 This study investigated the use of local fly ash from Colombia for the production of ultra-high performance concrete, UHPC. A numerical optimization process was employed to determine the optimal mix ratio for the desired properties of flow and compressive strength. The results indicated that the use of local fly ash could result in compressive strengths of up to 150 MPa without any heat treatment. This article was authored by Joaquina Belengarcia, Nancy Torres-Castellanos, Jamie Antonio Fernandez-Gomez and others.