FR2725196A1 - Concrete mixt. for roads and floors - Google Patents

Abstract

A composite concrete mixt. consists of a hard core, a hydraulic binder, a hydrocarbon binder, water and one or more additives. The vol. amt. of binder present is greater than 12% w.r.t. the amt. of hard core.

Description

 The invention relates to a composite concrete for constituting a surface or base layer of a road pavement, urban, agricultural or industrial or industrial soil, and a method for obtaining such a composite concrete.

 Roadway means here all types of traffic areas such as roads, streets, airfields, storage areas and handling, docks, etc.

 Composite concretes, also called mixed concretes, comprise at the same time a hydraulic binder, for example cement, and a hydrocarbon binder, for example bitumen. They are mainly intended for the realization of pavements, but can also be used for the production of molded objects constituting road accessories or parts to be integrated into an industrial floor.

Traditionally road construction materials for the pavement body belong to three major families depending on whether they are:
- unbound aggregates
granules bound with a hydraulic binder such as cement, slag, etc.

 aggregates bound with a hydrocarbon binder such as bitumen, bitumen emulsion, tar, etc.

 For each of the two last categories of materials, two main levels of mechanical qualities of use of these materials can be distinguished according to whether they are to be used as a structural layer (base layer, foundation layer) or as a tie layer or surface, that is to say in the part of the road where the mechanical aggressiveness of the traffic is maximum.

 The materials for the structural layers contain sufficient amounts of binder to provide the assembly with sufficient elastic modulus and tensile strength to withstand the stresses induced by the traffic.

The amount of binder introduced into the granular material is then quite low, ie of the order of 3.5 to 4.5% of the total mass for a bituminous mixture, then called severe bitumen or serious emulsion according to the method of introduction of the bitumen. In the case of a cement-based bond the binder content is also of the order of 3.5 to 4.5%, so-called high-cement. (The values quoted are for conventional granular and "serious" type materials)
Materials intended for surface or bonding layers, but which may nevertheless be used as a structural layer in some cases, must have improved mechanical characteristics compared to structural layer materials. In fact, the surface layers are subjected to much larger localized forces under the effect of the aggressiveness of the traffic. In addition, these layers must withstand the direct aggression of bad weather and possible accidents. For these reasons, the binder content of the surface materials is substantially higher than that of the structural materials. This is called bituminous concrete with bitumen contents of the order of 6% bitumen or cement concrete with cement contents of the order of 350 kg of cement per m3 of concrete. A quick calculation shows that the amount of binder in relation to the quantity of aggregates, expressed this time in volume, is about 16% for asphalt concrete and about 18% for cement concrete. These two figures are quite comparable and show that a minimum volume of binder is required to fill a surface material.

 On the other hand, there is a significant difference between cement concrete and all the other materials mentioned: while the latter have good lift at the time of implementation, which also allows their adjustment with traditional means of public works, such as grader or compactor with compactors with pneumatic tires or with smooth rims, vibrating or not, cement concrete has no bearing capacity when it is put in place and must be applied by conventional or sliding formwork and compacted by vibration without rolling and for example with vibrating needles or a vibrating rule. Such a coating becomes circulable only after a set time, on the other hand it can be applied on a mediocre support medium.

 The main disadvantage of cement concrete is that it exhibits catch cracking and unavoidable thermal shrinkage. The cracks appear naturally spaced about 5 m in all directions. The position of the cracks can be controlled by making joints defining square or rectangular cement concrete slabs having a side of the order of 5 m. But it is necessary to fill these joints to seal and maintain them regularly. In addition, this type of structure is uncomfortable and noisy. These disadvantages can be limited by the use of metal reinforcements in the mass of cement concrete. However, these frames are expensive, have no structural effect, and the cracks remain although they are then thinner and closer and therefore less troublesome.

 Granular materials have already been treated with a composite binder containing a hydrocarbon binder and a hydraulic binder. For example, a composite binder for road surfacing described in document FR-2,661,173 and known under the name STABICOL (registered trademark) is known.

 However, the binder content with respect to the dry aggregates remained in the range of the contents by binding structure layer materials, never exceeding 10% by volume. In particular, such rates resulted in water contents of the mixture such that the consistency of the material in the implementation made it usable with usual public works machinery such as grader or paver. Such materials are satisfactory in their use as a structural layer but do not contain enough binder to be used as a surface layer.

 It has already been tried to produce mixed concrete. However, it has proved necessary to introduce hydraulic and hydrocarbon binders separately. The separate and sequential introduction of these two binders into the same kneader makes it difficult to control any proportions of the two binders (bitumen cement ratio) in the range proposed by the present invention, for questions of precision of the assay with the existing controls . In addition, the dispersion of the two binders separately can not result in a perfectly homogeneous mixture. In addition, the test sites made with such a technique have quickly exhibited cracking identical to that of a conventional cement concrete.

 The object of the invention is to overcome the disadvantages described above.

 More particularly, the invention must provide a concrete whose cracking can be limited or even avoided, without it being necessary to provide the concrete slab to obtain a metal reinforcement.

 The object of the invention is also to provide a material that allows its application as a surface layer.

 The invention relates to a composite concrete intended to form a surface layer or base of a road pavement, urban, agricultural or industrial or industrial soil. This composite concrete comprises aggregates, a hydraulic binder and a hydrocarbon binder and any additives.

 According to the invention, the relative proportion by volume of all the hydraulic and hydrocarbon binders, with respect to aggregates, of this concrete is greater than 12%.

 This proportion is preferably between 14% and 18%.

 The invention makes it possible to limit cracking without using armatures which are expensive and difficult to implement.

 The invention involves the use of a composite binder consisting of a bituminous emulsion and a hydraulic binder.

 The composite concrete of the invention is a material for surface layer as described above but with a composite binder based on an emulsified hydrocarbon binder associated with a hydraulic binder in aqueous phase in homogeneous and stable suspension. The manufacture and the implementation of the mixed concrete are carried out cold (ambient temperature).

 The composite binder may, for example, be that described in FR-2,661,173 and called Stabicol (registered trademark).

 An important feature of the mixed concrete of the invention is that its consistency at the time of implementation does not allow its use with conventional public works materials but that its consistency is very close to that of a cement concrete and that therefore it must be implemented with similar means. This consistency is due to the amount of water required both to convey the binders and the setting of the hydraulic binder.

 Achieving such a mixture with acceptable workability and performance has been made possible by searching for formulations resulting in the present invention.

Indeed, the known hydraulic concrete formulations generally result in a mixture too liquid when they are used with a composite binder as described above, they are poor in implementation and poor performance. In addition, only a particularly suitable bitumen emulsion may be suitable. Conventional bitumen emulsions fail in the presence of cement, which makes mixing impossible. In particular, it has been brought about to reduce the amount of filler water conventionally used in the preparation of the composite binder, including the bituminous emulsion and the hydraulic binder. The use of additives such as silica fume and superplasticizer also improves the characteristics of the composite concrete. The use of an air-entraining additive included in the bitumen emulsion ensures an air content. occlusive important, to guarantee the frost content of the mixture.

 The invention thus makes it possible in particular to overcome the obstacles of feasibility and workability and to obtain high mechanical performance.

 The characteristics of the materials bonded with a mixed binder such as Stabicol (trademark) for example are interesting because such a binder confers a high elastic modulus, good tensile strength, excellent resistance to creep and rutting but also considerably limits the risk and the importance of the setting shrinkage cracking phenomenon of the hydraulic binder by which the previously stated qualities are obtained.

 It was therefore tempting to try to obtain a surface layer with such a binder since the characteristics that one could hope for would have made a good coating.

The composite concrete of the invention contains a portion of aggregates including crushed chippings completely, or partially or not, and whose maximum grain size may be 40 mm, 20 mm or 14 mm and sands from alluvium or crushing massive rocks. The binder consists of a hydraulic binder and an emulsion of bitumen which are incorporated already mixed in the mixer with the aggregates. The mixture also contains additive water to adjust the consistency and additives such as setting retarder, plasticizer, super plasticizer, air entrainer as needed for each particular case. Examples of additives are known as the following trade names: PLASTIRETARD of SIKA and CIMAXTARD 101 of AXIM, which are set retarders, and SIKAMENT 10 of the company
SIKA who is a superplasticizer.

 The proportions between sand and gravel are variable and depend on the final use of composite concrete.

The proportions between the hydraulic binder and the hydrocarbon binder can vary and are preferably within the range of 30 to 150 (ratio of the weight of residual bituminous binder to the weight of the dry hydraulic binder before hydration, multiplied by 100). The hydraulic binder is generally a standardized cement or foreign equivalents for the construction such as that known as CPJ-CEM II / A or B 32.5 produced by most cement manufacturers. It can also be chosen from the so-called "road" binders whose short-term performance is a little weaker but becomes excellent in the long term. The hydrocarbon binder is a road bitumen whose category can be adapted to each particular case. for example, to mention an emulsifiable 180/220 grade bitumen. It can also be modified by additives such as polymers or fibers. Finally, it can be a synthetic pigmentable bituminous binder, in particular for the purpose of producing a colored composite concrete. The hydrocarbon binder is emulsified in an aqueous phase prior to its use for the invention in a specialized plant. The bitumen emulsion required for the preparation of the composite concrete is then obtained. A suitable bitumen emulsion is, for example, the emulsion marketed by COLAS (registered trademark) under the name COLFOR (registered trademark) because it contains compatibilizing agents with most of the cements currently available in France and worldwide.

A ready-to-use binder already containing the cement and bitumen emulsion such as STABICOL (registered trademark) from the company COLAS (registered trademark) will be advantageously used. This binder can also contain predosed additives such as the air entrainer, the retarding agent, etc.

 The total amount of water in the mixture can vary from 2 to 15% of the weight of the dry aggregates.

The invention furthermore relates to applications of the mixed concrete defined above, namely:
- for the completion of a road surface, either
- for the production of industrial soil, either
- for the realization of a road accessory or industrial ground.

 The mixed concrete, or composite concrete of the invention, is mainly used for the production of layers of surfaces or road, airport or industrial bases or objects made using slipforms such as gutters, curbs or Nozzles or other road accessories usually made of cement concrete or asphalt.

 The invention also relates to a process for obtaining a composite concrete intended to form a surface or base layer of a road pavement, urban, agricultural or industrial or industrial soil, including aggregates, a hydraulic binder and a hydrocarbon binder.

According to the invention, this method comprises the steps of
a) - heating in a container a hydrocarbon binder to
a temperature between about 100 C and
200 C
b) - introduce in water having a temperature
between about 10-C and about 80 C an agent
surfactant
c) - mixing the surfactant with the hydrocarbon binder
to obtain an aqueous emulsion
d) - sending the aqueous emulsion into a homogenizer
while introducing into this homogenizer, so
separate, hydraulic binder
e) - mixing aggregates previously dosed with the
binder mixture previously manufactured in a
mixer, concrete mixer or concrete mixer.

Advantageously, the method defined above may also include one or more of the following characteristics in all the technically possible combinations:
an adjuvant intended to control the setting speed of the hydraulic binder is added;
the adjuvant is chosen from setting retarders, hardening accelerators, plasticizers, plasticizers, inhibitors, thixotropic agents and organic polymers;
the relative proportion of hydraulic binder with respect to the hydrocarbon binder is 100 parts of hydraulic binder for 30 to 300 parts of aqueous emulsion of hydrocarbon binder;
the hydrocarbon-based binder is chosen from pure bitumens, regeneration bitumens, paraffinic, naphthenic or aromatic petroleum solvents, petroleum compounds resulting from steam-cracked distillates, pure tars, coal-fluxing oils, heavy oils, soft and special pitches, synthetic bitumens;
the hydraulic binder is standard cement or activated slag cement or fly ash or a mixture of these different binders to which water is added if necessary.

 Finally, the subject of the invention is a kneading device for implementing the method for obtaining a mixed concrete, as defined above.

 Indeed, the mixed concrete can be manufactured manually in a concrete mixer or industrially in a facility called mixing plant. The mixing plant must allow precise dosing of each of the constituents mentioned above and their homogeneous mixture. This mixing plant can be of continuous or discontinuous type.

 The transport of such a material can be done in dump trucks if the distance and the time of transport are short or in trucks-router such as those used for the transport of cement concrete when the distance is greater. In some cases it is preferable to use such a truck mixer as a mixer to ensure the mixing of components after dosing in a central dosing.

 A manufacturing variant consists of using the same mixer for the preparation of the composite binder and composite concrete. In this case, the bitumen emulsion and the necessary water are introduced first and then the hydraulic binder is incorporated under mixing. The aggregates are finally incorporated when the composite binder is ready.

 The implementation is done either manually in a formwork, with compaction by ruler or vibrating needles, or with a slippery formwork machine ensuring the shaping and compacting by pervibration of the composite concrete, the formulation study must then make it possible to obtain the consistency adapted to such an implementation.

 It is an important part of the invention to have shown that such a mixture could be formulated so that its consistency is compatible with these different modes of implementation, for example using the standardized test NF P 18451 d. Abrams cone collapse and to obtain values less than 5 cm, but it is possible to adjust this property to another value depending on its use, by adding a larger quantity of water or water. 'additive. Another test highlighting the good consistency of composite concrete is the standardized NF P 18452 test at the Bridges and Roads Laboratory (LPC) handgun, where values between 15 and 25 seconds are obtained.

 The composite concrete of the invention has a higher elastic modulus in general at 15 000 MPa and frequently greater than 20 000 MPa depending on the constituents chosen which is much higher than that of an asphalt concrete, of the order of 5000 at 10,000 MPa. It has a good tensile strength since its tensile strength by splitting is at least greater than 0.5 MPa and is commonly about 1 MPa at a speed of 0.05 MPa / s. The compressive strength exceeds 5 MPa and easily reaches 10 MPa depending on the materials used.

 This product therefore ranks among the high-end materials for pavement construction. And it is quite interesting to be able to have such a material without it has the disadvantages inherent to bituminous mixes, ie rutting or creep, sensitivity to temperature. For example from the rutting test NF P 98-253-1 at 60 ° C, the rut measured is less than 1 mm after 100,000 cycles whereas under the same conditions this rut is greater than 10 mm for a concrete bituminous.

 A consequence of this resistance to permanent deformations is its very good resistance to the punching phenomenon since it withstands pressures under one point load of more than 20 MPa while a bituminous concrete withstands under the same conditions at best 1 MPa.

 Another advantage with respect to bituminous mixes is that it can, if necessary, be used on a carrier of poor quality of lift since compaction is not done by rolling with heavy machinery. Indeed the compaction by rolling requires a support of good immediate bearing to be effective, while the compaction by simple vibration can accommodate a mediocre support.

 It is also advantageous to have these qualities without having to suffer from the disadvantages inherent in the use of high dose cement as in cement concretes. One of these drawbacks is the shrinkage due to the setting of the hydraulic binder which generates a large cracking, which can only be avoided by sawing expansion joints and or incorporating metal reinforcements into the body of the cement concrete. Mixed composite concrete makes it possible to limit this phenomenon of cracking and thus to avoid making joints or laying reinforcements.

 Another aspect of the invention is that the composite concrete material is particularly resistant to chemical agents of all kinds. In particular, it is resistant to petroleum products, thanks to its cement-related matrix. A coating bonded to the composite binder will not lose its mechanical characteristics following an attack by a petroleum product, unlike bituminous mixes whose binder is fully soluble in these solvents, in particular gasoline, diesel etc., which can lead to the ruin of the structure in case of systematic attack.The composite concrete also resists most acids and bases. It is naturally resistant to water and because of its hydrophobic nature due to the presence of bitumen, the water infiltrates its voids less easily than in those of a cement concrete, which makes it less sensitive to water. gel. In addition, the composite concrete contains a significant amount of occluded air (more than 4%), which also ensures its frost resistance.

 Finally, it is possible to formulate a colored composite concrete using a pigmentable synthetic bitumen, such as Mexphalt C from Shell for the manufacture of the bituminous emulsion and by incorporating inorganic or organic pigments into the composite binder, either in aggregates. Such a coating provides a coating of high mechanical performance and aesthetic appearance, which can be incorporated into an architectural achievement.

 Because of its composition and the properties set out above, composite concrete has a relatively wide field of application. It can be used as a bonding or surface layer for any type of road that has to withstand heavy or aggressive traffic. This concerns in particular motorways, national roads, bus lanes, airport lanes and aerodromes, port areas, unloading docks and industrial floors, dairies, sugar factories, etc. This also concerns any pavement that would be to be made on a poor quality support or steep slope so that it would be difficult to compact traditional materials. An example of this type of application are steep farm tracks, particularly in some vineyards with hillsides.

 Considering the excellent mechanical characteristics of this material and its compacting mode, as well as its minimum thickness, its contribution to the pavement structure is important, so it can constitute by itself the base layer and the wearing course or the base layer and the tie layer if a specific wearing course is required. pavement design will therefore take into account the mechanical characteristics of the composite concrete and the traffic characteristics to be borne by the pavement to define the thickness of materials to be used.

This thickness may be between 5 and 25 cm, but preferably between 10 and 20 cm.

 When surface quality such as roughness, drainability or roughness must meet very specific criteria, it will be possible to use, as the case may be, for example, a very thin, ultra-thin bituminous concrete type asphalt layer. or draining to ensure these surface qualities. Composite concrete will then form the base and bonding layer of the structure. On the other hand, in the case of use in industrial soil where the qualities of mechanical and chemical resistance on the surface are essential, a coating of asphalt is contraindicated. Surface treatment such as surfacing, sanding, plasticizing, etc.

are possible for particular applications.

 The tables shown below show three embodiments of a mixed concrete according to the invention, as well as their characteristics measured in the laboratory.

The third example shows the possibility of using additives (superplasticizers, silica fume) in composite concrete.

EXAMPLE <SEP> 1: <SEP> EXAMPLE <SEP> 2
<tb> Granulats <SEP> dioritic <SEP> and <SEP> silico- <SEP> Aggregates <SEP> silico-limestone
<tb> limestone: <SEP> quarry <SEP> from <SEP> the <SEP> Aggregates <SEP> from <SEP> Courville <SEP> and
<tb> Meilleraie <SEP> and <SEP> Seine <SEP> and <SEP> Seine
<tb> Composition <SEP> of <SEP> mixture <SEP> in <SEP> 10/14 <SEP> Meilleraie: <SEP> 767 <SEP> 14/20 <SEP> Courville: <SEP> 410
<tb> kg / m3 <SEP> 6/10 <SEP> Meilleraie: <SEP> 427 <SEP> 6/14 <SEP> Courville: <SEP> 718
<tb> 0/2 <SEP> Meilleraie: <SEP> 174 <SEP> 0/4 <SEP> Courville: <SEP> 174
<tb> 0/5 <SEP> Seine: <SEP> 675 <SEP> 0/5 <SEP> Seine: <SEP> 608
<tb> Bitumen <SEP> 180/220: <SEP> 68 <SEP> Bitumen <SEP> 180/220: <SEP> 63
<tb> Cement <SEP> CPJ <SEP> 45: <SEP> 136 <SEP> Cement <SEP> CPD <SEP> 45: <SEP> 127
<tb> Water: <SEP> 102 <SEP> Water: <SEP> 102
<tb> Self-timer <SEP> of <SEP> taken * <SEP> 0.7 <SEP> Self-timer <SEP> of <SEP> taken * <SEP> 0.7
<tb> Emulsifier, <SEP> anti- <SEP> Emulsifier <SEP> antiflocculant ** <SEP> 6 <SEP> flocculant ** <SEP> 6
<tb> Total <SEP> voids <SEP> at <SEP> molding <SEP> 14% <SEP> 14%
<tb> Content <SEP> in <SEP> air <SEP> occluded <SEP> 8% <SEP> 7%
<tb> Maneuverability <SEP> LPC <SEP> 20 <SEP> seconds <SEP> 21 <SEP> seconds
<tb> Sag <SEP> at <SEP> cone <SEP> 2 <SEP> cm <SEP> 2 <SEP> cm
<tb> NF <SEP> P <SEP> 18-451
<tb> Resistance <SEP> Compression
<tb> 90 <SEP> days <SEP> 8.2 <SEP> MPa <SEP> 7.2 <SEP> MPa
<tb> 360 <SEP> days <SEP> 11 <SEP> MPa
<tb> NF <SEP> P <SEP> 98-2321
<tb> Module <SEP> in <SEP> Compression
<tb> 90 <SEP> days <SEP> 2500 <SEP> MPa <SEP> 2300 <SEP> MPa
<tb> 360 <SEP> days <SEP> 2600 <SEP> MPa
<tb> NF <SEP> P <SEP> 98-232-1
<Tb>

* Plastiretard ** SAPSTO5 from Ecoliant

EXAMPLE <SEP> 1: <SEP> EXAMPLE <SEP> 2
<tb> Granulats <SEP> dioritic <SEP> and <SEP> silico- <SEP> Aggregates <SEP> silico-limestone
<tb> limestone: <SEP> quarry <SEP> from <SEP> the <SEP> Aggregates <SEP> from <SEP> Courville <SEP> and
<tb> Meilleraie <SEP> and <SEP> Seine <SEP> and <SEP> Seine
<tb> Resistance <SEP> Slitting
<tb> 90 <SEP> days <SEP> 1.1 <SEP> MPa <SEP> 0.9 <SEP> MPa
<tb> 360 <SEP> days <SEP> 1,9 <SEP> MPa
<tb> NFP <SEP> 18-408
<tb><SEP> resistance to <SEP> punching
<tb> (5 <SEP> cm2 <SEP> - <SEP> 24 <SEP> hours
<tb> 20 C <SEP> 34 <SEP> MPa <SEP> 27 <SEP> MPa
<tb> 50 C <SEP> 27 <SEP> MPa <SEP> 21 <SEP> MPa
<tb> Rutting <SEP> to <SEP> 60 C <SEP> and
<tb> 100 <SEP> 000 <SEP> cycles <SEP> 0.3 <SEP> mm <SEP> 0.5 <SEP> mm
<tb> Cycles <SEP> NF <SEP> P <SEP> 98-253-1
<tb> Resistance <SEP> to <SEP><SEP> Compression <SEP>(<SEP> 28 <SEP> days <SEP> of <SEP> Take) <SEP> After <SEP> Immersion <SEP> 7 <SEP> days <SEP> in <SEP> the
<tb> Aggressive <SEP> Products <SEP> - <SEP><SEP><SEP> values are <SEP> expressed <SEP> in <SEP><SEP> residual <SEP> resistors by <SEP><SEP report > to
<tb> the <SEP> reference
<tb> Gas oil <SEP> 81% <SEP> 84%
<tb> Acid <SEP> HCl <SEP> 1 <SEP> mol / 1 <SEP> 90% <SEP> 100%
<tb> Base <SEP> NaOH <SEP> 0.1 <SEP> mol / 1 <SEP> 78% <SEP> 77%
<Tb>
EXAMPLE 3: COMPOSITE CONCRETE
CONSTANT PART
10/14 Meilleraie: 555 kg / m3
6/10 Meilleraie: 363 kg / m3
2/16 Meilleraie: 299 kg / m3
0/2 Meilleraie: 684 kg / m3
0/5 Seine: 235 kg / m3
Stabicol 50B composite binder: 289 kg / m3

<tb><SEP> PART <SEP> VARIANT
<tb> Superplasticizer <SEP> 0 <SEP> 2.1kg / m3 <SEP> 0 <SEP> 0
<tb> SIKAMENT <SEP> 10
<tb> Smokes <SEP> of <SEP> silica <SEP> 0 <SEP> 0 <SEP> 7.1 <SEP> kg / t <SEP> 14.3kg / t
<tb> Water <SEP> of addition <SEP> 75kg / m3 <SEP> 55kg / m3 <SEP> 55 <SEP> kg / m3 <SEP> 55kg / m3
<tb> Air <SEP> occluded <SEP> 8.1% <SEP> 6.7% <SEP> 6% <SEP> 6%
<tb> Rc <SEP> 28 <SEP> days
<tb> (MPa) <SEP> 5.0 <SEP> 5.7 <SEP> 7.2 <SEP> 7.9
<tb> Ec <SEP> 28 <SEP> days
<tb> (Mpa) <SEP> 20800 <SEP> 23000 <SEP> 25700 <SEP> 27000
<tb> RF <SEP> 28 <SEP> days
<tb> (MPa) <SEP> 0.72 <SEP> 0.90 <SEP> 1.0 <SEP> 1.2
<tb> Sagging
<tb> at <SEP> cone <SEP> (cm)
<tb> NP <SEP> P <SEP> 18-451 <SEP> 4 <SEP> 4 <SEP> 4 <SEP> 4
<Tb>

Claims (10)

 1. Composite concrete intended to constitute a surface or base layer of a road, urban, agricultural or industrial road surface or of industrial soil, comprising aggregates, a composite binder combining a hydraulic binder and a hydrocarbon binder, water, and one or more additives, characterized in that the relative proportion by volume of all the hydraulic and hydrocarbon binders relative to the aggregates is greater than 12%.  2. Composite concrete according to claim 1, characterized in that the relative proportion by volume of all the hydraulic and hydrocarbon binders, relative to the aggregates, is between 14% and 18%.  3. Composite concrete according to one of claims 1 and 2, characterized in that the hydrocarbon binder is a pigmentable synthetic bitumen and that the mixture contains one or more inorganic pigments, the concrete thus constituting a resistant colored coating.  4. Process for obtaining a composite concrete intended to form a surface or base layer of a road, urban, agricultural or industrial road surface or of an industrial ground, comprising aggregates, a hydraulic binder and a hydrocarbon binder characterized in that the method comprises the steps of  a) - heating in a container a binder  hydrocarbon at a temperature between  about 100 ° C and 200 ° C  b) - introduce in water having a temperature  between about 10 ° C and about 80 ° C  surfactant;  c) - mixing the surfactant with the binder  hydrocarbon to obtain an aqueous emulsion;  d) - send the aqueous emulsion in a  homogenizer while introducing into this  homogenizer, separately, a binder  hydraulic;;  e) - mix aggregates previously dosed with  the binder mixture previously manufactured in a  mixer, concrete mixer or concrete mixer.  5. Method according to claim 4, characterized in that the mixture of the aqueous emulsion of the hydraulic binder is made in the same mixer as the final mixture with the aggregates.  6. Method according to claim 4 or 5, characterized in that an adjuvant for controlling the setting speed of the hydraulic binder and the final performance of the composite concrete is added.  7. Method according to claim 6, characterized in that the adjuvant is chosen from setting retarders, curing accelerators, fluidifiers, plasticizers and superplasticizers, inhibitors, thixotropic agents and organic polymers, special fillers. , fumes of silicas.  8. Method according to any one of claims 4 to 7, characterized in that the relative proportion of hydraulic binder relative to the hydrocarbon binder is 100 parts of hydraulic binder for 30 to 300 parts of aqueous hydrocarbon binder emulsion.  9. Process according to any one of claims 4 to 8, characterized in that the hydrocarbon binder is selected from pure bitumens, regeneration bitumens, petroleum solvents paraffinic, naphthenic or aromatic, petroleum compounds resulting from steam cracked distillates. , pure tars, coal fluxing oils, heavy oils, soft and specialty pitches, synthetic bitumens.  10. Method according to one of claims 4 to 8, characterized in that the hydraulic binder is cement or activated slag cement.