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

In this study, a new technology for preparation of permeable bricks from non-sintered wrap-shell light-weight 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 (P-f), 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, P-f 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, Oit 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. (C) 2020 Elsevier Ltd. All rights reserved.

Automated summary

A new technology for preparing permeable bricks from dredged sediments was developed in this study, investigating the material mix ratio, compressive strength and water permeability coefficient. The study discussed the effects of water-cement ratio, forming pressure, target porosity, and aggregate size on the performance, as well as explored the water permeability and freeze-thaw damage mechanisms of the bricks. Results showed that the comprehensive performance of fine aggregate permeable brick was satisfactory under certain conditions, and the water permeability coefficient was found to be proportional to connected porosity.