Aerogels are mentioned in both Red and Green Mars - Mostly as pillars for the tents, but KSR mentions "airgels" (spelling in my copy) as an insulation layer in the tent material too.
That seems odd. With the large pressure difference support pillars seem unnecessary for tents. Why did they need such exotic support pillars?
In the book "tents" euphemistically refers to tenting that encloses small towns. Also the tent fabric was a multi-layered thing (one layer was to absorb some radiation). Imagine this is why supports were seen as necessary.
He wrote that as pressure increased due to terraforming projects, the tents needed more support.