As part of a multiyear study on applications of high strength concrete to the precast, prestressed concrete industry, a laboratory investigation was conducted to determine the effect of various parameters on uniaxial compressive strength. Parameters investigated included mold size, mold material, aggregate type, type of curing, age and specimen end condition. More than 650 specimens for strength evaluation were cast from 10 high strength concrete mixes having 28-day compressive strengths ranging from 9000 to 15,000 psi (62 to 103 MPa). In this study, Type III Portland cement concrete as well as Type III Portland cement concrete incorporating fly ash, microsilica and their combination were used.
