Disclosed is a paste for use in mining processes, such as backfilling and cemented rock fill, to provide improved early and late-stage strength at a lower overall cost. The paste includes mine tailings, one or binding agents, engineering backfill and water. The engineering backfill fibers are typically plastic fibers obtained from plastic products, partially plastic products, recycled plastic products, or partially recycled plastic products. Also disclosed are methods of backfilling a portion of a mine and uses of the paste in mining processes.

A microcapsule of sustainable self-healing coal mine ventilation sealing material crack. The microcapsule includes a microcapsule core material and a microcapsule wall material. The microcapsule core material is prepared using a bacterial lyophilized powder and a substrate. By using urease-producing bacteria, there is provided a method of protecting bacteria to survive a long time in the cement-based material, supplying sufficient nutrient substances and reducing the impact of the doping of bacteria on the mechanical property of the cement-based material. The bacterial lyophilized powder and substrate are prepared into microcapsules which are added into the cement-based material when the cement-based material is mixed. In this case, once concrete cracks, the microcapsules breaks and the spores in the material are activated to perform normal metabolism so as to induce precipitation of calcium carbonate continuously, thereby continuously realizing self-healing of coal mine ventilation sealing material cracks.

Embodiments of a dry mix for producing a concrete composition are provided. The dry mix includes aggregate, cement, and bed ash. The bed ash contains the combustion product of a fluidized bed coal combustion reaction. Additionally, embodiments of a method of preparing the dry mix and embodiments of a method of preparing a concrete composition are provided. The dry mix is also suitable for repairing soil slips, and embodiments of a method of repairing a soil slip are also provided.

A low density annular grout composition for filling voids. The composition may consist of cementitious fly ash, water, set retarder and cellular foam. The composition may have a compressive strength of between 100 and 600 psi at seven days and less than 1500 psi at 28 days. The composition may have a density between 20 and 75 pcf. Also disclosed is a method of filling a void with a low density annular grout composition. The method can include determining the time necessary to fill the void, adding water and set retarder to a cementitious fly ash to make a wet mixture, adding air to the wet mixture, and adding the composition to the void.

High-strength flowable fill compositions are disclosed. The compositions include cement, aggregate (e.g. sand), water, coloring agent, polymer, and fibers. In an embodiment, the compositions include an accelerant, e.g., calcium chloride and/or an air entraining agent. The compositions have a compressive strength of between 10 psi and 500 psi after 1 day, a compressive strength of between 300 psi and 1300 psi after 7 days, and a compressive strength of between 1000 psi and 2500 psi after 28 days.

A composition configured to be mixed with cement, and associated systems and methods are disclosed herein. In some embodiments, the composition includes at least 10% by weight lime particles, and at least 35% by weight pozzolan particles. Properties of the composition can include a magnesium oxide concentration of at least 0.5%, and an iron oxide concentration of at least 0.5-2.0%, an aluminum oxide concentration of 2-8%, a silicon dioxide concentration of 20-40%, a potassium oxide concentration of 20,000-30,000 ppm, and a sodium oxide concentration of 10,000-20,000 ppm. In some embodiments, the lime-based cement extender composition, or product, is combined with cement to produce a cement blend for use in the mining industry as mine backfill.

A fire-resistant two-component mortar system contains a curable aqueous-phase aluminous cement component A and an initiator component B in aqueous-phase for initiating the curing process. Component A further contains at least one blocking agent selected from phosphoric acid, metaphosphoric acid, phosphorous acid and phosphonic acids, at least one plasticizer, and water. Component B contains an initiator, at least one retarder, at least one mineral filler, and water. A fire-resistant two-component system, which is ready-for-use, can be used for a fire-resistant chemical fastening of anchors and post-installed reinforcing bars in mineral surfaces, such as structures made of brickwork, concrete, pervious concrete or natural stone.

Fast-setting flowable fill compositions for filling ground trenches are described. The compositions set quickly but retain a low strength psi at 28 days. The compositions also reduce bleed water on the surface of the fast-setting flowable fill and therefor enable quicker application of surface repair material, e.g., pavement patches, to the trench. The compositions consist of aggregate, Portland cement, accelerant, water and sometimes air. The compositions may have a compressive strength of between 5 psi and 60 psi after 2 hours, a compressive strength of between 10 psi and 100 psi after 4 hours, a compressive strength of between 75 psi and 500 psi after 28 days, a penetration resistance of between 1.5 tsf and 75 tsf after 2 hours, a penetration resistance of between 4.5 tsf and 200 tsf after 4 hours, and a shrinkage of less than 2% as measured by ASTM C490. Also disclosed are methods of filling a trench with fast-setting flowable fill.

The present disclosure relates to a method of cementing comprising: providing a cement composition comprising: water, a cement, and a non-aqueous liquid anti-shrinkage cement additive comprising calcined magnesium oxide and a non-aqueous liquid; introducing the cement composition into a subterranean formation; and allowing the cement composition to set in the subterranean formation. Non-aqueous liquid anti-shrinkage cement additives, cement compositions, and systems are also provided.

The present application discloses various cementitious compositions that incorporate waste materials therein. In some embodiments, the waste materials incorporated in the compositions are mixed construction and demolition fines, including but not limited to small pieces of glass, wood, metal, drywall, cardboard, masonry, and other architectural material and waste materials. Various methods for using said compositions are also disclosed.