A kind of recycled glass fiber reinforced plastic powder-based low-carbon mortar and preparation method thereof

Abstract

The present invention provides a recycled glass fiber reinforced plastic powder-based low-carbon mortar and a preparation method thereof, and relates to the technical field of low-carbon mortar preparation. The recycled glass fiber reinforced plastic powder-based low-carbon mortar is prepared by mixing recycled glass fiber reinforced plastic powder, slag and aggregate, and then adding an alkali activator to make the alkali activator react with the recycled glass fiber reinforced plastic powder and slag to form a cementitious material; the recycled glass fiber reinforced plastic powder-based low-carbon mortar is made of the following raw materials in terms of mass percentage: 8-26% recycled glass fiber reinforced plastic powder, 8-26% slag, 18% alkali activator, and 48% aggregate. The recycled glass fiber reinforced plastic powder-based low-carbon mortar in the present invention can make full use of glass fiber reinforced plastic waste, and the 7d flexural strength of the obtained recycled glass fiber reinforced plastic powder-based low-carbon mortar is increased by 50% compared with the fly ash-based low-carbon mortar, which effectively improves the flexural strength of the mortar, while also reducing carbon emissions, and the 28d strength can reach more than 40Mpa.

Description

Technical Field

[0001] The invention relates to the technical field of low-carbon mortar preparation, and in particular to a recycled glass fiber reinforced plastic powder-based low-carbon mortar and a preparation method thereof. Background Art

[0002] Cement and its cementitious materials are widely used in major engineering fields such as infrastructure and house construction. However, the production of one ton of cement will produce about 0.8 to 0.9 tons of CO2, which not only consumes a large amount of resources, but also produces a large amount of greenhouse gases, which is not conducive to environmental protection.

[0003] In recent years, low-carbon cement-free cementitious materials such as geopolymers have attracted the attention of a large number of experts and scholars. Geopolymers refer to alkali-activated semi-crystalline aluminosilicates formed by the reaction of aluminosilicates in an alkaline medium, in which active aluminosilicates can become geopolymers through alkaline media. At present, the main geopolymers studied are industrial by-products such as fly ash and slag. The existing technology usually uses fly ash and slag under the action of an alkali activator to obtain a cementitious material. However, the mortar prepared using the cementitious material has the problem of poor flexural strength. In addition, with the gradual transformation of industries such as coal mining and thermal power generation, the sources of industrial by-products such as fly ash are gradually reduced. Therefore, it is necessary to find a cementitious material that can replace fly ash and improve the flexural strength of mortar.

[0004] FRP is widely used in infrastructure, wind power generation and other fields due to its light weight, high strength and good corrosion resistance. However, due to its short service life and the large amount of scraps generated during the manufacturing process, it has caused huge pressure on the society to deal with solid waste. The environmental pollution and waste of resources have caused serious environmental, social and economic problems. However, traditional treatment methods such as incineration or landfill have brought huge pollution to the environment.

[0005] Therefore, there is a need for a composite material that can recycle FRP and improve the flexural strength of mortar. Summary of the invention

[0006] In order to solve the problem that the mortar prepared by using alkaline cementitious materials obtained from fly ash and slag in the prior art has poor flexural properties, the present invention provides a recycled glass fiber reinforced plastic powder-based low-carbon mortar and a preparation method thereof.

[0007] The present invention obtains a cementitious material by mixing recycled FRP powder with slag and causing a condensation reaction under the action of an alkali activator. This can not only effectively improve the flexural strength of the mortar, but also solve the problem of recycling and reusing FRP waste, thus solving the problem of solid waste treatment caused by FRP recycling. Compared with cement-based materials, this material is greener and has a lower carbon content.

[0008] In order to achieve the above object, the technical solution of the present invention is as follows.

[0009] The first aspect of the present invention provides a recycled glass fiber reinforced plastic powder-based low-carbon mortar. The recycled glass fiber reinforced plastic powder-based low-carbon mortar is prepared by mixing recycled glass fiber reinforced plastic powder, slag and aggregate, and then adding an alkali activator to allow the alkali activator to react with the recycled glass fiber reinforced plastic powder and slag to form a cementitious material;

[0010] The recycled glass fiber reinforced plastic powder-based low-carbon mortar is made of the following raw materials, calculated by mass percentage: 8-26% recycled glass fiber reinforced plastic powder; 8-26% slag; 18% alkali activator; and 48% aggregate.

[0011] In another preferred embodiment, the preparation method of the regenerated fiberglass powder is as follows:

[0012] The fiberglass waste is crushed and sieved to obtain the regenerated fiberglass powder.

[0013] Among them, the main components of recycled FRP powder are silicon dioxide, aluminum oxide, magnesium oxide, calcium oxide, etc. It has certain volcanic ash activity and is a relatively high-quality aluminosilicate. By reacting with alkali activators, it can dissolve and polycondense to produce gels such as C-(A)-SH and N-(A)-SH, which can be used as a low-carbon cement-free cementitious material. In addition, recycled FRP powder can play a bridging role inside the mortar, thereby effectively hindering the production and expansion of cracks inside the mortar, thereby improving the flexural strength of the mortar.

[0014] In another preferred embodiment, the particle size ratio of the sieved recycled FRP powder is as follows:

[0015] The mass percentage of recycled FRP powder passing through the 100μm aperture sieve is ≥95%;

[0016] The mass percentage of recycled FRP powder passing through the 50μm aperture sieve is ≥75%;

[0017] The mass proportion of recycled FRP powder passing through the 1μm aperture sieve is ≥25%.

[0018] In another preferred embodiment, the alkaline activator is sodium hydroxide solution and sodium silicate solution.

[0019] In another preferred embodiment, the mass ratio of the sodium hydroxide solution to the sodium silicate solution is 6-9:9-12.

[0020] In another preferred embodiment, the concentration of the sodium hydroxide solution is 4-14 mol / L; this concentration can accelerate the depolymerization process of the crystal structure of substances such as SiO2, CaO, Al2O3, thereby accelerating the condensation reaction, shortening the generation time of gels such as C-(A)-SH, and further increasing the amount of gel generated, thereby improving the mortar strength.

[0021] The modulus of the sodium silicate solution is 3.3, the solid content is 35.5%, and the mass ratio of Na2O, SiO2 and H2O in the sodium silicate solution is 8.83:26.98:64.19.

[0022] In another preferred embodiment, the slag is 500-800 mesh slag; the slag is S95 slag powder, and the S95 slag powder meets the requirements of the specification "GB / T18046-2017".

[0023] In another preferred embodiment, the aggregate is 80-160 mesh aggregate, and the aggregate is quartz sand.

[0024] The second aspect of the present invention provides a method for preparing a recycled glass fiber reinforced plastic powder-based low-carbon mortar, wherein the recycled glass fiber reinforced plastic powder-based low-carbon mortar is the recycled glass fiber reinforced plastic powder-based low-carbon mortar provided by the first aspect of the present invention, comprising the following steps:

[0025] Weigh each raw material according to the mass percentage in the first aspect of the present invention;

[0026] The sodium hydroxide is prepared into a sodium hydroxide solution, and the sodium hydroxide solution is mixed with a sodium silicate solution to obtain an alkali activator;

[0027] The recycled FRP powder and slag powder are first dry-mixed for 2 to 3 minutes, and then mixed with aggregate for 2 to 3 minutes to obtain a mixture;

[0028] The alkali activator is mixed with the mixed material to obtain the recycled glass fiber reinforced plastic powder-based low-carbon mortar.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] (1) Compared with fly ash-based mortar, the 7d flexural strength of the recycled FRP powder low-carbon mortar prepared by the present invention is 53% higher and the 28d flexural strength is 18% higher, which effectively improves the flexural strength of the mortar. In addition, the cementitious material uses recycled FRP powder, which makes full use of FRP waste, greatly improves the recycling efficiency of FRP waste, reduces traditional FRP waste recycling methods, and realizes the resource utilization of FRP waste.

[0031] (2) The present invention uses recycled fiberglass powder and slag as the main cementitious materials, quartz sand as aggregate, and an alkali activator to prepare a low-carbon mortar, which has a 28d strength of more than 40Mpa and is a more green and low-carbon building material.

[0032] (3) The preparation process of the present invention is simple, has low cost, low carbon emissions, good performance, can effectively save resources and energy, and has extremely high economic and social benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a composition diagram of the recycled glass fiber reinforced plastic powder-based low-carbon mortar in Example 1 of the present invention.

[0034] Figure 2 This is a flow chart for preparing recycled fiberglass powder-based low-carbon mortar in Example 1 of the present invention.

[0035] Figure 3 This is a diagram of the recycled fiberglass powder in Example 1 of the present invention.

[0036] Figure 4 This is a maintenance diagram of the recycled fiberglass powder-based low-carbon mortar in Example 1 of the present invention.

[0037] Figure 5 This is a graph showing the compressive strength of the recycled glass fiber reinforced plastic powder-based low-carbon mortar as a function of curing time in Example 1 of the present invention. DETAILED DESCRIPTION

[0038] The specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings, but it should be understood that the protection scope of the present invention is not limited by the specific embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without creative work belong to the scope of protection of the present invention. The raw materials used in the present invention without indicating the manufacturer are all conventional products that can be purchased commercially.

[0039] In order to make the contents of the present invention easier to understand, the technical solution of the present invention is further described below in conjunction with specific implementation methods, but the present invention is not limited thereto.

[0040] The raw materials used in the following examples are recycled glass fiber reinforced plastic powder and the slag is S95 slag powder, and the main components thereof are shown in Table 1.

[0041] Table 1 Main components of recycled FRP powder and slag

[0042]

[0043] The recycled FRP powder described in the following examples is obtained by crushing and sieving retired FRP materials to obtain a powder with a particle size of >200 mesh.

[0044] The following is a detailed description of a recycled fiberglass powder-based low-carbon mortar.

[0045] Example 1

[0046] A recycled glass fiber reinforced plastic powder-based low-carbon mortar, wherein the recycled glass fiber reinforced plastic powder-based low-carbon mortar is prepared from the following raw materials in terms of mass percentage:

[0047] 17% recycled fiberglass powder; 17% slag; 48% quartz sand; 9% sodium silicate solution; 9% sodium hydroxide solution;

[0048] The modulus of the sodium silicate solution is 3.3 and the solid content is 35.5%;

[0049] The concentration of the sodium hydroxide solution is 8 mol / L.

[0050] The preparation method of the above-mentioned recycled glass fiber reinforced plastic powder-based low-carbon mortar is as follows: Figure 1-2 As shown, the following steps are included:

[0051] S1. Grind and sieve the FRP waste to a particle size of >200 mesh to obtain recycled FRP powder. The mass proportion of recycled FRP powder passing through a 100 μm sieve is ≥95%; the mass proportion of recycled FRP powder passing through a 50 μm sieve is ≥75%; the mass proportion of recycled FRP powder passing through a 1 μm sieve is ≥25%. Figure 3 As shown;

[0052] S2, mixing sodium hydroxide and water to prepare a sodium hydroxide solution with a concentration of 8 mol / L, and cooling to room temperature;

[0053] S3, slowly adding the sodium silicate solution into the sodium hydroxide solution and leaving it for 24 hours to obtain an alkaline activator;

[0054] S4, dry-mix the recycled glass fiber reinforced plastic powder and slag for 2 minutes, then add the quartz sand and dry-mix for 2 minutes to obtain a mixture;

[0055] S5. Add the alkali activator to the mixture and stir for 2 minutes;

[0056] S6. Put it into a mold, vibrate it and perform curing to obtain recycled FRP powder-based low-carbon mortar.

[0057] Example 2

[0058] A recycled glass fiber reinforced plastic powder-based low-carbon mortar, wherein the recycled glass fiber reinforced plastic powder-based low-carbon mortar is prepared from the following raw materials in terms of mass percentage:

[0059] 26% recycled glass fiber reinforced plastic powder; 8% slag; 48% quartz sand; 11% sodium silicate solution; 7% sodium hydroxide solution; the modulus of the sodium silicate solution is 3.3 and the solid content is 35.5%;

[0060] The concentration of the sodium hydroxide solution is 12 mol / L.

[0061] The method for preparing the above-mentioned recycled glass fiber reinforced plastic powder-based low-carbon mortar comprises the following steps:

[0062] S1. Grind and sieve the FRP waste to a particle size of >200 mesh to obtain recycled FRP powder, wherein the mass proportion of recycled FRP powder passing through a 100 μm aperture sieve is ≥95%; the mass proportion of recycled FRP powder passing through a 50 μm aperture sieve is ≥75%; the mass proportion of recycled FRP powder passing through a 1 μm aperture sieve is ≥25%.

[0063] S2, mixing sodium hydroxide and water to prepare a sodium hydroxide solution with a concentration of 12 mol / L, and cooling to room temperature;

[0064] S3, slowly adding the sodium silicate solution into the sodium hydroxide solution and leaving it for 24 hours to obtain an alkaline activator;

[0065] S4, dry-mix the recycled glass fiber reinforced plastic powder and slag for 2 minutes, then add the quartz sand and dry-mix for 2 minutes to obtain a mixture;

[0066] S5. Add the alkali activator to the mixture and stir for 2 minutes;

[0067] S6. Put it into a mold, vibrate it and perform curing to obtain recycled FRP powder-based low-carbon mortar.

[0068] Example 3

[0069] A recycled glass fiber reinforced plastic powder-based low-carbon mortar, wherein the recycled glass fiber reinforced plastic powder-based low-carbon mortar is prepared from the following raw materials in terms of mass percentage:

[0070] 14% recycled glass fiber reinforced plastic powder; 20% slag; 48% quartz sand; 12% sodium silicate solution; 6% sodium hydroxide solution; the modulus of the sodium silicate solution is 3.3 and the solid content is 35.5%;

[0071] The concentration of the sodium hydroxide solution is 10 mol / L.

[0072] The method for preparing the above-mentioned recycled glass fiber reinforced plastic powder-based low-carbon mortar comprises the following steps:

[0073] S1. Grind and sieve the FRP waste to a particle size of >200 mesh to obtain recycled FRP powder, wherein the mass proportion of recycled FRP powder passing through a 100 μm aperture sieve is ≥95%; the mass proportion of recycled FRP powder passing through a 50 μm aperture sieve is ≥75%; the mass proportion of recycled FRP powder passing through a 1 μm aperture sieve is ≥25%;

[0074] S2, mixing sodium hydroxide and water to prepare a sodium hydroxide solution with a concentration of 10 mol / L, and cooling to room temperature;

[0075] S3, slowly adding the sodium silicate solution into the sodium hydroxide solution and leaving it for 24 hours to obtain an alkaline activator;

[0076] S4, dry-mix the recycled glass fiber reinforced plastic powder and slag for 2 minutes, then add the quartz sand and dry-mix for 2 minutes to obtain a mixture;

[0077] S5. Add the alkali activator to the mixture and stir for 2 minutes;

[0078] S6. Put it into a mold, vibrate it and perform curing to obtain recycled FRP powder-based low-carbon mortar.

[0079] Example 4

[0080] A recycled glass fiber reinforced plastic powder-based low-carbon mortar, wherein the recycled glass fiber reinforced plastic powder-based low-carbon mortar is prepared from the following raw materials in terms of mass percentage:

[0081] 8% recycled fiberglass powder, 26% slag, 48% quartz sand, 9% sodium silicate solution, 9% sodium hydroxide;

[0082] The modulus of the sodium silicate solution is 3.3 and the solid content is 35.5%;

[0083] The concentration of the sodium hydroxide solution is 8 mol / L.

[0084] The method for preparing the above-mentioned recycled glass fiber reinforced plastic powder-based low-carbon mortar comprises the following steps:

[0085] S1. Grind and sieve the FRP waste to a particle size of >200 mesh for standby use to obtain recycled FRP powder; the mass proportion of recycled FRP powder passing through a 100 μm aperture sieve is ≥95%; the mass proportion of recycled FRP powder passing through a 50 μm aperture sieve is ≥75%; the mass proportion of recycled FRP powder passing through a 1 μm aperture sieve is ≥25%;

[0086] S2, mixing sodium hydroxide and water to prepare a sodium hydroxide solution with a concentration of 8 mol / L, and cooling to room temperature;

[0087] S3, slowly adding the sodium silicate solution into the sodium hydroxide solution and leaving it for 24 hours to obtain an alkaline activator;

[0088] S4, dry-mix the recycled glass fiber reinforced plastic powder and slag for 4 minutes, then add the quartz sand and dry-mix for 4 minutes to obtain a mixture;

[0089] S5, adding the alkali activator to the mixture and stirring for 4 minutes;

[0090] S6, put into the mold, vibrate and cure, and obtain recycled glass fiber reinforced plastic powder-based low-carbon mortar, such as Figure 4 shown.

[0091] Comparative Example 1

[0092] A fly ash-based low-carbon mortar, wherein the fly ash-based low-carbon mortar is prepared from the following raw materials in terms of mass percentage:

[0093] 8% fly ash, 26% slag, 48% quartz sand, 9% sodium silicate solution, 9% sodium hydroxide solution;

[0094] The modulus of the sodium silicate solution is 3.3 and the solid content is 35.5%;

[0095] The concentration of the sodium hydroxide solution is 8 mol / L.

[0096] The preparation method of the fly ash-based low-carbon mortar comprises the following steps:

[0097] S1, prepare a sodium hydroxide solution with a concentration of 8 mol / L, and cool it to room temperature;

[0098] S3, slowly adding the sodium silicate solution into the sodium hydroxide solution and leaving it for 24 hours to obtain an alkaline activator;

[0099] S4, dry-mix the fly ash and slag for 4 minutes, then add the quartz sand and dry-mix for 4 minutes to obtain a mixture;

[0100] S5, adding the alkali activator to the mixture and stirring for 4 minutes;

[0101] S6. Put it into a mold, vibrate it and perform curing to obtain fly ash low-carbon mortar.

[0102] In order to further illustrate the performance of the recycled FRP powder-based low-carbon mortar in the present invention, we conducted the following experiments.

[0103] 1) The recycled FRP powder-based low-carbon mortar in Example 4 and the fly ash-based mortar in Comparative Example 1 were tested for compressive and flexural strength, respectively. The results are shown in Table 2.

[0104] Table 27d, 28d compressive and flexural strength test results

[0105]

[0106] As shown in Table 2, in terms of compressive strength, the compressive strength of the fly ash-based low-carbon mortar in Example 4 is comparable to that in Comparative Example 1, indicating that a mortar with high compressive strength can also be obtained by replacing fly ash with recycled FRP powder.

[0107] From the perspective of flexural strength, the 7d flexural strength of the recycled FRP powder-based low-carbon mortar in Example 4 is 50% higher than that of the fly ash-based low-carbon mortar in Comparative Example 1, and the 28d flexural strength is 18% higher than that of the fly ash-based low-carbon mortar in Comparative Example 1. It can be seen that the recycled FRP powder-based low-carbon mortar in the present invention improves the flexural strength of the mortar much higher than that of the fly ash-based low-carbon mortar in the early stage, and the flexural strength can still be maintained at a stable level until 28d, indicating that the flexural strength of the recycled FRP powder-based low-carbon mortar in the present invention is better than that of the fly ash-based mortar. This is mainly because the recycled FRP powder is fibrous on a microscopic scale, plays a bridging role inside the mortar, and can hinder the generation and expansion of cracks inside the mortar, thereby improving the flexural strength of the mortar.

[0108] 2) The recycled glass fiber reinforced plastic powder-based low-carbon mortar obtained in Examples 1 to 4 was subjected to test blocks, curing, demoulding, and testing in accordance with the standard GB / T17671-2021 "Test Method for Cement Mortar Strength (ISO Method)". The compressive strength test results at each age are shown in Table 3. Figure 5 This is a graph showing the compressive strength of the recycled FRP powder-based low-carbon mortar in Example 1 as a function of curing time.

[0109] Table 3 Compressive strength test results at different ages

[0110]

[0111]

[0112] It can be seen from Table 3 that the recycled FRP powder-based low-carbon mortars prepared in Examples 1 to 4 above all have good compressive strength.

[0113] It can be seen from Example 1 and Example 2 that with the increase in the amount of recycled FRP powder and the higher concentration of sodium hydroxide solution, the regenerated FRP powder-based low-carbon mortar with relatively ideal mechanical properties can be obtained by excitation. This shows that the sodium hydroxide solution with a concentration of 12 mol / L can promote the polycondensation reaction of the regenerated FRP powder in the present invention, which is beneficial to the formation of gels such as C-(A)-SH and N-(A)-SH in the mortar, so that the regenerated FRP powder-based low-carbon mortar has better mechanical properties, thereby improving the amount and utilization rate of the regenerated FRP powder.

[0114] As can be seen from Example 3, increasing the slag content and a higher concentration of alkali activator can prepare a high-strength recycled FRP powder-based low-carbon mortar. The reason is that the slag has a high content of active particles, and under the action of the alkali activator, it can quickly generate gel to improve the mortar strength. At the same time, a higher concentration of alkali activator can accelerate the depolymerization process of the crystal structure of substances such as SiO2, CaO, Al2O3, thereby accelerating the polycondensation reaction, shortening the generation time of gels such as C-(A)-SH, and further increasing the amount of gel generated, thereby improving the mortar strength. As can be seen from Examples 3 and 4, with the increase in the slag content, the recycled FRP powder-based low-carbon mortar has a fast compressive strength growth rate in the early stage, but a slower rate of strength increase in the later stage. The main reason is that the volcanic ash activity of the slag is high, and it can react quickly to generate CSH gel under the action of the alkali activator, so the early strength increases rapidly; when the highly active particles react quickly, the growth rate of the later strength is relatively slow.

[0115] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A recycled glass fiber reinforced plastic powder-based low-carbon mortar, characterized in that: The recycled FRP powder-based low-carbon mortar is made by mixing recycled FRP powder, slag and aggregate, using the recycled FRP powder to play a bridging role inside to prevent cracks from being generated and expanded; then adding an alkali activator to make the alkali activator react with the recycled FRP powder and slag to form a gelling material; The recycled glass fiber reinforced plastic powder-based low-carbon mortar is made of the following raw materials, calculated by mass percentage: 14% recycled glass fiber reinforced plastic powder, 20% slag, 18% alkali activator, 48% quartz sand, a total of 100%; The preparation method of the regenerated glass fiber reinforced plastic powder is as follows: The FRP waste is crushed and sieved to obtain the regenerated FRP powder; The particle size ratio of the sieved recycled FRP powder is as follows: The mass proportion of recycled FRP powder passing through the 100μm aperture sieve is ≥95%; The mass proportion of recycled FRP powder passing through the 50μm aperture sieve is ≥75%; The mass proportion of recycled FRP powder passing through the 1μm aperture sieve is ≥25%; The alkaline activator is sodium hydroxide solution and sodium silicate solution; the mass ratio of the sodium hydroxide solution to the sodium silicate solution is 6:12, and the concentration of the sodium hydroxide solution is 10 mol / L; the modulus of the sodium silicate solution is 3.3; the slag is S95 slag powder; and the particle size of the quartz sand is 80-160 mesh.

2. A method for preparing recycled glass fiber reinforced plastic powder-based low-carbon mortar, characterized in that: The following steps are involved: Weigh each raw material according to the mass percentage in claim 1; mixing a sodium hydroxide solution with a sodium silicate solution to obtain an alkaline activator; The recycled glass fiber reinforced plastic powder and S95 slag powder are first dry-mixed, and then dry-mixed with quartz sand to obtain a mixture; The alkali activator is mixed with the mixed material to obtain the recycled glass fiber reinforced plastic powder-based low-carbon mortar.

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