Recycling Application of the Construction Waste in Silt Subbase: A Case Study

With the urbanization process, enormous construction wastes (CW) are produced, which were usually disposed in landfill in the past, resulting in waste of resources and appropriation of land. To recycle CW, this investigation aims to treat CW as the subbase materials instead of traditional backfill in embankment engineering. To achieve this objective, CW was first crushed into appropriate size, then mixed with silt and cement referring the field procedure to prepare the samples with various CW proportions (CWP). Hereafter, basic performances including compactability, unconfined compression shearing strength, California Bearing Ratio were conducted. Results show that the engineering behaviour of silt soils is significantly improved by the CW incorporation. The maximum dry density of the mixture increases with of the CWP, and the largest maximum dry density is obtained when CWP is 50%. UCS and CBR at the maximum dry density with 50% CWP and after 7-day’s curing is about 6.6 and 10.0 times of compacted silt just treated by cement, suggesting that this mixture can satisfy the requirement of subbase materials.