EXPERIMENTAL SECTION: DIFFERENT BASES ON CEMENTED taxiways.
An experiment carried out 18 months ago shows how the use of bituminous treatments reduce the reflection surface cracks.
C.V.C held in Route 69 in Montevideo in early 2016 an interesting experimental section of Portland cement stabilized base which they were applied different layers of rolling to see its evolution:
1. Hot asphalt layer of asphalt AC20 3cm
2.- Bituminous treatment Simple -TBS- fog irrigation (14-20mm arid emulsion IRRIGATION BITAFAL 65 )
3. Cape seal (TBS with aggregate and emulsion 14-20mm IRRIGATION BITAFAL 65 + Micro Type II TMN 5mm emulsion BITAFLEX MICRO 62 P25)
4.- microsurfacing Type III (TMN 10mm emulsion BITAFLEX MICRO 62 P25)
After 18 months in service you can determine that all taxiways are used in very good condition overall and are alternatives to consider when protecting a stabilized with cement.
As reflection of shrinkage cracks in the cemented basis substantial differences exist between each of the layers used that detail below.
STABILIZED BASE:
The cement stabilized performed looking for a simple compressive strength of between 15 and 20 Kg / cm2. He was executed in place with a cold recycler and no crazing was performed. Irrigation curing was performed with emulsion IRRIGATION BITAFAL 65 and gravillín.
Wearing courses:
After 18 months of service shows that:
1. Hot asphalt layer of asphalt AC20 3cm. The cracks in this case are transverse to the roadway between 3 and 5 m. Also it is shown in much of the length of the longitudinal crack in the shaft which corresponds to the overlapping of the execution of the cement base.
2. Treatment Bituminous Simple irrigation fog (14-20mm arid emulsion IRRIGATION BITAFAL 65 ). Fissures surface but are difficult to identify the observed are between 9 and 18 m and no longitudinal crack is identified. In some identified fissure could be seen a slight loosening of aggregate.
3. Cape seal (TBS with aggregate and emulsion 14-20mm IRRIGATION BITAFAL 65 + Micro Type II TMN 5mm emulsion BITAFLEX MICRO 62 P25). In this case the cracks are clearly visible because the smooth surface which achieves the Micro Type II. They are transverse between 5 and 12 m apart. Nor longitudinal fissure of the overlap of the base shown.
4.- microsurfacing Type III (TMN 10mm emulsion BITAFLEX MICRO 62 P25). In this section transverse cracks between 2 and 3 m apart and longitudinal cracks of overlap almost the whole section are identified.
PRIMARY CONCLUSIONS (First 18 months)
• Bituminous simple treatment is the wearing at the time shows better performance in the reflection of cracking, not so much so in the comfort of the user (and neighbors) because it is quite noisy. (Patch initial sand: 3.75 mm). Something that could easily be solved with a finer stone or a sealing treatment.
• Then follow the Cape Seal with a very good performance against the reflection of cracks which obviously is contributed by the Bituminous simple treatment. In this case the sealed surface gives quiet and safe running. (Patch initial arena: 0.95 mm)
• The folder has a good asphalt performance but still has more Cracking the Cape Seal for security and is thinner than the rest of the taxiways (Patch initial arena: 0.45 mm) Macrotexture. In turn it would have to make an economic comparison against the cold techniques, but at the same cost would be reasonable to use treatments or Cape Seal.
• The Micro Type III had the worst performance against reflection even crack your Macrotexture is suitable (Patch initial arena: 1.10 mm)
For future tranches of these features we suggest:
Perform 1_ TBS with modified emulsion BITAFLEX P25 or P40 65 IRRIGATION to further reduce the reflection of cracks and have more cohesion in the asphalt to prevent premature detachment.
2_ Test with TBS with a little fine stone (10 to 14 mm) and made in Australia and New Zealand, to have good resistance to cracks without neglecting the noise generated.
3_ Perform a double treatment Trabado (TDT) with modified emulsion BITAFLEX P25 or P40 65 IRRIGATION to contemplate the above as well as high yields of work and minimal waste of materials.
