Fresh and strength properties of self-compacting concrete with different waste materials of cement replacement

This study experimentally evaluates the fresh and hardened properties of self-compacting concrete (SCC) incorporating three sustainable supplementary cementitious materials—wood waste ash (WWA), ceramic waste powder (CWP), and ground-granulated blast-furnace slag (GGBS)—as 20% replacements of ordinary Portland cement (OPC). Four mixes were prepared: a control SCC and three mixes with 20% cement replaced by WWA, CWP, or GGBS. Fresh properties were assessed through slump flow, T₅₀, V-funnel, and L-box tests, while hardened performance was evaluated via 28-day compressive and splitting tensile strengths. All mixes satisfied EFNARC criteria for SCC workability, but the type of waste material strongly influenced flow behavior. Compared with the control (slump flow 772 mm, V-funnel 4.34 s, L-box 0.95), WWA caused the greatest loss of workability (692 mm, 9.81 s, 0.81) due to its high loss-on-ignition and porous texture, CWP produced moderate reductions (724 mm, 8.16 s, 0.87), and GGBS preserved rheology most effectively (747 mm, 6.72 s, 0.91). The 28-day compressive strengths were 66.7 MPa for the control, 39.4 MPa for WWA, 57.7 MPa for CWP, and 62.2 MPa for GGBS, reflecting reductions of 40.9%, 13.5%, and 6.7%, respectively. Splitting tensile strengths showed smaller decreases—4.86 MPa (WWA), 4.94 MPa (CWP), and 4.52 MPa (GGBS)—relative to the control’s 5.23 MPa. The experimental results demonstrate that all three wastes can produce SCC meeting flowability standards, but their influence on strength varies with chemical composition and particle characteristics: WWA significantly lowers compressive capacity, CWP offers a balanced performance with moderate strength retention, and GGBS provides the best mechanical properties.