A feasibility assessment of low-carbon concrete containing calcined clay and granite powder or dolomitic limestone in Burkina Faso

Abstract

The development of low-carbon concrete (LCC) is crucial for reducing the large carbon footprint of the construction sector, in countries like Burkina Faso where there is a lack of high-purity limestone to produce clinker, resulting in the importation of clinker, which exists in dolomitic limestone form. This study assesses the feasibility of producing such LCC in Burkina Faso by utilizing local resources. It designs a class C25/30 concrete, containing 330 kg of cement per m3, where ordinary Portland cement was partially replaced (up to 50%) with a mix of calcined metakaolin clay (30%) and granite powder or dolomitic limestone (10–20%). Results show that the synergy between metakaolin and granite powder significantly improves performance. The optimal mixture, 60C30M10G, achieved a 28-day compressive strength of 35 MPa, representing a 35% increase over the reference concrete, while also enhancing tensile strength and resistance to acid attack and water absorption. This is due to a densified microstructure resulting from pozzolanic reactions and filler effects. Furthermore, the 50C30M20G design reduced CO₂ emissions by 30% while still meeting the target strength class. In contrast, dolomitic limestone provided a modest improvement. This study confirms the potential for high-performance, low-carbon concrete adapted for the West African context, aligning the circular economy with sustainable infrastructure development.