A low rebound early high strength wet shotcrete and its application

Abstract

The invention relates to the field of building materials, in particular to a low-rebound early-high-strength wet shotcrete and its application, comprising the following raw materials in parts by weight: 380-500 parts of cement, 800-1000 parts of sand, 650-800 parts of crushed stone, 10-30 parts of quick-setting agent, 160-200 parts of water, 20-30 parts of high-strength ultrafine admixture, 40-50 parts of fly ash, the low-rebound early high-strength wet sprayed concrete prepared by the present invention greatly improves the bonding The strength of the concrete is reduced, and the concrete can be sprayed normally in the water-rich area. The result has reached the domestic leading level. The invention can be directly applied to the initial support construction of the tunnel, opening up a new technical approach for the initial support construction of the tunnel.

Description

technical field [0001] The invention relates to the field of building materials, in particular to low-rebound early-high-strength wet shotcrete and its application. Background technique [0002] Shotcrete is the most important force-bearing structure for primary support. Its early strength (within 24 hours), cohesive force, slump retention, and workability have a great impact on the safety, quality, cost, and work efficiency of tunnel construction. Later strength and durability are of great significance to the quality of tunnel operation. According to the status quo of domestic tunnel construction and the "Regulations on the Administration of Quality and Safety Red Lines of Railway Construction Projects", the strength of shotcrete core sampling and testing for the initial support of tunnels in various industries has become the norm. The consumption rate is generally 250% to 300% of the design volume, the excess consumption rate is 150% to 200%, the consumption rate in the w...

AI Technical Summary

Problems solved by technology

However, due to the late start of wet spraying concrete in my country, the low technical level, and the poor quality of domestic raw materials, the non-alkali accelerator and the immature technology of wet spraying manipulators, the sprayed concrete has high comprehensive costs, poor workability, and poor slump retention. The dependence on hand and wet spraying machines is high, sprayed concrete has been at a low level from design to construction, and the development of tunnel technology is facing a huge technical bottleneck

[0003] With the continuous improvement of domestic machinery manufacturing capabilities, large-scale manipulators have been popularized and widely used, and the cost performance of wet-spraying manipulators has continued to increase. However, due to the immature technology of domestic equipment and the fierce competition of homogeneous products, the equipment performance has not made a qualitative leap after all. There is an urgent need for a fundamental breakthrough in the shotcrete mix ratio technology. Only by improving the performance of the concrete itself and reducing the requirements for shotcrete on equipment and personnel can the real needs of tunnel construction be met.

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