I have an expansion joint that I would like to fill. The EJ is located at the point underneath the roof of my carport where the concrete carport slab meets the concrete driveway. Although this is under the edge of the carport roof, this EJ does get wet from a hard or wind driven rain. This EJ is almost 3/4" wide and is quite deep. I am thinking that I can use some sand to fill in the bottom first and then use a backer rod before applying a type of sealant. Lowe's has two things that might work. 1) DAP Concrete and Mortar Filler and Sealant - $4.16 per 10.1 oz tube. 2) Commercial Grade Quikrete Polyurethane Sealant (Self-Leveling) - $6.76 per 10.1 oz tube. Any suggestions? Thanks in advance.