Precast, Prestressed Concrete Made with Alternative Supplementary Cementitious Materials

Abstract

Supplementary cementitious materials (SCMs) can often be used as a partial replacement of portland cement to produce an environmentally friendly concrete. Alternative SCMs considered in this research first included ground limestone, natural pozzolans, and ground glass pozzolan. This research investigated the feasibility of including alternative SCMs in the production of precast, prestressed concrete. Primary requirements of the precast process included self-consolidating flow and a minimum compressive strength of 3500 psi after 16 hours of curing. A concrete mixture containing Type III portland cement and 30% ground limestone was used to produce 18-foot precast, prestressed beams and their mechanical and structural performance were assessed. Flow, compressive strength, modulus of elasticity, modulus of rupture, flexural strength, and bond strength were measured. Structural performance was found to be similar to that predicted in ACI 318, and the flow and 16-hour strength requirements of the precast plant were easily met.