Cement-based material with high chloride ion erosion resistance and preparation method of cement-based material

Abstract

The invention discloses a cement-based material with high chloride ion erosion resistance and a preparation method thereof.The cement-based material is composed of a leaf derived carbon material, mixing water and Portland cement, and the preparation method comprises the following steps that waxberry leaves serve as raw materials and are ground to obtain waxberry leaf powder, and the waxberry leaf powder and water are mixed according to the mass ratio to obtain a solid-liquid mixture; heating the solid-liquid mixture at 180-210 DEG C for 16-24 hours by adopting a hydrothermal method to obtain an initial product, and drying the initial product to obtain a black powdery leaf derived carbon material; uniformly mixing the leaf derived carbon material with Portland cement according to a mass ratio to obtain a blend; and mixing the blend with mixing water according to a mass ratio to obtain the cement-based material with high chloride ion erosion resistance. The cement-based material with high chloride ion erosion resistance is simple to prepare, low in cost and environment-friendly, and the chloride ion curing performance and chloride ion penetration resistance of the cement-based material can be remarkably improved.

Description

Technical Field

[0001] The invention belongs to the technical field of building materials and relates to a cement-based material with high resistance to chloride ion corrosion and a preparation method thereof. Background Art

[0002] With the rapid development of global infrastructure construction, cement-based materials are increasingly used in marine engineering and other fields. However, marine engineering structures are often exposed to chloride-containing environments, and chloride ion corrosion has become one of the main factors affecting their durability. Chloride ions can penetrate into cement-based materials through capillary pores and cracks, causing steel bar corrosion, and then causing concrete cracking, spalling and other structural damage. This not only increases maintenance costs, but also seriously threatens the safety and service life of the structure.

[0003] In recent years, scientists have significantly improved the chloride ion corrosion resistance of cement-based materials in a variety of ways. For example, mineral admixtures (such as fly ash, slag, etc.) can reduce the penetration of chloride ions by filling micropores and increasing the density of materials, but the strength of cement-based materials may be lost at higher dosages; polymer materials prevent chloride ions from contacting the steel bars inside cement-based materials by forming a protective film, but their preparation process is relatively complicated; nanomaterials can optimize the pore structure of materials at a microscopic scale, improve their impermeability and self-healing ability, but they still face the challenges of high cost and poor dispersion.

[0004] The use of leaf-derived carbon materials from biomass raw materials such as leaves is an emerging means to enhance the durability of cement-based materials due to its environmentally friendly, easy preparation, and low cost. Leaf-derived carbon materials have a high specific surface area and a porous structure. By adding leaf-derived carbon materials, chloride ions can be effectively adsorbed and their penetration can be prevented. However, leaf-derived carbon materials usually require high-temperature carbonization to be produced, which consumes a lot of energy and seriously affects their large-scale preparation.

[0005] In summary, the development of cement-based materials with high resistance to chloride ion corrosion based on leaf-derived carbon materials still has problems such as high energy consumption in the preparation process. Therefore, it is necessary to optimize its preparation method and promote it to engineering practice to improve the resistance of cement-based materials to chloride ion corrosion. Summary of the invention

[0006] The purpose of the present invention is to provide a cement-based material with high resistance to chloride ion corrosion and a preparation method thereof, so as to solve the problems that the cement-based material has low durability and the method for improving its durability is complex to prepare, high cost and low efficiency.

[0007] To achieve the above object, the present invention provides the following technical solution: a cement-based material with high resistance to chloride ion corrosion and a preparation method thereof, which is composed of leaf-derived carbon material, mixing water, and silicate cement. The specific preparation steps are as follows:

[0008] Step 1: using bayberry leaves as raw materials, grinding the bayberry leaves to obtain bayberry leaf powder, and mixing the bayberry leaf powder with water according to a mass ratio to obtain a solid-liquid mixture;

[0009] Step 2: using a hydrothermal method, heating the solid-liquid mixture described in step 1 at 180-210° C. for 16-24 hours to obtain an initial product, and drying the initial product to obtain a black powdery leaf-derived carbon material;

[0010] Step 3: uniformly mixing the leaf-derived carbon material and silicate cement in step 2 according to a mass ratio to obtain a blend;

[0011] Step 4: mixing the blend described in step 3 with mixing water in a certain mass ratio to obtain a cement-based material with high resistance to chloride ion corrosion;

[0012] The mass ratio of the leaf-derived carbon material, mixing water and silicate cement is (0.01-0.1):(0.3-0.5):1.

[0013] Preferably, in step one, the mass ratio of bayberry leaf powder to water is 1:10-50.

[0014] Therefore, the present invention adopts a high chloride ion corrosion resistance cement-based material of the above structure and a preparation method thereof, which has the following beneficial effects:

[0015] (1) Compared with the traditional method of improving the chloride ion corrosion resistance of cement-based materials, the high chloride ion corrosion resistance cement-based material and its preparation method provided by the present invention have the characteristics of simple preparation, low cost, and environmental protection, and can significantly improve the chloride ion curing performance and chloride ion penetration resistance of cement-based materials.

[0016] (2) Compared with traditional leaf-derived carbon materials, the leaf-derived carbon materials prepared by the present invention can be successfully prepared at a lower temperature and without the addition of other additional chemical reagents. In addition, the leaf-derived carbon materials prepared by the present invention contain a large number of oxygen-containing functional groups on their surfaces, which help them form a stable dispersion system in the cement matrix.

[0017] (3) Compared with leaf-derived carbon materials prepared using other leaves as raw materials, bayberry leaves contain a higher proportion of lignin, cellulose and hemicellulose. These components can be well converted into carbon materials with stable chemical structures during the hydrothermal reaction, with high porosity and specific surface area, and can provide a large number of nucleation sites for cement hydration products. In addition, the carbon content of bayberry leaves is relatively high, which can improve its carbonization efficiency during the hydrothermal reaction compared to other leaves, thereby improving the preparation efficiency and economy of the material.

[0018] (4) The leaf-derived carbon material added in the present invention can fully exert its nucleation effect in the cement matrix, provide more nucleation sites, promote the nucleation, precipitation and growth of cement hydration products, and thus promote the formation of cement hydration products calcium silicate hydrate (CSH) and calcium aluminate hydrate (AFm phase). CSH can physically adsorb chloride ions through electrostatic force and van der Waals force, and the AFm phase can chemically combine with chloride ions to form Friedel salt. Therefore, the cement-based material after adding the leaf-derived carbon material can form more CSH and Friedel salt, thereby significantly improving its chloride ion curing performance. In addition, the hydration products generated by the cement-based material after adding the leaf-derived carbon material are intertwined and evenly distributed, making the internal structure of the hardened cement paste more compact and the internal pore structure more refined, thereby improving the chloride ion corrosion resistance of the cement-based material.

[0019] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a preparation flow chart of an embodiment of the present invention.

[0021] Figure 2 This is the FTIR graph of the leaf-derived carbon material prepared in the embodiment of the present invention.

[0022] Figure 3 is a SEM image of the leaf-derived carbon material prepared in the embodiment of the present invention.

[0023] Figure 4 Graph showing particle size distribution of leaf-derived carbon materials prepared in an embodiment of the present invention. DETAILED DESCRIPTION

[0024] The present invention will be further described below. It should be noted that this embodiment is based on the technical solution and provides a detailed implementation method and a specific operation process, but the present invention is not limited to this embodiment.

[0025] Example

[0026] A cement-based material with high resistance to chloride ion corrosion and a preparation method thereof, comprising leaf-derived carbon material, mixing water and silicate cement. The specific preparation steps are as follows: Figure 1 As shown:

[0027] Step 1: Grind bayberry leaves to obtain bayberry leaf powder, and mix the bayberry leaf powder with water at a mass ratio of 1:10 to obtain a solid-liquid mixture;

[0028] Step 2: using a hydrothermal method, heating the solid-liquid mixture described in step 1 at 200° C. for 18 hours to obtain an initial product, and drying the initial product to obtain a black powdery leaf-derived carbon material;

[0029] Step 3: uniformly mixing the leaf-derived carbon material and silicate cement in step 2 according to a mass ratio to obtain a blend;

[0030] Step 4: Mix the blend described in step 3 with mixing water in a mass ratio of 0.1:0.5:1, and stir for 5 minutes to obtain a cement-based material with high resistance to chloride ion corrosion.

[0031] like Figure 2 As shown in the figure, the surface of the prepared leaf-derived carbon material contains a large number of oxygen-containing functional groups, including 1593 cm -1 The peak at 1348 cm is attributed to the C=C / C=0 bond. -1 The peak at 1119 cm is attributed to the C-OH bond. -1 The peak at is attributed to the COC bond.

[0032] like Figure 3 As shown, the prepared leaf-derived carbon material has a rough surface and contains a large number of spherical particles.

[0033] like Figure 4 As shown, the prepared leaf-derived carbon material has a particle size range of 1 to 100 μm, mainly 10 μm particles.

[0034] Comparative Example

[0035] The difference from the embodiment is that: no leaf-derived carbon material is added, and the cement-based material is obtained by directly mixing silicate cement with mixing water.

[0036] Test example

[0037] After the cement-based materials of the embodiment and the comparative example were cured for 28 days, the chloride ion curing performance of the cement-based materials after curing was measured according to the method specified in JGJ / T 322-2013 "Technical Specification for the Detection of Chloride Ion Content in Concrete". The chloride ion permeability resistance coefficient of the cement-based materials after curing was measured according to the method specified in GB / T50082-2009 "Standard for Test Methods for Long-term Performance and Durability of Ordinary Concrete". The test results are shown in Table 1.

[0038] Table 1 Compressive strength and chloride ion permeability coefficient of cement-based materials in Examples and Comparative Examples

[0039]

[0040] As can be seen from Table 1, compared with the comparative example, the chloride ion curing rate of the high chloride ion corrosion resistant cement-based material in the embodiment after curing for 28 days increased by 23.8%. In addition, compared with the comparative example, the chloride ion permeability resistance coefficient of the high chloride ion corrosion resistant cement-based material in the embodiment decreased by 18.4%. Therefore, the high chloride ion corrosion resistant cement-based material provided by the present invention has the characteristics of simple operation and low preparation cost, and can significantly improve the chloride ion curing performance and chloride ion permeability resistance of the cement-based material.

[0041] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A cement-based material with high resistance to chloride ion corrosion and a preparation method thereof, characterized in that: It consists of leaf-derived carbon material, mixing water, and silicate cement. The specific preparation steps are as follows: Step 1: using bayberry leaves as raw materials, grinding the bayberry leaves to obtain bayberry leaf powder, and mixing the bayberry leaf powder with water according to a mass ratio to obtain a solid-liquid mixture; Step 2: using a hydrothermal method, heating the solid-liquid mixture in step 1 at 180-210° C. for 16-24 hours to obtain an initial product, and drying the initial product to obtain a black powdery leaf-derived carbon material; Step 3: uniformly mixing the leaf-derived carbon material and silicate cement in step 2 according to a mass ratio to obtain a blend; Step 4: mixing the blend in step 3 with mixing water according to a mass ratio to obtain a cement-based material with high resistance to chloride ion corrosion; Among them, the mass ratio of the leaf-derived carbon material, mixing water and silicate cement is (0.01-0.1):(0.3-0.5):

1.

2. The high chloride ion corrosion resistance cement-based material and preparation method thereof according to claim 1, characterized in that: In step 1, the mass ratio of bayberry leaf powder to water is 1:10-50.

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