Performance of Cement-Lime-Phosphogypsum Solidified Red Mud as Road Base Material
We conducted indoor experimental research to evaluate the unconfined compressive strength,splitting strength,resilient modulus,and dry-wet and freeze-thaw durability of phosphogypsum-activated cement-lime solidi-fied red mud for road applications.The aim was to investigate the feasibility of using this solidified red mud as a road base material.The experimental results demonstrate that the best road base performance is achieved when the curing agent mixing ratio is mcement∶mlime∶mphosphogypsum=8∶2∶2.The 7-day unconfined compressive strength rea-ches 4.18 MPa,meeting the strength requirements of road base.The splitting strength and resilient modulus at 28-day age are 0.256 MPa and 1 020 MPa,respectively.After five cycles of dry-wet and freeze-thaw,the mass change rate is less than 2％,and the strength loss index(BDR)exceeds 80％.Microscopic analysis using a mercury intru-sion test reveals that the AFt(ettringite)generated from the reaction of phosphogypsum could enhance the strength of red mud by filling pores(0.1～1 μm)in the solidified red mud.However,excessive AFt causes volumetric ex-pansion and gives rise to micro-crack pores(1～10 μm),resulting in deteriorated strength performance.In conclu-sion,the performance test results indicate that the solidified red mud prepared with a ratio of mredmud∶mcement∶mlime∶mphosphogypsum=100∶8∶2∶2 can be effectively used as a substitute for traditional pavement base materials.This discovery provides a broader avenue for the comprehensive utilization of red mud.
red mudroad engineeringroad baseunconfined compressive strengthroad performance
国家科技期刊平台
NSTL
万方数据
维普
