The effect of fly ash, β-cyclodextrin and fly ash-β-cyclodextrin composites on concrete workability and strength

To increase the use of fly ash (FA) as a pozzolanic material in concrete, a composite was formed with an interaction of FA with β-cyclodextrin (β-CD). Further research was carried out in this article to study the effects of replacing cement with FA (30% and 50% by mass), β-CD (0.025%, 0.05% and 0.1%) and FA-β-CD composite on the workability and strength of concrete. Workability was assessed by means of the slump test and strengths were assessed using the compressive and split tensile strength tests. Higher combined contents of FA and β-CD resulted in increased workability of concrete of up to approximately 550%. Furthermore, the inclusion of β-CD generally increased both the compressive and tensile strengths of the concretes not containing FA by up to 10%. When combined with FA, the β-CD resulted in increased compressive strengths of up to 63% and tensile strengths of up to 28%, compared to the relevant pozzolanic concretes which did not include β-CD. The study contributed to the knowledge of FA performance using cyclodextrin and promoted the continued inclusion of FA in concrete, which in turn should reduce the environmental pollution resulting from FA.