1. Constitution of a pavement
A floor is composed of three elements:
- A mould (or a lower layer or a foundation) consisting of a material thickness selected and positioned so as to obtain a solid, stable platform, capable of receiving the body of the pavement.
- The body of the pavement itself, consisting of a reinforced or not reinforced concrete slab placed at the site of the installation and resting on the mould.
- A finish or a coating for compliance with specifications for geometric tolerances and use the pavement to the desired surface qualities, all ensuring a certain resistance to mechanical actions (such as those due to engine maintenance, to possible chemical attack, etc.).
2. Mould or inferior layer
The mould rests on the floor with partially removed topsoil, level and eventually consolidated and reorganized by pollution control drainage layer, if necessary.
In some cases, the soil at the site of the installation can be stable enough seats to directly receive the body of the pavement. This applies mainly rocky or stony soil and its reaction module is above 20 MPa/m.
This mould must have a finish that allows you to adjust with the utmost precision, the platform on which to penetrate the body of the pavement.
Can be done with gravel, cement or gravel - slag. Its mechanical results are also based on the consistency of compacted.
Most problems arise from long-term deformations. Also, the foundation must have certain physical and mechanical properties.
- Insensitivity to water
- Uniform load capacity and sufficient
3. Body of the pavement
For reasons as yet untested, the Professional Rules “Paving works” refer to the notions and notations required in the definition of the tensile strength of concrete.
Indeed, they define the bending breaking stress for flexion – traction (o8), the nominal resistance of concrete on flexion – traction (oN), according the standards CCBA 68, equally refer to the characteristic resistance (oCAR), as well as to the breaking stress for traction, measure through a Brazilian study. It seems to be than all these values should be given from essays, which specify neither the age of concrete, neither the number of test tubes, neither the mode of interpretation of the results.
The result is some pretty confusing prescriptions. In order to help the reader to which he can get bearings to, that it seems us useful to establish a mail board between these different slight knowledge (values of efforts in MPa) indicating besides the correlation brought nearer with the dosification of cement.
Therefore, the concrete of the body of the pavement should have a good tensile strength. It does not seem reasonable to come down from underneath the 300 kg/m3 for the dosification cement (CPA – 45).
In certain cases, it can be useful to use plasticizers and air propellers, as well as fibers of polypropylene to decrease the fisurization and the permeability of concrete.
For all the types of pavements, the best-suited framework is her welded grillage. For a bigger facility of installation and of positioning of the framework, he recommends to use panels preferentially with rollers.
In the case of requests in which they require for example an armed pavement (see post office box 3,3) can recur itself to custom-made panels, in order to find an optimization of the cost of steels.
The coating should be compatible with the mode of execution according to the Ground Rules BAEL and at least, equal to 20 mm.
The diameter of the welded employed grillages should not exceed of h/10 • h, that is the thickness of the body of the pavement.
The separation (“℮” o “Є”) or you should not exceed of:
- 2 h. (in case of localized loads)
- 3,5 h. ( if the pavement does not have to support distributed loads
The coating of the panels of the grillages welded in each direction should have been realized in such a way that the total anchoring is insured (chapter 1, titles 2.3.3 and 2.3.4).
4. Coating or finish
The election of a coating of ground is a must and it should not be underrated in any case. It is based in a thorough study of the different efforts related with the type of utilization of the pavement.
By way of example, the coatings of industrial grounds used more habitually, come true for integration of a mix of hard and cements granulated preparations, to the surface layer of the concrete of the pavement having grieved once his setting was begun, either for pulverization in dry of the hard granulated preparations for partition of a micro-mortar or else (incorporated coating). A coating cannot arrange at the same time of all the required qualities.
Therefore, often it is necessary to establish a commitment between various requirements that can be contradictory and consequently these should be classified under instructions of importance.