High water stability granite stone powder based road base material and preparation method

Abstract

The application discloses a kind of high water stability granite stone powder-based road base materials, composition is as follows according to weight fraction: waste granite stone powder 100 parts;Cement 3-8 parts;Multifunctional water stabilizer 0.5-1 parts;Water 10-19 parts;The preparation method of the multifunctional water stabilizer includes the following steps: preparation of acrylic monomer mixed solution, under stirring dropwise add the aqueous solution of nanosol, stirring mixes 20-40 minutes;Heating to 80-90 ℃ ammonium persulfate aqueous solution is added, and reaction is 1-2 hours, and multifunctional water stabilizer is obtained;The present application uses multifunctional water stabilizer to make up for the deficiency of granite stone powder road base material, not only can improve granite stone powder consumption, while significantly improving the water stability of road base material on the basis of meeting engineering index requirements.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of building materials, and particularly relates to a high-water-stability granite stone powder-based road base material and a preparation method thereof. BACKGROUND

[0002] Granite is widely used as a decoration material for buildings due to its hard texture and high strength. However, a large amount of granite stone powder is generated during the processing of granite. The accumulation of granite stone powder not only occupies a large area of land resources, but also easily forms dust, pollutes the environment, and affects air quality. At present, some researches on the resource utilization of granite stone powder involve mixing granite stone powder with other solid wastes to prepare cementitious materials. For example, patent CN113620618A discloses a method for preparing an integrated cementitious material using granite stone powder and coal combustion residues. However, the disclosed method in the patent application has a complex process and requires high-temperature calcination in an oxygen atmosphere. Moreover, the amount of granite stone powder used is not high, which cannot achieve efficient and low-carbon utilization of granite stone powder.

[0003] It is considered that the preparation of road base materials from solid waste is an effective way to dispose of a large amount of solid waste. For example, patent CN115231886A discloses a method for preparing a solid waste-based road base material using thermal desorption product soil and iron tailings waste rock. The aggregate used in the prepared road base material is composed of thermal desorption product soil and iron tailings waste rock. However, this patent only considers the mechanical properties of the material and does not consider other properties. The water stability performance is a measure of the ability of road base materials to resist rainwater erosion. The commonly used stabilizing material in road base materials is hydraulicity. Due to the small amount of stabilizing material used in road base materials, the colloid produced by the stabilizing material when it comes into contact with water cannot form a cross-linked whole stable aggregate, which leads to the formation of a large number of unstable spaces inside the road base material. These spaces are prone to cracking under the erosion of external rainwater or long-term immersion, which seriously affects the water stability performance of the material.

[0004] At present, there are few studies on the preparation of road base materials using only granite stone powder as aggregate, but there are many studies on the preparation of road base materials using other industrial waste residues. The research mainly focuses on the following aspects:

[0005] (1) Designing the gradation of solid waste aggregate. Patent 202310614253.7 uses industrial solid waste titanium slag as aggregate, and through corresponding gradation design method and related performance test, the optimal titanium slag coarse and fine aggregate gradation is obtained, which enhances the skeleton density of the aggregate and improves the stability of the road base material. However, since the particle size of granite stone powder is single, it is not possible to improve the skeleton density of the aggregate by designing the gradation.

[0006] (2) Add modified fibers. Patents 202310680901.9 and 202310391627.3 add modified polypropylene fibers or BSⅡ basalt fibers to road base materials doped with stone chips or phosphogypsum, respectively, to optimize the crack resistance of the road base material. However, in the method disclosed in the patent, the fiber modification process is complex, and BSⅡ basalt fibers even undergo low-temperature plasma surface treatment, resulting in a complex preparation process of the road base material and high production cost.

[0007] (3) Add various admixtures. Patent 202310359557.3 uses iron tailings to prepare road base materials, and by adding betaine-type amphoteric high molecular surfactant and alkyl quaternary ammonium salt cationic surfactant, the stability of the material is improved, but these two types of surfactants only improve the lipophilicity of the iron tailings particle surface and reduce the negative charge, and the bonding force between the aggregates is mainly provided by the cement, so the function of the admixture is single. Patent 202310881797.X adds ion curing agent, early strength agent and anti-hard water agent during the preparation of red mud-graphite tailings road base material, and the three admixtures can simultaneously provide the ability to infiltrate the surface of solid waste particles and enhance particle agglomeration when used together. However, in the preparation method, due to the use of a large number of raw materials, only when the raw materials are added in a specific order can the overall strength of the material be significantly improved, so the preparation process of the road base material is complex.

[0008] In summary, when only granite stone powder is used as aggregate to prepare road base material, the water stability of the road base material is poor, and since the gradation cannot be designed, the performance of the road base material cannot be optimized by improving the skeleton density. In addition, the currently disclosed admixtures have the problems of single function or complex preparation process of road base material, and cannot meet the requirements of rapid mass production in actual application. How to consume a large amount of granite stone powder for road base material while ensuring its water stability has become a technical problem to be solved. SUMMARY

[0009] The present application aims to provide a granite stone powder-based road base material and a multifunctional water stabilizer, which can compensate for the shortcomings of the granite stone powder-based road base material, improve the consumption of granite stone powder, and significantly improve the water stability of the road base material while meeting the engineering index requirements.

[0010] To achieve the above-mentioned purposes, the technical solutions are as follows:

[0011] The high-water-stability granite stone powder-based road base material is composed of the following components in parts by weight:

[0012] Waste granite stone powder 100 parts; cement 3-8 parts; multifunctional water stabilizer 0.5-1 part; water 10-19 parts.

[0013] According to the above scheme, the preparation method of the multifunctional water stabilizer comprises the following steps:

[0014] A mixed solution of acrylic monomers is prepared, and the aqueous solution of nanosol is added dropwise under stirring, and stirred and mixed for 20-40 minutes;

[0015] The temperature is raised to 80-90℃, and an aqueous solution of ammonium persulfate is added, and reacted for 1-2 hours to obtain the multifunctional water stabilizer.

[0016] According to the above scheme, the acrylic monomers are as follows in terms of weight parts: methyl methacrylate 5-7 parts, butyl acrylate 26-28 parts, glycidyl methacrylate 0.5-0.9 parts, and acrylic acid 0.1-0.5 parts.

[0017] According to the above scheme, the nanosol is one or a mixture of two of nanosilica sol and nanoalumina sol, with a particle size of 10-35 nm; and the amount is 30%-40% of the total mass of the acrylic monomers.

[0018] According to the above scheme, the amount of ammonium persulfate is 0.5%-2% of the total mass of the acrylic monomers.

[0019] According to the above scheme, the maximum nominal particle size of the waste granite stone powder is not greater than 4.75 mm, and the water content is not greater than 13%.

[0020] According to the above scheme, the cement is ordinary portland cement, with a specification of P·O32.5 and above.

[0021] According to the above scheme, the water content of the road base material is 14%-19%, preferably 15%-17%.

[0022] The preparation method of the above high-water-stability granite stone powder-based road base material comprises the following steps:

[0023] The granite stone powder and water are stirred and mixed uniformly, and then sealed and allowed to stand for 2-3 hours;

[0024] The cement and multifunctional water stabilizer are added to the standing material and stirred uniformly;

[0025] The obtained mixture is compacted and formed to obtain the granite stone powder-based road base material.

[0026] According to the above scheme, the compaction degree is 90%-95%, preferably 92%-94%.

[0027] In the preparation process of the multifunctional water stabilizer, the nano silicon / aluminum sol is mixed with various esters, and the two solvents can be closely and uniformly combined by using the adsorption of the nano silicon / aluminum sol. The above mixed solution occurs the following three reactions under heating and the excitation of ammonium sulfate:

[0028] (1) The various esters occur polymerization reaction, various groups are connected with each other, and a network structure with hydrophobic function is formed;

[0029] (2) The nano silicon / aluminum sol occurs polycondensation reaction in an alkaline environment, and a-Si-Al-long chain with gelation effect is generated;

[0030] (3) Since the nano silicon / aluminum sol is in a closely combined state with various esters, in the process of the re-polymerization of various groups and silicon / aluminum depolymerization, the network structure with hydrophobic function and the-Si-Al-long chain with gelation effect occur nesting reaction, and on the basis of the-Si-Al-long chain, the network structure is linked through chemical bonding, and a network structure with gelation long chain structure is generated.

[0031] Compared with the prior art, the present application has the following advantages:

[0032] (1) The water stabilizer prepared by the present application contains various chemical structures and has multiple functions. When the water stabilizer contacts with stone powder particles, the water stabilizer is closely linked with the stone powder solid particles through the-Si-Al-gelation long chain formed by the sol, and a hydrophobic film that will not fall off is formed on the surface of the stone powder particles by combining the hydrophobic network structure formed by various esters. In addition, the-Si-Al-long chain contained in the hydrophobic film can also react with calcium hydroxide generated by cement hydration to generate calcium silicate hydrate gel, and the gel is nested with the hydrophobic network structure through the-Si-Al-long chain, thereby generating a new gelation hydrophobic film on the surface of the stone powder particles, further improving the bonding strength between the stone powder particles, effectively reducing the impact force of water flow on the weak connection of the stone powder particles, ensuring the stability of the material structure, and thereby improving the water stability of the road base material. After the prepared road base material is continuously immersed in water for 15 days, the mass loss rate is only 1.99%, and the unconfined compressive strength is only reduced by 4.88%.

[0033] (2) A new solid waste-based road base material is prepared by using the waste granite stone powder naturally stacked in a stone factory as a raw material, and the content of the original granite stone powder in the road base material is greater than 94%. Based on the effect of the multifunctional water stabilizer, the 7d unconfined compressive strength of the road base material can exceed 4MPa according to the test method of JTG E51-2009 "Test Code for Highway Engineering Inorganic Stabilized Material", under the condition that the cement content is only 4%-6% and the material preparation method is simple. It is proved that the road base material prepared by the present application has high water stability and high strength, which ensures the actual road performance of the material. DETAILED DESCRIPTION

[0034] The following examples further illustrate the technical solutions of the present application, but are not intended to limit the scope of protection of the present application.

[0035] Example 1

[0036] Preparation of multifunctional water stabilizer A: 12 parts of nano-silica sol was dispersed into 39 parts of water, then added dropwise into a mixed solution formed by 5 parts of methyl methacrylate, 28 parts of butyl acrylate, 0.5 parts of glycidyl methacrylate and 0.5 parts of acrylic acid under the stirring speed of 250 rpm, after mixing uniformly, a mixed solution formed by 0.3 parts of ammonium persulfate and 17.7 parts of water was added under the condition of water bath heating at 80℃, the stirring was stopped after 1 hour, and the liquid was cooled to room temperature to obtain multifunctional water stabilizer A.

[0037] Example 2

[0038] Preparation of multifunctional water stabilizer B: 12 parts of nano-aluminum sol was dispersed into 31 parts of water, then added dropwise into a mixed solution formed by 7 parts of methyl methacrylate, 26 parts of butyl acrylate, 0.9 parts of glycidyl methacrylate and 0.1 parts of acrylic acid under the stirring speed of 300 rpm, after mixing uniformly, a mixed solution formed by 0.6 parts of ammonium persulfate and 17.4 parts of water was added under the condition of water bath heating at 85℃, the stirring was stopped after 1.5 hours, and the liquid was cooled to room temperature to obtain multifunctional water stabilizer B.

[0039] Example 3

[0040] Preparation of multifunctional water stabilizer C: 12 parts of nano-sol (mass ratio of nano-silica sol and nano-aluminum sol was 5:5) was dispersed into 33 parts of water, then added dropwise into a mixed solution formed by 6 parts of methyl methacrylate, 27 parts of butyl acrylate, 0.7 parts of glycidyl methacrylate and 0.3 parts of acrylic acid under the stirring speed of 400 rpm, after mixing uniformly, a mixed solution formed by 0.45 parts of ammonium persulfate and 17.55 parts of water was added under the condition of water bath heating at 90℃, the stirring was stopped after 2 hours, and the liquid was cooled to room temperature to obtain multifunctional water stabilizer C.

[0041] Example 4

[0042] The material mixing ratio of Example 4 is shown in Table 1, and as a reference sample, no multifunctional water stabilizer is added in this example. The material preparation process is as follows: according to the water content, calculate the required amount of water, mix a certain amount of granite stone powder and water, then seal and soak for 2.5 hours. After the soaking is completed, a certain amount of cement and multifunctional water stabilizer are added to the soaking material and stirred uniformly. After stirring is completed, the above mixture is filled into a specific mold and compacted to form a granite stone powder-based road base material, and performance tests are conducted, wherein the cement is P·O42.5 ordinary portland cement.

[0043] Example 5

[0044] The material mixing ratio of Example 5 is shown in Table 1, and the difference between Example 5 and Example 4 is that:

[0045] 0.7 parts of multifunctional water stabilizer A is added in the mixing ratio, the water content is reduced to 16%, and the compactness is changed to 92%. The material preparation process is the same as that of Example 4.

[0046] Example 6

[0047] The material mixing ratio of Example 6 is shown in Table 1, and the difference between Example 6 and Example 4 is that:

[0048] In the mixing ratio, the amount of cement is increased to 6 parts, and 0.5 parts of multifunctional water stabilizer A is added.

[0049] The material preparation process is the same as that of Example 4.

[0050] Example 7

[0051] The material mixing ratio of Example 7 is shown in Table 1, and the difference between Example 7 and Example 4 is that:

[0052] 0.7 parts of multifunctional water stabilizer B is added in the mixing ratio, the water content is reduced to 16%, and the compactness is changed to 92%. The material preparation process is the same as that of Example 4.

[0053] Example 8

[0054] The material mixing ratio of Example 8 is shown in Table 1, and the difference between Example 8 and Example 4 is that:

[0055] In the mixing ratio, the amount of cement is increased to 6 parts, and 0.05 parts of multifunctional water stabilizer B is added.

[0056] The material preparation process is the same as that of Example 4.

[0057] Example 9

[0058] The material mixing ratio of Example 9 is shown in Table 1, and the difference between Example 9 and Example 4 is that:

[0059] The mixing ratio is added with 0.7 parts of multifunctional water stabilizer C, the water content is reduced to 16%, and the compaction degree is changed to 92%. The material preparation process is the same as example 4.

[0060] Example 10

[0061] The material mixing ratio of example 10 is shown in table 1, and the difference between example 10 and example 4 is that:

[0062] In the mixing ratio, the cement addition is increased to 6 parts, and 0.5 parts of multifunctional water stabilizer C is added.

[0063] The material preparation process is the same as example 4.

[0064] Comparative example 1

[0065] The difference between comparative example 1 and example 3 is that the multifunctional water stabilizer D prepared is not added with nano sol.

[0066] Comparative example 2

[0067] The difference between comparative example 2 and example 3 is that the multifunctional water stabilizer E prepared is not added with acrylic monomer.

[0068] Comparative example 3

[0069] The material mixing ratio of comparative example 3 is shown in table 1, and the difference between comparative example 3 and example 10 is that the multifunctional water stabilizer added is multifunctional water stabilizer D prepared in comparative example 1.

[0070] Comparative example 4

[0071] The material mixing ratio of comparative example 4 is shown in table 1, and the difference between comparative example 4 and example 10 is that the multifunctional water stabilizer added is multifunctional water stabilizer E prepared in comparative example 2.

[0072] Table 1 mixing ratio of granite stone powder based road base material

[0073]

[0074] According to the relevant specifications and test procedures in JTG E51-2009 "Highway Engineering Inorganic Binder Stabilized Material Test Procedures" standard, the mechanical properties of the above examples are detected, and the main detected properties include: 7d unconfined compressive strength and splitting tensile strength, and the results are shown in table 2.

[0075] Table 2 test results of mechanical properties of road base material

[0076]

[0077] From the results of Table 2, the 7d unconfined compressive strength of the granite stone powder-based road base material all reaches 4.0 MPa or above, meeting the use requirements of heavy traffic of expressway and first-class highway and extremely heavy traffic of second-class and below highways. The 7d unconfined compressive strength of the sample added with the multifunctional water stabilizer is higher than that of Example 4, proving that the nested cementitious structure generated by multiple structures can improve the mechanical properties of the material. Comparing Example 5 and 6, Example 7 and 8, and Example 9 and 10, it can be seen that appropriately increasing the cement dosage can improve the strength of the material, but the improvement effect is not obvious, and the reason is that the addition amount of the multifunctional water stabilizer in the mix proportion of Example 5, 7 and 8 is large. This result further proves that the multifunctional water stabilizer has the effect of improving the mechanical properties of the material, and appropriately increasing the addition amount of the multifunctional water stabilizer in the material mix proportion design helps to reduce the cement dosage, improve the environmental and social benefits of the granite stone powder-based road base material. In addition, comparing Example 4 and 10 with Comparative Example 3 and 4, it can be seen that the unconfined compressive strength of Comparative Example 3 is significantly reduced and is only higher than that of Example 4, and the unconfined compressive strength of Comparative Example 4 is also low. This result proves that the binding effect of the multifunctional water stabilizer and the unconfined compressive strength of the material are the result of the synergistic effect of nano sol, acrylic monomer and cement, and the absence of any of the three cannot achieve the best effect.

[0078] In addition to the conventional mechanical properties, whether the granite stone powder-based road base material can maintain the mechanical properties in water is a key problem of road performance, and therefore, the water stability of the granite stone powder-based road base material needs to be studied. The water stability of the material is reflected by detecting the strength and mass changes of the material after immersion in water, and the specific test method is as follows:

[0079] Immersion strength: first, the test piece is cured in a standard curing box for 7d, then immersed in water for 3d, 6d, 9d, 12d and 15d respectively, and then the compressive strength of the test piece at each immersion time is measured.

[0080] Immersion mass loss rate: first, the test piece is cured in a standard curing box for 7d, the mass of the test piece is measured and recorded as m0, then the test piece is immersed in water for 3d, 6d, 9d, 12d and 15d respectively, the mass of the test piece at each immersion time is measured and recorded as m1, and the immersion mass loss rate (w) is calculated according to the following formula.

[0081]

[0082] The test results are shown in Table 3.

[0083] Table 3 Test results of water stability of road base material

[0084]

[0085]

[0086] From the test results, the water immersion strength of Example 4 is reduced by 54% at the maximum, the water immersion mass loss rate is 5.7% at the maximum, after 15 days of water immersion, the test block becomes soft, and there is obvious cracking phenomenon on the surface. The water immersion strength of the sample added with the multifunctional water stabilizer gradually decreases with the water soaking time, and the water immersion mass loss rate also gradually increases, but the strength decrease value and the mass loss rate are obviously lower than those of Example 4. Taking Example 5 as an example, the 15d water immersion strength still remains at 94% of the initial strength, and the mass loss rate is only 2.32%. The comparison results of Comparative Examples 3 and 4 and Example 10 show that after the nanosol and the acrylic monomer are missing in the multifunctional water stabilizer, the compressive strength of the material after water immersion is significantly reduced, and the mass loss rate is obviously increased, which further proves that the nanosol, the acrylic monomer and the cement indeed have a synergistic effect. The above test results prove that the multifunctional water stabilizer provided by the present application can effectively improve the water immersion strength of the roadbed material, so that the prepared granite stone roadbed material has very high water stability. The roadbed material provided by the present application can save natural sand and stone, improve the utilization rate of waste granite stone powder, greatly reduce the raw material cost of the engineering project, and produce great environmental, social and economic benefits.

[0087] The above examples describe the basic principles, main features and advantages of the present application. The present application is not limited by the above examples, and the above examples and the description in the specification only illustrate the principles of the present application. Without departing from the scope of the principles of the present application, various changes and improvements can be made to the present application, which are all within the scope of the claims of the present application and are protected by the patent law.

Claims

1. A high water stability granite stone powder based road base material, characterized in that The components are as follows in parts by weight: 100 parts of waste granite stone powder, 3-8 parts of cement, 0.5-1 part of multifunctional water stabilizer, and 10-19 parts of water; The maximum nominal particle size of the waste granite stone powder is not greater than 4.75 mm, and the water content is not greater than 13%; The preparation method of the multifunctional water stabilizer comprises the following steps: A mixed solution of acrylic monomers is prepared, and a water solution of nano sol is added dropwise under stirring, and stirring is carried out for 20-40 minutes; the acrylic monomers are as follows in parts by weight: 5-7 parts of methyl methacrylate, 26-28 parts of butyl acrylate, 0.5-0.9 parts of glycidyl methacrylate, and 0.1-0.5 parts of acrylic acid; the nano sol is one of nano silicon sol and nano aluminum sol or a mixture of both, and the particle size is 10-35 nm; the amount is 30%-40% of the total mass of the acrylic monomers; The temperature is raised to 80-90℃, and an aqueous solution of ammonium persulfate is added, and the reaction is carried out for 1-2 hours to obtain the multifunctional water stabilizer.

2. The high water stable granite stone dust based road base material as claimed in claim 1 wherein The amount of ammonium persulfate is 0.5%-2% of the total mass of the acrylic monomers.

3. The high water stable granite stone dust based road base material as claimed in claim 1 wherein The cement is ordinary Portland cement, and the specification is P·O32.5 and above.

4. The high water stable granite stone dust based road base material as claimed in claim 1 wherein The water content of the road base material is 14%-19%.

5. The method of producing a high water stability granite stone powder based road base material as claimed in claim 1, wherein The method comprises the following steps: The granite stone powder and water are stirred and mixed uniformly, and then sealed and allowed to stand for 2-3 hours; The cement and multifunctional water stabilizer are added to the standing material and stirred uniformly; The obtained mixture is compacted to form the granite stone powder-based road base material.

6. The method of preparing high water stable granite stone powder based road base material as claimed in claim 5, wherein the granite stone powder is prepared by the process comprising of: The compaction degree is 90%-95%.

Images