Influence of different W/C on the performances and hydration progress of dual liquid high water backfilling material

Sulfoaluminate cement-based high-water materials are widely used in coal and metal mining. There are few reports on the water cement ratio (W/C) affecting the properties and progress of hydration on dual liquid cement-based materials. Here, the effects of different W/C on dual liquid cement-based material on setting time, viscosity, compressive strength, water loss rate, diffusion radius, hydration heat, Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction and SEM tests were studied. The results showed that as the W/C increased, the setting time increased, and the viscosity of single slurry decreased. Furthermore, as the slurry X and Y were mixed, the viscosity had an inflection point, and the compressive strength decreased while the later strength slowly increased; the relative water loss rate within 60 min reached 2.3-2.6, and was essentially stable after 40 h when the water cement ratio increased from 5:1, 6:1, 7:1, 8:1 to 9:1. When W/C = 8:1, it can be considered a turning point; the formula of diffusion radius obtained by experiments showed that the accumulative heat release and heat flow rate obviously decreased when the W/C was greater than 8:1. Also, the analysis results of XRD and SEM indicated that ettringite was the main hydration product, and as the W/C decreased, its density and shape also changed. (C) 2018 Elsevier Ltd. All rights reserved.