Short version: It's pretty much impossible to build a bin that can withstand an explosion, is economically viable, and can be used in the same situations as normal bins.

The solutions that you see in the UK after various terrorist bombings are:

1) Bins get removed. If you look at chunks of London which are high-risk "targets" you will see a lack of public waste-bins.

2) Bins get changed to be less useful for hiding devices in. For example the UK rail stations often have bins that are just a transparent plastic bag hanging from a hoop. Any large/heavy device would be obvious quite quickly.

Both of these have associated costs of course (rubbish on the street and more frequent changing of bins respectively).

The situation in Istanbul, for many, many years, was a complete lack of public waste bins. That has recently changed, but many are similar to those you mention in your second point. One caveat, however, is that bombers have even settled for cheap plastic bags to house devices (though mostly for specific assassinations, rather than mass attacks).

It depends on your goal, ultimately. Install bomb-proof trash bins and bombers will simply adjust their tactics, and the government will be out a great deal of expense and inconvenience to have only made rubbish safer from attack.

Unfortunately I don't think there's an easy component x which you could test for.

How about weight though? I imagine most bombs are considerably heavier than normal refuse. Could we add scales to bins and notify authorities that it should be examined if the weight suddenly increases by 2+ standard deviations, say.

I suppose this could be worked around by dropping explosive material piecemeal into the bin so this would have to be paired with an effective surveillance system to pick up on this behaviour.

Those look pretty good... but I wonder what "exceptional blast mitigation" means. It would be interesting to see this tested against a range of commonly used professional and improvised explosive devices.

MythBusters anyone?