To provide access I was going to put some stepping stones in the bog I am contemplating, I assume these need to be mounted on 'pillars' which are in turn sit on the liner. Since I dont have real stone the stepping stones would be concrete and the pillars will either be concrete or what is called thermalite. The latter looks like aerated cement.

Will the bog dissolve the pillar etc?

Is concrete, even 20-30 year old concrete/cement, bad for a bog? I assume there will be some dissolving but I dont know how rapid this will be or its effect on the bog?