Rebar corrosion and ASR durability assessment of fly ash concrete mixes using high contents of fine recycled aggregates

Abstract

This research assessed the potential alkali silica reaction (ASR) of fine recycled aggregates (FRA) derived from precast concrete slabs using petrographic examination and expansion tests, the effects of incorporating FRA on some chloride related transport properties and the corrosion risk of fly ash blended concretes. Mixes incorporating 20 % fly ash (FA) were produced using water-to-binder ratios of 0.45 and 0.50 and FRA replacements of 0 %, 20 %, 60 % and 100 % to test concrete’s mechanical performance, chloride penetrability and rebar corrosion risk using electrochemical techniques at different ages. FRA presented an ASR expansion 227 % higher than natural aggregates. Using high contents (>60 %) of FRA didn’t increase corrosion risk and a comparable risk to conventional concrete was observed when incorporating FA.