Mechanical properties and durability of concrete made with high-volume flyash blended cements using a coarse fly ash

This paper presents a study on the mechanical properties and durability of concrete made with a high-volume fly ash (HVFA) blended cement using a coar se fly ash that does not meet the fineness requirement of ASTM C 618. The r esults were compared with those of the HVFA concrete in which unground fly ash had been added at the concrete mixer. The properties of the fresh concr ete determined included the slump, air content, slump loss, stability of ai r content, bleeding, and setting time, those of the hardened concrete inves tigated included the compressive strength, flexural- and splitting-tensile strengths, Young's modulus of elasticity, drying shrinkage, resistance to a brasion, chloride-ion penetration, freezing and thawing cycling, and to dei cing salt scaling, The results show that except for the resistance of the c oncrete to the deicing salt scaling, the mechanical properties and the dura bility of concrete made with this blended cement were superior to the concr ete in which the unground fly ash and the cement had been added separately at the mixer. The production of HVFA blended cements, therefore, offers an effective way for the utilization of coarse fly ashes that do not otherwise meet the fineness requirements of ASTM C 618. (C) 2001 Elsevier Science Lt d. All rights reserved.