Performance and carbon reduction of binary and ternary concrete systems with slag cement and fly ash

Document Type

Article

Publication Date

7-15-2026

Abstract

Concrete production is a major source of global CO2 emissions due to the use of ordinary Portland cement. This study presents an investigation mechanical and durability properties of low carbon binary and ternary concrete mixtures with incorporating slag cement and Class C or F fly ash. Ten concrete mixtures were designed, including one OPC control, three binary slag mixtures, and six ternary mixtures with total supplementary cementitious material replacement levels of up to 70%. Early age fresh properties, mechanical properties, durability performance, and cradle to gate carbon emissions were evaluated to characterize engineering performance and environmental impact. Binary slag cement mixtures exhibited approximately 15% higher 28-day compressive strength compared with the OPC control, which is attributed to continued slag hydration. Ternary mixtures containing Class C fly ash exhibited comparable compressive strength than the control, with improvements around 5% at 28 days and 11–15% at 180 days due to the higher calcium content and partial self-cementing behavior of Class C fly ash combined with slag hydration. Ternary mixtures incorporating Class F fly ash exhibited slower strength development but showed approximately 25–40% lower drying shrinkage and maintained adequate freeze–thaw durability after 300 cycles. Also, without compromising 180 days compressive strength, replacing approximately 30–70% of OPC with SCMs can reduce embodied carbon emissions by 26–63%. In addition, a Random Forest (RF) model was developed to predict compressive strength in high SCM systems. After transfer learning with the experimental dataset, the model achieved a coefficient of determination (R2) of 0.961 and a root mean square error of 1.87 MPa. The experimental and computational results demonstrate that mixture containing 50% OPC, 30% slag cement, and 20% Class C fly ash provided the best overall balance between mechanical performance, durability, and carbon reduction, delivering approximately 11% higher 180-day strength than the OPC control, while reducing drying shrinkage by 20–35% and lowering embodied carbon emissions by 45%.

Publication Title

Journal of Building Engineering

Link to Full Text

Share

COinS