This 15" diameter aluminum base can be mounted permanently to a concrete or a paved surface or it can be used for temporary signs. The base comes with the hardware needed to attach your post to the base.  The green piece of u-channel post in the picture is just for demonstration and the green u-channel post isn't included in the kit.

This base can be used with 2lb-per-ft u-channel posts, square posts, or 2 3/8" pipe posts. It works with a 2 lb-per-foot u-channel post, but it will not work with a 1.12 lb-per-foot u-channel post. If you are using round posts, holes will need to be drilled in the round posts. This base comes with two 2.5" long bolts and two nuts and that hardware is needed to attach your u-channel post to the stub.

To attach this aluminum base securely to the concrete, you will need three concrete anchor bolts and a drill with a masonry bit. A variety of 5/8" concrete anchors bolts should be available at your local hardware store. If you install it on asphalt, 12" asphalt "spikes" are recommended and available at some hardware stores and from various online stores.