Carbon uptake capacity in glass powder-modified concrete for masonry blocks

This study aims to quantify the CO 2 absorption due to natural carbonation in concretes used for masonry block production, with the replacement of 20% of Portland cement with glass powder, through thermogravimetric analysis. Cylindrical samples (50 × 100 mm) were produced to evaluate compressive strength and measure carbonation depth (after spraying a pH indicator). Concrete with 20% glass powder reached the highest carbonation depth in the shortest time, with 9.37 mm in 28 days. Regarding compressive strength, both concretes presented similar results, with the matrix with incorporated glass powder achieving, at 28 days of age, a performance 153.20% higher than the minimum regulatory requirement [1] at the age of 28 days. The thermogravimetric analysis revealed that the reference concrete captured 43.33 kg.CO 2 /m 3 , absorbing around 54.5% of the CO 2 emissions associated with cement production, a value similar to that found for concrete with glass powder (55.4%). This study demonstrates that the incorporation of up to 20% glass powder enables CO 2 fixation without compromising mechanical performance.