(cest2017_01028) Alternative calcium-based chemical stabilisers for ground improvement: Paper Sludge Ash treatment of London Clay

摘要

Due to the recent focus on promoting sustainableconstruction practices, chemical ground improvement ofproblematic soils for construction has been increasinglyused worldwide. However conventional soil stabiliserssuch as cement or lime still suffer from the use of nonrenewablenatural resources, high energy consumption andCO_2 emissions for their production. Consequentlyalternative stabilisers are intensively sought;;these wouldbe linked to lower or even zero CO_2 emissions if thesecome from waste. The paper studies the effect of wastepaper sludge ash (PSA) as an alternative to lime for thetreatment of London clay (a moderately expansive soil).The effectiveness of the treatment is assessed comparing anumber of PSA-treated soil properties (plasticitycharacteristics, unconfined compressive strength andstiffness) to those of the same soil treated with lime. Inmost cases the PSA-treated soil specimens are shown tohave a better performance than the lime-treated ones. Thefindings on the macroscopic properties are complementedby microstructural analysis.