Geotechnical Properties of Cement-Treated Fly Ash-Foundry Sand Mixes

Abstract

Fly Ash (FA) is considered an industrial waste until researchers opted to study its pozzolanic properties, which can have varied applications in the construction industry. The high pozzolanic properties of FA help to promote its multiple applications. Whereas Foundry Sand (FS) is waste generated by metal casting industries, its high silica content can also contribute to the enhancement of the engineering properties of FA. This study reports the geo-engineering properties of FA-FS mixes. Furthermore, the mechanical properties, like unconfined compressive strength (UCS) of cement-treated FA-FS mixes with varying cement content (4% to 16%), are carried out at curing regimes of 0, 7, and 28 days and reported. Results show that the maximum dry density (MDD) of the FA-FS mix increased from 1.3 g/cc to 1.75 g/cc, while the optimum moisture content (OMC) decreased from 24.59% to 16.84% as the FS content in the mix increased from 0 to 50%. The UCS values improved significantly with curing durations. The maximum UCS was recorded as 7.84 MPa. respectively, at an optimal foundry sand replacement of 50% and a cement of 16%.The SEM images show dense gel formation, which supports our findings. The results show that FA-FS mixtures could be a sustainable alternative to traditional materials in geotechnical engineering. The enhanced mechanical performance of these mixtures positions them as a sustainable and viable alternative to conventional materials in various civil engineering applications, particularly for use as subgrade and subbase layers in pavement systems and as structural backfill in geotechnical works.