The Impact of Brick Powder Specific Surface Area on Cement Replacement in Mortar Mixes: A Sustainable and Cost-effective Solution for the Construction Industry

This study examined the use of clay brick powder (CBP) as a partial substitute for cement in mortar mixes. Five mixes were tested, each differing by the fineness of the CBP, obtained by grinding brick waste for different durations (30, 60, 90, 120 minutes). Several parameters were evaluated; apparent density, porosity, spread, ultrasonic pulse velocity (UPV), flexural and compressive strength, and the pozzolanic activity index. The results indicate that, when the brick powder is ground for 60 minutes, the spread of the mortar exceeds 95% compared to the reference mortar. The addition of CBP appears to increase the water absorption and porosity of the mortars, without significantly influencing their apparent density. Most samples have a UPV close to 4000m/s, attesting to satisfactory mechanical properties. The use of 20% CBP in replacement of cement leads to a decrease in flexural strength. However, this drop is less when the specific surface area of the CBP is close to that of cement. As for compressive strength, a decrease is also noted with the introduction of CBP, but this decrease can be mitigated by using CBP with a specific surface area similar to that of cement. These factors can significantly influence the pozzolanic activity of the mortar mix. Furthermore, our investigations into environmental and economic analyses show that the use of cement mixes including CBP results in a significant decrease in energy consumption and CO2 emissions. More specifically, the replacement of 20% of cement with CBP of different granulometries has led to promising results.