High-ductility cement based composite material and preparation method thereof

Abstract

The invention discloses a high-ductility cement based composite material and a preparation method thereof. The composite material comprises cement, coal ash, clean fine river sand, a rubber powder, fiber, a water reducer, an emulsion powder, a setting accelerator and water according to certain ratio. As the composite material has high breaking energy and ultimate tensile strain, excellent crack resistance, adjustable four-point bending toughness index and reasonable compressive strength, the composite material can be applied to a sprayed concrete material in a coal mine deep mine tunnel supporting structure system, and can be applied to a prayed concrete material of primary supports for mountain tunnels, particularly large deformation tunnels and severe unsymmetrical loading tunnels for railway engineering and highway engineering.

Description

technical field [0001] The invention relates to the technical field of civil engineering materials and their preparation, in particular to a high-ductility cement-based composite material and a preparation method thereof. Background technique [0002] Combined support methods such as anchor net spraying support, anchor net spraying + anchor cable support, anchor net spraying + beam + anchor cable support are generally used in deep coal mine roadways in my country. The shotcrete used in these support methods is composed of cement, coarse and fine aggregate, water, and quick-setting agent. The commonly used spraying methods include dry spraying, tidal spraying and wet spraying. The main disadvantages of this traditional shotcrete are low tensile strength, low ductility, and poor toughness. Uncoupling occurs in the deformation, and the pressure of the surrounding rock cannot be fully relieved, resulting in stress concentration in the local spray layer, which induces premature ...

AI Technical Summary

Problems solved by technology

The main disadvantages of this traditional shotcrete are low tensile strength, low ductility, and poor toughness. Uncoupling occurs in the deformation, and the pressure of the surrounding rock cannot be fully relieved, resulting in stress concentration in the local spray layer, which induces premature cracking and shedding of the spray layer, weakening or even losing the sealing and surface support of the surrounding rock. Cracking or falling off makes the integrity of the support structure lose and cannot form the effect of joint support

Mountain tunnels such as railway engineering and highway engineering, especially tunnels with weak, broken, well-developed joints and severe bias tunnels, have nonlinear large deformation characteristics after excavation. Traditional shotcrete has serious deformation coordination with rock surfaces. Insufficient, often lead to cracking of the initial support layer, misalignment or even the whole fall off, so that the sealing and supporting functions of the initial support cannot be realized