Spanish to English Tech/Engineering Construction / Civil Engineering Consulting

I'm working on a translation for a firm that provides consulting services in a variety of fields and the text provides a brief description of each.

I've come across "firmes" and "auscultación de firmes". I've come up with "road surface surveying" or "roadway surface surveying", but with "aeropuertos" in the content, it throws me off.
Here is what is in the source:

Ausculation de firmes.
Auscultación estructural y estructural de carreteras y aeropuertos.
Sistemas de gestión de firmes

I'd appreciate your help.