, the asphalt pavement material of the present
invention may be further blended with any one of fillers such as
silica, talc, calcium hydroxide, calcium carbonate, various
minerals, and glass waste in addition to the above-mentioned
components. A preferred blending ratio of the filler is 35 wt % to
55 wt % with respect to the entirety of the asphalt pavement
material. Since the modified asphalt of the present invention is
blended with the amorphous resin, its bonding force with the
aggregate or the filler such as glass waste is increased and hence
the scattering of the aggregate, the glass waste, or the like
toward a paved surface can be suppressed.
[0045] The additive for reclaiming asphalt of the present invention
may be in a solid and in which the additive for reclaiming asphalt
is taken in the xerogel-like amorphous resin obtained as described
above. The solid additive for reclaiming asphalt is obtained by
heating the additive for reclaiming asphalt to 120.degree. C. to
210.degree. C., adding the amorphous resin to the heated additive,
mixing the materials, pouring the mixture into a mold having a
predetermined shape and then cooling and solidifying the mixture. A
preferred addition amount of the xerogel-like amorphous resin is 40
wt % to 90 wt % with respect to the solid additive for reclaiming
asphalt. When the addition amount of the xerogel-like amorphous
resin is less than 40 wt %, it is difficult to solidify the
mixture. In addition, when the addition amount exceeds 90 wt %, it
is difficult to sufficiently restore the physical properties of a
deteriorated asphalt component.
EXAMPLES
[0046] Hereinafter, the present invention is described in more
detail by way of Examples and Comparative Examples, but is not
limited by the examples. It should be noted that a penetration
degree is a value determined according to JIS K2207 (1996) at
25.degree. C.
Example 1A
[0047] A waste animal or vegetable oil (obtained from a waste
disposal dealer, kinematic viscosity at 60.degree. C.: 60
mm.sup.2/s) and a waste mineral oil (obtained from a gas station,
kinematic viscosity at 60.degree. C.: 30 mm.sup.2/s) were mixed at
a ratio of 1:1 on a weight basis. It should be noted that foreign
matter was removed by passing the waste animal or vegetable oil and
the waste mineral oil through a 250-mesh woven metal strainer and a
440-mesh woven metal strainer before their use. After 9.1 parts by
weight of straight asphalt (having a penetration degree of 20 to
40) was added to 90.9 parts by weight of the mixture, the resultant
liquid was heated to 230.degree. C. while the entirety of the
liquid was stirred. The liquid was held at 230.degree. C. for 10
minutes and then left standing to cool. Thus, an additive for
reclaiming asphalt of Example 1A was obtained. Table 1 shows
various physical properties of the resultant additive for
reclaiming asphalt. Table 1 also shows various physical properties
of commercially available additives for reclaiming asphalt
(FRESHSOL 200 manufactured by SHOWA SHELL SEKIYU K.K. and T-REVIVE
manufactured by Takenaka Sangyo Co., Ltd.).
TABLE-US-00001 TABLE 1 Quality.sup.*1 Example 1A FRESHSOL 200
T-REVIVE Kinematic viscosity at 40.degree. C. 175 150.5
(mm.sup.2/s) Kinematic viscosity at 60.degree. C. 80 to 1000 80.8
526 53.39 (mm.sup.2/s) Flash point (.degree. C.) 230 or more 240
327 252 Density at 15.degree. C. (g/cm.sup.3) 0.894 0.978 0.911
Pour point (.degree. C.) 2 or less -27.5 -17.5 Viscosity ratio at
60.degree. C. after 1.05 1.1 1.08 heating of thin film Mass change
ratio after heating Within .+-.3 -1.17 -0.07 -0.82 of thin film (%)
Aromatic content.sup.*2 (wt %) 3.4 83.5 15.6 .sup.*1According to
"Pavement Recycling Handbook" (February 2004) .sup.*2The aromatic
content was measured by a TLC-FID method using an IATROSCAN.
[0048] As can be seen from the results of Table 1, the additive for
reclaiming asphalt of Example 1A satisfies all aspects of quality
as an additive for reclaiming asphalt according to a plant
recycling pavement technology guideline. In particular, since the
additive has so low a pour point, there is no need to heat the
additive at the time of its transport or storage. Further, it can
be said that the additive for reclaiming asphalt of Example 1A is
friendly to the environment and humans because its aromatic content
is extremely small as compared with that of commercially available
products. In addition, the additive for reclaiming asphalt of
Example 1A can be available at a low cost because 90 wt % or more
of the additive is formed of waste.
[0049] Next, 100 parts by weight of deteriorated asphalt (asphalt
extracted from an asphalt pavement waste, penetration degree: 27)
were heated to about 180.degree. C. 5.6 Parts by weight of the
additive for reclaiming asphalt of Example 1A were added to the
deteriorated asphalt and then the materials were mixed at about
165.degree. C. After that, the mixture was compacted at 147.degree.
C. to 152.degree. C. Thus, a reclaimed asphalt test piece was
obtained. Table 2 shows various physical properties of the
resultant reclaimed asphalt test piece.
TABLE-US-00002 TABLE 2 Example Quality.sup.*1 1A Penetration degree
(1/10 mm) More than 60 and 80 or less 73 Softening point (.degree.
C.) 44.0 to 52.0 45 Ductility at 15.degree. C. (cm) 100 or more 113
Toluene soluble matter (%) 99.0 or more 99.9 Flash point (.degree.
C.) 260 or more 317 Mass change ratio after heating 0.6 or less
-0.2 of thin film (%) Penetration degree residual ratio 55 or more
78.1 after heating of thin film (%) Penetration degree ratio after
110 or less 94.4 evaporation Density at 15.degree. C. (g/cm.sup.3)
1.000 or more 1.034 Kinematic viscosity at 120.degree. C. 1130.4
(mm.sup.2/s) Kinematic viscosity at 150.degree. C. 285.1
(mm.sup.2/s) Kinematic viscosity at 180.degree. C. 92.5
(mm.sup.2/s) .sup.*1According to "Pavement Recycling Handbook"
(February 2004)
[0050] As can be seen from the results of Table 2, the asphalt
reclaimed with the additive for reclaiming asphalt of Example 1A
satisfies all aspects of quality as reclaimed asphalt. Accordingly,
the additive for reclaiming asphalt of Example 1A can sufficiently
restore the physical properties of a deteriorated asphalt
component. Further, the asphalt reclaimed with the additive for
reclaiming asphalt of Example 1A has a kinematic viscosity at
150.degree. C. of 285 mm.sup.2/s, which means that its fluidity is
high (when a conventional additive for reclaiming asphalt is used,
the kinematic viscosity at 150.degree. C. is 350 mm.sup.2/s or
more). It is assumed from the foregoing that uniform mixing can be
performed at a lower temperature than a conventional one. In
addition, in order that the kinematic viscosity of the reclaimed
asphalt at 150.degree. C. may be adjusted with the conventional
additive for reclaiming asphalt to the same level as that of
Example 1A, the conventional additive needs to be added in an
amount about two to three times as large as that of Example 1A. A
high kinematic viscosity of the reclaimed asphalt is not desirable
because the high kinematic viscosity leads to a reduction in
strength of a reclaimed asphalt pavement material.
Example 1B
[0051] A waste animal or vegetable oil (obtained from a waste
disposal dealer, kinematic viscosity at 60.degree. C.: 60
mm.sup.2/s) and a waste mineral oil (obtained from a gas station,
kinematic viscosity at 60.degree. C.: 30 mm.sup.2/s) were mixed at
a ratio of 9:1 on a weight basis. It should be noted that foreign
matter was removed by passing the waste animal or vegetable oil and
the waste mineral oil through a 250-mesh woven metal strainer and a
440-mesh woven metal strainer before their use. After 9.1 parts by
weight of straight asphalt (having a penetration degree of 20 to
40) was added to 90.9 parts by weight of the mixture, the resultant
liquid was heated to 230.degree. C. while the entirety of the
liquid was stirred. The liquid was held at 230.degree. C. for 10
minutes and then left standing to cool. Thus, an additive for
reclaiming asphalt of Example 1B was obtained. The resultant
additive for reclaiming asphalt had a density at 15.degree. C. of
0.931 g/cm.sup.3 and a flash point of 318.degree. C.
[0052] The additive for reclaiming asphalt of Example 1B obtained
in the foregoing was added at 10 wt % with respect to the
deteriorated asphalt in an asphalt pavement waste (having a
penetration degree of 24), and then the materials were melted and
mixed at about 180.degree. C. Thus, a reclaimed asphalt pavement
material (having a penetration degree of about 70) was
obtained.
[0053] A specimen was produced by compacting the resultant
reclaimed asphalt pavement material at 165.degree. C., and was then
subjected to a wheel tracking test (vertical load: 70 kg,
60.degree. C. contact pressure: 6.4 kgf/cm.sup.2, test temperature:
60.degree. C., number of times of run: 2,520, running method: chain
type). As a result, the specimen had a dynamic stability (DS) of
5,053 times/mm (average of three measured values) and a
consolidation deformation amount of about 1.48 mm (average of three
measured values).
Comparative Example 1
[0054] A commercially available additive for reclaiming asphalt
(FRESHSOL 200 manufactured by SHOWA SHELL SEKIYU K.K.) was added at
18 wt % with respect to the deteriorated asphalt in an asphalt
pavement waste (having a penetration degree of 24), and then the
materials were melted and mixed at about 180.degree. C. Thus, a
reclaimed asphalt pavement material (having a penetration degree of
about 70) was obtained.
[0055] A specimen was produced by compacting the resultant
reclaimed asphalt pavement material at 165.degree. C., and was then
subjected to a wheel tracking test (vertical load: 70 kg,
60.degree. C. contact pressure: 6.4 kgf/cm.sup.2, test temperature:
60.degree. C., number of times of run: 2,520, running method: chain
type). As a result, the specimen had a dynamic stability (DS) of
3,088 times/mm (average of three measured values) and a
consolidation deformation amount of about 1.71 mm (average of three
measured values).
[0056] As can be seen from the results of the wheel tracking tests
of Example 1B and Comparative Example 1, it can be said that the
reclaimed asphalt pavement material using the additive for
reclaiming asphalt of Example 1B has strength and heat resistance
much higher than those of the reclaimed asphalt pavement material
using the commercially available additive for reclaiming
asphalt.
Example 2
[0057] A mixture containing 60 wt % of an asphalt pavement waste
(having a penetration degree of 27) and 40 wt % of a fresh
aggregate was heated to about 170.degree. C. 5.6 wt % of the same
additive for reclaiming asphalt as that used in Example 1A with
respect to the deteriorated asphalt in the mixture and a
predetermined amount (such an amount that the total asphalt amount
was 5.0 wt %, 5.5 wt %, 6.0 wt %, 6.5 wt %, or 7.0 wt %) of fresh
asphalt (having a penetration degree of 60 to 80) were added to the
mixture, and then the materials were mixed at about 170.degree. C.
Thus, a reclaimed asphalt pavement material was obtained.
[0058] Table 3 shows the results of the measurement of the density,
stability, flow value, percentage of voids, and degree of
saturation of the resultant reclaimed asphalt pavement material. It
should be noted that the density, the stability, the flow value,
the percentage of voids, and the degree of saturation are values
determined by a Marshall test method.
TABLE-US-00003 TABLE 3 Total Flow asphalt value Percentage Degree
of amount Density Stability (1/ of voids saturation (wt %)
(g/cm.sup.3) (kN) 100 cm) (%) (%) Example 2 5.0 2.323 13.55 30 5.3
67.9 5.5 2.327 12.69 29 4.4 73.6 6.0 2.352 12.59 35 2.7 83.7 6.5
2.357 13.45 38 1.8 89.3 7.0 2.354 12.39 41 0.9 94.5
[0059] As can be seen from the results of Table 3, the additive for
reclaiming asphalt of the present invention can produce a reclaimed
asphalt pavement material whose stability and flow value are good
even when its addition amount is as small as 5.6 wt % with respect
to the deteriorated asphalt in a mixture of an asphalt pavement
waste and a fresh aggregate. When an attempt was made to obtain a
reclaimed asphalt pavement material having the same levels of
stability and flow value with a conventional additive for
reclaiming asphalt, the conventional additive needed to be added at
10 wt % to 14 wt %.
Example 3
[0060] 1.5 Parts by weight of an expanded polystyrene were
gradually added to 1 part by weight of a mixed organic solvent
containing ethyl acetate and white kerosene at a volume ratio of
2:8. Thus, the expanded polystyrene was dissolved. Then, the
materials were mixed to provide a gel-like polystyrene. Next, the
resultant gel-like polystyrene was immersed in a mixed alcohol
containing methyl alcohol and octanol at a volume ratio of 8:2 for
about 3 hours. After that, the polystyrene was taken out and dried
at room temperature. Thus, a xerogel-like polystyrene was
obtained.
[0061] 60 Parts by weight of the xerogel-like polystyrene and 1.5
parts by weight of a waste animal or vegetable oil (obtained from a
waste disposal dealer, kinematic viscosity at 60.degree. C.: 60
mm.sup.2/s) were added to 240 parts by weight of straight asphalt
(having a penetration degree of 60 to 80) melted by being heated to
about 100.degree. C., and then the materials were mixed. Thus, a
modified asphalt of Example 3 was obtained. The resultant modified
asphalt was a uniform mixture.
Example 4
[0062] A modified asphalt was obtained in the same manner as in
Example 3 except that the amounts of the straight asphalt and the
xerogel-like polystyrene were changed to 180 parts by weight and
120 parts by weight, respectively. The resultant modified asphalt
was a substantially uniform mixture, though the modified asphalt
contained a small amount of the solidified product of the
polystyrene.
Example 5
[0063] A modified asphalt was obtained in the same manner as in
Example 3 except that the amounts of the straight asphalt and the
xerogel-like polystyrene were changed to 120 parts by weight and
180 parts by weight, respectively. The resultant modified asphalt
was a substantially uniform mixture, though the modified asphalt
contained a small amount of the solidified product of the
polystyrene.
Example 6
[0064] A modified asphalt was obtained in the same manner as in
Example 3 except that the amount of the waste animal or vegetable
oil was changed to 9 parts by weight. The resultant modified
asphalt was a uniform mixture.
Example 7
[0065] A modified asphalt was obtained in the same manner as in
Example 3 except that the amounts of the straight asphalt, the
xerogel-like polystyrene, and the waste animal or vegetable oil
were changed to 180 parts by weight, 120 parts by weight, and 9
parts by weight, respectively. The resultant modified asphalt was a
uniform mixture.
Example 8
[0066] A modified asphalt was obtained in the same manner as in
Example 3 except that the amounts of the straight asphalt, the
xerogel-like polystyrene, and the waste animal or vegetable oil
were changed to 120 parts by weight, 180 parts by weight, and 9
parts by weight, respectively. The resultant modified asphalt was a
substantially uniform mixture, though the modified asphalt
contained a small amount of the solidified product of the
polystyrene.
Example 9
[0067] A modified asphalt was obtained in the same manner as in
Example 3 except that the amount of the waste animal or vegetable
oil was changed to 27 parts by weight. The resultant modified
asphalt was a uniform mixture.
Example 10
[0068] A modified asphalt was obtained in the same manner as in
Example 3 except that the amounts of the straight asphalt, the
xerogel-like polystyrene, and the waste animal or vegetable oil
were changed to 180 parts by weight, 120 parts by weight, and 27
parts by weight, respectively. The resultant modified asphalt was a
uniform mixture.
Example 11
[0069] A modified asphalt was obtained in the same manner as in
Example 3 except that the amounts of the straight asphalt, the
xerogel-like polystyrene, and the waste animal or vegetable oil
were changed to 120 parts by weight, 180 parts by weight, and 27
parts by weight, respectively. The resultant modified asphalt was a
uniform mixture.
Comparative Example 2
[0070] The same operations as those of Example 3 were performed
except that the waste animal or vegetable oil was not added. As a
result, the added xerogel-like polystyrene solidified and hence a
uniform mixture could not be obtained.
Comparative Example 3
[0071] The same operations as those of Example 3 were performed
except that 1.5 parts by weight of a REDICOTE E-11 (asphalt
emulsifier) manufactured by Lion Corporation were added instead of
1.5 parts by weight of the waste animal or vegetable oil. As a
result, the added xerogel-like polystyrene solidified and hence a
uniform mixture could not be obtained.
Comparative Example 4
[0072] The same operations as those of Example 3 were performed
except that 1.5 parts by weight of DUOMEEN T (asphalt emulsifier)
manufactured by Lion Corporation were added instead of 1.5 parts by
weight of the waste animal or vegetable oil. As a result, the added
xerogel-like polystyrene solidified and hence a uniform mixture
could not be obtained.
Comparative Example 5
[0073] A modified asphalt was obtained in the same manner as in
Example 3 except that 1.5 parts by weight of Newcol 1203 (nonionic
surfactant) manufactured by Nippon Nyukazai Co., Ltd. were added
instead of 1.5 parts by weight of the waste animal or vegetable
oil. The resultant modified asphalt was a substantially uniform
mixture, though the modified asphalt contained a small amount of
the solidified product of the polystyrene.
[0074] As can be seen from the results of Comparative Examples 3
and 4, the xerogel-like polystyrene could not be dispersed in the
straight asphalt with a commercially available asphalt emulsifier.
Further, as can be seen from the results of Examples 3 to 11, and
Comparative Example 2 and Comparative Example 5, the waste animal
or vegetable oil is assumed to serve to disperse the xerogel-like
polystyrene in the straight asphalt. Although Newcol 1203
manufactured by Nippon Nyukazai Co., Ltd. can disperse the
xerogel-like polystyrene in the straight asphalt, Newcol 1203 is
more expensive than the waste animal or vegetable oil and hence
cannot be put into practical use. In addition, even when the types
of amorphous resin was changed to an ABS resin or a polyvinyl
chloride, the same tendency as that of the polystyrene was
observed.
Example 12
[0075] 1.5 Parts by weight of an expanded polystyrene were
gradually added to 1 part by weight of a mixed organic solvent
containing ethyl acetate and white kerosene at a volume ratio of
2:8, thus dissolving the expanded polystyrene. Then, the materials
were mixed to provide a gel-like polystyrene.
[0076] 750 Parts by weight of the gel-like polystyrene and 30 parts
by weight of a waste animal or vegetable oil (obtained from a waste
disposal dealer, kinematic viscosity at 60.degree. C.: 60
mm.sup.2/s) were added to 250 parts by weight of straight asphalt
(having a penetration degree of 60 to 80) melted by being heated to
about 100.degree. C., and then the materials were mixed. Thus, the
modified asphalt of Example 12 was obtained. The resultant modified
asphalt was a uniform mixture.
Example 13
[0077] A modified asphalt was obtained in the same manner as in
Example 12 except that the amounts of the straight asphalt and the
gel-like polystyrene were changed to 200 parts by weight and 800
parts by weight, respectively. The resultant modified asphalt was a
uniform mixture.
Example 14
[0078] A modified asphalt was obtained in the same manner as in
Example 12 except that the amounts of the straight asphalt and the
gel-like polystyrene were changed to 100 parts by weight and 900
parts by weight, respectively. The resultant modified asphalt was a
uniform mixture.
Comparative Example 6
[0079] The same operations as those of Example 12 were performed
except that the waste animal or vegetable oil was not added. As a
result, the added gel-like polystyrene solidified and hence a
uniform mixture could not be obtained.
Comparative Example 7
[0080] The same operations as those of Example 12 were performed
except that the amounts of the straight asphalt and the gel-like
polystyrene were changed to 500 parts by weight and 500 parts by
weight, respectively. As a result, the added gel-like polystyrene
solidified and hence a uniform mixture could not be obtained.
[0081] As can be seen from the results of Examples 12 to 14 and
Comparative Example 6, the addition of 70 wt % or more of the
gel-like polystyrene enabled uniform dispersion of the gel-like
polystyrene in the straight asphalt. Further, the adhesion of a
large amount of the straight asphalt to a mixer was observed in
Comparative Example 6 while the straight asphalt in each of the
modified asphalts of Examples 12 to 14 did not cling to a mixer. On
the other hand, as can be seen from the result of Comparative
Example 7, when the addition amount of the gel-like polystyrene was
less than 70 wt %, the gel-like polystyrene could not be dispersed
in the straight asphalt. This is assumed to be because the mixed
organic solvent in the gel-like polystyrene exerts a certain
influence.
Example 15
[0082] The modified asphalt obtained in Example 13 was added at 2
wt % with respect to the deteriorated asphalt in an asphalt
pavement waste (having a penetration degree of 27), and then the
materials were melted and mixed at about 160.degree. C., thus to
obtain a reclaimed asphalt pavement material.
[0083] A specimen was produced by compacting the resultant
reclaimed asphalt pavement material at 150.degree. C., and this was
then subjected to a wheel tracking test (vertical load: 70 kg,
60.degree. C. contact pressure: 6.4 kgf/cm.sup.2, test temperature:
70.degree. C., number of times of run: 2,520, running method: chain
type). As a result, the specimen had a dynamic stability (DS) of
15,750 times/mm and a rut depth of about 0.5 mm. FIG. 1 shows the
surface state of the reclaimed asphalt pavement material after the
wheel tracking test.
Comparative Example 8
[0084] A specimen was produced from a commercially available
dense-graded asphalt mixture (modified type II) and then subjected
to the wheel tracking test under the same conditions. As a result,
the specimen had a dynamic stability (DS) of 880 times/mm and a rut
depth of about 25 mm. In addition, the wheel tracking test was
performed while the test temperature was changed to 60.degree. C.
As a result, the specimen had a dynamic stability (DS) of 4,366
times/mm and a rut depth of about 5 mm. FIG. 2 shows the surface
state of the asphalt pavement material after the wheel tracking
test.
Comparative Example 9
[0085] A specimen was produced from a commercially available blown
asphalt mixture and then subjected to the wheel tracking test under
the same conditions. As a result, the specimen had a dynamic
stability (DS) of 8,289 times/mm and a rut depth of about 1 mm.
FIG. 3 shows the surface state of the asphalt pavement material
after the wheel tracking test.
[0086] As can be seen from the results of Comparative Example 8, an
asphalt pavement material obtained from a dense-graded asphalt
mixture that is now on the market had a dynamic stability (DS) of
4,366 times/mm at a test temperature of 60.degree. C. but the
dynamic stability was reduced by a factor of about 5 at a test
temperature of 70.degree. C. It can be said from the foregoing that
ruts will immediately appear in the asphalt pavement material as
global warming progresses in the future, and road surface
temperatures exceed 60.degree. C. In contrast, it can be said that
there is no fear of ruts appearing in the reclaimed asphalt
pavement material of Example 15 because the material has much
higher heat resistance than that of the asphalt pavement material
(Comparative Example 9) obtained from the blown asphalt mixture
that has heretofore been considered as having high heat resistance.
In other words, it can be said that a reclaimed asphalt pavement
material obtained by adding the modified asphalt of the present
invention to an asphalt pavement waste is an extremely useful
alternative to the asphalt pavement material obtained from a blown
asphalt mixture. In addition, the melt-mixing temperature and
compaction temperature of a blown asphalt mixture needed to be set
to about 190.degree. C. and about 180.degree. C., respectively, but
the production of the pavement material in Example 15 was attained
at temperatures about 30.degree. C. lower than those temperatures.
Further, the reclaimed asphalt pavement material of Example 15 was
found to have high heat-retaining properties because the time
period during which the material could be compacted after the
melting and mixing was 2 hours or more.
[0087] Next, in order to investigate the mechanism via which the
heat resistance of the reclaimed asphalt pavement material obtained
in Example 15 improved, a specimen similar to that produced in
Example 15 was produced and then heated to 70.degree. C. to
80.degree. C. After that, the specimen was bent and its fracture
cross-section was then observed. FIG. 4 is a photograph of the
fracture cross-section. As can be seen from FIG. 4, a state where a
thin thread-like resin was intertwined with the entirety of the
aggregate was observed.
* * * * *