What sand do I use to re-secure pavers?
Polymeric sand is a fine sand that is combined with additives that form a binding agent when exposed to water. Silica is such as an additive and is often used to help lock the fine sand particles together. As the sand particles fuse, the joint between two patio pavers becomes impenetrable and the pavers are locked in place.
https://unilock.com/articles/what-is-polymeric-sand-and-how-is-it-used-for-locking-patio-pavers-yorktown-heights-ny/

Through particle bonding a solid surface is formed that resists weed growth. Pavers move, though, and cracks will exist that allow some weeds to establish. Periodic herbicide application or weed-whacking may be required, depending on traffic, sun exposure, etc.
&quot;Paver sand&quot; sold at home improvement stores may be polymeric sand. You'll need to read the label.