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Abstract

Содержание

Introduction

Undeniable advantages as shotcrete method of construction works, improvement of equipment, new materials and technology have made it an important and necessary tool for many types of work.

Shotcrete solve the problem of stability of rock in tunnels and other underground facilities. Today shotcrete is a key technology in securing mining:

- in tunneling;

- in the mining industry;

- in hydraulic engineering;

- when attaching construction pits and slopes of coastal structures.

More than 90% of the total use of shotcrete falls on fixing mine workings.

In comparison with conventional concrete, shotcrete is used today in relatively smaller amounts, but solutions to a much wider range of tasks. For example, if:

- Pitpropping device;

- Wall channels;

- Reconstruction and repair of buildings and structures;

- Securing the coastal slopes;

- Creation of refractory linings;

- Fire protection and corrosion protection;

- Creating linings for pools;

- In agriculture (fertilizer pit);

- Plastering and strengthening brick walls.

Shotcrete is a method of building the future thanks to these qualities:

• flexibility of technological operations;

• rapidity of its application;

• economy.

With sufficient power of imagination has no boundaries in the application of shotcrete.

1. Theme urgency

When using shotcrete can be used steel and synthetic fibers. Their main characteristic is that the fibers lead to an increase in the energy characteristics of the material and significantly reduce shrinkage cracks in the shotcrete.

Concrete with a fiber is a new material that is growing rapidly with the advent of new and ever-improving types of fiber, concrete with improved technology and methods of application.

Over the past few years the use of shotcrete reinforced with steel fibers increased significantly. Steel fibers - the Sharok used in shotcrete. Reinforced shotcrete as mine support, recognized engineers, researchers and contractors worldwide.

Conventional short synthetic fibers resistant and durable in a concrete environment. However, their mechanical properties similar to the properties of concrete, they do not alter the properties of concrete in tension.

For this reason, synthetic fibers are not suitable for use when fixing workings. Despite this, in cases where it is necessary only for the reinforcement of shrinkage reduction or repairs suitable synthetic fibers: they are highly effective in the distribution of the microcracks and they reduce rebound during wet spraying method. In addition, synthetic fibers have a positive impact on the fire shotcrete.

2. Goal and tasks of the research

The purpose of the master’s work is to validate the parameters sprayed fiber-concrete bracing for reconstruction of buildings and underground structures.

The main objectives of the study:

  1. Perform laboratory studies of the properties of concrete mixture sprayed with synthetic additives into account, steel polymer and steel fiber;
  2. The parameters of the concrete mix to develop the technology renovation of buildings and underground structures.
  3. To analyze the techniques and technology sprayed concreting;
  4. Develop production schedules reconstruction of buildings and underground structures using fiber-sprayed concrete bracing.

Research object: buildings and underground structures to be reconstructed.

Research subject: the concrete mix used to create fiber-sprayed concrete lining used in the reconstruction of buildings and underground structures.

The idea of research: Using polymer, fiber supplements and steel fibers in the preparation of concrete mix sprayed concreting..

Possible scientific and practical results that are expected in performing the work, novelty and value:

  1. Dependency Determination sprayed improve the strength properties of the pitch-type and percentage fiber supplements;
  2. Development of production schedules erection sprayed fiber-concrete bracing for reconstruction of buildings and underground structures.

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