Short focal length range lenses tend to not have much blur unless you shoot at an EXTREMELY low focal ratio. Sure, you'd get some blur if you used something like the EF-S 17-55mm f/2.8... but it wont be a lot (you'll get some if you keep your subject close, a big separation between subject and background, use f/2.8 and shoot at the 55mm end. But you'd get more blur using the prime focus EF 50mm f/1.8 STM.) If you want strong blur with high quality bokeh then you'd be better off getting a longer focal length lens (with a low focal ratio) like the 85mm f/1.8 or the 135mm f/2, etc.
Even with my full-frame body and the 24-70mm f/2.8 lens, I get a bit of blur, but nothing that can compete with my primes or my longer lenses.