Subventions et des contributions :

Subvention ou bourse octroyée s'appliquant à plus d'un exercice financier (2017-2018 à 2018-2019).

Hydraulic excavators are increasingly being used for excavations needed for repair or replacement of buriedx000D
infrastructure, such as water mains, sewers, communication cables, etc. Because of their high water content,x000D
hydraulic excavation spoils have a sludge-like consistency and can neither be disposed off as solid waste norx000D
recycled nor reused as a backfill. The disposal problem can be addressed by adding super-absorbent polymersx000D
(SAPs) to the spoils. SAPs can absorb several hundred times their own mass in water, thereby providingx000D
"instant" solidification of the spoils and facilitating their disposal as solid waste. Provision of SAP-basedx000D
solidification solutions to a broad range of applications, including spoils from hydraulic as well as traditionalx000D
excavations and tunnelling, is one of the core businesses of the industry partner MetaFLO. MetaFLO's clientsx000D
are looking for ways of using SAP-solidified spoils as a backfill material for post-repair closure of excavations.x000D
Presently, SAP-solidified spoils cannot be used to backfill excavations because of lack of information on theirx000D
expected geotechnical properties and must be transported and disposed at solid waste disposal sites. A keyx000D
objective of the proposed project is to identify the threshold inherent water content of the spoils above whichx000D
the use of SAPs to solidify the spoils will not result in a fill that is of sufficient stiffness and strength to permitx000D
its use as a fill or a backfill. The project will also explore mixing of natural soils with the SAP-solidified spoilsx000D
to enhance stiffness and strength of the spoils. The overarching goal of the project is to develop guidelines forx000D
the use of SAPs, which can be used by contractors to establish the relative proportions of spoils, SAPs, andx000D
natural soils to achieve desirable geotechnical properties of the resulting mix based on the measured inherentx000D
water content of the spoils. A comprehensive lab testing program that uses the state-of-the-art geotechnical labx000D
testing facilities at York is proposed in which combinations of clay slurries prepared at different waterx000D
contents, two types of SAPs, and general-purpose Portland cement as binding agent are used to ascertainx000D
Atterberg limits, stiffness, strength, compaction, and hydraulic flow properties of the resulting mixes.