FI73714C - BELAEGGNINGSMASSA FOER GATOR, VAEGAR OCH PARKERINGSPLATSER OCH SAETT FOER FRAMSTAELLNING AV DENSAMMA. - 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

7371 4 1 Paving compound for streets, roads and car parks and method of making it

Beläggningsmassa för gator, vägar ooh parkeringsplatser och sätt för framstälining av densamma 5

The invention relates to a paving compound, especially for streets, roads, parking lots, etc., which mass is based on asphalt and contains e.g. a rock material with a low fines content of 10. The invention also relates to a method for producing such a coating composition.

Today's usual high speeds for road vehicles have made it necessary for rainwater to disappear quickly from the surface of the road. The most serious consequence of water on the roadway is aquaplaning, with the water film separating the tire from the roadway. Aquaplaning, which can already occur at relatively low speeds, is considered to be the cause of several serious traffic accidents. In other ways, too, water on the roadway can cause inconvenience, e.g., so that the car's Rois-20 tires need water upwards, which then impairs visibility.

Although a relatively rapid drainage of water can be achieved by making the road surface sloping, due to wear, especially when using studs in tires, and due to the compression and deformation caused by heavy traffic, depressed wheel grooves are formed in which water can accumulate despite the road is sloping.

Water-filled bike grooves increase the risk of aquaplaning and can turn into dangerous glaciers during the winter-30 in rapid temperature changes.

Another problem that has been particularly common in the construction of large asphalt or concrete paved parking lots is that these dense surface coatings interfere with natural absorption or drainage. Rainwater cannot penetrate through dense pavements and does not recover like groundwater, but accumulates as surface water, which in turn must be drained and 2 7 3 714 1 often also treated. Although the problem of aquaplaning does not normally occur in parking lots, they should be as free of water as possible because people have to ride on them.

5 The solution to the above-mentioned problems has been to cover the roadway, the parking lot and the like with a pavement with a high cavity content, so that the pavement thus becomes water-permeable. In the case of such coating masses, which consist of a rock material with asphalt as a binder and thus consist of a coarse material and a fine material, the coating mass is given a low content of fine material so that the mass has a large number of converging cavities. Thus, although only a portion of the cavity volume of the rock material is filled with asphalt or other fine material, there is a predetermined cavity volume remaining in the finished coating mass. This voids content is at least 15-25% in well-draining masses compared to normal non-draining coating masses, which according to the (Swedish) regulations in force must have a void volume of 2-6%.

20 Experience with such so-called ABÖ (Opengrades Asphalt Friction Courses) has shown that such pulps have a number of other good properties in addition to the dewatering properties mentioned. Of these, it should be noted that they give high friction and quiet running against rubber tires. Road markings are better seen and last longer. Especially at night, these types of wet coatings reflect less than conventional dense coatings.

However, ABÖ pulps also have certain disadvantages. Due to their porosity, ABÖ masses 30 cannot be placed anywhere, e.g. on cracks on the substrate. Special rules must also be taken into account when investing. However, where so-called ABÖ masses are needed, they have mostly positive properties overall. 1

II

However, there are major problems in the manufacture of such water-dissipating coating compositions. At the temperature used in the normal mixing of rock mass and asphalt, which is 150 ~ 160 ° C for asphalt with a temperature amer-120 or Α-135 (at 500 cSt), asphalt flows out of the rock because there are not enough fine grains. to retain easily draining asphalt. The runoff of this asphalt leads to e.g. "Avkorning" or separation in handling, transport and coating so that the coarser granules separate from the finer granules and cause so-called stone discharge in the finished coating, all due to the fact that the coating mass cannot be contained enough. asphalt.

10 To solve this problem, attempts have been made to perform mixing at a lower temperature. It has been found that at a mixing temperature of about 115-120 ° C, such a small asphalt runoff from the rock material is obtained that water-draining paving masses can be made with a sufficiently high asphalt content so that no substantial granule removal or any substantial stone release occurs. However, the low stirring temperature has caused new problems. In order to eliminate the effect of residual moisture in the stone material, which prevents the asphalt from wetting the stone surfaces, it is necessary to add e.g. wetting agents. Until now, amines prescribed for this purpose have been used, e.g. e.g. alkylamine, e.g. "LILAMIN VP 75", about 0.4% based on the amount of asphalt. However, amines emit an unpleasant odor both during the production of asphalt in an asphalt plant and during the application of coating mass.

Slaked lime has also been used, for example 1.5% of the amount of aggregate, to eliminate residual moisture in the aggregate.

However, since both amines and slaked lime are classified as hazardous substances, certain safety precautions must be taken when using these substances. The low mixing temperature of asphalt and rock material also requires a time-consuming and expensive reorganization of the asphalt plant. The low temperature mixed coating mass also has an unfavorable tendency to post-compact or compress, which, especially in summer, is manifested in heavy traffic, partly by the formation of relatively strong wheel grooves, and partly also by the post-compacted part of the pavement.

7 3 71 4 4 1 even surface compression, which results in a reduction in the water removal capacity of the coating exactly where it is best needed.

It has previously been proposed to increase the viscosity of the asphalt binder by adding a fine-grained filler material. According to Swedish patent 211,163, a very high effect per unit weight is obtained if the filler material consists of mineral fibers with a diameter of 5-15 μm. An increase in viscosity by mixing the filler material results in less asphalt runoff from the rock material, but it has been self-evident to one skilled in the art that increasing the viscosity by adding the filler material produces the same post-compaction problem as increasing the viscosity by lowering the temperature. The method proposed in the patent has therefore not been used to any greater extent.

It has now been surprisingly shown that the use of mineral fibers with special dimensions can solve both of the above problems, i.e. partly avoiding asphalt runoff from the rock material, partly also avoiding the cumbersome post-compaction problem, and this is also possible when mixing asphalt at normal mixing temperature 150-160 °. C. This has proven possible if a sufficiently large amount of fibrous material with sufficiently thin fibers is introduced into the asphalt phase and mixing takes place at a normal asphalt mixing temperature of 150-160 ° (.,. The addition of fibers does not affect the adhesion of asphalt and rock material, and this means that no special Since the temperature is kept at a normal level during mixing, no time-consuming and complicated rearrangements need to be made in the asphalt plant, and it has been shown that this type of coating composition gives perfectly acceptable values in terms of post-compaction and compression. Thus, the above-mentioned problem of surface compression of the coating composition and thus the reduced dewatering capacity caused by the pressure of the wheels of the vehicle is substantially eliminated or reduced.

Except that the added fibrous material must have a certain small average diameter, the fibers must be flexible and must not soften at the mixing temperatures used. It has been shown that particularly good results are obtained with mineral fibers having an average fiber diameter of less than 5 and more than 1.

The invention is characterized by what is stated in the claims.

Experiments have shown that fibers coarser than 5 μm do not have a sufficient viscosity-increasing effect, nor do they clearly strengthen the finished binder film as well. The latter can possibly be elucidated in such a way that they tend to be oriented far too much parallel to the plane of the stones and thus also in the plane of the binder film.

On the other hand, if an average fiber diameter smaller than 1 μm is used, the viscosity is affected, but the reinforcing effect is poor. Thus, a range of 1 to 5 μm for the average diameter appears, which seems optimal in this context.

And it has also proved advantageous if the mineral fibers can be made to appear separated from one another in the asphalt phase so that they do not form knots or blockages. The presence of such knots or blockages can be prevented by adding the fibers in a suitable manner and by pre-treating the fibers with a substance which helps the asphalt to moisten the fibrous surface. Wetting agents known per se, e.g. cationic ten-binders, can be used for this purpose. Wetting of the fiber surfaces of Asia.'t can also be promoted by; all moisture is removed from the fibers by drying them before adding them to the asphalt mass.

The mixing of the fibrous material into the asphalt preferably takes place before the addition of the rock material. Good and unobstructed mixing can be achieved if the asphalt is heated during mixing of the fibers to a temperature of, for example, 20-40 ° C for mixing the aggregate above normal temperature and that the asphalt-fiber mixture is cooled to 35 ° C before adding the aggregate to said normal mixing temperature. This temporary increase in temperature has a particularly good effect in the event that the wettability between the asphalt and the fibers 7371 4 b 1 is improved by treating the fiber surfaces with a wetting agent or by drying the fibers. Due to the risk of ignition at elevated temperatures, the process must take place in a closed manner. The invention therefore relates to an asphalt-based coating in a stereo and to a method for producing such a coating composition having dewatering properties and comprising a rock material with a low content of fine material and with asphalt as a binder. In the process according to the invention, the mixing of the rock material takes place at an asphalt temperature of 150 to 160 ° C and in the presence of 0.5 to 20% by weight of the fibrous material, based on the amount of asphalt which does not dissolve or soften in the asphalt.

Experiments have shown that aile 0.5% does not produce a sufficiently large effect to be technically and economically meaningful, 15 s.o. would motivate blending and fiber costs. Furthermore, experiments have shown that concentrations higher than 20% do not produce improved properties corresponding to the cost of larger amounts of fiber.

The following are some examples of the invention. It is to be understood, however, that these examples illustrate the nature of the invention and that the invention is not to be limited except by the claims.

Example 1 25

> .144 kg of rock material with the following average size distribution was fed to the asphalt mix batch mixer: <2 mm 7% 30 2-4 mm 18%: 4-8 mm 24% 8-12 mm 51%> 12 mm 0% 1

II

The rock material was heated to 160 ° C. 160 kg of asphalt with a thermal temperature of A-135 was added at 160 ° C through 40 nozzles. Shortly before the asphalt was added to the rock material, 32 kg of 1,73714 l of mineral fibers bearing the trademark "1N0RPHIL 057", manufactured by Rockwool AB, were added. "INORPHIL 057" is a mineral fiber material having an average fiber diameter of about 3 microns and having a major fiber content of 1-5 microns. There is no acceptable direct method for determining length. Preferably, the so-called thickening number (n 2) is measured instead, which consists of the equation * n = - * - f% 10 where η is the viscosity of the slurry with 0.5 kg of dry fibers in 200 ml of ethylene glycol at 20 ° C , and 7 is the viscosity of the same ethylene glycol without fibers also at 20 ° C and measured with the same apparatus, a Brookfield viscometer with a spindle LV 1 or the like. The thickening number 1.8-6.0 applies to INORPHIL 057.

15

At the end of the mixing, the mass was removed and the runoff of the asphalt from the rock material was studied and evaluated. The evaluation, which took place according to the scale below, showed a clear acceptable result, point B below. Post-compaction was judged to be sufficiently low for this type of water-dissipating coating composition and was shown to correspond to normal post-compaction of conventional non-effervescent coating compositions.

Asphalt runoff from the rock material was determined as follows: 25,100 g of pulp was removed and placed with a minimum treatment on a round heat-resistant glass plate with a diameter of 203 mm. the glass plate was placed in an oven at 160 ° C and examined after 60 minutes from below. The following grading criteria were used: A asphalt only at the point of contact between stone and glass B small asphalt angles at each point of contact C several larger asphalt angles at a few points of contact 35 p larger asphalt angles at each point of contact 7371 4 s 1 Examples 1 16, 6.4, 1.3 and 0.65 kg of mineral fibers 5 "INORPHIL 057" were added, respectively. The results are shown in the table below. It is seen that the addition of less than 0.5% of mineral fibers resulted in insufficient runoff and, in addition, an unsatisfactory post-compaction value in the finished asphalt mass.

10 Example 6

3,168 kg of rock material with the same size distribution as in Example 1 was fed to the batch mixer for the asphalt mixes. The rock was heated to 160 ° C. At the same time, 166 kg of asphalt with a thermal temperature of Λ-135 was heated in the frix to 160 Cm 15, and 16 kg of the same mi joy was added to the heated asphalt! i <fibers as in Example 1. The asphalt and mineral fibers were mixed and added to the rock material heated at the same temperature, and all were mixed together.

20

The runoff was monitored and evaluated in the same manner as in Example 1. Despite the lower amount of mineral fibers in the coating pulp, there were the same runoff and ice; ki tight sea buckthorn somina! as in Example 1.

25

Examples 7-8

The same procedure as in Example 6 was repeated, except that 1.3 or equivalent was added instead of 6.4 kg. 0.65 kg of mineral fibers of the same type as in Example 6. The results are shown in the table below. It is seen that also in this case the addition of less than 0.5% of mineral fibers gives an unsatisfactory result.

Example 9

The procedure of Example 6 was repeated, except that the asphalt was heated to 190 ° C before mixing the mineral fibers, and in this case the same amount of mineral fibers of "INROPH1L 057" as in Example 6 was added. Mixing of asphalt and mineral fibers cooled to 160 ° C before mixing the rock material.

5

The results are shown in the table.

Examples 10-11 The procedure of Example 9 was repeated, but in these cases 1.3 and resp. 0.65 kg of mineral fibers. The result presented in the table confirms that adding less than about 0.5% of mineral fibers, calculated on the amount of asphalt, does not produce a satisfactory result.

15 Drainage was considered and evaluated in the same way as in the previous examples, and the coating composition had the same good properties as in the previous examples.

Thus, by heating the asphalt mass additionally in connection with the mixing of the mineral fibers, the amount of mineral fibers could be further reduced without deteriorating the runoff and post-compaction properties.

Example 12 For comparison, the method of claims 1-5 was repeated, but instead of "INORPHIL 057" mineral fibers, mineral fibers having an average fiber diameter of 6-8 μm are added here. The runoff and post-compaction properties were considered in the same manner as in the previous examples. The coarse fibers were prepared by separating all non-fibrous material and some of the fibers less than 5 .mu.m from the hard 30 wool fiber basalt wool. The runoff proved to be greater than in Examples 1-5 and was not judged acceptable (D), cf. the table below.

35 Example 13

The procedure of Example 1 was repeated with the mineral fiber material m 73714 ^, whose average fiber! the diameter was less than 1 pm. The flow and compaction properties were considered, and the flow did not prove to be acceptable (h), and the compaction properties were significantly higher than in Examples 1-5.

5

The table on the next page clearly confirms the relationship between the fiber roughness and the runoff of the asphalt-stone-fibrous material and thus also between the fiber roughness and the porosity and water permeability of the finished coating composition. Thus, it is clearly seen that fibers with a coarser diameter than about 5 have worse runoff values than fibers with a diameter of 1-5.

15 20 25 30 35 11 7371 4 1 Table __ -, -— i '

Pre- Fiber Type · Fiber Amount Leakage | Post-seal mark kg% asphalting 5________ 1 IN0RPH1L 057 32 20 A normal 2 "16 10 B normal 3" 6.4 4.0 C normal 4 "1.3 0.8 D certain tendency 10 5" 0.65 0, 4 E clear tendency 6 INORPHIL 057 6.4 4.0 B normal 7 "1.3 0.8 C normal 8" 0.65 0.4 j D / E certain tendency 9 INORPHIL 057 6.4 4.0 B j normal j! 15 10 "1.3 0.8 C normal i 1

1 I

11 "0.65 0.4 D 1 certain tendency 1 I!! 12 coarse fiber 16 10 D / E certain tendency i j 13 ground j IN. 057 16 10 E clear tendency i: 20 L — J __; _ 1: 25 30 35

Claims (8)

12 7371 4 1 Claims 1. Paving compound for streets, roads and car parks, which has a dewatering effect and consists of a mixture of aggregate and asphalt, characterized in that the aggregate has an average particle size of 2-12 mm, that about 50% of the aggregate has an average particle size j0 8-12 mm, that the coating mass contains 0.5-20% by weight of mineral fibers based on the amount of asphalt, 15 and that the average diameter of the mineral fibers is between 1 and <5 μm. Coating composition according to Claim 1, characterized in that the mineral fiber material is treated with a wetting agent, e.g. a cationic surfactant. 20 A method for producing a coating composition according to claim 1 or 2, having water-dissipating properties and consisting essentially of a mixture of aggregate and asphalt, characterized in that the aggregate has an average particle size of 1-12 mm and about 50% of which has an average particle size. 8-12 mm is mixed with the asphalt at a temperature of 140-170 ° C or preferably 150-160 ° C in the presence of a mineral fiber material which is about 0.5-20% by weight of the amount of asphalt and which is such that it does not dissolve or soften in asphalt having an average diameter between 30 l and <5 pn and in that the mineral fiber material is mixed so that the mineral fibers are substantially evenly distributed and separated from each other in the asphalt mass. b. A method according to claim 3, characterized in that the mineral fiber material is mixed with the asphalt before the asphalt is mixed with the rock material. 13 7371 4 Method according to one of Claims 3 to 4, characterized in that the mineral fibrous material is treated with a wetting agent, e.g. a cationic surfactant, before the fibrous material is mixed into the asphalt phase. 5 Method according to one of Claims 3 to 5, characterized in that the fibrous material is completely dried before it is mixed into the asphalt phase. A method according to claim 5, characterized in that the asphalt is heated above about 20-40 ° C above the mixing temperature of the asphalt and rock material, after which the mineral fiber material is mixed with the asphalt, and the mixture of asphalt mineral fiber material is cooled to the rock material temperature and mixed with the rock material. 15 20 25 30 35 ___ r ~ 7 3 71 4 u