A comparative assessment of strength and fracture performance of alccofine and fly ash blended high performance concrete

Abstract

The present study compares fracture behavior of high strength concrete (HSC) developed with high calcium fly ash (FC) and Alccofine (AL) as mineral admixtures. For the HSC mixes developed, proportion of mineral admixtures is maintained at 20% of ordinary Portland cement (OPC) whereas the water binder ratio is maintained at 0.26. The dosage of chemical admixture at 2% is adopted to achieve flow values in the range of 150–200 mm. The compressive strength at 7 and 28 days for blended mixes of FC (i.e., FC-HSC) and AL (i.e., AL-HSC) is compared with the control specimen strength. The observed results suggest comparable compressive strength for AL-HSC and FC-HSC. The control specimen strength is lower and was not further explored for fracture studies. The fracture behavior of the blended HSC mixes is then studied by comparing load-CMOD response of FC-HSC and AL-HSC specimens at 28 days. The fracture behavior of AL- HSC exhibits higher peak load and initial stiffness while FC-HSC exhibits higher post-peak ductility. The observed response is further analyzed to evaluate fracture parameters namely stress intensity factor (KIC), fracture energy (GF) and critical crack length (acr). The results indicate higher elastic modulus and KIC for AL-HSC while GF and acr is higher for FC-HSC.