4 results about "Initial strength" patented technology

The present application belongs to the technical field of geotechnical engineering support, and discloses a self-drilling anchor rod supporting system and method based on adjustable delayed expansion slurry and dynamic pressure splitting grouting cooperation. The present application forms a coated calcium oxide expanding agent by using a specific material, and delays the expansion burst time to after the slurry has initial strength and the orifice is locked. The limited expansion force not only compensates for the condensation of the cement base, but also is converted into a powerful radial compressive stress, which realizes "first extrusion and compaction, then cementation and solidification" for the broken surrounding rock, and greatly improves the overall stability of the composite bearing body. The dynamic pressure splitting grouting process of introducing a specific frequency pressure is used to open the crack tip and communicate other cracks by using alternating pressure. At the same time, the hydrophobic coating of the coated calcium oxide expanding agent physically isolates the core expansion component during the grouting stage, avoiding the viscosity surge and invalid expansion caused by the premature hydration of conventional expanding agents. The two cooperate to ensure the excellent permeability and uniform diffusion capacity of the slurry in the deep micro blind end cracks.

Provided is a cement composition which contains a blast-furnace-slag fine powder and, despite this, is less apt to crack, does not have a large increase in temperature due to hydration reaction, and shows an excellent initial strength development.　The cement composition comprises portland cement, a blast-furnace-slag fine powder, and fly ash, wherein the blast-furnace-slag fine powder satisfies all of the following requirements (1) to (3) and the proportions of the portland cement, the blast-furnace-slag fine powder, and the fly ash are 25-45 mass%, 35-65 mass%, and 10-20 mass%, respectively, relative to a total of 100 mass% of the portland cement, blast-furnace-slag fine powder, and fly ash. Requirement (1): The blast-furnace-slag fine powder has a Blaine specific surface area of 4,100-4,500 cm2 / g. Requirement (2): The blast-furnace-slag fine powder has a basicity of 1.80-2.00. Requirement (3): The blast-furnace-slag fine powder has an MgO content of 3.0-6.0 mass% and an SO3 content of 1.5-2.5 mass%.

The application provides a back-embedded device and method for supporting a water-rich stratum segment, relates to the field of tunnel engineering, and aims at the problem of poor adhesion of a support member arranged between a segment and surrounding rock. Under the action of a shear member, the initial strength is improved, under the stable action of a support layer, water seepage into the shell can be evenly diffused by the fiber cotton, the expansive cement is uniformly expanded, small gaps are filled, and thus the adhesion effect of the segment and the surrounding rock is ensured, and the support strength on the segment is improved.