After some feed back about lquid limestone for around pool.

My wife and I had a pool installed before Christmas last year, have a few issues which need recitfying by pool company, once these have been sorted we are looking at have liquid limestone poured. I'm aware of having the whole area compacted with either a normal compactor (within 600 odd mm) of pool and pencil compacted close to pool.                                                                                                                                                                                       Does anyone know much about expansion joins required. Liquid limestone will be poured on the inside of a retaining wall, was planning on putting expansion joint on these edges and also elsewhere as recommended by installer.                                                                                                                              Is it worth putting down black plastic underneath?                                                                                                                                                      What would be the minimum size mesh to use?                                                                                                                                                             Can anyone recommend a company who does a good job                                                                                                                                                                                                                                                                                                                                                                                                                                         .