Aeolian sand-based fiber foam light soil and preparation method thereof

Abstract

The invention discloses aeolian sand-based fiber foam light soil and a preparation method thereof, and belongs to the technical field of road engineering materials, the light soil comprises the following components in parts by mass: 300-400 parts of cement, 5-10 parts of fiber, 400-440 parts of water, 3000-4000 parts of aeolian sand and foam liquid; the wet density of the light soil is controlled to be 600-700 kg / m < 3 >, the 7d unconfined compressive strength is 0.87-1.46 MPa, the 28d unconfined compressive strength is 1.85-2.18 MPa, and the 28d breaking strength is 1.24-1.50 MPa. The light soil has the advantages of excellent light weight, high strength, high fluidity, low cost and resource saving, and solves the problems that the existing foam light soil is insufficient in strength and easy to crack under the condition of low density.

Description

Technical Field

[0001] The invention relates to the technical field of road engineering materials, in particular to a wind-blown sand-based fiber foam lightweight soil and a preparation method thereof. Background Art

[0002] As a new type of roadbed filling material, foamed lightweight soil has many characteristics such as light weight, adjustable strength, strong fluidity, upright after solidification, and good thermal insulation performance. It is widely used in engineering projects such as roadbed widening, bridge abutment backfill, municipal renovation and expansion, etc., which effectively improves the integrity and construction convenience of the roadbed, and greatly solves the problems of uneven post-construction settlement and poor durability caused by roadbed loading. It is considered to be an excellent roadbed filling material. Using foamed lightweight soil in roadbed widening projects can, on the one hand, make full use of local raw soil as raw material and save engineering costs; on the other hand, using aeolian sand as the raw material of foamed lightweight soil can also turn waste into treasure and reduce the harm of building materials to the environment.

[0003] Traditional foamed lightweight soil usually uses river sand, mineral powder, fly ash, etc. as raw materials to prepare foamed lightweight soil to achieve the purpose of reducing construction costs and improving performance. However, for the arid desert areas in northwest my country, the above raw materials are not easy to obtain, which leads to increased construction costs for foamed lightweight soil construction in the area. Therefore, it is necessary to optimize the foamed lightweight soil to reduce the road construction cost in the arid desert areas in northwest China.

[0004] However, there are abundant aeolian sand resources in the area. Therefore, aeolian sand is used as the raw material of foam lightweight soil in the road construction process, and basalt fiber is added to it to improve its durability and mechanical properties. This has important economic significance for the construction of desert highways in the arid desert areas of Northwest China. Summary of the invention

[0005] In view of the problems existing in the prior art, the present invention provides a wind-blown sand-based fiber foam lightweight soil and a preparation method thereof. Wind-blown sand is used as the raw material soil of the foam lightweight soil, and basalt fiber is added thereto to improve its durability and mechanical properties, thereby ensuring the performance of the foam lightweight soil and reducing the road construction cost.

[0006] The present invention is achieved through the following technical solutions:

[0007] A wind-blown sand-based fiber foam lightweight soil comprises, by weight, 300-400 parts of cement, 5-10 parts of fiber, 400-440 parts of water, 3000-4000 parts of wind-blown sand and foam liquid.

[0008] Preferably, the foam liquid comprises 9 to 11 parts of foaming agent and 351 to 429 parts of water for the foaming agent.

[0009] Preferably, the aeolian sand has a bulk density of >1400 Kg / cm3, a gravity of >1.45 Kg / cm3, a mud content of <3%, a sulfate content of <0.5%, and a natural moisture content of 1% to 3%.

[0010] Preferably, the fiber is basalt fiber.

[0011] Preferably, the basalt fiber has a length of 5 to 12 mm, a diameter of 13 μm to 17 μm, a density ≥ 2.5 g / cm3, an elastic modulus of 91 to 110 GPa, a tensile strength of 3000 to 4800 MPa, and an elongation at break > 3%.

[0012] Preferably, the foaming liquid is an animal protein type foaming agent.

[0013] A method for preparing aeolian sand-based fiber foam lightweight soil comprises the following steps:

[0014] Step 1: 300-400 parts of cement, 5-10 parts of fiber, 400-440 parts of water, and 3000-4000 parts of aeolian sand are mixed uniformly to obtain aeolian sand-based fiber cement mortar;

[0015] Dilute 9 to 11 parts of a foaming agent to prepare foam;

[0016] Step 2, mixing the aeolian sand-based fiber cement mortar and the foam evenly to obtain the aeolian sand-based reinforced foam lightweight soil mortar;

[0017] Step 3: Harden the aeolian sand-based reinforced foam lightweight soil mortar to obtain the aeolian sand-based fiber foam lightweight soil.

[0018] Preferably, the preparation method of the aeolian sand-based fiber cement mortar is as follows:

[0019] First, 300-400 parts of cement, 5-10 parts of fiber, and 3000-4000 parts of aeolian sand are uniformly mixed to obtain aeolian sand-based fiber cement dry material;

[0020] Then, 400 to 440 parts of water are added into the aeolian sand-based fiber cement dry material, and the mixture is stirred evenly to obtain aeolian sand-based fiber cement mortar.

[0021] Preferably, the method for hardening the sand-based reinforced foam lightweight soil mortar is as follows:

[0022] Pour the aeolian sand-based reinforced foam lightweight soil mortar into a mold for static pressure molding, and demould after natural curing for 2 to 4 days to obtain pre-solidified aeolian sand-based reinforced foam lightweight soil;

[0023] The pre-solidified aeolian sand-based reinforced foam lightweight soil is naturally cured for 28 days to obtain the aeolian sand-based reinforced foam lightweight soil.

[0024] A desert highway, the roadbed of which is filled with the aeolian sand-based fiber foam lightweight soil according to any one of claims 1 to 6.

[0025] Compared with the prior art, the present invention has the following beneficial technical effects:

[0026] The aeolian sand-based fiber foam lightweight soil provided by the present invention is prepared from cement, foaming liquid, fiber, aeolian sand and water. The aeolian sand is used as the raw material soil of the foam lightweight soil in the road construction process, and basalt fiber is added thereto to improve its durability and mechanical properties. The lightweight soil has a 32% higher compressive strength and a 40% higher flexural strength than traditional foam lightweight soil, thereby solving the technical problems of insufficient strength and easy cracking of the existing foam lightweight soil under low-density conditions, and can alleviate the tense situation of shortage of road sand and gravel and fill materials, thereby achieving the purpose of saving resources and reducing engineering costs.

[0027] The method for preparing aeolian sand-based fiber foam lightweight soil can complete the preparation of lightweight soil in three steps, so the preparation process is simple and has the potential for large-scale promotion and utilization; it can alleviate the tense situation of shortage of road sand and gravel and fill materials, and achieve the purpose of saving resources and reducing engineering costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The present invention is a flow chart of the preparation method of aeolian sand-based fiber foam lightweight soil. DETAILED DESCRIPTION

[0029] The present invention will be further described in detail below in conjunction with the accompanying drawings, which are intended to explain the present invention rather than to limit it.

[0030] On one hand, the present invention provides a wind-blown sand-based fiber foam lightweight soil, which comprises, by weight, 300-400 parts of cement, 5-10 parts of fiber, 400-440 parts of water, 3000-4000 parts of wind-blown sand and foam liquid;

[0031] The foam liquid comprises 9 to 11 parts of foaming agent and 351 to 429 parts of water for the foaming agent.

[0032] The cement is made of P·O42.5 common silicate, with a fineness (80 μm square mesh) of 7.2% and a specific surface area of ​​383 m 2 / kg, initial setting time 181min, final setting time 214min, 3-day and 28-day compressive strengths 29.5MPa and 49.4MPa respectively;

[0033] The bulk density of the aeolian sand is > 1400 Kg / cm 3 , weight>1.45Kg / cm 3, mud content <3%, sulfate content <0.5%, natural water content 1% to 3%;

[0034] The fiber is basalt fiber with a length of 5 to 12 mm, a diameter of 13 μm to 17 μm, and a density of ≥2.5 g / cm 3 , elastic modulus is 91~110GPa, tensile strength is 3000~4800MPa, and elongation at break is >3%.

[0035] The foaming liquid is made by diluting animal protein foaming agent 40 times, the foaming ratio is 800-1000 times, and the density of the foam is 40-50kg / m 3 ;

[0036] Another aspect of the present invention provides a method for preparing aeolian sand-based fiber foam lightweight soil, comprising the following steps:

[0037] Step 1, diluting 9 to 11 parts of a foaming agent to prepare foam;

[0038] Specifically, the foaming agent and water are diluted in a ratio of 1:(30-40) times to form a foam liquid, and the foam liquid is blown by an air compressor to form foam.

[0039] Step 2: 300-400 parts of cement, 5-10 parts of fiber, 400-440 parts of water, and 3000-4000 parts of aeolian sand are mixed uniformly by mass to obtain aeolian sand-based fiber cement mortar;

[0040] Step 3: Evenly mix the foam prepared in step 1 and the aeolian sand-based fiber cement mortar prepared in step 2 to obtain aeolian sand-based reinforced foam lightweight soil slurry.

[0041] Step 4: air-drying the aeolian sand-based reinforced foam lightweight soil slurry to obtain the aeolian sand-based fiber foam lightweight soil.

[0042] This preparation method uses aeolian sand as raw material, and the prepared foamed lightweight soil has excellent mechanical properties and environmental protection characteristics, and the preparation process is simple, with the potential for large-scale promotion and utilization; it can alleviate the tense situation of shortage of road sand and gravel and fill materials, achieve the purpose of saving resources and reducing engineering costs, and has significant economic and social environmental benefits.

[0043] Example 1

[0044] A method for preparing aeolian sand-based fiber foam lightweight soil comprises the following steps:

[0045] Step 1: Weigh 9 to 11 parts of foaming agent by mass.

[0046] Step 2, mixing the foaming agent with water in a ratio of 1:30, and then passing the foaming agent through an air compressor to prepare foam;

[0047] Step 3, 300-400 parts of cement, 5-10 parts of fiber and 3000-4000 parts of aeolian sand are put into a mixer and dry mixed for 1 minute to fully mix the materials to obtain aeolian sand-based fiber cement dry material;

[0048] Step 4, pouring 400-440 parts of water into a stirrer filled with fiber cement dry material, stirring for 2 minutes to make the slurry uniform, to obtain aeolian sand-based fiber cement mortar;

[0049] Step 5, pour the foam into the aeolian sand-based fiber cement mortar, and stir together for 2 minutes to obtain the aeolian sand-based reinforced foam lightweight soil mortar;

[0050] Step 6: Pour the aeolian sand-based reinforced foam lightweight soil mortar into a mold, statically press into shape, and naturally cure for 2-4 days to obtain pre-solidified aeolian sand-based reinforced foam lightweight soil.

[0051] Step 7: demould the pre-solidified aeolian sand-based reinforced foam lightweight soil mold, and naturally cure it to an age of 28 days to obtain the aeolian sand-based reinforced foam lightweight soil.

[0052] Example 2

[0053] A wind-blown sand-based fiber foam lightweight soil comprises, by weight, 300 parts of cement, 5 parts of basalt fiber, 400 parts of water, 4000 parts of wind-blown sand, 11 parts of foaming agent, and 429 parts of foaming agent water.

[0054] The method for preparing aeolian sand-based fiber foam lightweight soil comprises the following steps:

[0055] Step 1: Weigh the foaming agent and water for the foaming agent according to the formula, mix the foaming agent and water in a ratio of 1:30, and then pass the foaming agent through an air compressor to prepare 50kg / m3 of foam;

[0056] Step 2: After weighing the cement, aeolian sand and fiber required for the foam, divide each mass into 3 batches and put them into a mixer at a speed of 140±5rpm for dry mixing for 3 minutes to fully mix the materials;

[0057] Step 3, weigh the water and pour it into the stirrer filled with dry materials, stir for 2 minutes to make the slurry evenly stirred, and obtain basalt fiber cement aeolian sand slurry;

[0058] Step 4: After weighing the foam with a measuring cup, pour it into the basalt fiber cement aeolian sand mortar, stir them together for 2 minutes, measure the flow value and then pour it into the mold. After curing and hardening, aeolian sand-based fiber foam lightweight soil is obtained.

[0059] Example 3

[0060] A wind-blown sand-based fiber foam lightweight soil comprises, by weight, 350 parts of cement, 7 parts of basalt fiber, 415 parts of water, 3550 parts of wind-blown sand, 10 parts of foaming agent and 389 parts of water for the foaming agent.

[0061] The method for preparing aeolian sand-based fiber foam lightweight soil comprises the following steps:

[0062] Step 1: Weigh the foaming agent and foaming agent water according to the formula, mix the foaming agent and water in a ratio of 1:30, and then pass the foaming agent through an air compressor to prepare 50kg / m 3 Foam;

[0063] Step 2: After weighing the cement, aeolian sand and fiber required for the foam, divide each mass into 3 batches and put them into a mixer at a speed of 140±5rpm for dry mixing for 3 minutes to fully mix the materials;

[0064] Step 3, weigh the water and pour it into the stirrer filled with dry materials, stir for 2 minutes to make the slurry evenly stirred, and obtain basalt fiber cement aeolian sand slurry;

[0065] Step 4: After weighing the foam with a measuring cup, pour it into the basalt fiber cement aeolian sand mortar, stir them together for 2 minutes, measure the flow value and then pour it into the mold. After curing and hardening, aeolian sand-based fiber foam lightweight soil is obtained.

[0066] Example 4

[0067] A wind-blown sand-based fiber foam lightweight soil comprises, by weight, 400 parts of cement, 10 parts of basalt fiber, 440 parts of water, 3000 parts of wind-blown sand, 9 parts of foaming agent, and 351 parts of foaming agent water.

[0068] The method for preparing aeolian sand-based fiber foam lightweight soil comprises the following steps:

[0069] Step 1: Weigh the foaming agent and foaming agent water according to the formula, mix the foaming agent and water in a ratio of 1:30, and then pass the foaming agent through an air compressor to prepare 50kg / m 3 Foam;

[0070] Step 2: After weighing the cement, aeolian sand and fiber required for the foam, divide each mass into 3 batches and put them into a mixer at a speed of 140±5rpm for dry mixing for 3 minutes to fully mix the materials;

[0071] Step 3, weigh the water and pour it into the stirrer filled with dry materials, stir for 2 minutes to make the slurry evenly stirred, and obtain basalt fiber cement aeolian sand slurry;

[0072] Step 4: After weighing the foam with a measuring cup, pour it into the basalt fiber cement aeolian sand mortar, stir them together for 2 minutes, measure the flow value and then pour it into the mold. After curing and hardening, aeolian sand-based fiber foam lightweight soil is obtained.

[0073] Example 5

[0074] A highway in a desert area, wherein the roadbed of the highway is filled with the above-mentioned wind-blown sand-based fiber foam lightweight soil.

[0075] It should be noted that the aeolian sand-based fiber foam lightweight soil is suitable for the roadbed of any highway, but is used in desert highways because aeolian sand is easily obtained in the desert, thereby minimizing the manufacturing cost of the highway; in addition, the aeolian sand-based fiber foam lightweight soil can be used in highways of different grades, such as expressways.

[0076] The aeolian sand-based fiber foam lightweight soil of the present invention is prepared from cement, foaming liquid, fiber, aeolian sand and water. The wet density of the lightweight soil is 600-700 kg / m 3 , 7d unconfined compressive strength 0.87~1.46MPa, 28d unconfined compressive strength 1.85~2.18MPa, 28d flexural strength 1.24~1.50MPa, solve the technical problems of insufficient strength and easy cracking of existing foam lightweight soil under low density conditions, and have the advantages of excellent light weight, high strength, high fluidity, low cost and resource conservation. It meets the strength requirements of embankment filling "Highway Roadbed Design Code" (JTGD30-2015), and the compressive strength is increased by 32% and the flexural strength is increased by 40% compared with traditional foam lightweight soil. This is of great significance to solve the strength shortcomings of traditional foam lightweight soil in engineering applications, increase durability, and maintain good ease of construction and stability.

[0077] The foamed lightweight soil prepared with aeolian sand as raw material has excellent mechanical properties and environmental protection characteristics, and the preparation process is simple, with the potential for large-scale promotion and utilization; it can alleviate the tense situation of shortage of road sand and gravel and fill materials, achieve the purpose of saving resources and reducing engineering costs, and has significant economic and social environmental benefits.

[0078] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A wind-blown sand-based fiber foam lightweight soil, characterized in that: Calculated by mass, it includes 300-400 parts of cement, 5-10 parts of fiber, 400-440 parts of water, 3000-4000 parts of aeolian sand and foam liquid.

2. The aeolian sand-based fiber foam lightweight soil according to claim 1, characterized in that: The foam liquid comprises 9 to 11 parts of foaming agent and 351 to 429 parts of water for the foaming agent.

3. The aeolian sand-based fiber foam lightweight soil according to claim 1, characterized in that: The bulk density of the aeolian sand is > 1400 Kg / cm 3 , weight>1.45Kg / cm 3 , mud content <3%, sulfate content <0.5%, and natural water content 1% to 3%.

4. The aeolian sand-based fiber foam lightweight soil according to claim 1, characterized in that: The fiber is basalt fiber.

5. The aeolian sand-based fiber foam lightweight soil according to claim 4, characterized in that: The basalt fiber has a length of 5 to 12 mm, a diameter of 13 μm to 17 μm, and a density of ≥2.5 g / cm 3 , elastic modulus is 91~110GPa, tensile strength is 3000~4800MPa, and elongation at break is >3%.

6. The aeolian sand-based fiber foam lightweight soil according to claim 1, characterized in that: The foaming liquid is an animal protein type foaming agent.

7. A method for preparing aeolian sand-based fiber foam lightweight soil according to any one of claims 1 to 6, characterized in that: The process includes: Step 1: 300-400 parts of cement, 5-10 parts of fiber, 400-440 parts of water, and 3000-4000 parts of aeolian sand are mixed uniformly to obtain aeolian sand-based fiber cement mortar; Dilute 9 to 11 parts of a foaming agent to prepare foam; Step 2, mixing the aeolian sand-based fiber cement mortar and the foam evenly to obtain the aeolian sand-based reinforced foam lightweight soil mortar; Step 3: Harden the aeolian sand-based reinforced foam lightweight soil mortar to obtain the aeolian sand-based fiber foam lightweight soil.

8. The method for preparing aeolian sand-based fiber foam lightweight soil according to claim 7, characterized in that: The preparation method of the aeolian sand-based fiber cement mortar is as follows: First, 300-400 parts of cement, 5-10 parts of fiber, and 3000-4000 parts of aeolian sand are uniformly mixed to obtain aeolian sand-based fiber cement dry material; Then, 400 to 440 parts of water are added into the aeolian sand-based fiber cement dry material, and the mixture is stirred evenly to obtain aeolian sand-based fiber cement mortar.

9. The method for preparing aeolian sand-based fiber foam lightweight soil according to claim 7, characterized in that: The method for hardening the sand-based reinforced foam lightweight soil mortar is as follows: Pour the aeolian sand-based reinforced foam lightweight soil mortar into a mold for static pressure molding, and demould after natural curing for 2 to 4 days to obtain pre-solidified aeolian sand-based reinforced foam lightweight soil; The pre-solidified aeolian sand-based reinforced foam lightweight soil is naturally cured for 28 days to obtain the aeolian sand-based reinforced foam lightweight soil.

10. A desert highway, characterized in that: The roadbed of the desert highway is filled with the aeolian sand-based fiber foam lightweight soil according to any one of claims 1 to 6.

Images