Effects of autoclaved aerated concrete powder admixture on compaction and shear strength characteristics of wet filter cakes

Autoclaved aerated concrete powder (AACP) is a kind of solid waste, which is characterized by strong water absorption ability and low compressive strength. In this work, it is used as the admixture to enhance the engineering performance of wet filter cakes. The compaction behaviors and shear strength characteristics of the filter cakes stabilized with different AACP content were studied. Test results were further compared to those of brick-concrete demolition waste (BCDW)/filter cake mixtures. Changes in permeability coefficient, CBR value and pore structure of compacted samples before and after AACP amendment were also tested. The test results indicated that with the addition of AACP, the permeability coefficient, CBR value and the optimum water content of the compacted samples increased, while their maximum dry density decreased. The AACP/filter cake mixtures exhibited comparable shear strength to those of BCDW/filter cake mixtures under the same compaction degree. From the perspective of compaction effect, the suitable content of AACP in the mixture ranged from 37.2 to 55.3%. Changes in the soil fabric, as determined from MIP test and SEM analysis, agreed well with the changes in their geotechnical properties. These experimental results provide technical references for utilization of AACP and filter cakes in road embankment.