Mechanical properties of self-compacting high-performance concrete with fly ash and silica fume

Abstract

This paper presents the results of experimental work on the mechanical properties of self-compacting high-performance concrete (SCHPC) containing fly ash (FA) and silica fume (SF). The paper focused on the feasibility of substituting the ordinary Portland cement with waste supplementary cementing materials to decrease the abundant disposal of FA likewise improving the mechanical properties of SCHPC. Six (6) different mixes were made with 0%, 25%, 40%, 50%, 60% and 75% cement replacement by FA and SF. Test on fresh concrete such as Slump flow, L-Box, and V-funnel was conducted to assess the fresh properties of SCHPC. The mechanical properties evaluated were development of compressive strength, splitting tensile strength and static modulus of elasticity. The results of slump flow, passing ability, and viscosity indicate that it satisfied the requirement of the Specification and Guidelines for Self-Compacting Concrete. Maximum compressive strength of 79.73 MPa was obtained by 25% PC; 65% FA; 10% SF at 28 days and the cement content of this mixture is only 146.88 kg/m3. The splitting tensile strength of SCHPC at the age of 28 days increases from 4.84 to 5.86 MPa, while the static modulus of elasticity values ranges between 64,685 MPa to 86,676 MPa. The results indicated that there is a synergy between FA and SF that can provide good alternative to produce SCHPC with smaller cement content and improved mechanical properties.