KR0162972B1 - Polymer concrete of a tube - Google Patents

Abstract

1. TECHNICAL FIELD OF THE INVENTION

The present invention relates to a sewage pipe using polymer concrete used for sewage.

2. The technical problem to be solved by the invention

Conventional sewage pipes have been mainly used for cement concrete pipes, earth pipes or plastic pipes, but sewage pipes, such as inorganic cement concrete pipes, are weak to acidic or alkaline substances mixed in the sewage and are easily corroded and broken. The sewage pipe was weakly damaged by external pressure unless the reinforcing core was inserted between the inner skin and the outer shell.The pipe with the reinforcing core inserted was not used much except in certain fields because of its high manufacturing cost. It was.

3. Summary of Solution to Invention

In order to solve the above problems, in the present invention, the unsaturated polyester resin binder 10 to 16% (w) containing 10 to 20% (w / w) of shrinkage reducing agent with respect to the binder using an unsaturated polyester resin having strong corrosion resistance / w), 60 to 80% (w / w) of aggregates such as sand, silica sand, gravel, and fly ash, calcium carbonate or stone powder 20 to 25% (w / w) as fillers, and an appropriate amount of initiator and generally A polymer concrete composition composed of 0.1 to 0.6% (w / w) of crosslinking agent used was put into a centrifugal force forming mold to prepare a circular tube by centrifugal force, and then superficially By coating unsaturated polyester resin, it is possible to provide a sewer pipe having high corrosion resistance to chemicals while maintaining high strength.

4. Important uses of the invention

The centrifugal force pipe according to the present invention can be used not only for sewage but also for use as a related waterway in rural areas.

Description

Sewage Polymer Concrete Centrifugal Tube

1 is a partially cutaway perspective view of a centrifugal force tube according to the present invention.

* Explanation of symbols for the main parts of the drawings

S, S ': Corrosion-resistant resin lining layer

C: Allo type polyester resin layer

The present invention relates to a centrifugal force tube, and more particularly, to a sewage polymer concrete centrifugal force tube having a significantly improved corrosion resistance against various erosive contaminants introduced into the tube, as well as a load capacity for various external loads, using a polymer composite as a main material. will be.

In recent years, due to the rapid development of secondary industry, with the explosive increase in traffic along with erosive sewage and wastewater discharged from various factory facilities, the amount of various pollutants mixed with rainwater and entering the sewage system is also greatly increased. Is on the rise.

In particular, the sewage system in Korea is composed of the integrated treatment system of sewage and rainwater, which causes serious problems such as soil pollution, groundwater pollution and crop contamination as well as soil contamination when sewage pipes are damaged and the sewage and wastewater leak. .

This problem can be solved by using a sewage pipe having excellent strength characteristics and corrosion resistance at sewage construction, and preventing leakage of sewage and waste water caused by damage or damage to the sewage pipe by various external pressures or erosive materials.

However, the centrifugal compacted reinforced concrete pipe, called Humepipe, is one of the various sewage pipes used in the related art. Chemical resistance also has a very weak problem.

In addition, the vibration and voltage reinforced concrete pipes are insufficient in strength and durability and have high absorption rate, so if the fill height is low when buried, there is a high risk of freezing in winter, and there is a weak point to acid and base.

In addition, due to the hardening characteristics of the concrete tube described above, high strength curing is required for long time, so that the turnover of the formwork used in manufacturing is low and the productivity is lowered. It also has a costly disadvantage.

In addition, iron pipes made of galvanized steel, etc., have a problem of being extremely weak against corrosion as well as floating when the groundwater level is high due to lack of self-weight, and synthetic resin pipes and conduits have been widely used as conventional sewer pipes. As a result, synthetic resin pipes tend to be distorted by external pressure, and in the case of conduits, they cause brittle fracture, and thus are not suitable for large pipes.

As can be seen from the above, conventional sewage pipes manufactured from reinforced concrete, steel, or synthetic resins have many problems in load resistance and corrosion resistance.

These various problems have high tensile, flexural and compressive strengths, excellent resistance to freeze-thawing, watertightness, and chemical resistance to various erosive chemicals, and a short curing time during manufacturing to increase productivity. This can be solved by replacing the sewage material with polymer concrete.

Polymer concrete may be prepared by mixing a thermosetting resin such as unsaturated polyester resin, epoxy resin, vinyl ester resin, or polymethyl methacrylate (MMA) as aggregate, together with aggregate, filler and various additives.

Since the above-mentioned thermosetting resin for binders is relatively expensive, it is very important to determine the blending ratio that minimizes the content ratio of the polymer binder and maximizes the content ratio of the aggregate and the filler under the range of high strength properties. .

In addition, in the selection of polymers, it is advantageous to use unsaturated polyester resins that are not only about 1/2 to 1/3 cheaper than other resins such as epoxy resins but also have excellent physical and chemical properties. Among the ester resins, it is more preferable to use an Orto type unsaturated polyester resin which is much cheaper than other types of unsaturated polyester resins.

As described above, the polymer concrete has an optimum compounding ratio for expressing its properties according to its use, and the types of materials added together vary according to the properties of the polymer used as the binder. The design method is not clearly identified.

In particular, the unsaturated polyester resin exhibits a large shrinkage of 3 to 7% when cured, and thus it is difficult to guarantee the stability of the dimension when the sewer pipe is manufactured from polymer concrete using the binder as a binder. When the amount of shrinkage reducing agent is excessive, there is a problem such as a sharp decrease in strength.

The inventors of the present invention, the amount of shrinkage reducing agent for expressing high strength properties, etc. of the Republic of Korea Patent Application No. 95-44208, the content of the shrinkage reducing agent used in the production of unsaturated polyester polymer concrete is 10 to 20% of the unsaturated polyester polymer resin binder ( (w / w) has been filed for a composition of polymer concrete that finds the most suitable and has high strength properties.

The present invention derives an appropriate blending ratio of filler and aggregate used with the shrinkage reducing agent based on the content ratio, and provides a high strength, waterproof and durable centrifugal polymer concrete centrifugal pipe by compacting the centrifugal force. There is a purpose.

Generally, polymer concrete is composed of resin and coarse aggregate, fine aggregate, filler, reaction initiator and crosslinking agent used as a binder, but in the centrifugal force polymer concrete according to the present invention, addition of coarse aggregate is not necessarily necessary, and when the thickness is thin It is advantageous not to use it.

In the present invention, the unsaturated polyester resin binder 10 containing 10 to 20% (w / w) shrinkage reducing agent for the binder based on the mixing ratio determination method according to the minimum pore theory to prepare unsaturated polyester polymer concrete To 16% (w / w), 60 to 80% (w / w) of aggregates such as sand, silica sand, gravel, and fly ash, calcium carbonate or stone powder 20 to 25% (w / w) as a filler, and an appropriate amount By preparing a polymer concrete composed of 0.1 to 0.6% (w / w) of the initiator and a commonly used crosslinking agent, it was possible to produce a polymer concrete centrifugal force tube meeting predetermined strength characteristics by compacting by centrifugal force.

The shrinkage reducing agent mentioned above is a thermoplastic polystyrene dissolved in a styrene monomer. When more than 20% (w / w) of the total binder weight is added, the shrinkage reducing agent decreases the cohesive density of the unsaturated polyester resin after curing to reduce the strength of the polymer concrete. If the addition is less than 10% (w / w) it will have a large effect, 10 to 20% (w / w) of the total weight of the binder is most suitable because the effect of reducing shrinkage as intended.

The unsaturated polyester resin used as a binder by mixing with the shrinkage reducing agent is added with cobalt octanoate (CoOc), a cobalt-based curing accelerator, and an ortho type unsaturated polyester which causes a curing reaction by an initiator. As resin, the structural formula is as following (1) Formula.

If it is used up to about 8% of the total weight of polymer concrete, the strength increases with the increase of the weight ratio, but if it is more than 12%, the separation, shrinkage, warpage, etc. of the resin not only increase, but also the workability of stirring and forming decreases significantly. The weight ratio of the reducing agent, the curing accelerator and the binder composed of the unsaturated polyester resin is 10 to 16% is most suitable.

In addition, the filler may be used in general, all the filler used in the plastic processing field. Fillers include calcium carbonate, stone powder, fly ash, titanium dioxide, and the like, but fillers such as titanium dioxide are expensive compounds and are relatively inexpensive because they do not exhibit particular effects in the present invention. Suitable.

Among calcium carbonates, heavy calcium carbonate is more preferable, and when the addition ratio is 25% (w / w) or more, the viscosity becomes high, and the workability is worsened, and the strength after curing is lowered, so that 20 to 25% (w) / w) is suitable.

It is more preferable that the particle size of calcium carbonate is 1 to 30 µm, the degree of powder is 2500 to 3000 cm ² / g, and the moisture content is less than 0.1%.

In addition, the fine aggregate used as aggregate for the manufacture of polymer concrete centrifugal force tubes should not contain organic impurities and need to be dried to prevent the formation of a water film between the binder layer surrounding the aggregate and weakening the adhesion between the binder and the aggregate. The amount used is preferably 60 to 80% (w / w) in consideration of the strength after curing.

In general, the polymer concrete in the present invention may be used both crosslinking agents used in unsaturated polyester, but because the bond between the organic polymer matrix and the inorganic aggregate has a defect that weakens the chemical adhesive force as a crosslinking agent to solve this problem Silane is used.

However, sewage pipes manufactured using such oxotype unsaturated polyester polymer concrete have high load capacity against external pressure and have relatively good chemical resistance compared with conventional cement concrete, but oxotype unsaturated polyester resin Since it has a relatively weak property in comparison with other resins in resistance to alkaline substances, when manufacturing sewage pipes using this, when alkaline factory wastewater flows into sewage pipes or when sewage pipes are embedded in strong alkaline soils, As time goes by, the inner and outer surfaces of the sewer pipes gradually become corroded, which causes a problem of damage to the sewer pipes.

The present invention solves various problems in terms of strength characteristics of sewage pipes that have been used in the prior art by using unsaturated polyester polymer concrete having an optimum blending ratio identified by the inventors as described above in the manufacture of sewage pipes. At the same time, it is the ultimate in providing polymer concrete centrifugal force pipes for sewage pipes to solve the weak corrosion resistance against alkaline substances, which is a disadvantage of the unsaturated polyester polymer concrete sewer pipes thus produced, and to express high corrosion resistance and excellent corrosion resistance to various chemicals. There is a purpose.

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

FIG. 1 is a partially cutaway perspective view of the present invention. The present invention relates to a center layer (C) and a center layer (C) prepared by compacting polymer concrete produced within the above-described optimum mixing ratio in a centrifugal force molding mold. It is characterized by consisting of a corrosion-resistant resin lining layer (S) (S ') formed on the inner and outer surfaces.

As can be seen from Structural Formula (1), the Ortho type unsaturated polyester resin has many ester groups in its molecular structure, so that it is easy to chemically invade, so that the polymer resin having high corrosion resistance is formed on the inner and outer surfaces of the sewer pipe. The above problems can be solved by lining or gel coating treatment, and it is more advantageous to use the same type of unsaturated polyester resin as the polymer resin in terms of securing adhesion between layers.

Unsaturated polyester resins having such high corrosion resistance include iso type, bisphenol type and vinyl ester type, and the structural formulas are represented by the following formulas (2), (3) and (4), respectively. )

The isotype unsaturated polyester resin of the above formula (2) has the same number of ester groups as the allotype unsaturated polyester resin but has a three-dimensional molecular arrangement, so that the steric hindrance is increased, so that the compound penetrates structurally. It serves to prevent, and particularly has excellent corrosion resistance to non-oxidizing acid, low concentration oxidizing acid, acid salt solution, petroleum up to about 60 ℃.

In addition, the bisphenol-type unsaturated polyester resin of the above-mentioned structural formula (3) has less ester group than the olso-type polyester resin, and weak alkaline aqueous solution up to 90 ° C, various acids and basic salts due to chemical resistance of bisphenol skeleton. It exhibits high corrosion resistance in aqueous solutions and organic solvents, and the vinyl ester type unsaturated polyester resin of Structural Formula (4) is completely uniformly cured at terminal double bonds, so that the chemical resistance is very high. It will have high corrosion resistance.

In addition, an epoxy resin other than the above-mentioned unsaturated polyester resin of the said type shows the same super corrosion resistance.

The ultra-corrosion-resistant unsaturated polyester resin and epoxy resin are lined or gel-coated with a constant thickness on the inner and outer surfaces of centrifugal force tubes made of allo-type unsaturated polyester polymer concrete, so that the load resistance to various external loads is very high. It is possible to manufacture centrifugal force tubes which are high and have excellent chemical resistance against various chemical substances.

Polymer Concrete Production Example

160 kg of the binder prepared by using a 20% (w / w) shrinkage reducing agent among the cobalt octane and unsaturated polyester binders, 126 kg of heavy calcium carbonate, 600 kg of sand sufficiently dried to remove organic matter, and standard As a curing initiator, 1.6 kg of MEKPO (DMP solution containing 55% methyl ethyl ketone prooxide) and 1.6 kg of silane, prepared by Aekyung Chemical Co., Ltd. in Korea, were put in a forced mixer and mixed for 5 minutes to prepare unsaturated polyester polymer concrete. Prepared.

Example 1

4.1 kg of the polymer concrete prepared from the polymer concrete production example was placed in a centrifugal force molding mold having a mold size of Ø20 × 30 cm and a mold tire diameter of 35.9 cm, and the tube body was formed by compacting the centrifugal force while rotating at a speed of about 700 rpm for 15 minutes. This was cured for 7 days while maintaining a temperature of 20 ± 3 ℃ and a relative humidity of 50 to 60%. This process was repeated two more times to prepare three unsaturated polyester polymer concrete centrifugal tubes having a thickness of 1.0 cm, an outer diameter of 20 cm, and a length of 30 cm.

[Examples 2 to 10]

In Example 1, the amount and thickness of the unsaturated polyester polymer concrete injected into the centrifugal force molding mold were changed as shown in Table 1 below, and each of the unsaturated polyester polymer concrete centrifugal force tubes having an outer diameter of 20 cm and a length of 30 cm was selected for each thickness. Dogs were prepared one by one, and the average values of the test results are shown in Table 2.

[External pressure strength test example]

Each centrifugal force tube specimens prepared from Examples 1 to 10 were loaded at a rate of 20 kgf / sec using an ELE digital stress gauge according to the external pressure strength test method specified in KS F 4404 (Rubberless Concrete Tube). The failure load when the centrifuge tube specimen was destroyed was measured. In addition, strain gauges installed on the upper and lower sides of the centrifuge tube test body and LVDTs installed on the inside of the centrifugal force tube are connected to the data logger of San-ei, and the horizontal tensile strain rate is 500kgf for each load. And the strain on the vertical tensile side was measured, and the average value repeated three times for each Example is shown in Table 2 below.

In the test, the centrifugal force test specimen was placed horizontally on the pedestal, and a rubber plate having a thickness of 2 mm and a box of 1.5 × 1.5 × 3 cm were installed on the upper and lower portions of the test specimen, and the test specimen was placed between the rod placed on the upper part of the test specimen and the load cell. An H-beam with the same length as was installed so that the vertical load applied from the load cell was distributed almost uniformly on the test specimen.

As shown in the test results, the polymer concrete centrifugal force tube according to the present invention can be seen that the external pressure strength increases linearly as the thickness increases, and also the vertical displacement and the horizontal and vertical tensile strain on the external pressure load are linear. It can be seen that the decrease.

In order to compare the strength characteristics of the polymer concrete centrifugal tubes presented in the present invention, the external pressure strengths of various cement concrete tubes, namely, reinforced concrete tubes and centrifugal reinforced concrete, as defined in KS F 4401, KS F 4403 and KS F 4404 External pressure strength standards of pipes and plain concrete pipes are shown in Table 3 below.

The external pressure strength of the polymer concrete centrifugal force pipe of the present invention having an inner diameter of 162 mm and a flesh thickness of 19 mm, as shown in Example 10 of Table 1 and Table 2, was 5,148 kgf / m, and the inner diameter shown in Table 3 was 150 mm. Although the inner diameter is much larger than the existing pipes with flesh thickness of 24mm to 26mm, the thickness is much thinner, and despite the absence of any reinforcing material, it shows high strength about 2 to 5.7 times higher than the KS external pressure standard of the existing pipes. It can be seen.

The present invention solves various problems in strength characteristics of sewage pipes which have been conventionally used by using unsaturated polyester polymer concrete having an optimum blending ratio as described above for the production of sewage pipes, and at the same time, unsaturated unsaturated It solves the weak corrosion resistance against alkaline material which is a disadvantage of polyester polymer concrete sewage pipe, and provides polymer concrete centrifugal sewage pipe with high strength and light weight and excellent corrosion resistance to various chemicals. It is a useful invention that can prevent serious underground environmental pollution.

Claims (7)

10 to 16% (w / w) of unsaturated polyester resin binder containing 10 to 20% (w / w) shrinkage reducing agent relative to the binder, and 60 to 80% (w / w) aggregate such as sand, silica sand and gravel w), 20-25% (w / w) of fly ash calcium carbonate or stone powder as a filler, and 0.1 to 0.6% (w / w) of an appropriate amount of initiator and a commonly used crosslinking agent. A method for producing a centrifugal force tube, comprising: preparing a circular tube by centrifugal force in a molding mold, and then coating a super corrosion resistant unsaturated polyester resin on the inner and outer surfaces of the centrifugal tube by spraying or gel coating. In a centrifugal force pipe made of a synthetic resin as a binder, the inner layer (C) of the compaction pipe is made of polymer concrete made of an osol-type unsaturated polyester, and the outer layer (S) (S ') is made of an unsaturated polyester resin having high corrosion resistance. Centrifugal force tube characterized in that the lining treatment. The method of claim 2, wherein the composition of the polymer concrete constituting the inner layer is 10 to 16% (w / w) unsaturated polyester resin binder containing 10 to 20% (w / w) shrinkage reducing agent relative to the binder, 60 to 80% (w / w) aggregate of sand, silica sand, gravel, etc., 20 to 25% (w / w) of fly ash, calcium carbonate or stone powder as a filler, and an appropriate amount of initiator and 0.1 to generally used crosslinking agent. Centrifugal force tube, characterized in that it consists of 0.6% (w / w). The centrifugal force tube according to claim 2 or 3, wherein the super corrosion resistant unsaturated polyester constituting the outer layer is an iso type unsaturated polyester. The centrifugal force tube according to claim 2 or 3, wherein the super corrosion resistant unsaturated polyester constituting the outer layer is a bisphenol type unsaturated polyester. The centrifugal force tube according to claim 2 or 3, wherein the super corrosion-resistant unsaturated polyester constituting the outer layer is a vinyl ester type unsaturated polyester. The centrifugal force tube according to claim 2 or 3, wherein the super corrosion resistant resin forming the outer layer is an epoxy resin.