Characteristics of Concrete Containing Fly Ash With Hg-Adsorbent

Abstract

The present study has focused on the effects of Powdered Activated Carbon (PAC) in fly ash on the air-entraining admixture demand and consequent properties of concrete. An extensive laboratory test program was completed during this investigation. Three series of mixes were designed to evaluate the effect of PAC as an Hg-adsorbent on the fresh and hardened properties of concrete containing class F fly ash. In addition to concrete with normal volume fly ash (less than 50% replacement by weight of cement), concrete with high volume fly ash was also cast. Fresh properties including the air void content and density were evaluated. Permeable air voids and compressive strength of hardened concrete at four different ages were also measured. Finally, the air void content, specific surface area, spacing factor and shape factor of hardened concrete were determined using the image analysis technique. The results of this study show that the fly ash if injected with PAC in front of the precipitator has insignificant effect on the mechanical properties and air-void network which affect durability (specifically freeze and thaw resistance) of concrete.