Undrained behaviour of clay reinforced with surplus carpet fibres

A collaborative research programme between University of Bolton and Bradford University is investigating the effect of surplus carpet fibres on the strength as well as other important geotechnical properties of cohesive soils. Initial work concentrates on the manner in which the fibres affect the quick undrained properties of the reinforced soil. Four different surplus carpet fibre types are being used during the study (most popular in United Kingdom) mainly containing fibres from “top-finishing” and “shredded segments” of carpets. Relatively low plasticity index clay has been prepared using commonly available clay within the North-West Region of the UK. A series of quick undrained (UU) triaxial compression tests is scheduled for 76mm in height by 38mm diameter soil specimens reinforced with target concentrations of 1%, 5%, and 10% of ‘surplus’ carpet fibres (by dry soil mass) compacted at optimum water content for the light (2.5kg) BS1377 method. The mixing efficiency of the surplus carpet fibres within the cohesive soil is of critical importance alongside the methodology for preparing samples to a uniform standard for research purposes. Later stages of the work intend to extend the investigation into effective stress path testing, exploration of practical methods of mixing and compaction in the field for civil engineering applications.