Bentonite is buffer/backfill material needed in high level waste engineering barrier

and the high plasticity of bentonite affects the quality of buffer/backfill block. In a process of adding water for sample preparation

soil agglomeration and uneven distribution of water content affect the quality of blocks. Compared with traditional spray water method

this experiment explored a new water adding technic

mixing ice powder with bentonite powder (shortly the ice-soil mixing method). Water content is controlled between 5%-30%. In order to evaluate the ice-soil mixing method

the mixing efficiency

mass loss rate

the deviation between actual water content and target water content

the relationship between water content and agglomerated particle size

distribution and contents of agglomerate are measured. Besides

microwave-assisted thawing method is proposed to decrease thawing time. The results show that compared with spray water method

the ice-soil mixed method is less time consuming

less causing adhere to the container

and less causing water content deviate to targets. Moreover

the size and percentage of agglomerate in mixture are also decreased obviously; and water content distribution is more homogeneous; furthermore

microwave-assisted thaw method can significantly accelerate the thawing rate without affecting the amount of agglomerates and water content of specimens. This research provides a reference for the production of buffer/backfill material for High Level Waste (HLW) disposal

and can also be referenced by water content adjustment of other cohesive soil.