Effects of freeze-thaw action and composition on compression strength of WFS-FA-EPS fills

Abstract

A frost-resistant earth fill was proposed by mixing waste foundry sand (WFS), fly ash (FA), expandable polystyrene (EPS) beads, Portland cement and water in proportions, which was known as WFS-FA-EPS fill. This study examined the unconfined compressive strength (UCS) weakening susceptibility of a range of WFS-FA-EPS specimens prepared at designated compositions which were exposed to freeze-thaw (F-T) cycling from 20 ºC to −15 ºC and up to 5 times. It was found that the inclusion of EPS reduced the unit weight of the fill materials by 20-40%. The majority of UCS loss was found suffered in the first F-T impact. Cement component clearly enhanced the anti-frost capability of materials. Components of EPS and FA also improved the F-T resistance of materials. Water was the main factor leading to F-T impairment, and should be prudentially added into the mixture. Inclusion of EPS beads was able to mitigate the frost impact by the means of reducing UCS loss. The optimal contents were 1.08% for EPS bead and 30% for FA.