Producing synthetic lightweight aggregates from reservoir sediments

This paper proposes a procedure to produce lightweight aggregate (LWA) made of fine sediments, which were dredged from the Shihmen Reservoir in the northern Taiwan. The synthetic aggregates were manufactured in a newly developed rotary kiln. Physical and mechanical properties of the synthesized aggregates were subsequently assessed. In addition, engineering properties of the concrete made of the produced aggregates were experimentally measured. The test results show that the sediments containing all necessary materials are expansive as passing through the heated zone in the commercial rotary kiln. The produced aggregates possessed a hard ceramic shell, and a porous core, and a relative density ranging from 1.01 g/cm3 to 1.38 g/cm3, which is significantly lower than normal density of aggregates. The produced aggregates also meet the requirements of ASTM C330 with bulk density less than 880 kg/m3 for light coarse aggregate, and were verified as qualified LWA for structural concrete. Further, the engineering properties of the concrete made from the produced aggregates comply with the requirements of structural lightweight concrete.