Provlies GmbH - Slide


1. When shall Asphalt nonwoven geotextile be used?

Provlies RVS Asphalt is used in all cases where reflective cracking has appeared in the existing road surface, and where crack propagation into the new overlay shall be retarded.

2. Can asphalt with Provlies RVS Asphalt be recycled?

Asphalt road surfaces with Provlies can be milled without any problems. The material can then be recycled to new asphalt mix. Provlies is environmentally neutral, produce no by-products and can be deposited.

3. What is the “sealing effect' of Provlies RVS Asphalt?

The paving product keeps the bitumen in its place and prevents its running-off. When Provlies is pressed into the tack coat applied in a suitable quantity (1.2 kg/m²), the old road surface is sealed which prevents the penetration of surface water and oxygen. This permanently guarantees the bearing capacity of the base course.

4. What is the “stress relieving effect' of Provlies RVS Asphalt?

The propagation of stresses between old road surface and new overlay is reduced and /or retarded by the bitumen impregnated Provlies. This reduces and/or retards the formation of reflective cracks in the new surface.

5. What is the “adhesive bonding effect' of Provlies RVS Asphalt?

The optimum bitumen retention capability and the flexibility of Provlies allowing perfect adaptation to uneven surfaces guarantees optimum and uniform adhesive bonding between old and new asphalt. The life-time of the road is therefore considerably increased.

6. What type of tack coat is recommended - straight bitumen or emulsion?

Generally, both types may be used in combination with Provlies RVS Asphalt. Pure bitumen is recommended when there is a lack of time, as the paving felt can be installed immediately after tack coat application. When emulsions (> 65% bitumen content) are used, the curing of the bitumen has to be awaited. Depending on surface temperature, air temperature and humidity, this can take 15 to 30 minutes.  Local availability, type and size of the project etc. are decisive factors for the choice of the tack coat type.

7. Can also emulsion with less than 60% bitumen content be used as tack coat?

No, as after evaporation of the water, a bitumen content of < 65% is insufficient to achieve adequate sealing. Furthermore, for optimum adhesive bonding the bitumen content must be > 50%.

8. Can polymer modified tack coat be used?

Yes, compared to other tack coat materials, polymer-modified bitumen has an improved adhesive effect, resulting in an extended life-time of the structure. When polymer-modified bitumen is used in the asphalt concrete, it is recommended to use the same bitumen as tack coat for paving felt.

9. What is the typical construction sequence when Provlies is used?

a)    Clean the road surface
b)    Fill cracks (>4mm) and potholes, alternatively mill and apply a leveling layer
c)    Apply effective tack coat quantity (1.2 kg/m²)
d)    Unroll Provlies RVS Asphalt into the tack coat
e)    Install asphalt concrete of minimum 40mm layer thickness, or apply a surface dressing Reinigung der Fahrbahn

Generally, installation shall be done only at good weather conditions!

10. Can the thickness of the asphalt concrete overlay be reduced when Provlies is used?

The use of Provlies RVS Asphalt does not increase the bearing capacity of the asphalt layers; therefore a reduction of overly thickness is not possible. Type and thickness mainly depend on the applied traffic load. Provlies reduces local stresses over existing cracks, thereby increasing the life-time of the new overlay by a factor of 3 to 4.

11. What overlay thicknes is required?

The minimum overlay thickness shall be 40mm. This guarantees adequate installation temperature to achieve an optimum bonding of the individual layers.

12. Are adjacent Provlies panels overlapped?

Longitudinal and transversal joints of Provlies need not to be overlapped. Unavoidable overlapping such as in curves shall be cut off or glued with additional bitumen.

13. Can asphalt nonwoven geotextile be installed at all wheater conditions?

Provlies shall be installed only at dry weather. Only this leads to an optimum adhesive bonding of the layers which is a prerequisite of this maintenance method.

14. How is the installation during running traffic?

Generally, it is recommended to install the overlay immediately after unrolling Provlies. However, when traffic situation requires the traffic to run temporarily over the installed Provlies, a speed limit of < 30 km/h is essential to avoid excessive slipping.

15. What are the functions of Provlies RVS Asphalt?

The function of Asphalt Nonwoven Geotextile is to retard the formation of reflective cracks in the overlay by allowing controlled horizontal movements in the interlayer. Furthermore, the penetration of surface water and oxygen into the lower layers is prevented, with the Provlies RVS Asphalt acting as bitumen storage. A reinforcing effect is only achieved with an optimum adhesive bonding and under low strains. Experience has shown that the use of paving felts and composites can extend the life-time by a factor of 3 to 4. This increase of life-time combined with a decrease of maintenance costs results in a total cost reduction up to 30%.

16. What tack coat quantity is required for optimum adhesive bonding?

The optimum bitumen quantity to achieve adequate adhesive bonding is 1.2 kg/m², depending on the condition of the old surface (voids content, surface roughness, number of cracks etc.).

17. Who can be seen during installation that enough tack coat was applied?

When the laying machine runs over the fabric, or when walking on it, wheel paths and footprints shall be clearly visible. If not, the tack coat quantity must be increased. It can be required to change the recommended tack coat quantity of 1.2 kg/m². According to RVS 08.16.02 the following correction factors shall be applied:  

Condition of old road surface / Effective tack coat kg/m²

Rough, uneven concrete / +0.10
Severely cracked surface / +0.10
High surface roughness / +0.10
High voids content of the sub grade / +0.10
Low voids content / -0.10
Low surface roughness / -0.10
(Source: RVS 08.16.02)

18. How is Provlies RVS Asphalt installed professionally?

The type of installation depends on the size of the project, and can be done either by hand or by unrolling machine. The products shall be installed free of folds and wrinkles.

19. Can Provlies RVS Asphalt be installed in curves?

Yes, installation in curves is possible. You have to provide adequate tension to the product during installation.

20. At which temperature can asphalt concrete be installed on top of the polypropylene nonwoven geotextile?

Normally, the mixing temperature of asphalt concrete is 150 to 170°C. In practice, the installation temperature is 130 to 150°C in order to achieve a proper compaction of the asphalt.
The melting point of Polypropylene (PP) is above 165°C.

21. At which temperature shall the bitumen be applied on polypropylene nonwoven geotextile in surface dressing applications?

For surface dressings, emulsions shall be used, with an installation temperature of 50 to 70°C.

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