KR102121560B1 - Calcium sulfur aluminate high early strength material, and composition for low weight repair mortar comprising thereof - Google Patents

Abstract

The present invention is a calcium aluminate cement comprising 50 to 60% by weight of calcium aluminate cement, 30 to 40% by weight of calcium fly ash, and 5 to 10% by weight of a hydration accelerator, and comprising a waste artificial stone aggregate It relates to a low weight repair mortar composition characterized by.
According to the present invention, it is possible to manufacture a high-strength calcium sulfaluminate that can replace the existing natural gypsum by recycling the high-calcium fly ash discarded as a conventional industrial by-product. In addition, a low weight repair mortar composition capable of suppressing the slip phenomenon of the wall surface due to high weight is produced by replacing natural silica sand by pulverizing a lightweight aggregate of low density artificial stone with a specific average particle size to the high strength calcium sulfaluminate. It can be, such a low weight repair mortar composition of the present invention has the effect of preventing secondary defects in the repair portion of the concrete structure and having a low absorption and high durability.

Description

Calcium sulfaluminate crude steel and low weight repair mortar composition comprising the same {CALCIUM SULFUR ALUMINATE HIGH EARLY STRENGTH MATERIAL, AND COMPOSITION FOR LOW WEIGHT REPAIR MORTAR COMPRISING THEREOF}

The present invention relates to a calcium sulfaluminate crude steel material and a low weight repair mortar composition comprising the same, and in detail, to prepare a calcium sulfaluminate crude steel material using a high calcium fly ash, and to reduce the weight of the repair mortar, the waste artificial stone is lightweight It relates to a low weight repair mortar composition comprising an aggregate.

The concrete structure is exposed to erosion due to the erosion of the surface due to the neutralization, salt damage, and freezing and thawing due to external deterioration factors, erosion due to cracks in the coated concrete area, and secondary cracking due to corrosion of the rebar and corrosion expansion. The endurance due to this will end.

Most modern buildings are composed of concrete structures, and it is highly likely that concrete structures deteriorate due to concrete deterioration in old structures over 30 years old. In order to continuously increase the durability of the aged structure, it is possible to improve the durability of the structure by removing the deterioration of the surface and constructing a repair mortar on the top.

In particular, repair work on high roads, high-rise structures, and structures that are greatly affected by gravity, such as ceilings, has a problem that the heavy-weight repair mortar is peeled off before hardening due to slip phenomenon caused by gravity, so repair mortar using lightweight aggregate I am using it.

However, the light weight aggregate, which is a main material for manufacturing a lightweight repair mortar, has a high absorption rate of about 20%, and a large number of voids inside, resulting in low physical properties.

General plastics with relatively high physical properties can be used as aggregates, but only plastics that require adequate brittleness to derive proper particle size through impact in the crushing process to obtain proper particle size can be used. In the case, the price of mortar is more than about 2,000 won per kg, and there is a problem in that the price of mortar increases rapidly.

On the other hand, as another way to suppress the slip phenomenon, there is a method of accelerating curing by shortening the setting time after an appropriate working time after the mortar construction. However, in order to promote curing, it is essential to use expensive materials such as calcium sulfaluminate (hereinafter referred to as “CSA”) or lithium carbonate.

There are two types of CSA manufacturing methods: calcination of the main components of C3A, and alumina cement mixing with gypsum and quicklime.

Korean Patent Application No. 2014-0158866

Accordingly, an object of the present invention is to provide a high strength calcium sulfaluminate crude steel material capable of improving physical performance of a lightweight repair mortar using lightweight aggregate.

In addition, another object of the present invention is to provide a low weight repair mortar composition that can replace the existing lightweight aggregate using the high strength calcium sulfaluminate crude steel.

The calcium sulfoaluminate crude steel material prepared using the high calcium fly ash according to the present invention and the low weight repair mortar composition using fine aggregates by pulverizing the waste artificial stone are provided with the following solutions.

The calcium sulfoaluminate crude steel according to the present invention may include 50-60% by weight of calcium aluminate cement, 30-40% by weight of calcium fly ash, and 5-10% by weight of hydration accelerator.

In addition, the alumina cement is Al ₂ O ₃ It is preferable that the content is 50 to 70% and the CaO content is 15 to 30%.

In addition, the calcium sulfoaluminate crude steel material may further include at least one organic acid retarder selected from tartaric acid, citric acid, and maleic acid in an amount of 0.001 to 0.090 wt% based on 100 wt% of the total crude steel.

In addition, the hydration accelerator is preferably a calcium salt of a carboxylic acid-based calcium formate.

The low weight repair mortar composition according to the present invention may include the calcium sulfoaluminate crude steel and the waste artificial stone aggregate.

In addition, the low weight repair mortar composition is 100 parts by weight of cement-based powder containing 5 to 10 parts by weight of CSA crude steel, 40 to 50 parts by weight of light weight aggregate of artificial stone with an average particle size of 0.3 to 0.6 mm, and an average particle size of 0.1 to 0.35 It may include 50 to 60 parts by weight of natural silica sand in the range of mm.

According to the present invention, it is possible to manufacture a high strength calcium sulfaluminate crude steel material that can replace the existing natural gypsum by recycling the high calcium fly ash that is discarded as a by-product of the prior art.

In addition, a low weight repair mortar composition capable of suppressing the slip phenomenon of the wall surface due to high weight is produced by replacing the natural silica sand by crushing the lightweight aggregate with low specific gravity having a specific average particle size in the high strength calcium sulfaluminate in the form of silica sand. The low weight repair mortar composition of the present invention can prevent secondary defects in the repair part of the concrete structure and have high durability while having low water absorption.

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

The terminology used herein is used to describe a specific embodiment and is not intended to limit the present invention.

As used herein, singular forms may include plural forms unless the context clearly indicates otherwise. Also, as used herein, “comprise” and/or “comprising” specifies the shapes, numbers, steps, actions, elements, elements and/or the presence of these groups. And does not exclude the presence or addition of one or more other shapes, numbers, actions, elements, elements and/or groups.

The present invention relates to a calcium sulfoaluminate (CSA) crude steel, which is a major performance improving agent for producing a lightweight repair mortar, and a low weight repair mortar composition comprising the same.

The CSA crude steel according to the present invention is characterized by using a high calcium fly ash that replaces the existing natural anhydrous gypsum as a powder for controlling the reactivity of alumina cement and realizing strength, and is characterized by realizing appropriate expansion and strength.

In the CSA crude steel according to the present invention, calcium aluminate cement has a high hydration rate and thus high strength can be obtained at an early stage, and is known as a material having high chemical resistance. We tried to control this by incorporating high calcium fly ash, a natural anhydrous gypsum substitute for proper expansion, and using organic acid retarders and hydration accelerators to derive an appropriate working time according to competitive adsorption reactions.

The CSA crude steel of the present invention is preferably composed of 50 to 60% by weight of calcium aluminate cement, 30 to 40% by weight of calcium fly ash, and 5 to 10% by weight of hydration accelerator.

The calcium aluminate cement contained in the CSA crude steel is Al ₂ O ₃ The content is 50% or more, preferably 50 to 70%, and the CaO content is 30% or less, preferably 15 to 30%. The Al ₂ O ₃ If the content is less than 50%, there is a problem of low condensation delay and initial strength, and if it exceeds 70%, the initial condensation is rapidly accelerated, resulting in a decrease in long-term strength and a rapid rise in price, which is economical. Can't.

In addition, when the CaO content is less than 15%, there is a problem that condensation is delayed due to a decrease in the supply amount of CaO required for hydration promotion, and when it exceeds 30%, cracks on the surface may occur due to heat generation due to excessive CaO. It is not desirable.

Calcium aluminate cement having these characteristics is included in 50 to 60% by weight of the total CSA crude steel composition, if the content is less than 50%, there is a problem that the initial strength is lowered, and if it exceeds 60%, the long-term strength is reduced It is not desirable.

The high calcium fly ash contained in the CSA crude steel of the present invention is a material that is discarded as an industrial by-product, but in the present invention, it was used as a substitute for natural anhydrous gypsum for appropriate expansion.

The high calcium fly ash is preferably included in 30 to 40% by weight of the total CSA crude steel composition, there is a problem that the long-term strength is lowered when its content is less than 30% by weight, and when it exceeds 40% by weight, due to sulfate There is a problem that the setting time is delayed and the initial strength is lowered due to the exothermic suppression and delay of hydration by reaction with alumina.

The hydration accelerator included in the CSA crude steel composition of the present invention is preferably a calcium salt of a carboxylic acid-based calcium formate, and its content may be included in 5 to 10% by weight of the total CSA crude steel composition. When the content of the hydration accelerator is less than 5% by weight, there is a problem that the setting time is delayed, and when it exceeds 10% by weight, the structure of the hydrate due to the rapid formation of the internal hydrate by the hydration accelerator may not be densely formed, so the initial Strength and long-term strength cannot be improved properly.

In addition, the CSA crude steel composition of the present invention includes an organic acid retardant, which is a saccharide-based retarder including tartaric acid, citric acid, maleic acid, etc., in an amount of 0.001 to 0.090% by weight of 100% by weight of the total CSA crude steel composition. It is desirable in terms of securing the castle.

In addition, the present invention provides a low weight repair mortar composition comprising the above-prepared CSA crude steel and lightweight artificial waste stone aggregate.

The composition according to the present invention, the CSA crude steel with respect to 100 parts by weight of cement-based powder containing 5 to 10 parts by weight of the average particle size of 0.3 to 0.6mm range of artificial stone aggregate 40 to 50 parts by weight, and the average particle size of 0.1 to 0.35mm range It may be included as 50 to 60 parts by weight of natural silica.

The cement-based powder according to the present invention is substituted with about 10% by weight or less of the CSA crude steel, for example, 90 parts by weight of ordinary cement including 60 parts by weight of 1 type ordinary Portland cement and 30 parts by weight of 3 types of blast furnace slag. The prepared CSA crude steel may be a composition including 10 parts by weight, but is not limited thereto.

The prepared CSA crude steel is less than 10 parts by weight, preferably 5 to 10 parts by weight of 100 parts by weight of the total cement-based powder.

In addition, the mortar composition according to the present invention may include 40 to 50 parts by weight based on 100 parts by weight of the cement-based aggregate of the waste artificial stone aggregate having an average particle size of 0.3 to 0.6 mm together with the CSA crude steel.

When using aggregates outside the average particle size range as the artificial stone aggregate, flow is reduced due to small particle size, and compression strength is deteriorated, which is not preferable.

In addition, when the content of the waste artificial stone aggregate in the average particle size range of 0.3 to 0.6 mm is less than 40 parts by weight based on 100 parts by weight of the cement-based powder, the filling capacity of the waste artificial stone aggregate increases, so that the decrease in unit volume weight is not large, and the content thereof When it is mixed in excess of 50 parts by weight, the bonding strength between the waste artificial stone aggregate and the cement paste is low, which is not preferable because there is a problem that the strength is lowered.

The artificial stone aggregate having an average particle size of 0.3 to 0.6 mm in accordance with the present invention replaces a part of the conventional natural silica sand. In the present invention, natural silica sand having an average particle size of 0.1 to 0.35 mm is used for 100 parts by weight of cement-based powder. It may contain 50 to 60 parts by weight.

Hereinafter, a preferred embodiment of the present invention will be described in detail. The following examples are only intended to illustrate the invention and should not be construed as limiting the scope of the invention by these examples. In addition, in the following Examples, although specific compounds have been exemplified, it is apparent to those skilled in the art that even when these equivalents are used, the similar effects can be exerted.

Example 1-2 and Comparative example 1~6: CSA Crude steel Produce

CSA crude steel according to each Example and Comparative Example was prepared with the composition shown in Table 1 below. As for water cement ratio and aggregate, the standard yarn used was based on what was stated to use 48.5 parts by weight of water and 100 parts by weight of cementitious material as specified in KS L 5110, and 245 parts by weight as standard yarn.

Unit: weight% Example Comparative example One 2 One 2 3 4 5 6 Calcium aluminate cement ⁽¹⁾ 50 60 60 40 70 65 60 60 Anhydrous plaster - - 30 - - - - - High calcium fly ash 40 30 - 60 30 30 37 25 Hydration accelerator ⁽²⁾ 10 10 10 10 10 5 3 15 Organic Acid Retarders ⁽³⁾ 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 Water cement ratio 48.5% Standard yarn 245 (1) Al ₂ O ₃ Calcium aluminate cement with 50% CaO and 30% CaO.
(2) Hydration accelerator is a calcium formate 98% reagent
(3) Organic acid retardant is tartaric acid.

Experimental Example One : CSA Measurement of physical properties of crude steel

The physical properties of each CSA crude steel material prepared with the composition of Table 1 were measured, and the results are shown in Table 2 below.

Item Example Comparative example One 2 One 2 3 4 5 6 Setting time (H:Min) First 4:30 4:15 4:00 5:00 3:30 3:50 5:00 3:00 closing 6:40 6:30 6:50 7:00 5:00 5:15 7:30 4:30 Compressive strength (N/㎟): 3 days 20.4 23.1 19.5 17.4 26.4 25.4 15.4 21.4 Compressive strength (N/㎟): 7 days 31.6 30.5 29.8 30.5 28.1 29.8 26.3 23.5 Compressive strength (N/㎟): 28 days 36.8 38.4 36.7 36.5 31.3 37.3 34.5 28.4

In the case of Comparative Example 2 in which the content of calcium aluminate cement of the composition was less than 50% by weight, the initial strength (3 days) was lowered, and in Comparative Examples 3 and 4 exceeding 60% by weight, long-term strength (7 days) , 28 days).

In addition, in the case of Comparative Example 6 in which the content of the high calcium fly ash was less than 30% by weight, long-term strength (28 days) was lowered, and in the case of Comparative Example 2 in excess of 40% by weight, due to the reaction with alumina by sulfate. There is a problem that the setting time is delayed and the initial strength (3 days) decreases due to heat suppression and delay in hydration.

In addition, in the case of Comparative Example 5 in which the content of the hydration accelerator was less than 5% by weight, the setting time was delayed, and when it exceeds 10% by weight, the structure of the hydrate due to the rapid generation of internal hydrate by the hydration accelerator is dense. Since it is not produced, the enhancement of initial strength and long-term strength cannot be achieved properly.

Example 3-4 and Comparative example 7~10: Low weight Preparation of repair mortar composition

The prepared CSA crude steel (Examples 1 to 2, and Comparative Examples 1 to 4) and a low weight repair mortar comprising a lightweight artificial stone aggregate according to Table 3 were prepared.

The reference powder used in each of Examples and Comparative Examples in Table 3 included 90 parts by weight of common cement and 60 parts by weight of CSA, including 60 parts by weight of 1 type ordinary Portland cement and 30 parts by weight of 3 types of blast furnace slag. At this time, the water cement ratio may be composed of 35%.

Experimental Example 2 : Low weight Measurement of physical properties of water-retained mortar composition

The physical properties of each of the prepared low-weight water-retaining mortar compositions were measured, and the results are shown in Table 3 below.

standard
Powder Waste artificial stone aggregate natural
Silica sand ⁽³⁾
(Company 7) Water cement ratio (%) Unit volume weight
(kg/㎥) Flow
(mm) Compressive strength (N/mm ² ) Size 7 ⁽¹⁾ No. 6 ⁽²⁾ 3 days 7 days 28 days Example 3

100 - 50 50

35% 2,010 180 18.4 22.3 42.8 4 - 40 50 2,120 175 17.7 21.8 41.9
Comparative example 7 - 30 70 2,350 170 16.4 21.3 38.6 8 - 60 40 1,960 185 14.1 17.5 30.2 9 50 - 50 2,050 150 13.4 16.8 24.8 10 - - 100 2,450 170 16.8 20.4 38.6 (1) Waste artificial stone aggregate No. 7: Average particle size range of 0.1 ~ 0.35mm
(2) Waste artificial stone aggregate No. 6: Average particle size range of 0.3 ~ 0.6mm
(3) Natural silica No. 7: Average particle size 0.1 ~ 0.35mm range

Referring to the results of Table 3, in the case of Comparative Example 9 using the No. 7 yarn as a waste artificial stone aggregate, the flow decreases due to the small particle size, and there is a problem that the compressive strength decreases.

In addition, even if a waste artificial stone aggregate of No. 6 in the average particle size range of 0.3 to 0.6 mm is used as in the present invention, when its content is less than 40 parts by weight (Comparative Example 7), the unit volume weight increases the filling performance of the waste artificial stone aggregate. The decrease in unit volume weight is not great, and when the content is mixed in excess of 50 parts by weight (Comparative Example 8), there is a problem in that the strength between the waste artificial stone aggregate and the cement paste is low and the strength is lowered.

Therefore, when the optimum content of CSA crude steel produced using a high calcium fly ash and a waste artificial stone aggregate having a specific average particle size as in the present invention is possible, it is possible to manufacture a lightweight repair mortar, and the prepared repair mortar has physical performance It can be seen that it has the effect of recycling high-calcium fly ash, which is discarded as an industrial by-product, without deterioration.

Claims (6)

In the low weight repair mortar composition using a lightweight aggregate,
Al ₂ O ₃ content is 50~70%, CaO content is 15~30%, calcium aluminate cement 50~60% by weight, calcium fly ash 30~40% by weight, and hydration accelerator 5~10% by weight, ,
Cement standard that contains 5 to 10 parts by weight of high strength calcium sulfoaluminate crude steel having a compressive strength (N/㎟) of 3 days or more, a compressive strength of 30 or more at 7 days, and a compressive strength of 36 or more at 28 days With respect to 100 parts by weight of powder,
The lightweight aggregate replaces 40-50 parts by weight of the natural silica sand with a lightweight aggregate that is crushed to an average particle size of 0.3 to 0.6mm, and the remaining 50-60 parts by weight of natural silica with an average particle size of 0.1 to 0.35mm. Low weight water mortar composition, characterized in that made using. delete According to claim 1,
The hydration accelerator is a low weight water-retaining mortar composition, which is a calcium salt of a carboxylic acid based with calcium formate. According to claim 1,
The calcium sulfoaluminate crude steel material is a low weight water-retaining mortar composition containing at least one organic acid retarder selected from tartaric acid, citric acid, and maleic acid in an amount of 0.001 to 0.09% by weight relative to 100% by weight of the total crude steel. delete delete