The use of artemisia sphaerocephala Krasch. gum as an eco-friendly stabilizer to improve the mechanical properties of disintegrated carbonaceous mudstone

Abstract

Carbonaceous mudstone is widely distributed in many areas. Its disintegrated material has attracted great interest as a low-cost embankment filler. However, the poor mechanical properties of the disintegrated carbonaceous mudstone (DCM) prevent its widespread application. In this paper, we report the use of artemisia sphaerocephala Krasch. gum (ASK gum) to improve the mechanical properties of DCM. A series of DCM/ASK gum mixtures containing 0 to 8% ASK gum have been prepared and examined by direct shear, unconfined compressive strength, dry-wet cycle, and permeability tests. When 4% ASK gum is incorporated, the unconfined compressive strength of the mixture cured at a duration of 14 days increases by 380%. After 8 dry-wet cycles, the strength of the DCM/ASK gum mixture is 6.4 MPa, which is 12.8 times higher than that of untreated DCM, and the strength retention rate is 61.5% compared to that of 45.5% for untreated DCM. When the normal pressure is 100 kPa, the shear strength increases by 50.0%. In addition, the permeability coefficient was reduced to only 15.9% at 96% compaction degree when only 1% ASK gum is introduced. Scanning electron microscope measurements disclose that the ASK gum can cross-link the DCM particles to form a compact and flat structure, which explains the improved mechanical properties. As both DCM and ASK are abundant, low-cost, and environmentally friendly, the mixture with substantially improved mechanical properties can be a very promising filling material for embankment application.