Glass fiber modified inorganic cementing material as well as preparation method and application thereof

Abstract

The invention provides a glass fiber modified inorganic cementing material as well as a preparation method and application thereof, and belongs to the technical field of inorganic cementing materials. The preparation method comprises the following steps: uniformly mixing an inorganic ion oligomer solution with nano silicon dioxide to obtain a suspension; and adding a certain amount of glass fiber into the suspension, and uniformly mixing to obtain the glass fiber modified inorganic cementing material. Compared with an unmodified inorganic cementing material, the glass fiber modified inorganic cementing material has the advantages that the contractility and the brittleness are greatly reduced, and the repair efficiency of the inorganic composite material based on oligomer polymerization as the cementing material for repairing larger cracks is remarkably improved; and the application range of the inorganic composite material in actual constructional engineering and repair engineering is widened.

Description

Technical Field

[0001] This invention relates to the field of inorganic cementitious materials technology, specifically to a glass fiber modified inorganic cementitious material, its preparation method, and its application. Background Technology

[0002] With the accelerating pace of modernization, various engineering projects benefiting the country and its people have been put into construction. However, as time goes by, building structures are prone to deterioration and cracking under the long-term influence of loads and environmental factors. If effective measures are not taken to address this, external corrosive substances can penetrate, and the initial cracks will gradually expand into large cracks that affect structural performance and strength, thus causing irreversible damage to the building's suitability and durability.

[0003] Research indicates that among my country's existing reservoirs and dams, cracks are the most serious hidden danger and problem. If these issues are not properly addressed, they will inevitably cause enormous losses. According to statistics from the American Society of Civil Engineers, cracks are the most pressing problem affecting aging bridges in the United States that require repair. Therefore, developing repair materials suitable for cracks in various building structures is an urgent task.

[0004] The inventors' preliminary research showed that the novel inorganic composite material prepared from inorganic ionic oligomers and nano-silica exhibits excellent flowability in the early stages of curing, offering numerous advantages over traditional cementitious materials. It demonstrates good repair performance when used to repair small cracks in building structures. However, due to the material's shrinkage during drying and curing, it is prone to cracking when used to repair larger cracks. Multiple grouting operations are required to ensure sufficient solidification products effectively fill the cracks, resulting in low repair efficiency. Therefore, this invention aims to modify this inorganic composite material to further enhance its performance, making it suitable for repairing larger cracks. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a glass fiber-modified inorganic cementitious material, its preparation method, and its applications. This invention modifies an inorganic composite material obtained by cross-linking polymerization of oligomers using glass fibers. Before modification, the composite material undergoes a certain degree of volume shrinkage during drying due to solvent evaporation. When this shrinkage deformation is externally constrained, tensile stress is generated internally, leading to material cracking. The addition of glass fibers acts like implanting microscopic "reinforcing ribs" into the composite matrix. On one hand, it acts as a filler to offset some of the volume shrinkage; on the other hand, it inhibits crack propagation through anchoring, improving the material's toughness. Therefore, the shrinkage and brittleness of the modified composite material are significantly improved, thus solving the problem of low efficiency in repairing large cracks.

[0006] To achieve the above objectives, the specific technical solution of the present invention is as follows:

[0007] In a first aspect, the present invention provides a method for preparing a glass fiber modified inorganic cementitious material, comprising the following steps:

[0008] An inorganic ionic oligomer solution was mixed evenly with nano-silica to obtain a suspension; a certain amount of glass fiber was added to the suspension and mixed evenly to obtain a glass fiber modified inorganic cementitious material.

[0009] Furthermore, the length of the glass fiber is 0.1-5 mm.

[0010] Furthermore, the amount of glass fiber added is 1-6 g / L.

[0011] Furthermore, the molar ratio of the nano-silica to the inorganic ionic oligomer is 0.3-5:1.

[0012] Furthermore, the inorganic ionic oligomer solution is obtained by reacting inorganic salts and inorganic acids in a solvent with a relatively low permittivity, followed by end-capping with an organic small-molecule amine compound.

[0013] Further, the inorganic salt includes chloride and / or nitrate salts of at least one metal selected from calcium, magnesium, strontium, barium, aluminum, lithium, chromium, iron, cobalt, nickel, copper, zinc, silver, cadmium, lead, and lanthanides; the inorganic acid is at least one selected from carbon dioxide gas, carbonic acid, phosphoric acid, sulfuric acid, and titanic acid; the solvent with a relatively low permittivity is a solvent with a relative permittivity ≤35; the organic small molecule amine compound includes triethylamine, triethanolamine, ethanolamine, diethylamine, or arginine.

[0014] Furthermore, the solvent with a relatively low permittivity includes at least one of methanol, ethanol, ethylene glycol, glycerol, diethylene glycol, triethylene glycol, diethylene glycol dimethyl ether, and tetraethylene glycol.

[0015] Furthermore, the concentration of the inorganic salt in the reaction system is 1-120 mmol / L; the concentration of the inorganic acid in the reaction system is 1-70 mmol / L; and the molar ratio of the organic small molecule amine compound to the inorganic salt is 5-100:1.

[0016] Furthermore, the nano-silica is silica powder or silica gel with a particle size ≤100 nm.

[0017] Secondly, the present invention provides a glass fiber modified inorganic cementitious material prepared by the method described above. The addition of glass fiber improves the shrinkage and cracking problems of inorganic composite materials based on oligomer polymerization when repairing large cracks, and broadens the application range of the inorganic composite material in practical engineering.

[0018] Thirdly, the present invention provides the application of the glass fiber modified inorganic cementitious material in building and repair engineering.

[0019] Compared with the prior art, the advantages of the present invention are:

[0020] 1. The glass fiber modified inorganic cementitious material provided by the present invention has good fluidity and strong groutability. When grouting reinforcement is carried out, the grout can reach the depth of the crack for effective consolidation.

[0021] 2. The glass fiber modified inorganic cementitious material provided by this invention has significantly improved shrinkage and brittleness compared with the inorganic composite material before modification, which improves the applicability of inorganic composite material to different repair projects and can provide more reasonable and efficient repair solutions for different repair needs.

[0022] 3. The glass fiber modified inorganic cementitious material provided by this invention is green, environmentally friendly, not easy to age, not easy to breed bacteria, and has good compatibility with the inorganic matrix.

[0023] 4. The glass fiber modified inorganic cementitious material provided by this invention uses low-cost raw materials, has good economic applicability, and has simple operation steps, making it highly operable and promising for practical engineering applications. Attached Figure Description

[0024] Figure 1 Comparison of the appearance of the cured inorganic cementitious material products before (right) and after (left) modification with glass fiber;

[0025] Figure 2 The images show the curing effects after modification with different amounts and lengths of glass fiber;

[0026] Figure 3 This is a diagram of the bonding and repair of weathered rock blocks in Example 3;

[0027] Figure 4 Figure a shows the effect of repairing a rock fragment with inorganic composite material in Comparative Example 1. Figure 4 Figure b shows the effect of the modified inorganic cementitious material used in Example 3 for repairing the gap in the rock block. Detailed Implementation

[0028] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] This invention provides a method for preparing glass fiber modified inorganic cementitious material, comprising the following steps: mixing an inorganic ionic oligomer solution with nano-silica to obtain a suspension; adding a certain amount of glass fiber to the suspension and mixing it evenly to obtain glass fiber modified inorganic cementitious material.

[0030] In some examples, the length of the glass fiber is 0.1-5 mm; the amount of glass fiber added is 1-6 g / L.

[0031] In some examples, the molar ratio of the nano-silica to the inorganic ionic oligomer is 0.3-5:1.

[0032] In some examples, the inorganic ionic oligomer solution is obtained by reacting an inorganic salt and an inorganic acid in a solvent with a relatively low permittivity, followed by end-capping with an organic small-molecule amine compound.

[0033] In some examples, the inorganic salt includes chloride and / or nitrate salts of at least one metal selected from calcium, magnesium, strontium, barium, aluminum, lithium, chromium, iron, cobalt, nickel, copper, zinc, silver, cadmium, lead, and lanthanides; the inorganic acid is at least one selected from carbon dioxide gas, carbonic acid, phosphoric acid, sulfuric acid, and titanic acid; the solvent with a relatively low permittivity is a solvent with a relative permittivity ≤35, specifically at least one selected from methanol, ethanol, ethylene glycol, glycerol, diethylene glycol, triethylene glycol, diethylene glycol dimethyl ether, and tetraethylene glycol; the organic small molecule amine compound includes triethylamine, triethanolamine, ethanolamine, diethylamine, or arginine.

[0034] In some examples, the concentration of the inorganic salt in the reaction system is 1-120 mmol / L; the concentration of the inorganic acid in the reaction system is 1-70 mmol / L; and the molar ratio of the organic small molecule amine compound to the inorganic salt is 5-100:1.

[0035] In some examples, the nano-silica is silica powder or silica gel with a particle size ≤100 nm.

[0036] Example 1

[0037] A glass fiber modified inorganic cementitious material is prepared by the following steps:

[0038] (1) Dissolve 0.221 g of calcium chloride dihydrate in 60 mL of anhydrous ethanol and stir until the solution is clear and transparent. Then add 4.2 mL of triethylamine to the solution and mix well. Continue to add 40 mL of 25 mM phosphoric acid solution (solvent is ethanol) to the mixed solution and stir magnetically for 2 h at room temperature to obtain calcium phosphate oligomer solution.

[0039] (2) Add 60 mL of 2.5 g / L nano silica gel solution to the calcium phosphate oligomer solution and continue stirring for 40 min to obtain a composite suspension in which calcium phosphate oligomer and nano silica are uniformly mixed.

[0040] (3) Add 0.3 g of glass fiber with a length of 1 mm to the suspension and mix well. Then, centrifuge at 8000 g for 15 min. After discarding the supernatant, obtain the glass fiber modified inorganic cementitious material. Dry the glass fiber modified inorganic cementitious material under natural conditions to obtain the cured product ( Figure 1 (Left), and then combined with the cured product of unmodified inorganic cementitious material ( Figure 1 On the right, by centrifuging and drying the composite suspension obtained in step (2), it can be seen that the volume loss rate of the cured product after modification is significantly reduced compared with that of the cured product before modification. This indicates that the overall shrinkage of the modified material is well suppressed, which can greatly improve the filling efficiency of the material when used to repair larger or wider cracks. The unmodified inorganic cementitious material is obtained by centrifuging the composite suspension with the same solid content in step (2) at 8000 g for 15 min in a centrifuge, removing the supernatant, and then drying it under natural conditions.

[0041] Example 2

[0042] A glass fiber modified inorganic cementitious material is prepared by the following steps:

[0043] (1) Dissolve 0.221 g of calcium chloride dihydrate in 100 mL of anhydrous ethanol and stir until the solution is clear and transparent. Then add 4.2 mL of triethylamine to the solution and mix well. Continue to pass carbon dioxide gas at 100 mL / min into the mixed solution and stir magnetically until the solution changes from turbid to transparent or semi-transparent to obtain calcium carbonate oligomer solution.

[0044] (2) Add 0.15 g of nano-silica powder with a particle size of 7-40 nm to the calcium carbonate oligomer solution and continue stirring for 40 min to obtain a composite suspension in which calcium carbonate oligomer and nano-silica are uniformly mixed.

[0045] (3) Add a certain amount (0.1 g, 0.2 g, 0.3 g, 0.4 g) of glass fiber (1 mm, 3 mm, 5 mm in length) to the suspension respectively, mix thoroughly, and then centrifuge at 8000 g for 10 min. After discarding the supernatant, inorganic cementitious materials modified with glass fiber of different amounts and lengths are obtained. The inorganic cementitious materials modified with glass fiber are dried under natural conditions to obtain a comparison of the appearance of the solidification products of each control group as shown in the figure. Figure 2 As shown in the figure, for the same fiber length, the density of the consolidated product first increases and then decreases with the increase of fiber addition, with the best effect at an addition amount of 3 g / L. This is because when the fiber addition amount is small, its ability as a filler to offset the volume shrinkage during drying is reduced, and the anchoring effect of the fiber is also weak. Therefore, the material is prone to cracking during volume shrinkage, thus affecting the overall density. When the fiber addition amount is too large, most of the inorganic cementitious material that plays a cementing role is replaced by glass fiber, and the glass fibers cannot bond together, ultimately leading to a loose material. At the same addition amount, the density of the consolidated product weakens with the increase of glass fiber length. This is because the longer the fiber, the easier it is for them to entangle and clump together during stirring, forming local stress concentration points and defects, rather than a uniformly dispersed reinforcing phase. Moreover, excessively long fibers will exert a large restraining force on the surrounding matrix like "nails" during the material curing and shrinkage process, which will instead cause microcracks and weaken the overall integrity of the material.

[0046] Example 3

[0047] Application of a glass fiber modified inorganic cementitious material in building or repair engineering. This embodiment describes the bonding and repair of weathered rock blocks with uneven fracture surfaces, following these steps:

[0048] (1) Dissolve 0.442 g of calcium chloride dihydrate in 200 mL of anhydrous ethanol and stir until the solution is clear and transparent. Then add 8.4 mL of triethylamine to the solution and mix well. Continue to pass carbon dioxide gas at 80 mL / min into the mixed solution and stir magnetically until the solution changes from turbid to transparent or semi-transparent to obtain calcium carbonate oligomer solution.

[0049] (2) Add 0.3 g of nano-silica powder with a particle size of 7-40 nm to the calcium carbonate oligomer solution and continue stirring for 1.5 h to obtain a composite suspension in which calcium carbonate oligomer and nano-silica are uniformly mixed.

[0050] (3) Add 0.6 g of glass fiber with a length of 1 mm to the suspension and mix evenly. Then place it in a centrifuge and centrifuge at 8000 g for 20 min. After discarding the supernatant, the inorganic cementitious material modified by glass fiber is obtained.

[0051] (4) Apply the inorganic cementing material evenly to the cross-section of the weathered rock block, then align another broken block with the crack, compact it, and tie it tightly with a rubber band. Place it under natural conditions to dry. After 3 days, the broken rock blocks will be bonded together as a whole. Figure 3 ).

[0052] Comparative Example 1

[0053] The application of a novel inorganic composite material based on oligomer polymerization in building or repair engineering involves the following steps:

[0054] (1) Dissolve 0.442 g of calcium chloride dihydrate in 200 mL of anhydrous ethanol and stir until the solution is clear and transparent. Then add 8.4 mL of triethylamine to the solution and mix well. Continue to pass carbon dioxide gas at 80 mL / min into the mixed solution and stir magnetically until the solution changes from turbid to transparent or semi-transparent to obtain calcium carbonate oligomer solution.

[0055] (2) Add 0.3 g of nano-silica powder with a particle size of 7-40 nm to the calcium carbonate oligomer solution and continue stirring for 1.5 h to obtain a composite suspension in which calcium carbonate oligomer and nano-silica are uniformly mixed.

[0056] (3) The suspension was centrifuged in a centrifuge at 8000 g speed, and the supernatant was discarded to obtain a gel-like complex.

[0057] (4) Apply the gel-like composite evenly to the gap in the weathered rock block, and then place it under natural conditions to dry. After 36 hours, the repaired rock block is obtained as shown. Figure 4 As shown in Figure a, the gel-like composite shrinks and cracks during the drying and curing process. The cured repair material does not completely cover the gap in the rock block, so the rock block needs to be repaired a second time.

[0058] In contrast, the glass fiber-modified inorganic cementitious material obtained in step (3) of Example 3 was uniformly applied to the gap in the weathered rock block, and then placed under natural conditions to dry. After 36 hours, the repaired rock block was obtained as shown in the figure. Figure 4 As shown in Figure b, the modified inorganic cementitious material did not experience significant cracking or volume shrinkage during the drying process. The cured repair material completely filled the gap in the rock block, eliminating the need for secondary repair. This comparison shows that the glass fiber-modified inorganic cementitious material improved the repair efficiency of the original inorganic composite material in practical applications.

[0059] The above detailed embodiments describe the implementation of the present invention; however, the present invention is not limited to the specific details described in the above embodiments. Within the scope of the claims and technical concept of the present invention, various simple modifications and changes can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

Claims

1. A method for preparing a glass fiber modified inorganic cementitious material, characterized in that, Includes the following steps: An inorganic ionic oligomer solution was mixed evenly with nano-silica to obtain a suspension; a certain amount of glass fiber was added to the suspension and mixed evenly to obtain a glass fiber modified inorganic cementitious material.

2. The method for preparing the glass fiber modified inorganic cementitious material according to claim 1, characterized in that, The glass fiber has a length of 0.1-5 mm.

3. The method for preparing glass fiber modified inorganic cementitious material according to claim 2, characterized in that, The amount of glass fiber added is 1-6 g / L.

4. The method for preparing the glass fiber modified inorganic cementitious material according to claim 1, characterized in that, The molar ratio of the nano-silica to the inorganic ionic oligomer is 0.3-5:

1.

5. The method for preparing the glass fiber modified inorganic cementitious material according to claim 4, characterized in that, The inorganic ionic oligomer solution is obtained by reacting inorganic salts and inorganic acids in a solvent with a relatively low permittivity, followed by end-capping with small organic molecule amine compounds.

6. The method for preparing glass fiber modified inorganic cementitious material according to claim 5, characterized in that, The inorganic salts include chlorides and / or nitrates of at least one metal selected from calcium, magnesium, strontium, barium, aluminum, lithium, chromium, iron, cobalt, nickel, copper, zinc, silver, cadmium, lead, and lanthanides; the inorganic acids are at least one selected from carbon dioxide gas, carbonic acid, phosphoric acid, sulfuric acid, and titanic acid; the solvents with relatively low permittivity are solvents with a relative permittivity ≤35; the small organic molecule amine compounds include triethylamine, triethanolamine, ethanolamine, diethylamine, or arginine.

7. The method for preparing the glass fiber modified inorganic cementitious material according to claim 5, characterized in that, The concentration of the inorganic salt in the reaction system is 1-120 mmol / L; the concentration of the inorganic acid in the reaction system is 1-70 mmol / L; and the molar ratio of the organic small molecule amine compound to the inorganic salt is 5-100:

1.

8. The method for preparing the glass fiber modified inorganic cementitious material according to claim 1, characterized in that, The nano-silica is silica powder or silica gel with a particle size ≤100 nm.

9. Glass fiber modified inorganic cementitious material prepared by the method according to any one of claims 1-8.

10. The application of the glass fiber modified inorganic cementitious material according to claim 9 in building and repair engineering.

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