Weeds will germinate in regular sand. We use polymeric sand in our patios. My husband and I own a patio business. Sweep it in dry on dry patio. Remove all excess from pavers then mist lightly. Stay off patio for 24 hours. This sand will bond together like concrete and will not blow away or wash out.
A creative, low cost way to deal with a cracking driveway. First you widen the cracks a little, then add reinforcincing rebar and concrete, top with rocks and morter in the stones. Great inexpensive solution to and expensive replacement!