KR20230135720A - Cement mortar composition comprising chitosan-based polymer and steel slag fine aggregate - Google Patents

Abstract

The present invention relates to a cement mortar composition with improved compressive strength, tensile strength and durability by mixing chitosan-based polymer, a biomimetic polymer, and steel slag fine aggregate, an industrial by-product.
The present invention is a mortar composition containing cement, fine aggregate, and mixing water, wherein the mixing water contains 5 to 10 wt% of a chitosan-based polymer (CBP) solution, and the fine aggregate contains steel slag. ) It provides a “cement mortar composition characterized in that it contains fine aggregate.”

Description

Cement mortar composition comprising chitosan-based polymer and steel slag fine aggregate}

The present invention relates to a cement mortar composition with improved compressive strength, tensile strength and durability by mixing chitosan-based polymer, a biomimetic polymer, and steel slag fine aggregate, an industrial by-product.

In the concrete industry, several studies have been conducted to develop alternatives to natural aggregates as well as to use industrial by-products as aggregates to prevent environmental damage and depletion of natural aggregates. Steel slag, a by-product of the steel industry, is produced in the form of aggregate and has a particle size similar to natural aggregate. Therefore, it is suitable for application to mortar and concrete compared to other industrial by-products.

Recently, in addition to blast furnace slag (BS), a representative slag aggregate, ferronickel slag (FS), which is produced as a by-product in the nickel industry, is receiving great attention as a mortar or concrete aggregate. Saha et al. found that the compressive strength of mortar using a mixture of FS and natural sand (NS) as aggregate increased when 50% FS was used (Saha, AK; Sarker, PK Compressive strength of mortar containing ferronickel slag as replacement of natural sand. Procedia Eng. 2017 , 171 , 689-694.). Liu et al. examined the durability of concrete using FS fine aggregate and found that the sulfuric acid resistance of concrete was improved when 27% FS was used (Liu, X.; Li, T.; Tian, W.; Wang, Y .; Chen, Y. Study on the durability of concrete with FNS fine aggregate. J. Hazard. Mater . 2020 , 381 , 120936.). Ngii et al. used a total mixture of FS and NS and found that 25% FS content was the optimal content for improving the compressive strength of concrete (Ngii, E.; Kadir, A.; Rachman, RM; Serah, M. Optimum combination of ferro-nickel slag (FeNi4) to the normal sand for the concrete compressive strength. IOP Conf. Ser. Earth Environ. Sci . 2021 , 622 , 012038.). However, despite these efforts, the recycling rate of FS is not high (Choi, S.; Kim, J.; Bae, S.; Oh, T. Effect of fly ash on compressive strength, drying shrinkage, and carbonation depth of mortar with ferronickel -slag powder. Appl. Sci. 2021 , 11 , 1037.).

Meanwhile, polymer materials have been widely used to improve the performance of cement mortar or concrete. Douba et al. investigated the properties of high-toughness polymer concrete and found that toughness was improved in samples using carbon nanotubes and polymer materials (Douba, A.; Emiroglu, M.; Kandil, UF; Taha, MMR Very ductile polymer concrete using carbon nanotubes. Constr. Build. Mater. 2019 , 196 , 468-477.). Niaki et al. studied the mechanical and thermal properties of epoxy polymer concrete using basalt fibers and nanolays and found that adding basalt fibers improved the mechanical properties and thermal stability of polymer concrete (Niaki, MH; Fereidoon, A.; Ahangari, MG Experimental study on the mechanical and thermal properties of basalt fiber and nanoclay reinforced polymer concrete. Compos. Struct. 2018 , 191 , 231-238.). Wang et al. added scrap tire rubber, an industrial by-product, to epoxy polymer concrete and found that the compressive and tensile strengths of concrete improved when 5% solid rubber was added (Wang, J.; Dai, Q.; Guo, S.; Si, R. Mechanical and durability performance evaluation of crumb rubber-modified epoxy polymer concrete overlays. Constr. Build. Mater. 2019 , 203 , 469-480.). In addition, Asdollah et al. reported that adding olethylene terephthalate (PET) filler (manufactured by crushing recycled PET bottles) can improve the fracture toughness of polymer concrete (Asdollah-Tabar, M.; Heidari-Rarani, M.; Aliha, MRM The effect of recycled PET bottles on the fracture toughness of polymer concrete. Compos. Commun. 2021 , 25 , 100684.). However, most previous studies using polymeric materials in mortar or concrete focused on natural aggregates, and there were no reports on cement composites using steel slag fine aggregates and biomimetic polymers. Therefore, in the present invention, the applicability of chitosan-based polymer (CBP), a biomimetic polymer, to cement mortar using steel slag as a fine aggregate was examined.

1. Registered Patent 10-1680527 “Method for manufacturing mortar mixed with agar” 2. Patent Publication No. 10-2018-0083756 “Binder for improving concrete strength and polymer cement composite composition containing the same”

1. Douba, A.; Emiroglu, M.; Kandil, U.F.; Taha, M.M.R. Very ductile polymer concrete using carbon nanotubes. Constr. Build. Mater. 2019, 196, 468-477. 2. Niaki, M.H.; Fereidoon, A.; Ahangari, M.G. Experimental study on the mechanical and thermal properties of basalt fiber and nanoclay reinforced polymer concrete. Compos. Struct. 2018, 191, 231-238. 3. Wang, J.; Dai, Q.; Guo, S.; Si, R. Mechanical and durability performance evaluation of crumb rubber-modified epoxy polymer concrete overlays. Constr. Build. Mater. 2019, 203, 469-480. 4. Asdollah-Tabar, M.; Heidari-Rarani, M.; Aliha, M.R.M. The effect of recycled PET bottles on the fracture toughness of polymer concrete. Compos. Commun. 2021, 25, 100684.

The present invention examines the applicability of chitosan-based polymer (CBP), a biomimetic polymer, to cement mortar containing steel slag as a fine aggregate, and determines conditions for improving the mechanical properties and durability of cement mortar compositions. The purpose is to provide the physical characteristics of the mortar composition developed accordingly.

The present invention is a mortar composition containing cement, fine aggregate, and mixing water, wherein the mixing water contains 5 to 10 wt% of a chitosan-based polymer (CBP) solution, and the fine aggregate contains steel slag. ) It provides a “cement mortar composition characterized in that it contains fine aggregate.”

The CBP can be applied with a degree of deacetylation of 75% to 85%, and the CBP includes chitosan, hydrocaffeic acid (HCA), and 1-ethyl-3 (3-dimethylaminopropyl). It can be synthesized through an amide coupling reaction between carbodiimide hydrochloride (1-Ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride, EDC). The CBP solution can be prepared by dissolving 450 to 550 mg of CBP per 1,000 ml of water.

The fine aggregate may be a mixture of steel slag of 50 vol% or less (excluding 0 vol%) that meets the standard particle size distribution range of fine aggregate, and the steel slag may be either blast furnace slag (BS) or ferronickel slag (FS). More than one can be applied.

The cement mortar composition provided by the present invention can be mixed with 320 to 350 kg of cement per 1 ㎥ of unit volume, 700 to 750 kg of fine aggregate per 1 ㎥ of unit volume, and mixing water according to a water-cement ratio of 45 to 50 wt%,

Accordingly, the cement mortar composition has a mortar flow of 175 to 200 mm; Age 56 days Compressive strength 45 MPa or more; Age: 28 days, splitting tensile strength: 3 MPa or more; Accelerated carbonation depth of 1.0 mm or less; and chloride ion permeation of 6000 C or less at age 28 days; The physical properties can be expressed.

According to the present invention described above,

By including a chitosan-based polymer solution in the mixing water and incorporating steel slag fine aggregate into the fine aggregate, the rigidity such as compressive strength and tensile strength of the cement mortar composition and durability such as carbonation resistance and chloride penetration resistance can be improved.

[Figure 1] is the particle size distribution curve of the fine aggregate of each sample.
[Figure 2] is a structural diagram of the CBP synthesis process.
[Figure 3] shows the results of ¹ H-NMR spectroscopy analysis of the CBP sample.
[Figure 4] shows the UV-Vis absorption peak of the CBP sample.
[Figure 5] shows the peaks of the FT-IR spectrum of the CBP sample.
[Figure 6] is a graph showing the flow value of a mortar composition containing fine steel slag aggregate and CBP.
[Figure 7] shows the change in compressive strength by age of cement mortar mixture test specimens using steel slag fine aggregate and CBP.
[Figure 8] are SEM images of the BS sample and the FS sample before and after immersion in the CBP solution.
[Figure 9] shows the splitting tensile strength of cement mortar composition test specimens at 28 days of age.
[Figure 10] shows the carbonation depth measured after accelerated carbonation of cement mortar composition test specimens for 28 days.
[Figure 11] is an SEM image of BS50 and PBS50.
[Figure 12] shows the total transmitted charge for each cement mortar composition test example at 28 days of age.

The present invention is a mortar composition containing cement, fine aggregate, and mixing water, wherein the mixing water contains 5 to 10 wt% of a chitosan-based polymer (CBP) solution, and the fine aggregate contains steel slag. ) It provides a “cement mortar composition characterized in that it contains fine aggregate.”

The CBP can be applied with a degree of deacetylation of 75% to 85%, and the CBP includes chitosan, hydrocaffeic acid (HCA), and 1-ethyl-3 (3-dimethylaminopropyl). It can be synthesized through an amide coupling reaction between carbodiimide hydrochloride (1-Ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride, EDC). The CBP solution can be prepared by dissolving 450 to 550 mg of CBP per 1,000 ml of water.

Chitin extracted from clam shells is one of the representative natural polysaccharides and is considered the optimal material for producing chitosan through the deacetylation process. In general, chitin is used for the production of chitosan because it is inexpensive and the chemical reaction involved in chitosan production is suitable for mass production. This chemical reaction involves the treatment of chitin and sodium hydroxide at temperatures above 80°C. Chitosan is thus obtained as a random conjugate with D-acetyl-D-glucosamine units linked by β-1,4 glycosidic bonds. The degree of deacetylation is determined by the mass ratio of D-glucosamine and N-acetyl-D-glucosamine units and affects the molecular weight of the polymer.

Recently, chitosan has received great attention for its bioactivity, biodegradability, biocompatibility, and wide applicability in the food, pharmaceutical, textile, and tissue engineering industries. However, chitosan is soluble only in aqueous acidic media, which limits its further applications. Therefore, to expand the application range of chitosan, phenolic acid groups such as catechol are grafted onto the backbone using various amide bond reactions to improve solubility. Phenolic acid grafting improves not only the solubility but also the physicochemical properties of chitosan. In addition, chitosan containing phenolic acid has superior biological activity (antioxidant, antibacterial, antiallergenic, and anticancer agent) compared to pure chitosan.

Accordingly, the use of chitosan to improve the properties of cement mortar has been studied. Compressive strength and carbonation resistance of cement mortar can be improved by adding an appropriate amount of chitosan-based polymer (hereinafter referred to as 'CBP'), a biomimetic polymer. Choi, S.; Bae, S.; Lee, J.; Bang, E.; Ko, H. Strength, carbonation resistance, and chloride-ion penetrability of cement mortars containing catechol-functionalized chitosan. J. Polym. Mater. 2021 , 14 , 6395.). Therefore, in the present invention, CBP was synthesized and added to cement mortar containing fine steel slag aggregate. Additionally, the compressive strength, tensile strength, accelerated carbonation depth, and chloride ion permeability of the produced cement mortar were evaluated.

1. Test materials

- Chitosan: medium molecular weight, degree of deacetylation 75% to 85%

- HCA: hydrocaffeic acid (HCA)

- EDC: 1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride

- Dialysis membrane: Spectra/Por MWCO, 12-14 kDa

- Ultrapure water: Distilled with Q-Grade 1 purification cartridge

- Normal Portland cement: Specific gravity 3.15 g/cm3, fineness 3,430 ㎠/g

- Natural fine aggregate (NS): collected in Namwon, Korea

- Steel slag fine aggregate: blast furnace slag (BS) and ferronickel slag (FS) are used (see [Table 1] for specific gravity and assembly ratio). Considering the standard particle size distribution of fine aggregate, the maximum amount of steel slag used is fixed at 50 vol%.

- Sample classification

· N100: Cement mortar with fine aggregate of NS 100 vol%

· BS50: Cement mortar composed of fine aggregate of 50 vol% NS and 50 vol% BS

· BF50: Cement mortar with fine aggregates of 50 vol% NS, 25 vol% BS, and 25 vol% FS.

· FS50: Cement mortar composed of fine aggregate of 50 vol% NS and 50 vol% FS

※ The particle size distribution curve of the fine aggregate of each sample matches the standard particle size distribution range of fine aggregate as shown in the attached [Figure 1].

2. CBP synthesis

Chitosan (500 mg) was dissolved in distilled water (DW, 50 mL) and the pH of the solution was adjusted to 5.5 by adding 1.0 M HCl. In the chitosan solution, a solution of HCA (500 mg) dissolved in ethanol/DW mixture (10 mL/10 mL) and a solution of EDC (500 mg) dissolved in ethanol/DW mixture (2.5 mL/2.5 mL) were added as droplets. It was added.

The pH of the above reaction mixture was maintained at 5.5 by adding 1.0 M HCl, and the reaction mixture was stirred at room temperature for 12 hours. The reaction mixture was dialyzed against a 0.1 M NaCl solution (NaCl 30 g/4.5 L DW), and the pH was adjusted to 5.0 by adding 1.0 M HCl for two days and then adding 4.5 L DW for 4 hours. The residue was frozen at -20°C in a refrigerator and then pasteurized.

The absorbance of the aqueous CBP solution was measured using an ultraviolet-visible (UV-Vis) spectrophotometer (GENESYS 180, Thermo Fisher, USA). To obtain proton nuclear magnetic resonance ( ¹ H-NMR) spectra (500 MHz, JEOL) of CBP samples, the aqueous CBP solution was dissolved in D ₂ O (deuterated water). Fourier transform infrared (FT-IR, Nicolet iS5, Thermo Fisher Scientific) spectra of CBP samples were recorded over a wavenumber range of 400 to 4,000 cm ^-1 at 1 cm ^-1 resolution.

2. Mortar test method

The cement mortar composition provided by the present invention can be mixed with 320 to 350 kg of cement per 1 m3 of unit volume, 700 to 750 kg of fine aggregate per 1 m3 of unit volume, and mixing water according to a water-cement ratio of 45 to 50 wt%.

[Table 2] is a formulation table of cement mortar compositions for each test example. The water-cement ratio was fixed at 50%, and a CBP solution containing 500 mg of CBP dissolved in 1,000 mL of water was added to the cement mortar composition. The amount of CBP solution added compared to the amount of water contained in the cement mortar for each test example is 0% or 10.0%.

For the compressive strength test, cubic specimens measuring 50 mm in width, length, and height were prepared, and for the splitting tensile strength test, cylindrical specimens with a diameter of 50 mm and a height of 100 mm were prepared. In addition, for the accelerated carbonation test, a square column-shaped specimen with a width, length, and height of 40 mm, 40 mm, and 160 mm was prepared, and a specimen with a diameter of 100 mm and a thickness of 50 mm was prepared for the chloride ion penetration test. Each specimen was demolded 24 hours after being placed in the mold and cured in water at 20°C.

The fluidity and compressive strength of the cement mortar composition were measured according to the KS L 5105 standard, and the tensile strength was measured according to the KS F 2423 standard. In the accelerated carbonation test, the depth of carbonation was measured using a phenolphthalein solution after carbonation in an accelerated carbonation chamber according to the KS F 2584 standard. Additionally, the chloride ion penetration test was performed according to the ASTM C1202 standard. Scanning electron microscopy (SEM) images of the cement mortar composition were taken using an AIS1800C scanning electron microscope (SERON Technologies, Korea).

4. Analysis of test results

(1) CBP characteristics

CBP was synthesized through an amide bond reaction between chitosan, EDC, and HCA (see [Figure 2]). After synthesis, a white sponge-shaped solid was obtained.

The structure of the BP sample was analyzed by ¹ H NMR, UV-Vis, and FT-IR spectroscopy. The catechol group of the chitosan skeleton played an important role in increasing the solubility of CBP in water by reducing the strength of intramolecular hydrogen bond interactions. The proton association ratio between catechol and acetyl group was measured through ¹ H NMR spectroscopy to calculate the degree of catechol conjugation (DOC _cat ) in CBP, which was found to be about 7% (Figure 3) reference).

Additionally, the DOC _cat of CBP was measured from the UV-Vis absorption peak at 280 nm using the HCA absorption peak (see [Figure 4]). This result indicates that less than 4% of the amino groups of chitosan react with HCA to form amides combined with 3,4-dihydroxyhydrocinnamic acid groups. Additionally, the FT-IR spectrum of CBP showed peaks at 3,353 cm ^-1 and 1,632 cm ^-1 corresponding to the hydroxy group, amine group, and carbonyl group of amide, respectively ([Figure 5]).

(2) Mortar flow

[Figure 6] is a graph showing the flow value of a mortar composition containing fine steel slag aggregate and CBP. N100, which consists of only NS fine aggregate, had the lowest flow value of 165mm. The flow value of BS50 was found to be about 167mm, which is similar to N100. The flow value of FS50 was about 185mm, which was 12.1% higher than that of N100.

Mortar flow increased with the addition of CBP to whatever fine aggregate was used. The flow value (including CBP and NS) of PN100 was about 176 mm, which was about 6.6% higher than that of N100. The flow value of the composition using CBP and steel slag fine aggregate was about 187 to 200 mm, which was about 10.4 to 11.9% higher than the flow of the mixture without CBP. As a result, it was found that the fluidity of the mortar composition was further improved by adding CBP when steel slag fine aggregate was mixed compared to mortar using only natural fine aggregate.

(3) Compressive strength

[Figure 7] shows the change in compressive strength by age of cement mortar mixture test specimens using steel slag fine aggregate and CBP. N100 and BS50 had similar compressive strengths at 42.8 MPa at 7 days of age, and FS50 was 47.5 MPa, 10.9% higher than N100. This increase in strength is analyzed to be due to the high density and low absorption rate of FS. The compressive strengths of N100 and BS50 were similar to those of PN100 and PBS50, respectively. However, the 7-day compressive strengths of PBF50 and PFS50 were lower than those of BF50 and FS50, respectively.

The compressive strength of N100 and BS50 at 28 days was also similar at 45.0 MPa. The 28-day compressive strengths of BF50 and FS50 were 49.5 and 55.3 MPa, respectively, which were 11.2% and 24.2% higher than N100, respectively.

However, the compressive strength of compositions using CBP showed a completely different trend. The compressive strength of PN100 at 28 days of age was about 48.7 MPa, which was about 9.4% higher than that of N100. The compressive strength of PBS50 at 28 days of age was 46.0 MPa, which was similar to that of BS50 (45.9 MPa). In contrast, the 28-day compressive strengths of PBF50 and PFS50 were 44.5 and 42.9 MPa, respectively, which were 10.1% and 22.4% lower than those of BF50 and FS50, respectively. The low compressive strength of PBF50 and PFS50 may be due to the weak compatibility between CBP and FS. [Figure 8] shows SEM images of the BS sample and the FS sample before and after immersion in the CBP solution for 7 days. The surface of the BS sample does not change after immersion in the CBP solution. However, numerous cracks are observed on the surface of the FS sample after immersion in the CBP solution. Therefore, BS is confirmed to be more suitable than FS in terms of compressive strength of cement mortar compositions to which CBP is added.

The compressive strength of the mortar composition at 56 days showed a similar trend to the compressive strength at 28 days. FS50 showed the highest 56-day compressive strength of 55.9 MPa. However, PBF50 and PFS50 showed 56-day compressive strengths of 44.7 and 45.5 MPa, respectively, which were 12.6% and 20.0% lower than BF50 and FS50, respectively. In addition, PN100 and PBS50 showed compressive strengths of 51.3 MPa and 49.9 MPa at 56 days, respectively, showing higher compressive strengths than N100 (45.5 MPa) and BS50 (49.2 MPa).

(4) Split tensile strength

[Figure 9] shows the splitting tensile strength of cement mortar composition test specimens at 28 days of age. The tensile strength of N100 was 2.51 MPa, but the tensile strength of PN100 was 3.03 MPa, which was 20.7% higher than that of N100. Additionally, the 28-day tensile strength of PBS50 (3.22 MPa) was slightly higher than that of BS50 (2.94 MPa).

However, the tensile strengths of BF50 and FS50 were found to be 3.48 MPa and 3.42 MPa, respectively. In contrast, the tensile strengths of PBF50 and PFS50 were shown to be 3.28 MPa and 2.55 MPa, respectively, showing that when BF or FS is used as a fine aggregate, the composition to which CBP is added The tensile strength was 5.7% to 25.4% lower than when CBP was not added.

(5) Carbonation depth

[Figure 10] shows the carbonation depth measured after accelerated carbonation of cement mortar composition test specimens for 28 days. The carbonation depth of N100 was about 0.89 mm. The carbonation depth of PN100 is about 0.54 mm, which is about 39.3% lower than that of N100. It is believed that the shallow carbonation depth of PN100 (i.e., greater carbonation resistance) is due to its greater compressive strength than N100.

BS50 showed a carbonation depth of up to 1.33 mm. The carbonation depth of BF50 and FS50 was 0.96 mm and 0.93 mm, respectively, which was lower than that of BS50. However, PBS50 showed similar compressive strength to BS50 at 56 days, but the carbonation depth was 0.59 mm, which was significantly lower than BS50 (55.6%). This is believed to be because the products formed by the reaction between BS and CBP contributed to making the cement hardening matrix more dense. [Figure 11] is an SEM image of BS50 and PBS50. The surface of PBS50 is relatively denser than that of BS50. Considering that the compressive strengths of both compositions (BS50 and PBS50) at 58 days were high, above 49 MPa, the increase in hardness of the hardened cement matrix did not affect the strength of the cement mortar composition, but effectively prevented the penetration of carbon dioxide gas. It can be said that it was prevented.

(6) Chloride ion permeability

[Figure 12] shows the total charge passed for each test example of the cement mortar composition at 28 days of age. The total amount of charge passing through N100 was the highest (9030 C), which was 11.0% higher than PN100 (8028 C). The total charge passing through BS50, BF50, and FS50 was 7331 C, 7172 C, and 6769 C, respectively, which were 18.8-25.3% lower than that of N100.

The total charge passing through the sample using steel slag fine aggregate and CBP was approximately 5741~6050 C, which was 24.6~28.4% lower than that of PN100. The total charge passing through the sample was carefully reduced after addition of CBP. In particular, when steel slag aggregate and CBP were used, the chloride ion penetration resistance of the mortar composition increased.

The above test results can be summarized as follows.

(1) The flow value of the cement mortar composition tends to increase with the addition of CBP.

(2) The compressive strength of PN100 and PBS50 at 56 days of age was higher than that of N100 and BS50. However, the compressive strengths of PBF50 and PFS50 were lower than BF50 and FS50, respectively. Therefore, BS is more effective than FS in improving the compressive strength of cement mortar compositions using CBP and steel slag fine aggregate.

(3) Compressive and tensile strengths were improved when CBP was added to samples using NS or BS. However, in samples with FS, the tensile strength decreased after addition of CBP.

(4) The carbonation depth of PBS50 is 0.59 mm, which is significantly lower than that of BS50.

(5) After adding CBP, the total amount of charge passing through the sample decreased. The chloride ion penetration resistance of mortar samples increased when both CBP and steel slag fine aggregates were used.

Among the test examples in which CBP and steel slag were applied together, PBS50 and PBF50 had a mortar flow of 175 to 200 mm, a compressive strength of 45 MPa or more at 56 days, a splitting tensile strength of 3 MPa or more at 28 days, an accelerated carbonation depth of 1.0 mm or less, and an age of 28 days. All physical properties of chloride ion permeability below 6000 C are met.

From the above results, it is confirmed that as-manufactured CBP is a promising material that can improve the physical properties of cement mortar and is highly compatible with cement composites containing BS aggregate.

Although the present invention has been described in relation to test examples as mentioned above, various modifications and variations are possible without departing from the gist of the present invention, and can be used in various fields. Accordingly, the scope of the present invention includes modifications and variations falling within the true scope of the foregoing invention.

Not applicable

Claims (8)

A mortar composition containing cement, fine aggregate and mixing water,
The mixing water contains 5 to 10 wt% of chitosan-based polymer (CBP) solution,
A cement mortar composition, characterized in that the fine aggregate includes steel slag fine aggregate.
In paragraph 1:
The CBP is a cement mortar composition characterized in that the degree of deacetylation is 75% to 85%.
In paragraph 2,
The CBP is between chitosan, hydrocaffeic acid (HCA), and 1-Ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC). A cement mortar composition characterized by being synthesized through an amide coupling reaction.
In paragraph 1:
The CBP solution is a cement mortar composition characterized in that 450 to 550 mg of CBP is dissolved per 1,000 ml of water.
In paragraph 1:
A cement mortar composition characterized in that the fine aggregate is mixed with 50 vol% or less of steel slag (excluding 0 vol%) and conforms to the standard particle size distribution range of fine aggregate.
In paragraph 5,
A cement mortar composition characterized in that the steel slag is one or more of blast furnace slag (BS) or ferronickel slag (FS).
In any one of paragraphs 1 to 6,
The cement is mixed at 320 to 350 kg per 1 m3 of unit volume,
The fine aggregate is mixed at 700 to 750 kg per 1㎥ of unit volume,
A cement mortar composition, characterized in that the mixing water is mixed according to a water-cement ratio of 45 to 50 wt%.
In paragraph 7:
Mortar flow 175-200 mm;
Age 56 days Compressive strength 45 MPa or more;
Age: 28 days, splitting tensile strength: 3 MPa or more;
Accelerated carbonation depth of 1.0 mm or less; and
Age: 28 days Chloride ion permeation: 6000 C or less; A cement mortar composition characterized in that the physical properties of