JPH0873750A - Additive for recycled hot asphalt mixture, recycled hot asphalt mixture using same, and production of same - Google Patents

Abstract

PURPOSE: To realize the excellent preventive effect against separation between asphalt and an aggregate and recycle waste asphalt-concrete pavement materials by using a specific acidic org. phosphoric acid compd. as an additive for a recycled hot asphalt mixture. CONSTITUTION: The additive comprises acidic org. phosphoric acid compds. of the formula (R is an 8-36C satd. or unsatd. aliph. hydrocarbon group or an 8-26C alkylphenyl group; m is 1 or 2; n is an integer of 0-10; and k is 1 or 2 provided m+k is 3), pref. comprising 40-95mol% 16-12C linear or branched satd. or unsatd. aliph. monophosphoric ester and 60-5mol% 16-18C linear or branched satd. or unsatd. aliph. diphosphoric ester. The additive in an amt. of about 0.05-5 pts.wt. is added to 100 pts.wt. recycled asphalt.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to improving the quality of a recycled heated asphalt mixture used for road paving or the like. More specifically, the present invention relates to an additive for a regenerated heated asphalt mixture consisting of a specific acidic organic phosphoric acid compound, a regenerated asphalt mixture using the same, and a method for producing the same, more specifically, a bituminous substance and bone. Reinforcement of regenerated heated asphalt mixture, which makes it possible to develop an extremely excellent anti-stripping effect on bituminous material by strengthening the adhesion with the material, a regenerated asphalt mixture using the same, and a method for producing the same It is a thing.

[0002]

BACKGROUND OF THE INVENTION Regarding the reuse of asphalt concrete pavement waste materials, there is a growing nationwide tendency to meet the needs of the times of effective use of resources, waste control and environmental problems. Going on,
In 1991, "Act on Promotion of Utilization of Recycled Resources"
(Recycling Law) has been enforced, and there is an urgent need to use it efficiently.

By the way, the asphalt in the asphalt mixture, which is an aged pavement waste material, is a marten fraction (which is composed of a polar fraction soluble in n-pentane, an aromatic fraction and a saturated fraction) in the asphalt. Is oxidized or polymerized to be transferred to asphaltene (which means n-pentane insoluble matter), so that the maltene fraction is relatively insufficient in chemical composition as compared with the original asphalt. As a result, the physical properties of the asphalt mixture will deteriorate and the stress relaxation performance will decrease. Therefore, by adding a rejuvenating additive having a physical property close to that of a marten distillate or a new asphalt for replenishment to the asphalt mixture, the physical properties of the original raw asphalt are approximated to the recovery and regeneration.

However, looking at the usage situation so far,
As a general trend, regenerated mixtures are more prone to fatigue failure than new mixtures, thus leading to early cracking in some cases. Even if a rejuvenating additive is added to bring the physical properties of the asphalt closer to those of the original asphalt, since the amount of asphaltene is still higher than that of the original asphalt, the adhesiveness between the aggregate and the asphalt is higher than that of the original asphalt. However, it is thought that this is because it decreases.

As a means for imparting sufficient fatigue resistance to such a regenerated mixture, a regenerated heated asphalt mixture prepared by blending a fine aggregate into a regenerated aggregate mixture is known.
Although it is devised in Japanese Patent Laid-Open No. 5-112724, it is not mentioned about the improvement of the adhesion between the asphalt having a large amount of asphaltene component and the aggregate.

Japanese Patent Publication No. 54-23691 discloses that asphalt aggregates are prepared by adding phosphorus compounds such as phosphorus pentoxide, polyphosphoric acid and phosphorus pentasulfide with stirring to molten asphalt containing a specific asphaltene. Although improvement of adhesion has been devised, there is practically no means of addition for addition to the regenerated heated asphalt mixture, and since these phosphate compounds are inorganic substances, the state of dispersion in organic substances is not always good. No, the adhesion performance of asphalt to aggregate is insufficient.

JP-A-60-188462 describes that an acidic organic phosphoric acid compound has a peeling-preventing effect, but it is added to a regenerative heating asphalt mixture and a regenerative heating in which an additive for regeneration is added. No mention is made of addition to the asphalt mixture.

[0008]

DISCLOSURE OF THE INVENTION The inventors of the present invention have made diligent efforts with respect to the effect of preventing the peeling of the regenerated heated asphalt mixture from the asphalt and the aggregate, and as a result, a certain acidic organic phosphoric acid compound has a particularly excellent peeling prevention effect. They have found that they have the ability to exert effects, and have completed the present invention.

That is, the present invention relates to an additive for regenerated heated asphalt mixture comprising an acidic organic phosphoric acid compound represented by the following general formula (a).

[0010]

Embedded image

(Wherein R represents a saturated or unsaturated aliphatic hydrocarbon group having 8 to 36 carbon atoms or an alkylphenyl group having 8 to 26 carbon atoms, m is an integer of 1 or 2, and n is 0 to 0). An integer of 10, k is an integer of 1 or 2, and m + k is 3.) The present invention is characterized in that 0.05 to 5 parts by weight of the above additive is added to 100 parts by weight of recycled asphalt. Regeneration heated asphalt mixture.

Further, the present invention is characterized in that the above-mentioned additive is previously added to the regenerating additive and / or the replenishing new asphalt, and then the asphalt mixture is kneaded. Regarding the method.

The additive of the present invention may be a single compound or a mixture of a plurality of compounds.

Conventionally devised higher aliphatic polyamines and their derivatives are adsorbed and oriented in polar positive and negative polar groups,
Improves wetting between bituminous material and aggregate. However, it is effective for initial adhesion, but has a problem for long-term adhesion. For example, when external stress such as temperature rise and dynamic load is applied in the presence of water for a long period of time, since the additive itself is a surfactant, it acts as a bituminous emulsifier and removes bitumen from the aggregate. There is a drawback that

The present invention has a composition in which molecules are arranged most densely at the interface between the bituminous material and the aggregate, and further, as shown in the following reaction formula, a chemical bond is formed at the interface by a dehydration reaction to strengthen the structure. To adhere and polymerize with acidic organic phosphoric acid compound itself and inorganic phosphoric acid compound to form a strong hydrophobic film on the aggregate surface, so that even if water enters the aggregate surface, replace it with bituminous substance It is considered that it exhibits an excellent effect of preventing peeling, in which the adhesive interface between the aggregate and the bituminous material is not broken even when subjected to an impact.

[0016]

[Chemical 3]

Here, it is essential that the acidic organic phosphoric acid compound used in the present invention has a P—OH group in the molecule and is represented by the following general formula (a).

[0018]

[Chemical 4]

(In the formula, R represents a saturated or unsaturated aliphatic hydrocarbon group having 8 to 36 carbon atoms or an alkylphenyl group having 8 to 26 carbon atoms, m is an integer of 1 or 2, and n is 0 to The integer of 10, k is an integer of 1 or 2, and m + k is 3.) The acidic organic phosphoric acid compound used in the present invention can be industrially and easily produced by a generally known method. (P ₂ O ₃ ), phosphorus oxytrichloride (POCl ₃ ), phosphorus trichloride (PC
l ₃ ) or a phosphorylating agent such as polyphosphoric acid and the formula RO (C ₂ H ₄ O) _n H
It is produced by a reaction with a hydroxyl compound represented by

The organic group represented by R is preferably an aliphatic hydrocarbon group having 8 to 36 carbon atoms or 8 carbon atoms.
To 26 alkylphenyl groups, which may be saturated or unsaturated, straight-chain or branched.

Examples of such aliphatic hydrocarbon groups include octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, eicosyl, heneicosyl, docosyl, tricosyl, tetracosyl. , Triacontyl, pentatriacontyl, hexatriacontyl, and the like, and examples of the alkylphenyl group include ethylphenyl, propylphenyl, butylphenyl, pentylphenyl, hexylphenyl,
Heptylphenyl, octylphenyl, nonylphenyl, decylphenyl, undecylphenyl, dodecylphenyl, tridecylphenyl, tetradecylphenyl,
Examples include pentadecylphenyl, hexadecylphenyl, heptadecylphenyl, octadecylphenyl, nonadecylphenyl, eicosylphenyl.

The organic group is bonded to another atomic group directly or via an oxyalkylene bond to form an acidic organic phosphoric acid compound. The alkylene of this oxyalkylene is ethylene, propylene, butylene, pentylene,
There are hexylene, heptylene, octylene, nonylene, and decene. Among them, ethylene is industrially the cheapest and most preferable.

Typical examples of the raw material hydroxyl compound generally used for obtaining the compound represented by the above general formula (a) include the following. 2-ethylhexyl alcohol, decyl alcohol, lauryl alcohol, myristyl alcohol, palmityl alcohol, stearyl alcohol, isostearyl alcohol, oleyl alcohol, arachidyl alcohol and other aliphatic alcohols, octylphenol,
Alkylphenols such as nonylphenol, synthetic alcohols by oxo method, Ziegler method and Garpet method, or alcohols obtained by adding 1 to 10 mol of alkylene oxide, preferably ethylene oxide,
And most higher alcohols such as their respective mixtures.

Here, in order to form an optimal adhesive interface that is dense in terms of molecular structure and arrangement, a straight chain or branched chain saturated or unsaturated aliphatic phosphate ester having 16 to 18 carbon atoms is most preferable.

Furthermore, in order to form an optimal adhesive interface which is dense in terms of molecular structure and arrangement, a linear or branched saturated or unsaturated aliphatic monophosphate ester (A) having 16 to 18 carbon atoms is used. A linear or branched saturated or unsaturated aliphatic diphosphate ester having 16 to 18 carbon atoms (B), and A /
It is important that the composition ratio of (A + B) × 100 (mol%) is 40 to 95, and even if the monophosphate ratio is less than 40,
Even if it exceeds 95, it is difficult to obtain such a dense molecular arrangement and chemical bond, and the peeling prevention performance is insufficient. More preferably, A / (A + B) × 100 (mol%) is 60 to
90.

The values of A and B used here can be obtained by the following analysis method for acidic organic phosphoric acid compounds (for example, the method described in JP-B-58-8746). That is, 1 g of the product was subjected to potentiometric titration with an alkali by a conventional method to obtain the amount of alkali (amg) required up to the first equivalence point and the amount of alkali (bmg) required up to the second equivalence point. After adding the acidic phosphate OH groups present in and the silver nitrate in a chemical equivalent or more, potentiometric titration with alkali was performed in the same manner to obtain the alkali amount (cmg) required up to the 3rd equivalence point. Calculate the content.

[0027]

[Equation 1]

An acidic organic phosphoric acid compound having a predetermined ester composition ratio can be obtained depending on the type of phosphorylating agent used, the molar ratio of the hydroxyl compound to the phosphorylating agent, addition of water, and the like.

The additives of the present invention are 100% recycled asphalt.
0.05 to 5.0% by weight, preferably 0.1 to 3.0% by weight
% By weight. If it is less than 0.05% by weight, the effect will be reduced to 5.0.
Although it is effective if the content exceeds 10% by weight, it is not economical.

Here, recycled asphalt will be defined. Recycled asphalt is a mixture of recovered asphalt recovered from waste pavement material, a rejuvenating additive and / or a new replenishing asphalt, with a supplemental agent added if necessary.

FIG. 1 shows a flow from recovery of asphalt mixture pavement waste from the site to regenerated heated asphalt mixture. Further, FIG. 2 shows a flow of a blending design of the regenerated heated asphalt mixture.

That is, according to the required quality of recycled asphalt, the compounding ratio of new asphalt for replenishment, additive for regeneration, supplementary material, etc., so as to meet the target penetration (design penetration). To decide. To adjust the design penetration, use a rejuvenating additive or new asphalt.

Generally, the recovered asphalt in aged pavement waste materials often has a penetration of less than 30 because the marten fraction in the asphalt has been converted to asphaltene. Design penetration of recycled asphalt adjusted by new asphalt is 50-80
Is.

From the above, the amount of recycled asphalt defined in the present invention is the total amount of the recovered asphalt and the replenishing new asphalt and / or the additive for regeneration.

Further, the reclaiming additive defined in the present invention means a plant reclaiming paving technical guideline (published by Japan Road Association).
It complies with the quality of the rejuvenating additive shown in
There is no particular limitation, and the penetration of deteriorated old asphalt is restored to the same level as that of new asphalt.

Therefore, the present invention does not have the function of preventing the separation between the asphalt and the aggregate which is the object of the present invention.

The regenerated crushed stone used in the present invention refers to the regenerated material described in the above-mentioned technical guidelines, and the generation source and processing method are not particularly limited.

New asphalt for replenishment used in the production of recycled heated asphalt mixture is straight asphalt, semi-prone asphalt, modified asphalt I.
Type and modified asphalt type II are used, but straight asphalt is generally used.

The regenerated heated asphalt mixture of the present invention is prepared by adding the additive of the present invention to the rejuvenating additive and / or replenishing new asphalt preheated in the range of 120 to 200 ° C. and thoroughly mixing the regenerated crushed stone. It is characterized by being manufactured by kneading with new crushed stone. In the production of the recycled heated asphalt mixture of the present invention, the additive of the present invention is uniformly dispersed in the recycled asphalt by adding the additive of the present invention to the preheated additive for regeneration and / or new asphalt for supplementation. However, a homogeneous regenerated heated asphalt mixture is obtained. If the additive of the present invention is mixed in advance with regenerated crushed stone or new crushed stone, it may be localized and a homogeneous asphalt mixture may not be obtained, which is not preferable.

In order to achieve the object of the present invention better, various aliphatic amines may be used in combination with the acidic organic phosphoric acid compound of the present invention. This means that the initial wetting is further enhanced by having a nitrogen atom in the molecule. The amines are not particularly limited, but as general ones, higher aliphatic polyamines such as beef tallow propylenediamine and derivatives thereof, alkylhydroxyamines, monoethanolamine, diethanolamine, triethanolamine and other alkylolamines, etc. However, it is preferably used on the neutral or acidic side. The various aliphatic amines used in combination with the acidic organic phosphoric acid compound of the present invention are not limited to these.

In addition to thermoplastic resins and rubber substances, for example, inorganic and organic fillers such as calcium carbonate, slaked lime, Portland cement and activated carbon, petroleum softeners such as petroleum resin and low molecular weight polyethylene, and oleic acid. It is also possible to use it in a combination system of the vegetable oil-based softening agent, various plasticizers, sulfur and the like with the acidic organic phosphate compound of the present invention.

[0042]

EXAMPLES The present invention will be specifically described below, but the present invention is not limited to these examples.

In order to confirm the effect of the present invention, a water immersion Marshall test was carried out, and the peeling condition after splitting the test specimen was visually observed to evaluate the asphalt peeling rate in area%.

The water immersion Marshall test was in accordance with the test method KODAN 202 “Marshall Test Method for Asphalt Mixtures” of the Japan Highway Public Corporation. However, the water immersion time of the test piece was increased from 48 hours to 96 hours, and the test was performed under more severe conditions.
The test was conducted according to the Marshall stability test method (asphalt pavement guideline). The type of asphalt mixture used in this test was a dense particle size asphalt mixture (13 mm), and the design penetration of the recycled asphalt was adjusted to 50. The test reclaimed asphalt mixture specimen is prepared by heating and dissolving reclaiming additive and / or replenishing new asphalt at 165 to 180 ℃,
After preparing the mixture by adding the additive of the present invention according to the conditions,
It was made by kneading recycled crushed stone and new crushed stone heated to 165-180 ℃. Mixing conditions are mixing temperature 1
The temperature was 65 to 180 ° C and the compaction temperature was 165 to 180 ° C. Ten test pieces (10 cm in diameter, approximately 6.3 cm thick cylindrical) were made,
Of these, 5 have undergone the standard Marshall test and the remaining 5 have
The sample was immersed in a constant temperature water bath at 60 ° C. for 96 hours, and after completion of the immersion, the Marshall stability of the specimen was determined. Residual stability by the water immersion Marshall test was calculated from the following formula.

[0045]

[Equation 2]

The mixing ratio of the recycled crushed stones (R-2, R-3) and the new crushed stone (sandstone) (No. 6) used was R-2: R-
It was used in No. 3: 6 = 5: 4: 1. Table 1 shows the physical properties of the regenerated crushed stone.

[0047]

[Table 1]

Example 1 To a mixture of R-2, R-3 and No. 6 crushed stones, a rejuvenating additive was added so that the penetration of regenerated asphalt was 50, and 0.5% by weight based on the regenerated asphalt. % Stearyl alcohol phosphate ester (A / (A + B)
X100 = 60 mol%) was added to the additive for regeneration, and then a sample was prepared. Immersion Marshall test residual stability is 93.5
%, The asphalt peeling rate was 0%.

Comparative Example 1 The same procedure as in Example 1 was carried out except that the phosphoric acid ester of stearyl alcohol was not used. The residual stability of the water immersion Marshall test was 35.1%, and the asphalt peeling rate was 45%.

Examples 2 to 15 and Comparative Examples 2 to 5 Tests were conducted in the same manner as in Example 1 except that shown in Table 2.
Table 2 shows the results.

[0051]

[Table 2]

Reference Example 1 Reference Example 1 is shown below in order to clarify the quality difference between the regenerated heated asphalt mixture and the new heated asphalt mixture. A dense-grained asphalt mixture (13 mm) specimen was prepared using new crushed stone and new asphalt (penetration: 50). The residual stability of the water immersion Marshall test was 49.5% and the asphalt peeling rate was 30%. It can be seen that the quality of the regenerated heated asphalt mixture is lower than that of the new heated asphalt mixture.

Reference Example 2 Reference Example 2 is shown below in order to clarify the peeling prevention effect of the product of the present invention for the regenerated heated asphalt mixture and the new heated asphalt mixture. New crushed stone, new asphalt (penetration: 50), phosphoric acid ester of stearyl alcohol (A / (A + B) x 100 = 60 mol%) (0.5% by weight based on the new asphalt is added to the new asphalt in advance and uniformly Denser asphalt mixture (1)
3 mm) Specimens were prepared. The residual stability of the water immersion Marshall test was 93.5%, and the asphalt peeling rate was 0%.

[0054]

According to the examples, the regenerated asphalt using the additive for regenerated heated asphalt mixture of the present invention has improved adhesiveness with aggregates and remarkably improved peeling prevention effect,
It is clear that the durability is improved. Further, according to the reference example, the regenerated heated asphalt mixture to which the product of the present invention is not added has a lower quality than the new heated asphalt mixture, but by using the product of the present invention, the new product of the present invention is added. It has the same quality as the hot asphalt mixture. Therefore, this additive promotes the recent reuse of asphalt concrete pavement waste materials, and is expected to have great merits in terms of effective use of resources, suppression of waste, and response to environmental problems. Is big.

[Brief description of drawings]

FIG. 1 is a flow diagram from recovery of asphalt mixture pavement waste from the site to recycled heated asphalt mixture.

FIG. 2 is a mixture design flow chart of a regenerated heated asphalt mixture.

Claims (5)

[Claims] 1. An additive for a regenerated heated asphalt mixture, which comprises an acidic organic phosphoric acid compound represented by the following general formula (a). Embedded image (In the formula, R represents a saturated or unsaturated aliphatic hydrocarbon group having 8 to 36 carbon atoms or an alkylphenyl group having 8 to 26 carbon atoms, m is an integer of 1 or 2, and n is an integer of 0 to 10. , K is 1
Alternatively, it represents an integer of 2, and m + k is 3. ) 2. The acidic organic phosphoric acid compound has 16 to 18 carbon atoms.
Of a linear or branched saturated or unsaturated aliphatic monophosphate ester (A) and a linear or branched saturated or unsaturated aliphatic diphosphate ester of 16 to 18 carbon atoms (B), The additive for regenerated heated asphalt mixture according to claim 1, wherein A / (A + B) × 100 (mol%) is 40 to 95. 3. The method according to claim 1, wherein 100 parts by weight of recycled asphalt is used.
Alternatively, 0.05 to 5 parts by weight of the additive described in 2 is added to the regenerated heated asphalt mixture. 4. The reclaimed asphalt is a mixture of reclaimed crushed stone obtained by crushing or crushing waste asphalt pavement material, crushed new material, and rejuvenating additive and / or replenishing new asphalt. Regeneration heated asphalt mixture. 5. The regeneration heating according to claim 4, wherein the additive according to claim 1 or 2 is added in advance to the additive for regeneration and / or the new asphalt for supplementation, and then the asphalt mixture is kneaded. Method for producing asphalt mixture.