Preliminary study on preparation of unfired bricks using filter cake from tunnel muck

Abstract

Disposal of tunnel muck is a thorny issue in tunnel construction, which has adverse social, environmental and economic impacts. At present, the gravel, sand and water in the tunnel muck can be reasonably recycled, while filter cake (FC), the clay content in the tunnel muck, is still treated by landfill. In this work, based on a comprehensive test plan with three parameters and five variations for each parameter, FC was initially used to prepare unfired bricks, and the possibility of resource utilization of FC was explored. Furthermore, unconfined compressive strength and water resistance of unfired bricks were systematically investigated. Results showed that the maximum strength of the prepared unfired brick samples could reach 25.7 MPa which achieved the requirements of MU25, and the incorporation of an appropriate amount of waste red brick powder (WRBP) and ionic soil stabilizer (ISS) could significantly improve the unconfined compressive strength and water resistance of unfired bricks. Therefore, FC had great potential to replace clay to prepare unfired bricks instead of being deposited as wastes.