Gravel - Heat Island Reduction

Hi Abhinay,   Yes, you can. As long as you can provide the manufacturer’s documentation showing the SR value. Because natural concrete color still can meet the SR value requirement.   Best regards.

Agreed regarding using gravel, provided you can secure documentation from the provider of the reflectivity. I have asked in the past if we could include it and assume the default same value as concrete and was told no, we'd have to test it to get the info needed if the supplier couldn't provide it. For your second question, not sure what you mean by unbound...?

Loose gravel does not fall in to the Open-grid pavement system. I mistakenly put gravel in to that category for my documentation, because the LEED language for open-grid pavement system says (must be at least 50% unbound), and received the following feedback:
The open grid paving appears to be gravel. Open-grid pavement are system pavements that consist of loose substrates
supported by a grid of a more structurally sound grid or webbing. Pervious concrete and porous asphalt are not considered
open grid as they are considered bounded materials. Unbounded, loose substrates do not transfer and store heat like bound and compacted materials do. This item should be removed from the calculation.