Water-stabilized weathered materials for highway subgrade construction, their preparation methods and applications

Abstract

This invention relates to the field of road construction technology, specifically disclosing a water-stabilized weathered material for highway subgrade construction, its preparation method, and its application. The water-stabilized weathered material for highway subgrade construction comprises the following components in parts by weight: 100-120 parts water; 50-60 parts cement; 1000 parts weathered material; 10-12 parts compound bacterial solution; and 10-12 parts urea. The preparation method of the compound bacterial solution is as follows: Step 1), mix water, yeast powder, peptone, beef extract, sodium chloride, manganese sulfate, and urea to obtain a liquid culture medium; Step 2), add *Bacillus pasteurellii*, *Alkalophilus halophilus*, and *Narcissus alkali-resistant* to the liquid culture medium and culture until the OD value reaches 1-1.2 to obtain the compound bacterial solution. This invention has the advantage of further improving the strength of water-stabilized weathered materials.

Description

Technical Field

[0001] This invention relates to the field of road construction, and in particular to a water-stabilized weathered material for highway subgrade construction, its preparation method, and its application. Background Technology

[0002] The subgrade is the basic structure used to support the road surface. For road engineering projects like highways, which have high load-bearing requirements, the structural strength requirements of the subgrade are also high. Subgrades prepared by ordinary methods of compacting soil and filling materials are difficult to meet the needs of highways.

[0003] Existing highway subgrades are constructed using water-stabilized weathered aggregates, which mainly consist of cement and weathered aggregates. Due to the low cost of weathered aggregates, this is a mainstream construction method. However, existing water-stabilized weathered aggregates contain relatively little cement, resulting in only moderate bonding effectiveness. Although compaction can effectively reduce the porosity of the water-stabilized weathered aggregates, their strength remains low. Increasing the amount of cement would significantly increase costs. For the increasingly developed highway transportation system, further improving the load-bearing capacity of highways is an inevitable direction. However, existing water-stabilized weathered aggregates are difficult to improve in strength while controlling cost budgets, making it difficult to meet the needs of highway projects with higher load-bearing capacities. Therefore, there is still room for improvement. Summary of the Invention

[0004] To further improve the strength of water-stabilized weathered material, this application provides a water-stabilized weathered material for highway subgrade construction, its preparation method, and its application.

[0005] In the first aspect, this application provides a water-stabilized weathered material for highway subgrade construction, employing the following technical solution: A water-stabilized weathered material for highway subgrade construction comprises the following components in parts by weight: 100-120 parts water; 50-60 parts cement; 1000 portions of weathered material; 10-12 parts of compound bacterial solution; 10-12 parts urea; The preparation method of the compound bacterial solution is as follows: Step 1), mix water, yeast powder, peptone, beef extract, sodium chloride, manganese sulfate and urea to obtain liquid culture medium; Step 2): Add Bacillus pasteurellii, alkaliphilic halophilus, and alkali-resistant Narcissus to the liquid culture medium and culture until the OD value is 1-1.2 to obtain a compound bacterial solution.

[0006] By adopting the above technical solution and adding composite bacterial solution, the composite bacterial solution penetrates directly into the weathered material and produces calcium carbonate through metabolism. The calcium carbonate can effectively fill the pores of the water-stabilized weathered material, thereby significantly improving the strength of the water-stabilized weathered material after solidification.

[0007] By using a combination of Bacillus pasteurellii, alkaliphila, and alkali-resistant Narcissus, the activity of Bacillus pasteurellii can be significantly improved through the metabolites of alkaliphila and alkali-resistant Narcissus. This results in a better effect of Bacillus pasteurellii inducing calcium carbonate precipitation and better adaptability to alkaline cement environments, leading to higher strength of water-stabilized weathered materials.

[0008] Preferably, in step 2), the mass ratio of Bacillus pasteurellii, alkaliphila, and alkali-resistant Narcissus is 4-6:1-2:1-2.

[0009] By adopting the above technical solution and specifically selecting the mass ratio of Bacillus pasteurellii, alkaliphila, and alkali-resistant Narcissus, the effect of improving the activity of Bacillus pasteurellii is better, and the effect of improving the strength of water-stabilized weathered material is more significant.

[0010] Preferably, in step 1), the mass ratio of water, yeast powder, peptone, beef extract, sodium chloride, manganese sulfate, and urea is 938.95-949.97:18-22:5-6:3-5:4-6:0.03-0.05:20-22.

[0011] By adopting the above technical solution and specifically selecting the mass ratio of water, yeast powder, peptone, beef extract, sodium chloride, manganese sulfate, and urea, the effect of cultivating compound bacteria is better, which can promote the activity of Bacillus pasteurellii and further help improve the strength of water-stabilized weathered material.

[0012] Preferably, in step 2), the mass ratio of liquid culture medium, Bacillus pasteurellii, alkaliphilic halophilus, and alkali-resistant Narcissus is 1000:4-6:1-2:1-2.

[0013] By adopting the above technical solution and specifically selecting the mass ratio of liquid culture medium, Bacillus pasteurellii, alkaliphilic bacteria, and alkali-resistant Narcissus, the culture effect is better, and the waste of bacteria can be reduced, effectively controlling costs.

[0014] Preferably, in step 2), after adding Bacillus pasteurellii, alkaliphila, and alkali-resistant Narcissus to the liquid culture medium, the medium is cultured at a constant temperature of 30-32°C.

[0015] By adopting the above technical solution and culturing at 30-32℃, the cultivation efficiency is higher.

[0016] Preferably, the weathered material is a mixture of weathered sandstone and weathered sand, wherein the particle size of the weathered sandstone is ≤100mm and the particle size of the weathered sand is ≥0.075mm.

[0017] By adopting the above technical solution and using weathered sandstone and weathered sand composite, the porosity is effectively reduced, the density of water-stabilized weathered material is improved, and the strength of water-stabilized weathered material is enhanced.

[0018] Preferably, the mass ratio of weathered sandstone to weathered sand in the weathered material is 750-800:200-250.

[0019] By adopting the above technical solution and by specifically selecting the mass ratio of weathered sandstone and weathered sand, the porosity of water-stabilized weathered material is reduced more effectively, and the strength of water-stabilized weathered material is higher.

[0020] Secondly, this application provides a method for preparing water-stabilized weathered material for highway subgrade construction, employing the following technical solution: A method for preparing the above-mentioned water-stabilized weathered material for highway subgrade construction includes the following steps: Step 01), mix the cement and weathered material evenly to obtain the premix; Step 02), mix water, compound bacterial solution and urea to obtain premixed solution; Step 03) Spray the premixed liquid onto the premixed material and cure it to obtain water-stabilized weathered material for highway subgrade construction.

[0021] By adopting the above technical solution, the resulting water-stabilized weathered material has higher strength, does not require a large increase in cement usage, effectively controls costs, and is more environmentally friendly.

[0022] Thirdly, this application provides an application of water-stabilized weathered material for highway subgrade construction, employing the following technical solution: An application of the aforementioned water-stabilized weathered material for highway subgrade construction, wherein the water-stabilized weathered material is used in the construction subgrade, and the subgrade construction method is as follows: Step 001): Mix cement and weathered material evenly, lay it on the roadbed, level it, and form a premixed layer; Step 002), mix water, compound bacterial solution and urea to obtain premixed solution; Step 003): Spray the premixed liquid evenly onto the premixed material layer, compact it, and cure it to obtain the roadbed.

[0023] By adopting the above technical solutions, the constructed roadbed has higher strength, stronger load-bearing capacity for the road surface, and is better suited to highways with high load-bearing requirements.

[0024] In summary, this application has the following beneficial effects: 1. Because this application adds a compound bacterial solution, the compound bacterial solution penetrates directly into the weathered material and produces calcium carbonate through metabolism. The calcium carbonate can effectively fill the pores of the water-stabilized weathered material, thereby significantly improving the strength of the water-stabilized weathered material after curing.

[0025] 2. In this application, it is preferred to use Bacillus pasteurellii, alkali-loving halophiles and alkali-resistant Narcissus bacteria in combination. The metabolites of alkali-loving halophiles and alkali-resistant Narcissus bacteria can significantly improve the activity of Bacillus pasteurellii, making the effect of Bacillus pasteurellii inducing calcium carbonate precipitation better, and making it better adaptable to the alkaline cement environment, resulting in higher strength of water-stabilized weathered material.

[0026] 3. In this application, it is preferred to specifically select the mass ratio of Bacillus pasteurellii, alkali-loving halophilus, and alkali-resistant Narcissus to improve the activity of Bacillus pasteurellii and significantly enhance the strength of water-stabilized weathered material. Detailed Implementation

[0027] The present application will be further described in detail below with reference to the embodiments.

[0028] Example 1

[0029] A water-stabilized weathered material for highway subgrade construction, the preparation method includes the following steps: Step 01): Add 50kg of cement, 750kg of weathered sandstone, and 250kg of weathered sand into a mixer truck, and mix at 120r / min for 30min to obtain a premix.

[0030] Step 02): Mix 100kg of water, 10kg of compound bacterial solution, and 10kg of urea to obtain a premixed solution.

[0031] Step 03): Spread the premix evenly in the mold, then spray the premix liquid onto the premix, compact it with 10MPa pressure for 30 minutes, let it stand for 3 days, demold it, and let it stand for 28 days to obtain water-stabilized weathered material for highway subgrade construction.

[0032] The cement was purchased from Shandong Lianshan Cement Co., Ltd., and was P.O42.5 retarded ordinary Portland cement. The measured initial setting time was 330 min and the final setting time was 455 min.

[0033] The grain size of weathered sandstone is 50-100mm.

[0034] The particle size of weathered sand is 1-4mm.

[0035] Urea is sourced from commercially available products.

[0036] The compound bacterial solution was prepared in-house, and the preparation method is as follows: Step 1): Mix 949.97 kg of water, 18 kg of yeast powder, 5 kg of peptone, 3 kg of beef extract, 4 kg of sodium chloride, 0.03 kg of manganese sulfate, and 20 kg of urea evenly to obtain a liquid culture medium.

[0037] Step 2): Add 4 kg of Bacillus pasteurellii, 1 kg of alkaliphilic halophilus, and 1 kg of alkali-resistant Narcissus to the liquid culture medium and culture until the OD value is 1-1.2 to obtain a compound bacterial solution.

[0038] The yeast powder was sourced from commercially available sources.

[0039] Peptone is available commercially.

[0040] The beef extract is sourced from commercially available sources.

[0041] Sodium chloride is available commercially.

[0042] Manganese sulfate is sourced from commercially available sources.

[0043] Urea is sourced from commercially available products.

[0044] Pasteurella multocida was obtained from commercially available sources, strain number: ATCC 11859, lyophilized powder.

[0045] The alkalophilic halomonas was purchased from Beijing Bio-85197, lyophilized powder.

[0046] Alkali-resistant Narcissus was purchased from Beijing Bio-Bio Biotechnology Co., Ltd., product number: Bio-098748, as a lyophilized powder.

[0047] Example 2

[0048] A water-stabilized weathered material for highway subgrade construction, the preparation method includes the following steps: Step 01): Add 55kg of cement, 775kg of weathered sandstone, and 225kg of weathered sand into a mixer truck, and mix at 120r / min for 30min to obtain a premix.

[0049] Step 02): Mix 110kg of water, 11kg of compound bacterial solution, and 11kg of urea to obtain a premixed solution.

[0050] Step 03): Spread the premix evenly in the mold, then spray the premix liquid onto the premix, compact it with 10MPa pressure for 30 minutes, let it stand for 3 days, demold it, and let it stand for 28 days to obtain water-stabilized weathered material for highway subgrade construction.

[0051] The cement was purchased from Shandong Lianshan Cement Co., Ltd., and was P.O42.5 retarded ordinary Portland cement. The measured initial setting time was 330 min and the final setting time was 455 min.

[0052] The grain size of weathered sandstone is 50-100mm.

[0053] The particle size of weathered sand is 1-4mm.

[0054] Urea is sourced from commercially available products.

[0055] The compound bacterial solution was prepared in-house, and the preparation method is as follows: Step 1): Mix 944.46 kg of water, 20 kg of yeast powder, 5.5 kg of peptone, 4 kg of beef extract, 5 kg of sodium chloride, 0.04 kg of manganese sulfate, and 21 kg of urea evenly to obtain a liquid culture medium.

[0056] Step 2): Add 5 kg of Bacillus pasteurellii, 1.5 kg of alkaliphilic halophilus, and 1.5 kg of alkali-resistant Narcissus to the liquid culture medium and culture until the OD value is 1-1.2 to obtain a compound bacterial solution.

[0057] The yeast powder was sourced from commercially available sources.

[0058] Peptone is available commercially.

[0059] The beef extract is sourced from commercially available sources.

[0060] Sodium chloride is available commercially.

[0061] Manganese sulfate is sourced from commercially available sources.

[0062] Urea is sourced from commercially available products.

[0063] Pasteurella multocida was obtained from commercially available sources, strain number: ATCC 11859, lyophilized powder.

[0064] The alkalophilic halomonas was purchased from Beijing Bio-85197, lyophilized powder.

[0065] Alkali-resistant Narcissus was purchased from Beijing Bio-Bio Biotechnology Co., Ltd., product number: Bio-098748, as a lyophilized powder.

[0066] Example 3

[0067] A water-stabilized weathered material for highway subgrade construction, the preparation method includes the following steps: Step 01): Put 60kg of cement, 800kg of weathered sandstone, and 200kg of weathered sand into a mixer truck, rotate at 120r / min, and mix for 30min to obtain a premix.

[0068] Step 02): Mix 120kg of water, 12kg of compound bacterial solution, and 12kg of urea to obtain a premixed solution.

[0069] Step 03): Spread the premix evenly in the mold, then spray the premix liquid onto the premix, compact it with 10MPa pressure for 30 minutes, let it stand for 3 days, demold it, and let it stand for 28 days to obtain water-stabilized weathered material for highway subgrade construction.

[0070] The cement was purchased from Shandong Lianshan Cement Co., Ltd., and was P.O42.5 retarded ordinary Portland cement. The measured initial setting time was 330 min and the final setting time was 455 min.

[0071] The grain size of weathered sandstone is 50-100mm.

[0072] The particle size of weathered sand is 1-4mm.

[0073] Urea is sourced from commercially available products.

[0074] The compound bacterial solution was prepared in-house, and the preparation method is as follows: Step 1): Mix 938.95 kg of water, 22 kg of yeast powder, 6 kg of peptone, 5 kg of beef extract, 6 kg of sodium chloride, 0.05 kg of manganese sulfate, and 22 kg of urea evenly to obtain a liquid culture medium.

[0075] Step 2) Add 6 kg of Bacillus pasteurellii, 2 kg of alkaliphilic halophilus, and 2 kg of alkali-resistant Narcissus to the liquid culture medium and culture until the OD value is 1-1.2 to obtain a compound bacterial solution.

[0076] The yeast powder was sourced from commercially available sources.

[0077] Peptone is available commercially.

[0078] The beef extract is sourced from commercially available sources.

[0079] Sodium chloride is available commercially.

[0080] Manganese sulfate is sourced from commercially available sources.

[0081] Urea is sourced from commercially available products.

[0082] Pasteurella multocida was obtained from commercially available sources, strain number: ATCC 11859, lyophilized powder.

[0083] The alkalophilic halomonas was purchased from Beijing Bio-85197, lyophilized powder.

[0084] Alkali-resistant Narcissus was purchased from Beijing Bio-Bio Biotechnology Co., Ltd., product number: Bio-098748, as a lyophilized powder.

[0085] Comparative Example 1 A water-stabilized weathered material for highway subgrade construction differs from Example 2 only in that: Alkali-resistant Bacillus was used to replace alkali-loving halomonas in equal amounts, and alkali-resistant Narcissus was used to replace alkali-resistant Narcissus in equal amounts.

[0086] The alkali-resistant Bacillus was purchased from Beijing Bio-137836, lyophilized powder.

[0087] The *Delamydomonas dermatitidis* was purchased from Beijing Bio-Bio Biotechnology Co., Ltd., product number: Bio-05600, as a lyophilized powder.

[0088] Comparative Example 2 A water-stabilized weathered material for highway subgrade construction differs from Example 2 only in that: Alkali-resistant Bacillus was used to replace alkaliphilic halophilic bacteria in an equal amount.

[0089] The alkali-resistant Bacillus was purchased from Beijing Bio-137836, lyophilized powder.

[0090] Comparative Example 3 A water-stabilized weathered material for highway subgrade construction differs from Example 2 only in that: Alkali-resistant Narcissus was replaced with an equal amount of Alkali-resistant Narcissus.

[0091] The *Delamydomonas dermatitidis* was purchased from Beijing Bio-Bio Biotechnology Co., Ltd., product number: Bio-05600, as a lyophilized powder.

[0092] Comparative Example 4 A water-stabilized weathered material for highway subgrade construction differs from Example 2 only in that: Alkali-resistant Bacillus was used to replace alkali-loving halophiles in equal amounts, and alkali-resistant Narcissus was used to replace alkali-resistant Bacillus in equal amounts.

[0093] The alkali-resistant Bacillus was purchased from Beijing Bio-137836, lyophilized powder.

[0094] Comparative Example 5 A water-stabilized weathered material for highway subgrade construction differs from Example 2 only in that: Alkalophilic bacteria were replaced with an equal amount of *Alkalophilic halophytes*, and alkali-resistant *Narcissus* was replaced with an equal amount of *Alkalophilic halophytes*.

[0095] The *Delamydomonas dermatitidis* was purchased from Beijing Bio-Bio Biotechnology Co., Ltd., product number: Bio-05600, as a lyophilized powder.

[0096] Comparative Example 6 A water-stabilized weathered material for highway subgrade construction differs from Example 2 only in that: Alkali-resistant Narcissus was replaced with an equal amount of alkali-loving halophilic bacteria.

[0097] Comparative Example 7 A water-stabilized weathered material for highway subgrade construction differs from Example 2 only in that: Alkali-resistant Narcissus bacteria were used to replace alkaliphilic halophilic bacteria in equal amounts.

[0098] Experiment 1 According to the "Test Procedure for Inorganic Binder Stabilized Materials in Highway Engineering" (JTG3441-2024), specifically the "Test Method for Unconfined Compressive Strength of Inorganic Binder Stabilized Materials" (T0805-2024), the unconfined compressive strength of the water-stabilized weathered materials prepared in each example and comparative example was tested.

[0099] The size of the test sample is selected as φ150mm×150mm.

[0100] The detailed experimental data for Experiment 1 are shown in Table 1.

[0101] Table 1

[0102] According to the data in Table 1, the strength of the water-stabilized weathered material prepared in each embodiment is significantly higher than that in each comparative example. It can be seen that the composite bacterial solution prepared by adding Bacillus pasteurellii, alkali-loving halophilus, and alkali-resistant Narcissus in each embodiment can make Bacillus pasteurellii more active and better fill the pores of the water-stabilized weathered material by precipitating calcium carbonate. This results in higher density and significantly improved strength of the water-stabilized weathered material prepared in each embodiment, which can better meet the needs of highway engineering with high load-bearing requirements.

Claims

1. A water-stabilized weathered material for highway subgrade construction, characterized in that: The components include the following parts by mass: 100-120 parts water; 50-60 parts cement; 1000 portions of weathered material; 10-12 parts of compound bacterial solution; 10-12 parts urea; The preparation method of the compound bacterial solution is as follows: Step 1), mix water, yeast powder, peptone, beef extract, sodium chloride, manganese sulfate and urea to obtain liquid culture medium; Step 2): Add Bacillus pasteurellii, alkaliphilic halophilus, and alkali-resistant Narcissus to the liquid culture medium and culture until the OD value is 1-1.2 to obtain a compound bacterial solution.

2. The water-stabilized weathered material for highway subgrade construction according to claim 1, characterized in that: In step 2), the mass ratio of Bacillus pasteurellii, alkaliphila, and alkali-resistant Narcissus is 4-6:1-2:1-2.

3. The water-stabilized weathered material for highway subgrade construction according to claim 2, characterized in that: In step 1), the mass ratio of water, yeast powder, peptone, beef extract, sodium chloride, manganese sulfate, and urea is 938.95-949.97:18-22:5-6:3-5:4-6:0.03-0.05:20-22.

4. The water-stabilized weathered material for highway subgrade construction according to claim 3, characterized in that: In step 2), the mass ratio of liquid culture medium, Bacillus pasteurellii, alkaliphila, and alkali-resistant Narcissus is 1000:4-6:1-2:1-2.

5. The water-stabilized weathered material for highway subgrade construction according to claim 4, characterized in that: In step 2), after adding Bacillus pasteurellii, alkaliphila, and alkali-resistant Narcissus to the liquid culture medium, the medium is cultured at a constant temperature of 30-32℃.

6. The water-stabilized weathered material for highway subgrade construction according to claim 1, characterized in that: The weathered material is a mixture of weathered sandstone and weathered sand. The particle size of the weathered sandstone is ≤100mm, and the particle size of the weathered sand is ≥0.075mm.

7. The water-stabilized weathered material for highway subgrade construction according to claim 6, characterized in that: The mass ratio of weathered sandstone to weathered sand in the weathered material is 750-800:200-250.

8. A method for preparing water-stabilized weathered material for highway subgrade construction according to any one of claims 1-7, characterized in that: Includes the following steps: Step 01), mix the cement and weathered material evenly to obtain the premix; Step 02), mix water, compound bacterial solution, and urea to obtain a premixed solution; Step 03) Spray the premixed liquid onto the premixed material and cure it to obtain water-stabilized weathered material for highway subgrade construction.

9. The application of a water-stabilized weathered material for highway subgrade construction according to any one of claims 1-7, characterized in that: The water-stabilized weathered material used in the construction of the highway subgrade is employed in the subgrade construction, and the subgrade construction method is as follows: Step 001): Mix cement and weathered material evenly, lay it on the roadbed, level it, and form a premixed layer; Step 002), mix water, compound bacterial solution, and urea to obtain a premixed solution; Step 003): Spray the premixed liquid evenly onto the premixed material layer, compact it, and cure it to obtain the roadbed.

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