DK152713C - COATING PREPARATION FOR ROADS, ROADS, PARKING PLACE R, AND MORE AND PROCEDURE FOR PREPARING COATING. - Google Patents

Abstract

A surfacing mass especially for outdoor use and mainly comprising a mixture of asphalt and a stone material having a low content of fine material. The mixture comprises a little amount of fibres of a type which is not solved or softens in the asphalt, preferably mineral fibres. The fibre material has an average diameter of between 1 and 5 mu m and is added in an amount of between 0,5 and 20% by weight calculated on the amount of asphalt. The invention also relates to a method of manufacturing such surfacing mass at a mixing temperature of 140-170 DEG C or preferably 150-160 DEG C both for the asphalt and the stone mass. Preferably the fibre material is admixed in the asphalt before the mixing thereof with the stone material. The fibre material may be admixed in the asphalt at an asphalt temperature which is higher than the mixing temperature for asphalt and stone material.

Description

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BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a coating composition with drainage effect for streets, roads, parking lots and more consisting of a mixture of stone material, bitumen (asphalt) and a fiber material. The invention also relates to a process for preparing such a coating composition with drainage properties.

The now usual high speeds for vehicles have created a need for rainwater to quickly disappear from the surface of the roadway. The most serious consequence of water on the roadway is aquaplaning, whereby a vehicle tire is separated from the waterway by a water film. Aquaplaning, which is already occurring at relatively low speeds, is considered to be the cause of several serious traffic accidents. In other ways, water on the roadway can cause problems, for example by car tires spraying water and impairing vision.

A fairly rapid drainage of water can be achieved by designing the roadway rounded, but due to wear, especially when using tire tires, and due to the packing and deformation caused by heavy traffic, recessed wheel tracks where water can be congregate despite the roadway being established.

Of course, the water-filled wheel tracks increase the risk of aquaplaning and can, during winter time, be transformed into treacherous ice patches by winter.

Another problem that has arisen in particular in the construction of large asphalt or concrete covered parking spaces is that these dense surface coatings cause disturbance in the natural percolation or drainage. The rainwater is unable to penetrate the dense coatings and thus is not returned as groundwater, but is collected as surface water, which in turn must be diverted and even often purified. Although there are usually no problems with aquaplaning in parking lots, these should be as water-free as possible, as humans must walk there.

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One solution to the aforementioned problems has been to provide the roadway or parking lot with a large void content so that the coating thereby becomes water permeable. For such coating compositions, which consist of stone material with bitumen and binder, and thus consisting of coarse and fine material, the coating material has been given a low content of fine material, so that the mass has a large number of communicating voids. Thus, since only part of the void volume of the rock material is filled with asphalt or other fine material, a certain void volume remains in the finished coating material. This void volume is in well-draining masses of at least 15-25%, which should be compared with normal non-draining coating compositions, which according to current (Swedish) regulations must have a void volume of 2-6%.

The experience with so-called ABØ masses (English: open-grade asphalt friction courses) has shown that, in addition to the drainage properties mentioned, such masses have several other good properties. Among these, it is noted that they provide high friction and quiet driving against rubber tires. Road markings are better seen and longer resistant to wear. Especially at night, both coatings of this type give less reflexes than the traditional dense coatings.

However, the ABO masses also have certain drawbacks: Because of their porosity, ABO masses cannot be laid anywhere, eg on cracked substrates. The interpretation also requires that special rules be observed. However, where the so-called ABØ masses are needed, they have overall positive properties.

However, the production of such drainage coating compositions presents major problems. At normal temperature for mixing the rock mass and the bitumen, which for the bitumen with the temperature designation A-120 or A-135 (at 500 cSt) is at 150-160 ° C, the bitumen (asphalt) runs off the stones, as there are not enough fine particles grain for 3

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to retain the easily liquid bitumen. This drainage of the bitumen leads, among other things, to for "culling" or segregation by handling, transport and laying, with coarser grains being separated from finer grains and giving rise to so-called stone grinding in the finished coating, which is all because the coating variety cannot be made to contain enough bitumen.

To solve this problem, the mixture has been tried at lower temperature. It has been found that at a mixing temperature of 115-120 ° C, a bit of drainage of bitumen is obtained from the rock material so that drainage coating compositions having a bitumen content sufficiently large to produce no significant drainage can be produced. some significant stone slip. However, the low mixing temperature has caused new problems. In order to eliminate the influence of residual moisture in the rock material, which prevents the bitumen from wetting the stone surfaces, one must, inter alia, add a moisturizing enhancer. Hitherto, certain amines have been used for this purpose, for example an alkylamine in an amount of about 0.4% based on the amount of bitumen. However, amines emit an unpleasant odor both in the production of bitumen at the asphalt plant and in the laying of the coating material.

Slaked lime in an amount of, for example, 1.5% based on the amount of rock material has also been used to eliminate the residual moisture in the rock material.

However, since both amines and soda lime are classified as harmful substances, special precautions must be observed when using these agents. The lower mixing temperature for asphalt and stone material also requires a time-consuming and costly conversion of the asphalt plant. The low temperature mixed coating composition also exhibits a disadvantageous tendency for packing or compression, which is particularly evident in the summer time due to heavy traffic loads, partly due to the occurrence of 4

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relatively strong wheel grooves, and partly know that the post-packed portion of the coating gets a condensation, especially of the surface, which causes the drainage ability of the coating to be reduced precisely where it is most needed.

It has previously been suggested by increasing the viscosity of asphalt binder by the addition of a fine grained feed material. According to Swedish patent specification no. weight unit has a particularly large effect if the filling material is made up of mineral fibers with a diameter of 5-15 μια. An increase in the viscosity of admixture of filler material results in less asphalt drainage from the rock material, but it is obvious to those skilled in the art that an increase in viscosity by admixture of filler material would cause the same packing problem as an increase in viscosity by lowering the temperature. Therefore, the method proposed in the patent has not been used to any great extent.

It has now surprisingly been found that both of the above-mentioned problems can be solved, that is, partly to avoid bitumen drainage from the rock material and partly to avoid the troublesome post-packing problem, and this is possible even at this mixture at the normal mixing temperature of 150-160 ° C.

The coating composition according to the invention, which is of the type mentioned initially, is characterized in that the rock material has such a low content of fine material that the coating mass has a relatively large number of communicating voids with a void volume in the coating mass of at least 15%, preferably 15%. 25%, that the rock material mainly contains rock particles with an average diameter of between 2 and 12 mm, with approx. 50% of the rock material has a particle size of between 8 and 12 mm, that the fiber material in the coating mass is of a type that is not dissolved or softened in bitumen (asphalt) and which has an average fiber diameter of approx. 3 µια, the majority of the fibers being in the range of 1-5 µm, the fiber material being treated with a wetting agent, e.g. a cationic 5

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surfactant, and that the fiber material is present in an amount of between 0.5 and 20% by weight, calculated on the basis of the bitumen content (the amount of asphalt).

Such a coating composition can be prepared in accordance with the invention in that rock material having a low content of fine material, which stone material mainly contains stone particles with an average diameter of between 2 and 12 mm, with approx. 50% of the rock material has a particle size of between 8 and 12 mm, is mixed with bitumen (asphalt) at a temperature of 140-170 ° C, typically at the normal mixing temperature of 150-160 ° C, in the presence of between 0, 5 and 20% by weight - calculated on the basis of the amount of bitumen (asphalt) - of a fiber material of a type which does not dissolve or soften in the bitumen (asphalt) and which consists of mineral fibers with an average fiber diameter of approx. 3µιιι, the majority of the fibers being in the range of 1-5-μιη so that the mineral fibers are mixed in such a way that they are substantially evenly distributed and exposed to each other in the coating material and that the fiber material is treated with a wetting agent. The adhesion between bitumen and rock material is not affected by the fiber admixture, which means that no special adhesive enhancers need be added. Since the temperature below the mixture is kept at normal level, no time-consuming and complicated adjustments have to be made at the asphalt plant, and it has been found that a coating composition of the type mentioned gives perfectly acceptable values in terms of packing or compaction. This eliminates or substantially reduces the above-mentioned problem of densification of the surface of the coating composition and thus the reduced drainage capacity due to the pressure from the vehicle wheels.

In addition to the requirement that the added fiber material should have a certain medium diameter, it is also required that the fibers be durable and must not be softened at the actual blending temperature. It has been found that special 6 is obtained

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good results with mineral fibers having an average fiber diameter of less than 5 μιη and more than 1 μη. Tests have shown that fibers coarser than 5 μιη do not have a sufficient viscosity enhancing effect and do not appear to be as good for the finished binder film. The latter can possibly be explained by the fact that they tend to be too much inclined to orient themselves in parallel with the stones and thus also in the plane of the binder film. On the other hand, if fibers with a mean diameter of less than 1 μιη are used, the viscosity is affected, but the reinforcing effect is poor. Thus, there is a range of 1-5 μιη for the mean diameter, which in this context seems optimal.

It has also been found to be advantageous if the mineral fibers can be made to separate separately in the bitumen phase so that they do not form knots and tufts. The occurrence of such nodes or tufts can be prevented by interfering with the fiber material in the bitumen (asphalt) before mixing the bitumen with the rock material. Since the fibers have already been treated with a wetting agent known per se, e.g. cationic surfactant, before the fiber material is mixed into the bitumen phase, the mixing of fibers is further facilitated.

The wetting of the bitumen by the fiber surfaces can also be facilitated by removing all moisture from the fibers by completely drying the fiber material before admixing it into the bitumen phase.

The mixing of the fiber material in the bitumen (asphalt) takes place appropriately before the rock material is added. A good and two-free admixture can be obtained if the bitumen in connection with the admixture of the fibers is heated to a temperature of, for example, 20-40 ° C above the normal mixing temperature for bitumen and stone material, after which the fiber material is cooled to the temperature of the stone material and mixed with the stone material.

This temporary temperature rise has a particularly good effect 7

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in that case, the wetting ability between bitumen and fibers has been improved by the fiber surfaces having been treated with some wetting agent or by the fibers being dried. Due to the risk of ignition at the elevated temperature, the process should be closed.

Tests have shown that at less than 0.5% of the fiber material, a sufficiently large effect is not obtained to make it technically economically interesting, ie. can motivate the blending and fiber costs. Furthermore, experiments have shown that a content higher than 20% does not provide enhanced properties that offset the cost of extra fibers.

In the following, some examples of the invention will be given.

EXAMPLE 1 In a bitumen mass charge mixing plant, 3144 kg of a rock material having the following average size distribution was introduced: <2 mm 7% 2-4 mm 18% 00 1 tf mm 24% 8-12 mm 51%> 12 mm 0%

The rock material was heated to 160 ° C. 160 kg of bitumen with the designation temperature A-135 were fed at 160 ° C through 40 nozzles. Shortly before the introduction of the bitumen, the rock material was added to 32 kg of mineral fibers of the type under the trade name INORPHIL 057 "and manufactured and marketed by Rockwool AB." INORPHIL 057 "is a mineral fiber material whose average fiber diameter is about 3 μια and most of the fibers are in the range of 1-5 μκι. For characterization of the length there is no 8

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acceptable direct methods. Instead, one can appropriately measure the so-called thickening number (nf) that is made up of

Where η is the viscosity of a slurry of 0.5 g of dry fiber in 200 ml of ethylene glycol at 20 ° C, and η0 is the viscosity of the same ethylene glycol without fibers, also at 20 ° C and measured with the same equipment, namely a Brookfield -viscimeter with spindle LV 1 or equivalent. For INORPHIL 057, the thickness number is 1.8-6.0.

After mixing was completed, the pulp was withdrawn and the effluent of the bitumen from the rock material was observed and evaluated. The assessment made according to the scale below showed a clearly acceptable result, point B below. The post-pack was judged to be low for a drainage coating composition of this type and was found to be similar to the normal post-pack for conventional non-drain coatings.

The effluent of the bitumen from the rock material was determined as follows: 1000 g of the pulp was taken out and placed with a minimum of handling on a circular heat-resistant glass plate with a diameter of 203 mm. The glass plate was placed in a heating cabinet at a temperature of 160 ° C and viewed from below after 60 minutes. The following rating scale was used: A bitumen only at the contact points between stone and glass.

B small bitumen clumps at each contact point.

C several major bitumen blisters at some of the contact points.

D larger bitumen clumps at each contact point.

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EXAMPLES 2-5

The same method is used as in Example 1, but with the difference that 16, 6.4, 1.3 and 0.65 kg of mineral fibers of type "INORPHIL 057" are added respectively. The result is given in 5 in the table below. It appears that a smaller addition of mineral fibers than approx. 0.5% gave a deficient run-up and also an unsatisfactory value for packing in the finished asphalt pulp.

EXAMPLE 6 10 In a charge mixer for asphalt pulp, 3158 kg of a rock material of the same size distribution as in Example 1. was introduced. The stones were heated to 160 ° C. Separately, 166 kg of bitumen were heated simultaneously with the designation temperature A-135 to 160 ° C, and to the hot bitumen 16 kg of 15 mineral fibers of the same type as in Example 1 were added. The bitumen and mineral fibers were mixed and added at maintained temperature to the heated rock material, and it was all mixed.

The drainage was observed and evaluated in the same way as in Example 1. Despite the smaller amount of mineral fibers, the coating mass showed the same drainage and post-packing properties as in Example 1.

EXAMPLES 7-8

The same method as in Example 6 was repeated with the difference that instead of 6.4 kg, 1.3 and 0.65 kg of mineral fibers of the same type as Example 6 were added, respectively. The results are given in the table below. It can be seen that even in this case, the addition of mineral fibers of less than approx. 0.5% unsatisfactory result.

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EXAMPLE 9

The procedure of Example 6 was repeated but with the difference that asphalt was heated to 190 ° C prior to the mixing of the mineral fibers and in this case mineral fibers of type "INORPHIL 057" were added in the same amount as in Example 6. The mixture of bitumen and mineral fibers were cooled to 160 ° C prior to mixing with the rock material.

The result is given in the table.

EXAMPLES 10-11

The procedure of Example 9 was repeated, but in this case 1.3 and 0.65 kg of mineral fibers were added, respectively. The result given in the table confirms that an addition of mineral fibers of less than approx. 0.5% based on the bitumen content gives an unsatisfactory result.

The run was observed and evaluated in the same way as in the previous examples, and the coating mass was found to have the same good properties as in the previous examples.

Thus, by the additional heating of the bitumen mass in connection with the admixture of the mineral fibers, the amount of mineral fiber could be further reduced without deteriorating the drainage and post-packing properties.

EXAMPLE 12

In comparison, the procedure of Examples 1-5 was repeated, but instead of the mineral fibers "INORPHIL 057", mineral fibers with an average fiber diameter of 6-8 μιη were added here. Of the running and post-packing properties were observed in the same way as in the previous examples. The coarse fibers were prepared by starting from coarse fiber 11

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basaltic duty separated and removed all non-fibrous material and a portion of the fiber below 5 μιη. The drains were found to be larger than in Examples 1-5 and judged to be unacceptable (D), see the table below.

EXAMPLE 13

The procedure of Example 1 was repeated but with a mineral fiber material whose average fiber diameter was less than 1 μπι. The drainage and backpacking properties were observed and the drainage was found to be non-acceptable (E) and the backpacking properties were significantly higher than in Examples 1-5.

The table below clearly reinforces the connection between the fiber roughness and the run-off occurrence of the bitumen stone material and thus also the connection between the fiber roughness 15 and the porosity and water permeability of the finished coating. Thus, it is clear that fibers with a diameter larger than approx. 5 μι has a lower value of running value than fibers within the range 1-5 μπι.

Claims (6)

1. Drainage paving, for streets, roads, parking lots and more, consisting of a mixture of rock material, bitumen (asphalt) and fiber material, characterized in that the rock material has such a low content of fine material that the coating mass is relatively large. number of communicating voids having a void volume in the coating mass of at least 15%, preferably 15-25%, that the stone material contains mainly stone articles with an average diameter of between 2 and 12 mm, with approx. 50% of the rock material has a particle size of between 8 and 12 mm, that the fiber material in the coating mass is of a type that is not dissolved or softened in bitumen (asphalt) and which has an average fiber diameter of approx. Most of the fibers are in the range of 1-5 mm, that the fiber material is treated with a wetting agent, eg a cationic surfactant, and that the fiber material is present in an amount of between 0.5 and 20% by weight calculated on the basis of the bitumen amount (asphalt amount). Process for the preparation of a coating composition with drainage properties according to claim 1, comprising a mixture of rock material, bitumen (asphalt) and fiber material, characterized in that rock material with a low content of fine material, which mainly contains rock particles with an average diameter of between 2 and 12 mm, with approx. 50% of the rock material has a particle size of between 8 and 12 mm, mixed with bitumen (asphalt) with a temperature of 140-170 ° c in the presence of between 0.5 and 20% by weight - calculated on the basis of the amount of bitumen (asphalt) - of a fiber material of a type which does not dissolve or soften in the bitumen (asphalt) and which is made up of mineral fibers with an average fiber diameter of approx. 3 microns, the majority of the fibers being in the range of 1-5 microns so that the mineral fibers are blended in such a way that they are substantially evenly distributed and exposed to each other in the coating composition, and that the fibrous material is treated with a wetting agent. Process according to claim 2, characterized in that the fibrous material is mixed into the bitumen (asphalt) before the bitumen is mixed with the stone material. DK 152713 C Process according to claim 2 or 3, characterized in that the wetting agent is applied to the fibrous material before it is mixed into the bitumen phase (asphalt phase). Process according to any one of claims 2-4, characterized in that the fibrous material is completely dried before being mixed into the bitumen phase. Process according to Claim 4, 10, characterized in that the bitumen (asphalt) with mixed fiber material is heated to a temperature of about 20-40 ° C above the mixing temperature of bitumen and stone material, after which the bitumen is cooled to the temperature of the stone material and mixed with the stone material.