Utilization of Phosphogypsum as Raw Material for Manufacturing of Non-Fired Load-Bearing Wall Bricks
Non-fired load-bearing wall brick was prepared utilizing non-treated original waste PG as raw material in the laboratory. When the amount of PG and cement is 65% and 10% (by weight) in the brick mixture, respectively, the compressive strength of bricks is still over 23MPa and the flexural strength comes up to 4MPa. Besides, the bricks hold excellent water-resistance and frost-resistance. Effects of steel slag or/and fly ash content on performance of bricks and effects of the change of sand content on water-resistance and frost-resistance are discussed. Results indicate that the compressive strength, flexural strength and soft coefficient are higher when blended mineral additive with various amounts of steel slag and fly ash. The frost-resistance goes up with the increase of the steel slag content, the water-resistance and frost-resistance goes down when the sand content decreases from 15% to 10%, no matter the 5% sand was replaced by fly ash or steel slag as equal weight. Microstructure of brick was investigated by XRD and SEM. Strength of brick results from a large amount of AFt (3CaO•Al2O3•3 CaSO4•32H2O) and C-S-H (calcium silicate hydrate) presented in the matrix which may be viewed as the biggest strength contributors bonding the gypsum and quartz together to a compact matrix.
Hui Li, Yan Feng Liu, Ming Guo, Rui Zhang and Jing Du
L. Yang et al., "Utilization of Phosphogypsum as Raw Material for Manufacturing of Non-Fired Load-Bearing Wall Bricks", Advanced Materials Research, Vols. 374-377, pp. 787-791, 2012