The civil research groups and several of the undergraduate courses generate concrete based waste. There are two main categories of waste containers outside in the EME central courtyard for their disposal:
Clean concrete waste: Cement, sands, aggregates, regular additives.
Dirty concrete waste: Concrete which contains rebar or unusual contaminants/additives.
There are one to two bins of each type at anytime outside of EME 0256.
If you are unsure of which type of concrete waste you have, you can reach out via the Technical Support Group Ticket System.