The Dosage of Superplasticizer in Cemented Coal Waste Backfill Material Based on Response Surface Methodology

Abstract

Cemented coal waste backfill material (CCWBM) is developed for backfilling the goaf in coal mines. As fresh CCWBM slurry is generally transported into underground openings through a pipeline, the fluidity of fresh slurry becomes one of the most important properties. Adding superplasticizer is considered to improve the flow performance of the slurry without alerting the mechanical performance of filling body. e dosage of superplasticizer (SP) is related to filling cost, thus response surface methodology (RSM) is adopted to study the influence of material composition on SP when target slump is 250 mm. e effects of fly ash content, fine gangue ratio, and mass concentration on SP are analyzed using the software of Design-Expert and central composite design (CCD), and models are established for SP. Results show that the SP model coincides greatly with the test results and can be applied to analyze and predict SP in CCWBM. Mass concentration, fly ash content, and fine gangue ratio influence SP from high to low. e interaction of fine gangue ratio and mass concentration between SP is the most significant. e fact that the improved aggregate space model can be applied to analyze the fluidity of CCWBM is proved too. e research results provide guidance for the design and preparation of CCWBM with favourable performance and low cost in practical production.

Study on Proportion Optimization of Magnesium Oxychloride Cement-Stabilized Clayey Soil Based on the Response Surface Methodology

“…Te test results became concise and easy to understand. Tis statistical method has been studied in mixed proposition optimization designs [22][23][24][25].…”

Mechanical Properties and Deterioration Instability of Filling Body with Gangue-Cement Material Based on AE Experiment

“…Filling mining is an important part of green mining that can not only solve the problem of "three under" coal pressure in mines but also effectively control surface subsidence [9][10][11]. In view of the filling cost and production conditions, filling materials are required to have the characteristics of wide sources, low cost, and effective filling effect [12,13]. In structural filling mining of coal mines, the gangue-cemented filling material is used to prepare the filling body according to local conditions.…”

“…erefore, Chen et al studied the influence of red mud, chloride, and other materials on the strength of coal gangue-cemented paste filling from a micro point of view based on mechanical experiments and electron microscope scanning [35,36]. Li et al used design expert and central composite design (CCD) software to analyze the effects of fly ash content, fine gangue ratio, mass concentration, and the effects of mass concentration, fly ash content, and fine gangue ratio [12]. erefore, it is very important to accurately grasp the influence of coal gangue and fly ash on the strength of backfill.…”

Effect of Concentration and Suspension Agent (HPMC) on Properties of Coal Gangue and Fly Ash Cemented Filling Material

“…Wang [14] studied the proportion of cemented coal gangue-fly ash backfill mixtures, considering that when the mass ratio of cement fly ash to coal gangue is 1 ‫׃‬ 4 ‫׃‬ 5 and the mass fraction of solid material reaches 72%～75%, the quality indexes of cement slurry such as strength, dehydration rate, and pipeline characteristics can meet the requirements of goaf backfilling. Wu et al [15] carried out an experimental study on the transportability and pressure drop of the CGFB slurry through the loop pipe with the help of a pipe loop system built in laboratory and revealed and discussed the effects of solids concentration as well as ratios of coal gangue to fly ash, fly ash to Portland cement, and coal gangue to Portland cement on the pressure drop of the loop pipe flow of the fresh CGFB slurry samples [11][12][13][14][16][17][18][19][20][21][22].…”