Preparation Method of Ultra-Fine Nano-Scale Active Admixture and Linked Grouting Material

Abstract

The present invention provides a preparation method of ultra-fine nano-scale active admixture and linked grouting material. The grouting material comprises the following components by mass percentage: 25% - 38% of cement, 5% - 14% of glass microspheres, 2 - 5% of silica fume, 5% - 20% of ultra-fine nano-scale active admixture, 2 - 5% of high-strength fibers, 0.1% - 1% of toughening fibers, 0.2% - 0.4% of polycarboxylate water reducer, 0% - 0.02% of defoaming agent, 0% - 0.04% of foaming agent, 28% - 42% of river sand, and 12% - 18% of ground river sand. In the present invention, a composite of ordinary portland cement, industrial gypsum and calcium bicarbonate is added as an activity activator of mineral admixture, which acts together with a high-efficiency water reducer to activate its activity, so that the active components of fly ash and slag powder in the mineral admixture are fully activated, filling various pores formed during the hardening process of the grouting material, reducing the porosity of the grouting material, and the grouting material obtains excellent erosion resistance and durability.

Description

Technical Field

[0001] The present invention relates to the technical field of building materials, and particularly relates to a preparation method of ultra-fine nano-scale active admixtures and linking grouting materials. Background Art

[0002] Cement-based grouting materials have become the main materials in grouting projects due to their wide sources, low prices, and convenient use. However, ordinary cement grouting materials are brittle, with low tensile strength, poor crack resistance, no ductility and brittle failure characteristics. When the water-binder ratio is low, the fluidity is poor, and they cannot meet the requirements of some special grouting. With the progress of society and the rapid development of the admixture industry, people have put forward higher requirements for grouting materials. For example, some steel structure connection sections and steel-concrete structure transition connection sections require high-strength anti-fatigue load connection, and the mixture is required to have ultra-high fluidity to meet the construction needs, and have micro-expansion after hardening to achieve the best connection effect. Therefore, the preparation is difficult and there is no mature product in China. Summary of the Invention

[0003] The present invention provides a preparation method of ultra-fine nano-scale active admixtures and linking grouting materials. Industrial solid wastes such as steel slag, fly ash, slag, marble powder, and granite powder are used in the admixtures, which solves the problem that industrial solid waste admixtures can effectively increase the added value of industrial solid wastes, reduce the preparation cost of ultra-high performance concrete, and at the same time have a beneficial effect on the performance of ultra-high performance concrete.

[0004] The technical solution adopted to achieve the above object of the present invention is as follows:

[0005] An ultra-fine nano-scale active admixture, by weight, the ultra-fine nano-scale active admixture includes 30-50 parts of slag, 20-50 parts of steel slag, 10-50 parts of fly ash, 1-10 parts of marble powder, 2-10 parts of granite powder, 2-8 parts of nano-calcium carbonate, 2-8 parts of nano-silica, and 1-10 parts of activator.

[0006] Further, the ultra-fine nano-scale active admixture includes 40-50 parts of slag, 40-50 parts of steel slag, 20-50 parts of fly ash, 1-5 parts of marble powder, 2-5 parts of granite powder, 2-5 parts of nano-calcium carbonate, 2-5 parts of nano-silica, and 2-6 parts of activator.

[0007] Further, the ultra-fine nano-scale active admixture includes 40 parts of slag, 40 parts of steel slag, 20 parts of fly ash, 3 parts of marble powder, 3 parts of granite powder, 6 parts of nano-calcium carbonate, 6 parts of nano-silica, and 5 parts of activator.

[0008] Further, the marble powder and granite powder are waste powders generated during the cutting of marble and granite in a stone factory, with a specific surface area greater than 680 m 2 / kg and an average particle size less than 35 μm; the use of marble powder and granite powder can reduce the amount of cement used and comprehensively utilize resources; the activator is composed of industrial gypsum and calcium bicarbonate in a weight ratio of 1:1.

[0009] Further, the steel slag is stainless steel slag, with an alkalinity of 1.2 - 2.0, a grain size of 0.5 - 10 μm, and chemical components: silica 20 - 30 wt%, alumina 5 - 10 wt%, iron oxide 10 - 15 wt%, calcium oxide 42 - 50 wt%, magnesium oxide 4 - 6 wt%, potassium oxide 0 - 0.02 wt%, sodium oxide 0.1 - 0.3 wt%, and the rest are other impurities.

[0010] Further, the fly ash is fine solid particles in the flue gas ash generated by the combustion of fuel in a power plant, with a mass percentage content of SiO2 > 50 wt%, a mass percentage content of Al2O3 > 30 wt%, and a residue on a 45 μm square hole sieve < 20%.

[0011] The commonly used activator for fly ash is a single salt activator, which can only simply activate the activity of fly ash and cannot improve the durability of concrete. The activator used in the present invention is composed of industrial gypsum and calcium bicarbonate in a weight ratio of 1:1, with good activation effect, small dosage, and low cost.

[0012] The present invention also provides a preparation method of the above ultra-fine nano-scale active admixture, including the following steps:

[0013] Step 1: According to the required weight parts, add slag, fly ash, and steel slag to a ball mill for grinding; the ball milling time of the ball mill is 30 - 60 min to obtain industrial solid waste powder.

[0014] Step 2: Add marble powder, granite powder, nano-calcium carbonate, and nano-silica to the industrial solid waste powder obtained in Step 1, and continue to start the ball mill for grinding; the ball milling time of the ball mill is 20 - 40 min to obtain nano-modified industrial solid waste powder, that is, ultra-fine nano-scale active admixture.

[0015] The present invention also provides a grouting material containing the above-mentioned ultra-fine nano-scale active admixture. The grouting material comprises the following components by mass percentage: 25% - 38% of cement, 5% - 14% of glass microspheres, 2 - 5% of silica fume, 5% - 20% of ultra-fine nano-scale active admixture, 2 - 5% of high-strength fiber, 0.1% - 1% of toughening fiber, 0.2% - 0.4% of polycarboxylate water reducer, 0% - 0.02% of defoamer, 0% - 0.04% of foaming agent, 28% - 42% of river sand, and 12% - 18% of ground river sand.

[0016] Further, the cement is ordinary Portland cement with a strength grade not lower than 42.5; both the polycarboxylate water reducer and the defoamer are powders. The water reduction rate of the polycarboxylate water reducer is not less than 25%, and the defoamer is an organosilicon type.

[0017] Further, the 28-day activity index of the silica fume is 100 - 106%, the SiO 2 content is not less than 95%, and the average particle size is 0.5 - 3 μm.

[0018] Further, the foaming agent is an amide organic powder that can decompose to produce nitrogen in an alkaline environment; the river sand is obtained by screening natural river sand with a water content of less than 0.1%, and the part with a particle size of 0.15 - 1.18 mm is taken; the ground river sand is obtained by grinding natural river sand, and the average particle size is 0.08 - 0.15 mm.

[0019] Further, the high-strength fiber is copper-plated microfilament steel fiber with an average length of 4 - 8 mm, a diameter of 0.1 - 0.2 mm, and a tensile strength not less than 2850 MPa. The copper-plated microfilament steel fiber of the present invention not only has better mechanical properties but also is high-temperature resistant and corrosion-resistant. When applied in concrete, it can inhibit the shrinkage cracking of concrete throughout its life and improve the crack resistance. At the same time, with the nucleation effect, filling effect, and high activity of the nano-active material and ultra-fine mineral admixture, it can effectively solve the cracking of concrete and improve the density; the copper-plated microfilament steel fiber can form a three-dimensional random support lap system in the concrete, effectively dispersing the concrete shrinkage stress and reducing the cracking risk.

[0020] Further, the toughening fiber is glass fiber with an average length of 50 - 100 μm and a diameter of 5 - 10 μm. Once cracks occur after the concrete hardens, they are likely to expand into through cracks. The glass fiber can reduce the cracks in the concrete and make the crystals generated at the crack sites quickly stable. The glass fiber forms a disordered fiber network in the concrete, which can effectively inhibit the generation of internal cracks and prevent the expansion of cracks under external forces, and can effectively reduce the cracks.

[0021] The present invention also provides a preparation method of the above-mentioned grouting material, comprising the following steps:

[0022] (1) Weigh 25% - 38% of cement, 5% - 14% of glass microspheres, 2 - 5% of silica fume, 5% - 20% of ultra-fine nano-scale active admixture, 2 - 5% of high-strength fiber, 0.1 - 1% of toughening fiber, 0.2% - 0.4% of polycarboxylate water reducer, 0% - 0.02% of defoamer, 0% - 0.04% of foaming agent, 28% - 42% of river sand, and 12% - 18% of ground river sand respectively according to the required mass percentage, and set aside;

[0023] (2) Grind natural river sand in a ball mill to an average particle size of 0.08 - 0.15 mm to obtain ground river sand;

[0024] (3) Dry mix the river sand and ground river sand in a dry mixer for 5 minutes according to the proportions weighed in step (1), and stop the machine;

[0025] (4) Add the cement, glass microspheres, silica fume, ultra-fine nano-scale active admixture, high-strength fiber, and toughening fiber weighed in step (1) to the dry mixer, restart the machine, and continue dry mixing for 5 minutes, then stop the machine;

[0026] (5) Then evenly sprinkle the polycarboxylate water reducer, defoamer, and foaming agent weighed in step (1) into the dry mixer while it is running, and continue dry mixing for 20 minutes to obtain the grouting material;

[0027] (6) Pack the grouting material prepared in step (5) into an inner-lined packaging bag, seal it, and store it.

[0028] Further, the glass microspheres are air-selected ultra-fine fly ash glass microspheres with an average particle size of 1 - 5 μm;

[0029] The glass microspheres of the present invention can greatly reduce the viscosity of the mixture. Its main component is SiO 2 And it exists in the form of vitreous body, having high pozzolanic activity, and can also fill between cement particles to improve strength and durability. The particle size of the nano-calcium carbonate is 100 - 200 nm, and the particle size of the nano-silica is 100 - 150 nm. The weight ratio of nano-silica to nano-calcium carbonate in the present invention is 1:1. Nano-silica and nano-calcium carbonate are ultra-fine mineral admixtures that fill the hydration inside the concrete and provide crystal nucleation points, making the concrete more uniform and dense, and improving the mechanical strength and durability.

[0030] Beneficial effects

[0031] 1. The present invention uses a composite of ordinary Portland cement, industrial gypsum, and calcium bicarbonate as an activator for the activity of mineral admixtures, which acts together with a high-range water reducer to stimulate their activity. As a result, the active components of fly ash and slag powder in the mineral admixtures are further stimulated, filling various pores formed during the hardening process of concrete, thereby increasing the density of concrete, reducing the porosity of concrete, and endowing the concrete with excellent erosion resistance and durability.

[0032] 2. Since the mutual compounding of mineral admixtures of various different sizes will produce a superposition effect, the present invention composes a super high-performance cementitious system by compounding cement with silica fume, glass microspheres, marble powder, and granite powder in a certain proportion, and composes an aggregate system for grouting materials by compounding screened river sand and ground river sand in a certain proportion. At the same time, a polycarboxylate water reducer is used to reduce the water demand of the system, an antifoaming agent is introduced to eliminate harmful bubbles generated during the mixing process of the mixture, a foaming agent is introduced to generate nitrogen in an alkaline environment to inhibit the shrinkage of the grouting material in the plastic stage, and steel fibers are introduced to enhance the toughness of the grouting material. Finally, high fluidity, low viscosity, low shrinkage, high toughness, ultra-high strength, and ultra-high durability of the high-strength anti-fatigue load steel-concrete connection grouting material are achieved under normal temperature conditions. Specific Embodiments

[0033] The following will make a detailed and specific description of the present invention in combination with specific embodiments, but the protection scope of the present invention is not limited to the following embodiments.

[0034] Example 1

[0035] A superfine nano-scale active admixture, by weight, the superfine nano-scale active admixture includes 40 parts of slag, 40 parts of steel slag, 20 parts of fly ash, 5 parts of marble powder, 5 parts of granite powder, 5 parts of nano calcium carbonate, 5 parts of nano silicon oxide, and 5 parts of activator;

[0036] The specific surface area of the granite powder is 750 m 2 / kg, and the average particle size is 25 μm;

[0037] The specific surface area of the marble powder is 720 m 2 / kg, and the average particle size is 28 μm

[0038] The activator is composed of industrial gypsum and calcium bicarbonate in a weight ratio of 1:1.

[0039] The preparation method of the above-mentioned superfine nano-scale active admixture includes the following steps:

[0040] Step 1: According to the required parts by weight, add slag, fly ash, and steel slag to a ball mill for grinding; the ball milling time of the ball mill is 30 - 60 min to obtain industrial solid waste powder;

[0041] Step 2: Add marble powder, granite powder, nano calcium carbonate, and nano silicon dioxide to the industrial solid waste powder obtained in Step 1, and continue to start the ball mill for grinding; the grinding time of the ball mill is 40 min to obtain nano-modified industrial solid waste powder, that is, ultra-fine nano-scale active admixture.

[0042] Example 2

[0043] The grouting material containing the ultra-fine nano-scale active admixture obtained in Example 1, and the grouting material includes the following components by mass percentage: cement 27.8%, glass microspheres 9.5%, silica fume 4.6%, ultra-fine nano-scale active admixture 11.4%, high-strength fiber 2%, toughening fiber 1%, polycarboxylate water reducer 0.38%, defoaming agent 0.01%, foaming agent 0.01%, river sand 30.4%, and ground river sand 12.9%.

[0044] The 28-day activity index of the silica fume is 102%, the SiO 2 content is 98%, and the average particle size is 0.18 μm.

[0045] The defoaming agent is a polysiloxane defoaming agent; the foaming agent is a certain azodicarbonamide organic powder; the particle size of the river sand is 0.15 - 1.18 mm, with continuous gradation and mud content less than 1%; the ground river sand is ground by a ball mill with an average particle size of 0.12 mm.

[0046] The high-strength fiber is copper-plated micro wire steel fiber with an average length of 8 mm, a diameter of 0.15 mm, and a tensile strength of 2850 MPa.

[0047] The toughening fiber is glass fiber with a length of 80 μm and a diameter of 8 μm.

[0048] The preparation method of the above grouting material includes the following steps:

[0049] (1) Weigh cement, glass microspheres, silica fume, ultra-fine nano-scale active admixture, high-strength fiber, toughening fiber, polycarboxylate water reducer, defoaming agent, foaming agent, river sand, and ground river sand according to the required mass percentages and set aside.

[0050] (2) Grind the natural river sand in a ball mill to an average particle size of 0.12 mm to obtain ground river sand.

[0051] (3) Dry mix the river sand and ground river sand in a dry mixer for 5 min according to the proportions weighed in step (1), and then stop the machine.

[0052] (4) Add the cement, glass microspheres, silica fume, ultra-fine nano-scale active admixture, high-strength fiber, and toughening fiber weighed in step (1) to the dry mixer, turn on the machine again, and continue to dry mix for 5 min, then stop the machine.

[0053] (5) Then, uniformly sprinkle the polycarboxylate water reducer, defoamer, and foaming agent weighed in step (1) into the dry mixer in the operating state, and continue dry mixing for 20 min to obtain the grouting material.

[0054] (6) Pack the grouting material obtained in step (5) into an inner-lined packaging bag and store it after sealing.

[0055] Comparative Example 1

[0056] The difference between Comparative Example 1 and Example 1 is only that 7 parts of activator are used.

[0057] Comparative Example 2

[0058] The difference between Comparative Example 2 and Example 1 is only that 3 parts of activator are used.

[0059] Comparative Example 3

[0060] The difference between Comparative Example 3 and Example 1 is only that 1 part of activator is used.

[0061] Comparative Example 4

[0062] The difference between Comparative Example 3 and Example 1 is only that 0 part of activator is used.

[0063] Comparative Example 5

[0064] The difference between Comparative Example 4 and Example 2 is only that 29.3% of cement, 8.0% of glass microspheres, 0.02% of defoamer, and 0% of foaming agent are used.

[0065] Comparative Example 6

[0066] The difference between Comparative Example 5 and Example 2 is only that 3.6% of silica fume and 12.4% of ultra-fine nano-scale active admixture are used.

[0067] Activity excitation test of ultra-fine nano-scale active admixture

[0068] Refer to GB / T 18046-2017 "Ground granulated blast-furnace slag for use in cement, mortar and concrete" to test the activity index of ultra-fine powder.

[0069] Use a test ball mill (SM-500*500) for grinding, and test the performance of the ultra-fine nano-scale active admixture in Example 1 and Comparative Examples 1-4. The results are shown in Table 1 below.

[0070] Table 1

[0071]

[0072] The results show that the activity index of the ultra-fine nano-scale active admixture of the present invention exceeds 90% at 7 days and exceeds 110% at 28 days. The addition of the activator further improves the activity index of the ultra-fine nano-scale active admixture.

[0073] Performance Testing of Grouting Materials

[0074] For the testing of the fluidity and expansion rate of the grouting materials, refer to GB / T 50448-2015 "Technical Specification for Application of Cementitious Grouting Materials". The mold used for fluidity is a frustum cone mold with an upper inner diameter of 70 mm ± 0.5 mm, a lower inner diameter of 100 mm ± 0.5 mm, and a height of 60 mm ± 0.5 mm. The testing method for the mechanical properties in the grouting material test is carried out according to the provisions of GBT17671-2021 "Test Method for the Strength of Cement Mortar (IS0 Method)". The grouting material is poured into a test mold of 50 mm × 50 mm × 150 mm, and the molding should be completed within 10 minutes. After standard curing, the flexural and compressive strengths at 3 days, 7 days, and 28 days are measured. The electric flux and elastic modulus of the grouting material are determined according to the methods specified in the standard GB / T50082-2009 "Standard Test Method for Long-Term Performance and Durability of Ordinary Concrete".

[0075] The specific test results are recorded in Table 2.

[0076] Table 2

[0077]

[0078] In Example 2 and Comparative Example 5, the grouting materials have good fluidity, low viscosity of the mixture, small slump loss, and no bleeding phenomenon. By comparing Example 2 and Comparative Example 5, it is found that glass microspheres are beneficial to improving the fluidity, compressive strength, and chloride ion permeability resistance of the mixture, and the foaming agent can significantly inhibit the shrinkage of the mixture in the plastic stage.

[0079] It can be seen from Table 2 that when the dosage of marble powder and granite powder is appropriately increased, the strength of the high-strength anti-fatigue load steel-concrete connection grouting material prepared does not decrease significantly. When preparing the high-strength anti-fatigue load steel-concrete connection grouting material, reasonable incorporation of marble powder and granite powder can reduce the dosage of silica fume.

[0080] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art can make various modifications to the above content without departing from the spirit and scope of the present invention determined by the claims. Therefore, all equivalent technical solutions should also fall within the scope of the present invention.

Claims

1. A grouting material, characterized in that: the grouting material comprises the following components by mass percentage: 25% - 38% of cement, 5% - 14% of glass microspheres, 2 - 5% of silica fume, 5% - 20% of ultra-fine nano-scale active admixture, 2 - 5% of high-strength fiber, 0.1% - 1% of toughening fiber, 0.2% - 0.4% of polycarboxylate water reducer, 0% - 0.02% of defoamer, 0% - 0.04% of foaming agent, 28% - 42% of river sand, 12% - 18% of ground river sand; by weight, the ultra-fine nano-scale active admixture comprises 30 - 50 parts of slag, 20 - 50 parts of steel slag, 10 - 50 parts of fly ash, 1 - 10 parts of marble powder, 2 - 10 parts of granite powder, 2 - 8 parts of nano calcium carbonate, 2 - 8 parts of nano silicon dioxide, 1 - 10 parts of activator; The activator is composed of industrial gypsum and calcium bicarbonate in a weight ratio of 1:1; the marble powder and granite powder are waste powders generated during the cutting of marble and granite in a stone factory, and their specific surface areas are both greater than 680 m 2 / kg, and their average particle sizes are both less than 35 μm; the particle size of the nano calcium carbonate is 100-200 nm, and the particle size of the nano silicon dioxide is 100-150 nm; the preparation method of the ultra-fine nano-scale active admixture comprises the following steps: Step 1: According to the required parts by weight, add slag, fly ash, and steel slag into a ball mill for grinding; the ball milling time of the ball mill is 30 - 60 min to obtain industrial solid waste powder; Step 2: Add marble powder, granite powder, nano calcium carbonate, and nano silicon dioxide to the industrial solid waste powder obtained in Step 1, and continue to start the ball mill for grinding; the ball milling time of the ball mill is 20 - 40 min to obtain nano-modified industrial solid waste powder, that is, ultra-fine nano-scale active admixture; the preparation method of the grouting material comprises the following steps: (1) According to the mass percentage, take 25% - 38% of cement, 5% - 14% of glass microspheres, 2 - 5% of silica fume, 5% - 20% of ultra-fine nano-scale active admixture, 2 - 5% of high-strength fiber, 0.1% - 1% of toughening fiber, 0.2% - 0.4% of polycarboxylate water reducer, 0% - 0.02% of defoamer, 0% - 0.04% of foaming agent, 28% - 42% of river sand, 12% - 18% of ground river sand; (2) Grind natural river sand in a ball mill to an average particle size of 0.08 - 0.15 mm to obtain ground river sand; (3) Dry mix the river sand and ground river sand in a dry mixer according to the proportions weighed in step (1) for 5 min, and stop the machine; (4) Add the cement, glass microspheres, silica fume, ultra-fine nano-scale active admixture, high-strength fiber, and toughening fiber weighed in step (1) into the dry mixer and restart the machine, and continue to dry mix for 5 min, and stop the machine; (5) Then evenly sprinkle the polycarboxylate water reducer, defoamer, and foaming agent weighed in step (1) into the dry mixer while it is running, and continue to dry mix for 20 min to obtain the grouting material; (6) Pack the grouting material prepared in step (5) into an inner-lined packaging bag, seal it, and store it; The cement described is ordinary Portland cement with a strength grade not lower than 42.5; both the polycarboxylate water reducer and the defoamer are powders. The water reduction rate of the polycarboxylate water reducer is not less than 25%, and the defoamer is of the silicone type; the 28-day activity index of the silica fume is 100-106%, the SiO 2 content is not less than 95%, and the average particle size is 0.5-3 μm; the high-strength fiber is copper-plated microfilament steel fiber, with an average length of 4 - 8 mm, a diameter of 0.1 - 0.2 mm, and a tensile strength of not less than 2850 Mpa; the toughening fiber is glass fiber, with an average length of 50 - 100 μm and a diameter of 5 - 10 μm; The foaming agent is an amide organic powder that can decompose to produce nitrogen in an alkaline environment; the river sand is obtained by screening natural river sand with a moisture content of less than 0.1%, and the part with a particle size of 0.15 - 1.18 mm is taken; the ground river sand is obtained by grinding natural river sand, and the average particle size is 0.08 - 0.15 mm.

2. The grouting material according to claim 1, characterized in that: by weight, the ultra-fine nano-scale active admixture includes 40 - 50 parts of slag, 40 - 50 parts of steel slag, 20 - 50 parts of fly ash, 1 - 5 parts of marble powder, 2 - 5 parts of granite powder, 2 - 5 parts of nano calcium carbonate, 2 - 5 parts of nano silicon oxide, and 2 - 6 parts of activator.

3. The grouting material according to claim 1, characterized in that: by weight, the ultra-fine nano-scale active admixture includes 40 parts of slag, 40 parts of steel slag, 20 parts of fly ash, 3 parts of marble powder, 3 parts of granite powder, 6 parts of nano calcium carbonate, 6 parts of nano silicon oxide, and 5 parts of activator.

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