In order to obtain this trophy you must destroy all the red blinking bombs planted in the streets around Gotham.
Some of the final ordinance don't unlock until you complete a specific task:
When you find the ordinance, you must attach your wire to it and press
to install a virus, then you must take part in tank battles with varying degrees of difficulty.
Once you complete the battle you must hook back up with the ordinance, rev your engine and make it explode.
Here is a list of all ordinance locations
Bleake Island Locations: - (2110,-2930) (1800,-2420) (1910,-2670)(2360,-2900)
Miagani Island Locations - (3280,-2200) (3000,-2300) (2900,-2730) (3050,-2920) (3160,-2730)
Founders' Island Locations - (2140,-1910) (2040,-1570) (2270,-1540)
(2750,-1740) (2940,-1450)
Here is a video from Drawohkan showing you the locations and how to complete this trophy