KR20030061212A - Polymer Impregnated Regeneration Method for Mortar Lining of Water Works Pipe - Google Patents

Abstract

PURPOSE: A construction for regenerating a worn-out pipe of a mortar lining cast-iron pipe for water works is provided to protect the surface of the cast-iron pipe and to increase strength and water-resisting qualities. CONSTITUTION: A construction for regenerating a worn-out pipe(10) of a mortar lining cast-iron pipe is composed of steps of exploring a conduit line for regenerating the worn-out water pipe, and deciding and investigating a working section and position; passing water with a temporary valve after shutting off the water supply of the conduit line and cutting the water pipe corresponding to the working section; removing and discharging fittings attached on a pipe wall by injecting high-pressured water to the cut mortar lining water pipe with a jet cleaner; scratching out aged cement materials which are adhered on the inner wall of the mortar lining water pipe and removing the worn-out surface; removing water inside the pipe and drying the pipe with a hot air generator(28) after completely cleansing the water pipe; coating non-solvent type resin over and impregnating the water pipe after cooling the dried water pipe in a predetermined temperature; drying the inside of the water pipe impregnated with resin in a predetermined temperature and accelerating the hardening thereof; coating and lining the pipe with paints in a predetermined thickness after a hardening process and drying the pipe; and cleansing the pipe with water if the coated film is dried and passing water after connecting the pipe to the conduit line.

Description

Polymer Impregnated Regeneration Method for Mortar Lining of Water Works Pipe}

The present invention relates to a process for regeneration of old pipes of mortar lining cast iron pipes, and more particularly, to impregnated resin in deteriorated mortar-lined cast iron pipes to improve surface protection, increase strength and water resistance. It is about old building rehabilitation method.

In general, the mortar lining pipe of the water centrifugal ductile cast iron pipe of KS D 4316, as defined by the Korean Industrial Standards, is a regulation on the mortar lining applied to the cast iron pipe prescribed in KS D 4311 water centrifugal ductile cast iron pipe.

Moreover, the quality of the lining should not be eroded by tap water, should not adversely affect the water quality of the tap water, it should be uniform in thickness and quality, less absorbent, free from harmful cracks and peeling, and the finishing surface should be smooth.

This regulation is a reinforcement regulation to prevent rust from water pipes. Since its establishment on October 30, 1984, mortar lining pipes have been applied to water pipes buried nationwide.

The rust prevention can be achieved by lining the mortar to the water pipe using the cast iron pipe or steel pipe to some extent, but it was almost impossible to permanently rust with the thin thickness of the mortar lining (minimum 2mm to maximum 10mm).

That is, the mortar lining deteriorates due to water passage after the water pipes are buried, and abrasion due to running water is formed from the surface, and coarse sand is gradually exposed to its function. Eventually it will provide factors that adversely affect water quality.

However, so far, there is almost no method for rehabilitation of the old pipe (mortar lining pipe).

The technical view on the deterioration of general mortar lining is that the lining material in KS D 4316 (mortar lining of centrifugal ductile cast iron pipe for water supply) is cement (portland cement, blast furnace slag cement, fly ash cement) and fine aggregate, It is composed of water and miscible materials, and the lining construction method is dried and cured by centrifugal force (no water content is shown), and then coated with a bitumen-based paint or acrylic polymer or vinyl chloride polymer with a seal coat to complete the product.

The bituminous paint used in the composition of the seal coat is mainly blown asphalt, and as a pigment, carbon black, other alkyd resins, and solvents are used. It is a paint composed of 50 ~ 60% of the solid content, thinner at the time of painting due to dilution of thinner, etc., and 30 ~ 40% of the solid content at the time of coating, and its film thickness is 15 ~ 25㎛ (0.015 ~ 0.025mm), very thin and water resistant. This is weak.

Since it is painted on the surface of mortar lining, only the surface is painted without penetrating into the surface of cement lining.

In addition, the vinyl chloride polymer or acrylic polymer seal coat material is obtained by emulsifying the monomer in water, and the solid content is 40 to 50%. The emulsion particles are agglomerated and applied by evaporation of water. It is a thread coat material.

Since water is diluted during painting (dipping or spraying) with a seal coat, the coating film is about 15 to 25 µm and its water resistance is weak. Emulsion particles emulsified in water do not penetrate into the mortar tissue but are applied and painted on the surface.

On the other hand, the main component of cement is portland cement, in which 3 to 5% of gypsum (CaSO ₄ ) is added to a combination of four components of CaO, Al ₂ O ₃ , SiO ₂ , and Fe ₂ O ₃ , to be pulverized. This cement is hydrated when it comes in contact with water, and it is calcium silicate hydrate called Tobermorite (3CaO · 2SiO ₂ · 3H ₂ O), calcium hydroxide (Ca (OH) ₂ ), calcium aluminate hydrate and calcium sulfoalumina. Many hydrates such as nate hydrates are produced. Hydration is hydrated as it penetrates from the surface of cement particles, and cement dough hardens due to the formation of calcium hydroxide (Ca (OH) ₂ ) as it condenses, losing fluidity and viscosity. Capillary pores are formed therebetween, and are inherently porous due to the water gap due to the excess water used in the construction of mortar, thereby allowing water to be absorbed and permeated.

In addition, although the mortar lining is porous and the water pipe is not rusted even though it is permeable and absorbed, the calcium hydroxide (Ca (OH) ₂ ) produced by the cement hydration of the cement paster has a hydrogen ion concentration (PH). Because it is strong alkaline of 12 ~ 13 degree, it can prevent rust by passivating iron. However, the influence of the external, that is, chlorine ion (Cl ^-) in the carbon dioxide gas or water in the air, the ground, or the pH value (PH) by the calcium hydroxide dissolution and chemical reaction such as by water flowing into the can pressure is reduced to less than 11 When rust is generated, rust causes 2.5 times the volume of iron to expand, which causes the mortar lining to break or crack, and in the case of water pipes, because the lining thickness is very thin, rust is eluted between the pores and prevents rust. There is a problem of losing.

The lining method of mortar lining pipe of the water centrifugal ductile cast iron pipe of KS D 4316 is kneading with cement, fine aggregate, water, and other admixtures, and it is lined inside the pipe by centrifugal force by rotating the water pipe while kneading with cement, fine aggregate, water, and other admixtures. Depending on the size of the aggregates, they are concentrated in the pipe wall, and the fine powder of cement and water float on the upper surface, causing the bleeding phenomenon in which the water floats, and the surface hardens to a very dense surface.

For reference, the following table shows the mortar lining thickness and weight of the water pipe diameter.

Tube nomenclature (diameter) Lining thickness (mm) Weight (about) (kg / m) Standard thickness Average value Minimum value of one point 80 4 3 2 2.2 100 2.8 125 3.5 150 4.2 200 5.6 250 7.0 300 6 5 3 12.6 350 14.7 400 16.8 450 18.9 500 21.0 600 25.2 700 8 7 4 39.0 800 44.7 900 50.2 1000 10 9 5 69.9 1100 76.1 1200 83.7

After mortar lining is cured and dried in the cast iron pipe, the seal coat is applied to seal the cement voids, but it is completely blocked from water by using a hydrophobic coating that is too thin in thickness and opposes the surface properties of the cement's hydrophilicity. This is impossible.

In particular, the water pipe is not stagnant in the water, and the commercial water pressure flows for a long time at a very high flow rate of ⁴ to 10 kg / cm ² , so the seal coat on the surface is lost within a few months, and the surface of the cement mortar lining This is exposed to running water.

Domestic tap water for sterilization by input a large amount of chlorine (Chlorine), depending on the environment of the season and the raw water (intake source), whereby the chloride ion in tap water (Cl ^-) is in the water purification plant has 1.0~2.0ppm summer, winter, 0.8 About 1.5ppm is added and about 0.2ppm remains at the end (faucet) of the tube to sterilize.

Therefore, the amount of chlorine dissipated in the water supply through the water pipe is 0.8 to 1.8 ppm, which reacts with calcium hydroxide in the mortar lining to dissolve calcium hydroxide, penetrates into the lining, and makes pores in the cement larger. Will be reduced. In some buried pipelines, the phenomenon of abrasion of tap water equipment due to the generation of fine aggregates of lining is also detected.

Thus, the method for the regeneration of the aged water mortar lining cast iron pipe according to the present invention is that the hydration action is promoted and the strength increases when the cement mortar action on water is purified, but the calcium hydroxide generated by hydration during water flow It is dissolved in water and eroded.

The white precipitate that is found in the cracks or leaks of the calcium hydroxide in water and the cement mortar is called baektae.

Furthermore, in order to use chlorine for disinfection sterilization of water, it reacts as in the following Chemical Formula 1. Therefore, chlorine is present as hydrochloric acid, and since a large amount of calcium hydroxide, which is a hardened material of cement, is strongly alkaline, it is easily neutralized when contacted with acid to generate salts. Elution of such salts promotes porosity in the mortar, and since hydrochloric acid of inorganic acids dissolves into alumina hydroxide or silicate hydroxide, which are the main components of the cement hardened body, the cement mortar is severely eroded and collapses.

The chemical reaction by such chlorine is as follows.

In this way, the surface strength of the old mortar lining is remarkably lowered by the conventional regeneration method of the mortar lining. Therefore, the coating does not adhere to the lining surface only by applying the paint to the surface on which the mortar lining is formed. Problems such as causing it will not be able to achieve the desired purpose.

The present invention is to solve the above problems, by impregnating the deteriorated mortar lining with a polymer (polymer) or monomer (Monomer) of the synthetic resin to increase the strength of the mortar lining, and to be porous to cause the permeability By impregnating the synthetic resin in the porous material, to complement the loose adhesive surface between the cast iron surface and the lining, harden the base after hardening, to protect the surface of the mortar lining from damage and to reduce the coefficient of friction The purpose of the present invention is to provide a renovation method for the aged pipe of a mortar-lined cast iron pipe for water to prevent rust and to prevent contamination of tap water.

1 is a cross-sectional view showing a cross section of an aged mortar lining cast iron pipe,

2 is a cross-sectional view showing a state cut for regeneration of cast iron pipe,

3 is a cross-sectional view showing a state of removing foreign matter by spraying high pressure water on the inner wall of the cast iron pipe,

Figure 4 is a cross-sectional view showing a state in which scraped off and stuck to the stuck goods,

5 is a cross-sectional view showing a state to dehydrate the washed tube;

6 is a cross-sectional view showing a state of drying with a hot air generator,

7 is a cross-sectional view showing a state of impregnating resin;

8 is a cross-sectional view showing a state in which the lining by applying a paint on the inner wall of the resin impregnated tube,

9 is a cross-sectional view showing a state of connecting a water pipe made of rehabilitation;

10 and 11 is a cross-sectional view showing a jet engine combustion device of the can-enable combustion method with a hot air generator.

♣ Explanation of symbols for main part of drawing ♣

10: water pipe 11: mortar lining

16: Jet Cleaner 20: Hydraulic Turbine

26: dehydration morph (MOP) 28: hot air generator

30: resin sprayer 34: paint sprayer

The present invention provides a first step of exploring the pipeline for the rehabilitation of the old water pipe to set the working interval and the work position to investigate the object; A second step of passing water through a wig after cutting the water pipe and cutting the water pipe corresponding to the work section; A third step of spraying high-pressure water with a jet cleaner on the cut old mortar-lined water pipe to remove and remove deposits on the pipe wall; A fourth step of scraping off the cement sinter stuck to the inner wall of the aged mortar lining water pipe and removing the aged surface; A fifth step of removing water in the pipe and drying with a hot air generator when washing of the water pipe is completed through the third and fourth processes; A sixth process of cooling the dried water pipe to a predetermined temperature and then applying and impregnating a non-solvent type resin; A seventh step of drying the interior of the water pipe in which the resin is impregnated to a predetermined temperature to promote curing; An eighth step of coating, lining, and drying the coating to a predetermined thickness in the state where the curing is performed; When the coated coating film is dried, it is characterized in that it is made of a ninth process of carrying out the water after the connection to the corresponding connection portion of the water pipe after washing with water.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1 to 9 is a view showing a process for the regeneration method of the old mortar lining pipe according to the present invention.

First, in the first step, the survey operation of the aged water pipe 10 for rehabilitation is performed, and the work position is set by exploring the pipeline before the start of the work. The construction length of one section is about 60 ~ 80m, and it is determined according to the site situation, and the pit of the work area is excavated, its size is about 1.5 × 1.8m, its depth is about 1.5m, and it is enough to cut the water pipe 10. After the space is secured, reinforcement boards, etc. are attached around the work gang to prevent soil from falling down.

The second step is cutting and preparing work. After closing the opening / closing valve corresponding to the work section, cut the water pipe 10 pipe about 1m to insert the lake or mechanism of the work machine, and then cut off both ends of the work section. The pipe 14 is blocked by the wig 12 and passed through, and only 60-80m of the water pipe 10 corresponding to the work section is cut off. Wigs 12 at both ends use a lake attachment valve to be used for jet cleaning.

The third process is a jet cleaning operation, in which a rear-projection cleaning nozzle 18 is mounted at the tip of the hose 17 of the jet cleaner 16 and inserted into the cut water pipe 10. By spraying high pressure water (250 ~ 300kg / cm ² ) to remove deposits, such as scale attached to the wall of the water pipe 10, and remove the fine aggregate of the mortar lining (11) surface is deteriorated at the same time Anti-elastic forces the scales out of the tube.

The fourth step is a scraper and jet cleaning operation, and soil cement cement adhered to the surface of the aged mortar lining 11 serves as a barrier to penetration of the polymer impregnation operation. Towing the scraper to the winch and at the same time jet cleaning or to install the hydraulic turbine 20 and the brush head 24 in the cleaning high pressure hose 22 of the whole process to promote the work at low speed . This operation removes the aging surface from the surface of the mortar lining 11 to create a base that facilitates the penetration of polymers or monomers.

The fifth step is dehydration and drying, and when the washing operation in the water pipe 10 is finished, the water is removed from the water pipe 10 by using a dehydration morph (MOP) 26 or a dewatering sponge, and then blows hot air (200 ° C. or lower). The mortar lining 11 is dried so that the moisture content in the tissue is 3 to 5% or less. At this time, if the hot air temperature (inlet temperature) is 200 ℃ or more adversely affects the aged mortar lining 11, care should be taken, if necessary, can be allowed up to 300 ℃ temporarily.

The hot air generator 28 used here attaches a can-ennucleated combustion device using the principle of a jet engine to one end of the water pipe 10 and sends compressed air from the outside to a high-speed blower (blower). Use the method. The cannula-type combustion apparatus uses a jet engine combustion method, as shown in FIGS. 10 and 11, and FIG. 10 is a small-diameter combustion engine (one), and FIG. 11 is a large-diameter combustion engine ( 4) is installed. Suitable combustion apparatus may be used to control the temperature of the hot air or the amount of hot air.

The sixth step is to impregnate the resin, and after the hot air drying is finished in the process and the water content on the inner wall of the water pipe 10 drops, the surface temperature is cooled to about 60 to 80 ° C., and then the resin is non-solvent type. (31) is applied to the resin injector 30 through the resin pumping hose (32). The impregnation amount is preferably sprayed in an amount of more than about 20% above the theoretical amount by calculating an analytical value obtained by taking a sample in advance and testing the absorption rate. After the coating is finished, the hot air generator 28 is heated to warm air of about 60 to 80 ° C. to cure it in a short time.

The impregnating resin may use a reaction initiator or a two-component reactive synthetic resin or a polymer alone in the monomer of the synthetic resin, but a low viscosity (500 cps, 25 ° C.) or less so as to easily penetrate the capillary inside the aging lining. use. In order to reduce the viscosity, it is preferable to use a low viscosity polymer because the diluent may be contaminated with tap water by the residual organic solvent after dry curing.

The seventh step is a hardening promoting operation, in order to harden the impregnated resins, the hot air generator 28 of the working step of the fifth step is operated to maintain the internal temperature at 60 to 80 ° C to promote hardening.

In the eighth process, it is preferable to use over-coat lining, and the coating material for the top lining uses a component of the same series as the resin impregnation component. This is because the adhesion between the mortar lining surface and the top lining 36 should be increased, so that the rust preventive force can be permanently compensated.

Top coat lining work is equipped with a paint injector 34 to the paint pumping hose 35 of the sprayer to pass through the pipe at a constant speed, and the thickness of the coating film is applied to 1.0 ± 0.3mm to complete the painting once. .

In addition, after the coating, the hot air generator 28 is used to promote hardening by hot air heating and shorten the time until water passage.

Next, in the ninth process, after confirming that the coating film is cured and dried by the customs and water supply work, the cut portion of the water pipe 10 is connected to the designated connector to carry out water supply after washing with water.

The analysis of physical properties of reclaimed mortar lining cast iron pipes and mortar lining water pipes, which are estimated to be about 5 years old, has been carried out using abrasion resistance test of the lining surface and the test of specific gravity and absorption rate of mortar lining. Comparing the results obtained through the following table.

Item Old tube lining Fuse lining Mortar Lining Abrasion Resistance Test KS F 2429 Abrasion Loss 20.5 g 14 g Water Absorption KS 2518 9.4% 5.73% Visual inspection (surface) Surface mortar collapsed Seal coat is perfect (surface black)

As a result of the test results of the mortar lining structure, the increase in the absorption rate and the decrease in specific gravity are due to the enlargement of the porous pores in the tissue and the mortar lining collapse due to the decrease of the mortar surface hardness as in the wear resistance test. It is present.

As a result of examination of various specimens, the mortar lining pipe of centrifugal ductile cast iron pipe for water supply begins to aging about 5 years after being buried and passed through, and surface collapse starts around 7 years.

On the other hand, when the cement is cured, about 25% of water is left as crystal water and about 15% is gel. Capillary pores are formed due to evaporation of the remaining 60% of water and finally 15% of gel water. Cement mortar is strongly alkaline and sensitive to erosion of acidic solutions. In the air, carbon dioxide or other gases (Gas), which are diffused into the cement mortar through capillary pores, dissolve in the pore water and may act as an acid solution.

Cement mortar pores promote the absorption of water to transport substances of harmful constituents.

Although the physical wedge effect of the surface coating can be expected using this porosity, some background treatment is required to ensure the adhesion of the cement mortar and the paint. This includes the removal of a substance to which a coating material or impregnation material is not attached, or a surface which is peeled off after construction, which becomes a defect of a coating film.

Another purpose of the background treatment of aged cement mortar is to remove defects and to ensure a continuous coating. If very old cement mortar linings need to be rebuilt, the basis for the surface treatment (surface treatment) is only one and the surface is polished until a normal ground is produced.

Unlike sewer pipes, there is no severe deterioration, but scrapers, wire brushes, and jet cleaning are used on the surface of the surface damaged by the rapid flow of tap water or on the surface where the strength is lost due to chlorine in the water. Should be removed by means of high pressure water cleaning. The removal of the poor mortar lining on the surface facilitates the impregnation of the resin, and by sufficiently impregnating the voids in the mortar, the physical wedge effect of the top coat is expected, thereby achieving the purpose of semi-permanent rust prevention.

Impregnant is enhanced to a higher than by easily penetrated by curing the capillary pores of the cement mortar lining initial compression strength (350~400kg / cm ²⁾ strength (epoxy impregnated 800~1200kg / cm ²⁾ in the cement lining internal tissue , The modulus of elasticity is increased by 30 to 80%, and the absorption rate is reduced to 0.72% to enhance performance.

The impregnating polymer may be a two-component reactive polymer, but the cured product should have excellent water resistance, have no adverse effect on water quality, and have a resin compatible with a top coat material. Should be chosen.

Generally available polymers include furan resins, polyester resins, unsaturated polyester resins, epoxy resins, polyurethane resins, phenol resins, acrylic resins, etc., but the most ideal polymer resin is an epoxy resin. Epoxy resin is the most widely used polymer for maintenance of facilities for water and sewage because it has excellent workability, strong water resistance and chemical resistance, and is safe for water.

By impregnating polymer and coating the top coat with cement mortar lining, the compressive strength is increased, and the elastic modulus is increased so that the lining has the structure of perfect water tightness and airtightness, so it is resistant to the absorption and permeability of water or other materials and freeze-thawing resistance. It is very excellent. In addition, the impregnated polymer does not contain components having poor chemical resistance, such as cement hydrate, and because the watertight structure is formed, does not contain components with poor chemical resistance, and has excellent chemical resistance because the watertight structure is formed, Excellent wear resistance, impact resistance and electrical insulation.

The top coat (resin) is coated with a thickness of 1.0 ± 0.3mm to finish the exterior due to the damaged rough part of the cement mortar, thereby lowering the coefficient of friction with the tap water to improve the flow rate so that there is no obstacle to water flow.

As described above, the old pipe regeneration method of the mortar lining cast iron pipe of the present invention removes foreign substances adhering to the water pipe wall for regeneration of the old mortar lining cast iron pipe, and then impregnates the mortar lining with resin to perform top coat coating to generate green water and scale. It is prevented, it is not necessary to replace the old pipe buried by the construction method of the present invention to the new building to prevent excessive spending of the budget, prevent traffic obstacles caused by the increase of traffic in the city according to the construction, and other underground buried material (gas pipe, high pressure) It is possible to prevent problems such as damage to electric wires, communication cables, etc., and by coating the inside of the water pipe with a resin to prevent permanent rust in the pipe, leakage of water and contamination of tap water, thereby providing cleaner water to consumers.

Claims (7)

A first step of exploring a pipeline for rehabilitation of an aged water pipe to set and inspect a work section and a work position; A second step of passing water through a wig after cutting the water pipe and cutting the water pipe corresponding to the work section; A third step of spraying high-pressure water with a jet cleaner on the cut old mortar-lined water pipe to remove and remove deposits on the pipe wall; A fourth step of scraping off the cement sinter stuck to the inner wall of the aged mortar lining water pipe and removing the aged surface; A fifth step of removing water in the pipe and drying with a hot air generator when washing of the water pipe is completed through the third and fourth processes; A sixth process of cooling the dried water pipe to a predetermined temperature and then applying and impregnating a non-solvent type resin; A seventh step of drying the interior of the water pipe in which the resin is impregnated to a predetermined temperature to promote curing; An eighth step of coating, lining, and drying the coating to a predetermined thickness in the state where the curing is performed; When the coating film is dried, the old pipe rehabilitation method of the mortar lining cast iron pipe for water, characterized in that made of a ninth step of performing the water after the connection to the corresponding connection to the water pipe after washing with water. The method of claim 1, wherein in the fifth step, the hot air generator for drying is applied to a can-null combustion jet engine combustion device, the temperature of the hot air is 200 ~ 300 ℃ or less, the moisture content in the mortar lining tissue An old pipe rehabilitation method for a mortar-lined cast iron pipe for water, characterized in that it is 3 to 5%. The method of claim 1, wherein in the sixth step, the surface temperature before the impregnation of the resin is 60 ~ 80 ℃, the impregnation amount of the resin is sprayed at 20% or more than the theoretical value, the curing temperature for curing the applied resin is A retirement pipe renovation method for a mortar-lined cast iron pipe for water, characterized in that it is 60 to 80 ° C. The method of claim 1, wherein the impregnating and lining resin using a reaction initiator in the monomer or any one of a two-component reactive synthetic resin or polymer alone, the resin has a viscosity of 500cps, 25 ℃ or less mortar for water Old pipe rehabilitation method of lining cast iron pipe. The old pipe regeneration method according to claim 4, wherein the polymer is any one of a furan resin, a polyester resin, an unsaturated polyester resin, an epoxy resin, a polyurethane resin, a phenol resin, and an acrylic resin. The method according to claim 1, wherein in the eighth step, the coating material is 1.0 ± 0.3 mm thick and the number of coatings is finished once. The old pipe rehabilitation method according to claim 1, wherein the rehabilitation method is applied to water and sewage cast iron pipes.