JPH03261678A - Method for curing hydraulic system - Google Patents

Abstract

PURPOSE:To prevent a hydraulic system from cracking and provide a high strength and difficult water absorption by curing an unhardened hydraulic system according to hermetically sealed curing, etc., or air dried curing, rapidly feeding water into water voids when the hydraulic system is not collapsed with water or hot water and curing the resultant system while suppressing evaporation of water. CONSTITUTION:An unhardened hydraulic system after forming is cured while suppressing vaporization and evaporation of water in the hydraulic system itself according to hermetically sealed curing, steam curing, etc., or air dried curing is carried out. When the hydraulic system is not collapsed with water or hot water, insufficient water is collected on the hydraulic system as quickly as possible or intermittently or continuously supplied thereto or the hydraulic system is dipped in the water, hot water, etc., to supply water into water void holes. The hydraulic system is cured while suppressing vaporization and evaporation of water in the hydraulic system itself or further subsequently cured while suppressing the vaporization and evaporation of water in the hydraulic system itself according to hermetically sealed curing, steam curing, etc., without supplying insufficient water thereto.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a curing method for hydraulic systems that is effective in preventing cracks, increasing strength, making water absorption difficult, and the like.

[Prior Art] First, terms used in this invention will be explained. Hydraulic systems are those that react in the presence of water, such as reaction between uncured cement materials such as fresh mortar and fresh concrete, and cured products such as mortar and concrete, or pozzolancemen 1, or siliceous ash reactions. A general term for uncured products and cured products. The efflorescence component refers to water-soluble salts mainly composed of calcium hydroxide that are produced when water is added to cement. The term "deficit water" refers to the insufficient amount of water necessary for a water-iron system to undergo a sufficient hydration reaction or hydrothermal reaction, and includes not only water and hot water, but also the following reaction liquids and lime-based aqueous solutions. J refers to an aqueous solution that reacts with the efflorescence component. Lime-based aqueous solutions are calcium hydroxide, which is made by adding water to hydraulic systems such as cement and mortar, slaked lime, quicklime, or quicklime exposed to the air, and aqueous solutions mainly composed of calcium hydroxide, which are made by adding water to hydraulic systems such as cement and mortar, or by adding water to quicklime exposed to the air. Moist curing or steam curing in a closed room filled with hot water, steam curing by sending steam into a closed room,
High-pressure curing, which uses formwork such as humid pipes or piles, and airtight lids, etc. to seal the product under high pressure, and autoclave curing, which is a curing method that suppresses water evaporation.

In addition, humidity [100% is preferable, but if it is possible to effectively suppress the evaporation of water in the hydraulic system itself, the time for which the degree of sealing is incomplete varies depending on the curing temperature, etc., so is it possible to limit the time? Water is replaced by water or air in the hydraulic system due to evaporation, and the amount of calcium carbonate generated on the inner wall of the water pore is smaller and shallower. Specifically, the temperature is 1
When curing at about 0 degrees, it takes approximately 20 hours, when curing at about 20 degrees, it takes about 15 hours, and when curing at about 35 degrees, it takes about 1 hour.
Within 0 hours, approximately 8 hours when curing at around 45 degrees, 5
When the temperature is about 5 degrees, approximately 6 hours or less is desirable, and the higher the temperature, the shorter the time. However, due to factors such as humidity during curing, the time is not necessarily limited to the above.

Conventionally, as curing methods for hydraulic systems including cement systems, air dry curing, curing using heat from hydration reaction, moist curing, underwater curing, steam curing, autoclave curing, water spray curing, etc. are known.

[Problem to be solved by the invention] The curing methods up to now have neglected the initial curing to avoid the effects of the evaporation of water in the initial stage of the hydraulic system. Cracks were likely to occur.

For example, in the case of W green, the water evaporates before the hydration reaction progresses, and many water borders are formed, resulting in low strength and water absorption.During evaporation, cohesive force acts between cement particles, causing them to shrink and cause cracks. Become.

In water curing, a hydraulic system that has been cured and demolded is cured in water, so a large amount of water is already formed, and gel formation is good and the strength is greater than air dry curing, but it also prevents the elution of efflorescence components. However, it has high water absorption and does not have sufficient strength.

Even if the humidity is 100%, the amount of water in the air in the curing room is small and it is difficult to replenish the water shortage, even if the humidity is 100%. In addition, due to the heat of hydration reaction and the heat storage effect of the formwork, the temperature of the hydraulic system becomes higher than the temperature inside the curing chamber, and the open surface of the hydraulic system, that is, the surface in contact with the air, breaks the 100% humidity state and becomes waterlogged. Hard water evaporates, creating a large amount of water border, which is not only absorbent, but also when the humidity is below 10.0% or the curing temperature is high, water evaporates and evaporates even more, replacing the evaporated water. The carbon dioxide in the air reacts with the efflorescence component, forming a calcium carbonate layer with sparse (or many gaps) on the inner wall of the water pore, which has a low strength compared to the heat energy generated. The presence of calcium carbonate on the inner wall of the water pores inhibits the formation of gel, resulting in not only poor strength but also high water absorption.

In the autoclave curing of ALC, in order to prevent cracks due to expansion of air and debris, the ALC is cured after waiting for about 2 to 24 hours. During this time, water evaporates and forms a water border, which is highly absorbent.

Even with autoclave curing of cement-based hydraulic systems, if the water in the hydraulic system evaporates before curing, or if the balance between pressure and temperature is disrupted and the water in the hydraulic system evaporates and evaporates, sufficient strength may not be obtained. Becomes water absorbent.

Water sprinkling curing is used to cure the hydraulic system after demolding, and not only do many water borders already exist, but also it is a formality (sprinkling water only), and in areas where there is no water or dry areas, the hydraulic system itself may be damaged. The water evaporates and is not very effective.

The object of the present invention is to provide a hydraulic curing method that solves the problems of the conventional curing methods described above.

1. Means for Solving the Problem] In order to achieve the above object, the hydraulic system curing method of the present invention is as follows:
After molding, the uncured hydraulic system is cured by airtight curing or steam curing while suppressing the evaporation of the water in the hydraulic system itself, or air-drying is performed, and once the hydraulic system does not disintegrate with water or hot water, it can be cured as much as possible. Immediately collect the missing water on top of the hydraulic system, or supply the missing water to the hydraulic system intermittently or continuously, or immerse it in water or hot water to supply water into the water pores. It is characterized by curing while suppressing the vaporization and evaporation of the water in the hydraulic system itself, or by curing while suppressing the vaporization and evaporation of the water in the hydraulic system itself, by sealing curing, steam curing, etc. without continuously replenishing insufficient water. .

The method for curing a hydraulic system of the present invention is to cure a hardened hydraulic system while suppressing the evaporation of water in the hydraulic system itself by closed curing or steam curing, etc. Before or during curing,
Replenishing insufficient water to the hydraulic system and curing by supplying water into the water pores after molding and/or after molding, or evaporation of water in the hydraulic system itself without further replenishing the insufficient water. It may also be a curing method in which the skin is cured while suppressing the .

[Function] This invention was made by observing the state until it becomes a saturated aqueous solution when water is added to slaked lime, quicklime, and cement.
At first, the amount of elution is minimal, but after about 5 to 6 hours, it reaches a saturated state, and a porous thin layer of calcium carbonate forms on the surface.When the container is sealed with a lid, leaving a space, the pores are extremely small and dense carbonate is formed. I learned that it is possible to form a thin layer of calcium, and when cement paste is molded to a thickness of 5 mm, it will be 2.5 mm thick in summer.
I learned that it takes about 3 hours, and in winter it takes about 4 to 8 hours to shrink and crack due to the evaporation of water. This was done after realizing that the degree of florescence component 'a' is closely related to the occurrence of efflorescence, strength, and water absorption.

That is, during summer or high-temperature curing, a large amount of water evaporates while the efflorescence component is not eluted, resulting in large diameter and numerous water borders, resulting in low strength and water absorption. In addition, because the migration of efflorescence components to the surface is small, primary efflorescence does not occur, and carbonate carlum adheres sparsely or with a large number of gaps on the inner wall of the water pores, contributing to an increase in strength.

On the other hand, in winter or low-temperature curing, the evaporation rate of water is slow, and the water becomes a saturated aqueous solution of efflorescence components.If the water rapidly evaporates due to temperature changes in the morning and evening, wind, etc., the efflorescence components inside will migrate to the surface. Primary efflorescence occurs when it reacts with carbon dioxide gas. Furthermore, since water evaporates slowly, cement gel (hereinafter simply referred to as gel) is formed more smoothly than at high temperatures. Calcium carbonate adheres to the goose compared to summer and high temperatures,
Water absorption becomes small.

The operation will be explained next with reference to the above phenomenon.

A curing method that involves replenishing the missing water as soon as possible after the uncured hydraulic system does not collapse under water or hot water, supplying water into the water pores that have already been created, and curing while suppressing the evaporation of water in the hydraulic system itself. In this method, a large amount of gel is produced, and the resulting gel extends into the already formed water pores, making the diameter of the water pores smaller. Even if a small amount of water evaporates during curing while reducing water absorption and suppressing water evaporation, a denser layer of calcium carbonate is formed on the inner wall of the water pores, making it difficult to absorb water. Furthermore, if the hydraulic system itself is cured by suppressing the evaporation of water before replenishing the insufficient water, it will have even higher strength and less water absorption, and will have fewer cracks. Furthermore, if the water in the hydraulic system itself is cured by suppressing the evaporation of water without replenishing the insufficient water, a gel is generated during this time, resulting in even higher strength and less water absorption.

In addition, the curing method of replenishing insufficient water before and/or during curing and curing by suppressing the evaporation of water in the hydraulic system itself is difficult when curing after molding because the water edge is small in diameter and has high strength. It absorbs water and is less prone to cracking. Even after curing after demolding, gel will still be generated, so the diameter of the water border that has already been formed can be reduced.If you cure both after molding and after demolding, the product will become even stronger and less absorbent, making it easier to ship the product. It is also possible to accelerate the

In addition, when replenishing a lime-based aqueous solution as a water shortage, the calcium carbonate that comes to the inner wall of the water pore can be made more dense, and when replenishing the reaction liquid, the efflorescence component and the reaction liquid and/or carbon dioxide can be made more compact. React, the reactants make the water border smaller in diameter,
When the reaction liquid is a substance that reacts with an efflorescence component such as an aqueous solution of potassium stearate to create a water-repellent substance (hereinafter referred to as a water-repellent substance), the hydraulic system becomes even more water-repellent. do.

[Example] In the following examples, Portland cement was used as the cement unless otherwise specified. In addition, the number of parts indicates parts by weight.

In steam curing, hot water is placed in a closed curing chamber made of non-ventilated heat insulating material, and the steam is used. In humid curing, water is placed instead of hot water, and in both cases, the hydraulic system is heated with hot water or water. I cured it without soaking it in water.

Example 1 A test piece of 5 parts m x 5 C... x 5 cm was made from green mortar mixed with 400 parts of cement, 1200 parts of sand, and 250 parts of water, and when it was air-dried and cured at a temperature of 27 to 30 degrees, the compressive strength for one week was 163 kg. /cm2 After air-drying at a temperature of 12 to 14 degrees, the 1-week compressive strength is 180 h/cm2
Immediately after molding, steam curing was performed at an ambient temperature of 35 degrees in a closed curing chamber, and the mold was removed after 6 hours, and immediately placed in hot water at 37 degrees for 10 minutes.
Soak for a minute to replenish the missing water, take it out and put it back into the closed curing chamber while wet, and steam cure for 38 hours at an ambient temperature of 35°C while spraying hot water at 37°C every hour to replenish the missing water. After air-drying at a temperature of 17 to 20 degrees, the weekly compressive strength was 289 K (+/cm2).
The compressive strength for one week after curing at a temperature of 20 degrees is 308
Kg/Cm2, and the higher the strength, the harder it was to absorb water.

Example 2 A test piece of 5 cm x 5 cm x 5 cm was made with green mortar mixed with 400 parts of cement, 1200 parts of sand, 200 parts of water, and 4 parts of water reducing agent (Mighty 150 manufactured by Kao Corporation), and was heated at 27 to 30 degrees. The one-week compressive strength of the product air-dried at a temperature of 205 K! The one-week compressive strength of the product air-dried at a temperature of 1.12 to 14 degrees is 221 Kq.
/cm2, Immediately after molding, steam curing was performed at an ambient temperature of 35 degrees in a closed curing chamber, and after 6 hours, the mold was removed, immediately immersed in hot water at 37 degrees for 10 minutes to replenish the missing water, and taken out and sealed again while wet. Placed indoors, steam-cured at an ambient temperature of 35 degrees for 38 hours while spraying hot water at 37 degrees every hour to replenish the water shortage, then air-dry at a temperature of 17 to 20 degrees for one week. The compressive strength was 323 K (J/cm2), and the one-week compressive strength of the samples wrapped in Saran wrap and cured at a temperature of 17 to 20 degrees after steam curing was 341 Kg/cm2, and the higher the strength, the more difficult it was to absorb water.

Example 3 A raw mortar with a cement:sand ratio of 1:2 was press-dehydrated, molded, and air-dried.The 2-week bending strength was 123. 2
Kg/cm2. After 2 days of air dry curing, after 7j, soaked in water for 2 hours, taken out and placed in a wet sealed curing chamber for moist curing 3 times a day, this continued for 8 days. The 2-week bending strength of the product after air-drying was 157K (+/C...
2. The 2-week bending strength of the samples cured by soaking in the reaction solution instead of water was 165.2 Kc+/cm2, and the higher the strength, the more difficult it was to absorb water.

Example 4 A test space of 5 cm x 5 cm x 5 cm was made with green mortar mixed with 400 parts of cement, 1200 parts of sand, and 250 parts of lime water, and the test space was air-dried and cured at a temperature of 27 to 30 cm, and compressed for 2 weeks. Strength is 198K (1 part cm2, immediately after molding, put in a closed curing chamber for moist curing, take out the next day, remove the mold, soak in water for 1 hour, take out, and then put in a wet closed curing chamber for moist curing. This was repeated 3 times a day for 8 consecutive days (afterwards, it was air-dried and cured), and its 2-week compressive strength was 257 Kg/cm2, indicating poor water absorption.

Example 5 A foaming solution was prepared by adding 1 part of a water reducing agent and 1 part of a foaming agent to 100 parts of water, and 34 parts of the foaming solution and 100 parts of cement were kneaded to make a paste. Bubbles made with foam liquid 13
and knead to make a foam-containing paste, 5 cm x 5
Immediately after molding, a test piece of x5 cm was placed in a closed curing chamber and steam-cured at a temperature of 35 degrees, then molded for 6 hours, soaked in hot water at 40 degrees for 1 hour, and then cured in an autoclave.The compressive strength was To 56! ;l/C...2 (specific gravity 0
．． 69>.

In addition, water and aluminum powder are added to appropriate amounts of cement, slaked lime, and silica sand fine powder to foam, placed in a closed curing chamber for 6 hours of moist curing, soaked in hot water at 35 degrees for 30 minutes, and moist curing again every 30 minutes. The material that was sprayed with hot water and cured for 6 hours, and then cured in an autoclave, had less water absorption than conventional ALC. A product made by foaming quicklime or slaked lime and fine silica sand with aluminum powder is also cured as described above to make it difficult to absorb water. It is possible to make the material difficult to absorb or water repellent by impregnating it with a reaction solution before, during, or after curing in the autoclave. It is also possible to reduce the pores, voids, water borders, etc. in the bubble film by curing and reacting while suppressing the evaporation of water.

Although the fifth embodiment has been described above, the present invention can take the following embodiments.

(1) A reaction liquid and/or a lime-based aqueous solution can be used to replace the water shortage, and a water-repellent substance can be used in the reaction liquid.

(2) When making a hydraulic system, it can be made by adding a reaction liquid, and instead of water, a lime-based aqueous solution or a further strengthened reaction liquid can be used.

(3) Closed curing also includes covering curing with non-porous or non-porous heat insulating materials.

(4) To collect water on top of the hydraulic system, it is also possible to lower the top surface of the hydraulic system from the top of the formwork, pour the hydraulic system, and use the formwork to collect water. .

(5) As the cement, fly ash cement, palm silica cement, blast furnace cement, white cement, moderate heat cement, etc. can be used.

(6) The reaction solution includes various acids that react with the efflorescence component, alkalis such as water glass, baking soda, or aqueous ammonia, silicas such as silica sol, silicon, microsilica, and silica hume, potassium stearate, sodium stearate, etc. Water-repellent substances, water-reducing agents, fluidizers, thickeners, etc. (commercially available concrete additives) can be used as long as they react with the efflorescence component in the presence of water. For types, use a dilution solution of about 1/1 million to 1/10 million, for carboxylic acids, use a dilution solution or solution of about 1/2 million to 11.5 million, and for alkalis, use a dilution solution of about 1/100 to 1/10 million.
A diluting solution or dissolving solution of about 200,000 can be used, and a diluting solution of about 1 to 1/200 can be used for silicas, water repellency imparting substances, or various additives.

(7) The curing temperature is preferably a temperature at which the air expansion in the hydraulic system (thus, the tissue is not destroyed and the rate of water evaporation is relatively slow, preferably 40 degrees Celsius or below);
Once the hardening progresses and the tissue is no longer destroyed, the temperature may be raised to preferably about 60 degrees for curing. In addition, if the tissue is not destroyed by vaporization of water, or if high pressure curing or autoclave curing is performed, curing may be performed at a temperature of 60 degrees or higher. Also, when curing the temperature, it is quite effective even at around 500 degrees, but preferably at 1000 degrees or higher.
Curing at around 000 degrees is desirable. For example, initially/! 40
If the product is cured for 12 hours at 60 degrees Celsius and then 24 hours at 60 degrees Celsius, it will be cured at 1920 degrees Celsius, and can be shipped immediately after curing in two days.

(8) If an object or method used in one embodiment is appropriate for other embodiments, it can be used, utilized, or applied to other embodiments.

[Effects of the Invention] The curing method of the hydraulic system of this invention is configured as described above, and by controlling the supply of insufficient water, it is possible to freely control the increase in strength and/or the reduction in water absorption, and the curing method is also simple. Not only is it economical, but if the hydraulic system is cement-based, the amount of cement used can be saved if the same strength is to be obtained, and the hydraulic system, which has become difficult to absorb water, will retain its internal alkaline content. Therefore, it has effects such as excellent durability, and can be widely used not only for manufacturing secondary concrete products but also for on-site construction work, civil engineering work, etc.

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Claims (2)

[Claims] (1) After molding, the uncured hydraulic system is cured by closed curing or steam curing while suppressing the evaporation of the water in the hydraulic system itself, or air-drying is performed so that the hydraulic system is not exposed to water or hot water. When it stops collapsing, it can be done. Immediately collect the missing water on top of the hydraulic system, replenish the missing water intermittently or continuously into the hydraulic system, or put it in water or hot water. After soaking, supply water into the water pores, and cure while suppressing the evaporation of water in the hydraulic system itself, or use closed curing or steam curing without continuing to replenish the water shortage. A curing method for hydraulic systems that is characterized by curing while suppressing the evaporation of water in the hard system itself. (2) When curing a hardened hydraulic system by airtight curing or steam curing, etc. while suppressing the evaporation of water in the hydraulic system itself, before and/or during curing, Supplying insufficient water to the hydraulic system and curing by supplying water into the water pores after molding and/or demolding, or replenishing the water in the hydraulic system itself without further replenishing the insufficient water. A hydraulic curing method that is characterized by curing while suppressing the vaporization of water.