EP0457667A1 - Method for constructing a waterproof bridge deck - Google Patents

Abstract

The waterproof complex is characterised in that it comprises:   - a lower layer of hot-coated material, consisting of an asphalt binder and an aggregate, the asphalt binder representing from approximately 8.5 to approximately 10.5 parts by weight per 100 parts by weight of aggregate,   - an intermediate layer consisting essentially of an asphalt binder,   - an upper layer of cold-cast coated product. <??>Such a waterproof complex has a high capacity for preventing the propagation of ascending or descending cracks.

Description

The present invention relates to a waterproofing structure for a road structure and a method for waterproofing a road structure apron.

Several techniques make it possible to seal road structures. Among these, mention may be made of the spreading of asphalt and the spreading of a thin film, for example of the epoxy pitch type, adhering to the concrete deck of the structure. The use of prefabricated membranes also makes it possible to produce a sealed device. These materials have fairly low yields in common. In addition, they are sensitive during their implementation to atmospheric variations.

Achieving the watertightness of a classic work of art, a bridge for example, using one of these techniques is relatively long to execute, and thus delays the commissioning of the work. In addition, these techniques do not always allow the use of conventional road equipment, such as spreaders, and use additional equipment as well as a large workforce.

• une couche inférieure d'enrobé à chaud constituée d'un mortier comportant environ 11 à environ 16% de granulat de diamètre inférieur à 80 µm et d'environ 8,5 à environ 10,5% d'un liant bitumeux à base d'élastomères, les pourcentages étant exprimés en poids par rapport au granulat sec,
• une couche intermédiaire constituée d'un bitume riche en élastomères.

A solution was provided by the invention described in French patent application No. 87 05435. It relates to a waterproofing complex for a road structure mainly intended to receive a wearing course, characterized in that it includes:

• a lower layer of hot mix consisting of a mortar comprising approximately 11 to approximately 16% of aggregate with a diameter of less than 80 μm and from approximately 8.5 to approximately 10.5% of a bituminous binder based on elastomers, the percentages being expressed by weight relative to the dry aggregate,
• an intermediate layer consisting of a bitumen rich in elastomers.

A disadvantage of this type of waterproofing complex is that, during the laying of the first hot mix carpet (constituting the wearing course) on the bituminous intermediate layer, even sanded, it melts and percolates from bottom to top at the base of this mat, so that its thickness decreases sharply until almost completely disappears if the temperature of the mix is excessive. The ability to avoiding the propagation of ascending or descending cracks is then considerably lessened, because an asphalt mat, even highly enriched with bituminous binder at its base, is obviously less deformable than a layer of pure binder.

The present invention aims to remedy this drawback and to improve the tightness of the complex of patent 87 05435, which is particularly useful for engineering structures subjected to significant thermal stresses, in particular for engineering structures in high mountains. .

• une couche inférieure d'enrobé à chaud comportant, pour 100 parties de granulat, d'environ 8,5 à environ 10,5% d'un liant bitumineux contenant des élastomères, environ 11 à environ 16% en poids du granulat ayant un diamètre inférieur à 80 µm.
• une couche intermédiaire constituée essentiellement par un liant bitumeux,
• une couche supérieure d'enrobé coulé à froid.

The waterproofing complex of road engineering structure according to the invention is characterized in that it comprises:

• a lower layer of hot mix comprising, per 100 parts of aggregate, from approximately 8.5 to approximately 10.5% of a bituminous binder containing elastomers, approximately 11 to approximately 16% by weight of the aggregate having a diameter less than 80 µm.
• an intermediate layer consisting essentially of a bituminous binder,
• an upper layer of cold-cast mix.

The upper layer of cold-cast mix consists of an emulsion bituminous binder and an aggregate, the maximum particle size of which remains less than approximately 10 mm.
For 100 parts by weight of aggregate, the cold-cast mix of the upper layer contains from about 6 to about 20 parts of residual binder.
The aggregate of the upper layer of cold-cast mix is preferably crushed sand. The upper layer of cold-poured asphalt constitutes a heat shield preventing any rise in the bituminous binder of the intermediate layer, in the first hot asphalt mat applied to the complex.
The upper layer of cold-poured asphalt can be in the form of a single-layer, or a two-layer. For a single layer, the aggregate is preferably a continuous crushed 0/6 or 0/10. For a two-layer, preferably a continuous sand 0/4 or 0/6, or a discontinuous sand 0/6.
When the top layer of cold poured asphalt forms the wearing course, preferably a discontinuous particle size 0/6 or 0/10, or a continuous particle size 0/10.
The thickness of the cold-cast mix layer is advantageously between 3 and 12 mm. It is essentially a function of the grain size of the sand. Thus, for a 0/2 sand, the thickness is of the order of 3 to 5 mm; for 0/4 sand, it is 5 to 7 mm; for 0/6 sand, it is 7 to 10 mm.
A filler can optionally complete the granulometry of the aggregates such as for example a ground rock powder, preferably limestone, cement, natural or artificial rock fibers, or even organic fibers. The filler content is less than 10% by weight relative to the aggregate. The bituminous binder of the upper layer of cold-cast mix contains essentially a bitumen. The bitumen can be chosen from pure bitumens, preferably from bitumens of grades 60/70 and 80/100. The bitumen used can also be a bitumen modified by the addition of thermoplastic copolymers, either by direct hot mixing of pure bitumen and of copolymers, or by indirect cold mixing of pure bitumen emulsion and of aqueous dispersion of copolymers at the time of manufacture of the asphalt to be poured. Preferably, ethylene vinyl acetate (EVA) or styrene butadiene styrene styrene (SBS) or ethylene methacrylate (EMA) copolymers will be used. However, it is also possible to use the styrene butadiene rubber block copolymers (SBR) and the acrylic copolymers as well as various mixtures of these copolymers. The copolymer content is at most equal to about 5% by weight. The addition of such copolymers has the effect of a less rejection on commissioning, a better binder-aggregate bond, increased brine resistance, a reduction in sensitivity to heat and cold, greater cohesion as well as '' better deformability.
In a variant of the invention, the bituminous binder of the upper layer of cold-cast mix also contains synthetic fibers. The fibers used are ultra-fine synthetic fibers (a few decitex) and relatively long (4 to 8 mm). They are chosen according to the elastic modulus of the material of which they are made, in order to obtain a fibrous mix whose deformability is compatible with that of the support on which it will be applied. Low modulus fibers will be used for the most deformable structures. The proportion of fibers is advantageously between 0.05 and 3% by weight. This proportion may be very low, but given the extreme fineness of these fibers, their number per square meter of asphalt poured is considerable, as well as the length of the network that they constitute. The addition of fibers to the bituminous binder is particularly desirable when this binder contains an aggregate whose particle size is discontinuous.

The aggregate of the lower layer of hot mix can consist, for example, of a mixture of crushed or ground sand of grain size 0-2, rolled sand of grain size 0-2 to 0-4, and crushed sand of grain size 2 -4. You can use a mortar with grain size 0-2 or a micro-gravel with grain size 0-6.
The bituminous binder used for the lower layer of hot mix can be chosen from the bituminous binders described above for the upper layer of cold poured mix. Preferably about 8 to about 11 parts by weight of binder are used, per 100 parts by weight of aggregate.
The thickness of the lower layer of hot mix will preferably be between approximately 2 and approximately 4 cm.
This first layer allows the reprofiling of the structure to be covered and ensures a first seal. A mortar of the type described above has a compactness of 96 to 98%. Permeability tests were carried out using an EDF permeameter. The coefficient is less than 10⁻¹² meters / second. This layer is therefore waterproof.

The bituminous binder of the intermediate layer essentially contains a bitumen. The bitumen can be chosen from pure bitumens, preferably from hard grade bitumens, by example of grade 40/50 or 20/30 or 10/20. The bitumen may advantageously be a bitumen modified by the addition of a macromolecular compound, for example an ethylene-vinyl acetate copolymer (EVA) or a styrene-butadiene-styrene copolymer (SBS). However, it is also possible to use the styrene butadiene rubber block copolymers (SBR) and the acrylic copolymers as well as various mixtures of these copolymers. The maximum content of copolymer is imposed by the limiting viscosity of the modified bitumen to which it flows by a heating and heat-insulated spreading ramp while remaining at a temperature below the degradation temperature of the copolymer.
The bituminous binder of the intermediate layer of the complex can also comprise a resin in proportions ranging from approximately 1 to approximately 10% by weight. Particularly preferred resins are terpene resins.
The thickness of the bituminous membrane is advantageously between 1 and 5 mm, which corresponds approximately to 1 to 5 kg / m² of binder.
The bituminous membrane can advantageously be coated, in a conventional manner, during a sanding operation, with fine particles, for example with ardoisine or with sandstone.

• a) on répand directement sur le tablier de l'ouvrage d'art, un vernis d'imprégnation à froid, ou une couche d'accrochage à l'émulsion spéciale de bitume-élastomère,
• b) on répand successivement la couche inférieure puis la couche intermédiaire du complexe d'étanchéïté conforme à la présente invention,
• c) on réalise éventuellement un sablage de la surface dudit complexe,
• d) on répand une couche d'enrobé coulé à froid.

The present invention also relates to a waterproof road coating process for an engineering structure apron, characterized in that the following operations are carried out:

• a) a cold impregnation varnish or a layer of adhesion to the special bitumen-elastomer emulsion is spread directly on the deck of the structure;
• b) successively spreading the lower layer and then the intermediate layer of the sealing complex according to the present invention,
• c) optionally sanding the surface of said complex,
• d) spreading a layer of cold-cast mix.

• on réalise l'étanchéïté des bordures et autres relevés dudit ouvrage d'art en plaçant un matériau du type classique, préfabriqué, contre lesdites bordures, en retombées, ou en pénétration,
• on répand ladite couche inférieure du complexe d'étanchéïté en ménageant un retrait par rapport auxdites bordures,
• on comble l'espace ainsi créé lors de l'application de ladite couche intermédiaire.

According to a particular characteristic, following step a)

• sealing of the edges and other statements of said work of art is carried out by placing a material of the conventional type, prefabricated, against said edges, in fallout, or in penetration,
• spreading said lower layer of the sealing complex while providing a setback relative to said edges,
• the space thus created is filled in during the application of said intermediate layer.

The use of elastomers makes it possible to give the complex better cohesion, better elasticity and good adhesiveness to the support. In addition, the fact of using the same elastomers in at least two layers out of three makes it possible to limit the number of raw materials and in this way to facilitate the execution of the complex.

The following examples illustrate, without limitation, the three layers of the waterproofing complex according to the invention.

EXAMPLE 1

Composition for the upper layer of cold-cast mix.

Mobilplast® sold by the applicant, containing 95% by weight of emulsifiable 80/100 bitumen, and 5% by weight of an EVA copolymer, was used as bituminous binder.

An emulsion was prepared having the following composition, expressed in kg:

La composition destinée à former la couche d'enrobé coule à froid a été préparée en malaxant le mélange suivant, dans lequel les proportions sont exprimées en parties en poids :

The characteristics of this emulsion are as follows:

The composition intended to form the cold-pouring coating layer was prepared by kneading the following mixture, in which the proportions are expressed in parts by weight:

EXAMPLE 2

Composition for the upper layer of cold-cast mix.

The emulsion prepared in Example 1 was used and the following composition was prepared, in the same manner as in Example 1:

EXAMPLE 3 Composition for the intermediate bituminous layer

EXAMPLE 4

Other composition for the upper layer of cold-cast asphalt

Mobilplast® sold by the applicant, containing 97% by weight of 80/100 emulsifiable bitumen, and 3% by weight of an EVA copolymer, was used as bituminous binder.

La composition destinée à former la couche d'enrobé coulé à froid a été préparée en malaxant le mélange suivant, dans lequel les proportions sont exprimées en parties en poids :

An emulsion was prepared having the following composition, expressed in kg:

The composition intended to form the layer of cold-cast mix was prepared by kneading the following mixture, in which the proportions are expressed in parts by weight:

EXAMPLE 5

Composition for the lower layer of hot mix

It was prepared by kneading the following mixture, in which the proportions are expressed in parts by weight:

EXAMPLE 6

Composition for the lower layer of hot mix

The composition intended to form the lower layer of hot mix was prepared by kneading the following mixture, in which the proportions are expressed in parts by weight:

Claims (11)

Sealing complex for a road structure apron, characterized in that it comprises: a lower layer of hot mix comprising, per 100 parts of aggregate, from approximately 8.5 to approximately 10.5% of a bituminous binder containing elastomers, and from approximately 11 to approximately 16% by weight of aggregate with a diameter of less than 80 µm, - an intermediate layer consisting essentially of a bituminous binder, and - an upper layer of cold-cast mix. Sealing complex according to claim 1, characterized in that the cold-cast mix of the upper layer consists of a bituminous binder in emulsion is an aggregate whose maximum particle size is less than about 10 mm. Sealing complex according to claim 2, characterized in that the aggregate of the upper layer is chosen from crushed sands. Sealing complex according to any one of Claims 1 to 3, characterized in that the cold-cast mix of the upper layer contains from approximately 6 to approximately 20 parts by weight of residual binder per 100 parts by weight of aggregate . Sealing complex according to any one of claims 1 to 4, characterized in that the bituminous binder of the coating of the lower layer and / or of the upper layer contains essentially a pure bitumen. Sealing complex according to any one of claims 1 to 4, characterized in that the bituminous binder of the coating of the lower layer and / or of the upper layer essentially contains a bitumen modified by the addition of thermoplastic copolymers. Sealing complex according to any one of claims 1 to 6, characterized in that the bituminous binder of the coating of the lower layer and / or of the upper layer also contains synthetic organic fibers. Sealing complex according to any one of claims 1 to 7, characterized in that the bituminous binder of the intermediate layer contains essentially a pure bitumen. Sealing complex according to any one of claims 1 to 7, characterized in that the bituminous binder of the intermediate layer essentially contains a bitumen modified by the addition of thermoplastic copolymers. Sealing complex according to any one of claims 1 to 9, characterized in that the bituminous binder of the intermediate layer contains from 1 to 10% by weight of a resin. Sealing complex according to claim 10, characterized in that the resin is a terpene resin.