Abstract
In order to adapt to dry and wet environment in mine roadways and improve the performance of sealing materials under different environmental conditions, this study selected the materials based on their ability to spray and found that the materials with a viscosity of 1500–6000 MPa·s can achieve a balance between performance of spray and wall‐hanging performance. Next, by selecting high‐elastic polyacrylate emulsion and ordinary Portland cement as the film‐forming agent and gel, respectively, mix proportion factors of the nonreactive thin spray‐on liner (TSL) were analyzed by using the Taguchi method. Moreover, fluidity, setting time, sealing properties, compressive strength, bending strength, and bonding strength of those materials were measured. It was disclosed that addition of an appropriate amount of polyacrylate emulsion can enhance the effects of fibers. By observing the morphologies of the materials’ bonding surfaces and comparing the factors influencing bonding strength between both dry and wet walls, it was uncovered that the adhesive property of cement‐based sealing materials was mainly affected by the water‐cement ratio. Eventually, bonding strength and sealing properties were selected as primary optimization indexes, while setting time, bending strength, and compressive strength were selected as secondary optimization indexes. The appropriate proportions of two types of TSLs for dry and wet walls were (W/C = 50%; P/C = 6%; F/C = 1%; T/C = 0.2%) and (W/C = 45%; P/C = 6%; F/C = 1%; T/C = 0.4%), respectively. A prepared TSL can be used for filling rock fractures in mine roadways. In addition, TSL exhibited a great performance for dry and wet walls under different environmental conditions. The present study may provide an insightful guidance and reference for the investigation of TSL sealing materials applied in the mine roadways.
Highlights
In contrast to traditional methods, thin spray-on liner (TSL)-based sealing technique possesses a series of advantages, mainly including less amount of utilization, favorable filling and enclosing performance, high bonding
TSL materials were first poured into the middle of the mould, and the gaps on the two ends were filled; the mould was placed on the shaking table and shook for compaction, as shown in Figure 2(a); after 24 h, the mould was dismantled for curing
When W/C 40%, the viscosity elevated by 331.8%; when W/C 45%, the viscosity increased by 212.5%; when W/C 50%, the viscosity rose by 201.1%; and when W/ C 55%, the viscosity elevated by 150%. e increase in viscosity when W/C 55% was reduced by 54.8% compared with the condition when W/C 40%
Summary
Anchor networks and concretes were generally used in mine roadways for surface sealing. Anchor networks can only play the role of passive protection and are corroded, accompanied by a great labor intensity in installation. Concrete support liners have a remarkable weight, which can impose safety threats after bonding failure [6,7,8,9,10,11,12]. In contrast to traditional methods, TSL-based sealing technique possesses a series of advantages, mainly including less amount of utilization, favorable filling and enclosing performance, high bonding
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