Laboratory experimental study on red mud geopolymer used as road subgrade materials

Lusheng Qin,Chuanchuan Zhang,Xiangxin Jia,Haiqing Zhang,Qingke Nie,M.M.H Mostafa,S Manickam

doi:10.1051/e3sconf/202126102043

Abstract

Red mud is a strong alkaline waste discharged from the process of alumina extraction, which is harmful to the environment and its utilization rate is always low. One of the effective ways to utilize red mud is used as road subgrade material. In this paper, the industrial wastes including red mud, fly ash, slag, and desulfurized gypsum are used as basic raw materials to prepare subgrade filling materials. A series of laboratory tests, such as compaction test, California Bearing Ratio (CBR) test (soaked and non-soaked conditions) and permeability test, are carried out. The physical and mechanical properties, such as maximum dry density, optimum moisture content, CBR value, expansion, permeability coefficient and soaked strength loss rate, of the mixtures with different proportions, were studied. The results can provide reference for the selection of the best proportion scheme and promote the utilization of red mud in subgrade engineering.

Highlights

With the continuous development of China's economy, a large number of industrial solid wastes are produced in industrial production every year
Red mud is a strong alkaline waste residue discharged from alumina production. 1.0 ~ 2.0 t red mud should be produced at the same time for every 1 t alumina production
It can be seen that the maximum dry density of mixed materials is between 1.03-1.51g/cm3, which is relatively small comparing to that of conventional soils, while generally, the maximum dry density of silt, clay and sand is 1.61-1.80g/cm3, 1.58-1.70g/cm3 and 1.80-1.88g/cm3, respectively

Summary

Introduction

With the continuous development of China's economy, a large number of industrial solid wastes are produced in industrial production every year. The amount of red mud is huge, and it is still increasing It takes up a lot of land resources and causes serious pollution to the environment. As a byproduct of the rapid development of flue gas desulfurization industry in thermal power plants, desulfurization gypsum has become another large solid waste in thermal power plants after fly ash. This kind of industrial waste discharge has caused many adverse effects on human production and life, and seriously restricted the sustainable development of ecological environment

Methods

Results

Conclusion