METHOD OF PRODUCTION OF A GROUT AND A GROUTING METHOD

Abstract

A method for production of a grout comprises the steps of: a) acquiring a batch cement for a ball mill, b) forming in the ball mill a cement powder also called a nano-cement powder, c) pouring the nano-cement powder obtained in step b) to a rotary mixer, d) adding water to the rotary mixer, e) mixing the water and the nano-cement powder until a homogenous mixture of the nano-grout or the nano-slurry is obtained, f) pouring the nano-grout or the nano-slurry obtained in step e) from the rotary mixer to a distributing device.

A grouting method comprises the steps of: a) preparing the construction site for the grouting application, b) applying a grouting material to the construction site or specific places of the construction site, c) curing the applied grouting material for a predetermined amount of time, wherein the grouting material is the nano-grout or the nano-slurry.

Claims

1. A method for production of a grout, comprising the steps of: a) acquiring a batch cement for a ball mill, b) forming in the ball mill a cement powder, wherein forming of the cement powder is performed by grinding the batch cement in the ball mill, wherein the ball mill includes a plurality of mill balls, wherein the average particle size of the produced cement powder is between 2 nm and 100 nm, and as such is also called a nano-cement powder, c) pouring the cement powder or the nano-cement powder obtained in step b) to a rotary mixer, d) adding water to the rotary mixer containing the cement powder or the nano-cement powder produced in step b), wherein a weight ratio of the water and the cement powder or the nano-cement powder is from 1:100 to 10:100. e) mixing the water and the cement powder or the nano-cement powder for a period of time T from 10 minutes to 120 minutes until a homogenous mixture of the nano-grout or the nano-slurry is obtained, wherein a rotational speed of the rotary mixer is between 70 rpm and 120 rpm, f) pouring the grout or the nano-grout or the nano-slurry obtained in step e) from the rotary mixer to a distributing device.

2. The method according to claim 1, wherein the weight ratio of the batch cement to the plurality of the mill balls is between 1:05 and 1:30 wt/wt.

3. The method according to claim 1, wherein the ball mill is configured to rotate at a rotational speed between 600 rpm and 4200 rpm.

4. The method according to claim 1, wherein the batch cement is selected from any commercial cement available on the market.

5. A grouting method, comprising the steps of: a) preparing the construction site for the grouting application, b) applying a grouting material to the construction site or specific places of the construction site, c) curing the applied grouting material for a predetermined amount of time, wherein the grouting material is the nano-grout or the nano-slurry obtained according to claim 1.

6. The grouting method according to claim 5, wherein the reactivity of the nano-grout is between 0.99 and 11 min.

7. The grouting method according to claim 5, wherein the dispersibility of the nano-grout is between 0.009 and 0.12 Pa-s.

8. The grouting method according to claim 5, wherein the nano-grout includes carbon nano-tubes and/or graphene and/or carbon black and/or nano silica sol and/or nano calcium carbonate and/or nano clay and/or nano carbon.

9. The grouting method according to claim 5, wherein the particles of the nano-grout have an average surface area of 150-380 m.sup.2/g,

10. The grouting method according to claim 5, wherein the dispersibility of the particles of the nano-grout is between 0.009 and 0.12 Pa-s.

11. The grouting method according to claim 5, wherein the particles of the nano-grout have high compatibility with the grout matrix.

12. The grouting method according to claim 5, wherein the nano-grout or nano-slurry includes an accelerator selected from a group consisting of: calcium chloride, sodium silicate, sodium hydroxide.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0056] These aims together with other objects and advantages which will become subsequently apparent reside in the details of the construction and operation as more fully hereinafter described and claimed, reference being made to the accompanying drawings forming a part hereof, wherein the same numerals refer to the same parts throughout.

[0057] In drawings

[0058] FIG. 1 illustrates schematically the work principle of the ball mill for the nano-grout production,

[0059] FIG. 2 illustrates schematically the work principle of another embodiment of the ball mill,

[0060] FIG. 3 illustrates a XRD diagram before the nano-grout production process, consistent with one or more exemplary embodiments of the present disclosure,

[0061] FIG. 4 illustrates a XRD diagram after the nano-grout production process, consistent with one or more exemplary embodiments of the present disclosure,

[0062] FIG. 5 illustrates a Zeta analysis for the nano-cement,

[0063] FIG. 6 illustrates an Scanning Electron Microscope (SEM) image of the nano-grout particles,

[0064] FIG. 7 illustrates a DLS results with Pade Laplace Dispersion Technique for Nano Slurry.

DETAILED DESCRIPTION OF INVENTION AND PREFERRED EMBODIMENT

[0065] Referring to the drawing, FIG. 1 shows schematically a principle of operation of a ball mill (not claimed). The ball mills are well known, therefore the construction will be not described here in details. However, operating parameters of the ball mill, for example the size and material of the balls, the weight ratio of the balls to the batch cement, rotational speed of the ball mill cylinder, inclination of the rotational axis, time of operating, etc., are changeable and are to be set according to the requirements of the output material (the nano-cement). It can be seen on FIG. 1 that during operation, the ball mill cylinder rotates according to the direction of the arrow A. The crushing medium G, which includes a plurality of metal balls of sizes 1 cm, 1.5 cm and 2 cm, rotate inside the cylinder around an axis. The bottom plate of the device and the cylinders containing the material to be grinded and/or crushed and/or shredded which is the batch cement, M, rotate around an axis perpendicular to each other in opposite directions (one clockwise and the other counterclockwise). These movements are creating a centrifugal force. The balls first are pressed to a wall of the cylinder due to the centrifugal force caused by the rotational motion of the chamber and then the centrifugal force caused by the rotational motion of the plate dominates the force and, the balls in the cylinder are falling on the batch cement material particles in a specific position due to the gravity and are causing them to crush and ultimately convert the particles to nano size. The wording nano size or nano-grout in this description means a size from around 2 nm to around 100 nm (nanometers). In simpler terms, these methods are among the methods in which by crushing and shredding larger materials and particles into smaller particles and continuing this process to the size of nanometers, they become nanoparticles, which means a particles with the average nano size, in general in diameter of the majority of the particles, as described above. The particle size of the batch cement may determine the degree of purity, the shape of the material particles and the degree of quality of the grout or nano-grout. Another construction of the ball mill (not claimed) is shown on FIG. 2. This planetary ball mill includes a number of ball mill cylinders (grinding jars) which are rotatably placed on an independently rotatable base plate. The directions of rotation B of the grinding jars and the directions of rotation A of the base plate are opposite. The grinding balls in the grinding jars are subjected to superimposed rotational movements, the so-called Coriolis forces. The difference in speeds between the balls and grinding jars produces an interaction between the frictional and the impact forces, which releases high dynamic energies. The interplay between these forces produces the high and very effective degree of size reduction of the planetary ball mill. In the next step the grout powder or the nano-grout powder obtained in the previous step is poured to a rotary mixer, where in the next step water is added, wherein the weight ratio of the water and the grout powder or the nano-grout powder is 1:100 and 10:100 (nano-cement powder:water). The water and the grout powder or the nano-grout powder is mixed for a period of time T 10 minutes with rotational speed of the rotary mixer 200 rpm. After this time a homogenous mixture of the grout, also called nano-grout or nano-slurry, is obtained. Next the grout or the nano-grout or the nano-slurry is poured from the rotary mixer to a distributing device (not claimed). Depending on the application, the distributing device can be a pump, a syringe, a nozzle, or a spray gun. The weight ratio of the batch cement to the plurality of the mill balls is 1:2 wt/wt. The rotational speed of the ball mill is set for 400 rpm.

[0066] Some specific examples (embodiments) of nano-grouting are: [0067] Water-blocking nano-composite cement-based grouting materials: This is a type of nano-grouting that uses a mixture of ordinary Portland cement, sulfoaluminate cement, water-reducing agent, early strength agent, nano silica sol, and cellulose to create a grout that has good fluidity, pumpability, setting time, compressive strength, and anti-scour performance. This grout can be used for water blocking and reinforcement in underground engineering construction such as hydropower projects, mines, tunnels, etc. [0068] Silica sol as grouting material: This is a type of nano-grouting that uses colloidal solutions of nano-sized silica particles to create a grout that has low viscosity, high penetration, and high strength. This grout can be used for permeation grouting of rock to prevent the leakage of water into tunnels and hard rocks. The gelling time and strength development of this grout can be controlled by adding different salt solutions such as NaCl and KCl. [0069] Nano-composite cement: This is a type of nano-grouting that uses a mixture of cement, fly ash, water-reducing agent, early strength agent, and nano-materials such as nano silica sol, nano calcium carbonate, nano clay, and nano carbon to create a grout that has improved fluidity, setting time, hydration, strength development, and durability. This grout can be used for stabilization of loose sands and improvement of soil properties.

[0070] FIG. 3 and FIG. 4 shows the results of the XRD experiments. The nano-grout particles, respectively, are after the production process. The results of the XRD test are presented before and after the procedure. The X-ray diffraction (XRD) is a versatile non-destructive analytical technique used to analyze physical properties such as phase composition, crystal structure and orientation of the powder, the solid and the liquid samples. These figures show the crystallographic structure of the solid particles of the grout.

[0071] The results of the XRD test after the process are as follows: According to the presented results, the peak points in the whole nano production process have been constant, which shows that no additional material in the nano production process has been added to the nano-grout. Also, the results of XRD test on the sample before and after the nano-production process show that no changes have occurred in the powder components. FIG. 5 illustrates a zeta analysis for the nano-grout. The magnitude of the zeta potential gives an indication of the potential stability of the colloidal system. If all the particles in suspension have a large negative or positive zeta potential then they will tend to repel each other and there will be no tendency for the particles to come together. The result of the analysis indicated on FIG. 5 is that in the range from 30 to 60 mV and from 30 to 60 mV the zeta potential is stable, but in the range from 30 to 30 mV the zeta potential is unstable. FIG. 6 illustrates a Scanning Electron Microscope (SEM) images of the solid grout particles after the process of nano-production. As shown, the measured sizes of three chosen particles are 61.87 nm, 64.05 nm and 62.09 nm, respectively. FIG. 7 illustrates a Dynamic light scattering (DLS) size distributions of nano slurry samples obtained by using the Pade Laplace dispersion technique. The Pade Laplace method is a high-resolution inversion algorithm that can resolve multimodal distributions and account for polydispersity. The nano slurry samples consist of nanoparticles suspended in a liquid medium. The DLS technique measures the intensity fluctuations of scattered light due to the Brownian motion of the nanoparticles and infers their size distribution.

[0072] Nanogrouting provides some advantages over conventional grouting methods, such as: [0073] Reducing the environmental impact: Nanogrouting can use less water and cement than conventional grouting methods. Nanogrouting can also use eco-friendly nanomaterials that are biodegradable and nontoxic. [0074] Enhancing the efficiency and effectiveness: Nanogrouting can reduce the cost and time of grouting operations by using less material and achieving faster setting and curing. Nanogrouting can also improve the quality and reliability of grouting results by creating stronger and more durable bonds with the surrounding structures. [0075] Expanding the application range: Nanogrouting can overcome some limitations of conventional grouting methods, such as low injectability, high viscosity, poor adhesion, or low resistance to dynamic loads. Nanogrouting can also adapt to different geological conditions, such as dry, wet, or moist environments.

[0076] In describing a preferred embodiment of the invention, specific terminology is resorted to for the sake of clarity. However, the invention is not intended to be limited to the specific terms so selected, and it is to be understood that each specific term includes all technical equivalents which operate in a similar manner to accomplish a similar purpose.