Eco-efficient concretes, optimized by Alfred’s packing model, with partial cement replacement by limestone and diabase stone powder

Concretos ecoeficientes, otimizados pelo modelo de empacotamento de Alfred, com substituição parcial do cimento por pó de pedra de calcário e diabásio

Abstract

Cement production contributes to approximately 7% of global CO₂ emissions, prompting the cement industry to adopt various mitigation actions. Consequently, the onus falls on concrete producers to employ more efficient mix design methods that reduce the carbon footprint. Utilizing particle packing models and cement substitute materials holds promise for producing more eco-efficient concretes. In this context, this study compared limestone powder and diabase powder application as partial substitutes for cement, assessing the technical feasibility of using diabase powder. In addition to concretes incorporating these powders, a reference concrete without any substitution was prepared. Mix design methods were determined using Alfred's particle packing model. Analyses were performed by compressive strength, electrical resistivity, modulus of elasticity, as well as environmental parameters such as binder consumption (bi) and CO₂ intensity (ci). Results indicated that the limestone powder concrete exhibited higher resistivity, suggesting a more compact cementitious matrix. Compressive strength data revealed statistically equal values across all concrete types. However, the modulus of elasticity for the powders-based concretes was slightly reduced compared to the reference concrete. Regarding the environmental indicators, concrete with limestone powder showed better performances in both binder consumption (bi) at 3.9 kg/m³/MPa, and CO₂ intensity (ci) at 3.28 kgCO₂e/MPa. These values were below literature benchmarks (10 to 15 kg/m³/MPa for bi and 7.9 to 9.1 kgCO₂e/MPa for ci), indicating the achieved eco-efficiency. The parameters evaluation indicates that Alfred's model and the incorporation of stone powders contribute to the mechanical and environmental efficiency of the studied mixtures.

Keywords:
eco-efficient concrete; particle packing; Alfred’s model; stone powder; sustainability