Glass beads surface dressing test section

Transcription

1 Glass beads surface dressing test section O. Franchomme (COLAS SA) 1/ 24

2 Objective : Build a test section With an idealized texture Based on spherical patterns 2/ 24

3 Design elements Beads nature should not interfere with the texture profile measurements, The surface dressing must be applied on a perfectly smooth surface, The beads must stick to the asphalt support, The surface dressing must resist while the test vehicle pass by several times at 90 km/h 3/ 24

4 Choice of the beads Nature : glass beads Surface : Frosted the profile measurement is not affected by reflections ensure a better sticking Diameter : 5 mm ± 0.3 mm. 4/ 24

5 Construction technique Support : Asphalt layer Average texture depth : 1mm Glass beads Stick «Voidfilling» Asphalt layer 5/ 24

6 Laboratory Tests 6/ 24

7 Solution 1 A classical surface dressing Void filling : Bituminous mixture Binder : Bitumen emulsion Bitumen emulsion «Voidfilling» bituminous mixture Asphalt layer Glass beads 7/ 24

8 Laboratory tests - Adhesion test according to NF EN standard - Laboratory surface dressing application 8/ 24

9 Adhesion tests : Between glass beads and bitumen emulsion Test consists in estimating the behaviour of a binder film (in this case emulsion) on an aggregate (here glass beads). After 72 hours in water at 60 C Residual film must cover more than 75% of the aggregate surface. 9/ 24

10 Adhesion tests : Between glass beads and bitumen emulsion Results After conservation, whichever emulsion was tested, less than 50 % of the beads surface was covered by the binder film Poorly coated glass beads 10 / 24

11 Laboratory surface dressing application Tests were carried out with different bitumen emulsions and frosted glass beads The samples behaviour was regularly observed to estimate the breaking time for emulsion. 11 / 24

12 Laboratory surface dressing application Aspect of the Surface Dressing after 1h30 The emulsion did not break totally Aspect of the Surface Dressing after 24 h No adhesion of the beads to the support layer 12 / 24

13 Solution 1 Conclusions laboratory tests Solution 1 proved to be impossible For 2 reasons : The emulsion breaking time was too long ( > 2 h) The adhesion between glass beads and emulsion was not satisfactory. 13 / 24

14 Solution 2 A surface dressing with resin Void filling : methacrylic resin with filler Binder : Resin type Colgrip Resin COLGRIP «Voidfilling» methacrylic resin Asphalt layer Glass beads 14 / 24

15 Solution 2 A surface dressing with resin The sample is manufactured according to the method that will be applied on site: Application of the Serac resin with a smooth spatula One hour delay to allow for resin to harden. Application of the Colgrip SE resin with a 5 mm jagged scraper to obtain a 2.5 mm thick binder layer. This thickness allows sealing the beads on half their diameter. Glass beads are then spread in excess. After the Colgrip resin hardens, excess glass beads are removed by sweeping. 15 / 24

16 Solution 2 A surface dressing with resin The beads that were stuck this way cannot be removed from the support. Surface aspect the laboratory sample This technique is therefore validated 16 / 24

17 Glass beads test section 17 / 24

18 Glass beads test section Test section was built on September 16th, The weather was cloudy, with an outside temperature ranging from 10 to 17 C. 18 / 24

19 Phase 1: Application of Void filling Support preparation Sweaping Limitation of the area to be covered 19 / 24

20 Phase 1: Application of Void filling Support preparation SERAC is applied with a smooth spatula With SERAC Without SERAC Visual aspect after SERAC is applied 20 / 24

21 Phase 2: Application of the Colgrip SE Colgrip resin is applied with a 5 mm jagged scraper to obtain a 2.5 mm thick layer Glass beads are manually spread in excess 21 / 24

22 Phase 2: Application of the Colgrip SE Visual aspect of the test surface before excess glass beads are removed by sweeping 22 / 24

23 Phase 3: Surface sweeping to remove the excess glass beads Global view of the resin and glass beads test section 23 / 24

24 Thanks for your attention 24 / 24