KR102152589B1 - A method for internal curing of concrete using plants powder - Google Patents

Abstract

The present invention relates to a concrete internal curing method using plant powder and, more specifically, to a concrete internal curing method using plant powder, which uses the plant powder separated from phloem of the plant stem to reduce the curing time and improve the curing efficiency, is eco-friendly by using the plant powder, a natural substance, and mixes concrete with improved strength and durability.

Description

Concrete internal curing method using plant powder {A method for internal curing of concrete using plants powder}

The present invention relates to a concrete internal curing method using plant powder, and more specifically, by using the plant powder separated from the bast tissue of the plant stem, it is possible to shorten the curing time and improve the curing efficiency. It is environmentally friendly because it is used, and it relates to a concrete internal curing method using plant powder capable of mixing concrete with improved strength and durability.

Concrete, which uses inorganic materials as its main constituents, has both strength and durability and has been widely used in construction works since long ago. In particular, in the case of alumina cement-based crude steel concrete, it is true that the curing time for securing the target strength has been shortened compared to conventional concrete (Ordinary Portland Cement) by promoting the hydration reaction inside the concrete matrix.

However, in the case of extreme environmental conditions below -20 ℃, it is true that it is difficult to secure curing and early strength only with the self-hydration properties of concrete, and research cases on curing concrete or concrete structures under extreme conditions were insufficient. In order to overcome this, the internal curing method, which is a method that promotes the chemical action inside the concrete, appeared.

As shown in FIG. 1, internal curing refers to a method in which water is supplied from the concrete to perform curing, unlike external curing in which water is supplied from the outside. This internal curing is known to have excellent durability because the concrete interior is formed densely compared to the external curing.

As a representative internal curing method, studies related to internal curing of concrete using high absorbent resin (SAP), a white powder type synthetic resin prepared by mixing acrylic acid and caustic soda, are being conducted. However, when the super absorbent polymer is applied to the internal curing of concrete, the supply cost is too high to be applied to mass industries to produce it, and most super absorbent polymers are materials made of organic compounds or derivatives thereof and are not environmentally friendly. Contamination problems may occur.

Accordingly, in order to compensate for the above-described problems, the present inventors recognized that it is urgent to develop a curing method that is environmentally friendly and exhibits improved curing efficiency, and thus completed the present invention.

Korean Patent Publication No. 10-1511320

Cement and Concrete Composites, 34(9), 1001-1008.

An object of the present invention is to shorten the curing time and improve the curing efficiency by using the plant powder separated from the bast tissue of the plant stem, and because of the use of natural plant powder, it is eco-friendly, concrete with improved compressive strength and durability It is to provide a concrete internal curing method using plant powder that can be mixed.

In order to achieve the above object, the present invention provides a concrete internal curing method using environmentally friendly plant powder.

Hereinafter, the present specification will be described in more detail.

The present invention provides a concrete internal curing method using plant powder comprising the following steps.

(S1) saturating the plant powder with water for 4 to 8 hours;

(S2) preparing a mixture by adding the plant powder to a concrete blend and a polycarboxylic acid-based (PC-based) high-performance water reducing agent; And

(S3) Injecting and pouring the mixture into a concrete mold, and internal curing is performed due to the plant powder to produce concrete.

In the present invention, the plant powder is at least one selected from the group consisting of kenaf, hemp, jute, abaca, or a mixed powder thereof, and the stem bast of the plant It is characterized in that it is separated from the tissue and powdered to a particle size of 50 to 250 μm.

In the present invention, the plant powder comprises 0.1% to 3.0% by weight relative to the binder, and the polycarboxylic acid-based (PC-based) high-performance water reducing agent comprises 0.001% to 5.0% by weight relative to the binder To do.

In the present invention, the concrete blend is a binder; water; And sand in a weight ratio of 1:0.3:2.

In the present invention, the binder is one Portland cement; And at least one admixture selected from the group consisting of fly ash, blast furnace slag powder, silica fume, or mixtures thereof.

In the present invention, the binder is characterized in that the first type Portland cement: admixture is mixed in a weight ratio of 1 to 0.4: 0 to 0.6.

The concrete internal curing method using the plant powder of the present invention is eco-friendly and can shorten the curing time because it uses plant powder having excellent moisture content and dispersibility to supply moisture inside the concrete, thereby improving curing efficiency. I can make it.

In addition, since the concrete internal curing method of the present invention uses plant powder, it generally forms a concrete interior with a low water binding material ratio (w/b) to show improved compressive strength and durability, and thus, the concrete is formed densely. It has excellent heat insulation and sound insulation properties.

1 is a conceptual diagram briefly explaining the principles of external curing and internal curing.
Figure 2 is a graph confirming the compressive strength of the internally cured concrete according to Example 1.

Hereinafter, the present invention will be described in detail. Prior to this, terms or words used in the specification and claims should not be construed as being limited to their usual or dictionary meanings, and the inventors appropriately explain the concept of terms in order to explain their own invention in the best way. Based on the principle that it can be defined, it should be interpreted as a meaning and concept consistent with the technical idea of the present invention.

The present invention provides a concrete internal curing method capable of showing improved compressive strength and durability by using eco-friendly plant powder.

More specifically, the present invention provides a concrete internal curing method using plant powder comprising the following steps.

(S1) saturating the plant powder with water for 4 to 8 hours;

(S2) preparing a mixture by adding the plant powder to a concrete blend and a polycarboxylic acid-based (PC-based) high-performance water reducing agent; And

(S3) Injecting and pouring the mixture into a concrete mold, and internal curing is performed due to the plant powder to produce concrete.

In the present invention, the step (S1) is a step of saturating the plant powder with water for 4 to 8 hours. More specifically, the step (S1) is a step for supplying moisture to the inside of the concrete when curing the inside of the concrete performed in the step (S2) or (S3) to be described later.

The plant powder may be one or more selected from the group consisting of sheep horse (kenaf), hemp (hemp), jute, manila hemp (abaca), or a mixed powder thereof.

The Yangma is a perennial plant of the Mallow family, a dicotyledonous plant, and is native to Africa and India. The stem stands straight, is 3~5m high, has fine hairs, and has hook-like projections between nodes. Leaves are alternate, deeply divided into palm shape, and have long petioles. In general, the sheep horse is made into fibers due to its tougher properties than jute and is used for hemp, fishing nets, ropes, and papermaking raw materials.

The hemp is an annual herbaceous plant belonging to the Hemp family, and its roots extend up to 30-40 cm underground, but have the property of being well pulled out because the outer roots are not developed. The height reaches 3m in temperate regions and up to 6m in tropical regions. When used as a fiber, the hemp is used to make cloth, rope, string, and thread.

The jute is a perennial herb of the dicotyledonous plant, Mallow, Panaaceae, and has a high surface roughness and is known to have remarkably excellent structural reinforcement compared to conventional hydrophobic artificial fiber reinforcements.

The Manila Ginseng is a perennial plant of the Ginger tree Pachodae, a monocotyledonous plant, and is originated from the Philippines, which has a high temperature. The manila ginseng adapted to the same climate as the Philippines has strong water resistance and excellent tensile strength.

The plant powder may be purchased and used in the market, or the plant may be purchased and manufactured using a known method at a constant temperature and humidity. The plant powder used in the present invention was prepared and used by purchasing the plant and pulverizing it at a constant temperature and humidity using a known method.

The plant powder is separated from the stem bast tissue of the sheep horse, hemp, jute or manila ginseng, and more specifically, may be separated from and powdered from the tissue remaining outside the stem forming layer in the sheep horse, hemp, jute or manila ginseng. have.

In the present invention, the powdering of the plant may be prepared by putting the plant into a pulverizer and pulverizing the plant to a particle size of 50 to 250 μm for 1 to 5 minutes at a speed of 20,000 to 25,000 rpm.

The plant powder may have a particle size of 50 to 250 μm. More specifically, when the plant powder has a particle size of less than 50 μm, there may be insufficient pores to maintain water, and this may result in a problem that may reduce the internal curing efficiency of concrete. . In addition, when the plant powder has a particle size exceeding 250 μm, the size of the pore existing inside the plant powder is excessive, so that mechanical properties such as compressive strength of concrete may be weakened. If the space itself exists as macro pores, even if the unhydrated cement around the plant powder undergoes a hydration reaction, it may be difficult to fill it. Therefore, the plant powder may preferably have a particle size of 50 to 250 μm, more preferably 100 to 200 μm.

The plant is generally processed and used in the form of short fibers, but the plant short fibers require very high processing (processing) cost and time, and are therefore unsuitable for use in the present invention for application to mass industries. On the other hand, the plant powder is easy to process compared to the staple fibers of plants, so it is easy to be applied to mass industries, and the particle size is uniform to shorten the curing time and at the same time exhibit excellent durability. The preferred form of plant processing applied may be plant powder rather than short plant fibers.

In the present invention, the step (S2) may be a step of preparing a mixture by adding plant powder saturated with water by the step (S1) to a concrete blend and a polycarboxylic acid-based (PC-based) high-performance water reducing agent; .

The term used in the present invention, the "polycarboxylic acid-based (PC-based) high-performance water-reducing agent" is a water-reducing agent superior in dispersion effect than a general water-reducing agent having polycarboxylic acid as its main composition, and its main purpose is to improve the workability of concrete. It is a mixture agent. When the polycarboxylic acid-based (PC-based) high-performance water reducing agent is used for curing concrete, durability of concrete is improved and strength can be improved.

The plant powder may contain 0.1% to 3.0% by weight of the binder. More specifically, when the plant powder contains less than 0.1% by weight of the binder, it is insufficient to supply water required for internal curing of the concrete, and the curing efficiency of the concrete is significantly reduced, resulting in uniform curing quality due to an increase in shrinkage. When the plant powder is included in an amount exceeding 3.0% by weight of the binder, an excessive amount of water is supplied to the inner curing of the concrete, and the concrete is not formed densely, resulting in a problem of poor durability. . Therefore, the plant powder is preferably contained in an amount of 0.1 to 3.0% by weight, more preferably 0.5 to 1.5% by weight of the binder.

The polycarboxylic acid-based (PC-based) high-performance water reducing agent may be included in an amount of 0.001% to 5.0% by weight relative to the binder. More specifically, when the polycarboxylic acid-based (PC-based) high-performance water reducing agent is included in an amount less than 0.001% by weight of the binder, it exhibits effects such as durability or strength improvement in an insignificant amount so that it cannot perform the role of the high-performance water reducing agent. If the high-performance water-reducing agent is included in an amount of 5.0% by weight compared to the binder, material segregation of unhardened concrete may occur. Therefore, the polycarboxylic acid-based (PC-based) high-performance water-reducing agent is 0.001 compared to the binder. It is preferable to include it in weight% to 5.0% by weight, more preferably 0.01 to 2.5% by weight.

In the present invention, the concrete blend is a binder; water; And to be blended with sand, more specifically, the concrete blend is a binder; water; And sand in a weight ratio of 1:0.3:2.

In particular, when the ratio of the water binder (w/b) in the concrete blend is lowered to less than 0.3, the workability is significantly deteriorated, and when it exceeds 0.35, the strength of the concrete decreases as the value increases, and the internal curing is required. There may be a problem that the concrete internal structure is absent.

In the present invention, the binder is one Portland cement; And at least one admixture selected from the group consisting of fly ash, blast furnace slag fine powder, silica fume, or mixtures thereof.

The binder may be mixed in a weight ratio of 1 to 0.4: 0 to 0.6 of the first type Portland cement: admixture. More specifically, when the admixture is included in the binder in an amount exceeding 0.6 weight ratio, the amount of cement is reduced, so that the concrete curing time may be lengthened and durability may be reduced, so that the binder is the type 1 Portland cement: admixture from 1 to It is preferable to mix in a weight ratio of 0.4: 0 to 0.6.

In the present invention, the binder is to use a mixture of the first type Portland cement and admixture in order to lower the alkalinity of the concrete mix, since plant fibers may be corroded in a high alkaline blend.

In the present invention, the step (S3) may be a step in which the mixture prepared in the step (S2) is injected and poured into a concrete mold, and internal curing is performed due to the plant powder to produce concrete.

In the present invention, the (S1) to (S3) steps may be performed at room temperature or room temperature, and the mixing or blending may be performed at a speed of 100 to 1000 rpm.

Hereinafter, examples will be described in detail to illustrate the present invention in detail. However, the embodiments according to the present invention may be modified in various forms, and the scope of the present invention should not be construed as being limited to the embodiments described below. The embodiments of the present invention are provided to more completely describe the present invention to those of ordinary skill in the art.

Example 1. Concrete cured internally using plant powder 1

Saturating the sheep horse powder with water for 6 hours, and using the sheep horse powder as a binding material, Portland cement; water; And sand in a weight ratio of 1:0.3:2 and added to a concrete blend and a polycarboxylic acid-based (PC-based) high-performance water reducing agent, and mixed at a speed of 100 rpm for 20 minutes. At this time, the sheep powder was added 1% by weight of the binder, and the polycarboxylic acid-based (PC-based) high-performance water reducing agent was added 1% by weight of the binder. In addition, the mixture was put into a concrete mold and poured. Finally, after 24 hours passed, the concrete was demolded from the concrete mold and internally cured for 28 days to prepare concrete.

Example 2. Concrete 2 internally cured using plant powder

Saturating the sheep horse powder with water for 6 hours, and combining the sheep horse powder with a binder; water; And sand in a weight ratio of 1:0.3:2 and added to a concrete blend and a polycarboxylic acid-based (PC-based) high-performance water reducing agent, and mixed at a speed of 100 rpm for 20 minutes. At this time, the binder is a mixture of 1 type Portland cement: fly ash in a 0.8: 0.2 weight ratio, and 1% by weight of the powder is added to the binder, and the polycarboxylic acid-based (PC-based) high-performance water reducing agent is 1% by weight of the binder was added. In addition, the mixture was put into a concrete mold and poured. Finally, after 24 hours passed, the concrete was demolded from the concrete mold and internally cured for 28 days to prepare concrete.

Example 3. Concrete 3 internally cured using plant powder

Saturating the sheep horse powder with water for 6 hours, and combining the sheep horse powder with a binder; water; And sand in a weight ratio of 1:0.3:2 and added to a concrete blend and a polycarboxylic acid-based (PC-based) high-performance water reducing agent, and mixed at a speed of 100 rpm for 20 minutes. At this time, the binder is a mixture of one type of Portland cement: fly ash in a weight ratio of 0.6: 0.4, and 1% by weight of the powder is added to the binder, and the polycarboxylic acid-based (PC-based) high-performance water reducing agent is 1% by weight of the binder was added. In addition, the mixture was put into a concrete mold and poured. Finally, after 24 hours passed, the concrete was demolded from the concrete mold and internally cured for 28 days to prepare concrete.

Example 4. Internally cured concrete using plant powder 4

Saturating the sheep horse powder with water for 6 hours, and combining the sheep horse powder with a binder; water; And sand in a weight ratio of 1:0.3:2 and added to a concrete blend and a polycarboxylic acid-based (PC-based) high-performance water reducing agent, and mixed at a speed of 100 rpm for 20 minutes. At this time, the binder is a mixture of one type of Portland cement: fly ash in a weight ratio of 0.4: 0.6, and 1% by weight of the powder was added to the binder, and the polycarboxylic acid-based (PC-based) high-performance water reducing agent was Add 1% by weight of the binder. In addition, the mixture was put into a concrete mold and poured. Finally, after 24 hours passed, the concrete was demolded from the concrete mold and internally cured for 28 days to prepare concrete.

Comparative Example 1. Concrete 1 that does not contain sheep powder

Binder; water; And sand in a weight ratio of 1:0.3:2 and added to a concrete blend and a polycarboxylic acid-based (PC-based) high-performance water reducing agent, and mixed at a speed of 100 rpm for 20 minutes. At this time, the binder is a type 1 Portland cement, and the polycarboxylic acid-based (PC-based) high-performance water reducing agent was added 1% by weight of the binder. In addition, the mixture was put into a concrete mold and poured. Finally, after 24 hours passed, the concrete was demolded from the concrete mold and internally cured for 28 days to prepare concrete.

Comparative Example 2. Concrete 2 that does not contain sheep powder

Binder; water; And sand in a weight ratio of 1:0.3:2 and added to a concrete blend and a polycarboxylic acid-based (PC-based) high-performance water reducing agent, and mixed at a speed of 100 rpm for 20 minutes. At this time, the binder is a mixture of 1 type Portland cement: fly ash in a weight ratio of 0.4: 0.6, and the polycarboxylic acid-based (PC-based) high-performance water reducing agent was added 1% by weight of the binder. Finally, after 24 hours passed, the concrete was demolded from the concrete mold and internally cured for 28 days to prepare concrete.

Comparative Example 3. Concrete 1 with different weight ratios of concrete blends

Saturating the sheep horse powder with water for 6 hours, and combining the sheep horse powder with a binder; water; And sand was added to the concrete blend and polycarboxylic acid-based (PC-based) high-performance water reducing agent mixed in a weight ratio of 1:1 and mixed at a speed of 100 rpm for 20 minutes. At this time, the binder was a type 1 Portland cement, and 1% by weight of the sheep powder was added to the binder, and 1% by weight of the polycarboxylic acid-based (PC-based) high-performance water reducing agent was added to the binder. Finally, after 24 hours passed, the concrete was demolded from the concrete mold and internally cured for 28 days to prepare concrete.

Comparative Example 4. Concrete 2 with different weight ratios of concrete blends

Saturating the sheep horse powder with water for 6 hours, and combining the sheep horse powder with a binder; water; And sand was added to the concrete blend and polycarboxylic acid-based (PC-based) high-performance water reducing agent mixed in a weight ratio of 1:1 and mixed at a speed of 100 rpm for 20 minutes. At this time, the binder is a mixture of one type of Portland cement: fly ash in a weight ratio of 0.4: 0.6, and 1% by weight of the powder was added to the binder, and the polycarboxylic acid-based (PC-based) high-performance water reducing agent was 1% by weight of the binder was added. Finally, after 24 hours passed, the concrete was demolded from the concrete mold and internally cured for 28 days to prepare concrete.

Experimental Example 1. Confirmation of compressive strength

In order to check the compressive strength of concrete according to the concrete internal curing method using the plant powder of the present invention, the concrete of Examples 1 and 4 and the concrete of Comparative Examples 3 and 4 were used for 60 days based on the strength of 28 days. It was confirmed, and the results are shown in FIG. 2.

Referring to Figure 2, it can be seen that the concrete produced by internal curing according to Examples 1 and 4 meets the standard of high-strength (40 MPa or more) concrete in the compressive strength standard divided into general strength, high strength, or ultra-high strength. have. On the other hand, it was confirmed that the concrete produced by Comparative Examples 3 and 4 exhibited a compressive strength of less than 15 MPa.

The above result means that the water contained in the plant powder promoted the continuous hydration reaction of the surrounding unhydrated cement. In addition, from the above results, it is suggested that the internal curing method of the present invention exhibits excellent compressive strength and durability, and thus, the concrete is formed densely and thus can have excellent heat insulation and sound insulation properties.

From the above description, it will be understood that those skilled in the art belonging to the present invention can be implemented in other specific forms without changing the technical spirit or essential features of the present invention. In this regard, the embodiments described above are illustrative in all respects, and should be understood as non-limiting.

Claims (5)

(S1) saturating the plant powder with water for 4 to 8 hours;
(S2) preparing a mixture by adding the plant powder to a concrete blend and a polycarboxylic acid-based (PC-based) high-performance water reducing agent; And
(S3) adding and pouring the mixture into a concrete mold, and performing internal curing due to the plant powder to produce concrete; including,
The concrete blend is a binder (Binder); water; And concrete internal curing method using plant powder, characterized in that the mixture of sand. The method of claim 1,
The plant powder is at least one selected from the group consisting of sheep horse (kenaf), hemp (hemp), jute, manila ginseng (abaca), or a mixed powder thereof,
Concrete internal curing method, characterized in that separated from the stem bast tissue of the plant and powdered to a particle size of 50 to 250 μm. The method of claim 1,
The plant powder contains 0.1% to 3.0% by weight relative to the binder,
Concrete internal curing method, characterized in that the polycarboxylic acid-based (PC-based) high-performance water reducing agent comprises 0.001% by weight to 5.0% by weight relative to the binder. The method of claim 1,
The concrete blend,
Binder; water; And sand in a weight ratio of 1:0.3:2. The method of claim 4,
The binding material,
Type 1 Portland Cement; And at least one admixture selected from the group consisting of fly ash, blast furnace slag fine powder, silica fume, or mixtures thereof, and
The first type Portland cement: admixture is mixed in a weight ratio of 1 to 0.4: 0 to 0.6. Concrete internal curing method.

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