Crumbling steps.

[Unclebill]

Last year my wife took a pressure washer to our back steps as they were mossy and slippery. Unfortunately she used too high a pressure and has washed away the smooth top coat of cement/concrete and now the small pebbles and filler? under the lost top coat are crumbling away.
Can someone help with suggestions that a ham-fisted D-I-Y er can undertake to restore our back steps to their former glory??
:?