Experimental study on red clay paste backfilling material and its physical characteristics

backfilling mining is an important way to realize safe, green mining in mines. However, backfilling materials require a wide range of sources, low cost, and must meet the backfilling effect. Therefore, many researchers and technicians have devoted a lot of energy to research and develop new paste backfilling materials. Based on the engineering background of Guangxi’s Baise Zhoujing Coal Mining, this paper considers replacing fly ash with laterite, which is convenient and low-cost, and mixes it with coal gangue and cementing materials to make laterite paste backfilling materials. By measuring the slump, expansion and bleeding rate of red clay paste backfilling materials with different proportions and different slurry concentrations, and using the RYL-600 shear rheometer to perform uniaxial compression tests, the compressive strength and Modulus of elasticity, analysis of the strength characteristics of red clay paste backfilling materials, and the influence of material ratio and slurry concentration on its performance. From the test data, it is found that compared with the traditional fly ash type backfilling material under the same conditions, the laterite type backfilling material has little difference in strength, and the laterite type has the advantages of low cost, convenient material acquisition and no pollution to the environment. The dry material mass fraction has the greatest impact on the strength of the backfilling, and the performance is optimal when it is 80%;as the content of red clay increases, the strength of the backfilling will decrease, the data shows that the mass ratio of laterite to cement meets the backfilling requirements at 1∶1, 1∶2, 2∶1, and the ratio of gangue∶laterite∶cement = 6∶2∶1, the backfilling material not only meets the requirements of the paste backfilling process, but also reduces the backfilling cost. Using red clay to prepare paste backfilling materials can rationally utilize resources, reduce costs, and provide reference opinions for backfilling mining, which has certain reference value.