KR960011320B1 - Method for cement composite material of lightweight using steelmesh and steel fiber - Google Patents

Abstract

The process for producing a cement composite of lightweight foam comprises adding and mixing 0.5-4.0 vol.% carbon fiber as a primary reinforcing material to a cement matrix containing a mixed solution of 0.001-0.005 wt.% water reducing agent(water reducing agent/binder, binder = cement + silica fume), 0.001-0.005 wt.% air carrying agent(air carrying agent/binder) and 0.05-0.3 wt.% silica fume(silica fume/binder), which are dissolved in 0.3-0.4 wt.% mixed water(mixed water/binder); and molding and dehydrating while adding 0.1-2.0 vol.% steel materials as a secondary reinforced material.

Description

Manufacturing method of carbon fiber and steel reinforced lightweight foam cement composites

1 is a graph showing changes in specific gravity, flexural strength and compressive strength according to the content of air entrainer in carbon fiber reinforced lightweight foam cement composites.

FIG. 2 is a graph showing changes in flexural strength, compressive strength and specific gravity according to the change of silica fume content in cement composites.

3 is a graph showing the changes in flexural strength, compressive strength and specific gravity of the molded body according to the carbon fiber content change in the carbon fiber reinforced lightweight foam cement composite.

Figure 4 is a graph showing the flexural load-deflection according to the change of steel content in cement composites with carbon fiber and steel (steel mesh) reinforcement lightweight.

5 is a graph showing the flexural load-deflection according to the change of steel content in carbon fiber and steel (steel fiber) reinforced lightweight foam cement composites.

The present invention relates to a method for manufacturing a lightweight foam cement composite material used for building materials, and more particularly, after the carbon fiber as the primary reinforcing material to align the three-dimensional random (RANDOM) orientation and entrain air The present invention relates to a method for producing carbon fiber and steel reinforced lightweight foam cement composites containing steel as a secondary reinforcing material.

Recently, in the case of concrete structures, there is a demand for rationalization of structures and constructions according to the trend of higher layers, and development of lightweight and high-strength concrete hardeners capable of meeting such demands is required. In accordance with this trend, advanced countries are trying to drastically reduce construction costs by using ALC (AUTOCLAVED LIGHTWEIGHT CONCRETE), which is a lightweight member, for steel framed buildings.

As a means of lightening the concrete, it is common to use lightweight aggregate or entrain air bubbles, and in particular, entraining air bubbles is effective to achieve low specific gravity of 1.5 or less, but ALC is a representative light weight member manufactured using such air entrainment. Recently, ALC is widely used as a stable building material. The manufacturing method of ALC manufactures preformed products by heat-treating cement moldings in an autoclave under high temperature and high pressure. Calcium Silicate Hydrate, called Tobermorite, is produced. Such lightweight composites can be categorized into two types: post-foam process and pre-foam process. In the post-foam process, hydrogen is generated by the interaction between the aluminum powder (powder) added to the cement mixture and an alkali component such as cement or lime (lime) by placing the cement slurry in a mold and then performing heat treatment. To form a cement hardener containing a lot of bubbles inside. This process has a disadvantage that it is difficult to manufacture a large and complicated panel (Panel), as well as a special mold to be used.

Therefore, in order to solve this problem, after the reaction between the aluminum powder (powder) and the alkali component in the slurry in advance to inject bubbles (US Pat. No. 3,551,174), or directly blow air into the slurry (US Pat) No. 3,979,217) A pre-foam process for uniformly dispersing bubbles with a bubble stabilizer and introducing the slurry into a mold has been proposed. However, the above methods have a disadvantage in that a large amount of equipment cost is required by using special equipment, and a gas generator having a size is used to obtain specific gravity of the pores. In addition, after adding the air entrainer, a method for producing a cement composite with a light weight by inducing air entrainment by mixing (US Pat. No. 4,683,003) has been proposed, but a lightweight foam cement composite according to such a method In general, 10% entrained air reduces the specific gravity of the cured concrete by 0.14 to 0.18 g / cm3, while the concrete strength is also reduced by 30 to 50%, which leads to very weakness and flexural strength of less than about 10 kg / cm3. As it is very low, the use as building materials is very limited.

The present invention has been proposed to solve the above problems, by using carbon fiber and steel as reinforcing material, carbon fiber and steel reinforcement lightweight foam cement composite having excellent behavior after maximum load by light weight by the general casting (Casting) method The purpose is to produce the material.

Hereinafter, the present invention will be described.

The present invention is a method for producing a lightweight foam cement composite material mixed with a water reducing agent 0.001 ~ 0.005 (reducing agent / binder, weight ratio, binder = cement + silica groove) and air emollient 0.001 ~ 0.005 (air emulsifier / binder, weight ratio) 0.5 to 4.0 vol% of the primary reinforcing agent was added to the cement matrix consisting of a mixed solution melted in 0.3 to 0.4 (mixed water / binder, weight ratio) and silica fume 0.05 to 0.3 (silica fume / binder, weight ratio). After that, the secondary reinforcing material is added to 0.1 ~ 2.0vol% of the steel by molding and curing in a conventional manner to a method for producing a cement composite material with carbon fiber and steel reinforcement lightweight.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

The cement is generally preferably portland cement, and in addition, it can be used as a special cement such as alumina cement and mixed cement such as blast furnace slag cement, pozzolan cement, and fly ash cement.

Silica fume is a highly reactive substance which can improve the dispersion and workability of the cement mixture. When the addition amount of silica fume is less than 0.05 by weight to the binder, it does not provide sufficient filling effect between the fibers, so that the dispersion effect of carbon fiber (14.5㎛), which is a reinforcing agent, cannot be expected. This is undesirable because it leads to an increase in specific gravity.

As a sensitizer, condensed naphthalene sulfonate sodium salt system is effective, but any sensitizer which can give a sensitizing effect can be used. If the content of the water reducing agent is 0.001 or less in weight ratio with respect to the binder, the water reducing effect may not be obtained, and if the content of the water reducing agent is 0.005 or more, the effect of addition may not be expected.

The air entrainer is a small amount of foam stabilizer, Triethanol Amine (TEA) Lauryl Sulfate, added to Sodutm Lauretl Sulfate, and any surface active agent that can withstand high temperature and high pH atmosphere can be used. When the content of the air entrainer is 0.001 or less by weight relative to the binder, the air entraining effect is not obtained, and when the content of the air entraining agent is more than 0.005, the additive effect cannot be expected.

When the mixed water is less than 0.3 by weight to the binder, the air entraining effect cannot be obtained efficiently, and when 0.4 or more, air entraining effect is not obtained, and the strength decreases due to the decrease of specific surface energy due to the increase in the number of adsorption water. Therefore, it is not preferable.

The carbon fiber used as the primary reinforcing material uses short fibers with short fiber length, and if the added amount is less than 0.5% by volume ratio, the reinforcing effect cannot be expected, and in the case of more than 4%, it is difficult to uniformly mix and lack of matrix. It is not preferable because it not only lowers the moldability and causes a decrease in strength.

The stresses used as secondary reinforcements can be used as long as ordinary carbon steel. If the amount of steel added is less than 0.1 vol%, the reinforcing effect is not expected, and if it is more than 2 vol%, it is not preferable because entanglement of the steel occurs during mixing. In addition, representative examples of the steel may include a steel mesh and steel fiber.

Hereinafter, the present invention will be described in more detail with reference to Examples.

Example

Comparative Examples 1 to 4

As shown in Table 1 below, silica fume was added to cement in a weight ratio of binder to 0.1 and carbon fibers in a weight ratio of binder to 0.025, followed by mixing to prepare a dry mixture (dryer) as a water reducing agent 0.005 (resin / binder, weight ratio). And 0 to 0.005 of air entrainer (air entrainer / binder, weight ratio) in 0.4 (mixed water / binder, weight ratio) of mixed water, followed by kneading the mixed solution with dry mix to entrain air to 40 × 40. A molded product of 160 × 160 mm was obtained and cured for 24 hours, followed by demolding. The cured product (carbon fiber-reinforced lightweight foam cement composite) was completed by maintaining in an autoclave for 3 hours at 180 ° C. to 10 kgf / cm 3. Prepared.

Specific gravity, flexural strength and compressive strength were measured for the cured cured product as described above, and the measurement results are shown in FIG. 1 as a value according to a change in air entrainer / binder (weight ratio).

As shown in FIG. 1, as the amount of air entraining agent is increased, the specific air decreases as the entrained air increases, and thus the strength decreases, and the carbon fiber in the cured product, although the added carbon fiber and weight are constant. It can be seen that the volume content of is decreased.

Comparative Examples 5-8

As shown in Table 2 below, silica fume was added to cement in a weight ratio of 0 to 0.3 and carbon fibers in a weight ratio of binder to 0.025, and a dry mixture was prepared to prepare a dry mix, a water reducing agent 0.005 (a reducing agent / binder, a weight ratio) and After dissolving 0.003 of air entrainer (air entrainer / binder, weight ratio) in 0.4 of mixed water (mixed water / binder, weight ratio), the mixed solution was kneaded with dry mix to obtain 40 × 40 in the same manner as in Comparative Example. A molded article of 160 mm was prepared and then cured in an autoclave to form a cured product (carbon fiber reinforced lightweight foam cement composite).

Specific gravity, specific compressive strength, and specific flexural strength of the cured cured product as described above were measured, and the results of the measurement are shown in FIG.

As shown in FIG. 2, it can be seen that the continuous addition of silica fume causes an increase in specific gravity, while also increasing specific strength (strength / specific gravity).

Comparative Examples 9-13

As shown in Table 3 below, silica fume was added to the cement in a weight ratio of binder to 0.1 and carbon fibers in a weight ratio of binder to 0 to 0.109, followed by mixing to prepare a dry mix, a water reducing agent of 0.005 (a reducing agent / binder, a weight ratio) and After dissolving 0.003 of air entrainer (air entrainer / binder, weight ratio) in 0.4 of mixed water (mixed water / binder, weight ratio), the mixed solution was kneaded with dry mix to obtain 40 × 40 in the same manner as in Comparative Example. After molding a × 140 mm molded body and cured in an autoclave to produce a cured body (carbon fiber reinforced lightweight foam cement composite).

Specific gravity, specific compressive strength and specific flexural strength were measured for the cured cured product as described above, and the measurement results are shown in FIG.

As shown in FIG. 3, as the carbon fiber content increases, the specific gravity decreases as more air is entrained, and the specific compressive strength decreases as the specific flexural strength increases.

Inventive Examples 1 to 4

As shown in Table 4 below, silica fume was added to the cement in a weight ratio of binder to 0.1 and carbon fiber in a weight ratio of 0 to 0.027 in a weight ratio of the binder, and mixed to prepare a dry mix, a water reducing agent 0.005 (a reducing agent / binder, a weight ratio) and After dissolving 0.003 of air entrainer (air entrainer / binder, weight ratio) in 0.4 of mixed water (mixed water / binder, weight ratio), the mixed solution is kneaded with a dry mix, followed by air mixing. Fill the mold together, and in the case of steel fibers, knead again after addition of steel fibers, pour them into a block mold of 230 × 114 × 65 mm, demoulding in the same manner as the comparative example, curing in an autoclave, and curing the hardened body (carbon fiber and steel reinforcement). Lightweight foam cement composite) was prepared.

Density, flexural strength, compressive strength and post peak behavior were investigated for the cured cured product as described above, and the results are shown in Table 5 below. In addition, the flexural load-deflection relationship was observed for the cured product, and the results are shown in FIGS. 4 and 5.

a: energy up to yield point b: energy up to breakdown point

The flexural strength was improved with the addition of steel as shown in Table 5, and the post-peak behavior, which represents the ratio of the amount of energy grooves before and after the maximum load, was increased by about three times. In addition, as shown in Figures 4 and 5, it can be seen that the behavior after the maximum load is improved by the addition of steel.

Claims (3)

In the method for producing a lightweight foam cement composite material, a water reducing agent of 0.001 ~ 0.005 (reducing agent / binder, weight ratio, binder = cement + silica fume) and air emollient 0.001 ~ 0.005 (air emulsifier / binder, weight ratio) 0.3 ~ 0.5 to 4.0 vol% of the primary reinforcing agent was added to the cement matrix consisting of a mixed solution melted at 0.4 (mixed water / binder, weight ratio) and silica grooves 0.05 to 0.3 (silica fume / binder, weight ratio), followed by sufficient mixing. , The method of manufacturing a carbon fiber and steel reinforced lightweight foam cement composite material, characterized in that the molding and curing in the usual manner by adding 0.1 ~ 2.0vol% of the steel is a secondary reinforcing material. The method of producing a carbon fiber and steel reinforced lightweight foam cement composite according to claim 1, wherein the water reducing agent is a condensed naphthalene sulfonic acid sodium salt system. The method for producing a carbon fiber and steel reinforced lightweight foam cement composite according to claim 1 or 2, wherein the secondary steel is a steel mesh or a rigid oil.