Development of a soil stabilizer for road subgrade based on original phosphogypsum

Abstract

The research used industrial by-products original phosphogypsum (PG) as the main raw material, slag (SG) and Portland cement (PC) as auxiliary materials, and the optimal additive amount was determined according to the compressive strength value of the sample. Comprehensively evaluate the water resistance and volume stability of the samples, and determine the best formula for new roadbed stabilized materials. The results showed that when the weight ratio of PG, slag and cement was OPG:SG:PC = 6:3:1, and mixed with 5% micro silica fume (MSF) and 3‰ hydroxypropyl methyl cellulose (HPMC), the sample’s comprehensive performance was the best, specifically, the sample’s compressive strength in 60 days reached 28.8 MPa, the softening coefficient reached 0.9, and the expansion rate was stable at about −0.2%. In addition, the mechanism of action of enhancers MSF and HPMC was analyzed according to use Vicat device, X-ray diffractometer and scanning electron microscope. The best formula SP3GH3 has the best curing effect on soil. The 28-day unconfined compressive strength (UCS) of the sample reached 2.4 MPa, the expansion rate was less than 0.09%, and the water stability coefficient was above 0.79, which was higher than that of the samples cured by traditional cement and lime during the same period.