Abigroup Contractors turned to BCP, to manufacture the precast concrete slabs used to strengthen the tunnel. This project presented some unique difficulties, as not only did BCP need to manufacture product to comply with the contractor's programme, but also needed to comply with the requirements of Sydney Airport Corporation Limited (SACL) that specified that all deliveries and onsite work to be carried out in the dead of night during Sydney Airport's takeoff and landing curfew.