Early-strength and quick-hardening concrete repairing material with zero cement consumption

Abstract

The invention relates to an early-strength and quick-hardening concrete repairing material with zero cement consumption. The early-strength and quick-hardening concrete repairing material is prepared from steel slag powder, coarse aggregate, fine aggregate, carbide slag, sodium water glass and water in proportion. The repairing material has the characteristics of greenness, environmental protection, simple proportioning, easily available raw materials, simplicity and convenience in construction, quick setting and hardening, high compressive strength and the like. Meanwhile, the material is convenient to prepare and use, and can be widely applied to rapid repair of various projects such as roads, airport runways, bridges, ports and wharfs. The invention has the advantages of zero cement consumption, simple preparation and construction process and high compressive strength.

Description

[0001] Technical field: The present invention relates to the field of quick-setting concrete, and in particular to high-strength quick-setting concrete made from industrial waste and a preparation method thereof.

[0002] Background technology: The production process of cement in traditional concrete releases a large amount of carbon dioxide, causing serious carbon emission problems. Reducing cement consumption and finding alternative materials have become important goals in the current construction industry. In addition, with the acceleration of the industrialization process, a large amount of industrial solid waste has been generated. If these solid wastes can be effectively utilized, they can not only reduce environmental pollution but also save resources. Therefore, a zero-cement concrete repair material based on industrial solid waste is developed, which can meet the strength requirements while reducing the impact on the environment.

[0003] Invention content: The purpose of the present invention is to provide a method for preparing early-strength and fast-hardening concrete materials using industrial waste to solve the problems raised by the above materials.

[0004] In order to solve the above technical problems, the present invention provides the following technical solutions: steel slag powder, coarse aggregate, fine aggregate, and carbide slag are mixed evenly, and water glass with a certain modulus prepared in advance with sodium hydroxide and water are added and stirred evenly to obtain a quick-setting concrete material. The concrete reaches an initial setting state about 3-5 minutes after the end of stirring. Reaction mechanism: In the process of water glass (Na2SiO3) and sodium hydroxide (NaOH) jointly stimulating steel slag and carbide slag, a series of complex chemical reactions mainly occur. Water glass provides soluble silicate (SiO4 2 -), and NaOH increases the alkaline environment of the system, thereby promoting the reaction of the components in steel slag and carbide slag with the activator to generate a product with gelling properties.

[0005] 1. Reaction of carbide slag with water glass and NaOH

[0006] The main components of carbide slag are Ca(OH)2, CaO, CaCO3, and SiO2, among which Ca(OH)2 and CaO are the main active components.

[0007] Reaction of Ca(OH)2 (calcium hydroxide) with water glass and NaOH:

[0008] Ca(OH)2+Na2SiO3→CSH gel+2NaOH

[0009] In a high alkalinity environment, Ca(OH)2 reacts with Na2SiO3 to form calcium silicate hydrate (CSH gel), which is a strong gelling product.

[0010] CaCO3 (calcium carbonate) does not easily react in an alkaline environment, but partial dissolution and reprecipitation may occur.

[0011] SiO2 (silicon dioxide) dissolves under alkaline conditions to form silicate (SiO4 2- ), and Ca 2+ Reactions occur to generate more CSH gel:

[0012] SiO2+Ca(OH)2→CSH gel

[0013] 2. Reaction of steel slag with water glass and NaOH

[0014] The main components of steel slag include CaO, SiO2, Al2O3, and Fe2O3, among which CaO and SiO2 are the main active substances.

[0015] Reaction of CaO (calcium oxide) with water glass and NaOH:

[0016] CaO+Na2SiO3+H2O→CSH gel+2NaOH

[0017] Similar to carbide slag, CaO reacts with water glass to form CSH gel.

[0018] SiO2 (silicon dioxide) dissolves under the action of NaOH and reacts with Ca 2+ More CSH gel was generated.

[0019] Al2O3 (aluminum oxide) and Fe2O3 (iron oxide) react with Na in alkaline solution. + , Ca 2+ The plasma reacts to generate calcium aluminate hydrate (CAH gel) or calcium ferrite hydrate (CFH gel), further enhancing the gelling properties of the material.

[0020] Al2O3+Ca(OH)2+NaOH→CAH gel

[0021] Fe2O3+Ca(OH)2+NaOH→CFH gel

[0022] The above hydration products form the main component of the concrete matrix, thus giving the concrete strength and hardness.

[0023] Implementation method: 400-600 parts of steel slag, 3-30 parts of carbide slag, 500-800 parts of sand, 500-700 parts of fine aggregate, 500-700 parts of coarse aggregate, 100-200 parts of sodium water glass, and 40-70 parts of water, wherein the modulus of sodium water glass is between 1.6-2.4 and the alkali content is between 4%-7%.

[0024] Baseline group: 6.43 kg of steel slag, 8.29 kg of fine aggregate, 15.36 kg of coarse aggregate, 0.82 kg of water, and 2.3 kg of sodium water glass with a modulus of 1.8.

[0025] Example 1: 6.36 kg of steel slag, 0.064 kg of carbide slag, 8.29 kg of fine aggregate, 15.36 kg of coarse aggregate, 0.82 kg of water, and 2.3 kg of sodium water glass with a modulus of 1.8.

[0026] Example 2: 6.11 kg of steel slag, 0.257 kg of carbide slag, 8.29 kg of fine aggregate, 15.36 kg of coarse aggregate, 0.82 kg of water, and 2.3 kg of sodium water glass with a modulus of 1.8.

[0027] Description of the drawings: Figure 1 It is a concrete preparation process, and the specific steps are as follows: S1: weigh raw materials, including ① steel slag, ② coarse aggregate, ③ fine aggregate, ④ carbide slag, ⑤ water and ⑥ water glass solution.

[0028] S2: Pour the dry ingredients into the mixer one by one.

[0029] S3: Turn on the mixer and dry mix at a speed of 60r / min for 30s to mix the materials evenly to obtain a dry mix.

[0030] S4: Turn on the mixer, add water and sodium water glass solution, and stir at a speed of 60r / min for 2-3min.

[0031] S5: fresh concrete is obtained.

[0032] S6: Pour fresh concrete into the mold or the location to be repaired.

[0033] It can be seen from Table 1 that the early strength of concrete in Example 1 and Example 2 with the addition of carbide slag is further improved, and the compressive strength of concrete in Example 2 has reached 28.3MPa at 3h. The compressive strength of the three concretes at 28d is higher than 80MPa.

[0034] Table 1 Concrete compressive strength (MPa)

[0035] Age 1h 3h 7h 1d 3d 28d Benchmark Group 8.9 12.0 22.8 50.3 64.3 86.6 Example 1 9.0 19.1 39.6 55.2 73.8 81.7 Example 2 9.9 28.3 46.2 61.0 71.8 87.3

Claims

1. A zero-cement early-strength and fast-hardening concrete repair material, characterized by: It is made of steel slag powder, coarse aggregate, fine aggregate, carbide slag, sodium water glass and water in proportion. The material has zero cement consumption and its compressive strength can reach 80MPa after 28 days. Note: Cement production is a high-carbon emission industry. By developing the potential activity of industrial solid waste to meet the strength requirements of materials in engineering projects, reducing the amount of cement used can reduce carbon emissions in the construction industry.

2. A zero-cement early-strength and fast-hardening concrete repair material, characterized by: By adding industrial solid waste carbide slag into the material, the compressive strength of the material can reach 28MPa in 3 hours. Description: Calcium carbide slag is the industrial waste residue after acetylene gas is obtained by hydrolyzing calcium carbide. Adding it to this material not only reduces the stock of calcium carbide slag, but also improves the early compressive strength of the material, which is crucial for repair materials.

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