A washout container to which are mounted inclined ramps that allow a transit mixer, concrete pumping truck or other concrete handling vehicle to drive up over a portion of the container for dumping excess concrete and washing out waste concrete. The container cross-section may be rectangular to semi-circular, and is preferably fabricated with a steel structure. A watertight latching door assembly is coupled to the container to prevent leakage of collected liquid concrete waste material while allowing solidified concrete materials to be unloaded at a disposal site. The interior of the container is preferably lined with a material to which concrete will not adhere. The liner may be applied as a coating to the interior of the container or as a solid material retained within the container. In this way, solidified waste concrete can be easily removed from the container at the disposal site and preferably crushed for recycling.