Can you make particles affect a rigid body? I am trying to crumble a block like in the gif below. Is there a way to have particles act like bullets and crumble the block? - Here I have just animated some spheres to try and do the same thing. 



I have only been able to make the particles bounce off surfaces but the actual rigid body object's are never affected. i.e they stay put.



I am using cell fracture and bullet constraints for the block in the top image. 

If it's not possible then is there a way to have a block 'crumble' away using forces rather than particles? 

Thanks
Normally, no - particles do not impart any force on a Rigid Body. However, I'm currently working on a patch to Blender to do just this. It's only experimental at the moment but I've made some good progress. Also trying to get interaction with Soft Body and Cloth and looking to improve the collision between Rigid Body and Soft Body/Cloth as that's also currently lacking. I'll add more when I've anything to add but for now here's a little teaser :