An extrusion granulation process without sintering for the preparation of aggregates from wet dredged sediment

In order to avoid the energy consumption of dewatering and dust pollution in the preparation of non-sintered lightweight aggregates from dredged sediment, a new low-dust process of preparing non-sintered extruded wrap-shell aggregates (TH-WSLAs-W) by extrusion granulation is proposed and applied to produce TH-WSLAs-W baking-free bricks (TH-WSLAB-W). The basic physical properties (cylinder compressive strength, bulk density and water absorption) and microstructure of TH-WSLAs-W was explored. It shows that the curing agent will form a hydrophobic gel film around the sediment particles and form a network structure, which enhances the cylinder compressive strength (6.7 MPa) and frost resistance of TH-WSLAs-W. In addition, the interfacial transition zone among TH-WSLAB-Ws was studied by scanning electron microscope. It found that the micropore structure endow the TH-WSLAs-W with excellent water absorption and drainage property, promoting the hydration of cement, promising the integration of aggregate and cement, and its compressive strength reaches 20.5 MPa.