University of South Africa, South Africa
Bolanle Deborah Ikotun is a researcher and a Senior lecturer in Civil Engineering department, University of South Africa. She has DIng (waiting graduation), MSc (Eng) and B.Eng degrees in Civil Engineering from the University of Johannesburg, University of the Witwatersrand, South Africa and The Federal University of Technology Akure, Nigeria respectively. Her research interests are in concrete mix design, concrete structural and durability properties testing, chemical deterioration of concrete, mechanical testing of concrete, concrete quality optimization techniques and investigation of extenders as they affect mortar and concrete properties. She has authored and co-authored articles in peer-reviewed conference proceedings and reputable journals. She has served as a reviewer for reputable journals and presently supervising postgraduate students.
This study looked into the possibility of increasing the utilisation of fly ash (FA) in concrete technology. FA, being an industrial waste that is in abundance in South Africa and a source of environmental pollution is presently being used minimally in the construction industry. The study on its interaction with cyclodextrin (an enzymatic modification of starch) for possible increased usage in concrete operations was done. Different South African fly ashes were characterised and their compatibility with cyclodextrin to form a useful composite was studied by XRD, SEM and FT-IR. Composite samples were synthesized following two different procedures. Since these are novel composites, indicative tests were performed on strength (compressive and split tensile) and durability (oxygen permeability, sorptivity and porosity) on mortar/concrete made with FA (30% of cement by mass) and fly ash-β-cyclodextrin (FA-β-CD) composite, that further guided the research. Based on the indicative tests results, a possible optimum composite synthesis method and percentages of β-cyclodextrin (β-CD) in the mixtures were identified. These optimal parameters were used to study the effect of FA, β-CD and (FA-β-CD) composite on cement paste hydration (XRD, SEM and FT-IR), rheology (viscosity and setting time), concrete strength (compressive and split tensile) and concrete durability (oxygen permeability, sorptivity, porosity and chloride conductivity). In general, concrete’s hydration products were modified with FA–cyclodextrin composite, which boosted the performance of FA in concrete. The composite improved FA concrete’s early compressive strength, permeability, sorptivity, porosity and chloride conductivity.