Effect of excess dosages of superplasticizer on the properties of highly sustainable high-volume fly ash concrete

AbstractIt is quite common for researchers to use an excess dosage of superplasticizer to achieve the desired very low water to binder (w/b) ratio required for sustainable high-volume fly ash (HVFA) concrete mixes in order to obtain early strength without reporting on the effects of the excess dosage. This study investigates the effects of such excess dosages on the properties of highly sustainable HVFA concrete. Four series of concrete mixes were designed, with Series 0 being the control concrete mix containing no fly ash and no superplasticizer. Series 50, 60 and 65 contained HVFA concrete mixes that had 50, 60 and 65% fly ash content, respectively. Series 50, 60 and 65 contained three similar mixes; in each series, the three mixes were prepared with the maximum dosage of superplasticizer at 2% of the binder by mass, and excess dosages at 3% and 4%, respectively. The effect of the excess doses on slump, flowability, compressive strength, flexural strength, tensile splitting strength, and abrasion resist...