Environmental-friendly non-sintered permeable bricks: Preparation from wrap-shell lightweight aggregates of dredged sediments and its performance

Abstract In this study, a new technology for preparation of permeable bricks from non-sintered wrap-shell lightweight aggregates (WSLAs) of dredged sediments was developed. The volume method was used to calculate the material mix ratio. The effects of water-cement ratio (W/C), forming pressure (Pf), target porosity (P) and size of aggregate particles on the compressive strength and water permeability coefficient of dredged sediment permeable bricks (DSPB) were discussed. Furthermore, the mechanism of water permeability of DSPB was deeply explored. The mass loss rate and strength loss rate of DSPB after 25 freeze–thaw cycles were compared with that of the crushed stone permeable bricks (CSAPB), the commercial sintered clay permeable bricks (SCLPB), and the commercial sintered ceramic permeable bricks (SCEPB) prepared by the same process. The damage mechanism of DSPB caused by the freeze–thaw cycles was analyzed. Results showed that when W/C was 0.34, Pf was 3 MPa, and P was 15%, the comprehensive performance of fine aggregate permeable brick (DSPB-F) was satisfactory. It was found that the water permeability coefficient of DSPB is almost proportional to the connected porosity. After 25 freeze–thaw cycles, interestingly, 0it was found that the freezing resistance of DSPB is closely related to the number, width and development trend of micro-pores and cracks at the junctions of WSLAs.