I have been asked to repair an old terrazzo shower tray. Much of the concrete in the terrazzo has eroded away, but the stones are intact and not loose. My thought is that I can use a concrete bonding agent to fill in some new concrete, let it set, and then grind/hone it to a nice finish. My only hesitation is that there is only about 1/4" of missing concrete, and I want to make sure that it bonds correctly and does not fall apart quickly. Does anyone have any wisdom as to the best way of going about this?

Thanks,

PJ