Main factor affecting the recycling are

1.  The physical form of concrete can make handling and recycling difficult , especially if reinfoced . 
2. Recycling concrete containing steel involve breaking up in-situ frames and then reducing columns and beams to more manageable size by large scissor action machines which cut through the concrete and steel . 
3. Pure crushed concrete is normally contaiminated by brick and other waste which may not be acceptable for some application 
4. Stock piling facilities are required  , demand for the recyucles must be rouggly matches to supply of concrete waste ( location , time preference , road assess ) .