Really and trulu you should have asked two questions, as these are two separate terms.

I agree that riego de imprimación = prime coat = of penentration grade, goes under binder course

1. What are Prime Coats?

Many pavements particularly lower traffic pavements are constructed with gravel or granular material. Often roads have been constructed as gravel roads and an upgrade is required. If Emulsions are applied directly to granular pavements, especially high binder content chip seal emulsions or very quick set slurry emulsions they can fail to wet the surface of the pavement creating poor adhesion. A prime coat can over come this.
In the past prime coats have been based on cutbacks but VSS Emultech Emulprime 1000T™ is based on a special emulsion.
http://www.slurry.com/index.php/paving-services/prime-coat.h...

Prime coat
An application of asphalt primer to an absorbent surface. Often used to prepare an untreated base for an asphalt surface. The prime coat penetrates or is mixed into the surface of the base and plugs the voids, hardens the top and helps bind it to the overlying asphalt course.
http://www.pavementinteractive.org/index.php?title=Glossary

riego de curado = seal coat = goes on top of surface coat

What is Seal Coating?
Seal Coating is a thin asphaltic treatment used to protect pavement surfaces from UV radiation and oxidation. Seal coat may contain asphaltic or coal tar emulsion, fillers, sand, polymer latex, fibres and pigments. It depends on the application.
http://www.slurry.com/index.php/paving-services/seal-coat.ht...

Seal coat
A collective term for several different kinds of thin surface treatments used to improve the surface texture and protect an HMA surface. Seal coats include fog seals, slurry seals, microsurfacing, and BSTs.
http://www.pavementinteractive.org/index.php?title=Glossary

Please see this link for an explanation of the terms in Spanish:

http://www.carreteros.org/normativa/diccionario/r.htm