Abstract
Ground treated ultrafine-POFA obtained from palm oil industry was heat-treated to remove excess carbon. The varied proportion (17%, 30% and 40%) of UPOFA was incorporated into the ultra-high strength concrete (UHSC) to study its effects on the UPOFA-UHSC (U-x-UHSC) in comparison with OPC-UHSC (U-0-UHSC) engineering and transport properties. The U-x-UHSC has an increasing workability tendency with a retarded setting times as compared to U-0-UHSC. Besides, U-x-UHSC registered higher compressive strength than the U-0-UHSC. The 90-d strength of 156 MPa was achieved in U-17-UHSC which was 4.7%, 7.5% and 12.2% higher than the values obtained for U-30-UHSC, U-40-UHSC and U-0-UHSC, respectively. The U-40-UHSC exhibited the greatest improvement at 90 days in transport properties such as porosity, water absorption, initial surface absorption, rapid chloride permeability, gas permeability and water permeability while the highest strength was recorded with U-17-UHSC. Thus, the pozzolanic UPOFA is capable of improving the engineering and transport properties of UHSC.