Tough impermeable, compact limestones are unsuitable. After many years of disuse, it would be surprising if mistakes were not made with hydraulic lime, especially when specification is sparse and experience limited. Unfortunately, it is human nature to blame the materials when things go wrong. Provided the source stone is well selected, the burning carefully controlled and the hydration, mixing, placing and curing properly carried out, hydraulic limes will perform a range of work consistently well. The term 'hydraulic lime' covers materials which vary in properties such as setting times and strength development, but they are never to be thought of or used as a cement substitute.
Lime is lime.
Workability, low shrinkage, salt and frost resistance, adequate compressive and good flexural strengths are the characteristics of these materials. They have a long history and a recorded performance history at least since the 1750s. In 1997, there is the beginning of a revival in British production and some excellent imported material from the continent, as there has been since the 17th century. These are materials worth getting to know again, whether for historic building maintenance or for new construction. A Practical and Scientific Treatise on Calcareous Mortars and Cements .