JPH08155938A - Production of concrete pipe - Google Patents

Abstract

PURPOSE: To impart excellent load resistance to a concrete pipe while achieving the reduction of raw material cost, to shorten the reactive curing time of the concrete pipe by efficiently discharging internal water at the time of production and to extend the life of the concrete pipe. CONSTITUTION: A fiber material having alkali resistance and acid resistance is cut into staple fiber yarns with a length of about 8mm and long fiber yarns with a length of about 20mm or more while water is sprinkled over the fiber material and the cut fiber yarns are dehydrated so that water content becomes about 15-20% to form fiber yarn aggregate. The fiber yarn aggregate is added to water in an amt. of about 1-3% by wt. of cement milk to be prepared to be stirred and cement, sand and, if necessary, aggregate are added to the fiber yarn aggregate in such a state that staple and long fiber yarns are almost uniformly mixed to be mixed therewith under stirring to obtain cement milk. The cement milk is charged in a form having a space part almost coinciding with a desired pipe shape to be cured and reacted while excessive water is drained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a concrete pipe.

[0002]

2. Description of the Related Art Conventionally, in a fume pipe known as a large-sized concrete pipe, in a cylindrical form frame in which cage-shaped assembled reinforcing bars are set, Cement milk is added while rotating the mold at a predetermined rotation speed, and water contained therein is drained by centrifugal force to compact the cement component to produce a concrete pipe having excellent load resistance.

For this type of concrete pipe, cement milk having a low water-cement ratio is used because it must withstand a high internal pressure and an external pressure, and excess water is efficiently drained when the form is charged into the pipe, thereby increasing the cement content. However, the conventional manufacturing method has the following problems.

First, when the water-cement ratio is lowered, there is a problem that the ratio of cement and the like increases and the material cost increases significantly. Secondly, since it is necessary to rotate the mold at a high speed in order to efficiently drain the excess water, there is a problem that the manufacturing apparatus itself becomes large and costly. For this reason, it has been unavoidable to increase the cost of the method for manufacturing the concrete pipe.

Further, in the conventional concrete pipe,
It is difficult to efficiently drain the water that has penetrated into the concrete, and the service life is deteriorated by corroding the steel rods that are accumulated inside and alkalized by the cement component or acidified by sulfurous acid gas in the air to corrode the built-in rebar. I also have.

The present invention was invented in order to solve the above-mentioned conventional drawbacks, and an object of the invention is to produce a concrete pipe excellent in load bearing capacity while reducing raw material costs. To provide.

Another object of the present invention is to provide a method for producing a concrete pipe which can efficiently discharge internal water during production to shorten the reaction hardening time.

Still another object of the present invention is to provide a method for manufacturing a concrete pipe which can prolong the service life.

[0009]

For this reason, the invention of claim 1 provides a short fiber yarn of about 8 mm and a long fiber yarn of about 20 mm or more while sprinkling water on a fiber material having alkali resistance and acid resistance. After cutting each of them to form a fiber yarn assembly by dehydration so that the water content becomes about 15 to 20%,
About 1 to 3 relative to the weight of cement milk to be adjusted
Cement and sand and, if necessary, aggregates are added in a state where the short-fiber yarn and the long-fiber yarn are agitated so that the weight-fiber aggregate is added to be substantially uniform, and the mixture is agitated to obtain cement milk. It is characterized in that it comprises a process and a process in which cement milk is put into a mold having a space portion that substantially matches a desired pipe shape and a curing reaction is performed while draining excess water contained therein.

Further, in the invention of claim 2, the water content of the fiber material having an alkali resistance and an acid resistance is reduced while being cut into short fiber yarns of about 8 mm and long fiber yarns of about 20 mm or more while spraying water. After the fiber yarn aggregate is formed by dehydration to about 15 to 20%, the fiber yarn aggregate of about 1 to 3% by weight relative to the weight of the cement milk to be adjusted is added to water to make a short fiber yarn aggregate. The process of obtaining cement milk by adding cement and sand and aggregate, etc., if necessary, in a state where the fiber yarn and the long fiber yarn are agitated to obtain a cement milk is almost the same as the desired pipe shape. A step of accommodating a reinforcing member assembled in a cage shape in a formwork having a space part, and a hardening reaction while putting cement milk into the formwork in which the reinforcing member is set and draining excess water contained It is characterized by consisting of ing.

[0011]

Embodiments of the present invention will be described below.

Claim 1 First, a method for preparing cement milk will be described.

Cement milk is generally cement,
The cement milk of the present invention is obtained by mixing sand and, if necessary, aggregate with water, and long-fiber yarn and short-fiber yarn are added to the cement milk.

The long fiber yarn and the short fiber yarn are obtained by cutting the following fiber materials having alkali resistance and acid resistance such as acrylic yarn and polyester yarn.

The above-mentioned fiber material such as acrylic yarn is used as a raw material for carbon fiber, and the one that is discharged and discarded when cut into a predetermined length before firing is not uniform in length. By using it, the raw material cost is reduced. Then, the fiber material having an uneven length obtained as described above is cut into a single fiber yarn of about 8 mm and a long fiber yarn of about 20 mm or more by a cutting device such as a shear. At the time of this cutting, water is sprayed to prevent scattering.

The long fiber yarn and the short fiber yarn cut into the respective lengths as described above are adjusted and mixed such that the former is 70% or more of the whole and the latter is 10% or less of the whole. It The mixed and adjusted long-fiber yarns and short-fiber yarns have a water content of about 15 by a dehydrator.
It is dehydrated to -20% to form a fiber yarn aggregate.

When the cement milk is prepared, the fiber yarn assembly obtained as described above is added to a predetermined amount of water.
About 1 to 3% by weight of the cement milk weight to be adjusted
Cement milk is prepared by adding the above-mentioned cement, sand and, if necessary, aggregate and the like to the above mixture and stirring and mixing.

The above-mentioned cement milk is put into a mold rotating at a predetermined speed and reacted and hardened. The mold has a substantially cylindrical shape and is composed of an outer frame and an inner frame which are multi-dividable and are arranged concentrically with a predetermined thickness width. In addition, the rotational speed of the mold is the centrifugal force applied to the cement milk that is input,
Desirably, it is set to be about 35 to 50 kg / cm ² .

Then, the cement milk put into the mold is compacted by cement, sand, aggregates added as needed, and long fiber threads and short fiber threads while draining the excess water by the centrifugal force. . At this time, the long fiber yarn and the short fiber yarn are entangled with each other due to the compacting action.

When the cement milk is cured to a certain degree of hardness in the mold, the mold is divided and taken out to manufacture a concrete pipe. This concrete pipe has its strength increased as a result of its cement component being compacted, but it is further strengthened by the interlocking of the added long fiber threads and short fiber threads.

The uncured concrete pipe taken out of the mold retains water inside, but the long and short fiber threads that are entangled with each other and exposed on the outer surface are soaked in water and drained. It is possible to shorten the curing time.

Further, at the time of use, water such as rainwater is soaked into the concrete pipe. The water soaked into the interior is alkalized by the cement component or acidified by sulfurous acid gas in the air to weaken the cement component, but in the concrete pipe of the present invention, long fibers entangled with each other. The water soaked in by the yarn and the short fiber yarn can be drained, and the service life can be extended.

According to claim 1, the concrete pipe is manufactured by directly adding cement milk into the mold and curing it.
The concrete pipe of claim 2 is manufactured by incorporating a reinforcing bar inside.

That is, basket-shaped knitted reinforcing bars are preset in the mold into which the cement milk is put. This cement milk is the same as that described in the embodiment of claim 1, and its detailed description is omitted.

Then, when the cement milk is added while rotating the formwork on which the reinforcing bars are set at a rotation speed corresponding to a desired centrifugal force, the cement milk is drained of excess water by the centrifugal force which acts, and the cement The components (cement, sand, aggregate, long fiber yarn and short fiber yarn) are compacted and allowed to undergo a curing reaction. At this time, the contained long fiber yarns and short fiber yarns are intertwined with each other and also with the built-in reinforcing bars.

For this reason, the concrete pipe taken out from the mold after the curing reaction has the compacted cement component, the long fiber yarn and the short fiber yarn which are intertwined with each other and intertwined with the rebar, and are made of concrete according to claim 1. It is made stronger than the pipe. Further, as in the case of the concrete pipe according to claim 1, excess water in the inside can be impregnated into the long fiber yarn and the short fiber yarn intertwined with each other and drained to the outside, thereby shortening the curing reaction time and corroding the reinforcing bar. Can be suppressed to prolong the service life.

[0027]

Therefore, according to the present invention, the load resistance can be improved while reducing the raw material cost.

Further, according to the present invention, the water inside can be efficiently discharged at the time of production to shorten the reaction curing time. Further, the present invention can prolong the service life.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display area // (C04B 28/02 16:06 Z 14:02) Z

Claims (5)

[Claims] 1. A water content of about 15 to 20% after being cut into short fiber threads of about 8 mm and long fiber threads of about 20 mm or more while spraying water on a fiber material having alkali resistance and acid resistance.
To form a fiber yarn aggregate, and then add about 1 to 3 wt% of the fiber yarn aggregate to water to the weight of the cement milk to be adjusted to add short fiber yarn and long fiber. With the process of adding cement and sand and aggregates, etc., if necessary, while stirring so that the threads become almost uniform, and stirring and mixing to obtain cement milk, there was a space part that almost matched the desired pipe shape. A method for producing a concrete pipe, comprising the steps of introducing cement milk into a mold and causing a curing reaction while draining excess water contained therein. 2. A water content of about 15 to 20% after being cut into short fiber threads of about 8 mm and long fiber threads of about 20 mm or more while spraying water on a fiber material having alkali resistance and acid resistance.
To form a fiber yarn aggregate, and then add about 1 to 3 wt% of the fiber yarn aggregate to water to the weight of the cement milk to be adjusted to add short fiber yarn and long fiber. With the process of adding cement and sand and aggregates, etc., if necessary, and mixing to obtain cement milk while stirring so that the threads are almost uniform, and a space part that substantially matches the desired pipe shape It consists of the step of accommodating the cage-shaped reinforcing member in the formwork, and the step of introducing cement milk into the formwork in which the reinforcing member is set and causing the hardening reaction while draining the excess water contained. Manufacturing method of concrete pipe. 3. The method for producing a concrete pipe according to claim 1, wherein the fiber material is an acrylic thread or a polyester thread. 4. The fiber yarn assembly is prepared such that about 70% or more of monofilament yarns each having a length of about 8 mm and about 10% or less of the filament fiber yarns each having a length of about 20 mm or more are prepared. Item 1. A method for producing a concrete pipe according to item 1 or 2. 5. The method for producing a concrete pipe according to claim 1, wherein when the cement milk is put into the form, the form is rotated at a predetermined rotation speed so that the cement component can be compacted by centrifugal force. Method.