Evaluation of physicochemical properties and environmental impact of environmentally amicable Portland cement/metakaolin bricks exposed to humid or CO2 curing condition

The present study investigated evaluation of physicochemical properties and environmental impact of environmentally amicable Portland cement/metakaolin bricks exposed to humid or CO2 curing condition. Portland cement was replaced with metakaolin at various dosages (0, 10, 20, 30, and 40 wt%) and the brick samples were subjected to different curing regimes (e.g., air, humidity, and CO2 curing). Analytical assessments of the compressive strength and water capillary absorption as well as pH measurements, X-ray diffractometry, and thermogravimetry were performed. Moreover, a carbon footprint based on CO2 uptake results was evaluated to calculate the environmental impact reduction by the CO2 curing process. The test results indicated that the CO2 uptake of the CO2-cured paste samples was enhanced upon the incorporation of metakaolin. A carbon footprint assessment of the CO2-cured samples revealed that the final CO2 emission of the bricks and the corresponding environmental impact can both be reduced as the metakaolin dosage is increased. •Physicochemical properties of metakaolin-incorporated Portland cement are investigated.•Brick samples are exposed to humid or CO2 curing condition.•The CO2 uptake of the CO2-cured paste samples is enhanced through the substitution of metakaolin.•CO2 curing and metakaolin substitution can significantly reduce environmental impact.