FR2647822A3 - ROAD COATING COMPOSITION AND METHOD FOR MANUFACTURING A COATING - Google Patents

Abstract

A road surfacing composition comprising a hydrocarbon concrete known per se and fibers of the acrylonitrile type, preferably in the form of kidneys, in an amount of 0.1 to 1% by weight is described. Such a composition has good resistance to rutting.

Description

ROAD COATING COMPOSITION AND METHOD FOR THE

MANUFACTURE OF A COATING.

  The present invention relates to a compound

  tion for an improved road surface which pre-

  feels increased resistance to the ornamentation of the top and / or base layers, in particular a road surface in hydrocarbon concrete. It also relates to a method for

the manufacture of said coating.

  In document US Pat. No. 3,728,211, the use of synthetic or mineral fibers, such as glass fibers or nylon fibers, has already been described in asphalt.

  From document US-A-4 360 483, the utility is known.

  glass fibers treated on the surface in

  bitumen compositions for strengthening thereof.

  The document EP-A-0 058 290 relates to a com-

  asphalt position with mineral fibers.

  Document EP-A-0 018 491 describes a reinforcement for bituminous coatings, which consists of fibers and of polypropylene fiber nets. However, it has been found that the polypropylene fibers do not exhibit adequate behavior at the processing temperatures of the bitumen compositions, in particular at temperatures

higher than 160oC.

  The object of the present invention is to provide

  nir a composition intended for a road surface which

  exice an increase in the energy to be supplied for the rup-

  ture. An additional aim of the present invention consists in providing a composition intended for a coating

  road whose cohesion of the hydrocarbon binder is increased

  mented and in particular a composition of the aforementioned type which has better resistance to deformation, creep and rutting. The aims of the present invention are achieved by a composition comprising a hydrocarbon concrete known per se and fibers of the acrylonitrile type, preferably

kidney shaped.

  In the remainder of the present invention, it is meant

  by "hydrocarbon concrete" any mixture of a hydrocarbon binder

  good with mineral fillers such as gravels, gravels

  lons, sand, filler..etc. "Hydrocarbon binder" means

  any type of binder, based on bitumen, pitch or a medium

  diaper of these as well as the binders modified by

  additions of polymers and / or oils of all kinds.

  According to a particularly pre-

  fairy, acrylonitrile fibers have a length

  overall between 2 and 20 mm.

  According to the invention, the composition contains the

  your acrylonitrile fibers in a content ranging from 0.1 to 1%. Indeed, a content lower than 0.1% does not provide

  of economically interesting result and at higher levels

  below 1%, mixing difficulties are observed,

  while not obtaining a significantly improved result.

  In accordance with another aspect, the present invention

  tion relates to a process for manufacturing a

  road clothing, in which a hydrocarbon concrete is mixed

  boné known per se, hot, with fibers of the acryloni- type

  trile. The mixture thus obtained is applied to the support to

  cover and compacting is carried out in a conventional manner.

  The cohesion of the road surface thus obtained on the support to be covered depends essentially on three parameters: 1. the inter and intra molecular forces, intrinsic characteristic of the material: 2. the adhesion forces, adhesion is conditioned: - by chemical nature of the bodies in contact; - by preparing the surfaces of the bodies in contact:

  the invention extends to any addition to the hydrocarbon binder

  boné whose goal is to improve the bond.

  The cohesion will be all the greater as: - the coating of the fibers with the bitumen is high;

  - the surface development of the fibers is large.

  This means that, for a given fiber weight,

  the fiber configuration must be such that they present

  try as much area as possible, which can be achieved

  by reducing the fiber section and / or the type of dryness

  tion. It is quite obvious that this surface development must not exceed a certain value for a given content of hydrocarbon binder, in order to guarantee that the coating

fibers may be total.

  It can be seen that the incorporated fibers are not substantially deformed during the compacting operation. They therefore do not link the aggregates

  between them and are not necessarily related to each other.

  The coating according to the present invention substantially improves the creep resistance, or in other words, the thermal susceptibility of the

  "binding" phase. Hydrocarbon concrete manufactured according to the pre-

  invention therefore does not present a sub-

  stantielle of the rupture stress in compression. However, the breaking energy is multiplied by a factor

  1.5 to 2, compared to a conventional hydrocarbon concrete.

  This results in a considerable improvement in resistance

  rutting, under static, dynamic or heavy loads

  periodically or under the effect of an increase in temperature

  ture. It is important to note that a complete coating of

  each fiber by the hydrocarbon binder must be guaranteed.

  To do this, the incorporation of the fibers is preferably

  performed in the hydrocarbon concrete mixing plant

goodness.

  Incorporation of fibers on site cannot be considered, provided that complete coating is guaranteed.

  Furthermore, it should be noted that

  Nution of the thermal susceptibility of the binder can also be obtained by adding filler or by using

  harder binders. But these techniques reduce the deformation

  bility of the binder, and therefore its resistance to cracking,

  disadvantages that the invention does not present.

  We can also use a binder which is

  treated to increase adhesion or durability of the

fiber inheritance.

  The invention is described in more detail below in the examples supported by the drawings in which: - Figure 1 is a table of results of a creep test not containing fibers; - Figures 2 and 3 are results tables of creep tests on compositions containing acrylonitryl fibers; and - Figure 4 is a representation of the test results

rutting.

  In the various tests described below, compositions with various fiber contents were compared, the

  hydrocarbon concrete being kept strictly identical.

  The composition contains: 10/20 aggregate: 8%

7/10: 29.4%

2/7: 17%

0/2: 37%

  filler: 8.6% bitumen: 6% and fibers: o, 3% test piece n 1 0.3% test piece n 2 0% test piece n 3

  The mixing is carried out in a heated mixer

  fant, at 160 C. The mixture is then placed in a mold (100 x 100 x 5 cm) where it is compacted using a plate

vibrant.

  Rutting tests have been carried out and the purpose of this test is to estimate under experimental conditions!

  data, the susceptibility to rutting of a hydro-

  compacted carbonaceous. The surface of a mixing test tube

  hydrocarbon is subjected to the action of two loaded wheels.

  A core of + 63 cm in diameter and 5 cm thick is placed in a mold fixed on the turntable of the traffic simulator. The two wheels rotate in a fixed vertical plane, around a horizontal axis. These

  wheels are loaded by means of a series of weights of 10 kg.

  Characteristics: - maximum speed: + 1 m / s - weight applied to each wheel: 40 kg - Vredestein tires 260 x 85 - 4 P / R

- test temperature of 40 + 1IC.

  A counter determines the number of

  ruts and rutting depth measurements are performed

  killed using a comparator. Actions have been taken

  along two perpendicular diameters.

  The results are shown in Figure 4.

  The impression measurements gave the following maximum values: test piece 1: d = 3.6 mm - test piece 2: d = 3.6 mm - test piece 3: d = 9.6 mm

  There is therefore a marked improvement in the behavior

  of the compositions according to the invention.

  The advantages of the composition in accordance with the pre-

  sente invention are also highlighted by an essay

of creep.

  MARSHALL type carrots (diameter 10 cm; h

  = 6.5 cm) are placed in a thermostatically controlled glycerin bath.

  rine; a temperature programmer allows you to

laugh it continuously.

  Additional agitation is planned to

  to improve the uniformity of the temperature in the bath.

  Weights are placed on the test piece so that

  the pressure exerted on it is 1.5 kg / cm2. A com-

  parateur allows to follow the evolution and the behavior of the

  material as a function of temperature.

  Various compositions have been tested,

  in particular a composition of bitumen containing no fi-

  bre (fi; ure 1), a bi: ume composition containing acryvlonitrle fibers VT 10 30/6 (DOLANIT HOECHST) (Figure 2) and a composition containing acrylonitrile fibers vF 1 00/6 (DOLANIT HOECHST) (fig. 3), each at a rate of 0.3%.

  The results obtained are shown in the figures.

  res 2 and 3 in the cuelles! the recess (in mm) is given as a function of the temperature ('C). It can easily be seen that the behavior of the composition containing fibers is significantly better at temperatures.

of actual use.

  According to a particularly preferred embodiment, the acrylonitrile fibers have a diameter included

between 10 and 120 nm.

  The road surface according to the invention can be used as a wear layer or as an undercoat, possibly combined with a layer made up of

  a hydrocarbon concrete comprising metallized fibers.

  In addition to good surface development,

  By virtue of the adhesion in the bitumen composition, the kidney-shaped fibers further improve the adhesion.

  by a complementary mechanism which is a mechanical effect

  picnic where the binder is "stuck" in the hollow

  between the two kidney-shaped bulges.

  In addition, the kidney-shaped fibers have a low tendency to agglomerate during the kneading of the composition because, to do this, the scient fibers should be oriented face to face so that the

  bombings "fit together" in the hollows: what is static

tlsticuemenz unlikely.

Claims (7)

  1. A road surface composition comprising a hydrocarbon concrete known per se and fibers of the acrylonitrile type, preferably in the form of kidneys.   2. Composition according to claim 1 character-   laughed at in that the fibers have an outside length everything between 2 and 20 mm.   3. Composition according to claim 1 or 2 characterized in that it contains said fibers   according to a content ranging from 0.1 to 1 X by weight.   4. Composition according to any one of the res-   previous indications, characterized in that the fibers   have a diameter between 10 and 120 μm.   5. Method for manufacturing a coating   road characterized in that a hydro concrete is mixed   carbonaceous of the type known per se when hot with fibers of the acrylonitrile type. preferably in the form of kidneys, at a rate of 0.1 to 1% by weight, in that the mixture thus obtained is applied to the support to be covered and   compacting is carried out in a conventional manner.   6. Use of the composition according to one   any of claims 1 to 4 as a wear layer   or as an undercoat, possibly combined with a layer constituted by a hydrocarbon concrete comprising metallic fibers.   7. Use of the composition according to one   any of claims 1 to 4 as a resist layer   both deformation by rutting.