Selection of the optimal composition of the fill composite with the required viscosity and sufficient mechanical characteristics

Introduction. Previous studies of the backfilling composite mixture and the hardened massif did not take into account the balance between transportability and strength. The choice of the backfilling composite mixture formulation that allows for the necessary transportability and specified strength to be ensured at the same time is an urgent task. Materials and methods. Comparative analysis of mixtures of different formulations was applied using a rotational rheometer. Rheo3000 software displays data from one point to plot a curve. Mechanical properties were investigated on Haizhi press, with a loading rate of 0.5 mm/min. Results. 1. Low solid content backfill composite mixtures have better transportability. 2. Increasing the cement component leads to an increase in the viscosity of the backfill composite solution. 3. An increase in the total volume of solid and binder in the volume of solid provides an increase in strength. Discussion. It is the influence of the solid component together with the binder in it that determines the smaller volume of water, which increases friction between the particles and layers of the mixture and affects transportability. Conclusion. 1. An increase in the proportion of binder leads to a deterioration in transportability. 2. An increase in the total solid component of the mixture negatively affects its mobility. 3. An increase in strength characteristics is observed with an increase in the total proportion of solid or individual binder in its formulation. Resume. 1. The results of the studies of the influence of solid matter and cement component on viscosity and strength indices are presented. 2. The influence of all studied factors on viscosity and strength indices is in good agreement with the exponential function. Suggestions for practical applications. The results useful in choosing the formulation of the backfilling composite that satisfies sufficient transportability and the required strength.