JPH03193648A - Cement-based filler composition and method for lining existing pipe - Google Patents

Abstract

PURPOSE:To improve the adhesive strength of the composition by mixing specified amts. of a frother contg. a higher alcohol sulfonate, triethanolamine and PVA, a setting moderator contg. an inorg. oxide and water into cement. CONSTITUTION:A liq. mixture of a frother contg. higher alcohol sulfonate, triethanolamine and PVA and dilution water and compressed air from a compressor 2 are mixed in a specified ratio using a foaming cylinder. The prepared foam, 100 pts.wt. of cement such as portland cement, 7.0-8.0 pts.wt. of a setting conditioner contg. an accelerator such as Al2(SO4)3 and a retarder such as a polycarboxylic acid-based compd., as required, and 40-50 pts.wt. of mixing water are uniformly mixed by a mixer 1 to obtain a foam mortar as the cement-based filler composition. The inside of an existing pipe is cleaned, a new pipe for reconstructing is inserted, and the foam mortar is injected into the gap of about 20-500mm between the existing pipe and the new pipe, aged and hardened.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a cement-based filler composition used for repairing existing pipes such as aging sewer pipes and a lining method for repairing the same.

(Prior Art) A relining method is known as a method for repairing aging buried existing pipes. In this construction method, a strip-shaped original piece is spirally wound using a pipe-making machine installed in a manhole and inserted into the existing pipe as a new rehabilitation pipe, and then foam mortar is injected into the gap between the existing pipe and the new rehabilitation pipe. Then, by hardening the foam mortar as a filler (also called backfilling material), three parts consisting of the existing pipe, backfilling material, and renovated new pipe are cured.
This is a method of forming layered composite pipes and restoring old pipes to the same strength as new pipes.

Japanese Patent Publication No. 64-2834 proposes a cement-based injection material composition for use in the above method and a method for lining existing pipes using the same. This cementitious injection material composition consists of cement, a water-soluble cellulose ester, a cement dispersant, an antifoaming agent, and water, and bentonite is added as necessary. The above construction method involves injecting such a composition into the gap between the existing pipe and the renovated new pipe and curing it.

(Problems to be Solved by the Invention) However, since the cement-based injection material composition proposed in the above patent publication has a specific gravity greater than 1.0, it is difficult to prevent the renovated pipe from floating during injection. .

In order to reduce the specific gravity of the injection material composition, a method has also been proposed in which a foaming agent such as a surfactant is added to form a cellular mortar. However, in the resulting cellular mortar,
Since the strength of the foam is low, the foam disappears after filling and the volume decreases. As a result, gaps are formed in the filling, reducing the strength of the resulting composite tube.

A method of lowering the specific gravity by adding pearlite or styrene beads instead of a foaming agent has been proposed, but in this case, the resulting mortar has poor fluidity and the gap between the outer and inner tubes is insufficient. It has the disadvantage of not being satisfying.

The composition of the above-mentioned publication also has the disadvantage that it requires a long curing time and many days for curing, thus requiring many days for construction. Since the fluidity is not very good, the injection pressure has to be increased.

In addition, since it generates significant heat during curing, it can only be applied to refurbished new pipes that have high external pressure strength and good heat resistance, and there is a problem in that the types of refurbished new pipes are limited.

In general, cementitious filler compositions used for the above purposes have good fluidity to the extent that continuous injection is possible, the gel time can be adjusted, measures to prevent new pipes from floating are easy, and after curing, Various performances are required, such as no shrinkage and no breathing phenomenon.

(Means for Solving the Problems) The cementitious filler composition of the present invention is a composition containing cement, a foaming agent, a setting modifier, and water, wherein the foaming agent is a higher alcohol sulfonic acid trichloride. Contains an ethanolamine salt and polyvinyl alcohol, the setting modifier contains an inorganic oxide, and based on 100 parts by weight of cement, the foaming agent is 0.50 to 0.65 parts by weight, and the setting modifier is 7 parts by weight. .0 to 8.0 parts by weight and water in a proportion of 40 to 50 parts by weight, thereby achieving the above object.

The method for lining an existing pipe of the present invention includes the step of filling and hardening the cement-based filler composition into the gap between the existing pipe and the new rehabilitated pipe inserted into the existing pipe, thereby achieving the above object. achieved.

The inventors have found that by adding a setting regulator to cement milk and mixing it with a foaming agent that has been foamed in advance, a cement-based filler composition that satisfies the various performances described in the prior art section above can be obtained. We have confirmed that this composition can be used to easily repair existing pipes, and have completed the present invention.

As the cement used in the composition of the present invention, any commonly used cement can be used. Examples include ordinary Portland cement, blast furnace cement, silica cement, and fly ash cement. In particular, general-purpose ordinary Portland cement can be suitably used.

The setting regulator contains an accelerating agent and, if necessary, a setting retarder. The quick setting agent is an inorganic oxide (mineral substance) such as aluminum sulfate, calcium oxide, and sulfur trioxide, and the setting retarder is a polycarboxylic acid compound. It is desirable to mix the setting retarder at a ratio of 1 to 4 parts by weight. Such a setting modifier is added in an amount of 7.0 to 8.0 parts by weight per 100 parts by weight of cement. If the amount of setting modifier added is too large, the viscosity will become too high and the injection pressure will become high. If the amount of setting modifier added is too small, the curing time of the resulting foam mortar will be prolonged.

As the foaming agent, a mixture of higher alcohol sulfonic acid, triethanolamine salt, polyvinyl alcohol and water is used. The foaming agent is added in an amount of 0.50 to 0.65 parts by weight per 100 parts by weight of cement. If the amount of foaming agent added is too large, the required strength will not be obtained, and if it is too small, the specific gravity of the resulting foam mortar will increase.

The amount of water is 40 to 50 parts by weight per 100 parts by weight of cement. If the amount of water added is too large, the viscosity will be insufficient, and if it is too small, the fluidity will be insufficient.

The cementitious filler composition of the present invention having the above composition is preferably made into foam mortar by the process shown in FIG. First, foam is produced in advance by mixing a mixture of a foaming agent and dilution water with compressed air from the air conditioner bracer 2 at a volume ratio of 1:20 to 1:30 using a foaming cylinder. The thus prepared foam, weighed cement, setting modifier, and kneading water are mixed into a spiral mixer 1.
Mix evenly. The foam mortar produced by this method has a high foam strength, and material separation due to the formation of floating ice does not occur. In FIG. 1, P is a pump, R is a regulator, and I is a heater.

The foam mortar of the cementitious filler composition of the present invention can of course be produced by a conventional method by stirring cement, a setting regulator such as an accelerating agent, a foaming agent, and water in one mixing tank. It is possible. However, the foam mortar produced by this method does not have very strong foam strength, and if left undisturbed after preparation, the foam may break and cement components may settle, generating floating water and causing material separation.

The method for lining existing pipes according to the present invention using the foam mortar obtained by the above method is typically carried out by the following steps.

■Clean the inside of the existing pipes by high-pressure washing.

■A synthetic resin strip profile is wound into a spiral cylinder using a pipe-making machine installed at the bottom of the manhole.
The manufactured spiral pipe is inserted into the existing pipe as a new refurbished pipe.

■Prior to injection, seal the pipe opening of the attached pipe that branches from the existing pipe, seal the gap between the end of the existing pipe and the end of the refurbished new pipe, and use the backfilling material ( Install the inlet for foam mortar).

■Collect the sewage flowing into the new pipe, or use a water truck to fill the new pipe with water (to prevent floating).

■Snake pump (Wangen pump) uses foam mortar continuously produced in an on-board plant to fill the gap between the existing pipe and the new renovated pipe.
or squeeze pump.

■After curing, drill a hole in the seal part of the existing installation pipe opening and insert the new refurbished pipe and the installation pipe.

■Clean the area within the renovated area.

In the above process, the gap for foam mortar injection is 20
~50mm is sufficient, and the injection length is 20~100mm.
m, or even more.

As described above, the following effects can be obtained by using the foam mortar of the cementitious filler composition of the present invention.

(1) Since foam mortar has good fluidity, pouring work can be easily performed at low pressure and in a short time. Since there is no material separation, there is no problem of the material clogging the gap during the injection process, and it becomes possible to easily inject even narrow gaps.

(2) Since the specific gravity of foam mortar is less than 1.0 (usually about 0.8), if the new pipe is filled with water during injection, the new pipe will not float, and the new pipe will float. Preventive measures can be as simple as filling water with water.

(3) Since foam mortar is given viscosity and thixotropy, it improves adhesion between existing pipes and renovated new pipes after injection. As a result, a high-strength three-layer composite pipe with improved adhesive strength after curing and a strongly integrated structure can be obtained.

(4) The gel time of foam mortar can be arbitrarily adjusted by changing the amount of setting modifier added to the cement. The gel time may be 30 to 60 minutes. Therefore, the renovated pipe can be fixed in a short time, and the number of construction days can be shortened.

On the other hand, when conventional foam mortar is used, floating ice is formed over time after injection, causing material separation, and it is necessary to repeatedly pour foam mortar while discharging the floating ice many times, which increases the number of construction days. will be significantly extended.

(Example) Next, examples will be given.

(Margin below) ~D) Foam mortar was prepared from each.

(1) Test sample composition ratio table 1 (2) Experimental method In a conical container (P funnel) with a capacity of 1725 cnf (1)
The foam mortar obtained in Section 3 was poured into the container, and it was determined how many seconds it would take for the mortar to flow down.

(3) Experimental Results Table 2 Figure 2 shows the results of investigating the relationship between foam mortar specific gravity and fluidity.

2. Backfillability Test Foam mortars E and F having the compositions shown in Tables 3 and 4 were prepared and the following tests were conducted.

(1) Test method A synthetic resin spiral tube (renovated new pipe) with an outer diameter of 266φ and an inner diameter of 250φ was inserted into a Huum tube with an inner diameter of 300φ installed at a gradient of 5% to create an experimental pipe line with an extension of 20 mm. , the foam mortar of the present invention (specific gravity 0.8) was injected. Prior to injection, the spiral tube was filled with water to prevent the tube from floating. One hour after filling, the water in the tube was drained, and the degree of floating of the spiral tube was measured. Furthermore, after 10 days, the tube was cut into slices and the degree of filling with foam mortar was observed. The results are shown in Table 5.

(Left below) 3. Dimensional shrinkage test (1) Test method according to JfS A 1129, IOX 10x 40c
A foam mortar was filled into a formwork of 250 cm, and a gauge plug was embedded and fixed in the gap with a gage length of 250 cm. Three pieces of foam mortar having the composition A shown in Table 1 were molded, and the molds were cured in a moist air box until a specified age.The amount of drying shrinkage was measured using a Whitmore gauge, and the weight change rate was also measured. . The base length was measured the day after molding. The results are shown in Table 6.

(Margins below) 4. Gel time adjustment test We investigated whether the gel time could be adjusted by adding the quick-setting agent to the cement. The gel time was defined as the time required to pour the test solution into a paper cup and turn it upside down until the test solution did not fall out.

As a test solution, a foam mortar having the composition A shown in Table 1 and obtained by adding an quick-setting agent in the proportion shown in Table 7 to the components excluding the quick-setting agent was used. In Table 7, C indicates the solid content of the cement composition.

Table 7 Temperature: 20℃ Specific gravity: 0.82 The relationship between temperature and gel time for each foam mortar is shown in the third table.
As shown in the figure.

5. Composite Pipe Destruction Test This test was conducted to determine the compressive strength of a composite pipe that was renewed using the method of the present invention to replace an existing pipe that had deteriorated due to cracks and erosion.

Tests were conducted using new pipes with lining, cracked pipes with lining, and ceramic pipes. As shown in FIG. 4, inside these tubes 10,
A belt-shaped original piece of plastic was wound spirally using a pipe-making machine and inserted into the tube as fresh snow. Foam mortar was filled between these tubes. The composition of the foam mortar is shown in Table 8. A compressive strength test was conducted on the resulting composite tube. In addition, all the samples used were pipes of fixed length, and the method was carried out based on JIS^5303 to measure the load and the inner surface condition of the refurbished new pipe.

The results are shown in Table 9.

(Leaving space below) Discussion By backfilling cracked old pipes with the foam mortar of the present invention, a three-layer composite pipe that is integrated with a renovated new pipe can be obtained, and the composite pipe has a breaking strength exceeding the JIS standard. It has strength. Its strength was greater than that of a new pipe without lining.

(Effects of the Invention) The foam mortar of the cementitious filler composition of the present invention has a specific gravity of less than 1.0, good fluidity, and easy adjustment of gel time. Furthermore, it exhibits outstanding effects such as no shrinkage after curing and strong adhesive strength after curing. This foam mortar can be produced continuously and has the advantage of being able to continuously pour one span.

Since the above-mentioned foam mortar is used in the existing pipe lining method of the present invention, floating of the renovated new pipe can be prevented by a simple method of filling the renovated new pipe with water. Even if the gap between the existing pipe and the renovated new pipe is narrow or long, foam mortar can be easily injected over the entire gap. The fracture strength of the composite pipe obtained by this method is equal to or greater than the strength of new pipe.

Figure 2 is a graph showing the relationship between specific gravity and fluidity of foam mortar of the composition of the present invention; Figure 3 is a graph showing the relationship between temperature and gel time of foam mortar;
The figure is a cross-sectional view of the sample used in the composite strength fracture test.

10... Outer pipe, 11... Renewed new pipe, 12... Backfilling material.

that's all

Claims (1)

[Claims] 1. A cement-based filler composition containing cement, a foaming agent, a setting modifier, and water, wherein the foaming agent contains higher alcohol sulfonic acid triethanolamine salt and polyvinyl alcohol. and the setting modifier contains an inorganic oxide, and the foaming agent is 0.50 to 0.65 parts by weight and the setting modifier is 7.0 to 8.0 parts by weight based on 100 parts by weight of cement. and water 40
50 parts by weight of a cementitious filler composition. 2. A method for lining an existing pipe, which includes the step of filling and curing the cement-based filler composition according to claim 1 into the gap between the existing pipe and the renovated new pipe inserted therein.