Document Type : Research Article
M.S. Student, Civil Engineering department, Qom University of Technology.
The accumulation of coal waste from industry has made these materials available and economical to use in ground improvement reducing environmental pollution. Research has shown that adding cement to coal reduces coal pollution. Therefore, coal tailings of different sizes can be mixed with cement and the resulting mixture can be used to stabilize and improve sandy soil in road construction or construction of stone columns. The main idea of this study is to investigate the effect of particle size of coal tailings and coal leachate on fine sand stabilization with cement. Therefore, different weight percentages of cement and coal tailings of different sizes have been mixed and the physical and strength characteristics of the resulting mixtures have been investigated with several tests such as standard Proctor compaction and unconfined compression tests. To achieve the optimal mixing ratio, the effect of the weight ratio of cement to coal tailings (0/100, 10/90, 20/80, 30/70, 40/60, 50/50) and the effect of the particle size of coal tailings including passing Sieve No. 40, Sieve No. 200, as well as coal waste solution were examined. The results show an improvement in the strength of soils mixed with finer particles of coal tailings. The results of unconfined compression tests show that by increasing the ratio of additives from 2.5% to 7.5%, the compressive strength increases and the optimal mixing ratio of additives is equal to 90% of cement and 10% of fine coal waste particles.