Is posible use this SSR for PWM speed control of AC motor directly?
The others already mentioned the problem with zero crossing and the solution.
Besides this - is your motor even able to be controlled by PWM? This only works for universal motors - but not for induction motors.
If it is an induction motor you need to alter frequency - PWM will have no effect.
Also be aware that Motors are inductive devices - your solid state relais may need a protection circuit ("snubber") to avoid being killed by high voltage spikes.