You can pound 3/4″ or thicker stakes right into asphalt but it is work. The guys that work for tent companies are used to it. You can use a good cordless hammer drill with 1/2″ chuck and masonary bit to pre drill the asphalt. You will need some water while drilling. Any good steel fabricator will have steel rod.
Another idea would be to weld 12″ x 12″ x 11 ga steel plate to the bottom of your tent poles and then use sand bags to hold the plated poles down.