Method for the Production of Cold-Process Bituminous Coatings

Abstract

A method is shown for preparing cold-process bituminous coatings, in particular the preparation of wear surface dressings which method includes the steps of preparing a bituminous binder as a cationic emulsion of bitumen; preparing an aggregate comprising at least one first aggregate fraction; and forming said cold-process bituminous coating formed with at least said aggregate interpenetrated into said binder; characterized in that said step for preparing said aggregate comprises a step for coating said at least one first aggregate fraction with lime.

Claims

1. A method for preparing cold-process bituminous coatings, in particular of wear surface dressings (WSD), comprising the steps of: (a) preparing a bituminous binder as a cationic emulsion of bitumen, (b) preparing an aggregate comprising at least one first aggregate fraction, and (c) forming said cold-process bituminous coating formed with at least said aggregate interpenetrated into said binder; characterized in that said step for preparing said aggregate comprises a step for coating said at least one first aggregate fraction with lime.

2. The preparation method according to claim 1, comprising: (i) at least one bringing of said bituminous binder onto a surface to be coated, in order to form a binder layer on said surface to be coated, (ii) at least one bringing of said aggregate onto said surface to be coated, before or after said bituminous binder, and wherein said bituminous coating is formed with at least one layer of said aggregate interpenetrated in said bituminous binder.

3. The preparation method according to claim 2, wherein said bituminous coating is formed with at least one layer of said interpenetrated aggregate said aggregate interpenetrated in said bituminous binder comprises asymmetrical or symmetrical number of layers of bituminous binder and of aggregates possibly alternately.

4. The preparation method according to claim 1, wherein: (i) said bituminous binder is brought into a kneader, (ii) said aggregate is brought into said kneader, during, before or after said bituminous binder, and (iii) said bituminous coating is formed with the mixture of said aggregate interpenetrated into said binder and is applied on a surface to be coated.

5. The preparation method according to claim 1, wherein said step for coating said at least one first aggregate fraction comprises application of a lime composition on said at least one first aggregate fraction by immersion, soaking, vaporization, spraying or mixing in an amount of a lime content from 0.05 to 2% by weight expressed in hydroxide equivalent (Ca(OH).sub.2 and/or Mg(OH).sub.2) based on the total weight of aggregate.

6. The preparation method according to claim 1, wherein said lime is selected from the group consisting of calcium hydrated limes, dolomitic hydrated limes, hydrated magnesias, calcium-magnesium hydrated limes, quick calcium limes, magnesia, calcium-magnesium or dolomitic quick limes, quick limes with retarded reactivity, including partly pre-hydrated limes, over-baked quick limes, partly slaked limes with exogenous additives and mixtures thereof, filter dusts, flying ashes, including calcium ashes, Portland cements, hydraulic limes, construction limes as defined in the EN 459-1 standard, and mixtures thereof.

7. The preparation method according to claim 5, wherein said lime composition is a solid composition or a suspension such as a lime milk or a lime slurry.

8. The preparation method according to claim 1, wherein said coating step further comprises a step for bringing an aqueous phase.

9. The method according to claim 1, wherein said aggregate is selected from the group consisting of gravels, sands and fillers, artificial aggregates, including aggregates stemming from deconstruction, special aggregates, aggregates of by-products from other industries and mixtures thereof.

10. The method according to claim 1, wherein said aggregate belongs to a granular class d/D expressed according to the EN 13043 standard, in terms of lower d and greater D sieve dimensions (in mm) from 0/4 to 0/30, in particular a granular class selected from the group consisting of the granular classes of 0/4, 0/6, 0/8, 0/10, 0/14, 0/20, 0/30 and mixtures thereof.

11. The method according to claim 1, wherein said aggregate belongs to a granular class d/D expressed in terms of lower d and greater D sieve dimensions from 2/4 to 10/14, in particular a granular classes selected from the group consisting of the granular classes 2/4, 2/6, 4/6, 6/10, 10/14 and mixtures thereof.

12. The method according to claim 1, wherein said bituminous binder may comprise one or several polymers, and/or one or several acids, and/or one or several fluxing agents as an additional additive of bitumen and/or of bitumen emulsion.

13. A cold-process bituminous coating composition comprising a bituminous binder initially as a cationic emulsion of bitumen and an aggregate, characterized in that said aggregate is an aggregate coated with lime.

14. The cold-process bituminous coating composition according to claim 13, wherein said lime is selected from the group consisting of calcium hydrated limes, dolomitic hydrated limes, hydrated magnesias, calcium-magnesium hydrated limes, quick calcium. limes, magnesia, calcium-magnesium or dolomitic quick limes, quick limes with retarded reactivity, including partly pre-hydrated limes, over-baked quick limes, partly slaked limes with exogenous additives and mixtures thereof, filter dusts, flying ashes including calcium ashes, Portland cements, hydraulic limes, construction limes as defined in the EN 459-1 standard, and mixtures thereof.

15. The cold-process bituminous coating composition according to claim 1, comprising a lime content from 0.05 to 2% by weight expressed as a hydroxide equivalent (Ca(OH).sub.2 and/or Mg(OH).sub.2) based on the total weight of aggregate.

16. The cold-process bituminous coating composition according to claim 13, wherein said aggregate is selected from the group consisting of gravels, sands and fillers, artificial aggregates including aggregates from deconstruction, special aggregates, aggregates of by-products from other industries and mixtures thereof.

17. The cold-process bituminous coating composition according to claim 13, wherein said aggregate belongs to a granular class d/D expressed in terms lower d and greater D sieve dimensions from 0/4 to 0/30, in particular a granular class selected from the group consisting of the granular classes of 0/4, 0/6, 0/8, 0/10, 0/14, 0/20, 0/30 and mixtures thereof.

18. The cold-process bituminous coating composition according to claim 13, wherein said aggregate belongs to a granular class d/D expressed in terms of lower d and greater D sieve dimensions from 2/4 to 10/14, in particular a granular class selected from the group consisting of the granular classes 2/4, 2/6, 4/6, 6/10, 10/14 and mixtures thereof.

19. The cold-process bituminous coating composition according to claim 13, wherein said binder may comprise one or several polymers, and/or one or several acids, and/or one or several fluxing agents as an additional additive of the bitumen and/or the bitumen emulsion.

20. The cold-process bituminous coating composition according to claim 13, further comprising a conventional additive to a bitumen emulsion, including a cationic surfactant containing nitrogen-containing functional groups, said functional groups being selected from the consisting of amines, imidazolines, amidoamines.

21. The cold-process bituminous coating composition according to claim 13, having a cohesion measured after 30 mins of ripening at room temperature by a Vialit plate test according to the EN 12272-3 standard characterized by a content of detached aggregates of less than 85/100 aggregates.

22. (canceled)

23. The cold-process bituminous coating composition according to claim 13, having a retained resistance measured according to the NIT-162 standard greater than or equal to 50%.

24. The cold-process bituminous coating composition according to claim 13, in the form of a cold-process bitumen composition, selected from the group consisting of a composition of cold dense bitumens, a composition of grave-emulsions or a composition of emulsion re-treatment.

25-26. (canceled)

Description

EXAMPLES

[0129] For the examples below, a bitumen emulsion called EMB1 with rapid breakage for forming a cold-process bituminous coating in the following way:

[0130] A bitumen emulsion EMB1 was manufactured by mixing the following ingredients in a laboratory plot equipped with a colloidal mill:

[0131] 66 parts by mass of bitumen 1601220 at a temperature of 140 C., stemming from the Repsol refinery of Puertoliana (Spain).

[0132] 34 parts of an aqueous phase at a temperature of 40 C., consisting of water, of 0.16 portions of tallow diamine (Asfier 100 provided by Kao) and of a supplement of hydrochloric acid giving the possibility of adjusting the pH to a value of 2.2.

[0133] An emulsion with 66% of binder EMB1 having a breakage index of 88 according to the EN 13075-1 standard is thereby obtained which corresponds to an emulsion of the type C6584 according to the EN 13808 standard. This type of emulsion is currently used for WSDs and is known as an emulsion with rapid breakage in the business.

Comparative Example 1

Manufacturing of a WSD (EC1)

[0134] A WSD (EC1) was made in the laboratory or within the scope of a Vialit plate test according to the EN 12272-3 standard. This is completely accomplished by applying the emulsion EMB1 in an amount of 1 kg/m.sup.2 of residual binder on a normalized metal plate of 2020 cm.sup.2. 100 silica-calcium aggregates G1 of caliber 6/10 stemming from the gravel pit of Jarama (Madrid, Spain) are regularly positioned at the surface of the freshly spread emulsion. After a ripening time of 30 minutes at room temperature, the WSD is subject to the test: The plate is turned over (aggregates oriented on the ground side) and a normalized steel ball of 510 g is released on the plate 3 times in succession from a height of 50 cm. At the end of the impacts, the aggregates which have detached from the plates are counted by separating clean aggregates and stained aggregates (i.e. the aggregates on which the binder adheres). The number of aggregates remaining stuck is thus evaluated as well as those fallen but clean or stained. The aggregates which remain stuck correspond both to good adhesiveness and good cohesion. The aggregates fallen and clean correspond to poor adhesiveness. The aggregates fallen, stained correspond to poor cohesion but to good adhesiveness. The given results are obtained as an average of 3 repetitions.

[0135] The results on WSD (EC1) as a reference are resumed in Table 1. Thus, after 30 minutes, it appears that quasi all the aggregates (96) have been detached from the plate following the impact and they all stained. This therefore indicates insufficient cohesion of the WSD after 30 minutes,

Example 1

Manufacturing of WSD Coatings (E1) According to the Invention.

[0136] The WSD (E1) according to the invention was made in the laboratory. To do this, the same test (Vialit) as for WSD (EC1) as a reference was used. The same emulsion EMB1 was applied in an amount of 1 kgirn.sup.2 of residual binder. The same aggregate G1 from the gravel pit of Jararna was also used, but it was treated beforehand this time with 0.25% by mass of concentrated lime milk stabilized at 45% by mass of hydrated lime (provided by Lhoist). This represents a supply of 0.11% of hydrated lime relatively to the aggregate. The aggregates were then positioned regularly at the surface of the freshly spread emulsion like for the WSD (EC1), thereby forming WSD (E1). After 30 minutes of ripening, the WSD is subject to the test.

[0137] The results on WSD (E1) according to the invention are again taken up in Table 1. It appears that a larger amount of aggregates (15) now remains stuck to the plate in spite of the impacts. This therefore indicates a clearly improved cohesion as compared with WSD (EC1) after 30 minutes, by means of the prior treatment of the aggregate with lime.

Example 2

Manufacturing of WSD Coatings (E2) According to the Invention.

[0138] The WSD (E2) according to the invention was made in the laboratory. To do this, the same test (Vialit) as for the WSD (EC1) as a reference was used. The same EMB1 emulsion was applied in an amount of 1 kg/n.sup.2 of residual binder. The same aggregate G1 stemming from the Jarama gravel pit was also used, but it was treated beforehand this time with 0.5% by mass of concentrated lime milk stabilized to 45% by mass of hydrated lime (provided by Lhoist).

[0139] This represents a supply of 0.23% of hydrated lime relatively to the aggregate. The aggregates were then positioned regularly at the surface of the freshly spread emulsion like for WSD (EC1), thereby forming WSD (E2). After 30 minutes of ripening, the WSD is subject to the test.

[0140] The results on WSD (E2) according to the invention are taken up again in Table 1. It appears that a larger amount of aggregates (21) now remain stuck to the plate in spite of the impacts. This therefore indicates a clearly improved cohesion relatively to WSD (EC1) after 30 minutes, by means of the preliminary treatment of the aggregate with iime.

Example 3

Manufacturing of WSD (E3) According to the Invention.

[0141] The WSD (E3) according to the invention was made in the laboratory. In order to do this, the same test (Vialit) as for WSD (EC1) as a reference was used. The same EMB1 emulsion was applied in an amount of 1 kg/m.sup.2 of residual binder. The same aggregate (31 stemming from the Jarama gravel pit was also used, but this time it was treated with 1% by mass of concentrated lime milk stabilized to 45% by mass of hydrated lime (provided by Lhoist). This represents a supply of 0.45% of hydrated lime relatively to the aggregate. The aggregates were then positioned regularly at the surface of the freshly spread emulsion like for WSD (EC1), thereby forming WSD (E3). After 30 minutes of ripening, the WSD is subject to the test.

[0142] The results on WSD (E3) according to the invention are again taken up in Table 1. It appears that a larger amount of aggregates (14) now remain stuck to the plate in spite of the impacts. This therefore indicates clearly improved cohesion relatively to the WSD (EC1) after 30 minutes, by means of the prior treatment of the aggregate with lime.

Comparative example 2

Manufacturing of the WSD Coating (EC2).

[0143] A WSD (EC2) was made in the laboratory according to the prior art. To do this, the same test (Vialit) as for the reference WSD (EC1) was used. This is accomplished by applying the same EMB1 in an amount of 1 kg/m.sup.2 of residual binder. Next, the spread emulsion was treated with 3% of a diluted lime milk, obtained by mixing 1 volume of industrial stabilized lime milk with 10 volumes of water. It should be noted that the amount of total hydrated lime represents about one quarter of the one used for the WSD (E2). A larger amount causes a breakage at the surface of the emulsion (skin), which does not give the possibility of properly embedding the aggregates. The aggregates G1 were then positioned regularly at the surface of the freshly spread emulsion. After 30 minutes of ripening, the WSD is subject to the test.

[0144] The results on the WSD (EC2) are again taken up in Table 1. It appears that after 30 minutes all the aggregates are detached. 7 detached aggregates are found to be clean, showing that the contact with the emulsion was perturbed by the direct supply of lime and the formation of a skin surface of the WSD, which prevents good contact with the aggregate. Also, it appears that the surface aspect is very poor, with certain aggregates mixed in the bitumen skin and a non-broken residual emulsion portion. Even if they had been able to remain stuck to the plate under the conditions of the test, it is clear that the passage of traffic would have generated immediate run of the WSD. Also, the presence of clean detached aggregates shows that the risk of detachment and therefore of windshield breakages, is very significant with this formula. Also, the results are clearly inferior to those obtained for the reference WSD (EC1).

TABLE-US-00001 TABLE 1 WSD WSD WSD WSD WSD WSDexamples (EC1) (E1) (E2) (E3) (EC2) Emulsion EMB1 EMB1 EMB1 EMB1 EMB1 Aggregate G1 G1 G1 G1 G1 Treatment (in % of hydrated 0 0.11% 0.23% 0.45% 0.12% lime relatively to the aggregate) Adherent aggregates (after 4 15 21 14 0 30 minutes) Clean detached aggregates 0 0 0 0 7 (after 30 minutes) Stained detached 96 85 79 86 93 aggregates (after 30 minutes)

Comparative example 3

Manufacturing of a Reference WSD (EC3).

[0145] A WSD (EC3) was made in the laboratory within the scope of a test with the Viailt plate by applying the EMB1 in an amount of 1 kg/m.sup.2 of residual binder on a normalized metal plate of 2020 cm.sup.2. 100 mylonitic aggregates G2 of calibre 6/10 stemming from the Almonacid gravel pit in Toledo (Castilla La Mancha, Spain) are regularly positioned at the surface of the freshly spread emulsion. After a ripening time of 30 mins at room temperature, the WSD is subject to the test in the same way as described earlier.

[0146] The results on the reference WSD (EC3) are again taken up in Table 2. Thus, after 30 mins, it appears that all the aggregates (100) have been detached from the plate subsequently to the impact and that they are all stained. This therefore indicates insufficient cohesion of the WSD after 30 rains.

Examples 4 to 6

Manufacturing of WSD Coatings (E4, E5, E6)

[0147] WSD coatings (E4, E5, E6) were made in the laboratory according to the invention. To do this, the same test (Vialit) as for the reference WSD (EC3) was used. This was done by applying the same EMB1 emulsion in an amount of 1 kgim.sup.2 of residual binder. The same aggregate 32 was also used, but it was treated beforehand with 0.25, 0.5 or 1% by mass of industrial concentrated lime milk stabilized to 45% by mass of hydrated lime, provided by Lhoist. This respectively represents a supply of 0.11%, 0.23% and 0.45% of hydrated lime relatively to the aggregate. The aggregates were then regularly positioned at the surface of the freshly spread emulsion like for WSD (EC3), thereby forming the WSDs (E4, E5, E6) respectively. After 30 mins of ripening, the WSD is subject to the test.

[0148] The results on the WSDs (E4, E5, E6) according to the invention are again taken up in Table 2. It appears that a larger amount of aggregates (2, 11 and 7 respectively) remains now stuck to the plate in spite of the impacts. This therefore indicates a clearly improved cohesion relatively to the WSD (EC3) after 30 mins, by means of the prior treatment of the aggregate with lime.

TABLE-US-00002 TABLE 2 WSD WSD WSD WSD WSDexamples (EC3) (E4) (E5) (E6) Emulsion EMB1 EMB1 EMB1 EMB1 Aggregate G1 G1 G1 G1 Treatment (in % of 0 0.11% 0.23% 0.45% hydrated lime relatively to the aggregate) Adherent aggregates 0 2 11 7 (after 30 minutes) Clean detached 0 0 0 0 aggregates (after 30 minutes) Stained detached 100 98 89 93 aggregates (after 30 minutes)

Example 7

Manufacturing of a Bitumen Emulsion EMB2 with Rapid Breakage.

[0149] A bitumen emulsion EMB2 was manufactured by mixing the following ingredients in a laboratory pilot installation equipped with a colloidal mill:

[0150] 66 parts by mass of bitumen 160/220 at a temperature of 140 C., stemming from the Repsol refinery of Puertollano (Spain).

[0151] 34 parts of an aqueous phase at a temperature of 40 C., consisting of water, of 0.2 portions of tallol fatty amides (indulin R66 provided by MeadWestVaco) and a supplement of hydrochloric acid giving the possibility of adjusting the pH to a value of 2.5.

[0152] An emulsion with 66% of binder EMB2 is thereby obtained with a breakage index of 90 according to the EN 13075-1 standard which corresponds to an emulsion of the C65B4 type according to the EN 13808 standard. This type of emulsion is currently used for WSDs and is known as an emulsion with rapid breakage in the profession.

Comparative Example 4

Manufacturing of a Reference WSD (EC4)

[0153] A WSD (EC4) was made in the laboratory within the scope of a Vialit plate test by applying the EMB2 emulsion of Example 7 in an amount of 1 kg/m.sup.2 of residual binder on a normalized metal plate of 2020 cm.sup.2. 100 aggregates G1 stemming from the Jarama gravel pit are regularly positioned at the surface of the freshly spread emulsion. After a ripening time of 30 mins at room temperature, the WSD is subject to the test in the same way as described earlier.

[0154] The results on the reference WSD (EC4) are again taken up in Table 3. Thus, after 30 mins, it appears that many aggregates (85) are detached from the plate subsequently to the impact and they are all stained. This therefore indicates low cohesion of the WSD after 30 mins.

Example 8 to 10

Manufacturing of the WSD coatings (E8, E9, E10).

[0155] WSD coatings (E8, E9, E10) were made in the laboratory according to the invention. For this, the same test (Vialit) as for the reference WSD (EC4) was used. This was done by applying the same emulsion EMB2 according to Example 7 in an amount of I kg/m.sup.2 of residual binder. The same aggregate G1 was also used, but it had been treated beforehand with 0.25. 0.5 or 1% by mass of industrial concentrated lime milk stabilized at 45% by mass of hydrated lime, provided by Lhoist. This respectively represents a supply of 0.11%, 0.23% and 0.45% of hydrated lime relatively to the aggregate. The aggregates were then positioned regularly at the surface of the freshly spread emulsion like for the WSD (EC4) thus making up the WSDs (E8, E9, E10) respectively. After 30 mins of ripening, the WSD is subject to the test.

[0156] The results on the WSDs (E8, E9, E20) according to the invention are again taken up in Table 3. It appears that a larger amount of aggregates (32, 46 and 43 respectively) now remains stuck to the plate in spite of the impacts.

[0157] This therefore indicates that a clearly improved cohesion relatively to the WSD (EC4) after 30 mins, by means of the prior treatment of the aggregate with lime.

TABLE-US-00003 TABLE 3 WSD WSD WSD WSD WSDexamples (EC4) (E8) (E9) (E10) Emulsion EMB2 EMB2 EMB2 EMB2 Aggregate G1 G1 G1 G1 Treatment (in % of hydrated 0 0.11% 0.23% 0.45% lime relatively to the aggregate) Adherent aggregates (after 15 32 46 43 30 minutes) Clean detached aggregates 0 0 0 0 (after 30 minutes) Stained detached 85 68 54 57 aggregates (after 30 minutes)

Comparative Example 5

Manufacturing of a Reference WSD (EC5)

[0158] A WSD (EC5) was made in the laboratory within the scope of a Vialit plate test by applying the EMB2 emulsion according to Example 7 in an amount of 1 kg/m.sup.2 of residual binder on a normalized metal plate of 2020 cm.sup.2. 100 mylonitic aggregates G2 of caliber 0/10 stemming from the Almonacid gravel pit in Toledo (Castilla La Mancha, Spain) are regularly positioned at the surface of the freshly spread emulsion. After a ripening time of 30 mins at room temperature, the WSD is subject to the test in the same way as described earlier.

[0159] The results on the WSD (ECS) are again taken up in Table 4. Thus, after 30 mins, it appears that nearly all the aggregates (99) are detached from the plate subsequent to the impact and that they are all stained. This therefore indicates insufficient cohesion of the WSD after 30 mins.

Example 11 to 13

Manufacturing of the WSD coatings (E11, E12, E13).

[0160] WSD coatings (E11 , E12, E13) were made in the laboratory according to the invention. To do this, the same test (Vialit) as for the reference WSD (ECS) was used. This is accomplished by applying the same EMB2 emulsion according to Example 7 in an amount of 1 kg/m.sup.2 of residual binder. The same aggregate SG2 was also used, but it had been treated beforehand with 0.25, 0.5 or 1% by mass of an industrial concentrated lime milk stabilized to 45% by mass of hydrated lime, provided by Lhoist. This respectively represents a supply of 0.11%, 0.23% and 0.45% of hydrated lime relatively to the aggregate. The aggregates were then positioned regularly at the surface of the freshly spread emulsion like for the WSD (EC5) thereby making up the WSDs (E11, E12, E13) respectively. After 30 mires of ripening, the WSD is subject to the test.

[0161] The results on the WSDs (E11, E12, E13) according to the invention are again taken up in Table 5. It appears that a larger amount of aggregates (23, 36 and 26 respectively) now remains stuck to the plate in spite of the impacts. This therefore indicates a clearly improved cohesion relatively to the WSD (EC5) after 30 mins, by means of the prior treatment of the aggregate with lime.

TABLE-US-00004 TABLE 4 WSD WSD WSD WSD WSDexamples (EC5) (E11) (E12) (E13) Emulsion EMB2 EMB2 EMB2 EMB2 Aggregate G2 G2 G2 G2 Treatment (in % of hydrated 0 0.11% 0.23% 0.45% lime relatively to the aggregate) Adherent aggregates (after 1 23 36 26 30 minutes) Clean detached aggregates 0 0 0 0 (after 30 minutes) Stained detached 99 77 64 74 aggregates (after 30 minutes)

Examples 14 and 15

Manufacturing of WSD Coatings (E14, 15).

[0162] WSDs (E14, E15) were manufactured as earlier, by using the WSD formulae (E5 and E12) respectively, but this time by letting the aggregate treated with lime mlik for 24 hours before its use in the WSD. The results are given in the following Table 5, wherein it appears that the beneficial effect of the treatment is obvious relatively to the VsiSD references (EC3) and (EC5) respectively (Tables 2 and 4).

TABLE-US-00005 TABLE 5 WSD WSD WSD examples (E11) (E12) Emulsion EMB2 EMB2 Aggregate G2 G2 Treatment (in % of hydrated 0.93% 0.23% lime relatively to the aggregate) Adherent aggregates (after 12 29 30 minutes) Clean detached aggregates 0 0 (after 30 minutes) Stained detached 88 71 aggregates (after 30 minutes)

Example 16

Manufacturing of a Bitumen Emulsion EMB3 with Slow Breakage.

[0163] A bitumen emulsion EMB3 was manufactured by mixing the following ingredients in a laboratory pilot installation equipped with a colloidal mill:

[0164] 60 parts by mass of bitumen 70/100 at a temperature of 140 C., stemming from the Repsol refinery of Puertollano (Spain),

[0165] 40 parts of an aqueous phase at a temperature of 40 C., consisting of 0.6 parts (based on the emulsion) of ethoxylated diamine channel (Asfier 218 provided by Kao) and a supplement of hydrochloric acid allowing adjustment of the pH to a value of 2.5.

[0166] An emulsion with 60% of EMB3 binder is thereby obtained with a breakage index of 260 according to the EN 13075-1 standard which corresponds to an emulsion of the C80B6 type according to the EN 13808 standard. This type of emulsion is currently used for cold bitumens and is known as an emulsion with slow breakage in the profession,

Comparative Example 6

Manufacturing of a Reference Grave-Emulsion GE1 (EC6).

[0167] A GE 1 (EC6) was made in laboratory. To do this, a aggregate G3 of grain size 0/25 from the Jarama gravel pit was used. This aggregate, with its natural humidity of 2%, was coated with 6% of the EMB3 emulsion according to Example 16 in order to finally obtain a bitumen content of 3.6%, and a supplement of 3.5% of water. The thereby obtained material was then compacted into cylindrical molds according to the Spanish NLT-161 standard. The specimens of GE 1 (ECG) thereby obtained were weighed for determining the density thereof and next conditioned according to the Spanish standard NLT-162 in order to measure the dry resistance and the resistance after an immersion of 24 hours in a bath at 60 C. The ratio of the resistances after immersion and under dry conditions, called the retain resistance, is then calculated. Depending on the targeted traffic, a value greater than 50, 60 or 75% is required in Spain for GEs. The GE 1 (EC6) obtains a value of 63% making it acceptable for a maximum traffic of 200 trucks/day (truck/j).

Example 17 and 18

Manufacturing of a Grave-Emulsion GE 2 (E17) AND GE 3 (E18)

[0168] GE 2 (E17) and GE 3 (E18) were manufactured according to the invention by using a recipe similar to that of GE 1 (EC6), with however a preliminary treatment of the aggregate G3 with 0.5 or 1% by mass of industrial concentrated lime milk stabilized at 45% by mass of hydrated lime, provided by Lhoist. This respectively represents a supply of 0.23% and 0.45% of hydrated lime relatively to the aggregate. The GE 2 and 3 were prepared according to the same steps of kneading and then compacting, and subject to the water resistance test (NLT-162). The results on the GE 2 and 3 according to the invention are taken up again in Table 6, It appears that the dry resistance and the retained resistance increase in a highly significant way by means of the treatment according to the invention, to the point that the specimens of GE 3 (E18) after immersion, however generating a damage, have a resistance greater than that under dry conditions of the reference GE 1 (ECG)l Also, GE 2 (E17) and GE 3 (E18) pass the most severe specification of retained resistance (75%). Unlike reference GE1 (EC6), they would thus be acceptable for a traffic of 800 trucks/d.

TABLE-US-00006 TABLE 6 GE GE GE GEexamples (EC6) (E17) (E18) Emulsion EMB3 EMB3 EMB3 Aggregate G3 G3 G3 Treatment (in % of hydrated lime relatively to 0 0.23% 0.45% the aggregate) Density (g/cm.sup.3) water resistance test (NLT-162) 2.393 2.386 2.388 Dry resistance (Mpa) 1.77 2.11 2.23 Resistance after immersion (MPa) 1.11 1.62 1.91 Retained resistance (%) 63 77 86

Example 19

Manufacturing of WSD Coatings (E19) According to the Invention.

[0169] The WSD (E19) according to the invention was made in the laboratory. In order to do this, the same test (Vialit) as for the reference WSD (EC1) was used. The same emulsion EMB1 was applied in an amount of 1 kg/rn.sup.2 of residual binder. The same aggregate G1 stemming from the Jarama gravel pit was also usedbut it had been treated beforehand this time with 0.2% by mass of quick lime (provided by Lhoist), in other words with 0.26% of lime expressed as a hydroxide equivalent. It should be noted that the aggregate had a water content of the order of 0.1 ,/o before treatment, and that the hydration reaction is therefore only partial before being put in contact with the emulsion, which will provide the supplement of water for completing the hydration. The aggregates were then positioned regularly at the surface of the freshly spread emulsion like for the WSD (EC1), thereby forming the WSD (E19). After 30 minutes of ripening, the WSD is subject to the test.

[0170] The results on the WSD (E19) according to the invention are taken up again in Table 7. It appears that a larger amount of aggregates (20) now remains stuck to the plate in spite of the impacts. This therefore indicates a clearly improved cohesion as compared with WSD (EC1) after 30 minutes, by the treatment beforehand of the aggregate with lime.

TABLE-US-00007 TABLE 7 WSD WSDexamples (E19) Emulsion EMB1 Aggregate G1 Treatment (in % of hydrated lime relatively to the 0.26% aggregate) Adherent aggregates (after 30 minutes) 20 Clean detached aggregates (after 30 minutes) 0 Stained setached aggregates (after 30 minutes) 80

Comparative Example 7

Manufacturing of WSD Coatings (EC7)

[0171] A WSD (EC7) was produced in the laboratory. To do this, the same test (Vialit) as for the reference WSD (EC1) was used. The same emulsion EMB1 was applied in an amount of 1 kg/m.sup.2 of residual binder. The same aggregate GI from the Jarama gravel pit was also used, but it was treated beforehand this time with 6% by mass of lime milk (provided by Lhoist), in other words with 2.7% of lime expressed as a hydroxide equivalent. The aggregates were then positioned regularly at the surface of the freshly spread emulsion like for the WSD (EC1), thereby forming the WSD (EC7). The WSD manufactured in this way generates a heterogeneous breakage of the emulsion with formation of the skin under the aggregates and confinement of water, which does not give the possibility of measuring the cohesion thereof after 30 mins. This formula is therefore not applicable on a roadway.

[0172] It is well understood that the present invention is by no means limited to the embodiments described above and that many modifications may be made thereto without departing from the scope of the appended claims.