Grid zone backfill

From the GMA Techline

RE: Backfill
I know you indicated sand was the ideal grid zone backfill. I suppose crushed limestone has a high installation damage reduction factor due to its angular nature. But what about a rounded river gravel?

We’re running out of ash as we near completion of an MSE wall, and a nearby sand/gravel quarry has a large stockpile of “pea gravel.”

(Brian | Kentucky)

Reply: Rounded river gravel would work with two obvious trade-offs:

1. less installation damage than quarried gravel, and
2. lower friction angle for stability.

Bob Koerner | GMA Techline