Strength characteristics of phosphogypsum stabilized soil under dry and wet cycles

In order to study the strength characteristics of red clay stabilized by a high dosage of phosphogypsum, a mix proportion design was carried out at the ratio of phosphogypsum:red clay = 1:0.5, 1:1, 1:2, 1:3, 1:4, and 1:5 using 4%, 6%, and 8% cement as a curing agent, and this study was carried out through the unconfined compressive strength test, water stability test, California bearing ratio (CBR) test, and durability test. As the phosphogypsum content increases, the unconfined compressive strength of the mix shows a trend of increasing and then decreasing, the unconfined compressive strength of the mixture is the largest when the ratio is 1:3, and with the increase in the number of dry and wet cycles, the unconfined compressive strength of the mixture decreases, and the decay is the largest at 2–3 dry and wet cycles. The higher the phosphogypsum content, the better the water stability performance of the mix. In addition, the CBR value of the mixture can meet the requirements of freeway, primary highway, secondary highway bed, and embankment filler bearing ratio. In this paper, a mix durability test method is proposed to express the mix durability performance in terms of mass loss rate and durability coefficient; the mass loss rate of the mix increases with the increase in the number of wet and dry cycles, and the durability coefficient decreases with the increase in the number of wet and dry cycles; the higher the content of phosphogypsum, the better the durability performance of the mix.