JPS60260455A - Manufacture of pavement asphalt concrete and additive for reinforcing asphalt concrete - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing thermally engineered asphalt concrete using a thermoplastic resin as a reinforcing material and to an addition H for reinforcing asphalt trunk concrete.

Thermal engineered asphalt concrete 1.
It is obtained by mixing it with straight asphalt (mainly straight asphalt), and is widely used as a road paving material because of its excellent cost and performance. Its static strength is expressed by Marshall stability, and the higher the value, the better it can withstand heavy traffic. In the case of dense-grained asphalt concrete, which is currently most commonly used for the surface layer, the amount of asphalt is 6 to 6.5% (by weight).
, below), the Marshall stability is highest,
It usually shows a value of 700 to 850 kg. By the way, the standard value is 750 or higher for C traffic or higher, and 500 or higher for other traffic. In addition, the base layer usually has asphalt a of 4.5
~6% coarse-grained asphalt] Concrete and upper roadbed should contain 3.5 to 4% asphalt as a stabilizer.The stability is said to be 500 or more for the base layer and 350 or more for the upper layer roadbed. There is.

On the other hand, the proportion of asphalt in the material cost of asphalt concrete is extremely high, reaching 50% in the case of standard dense-grained asphalt concrete, and this proportion and overall cost are increasing as crude oil prices rise. be. However, when the amount of asphalt is reduced, the stability decreases. For example, in the case of a dense grain size, if the asphalt content is 4%, the stability becomes around 550, making it unusable.

In view of the above, the present inventors conducted various studies and succeeded in reducing the proportion of asphalt without reducing stability by using strips of polyvinyl chloride film (
Patent application No. 57-225293). That is, when mixing aggregate and bituminous material, strips of polyvinyl chloride film are mixed with asphalt at a ratio of 0.5 to 5%, and when an inorganic polymerization initiator is added, each time a surfactant is added, asphalt Even when the ratio of 3.5% to 5% (in the case of dense-grained asphalt concrete), asphalt concrete with a stability of 750 or higher and in some cases as high as 1,300 could be obtained.

When the asphalt i is around 4%, the stability is highest, and when the asphalt i is around 6%, there is almost no increase in stability.

This fact suggests that fragments of polyvinyl chloride film that have been melted and partially decomposed in asphalt are repolymerized by the action of an inorganic polymerization initiator, resulting in the formation of aggregates or aggregates and asphalt. III is measured.

In addition, the present inventors similarly reduced the amount of asphalt to about 4% and added putty-like polystyrene (styrofoam melted and softened by 1/8 inch) and putty-like polystyrene and polyvinyl chloride film pieces. Succeeded in obtaining something with amazing stability.
8-89595).

Based on the above facts, the inventor continued to conduct further experiments, and as a result, found that thin pieces of polyvinyl chloride film or thermoplastic resins other than putty-like polystyrene had a similar reinforcing effect, and thus completed the present invention. The present invention will be described in detail below.

In the present invention, Borier senshin and polypropylene are used.

Molded products such as polystyrene, pulverized products thereof, virgin resins such as polyethylene, polypropylene, polystyrene, polyvinyl chloride, copolymers thereof, emulsions, or mixtures thereof are preferably used. Also used is a putty-like polystyrene obtained by melting and softening expanded polystyrene with a solvent, defoaming it, and drying and pulverizing it. In this case, as the solvent, thinner, acetone, ligroin, styrene monomer, a mixture of ethyl alcohol and trichlene, etc. are used.

By the way, most unnecessary resin molded products (so-called waste plastics) are currently disposed of by incineration or landfill, but the former has problems such as generation of toxic gas and damage to incinerators, and the latter has limited space and is a big waste. This is a four-part problem. In some cases, resins are thermally decomposed to extract the active ingredients or melted and remolded, but this requires pretreatment such as sorting and cleaning, and is not cost-effective. do not have. On the other hand, in the present invention, even if various resins are mixed together, or even if there is dirt attached, such as agricultural waste film, it can be used by pulverizing it as it is. Moreover, 80 to 90% of waste plastics are thermoplastic resins, and up to 90% of them are the resins mentioned above, so it is a great advantage to be able to utilize them effectively.

However, these thermoplastic resins are thermally decomposed by heated asphalt or heated aggregate in a mixer (the temperature of heated asphalt is usually 160 to 1'70°C, but quality problems may occur up to about 240°C). ), dispersed in asphalt. When a polymerization initiator is added in this state, repolymerization begins, and as the temperature of the mixture decreases, the resin begins to solidify, and after paving, the compacted aggregates or aggregates and asphalt are fused together. incorporated in the state.

'As a result, the stability of asphalt concrete increases,
It is thought that even if the amount of asphalt is less than the standard amount, it will provide the same or higher strength than the standard amount. In addition, it may be necessary to mix separately thermally decomposed materials into asphalt or mixers, or to use materials that have been partially or completely decomposed by means other than heat, such as chemicals such as solvents, acids, alkalis, light, radiation, etc. It's okay. In this way, a resin with a high heat resistance temperature can also be used. The mixing ratio of the resin is preferably 0.5 to 5%, particularly 1 to 3% for asphalt resistance, from the viewpoint of improving stability.

On the other hand, the polymerization initiator is preferably an inorganic one from the viewpoint of heat resistance, and peroxo acid salts and aqueous hydrogen peroxide are particularly effectively used. Beroxo salts include peroxonitric acid, beloxocarbonate, belooxonisulfate, peroxoboric acid, and peroxosulfate.

Ammonium salts and potassium salts such as peroxophosphoric acid.

There are sodium salts, etc. These have properties as oxidizing agents, and among these, potassium salts and ammonium salts of peroxonisulfate are known as polymerization initiators, but peroxoborates also exhibit extremely excellent effects in the present invention. These are used in an amount of about 0.1 to 1% based on the amount of asphalt, but more preferably 0.2 to 0.5%. Nine-dimensional hydrogen peroxide is also an oxidizing agent, but like the beroxo acid salt, polymerization The stability can be increased depending on the type and mixing ratio of the resin that acts as an initiator. However, if the amount of hydrogen peroxide is too small, the polymerization effect will not be sufficient, and if it is too large, the stability will decrease, probably because it decomposes the asphalt.
With a concentration of 30%, 0.1 to 1%, more preferably 0.2 to 0.5% of asphalt is used. However, when hydrogen peroxide is added, the asphalt expands in volume due to foaming, which is thought to be one of the reasons why the asphalt covers the aggregate well and later increases its stability.

In addition, when a surfactant is added to these reaction systems, stability is often improved (in the case of beroxo acid salts), but this is because the resin and polymerization initiator are more uniformly dispersed in the asphalt. This seems to be because the reaction is more complete. This surfactant may be cationic or anionic, but nonionic surfactants are particularly preferred. This seems to be due to the fact that the aggregate is positively charged and the asphalt is negatively charged. The ratio of surfactant to asphalt is 0.3 to 4%, especially 0.5%.
~2% is preferred.

By the way, the most preferable ratio of asphalt in normal surface asphalt concrete is 6 to 6.5% as mentioned above (the smaller the amount of fine aggregate or filler is, the larger it is); In the case of the invention, the most preferable ratio is smaller than this value, and this is also a major feature. That is, the preferable ratio of asphalt in the present invention is about 3 to 6%, especially about 3.5 to 5% in the case of dense-grained asphalt concrete.

This is because if it is around 6%, the thermoplastic resin will not be able to exert sufficient reinforcing action because the amount of asphalt 1 that covers the surface of the aggregate will be insufficient, and if it is too cal, the binder action will be insufficient and it will become brittle. Moreover, stability deteriorates. In the case of 4 to 5%, of course the conventional product of 6%, depending on the type of resin and the combination of polymerization initiators, the stability is equivalent to that of conventional products using reinforcing additives such as rubber-based additives. You can get the following.

The asphalt concrete 1 obtained by the present invention also has a flow value of the standard value (20 to 40 1/100 cm).
It's within.

On the other hand, in the case of the base layer and roadbed (upper layer), the optimum proportion of asphalt is smaller than in the case of the surface layer because the particle size of the aggregate is large. That is, as mentioned above, the base layer is composed of coarse-grained asphalt concrete with an asphalt content of 4.5 to 6%, and the upper subgrade is composed of 3.5 to 4% as a stabilizing agent.
A mixture of asphalt tort is generally used. However, in the case of the present invention, the amount of asphalt is 2 to 3%.
However, you can get something that fully satisfies these criteria. The amount of asphalt used in the base layer and roadbed is larger than that in the surface layer, and reducing the amount of asphalt has an extremely large economic effect. In addition, each layer (surface layer,
(base layer, roadbed) may be used, or it may be used in combination with conventional asphalt concrete. In particular, in the case of the surface layer, the product of the present invention may be used in the upper layer and the upper layer.

By the way, most asphalt concrete is currently manufactured using the hatch method, in which heated aggregates and fillers are put into a mixer equipped with a heating device, stirred and dried, and then a predetermined amount of asphalt is injected and stirring is continued. Make asphalt concrete.

Therefore, in the present invention, the resin component is melted in asphalt in advance, or it is put into a mixer together with aggregate and asphalt and melted. The polymerization initiator and surfactant are preferably added during or after asphalt injection. However, the proportion of resin, polymerization initiator, and surfactant in the total is extremely small, and it is necessary to measure them accurately. In the case of liquids such as emulsion resins and hydrogen peroxide solutions, metering can be carried out reliably by pump injection, but in the case of powders and pulverized materials, they must be measured one by one, making the operation complicated.

Therefore, the predetermined amount of resin, polymerization initiator, and surfactant required for one batch (for example, 1 ton of asphalt concrete) [for example, assuming 4% asphalt, 800 g of resin (
2% of asphalt), 100 g of polymerization initiator (0.25% of asphalt), and 400 g of surfactant (1% of asphalt) were mixed well and packed together in a bag as a ζ reinforcing additive, and injected into asphalt. By sprinkling the mixture into the mixer from time to time, it is convenient to handle and it is easy to obtain the correct mixing ratio. This reinforcing additive is determined depending on the type of asphalt concrete, the required stability, the type and particle size distribution of aggregate, the type of asphalt (plain asphalt or modified asphalt), grate, etc. It is necessary to select various types and ratios of surfactants and surfactants.

Next, the present invention will be explained in more detail with reference to Examples. Note that % indicates m1%.

Example 1 Heated 5-13 (JIS A 5001
), 35 kg of crushed stone, 25 kg of S-5 (crushed stone), 19 kg of screening, 12 kg of sand, and 5 kg of stone powder were respectively put into a mixer, kept at 170°C, and mixed for 10 seconds (dense particle size blend). Next, 4 kg of straight asphalt (penetration 69) heated to 170°C (4% of the total amount of aggregate and asphalt) and 80 g of strips of Boethylene agricultural waste film of 1 to 2 mm square (against asphalt) were added. 2%), 10g of sodium belloxoborate (Bun 1 asphalt 0.25%) was put into a mixer, and
After stirring for 0 seconds, 100.09 kg of heated asphalt mixture was obtained. A test piece was prepared using this mixture in a conventional manner, and the measurement results obtained are shown in Table 1 (■).

In addition, in addition to the above formulation, 10 g of solid nonionic surfactant "Emulgen J (ST-7, Kao ■!I!I)
(0.25% to asphalt), ■ Added polyethylene strips to 4% of asphalt, 01%
Added and ■Polyethylene strips to asphalt 4
% and sodium beloxoborate vs. asphalt 0.5
% of heated asphalt] and mixtures were prepared respectively. Test pieces were prepared using these mixtures in a conventional manner, and the measurement results obtained are also shown in Table 2.

Example 2 In a mixer, 96 kg of aggregate in the same proportion as in Example 1 was stirred and heated in the same manner as in Example], then 4 kg of straight asphalt heated in the same manner as in Example 1, and polychloride which was packed in a bag. Strips of vinyl film (1-2III
square) 80g (2% to asphalt), sodium beroxoborate log (?l asphalt 0.25%) and surfactant r Emulgen' 40H (total asphalt 1%)
The mixture was taken out of the bag, placed in a mixer, and stirred with a rod for 60 seconds to obtain 100.13 kg of heated asphalt mixture.

A test piece was prepared in the same manner, and the measurement results are shown in Table 1.

Comparative Example 1゜A heated asphalt mixture was obtained in the same manner as in Example 1■, except that sodium peroxoborate (polymerization initiator) was not used. The measurement results are shown in Table-1.

Comparative Example 2 4 kg of straight asphalt heated in the same manner as in Example 1 was mixed into aggregate (<96 kg in the same ratio as in Example 1) and stirred and mixed to obtain 100 kg of heated asphalt mixture. The measurement results are shown in Table-1.

Comparative Example 3 As aggregates, 35 kg of heated 5-13 crushed stone, 25 kg of S-5 crushed stone, 19 kg of screenings, and 12 kg of sand were used.

Put 5 kg of stone powder into a mixer and dry knead for 10 seconds while maintaining the temperature at 170'c. Hydrogen oxide water15.
3g (0.25% of asphalt) was poured into a mixer and stirred for 50 seconds to obtain 102.1453Kg of heated asphalt mixture.Similarly, the measurement results are shown in Table 1-1.

Comparative Example 4 A heated mixture of 100 K was obtained by performing the same operation using the same amount and proportion of aggregate (941 [g) as in Comparative Example 3 and the same amount of straight asphalt (6 Kg). Similarly, the measurement results are shown in Table-1.

Example 3 In a mixer, 96 kg of aggregate in the same proportion as in Example 1 was stirred and heated in the same manner as in Example 1, and then 4 kg of straight 1-asphalt heated in the same manner as in Example 1 and polypropylene packed in bags were added. A mixture of 80 g of crushed molded product (2% to asphalt) and sodium beloxoborate Log (0.25% to asphalt) was taken out of the bag, put into a mixer, stirred for 50 seconds, and the result was 100.0! lJK
g of heated asphalt mixture was obtained (■).

In addition, a heated asphalt mixture is obtained by mixing aggregate in the same proportion as in Example 1, heated asphalt, pulverized polypropylene molded product Table-1, and sodium peroxoborate in the proportions shown in Table-1, respectively (■ to ■ ). The results of each measurement are shown in Table-1.

Example 4゜95Kg of aggregate and asphal in the same proportion as Example 1) 5
kg, an equal composition of polyvinyl chloride film strips, styrofoam powder and polypropylene film strips 10
0g (2% based on asphalt), 12% each of sodium peroxoborate and 30% hydrogen peroxide as intermediate initiators.
．． 5g (0.25% based on asphalt)) and treated in the same manner as in the example to obtain a heated asphalt mixture.

Example 5゜96Kg of aggregate and 4K of asphalt in the same proportion as Example 1
g, 80 g (2% to asphalt) of an equal compound of polyvinyl chloride strips, expanded polystyrene powder, and polypropylene film strips (2% to asphalt), 10 g (0.25% to asphalt) of sodium peroxoborate as a polymerization initiator, and 30 g %
20 g of hydrogen peroxide solution (0.5% based on asphalt) was mixed in each and treated in the same manner as in Example 2 to obtain a heated asphalt mixture.

Example 6゜As a resin component, virgin resin powder of polyvinyl chloride (
A heated asphalt mixture was obtained in the same manner as in Example 1 (2), except that the same procedure as in Example 1 (2) was used, manufactured by Kanekabuchi Kagaku Kogyo 0 Kiku (polymerization degree 700).

Example 7: Polyvinyl chloride emulsion (trade name GE 351, active ingredient 50%) was used as the resin component, and the rest was as in Example 1.
A heated asphalt mixture is obtained in the same manner as in (2).

Example 8゜To 96 kg of aggregate in the same proportion as in Example 1, asphalt 4
Kg and putty-like polystyrene (IKg of foamed polystyrene was crushed appropriately, soaked in lacquer thinner No. 11 (containing about 50% toluene) to soften and melt, and kneaded well with a spatula) was dried in blocks and crushed. 800g (
Example 1 by adding 10g of sodium peroxoborate (0.25% to asphalt)
A heated asphalt mixture is obtained in the same manner as above.

Example 9゜coarse particle blended bone + 20% J'C3-20 crushed stone, S -
13 crushed stone 31%, S-5 crushed stone 22%, S, C 11%
, sand 11, stone powder 5%], asphalt 4% (based on the total amount of cut wood and asphalt), and asphalt 2%
Pulverized polypropylene molded product and asphalt 0.
25% I.Lium peroxoborate is treated in the same manner as in Example 1 to obtain a heated asphalt mixture.

Comparative Example 5゜As in Example 10, 5% of asphalt alone was mixed into the coarse-grained aggregate to obtain a heated asphalt mixture.

Example 10° Aggregate blend for upper roadbed (S-20 crushed stone 33%, 5-1
3 crushed stone 16%, S-5 crushed stone 14%, S, C 19%,
15% sand, 3% stone powder] and 3% asphalt (based on the total amount of aggregate and asphalt) Sodium beroxoborate is treated in the same manner as in Example 1 to obtain a heated asphalt mixture.

Comparative Example 6゜4% of asphalt was mixed into the aggregate having the same composition as in Example 10 to obtain a heated asphalt mixture.

The measurement results of Examples 4 to 10 and Comparative Examples 5 and 6 are shown in Table 2.

From the above results, it can be seen that the thermally engineered asphalt concrete obtained by the present invention exhibits excellent values in the Marshall stability test. In particular, in the case of dense-grained asphalt concrete, even if the amount of asphalt is reduced from 6% to 4% (reducing the cost by about 17%), the standard value at 6% is completely met, and the resin 5 polymerization initiator and Depending on the combination of surfactants, the ratio may be around 40% compared to the usual 6%. In addition, in the case of coarse particle size/stabilization treatment, asphalt m is 1 to 2% of the total compared to the conventional standard ratio.
Even if reduced, a material with sufficient practical strength has been created, making an extremely large contribution in terms of effective use of asphalt, cost reduction of asphalt concrete, and strength amplifier. .

On the other hand, regarding the resin, not only virgin resin powder, pellets, and emulsion, but also unnecessary resin molded products, so-called waste plastics, and pulverized products thereof can be effectively used, which is a major feature of the present invention. In addition, only a small amount of polymerization initiator and surfactant need be added to the asphalt, and no special equipment or techniques are required; conventional equipment can be used as is, and the production cost remains almost the same.

Furthermore, depending on the type of asphalt concrete, one batch of resin powder or pulverized polymerization initiator is required.

If the surfactant is mixed in a predetermined proportion and packaged in separate packages, it is extremely convenient to mix the surfactant accurately without having to measure it before use.

Claims (1)

[Claims] 1. Thermoplastic resin powders, pellets, emulsions, thermoplastic resin molded products, or pulverized products thereof, as well as mixtures thereof (pulverized polyvinyl chloride fat alone, putty-like polystyrene alone, and combinations of both) A process for partially or completely decomposing the aggregate (excluding mixtures) is carried out during or before mixing the aggregate and bituminous material, and the decomposed resin in the mixture is used to decompose the inorganic resin mixed in the mixture as well. 1. A method for producing asphalt concrete for paving, which comprises repolymerizing with a polymerization initiator and using the repolymerized resin and bituminous material as a binder for aggregate. . 2. The method for producing asphalt concrete for paving according to claim 1, wherein a peroxo acid salt is used as an inorganic polymerization initiator, and a surfactant is further added. 3. The method for producing asphalt concrete for pavement according to claim 1 or 2, wherein in the dense-grained asphalt concrete, 3.5 to 5.0% by weight of asphalt is used based on the total weight of the asphalt concrete. 4. An additive for reinforcing asphalt coiclete whose main components are thermoplastic resin powder or pulverized material and beroxo acid salt. 5. The additive material for reinforcing asphalt concrete according to claim 4, which contains a surfactant.