Foaming cement for roadbed filling and preparation method and application thereof

Abstract

The invention relates to the technical field of foaming cement, and provides foaming cement for roadbed filling as well as a preparation method and application thereof. The foam cement for roadbed filling comprises the following components in parts by weight: 120-140 parts of sulphoaluminate cement, 80-90 parts of water, 10-25 parts of chromite powder, 8-16 parts of polyvinyl alcohol fiber, 5-10 parts of polypropylene fiber, 35-45 parts of aggregate, 4-8 parts of a water reducing agent, 4-8 parts of a foaming agent and 1-2 parts of an air entraining agent. According to the technical scheme, the problems of poor strength and insufficient durability of the foaming cement in the prior art are solved.

Description

Technical Field

[0001] The invention relates to the technical field of foamed cement, and in particular to foamed cement for roadbed filling and a preparation method and application thereof. Background Art

[0002] Foamed cement, also known as foamed concrete, lightweight concrete, etc., is a new type of building energy-saving material that is waste-recycling, environmentally friendly, energy-saving, low-cost and non-flammable. In recent years, with the continuous expansion of urban construction, roads as the main arteries of communication in cities will inevitably increase. During road construction, the roadbed, as the foundation of the road, has an important impact on the performance of the road surface. The roadbed should be stable and dense, provide uniform support for the road surface structure, and not produce uneven deformation under the action of the environment and load. Its quality determines the overall stability of the road. Therefore, the materials used in roadbed filling are particularly important. Traditional roadbed backfill materials are often covered soil and concrete, which have heavy weight. Foamed cement is lightweight and has little disturbance to other structural layers of the project, reduces post-construction settlement and uneven settlement, and can ensure the stability of the road structure layer. It can be seen that foamed cement is a good roadbed backfill material with broad application prospects. However, foamed cement still has problems such as poor strength and insufficient durability to be solved. Summary of the invention

[0003] The invention provides foamed cement for roadbed filling and a preparation method and application thereof, which solve the problems of poor strength and insufficient durability of the foamed cement in the related art.

[0004] The technical solution of the present invention is as follows: The invention provides foamed cement for roadbed filling, which comprises the following components in parts by weight: 120-140 parts of sulphoaluminate cement, 80-90 parts of water, 10-25 parts of chromite powder, 8-16 parts of polyvinyl alcohol fiber, 5-10 parts of polypropylene fiber, 35-45 parts of aggregate, 4-8 parts of water reducer, 4-8 parts of foaming agent and 1-2 parts of air entraining agent.

[0005] As a further technical solution, the aggregate includes fly ash and perlite in a mass ratio of 10:1 to 8.

[0006] As a further technical solution, the particle size of the fly ash is 100-200 μm; the particle size of the perlite is 0.5 mm-1 mm; The polyvinyl alcohol fiber has a diameter of 5-15 μm and a length of 1-2 mm; The polypropylene fiber has a diameter of 20-30 μm and a length of 1-2 mm.

[0007] As a further technical solution, the water reducer includes a polycarboxylic acid water reducer; The foaming agent includes one or both of a sulfonate foaming agent and a protein foaming agent; The air entraining agent includes a rosin resin type air entraining agent.

[0008] As a further technical solution, the mass ratio of the chromite powder, polyvinyl alcohol fiber and polypropylene fiber is 12~22:10:8.

[0009] In the present invention, when the mass ratio of chromite powder, polyvinyl alcohol fiber and polypropylene fiber in the foamed cement matrix is ​​12-22:10:8, the strength and durability of the foamed cement are further improved.

[0010] As a further technical solution, the chromite powder is modified by hydroxypropyl-β-cyclodextrin.

[0011] As a further technical solution, the modification method comprises the following steps: after mixing hydroxypropyl-β-cyclodextrin, a coupling agent and a solvent, adding chromite powder, continuing to mix, and drying.

[0012] As a further technical solution, the mass ratio of hydroxypropyl-β-cyclodextrin, coupling agent and chromite powder is 0.1~0.3:0.3:1; The solvent during the dissolution is an alcohol solvent; The coupling agent is a water-insoluble coupling agent; The mass ratio of the alcohol solvent to the coupling agent is 15-25:1.

[0013] In the present invention, chromite powder is modified with hydroxypropyl-β-cyclodextrin and then added into the foamed cement matrix, and cooperates with polyvinyl alcohol fiber and polypropylene fiber to further improve the strength and durability of the foamed cement.

[0014] The present invention also provides a method for preparing the foamed cement for roadbed filling, comprising the following steps: The components of the foamed cement for roadbed filling are mixed to obtain the foamed cement.

[0015] The invention also proposes the application of the foamed cement for roadbed filling or the foamed cement prepared by the preparation method in roadbed filling.

[0016] The working principle and beneficial effects of the present invention are: In the present invention, chromite powder, polyvinyl alcohol fiber and polypropylene fiber are introduced into the foamed cement matrix, and the three cooperate with each other to build a dense internal network between the cement and other components, thereby significantly improving the strength and durability of the foamed cement. DETAILED DESCRIPTION

[0017] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] Example 1 The foamed cement for roadbed filling comprises the following components in parts by weight: 120 parts of sulphoaluminate cement (model 42.5), 80 parts of water, 10 parts of chromite powder, 8 parts of polyvinyl alcohol fiber, 5 parts of polypropylene fiber, 35 parts of aggregate, 4 parts of polycarboxylate water reducer (model HPEG-2400), 4 parts of sodium dodecylbenzene sulfonate, and 1 part of sodium rosin acid; The aggregates include fly ash and perlite in a mass ratio of 10:1; the particle size of the fly ash is 100 μm; the particle size of the perlite is 0.5 mm; the diameter of the polyvinyl alcohol fiber is 5 μm and the length is 1 mm; the diameter of the polypropylene fiber is 30 μm and the length is 2 mm; The method for preparing foamed cement for roadbed filling comprises the following steps: The components of the foamed cement for roadbed filling are mixed to obtain the foamed cement.

[0019] Example 2 The foamed cement for roadbed filling comprises the following components in parts by weight: 140 parts of sulphoaluminate cement (model 42.5), 90 parts of water, 25 parts of chromite powder, 16 parts of polyvinyl alcohol fiber, 10 parts of polypropylene fiber, 45 parts of aggregate, 8 parts of polycarboxylate water reducer (model HPEG-2400), 8 parts of sodium dodecylbenzene sulfonate, and 2 parts of sodium rosinate; The aggregates include fly ash and perlite in a mass ratio of 10:8; the particle size of the fly ash is 200 μm; the particle size of the perlite is 1 mm; the diameter of the polyvinyl alcohol fiber is 15 μm and the length is 2 mm; the diameter of the polypropylene fiber is 20 μm and the length is 1 mm; The method for preparing foamed cement for roadbed filling comprises the following steps: The components of the foamed cement for roadbed filling are mixed to obtain the foamed cement.

[0020] Example 3 The foamed cement for roadbed filling comprises the following components in parts by weight: 130 parts of sulphoaluminate cement (model 42.5), 80 parts of water, 10 parts of chromite powder, 10 parts of polyvinyl alcohol fiber, 8 parts of polypropylene fiber, 35 parts of aggregate, 4 parts of polycarboxylate water reducer (model HPEG-2400), 6 parts of sodium dodecylbenzene sulfonate, and 1 part of sodium rosinate; The aggregates include fly ash and perlite in a mass ratio of 10:3; the particle size of fly ash is 200 μm; the particle size of perlite is 0.75 mm; the diameter of polyvinyl alcohol fiber is 15 μm and the length is 1 mm; the diameter of polypropylene fiber is 20 μm and the length is 2 mm; The method for preparing foamed cement for roadbed filling comprises the following steps: The components of the foamed cement for roadbed filling are mixed to obtain the foamed cement.

[0021] Example 4 The only difference between this embodiment and embodiment 3 is that the components of the foamed cement for roadbed filling include 16 parts of chromite powder, 6.7 parts of polyvinyl alcohol fibers, and 5.3 parts of polypropylene fibers.

[0022] Example 5 The only difference between this embodiment and embodiment 3 is that the components of the foamed cement for roadbed filling include 11.2 parts of chromite powder, 9.3 parts of polyvinyl alcohol fibers, and 7.5 parts of polypropylene fibers.

[0023] Example 6 The only difference between this embodiment and embodiment 3 is that the components of the foamed cement for roadbed filling include 15.4 parts of chromite powder, 7 parts of polyvinyl alcohol fiber, and 5.6 parts of polypropylene fiber.

[0024] Example 7 The difference between this embodiment and embodiment 6 is that the chromite powder is modified by hydroxypropyl-β-cyclodextrin; The modification treatment method comprises the following steps: mixing hydroxypropyl-β-cyclodextrin, coupling agent KH-570 and ethanol, adding chromite powder, continuing to mix, and drying; The mass ratio of hydroxypropyl-β-cyclodextrin, coupling agent KH-570, and chromite powder is 0.3:0.3:1; The mass ratio of ethanol to coupling agent KH-570 is 25:1.

[0025] Example 8 The difference between this embodiment and embodiment 7 is that the chromite powder is modified by hydroxypropyl-β-cyclodextrin; The modification treatment method comprises the following steps: mixing hydroxypropyl-β-cyclodextrin, coupling agent KH-570 and ethanol, adding chromite powder, continuing to mix, and drying; The mass ratio of hydroxypropyl-β-cyclodextrin, coupling agent KH-570, and chromite powder is 0.1:0.3:1; The mass ratio of ethanol to coupling agent KH-570 is 15:1.

[0026] Comparative Example 1 The difference between this embodiment and embodiment 3 is that polyvinyl alcohol fiber is not added, and 15.6 parts of chromite powder and 12.4 parts of polypropylene fiber are added.

[0027] Comparative Example 2 The difference between this embodiment and embodiment 3 is that no polypropylene fiber is added, and 14 parts of chromite powder and 14 parts of polyvinyl alcohol fiber are added.

[0028] Comparative Example 3 The difference between this embodiment and embodiment 3 is that chromite powder is not added, and 15.6 parts of polyvinyl alcohol fiber and 12.4 parts of polypropylene fiber are added.

[0029] According to the test method in standard JG / T 266-2011 "Foamed Concrete", the 28d compressive strength of the foamed cement prepared in Examples 1 to 8 and Comparative Examples 1 to 3 was tested respectively, and then the freeze-thaw resistance cycle experiment was carried out, with -18°C insulation for 3h and 20°C insulation for 6h as one cycle. After 50 cycles, the compressive strength was tested again, and the compressive strength change rate was calculated. The test results are shown in Table 1 below.

[0030] Table 1 Performance test

[0031] Compared with Comparative Examples 1 to 3, the foamed cements prepared in Examples 1 to 8 have higher 28d compressive strength, and the rate of change of compressive strength after the freeze-thaw cycle experiment is smaller, indicating that by introducing chromite powder, polyvinyl alcohol fiber and polypropylene fiber into the foamed cement matrix, the three cooperate with each other to build a dense internal network between components such as cement, thereby significantly improving the strength and durability of the foamed cement.

[0032] Compared with Examples 3 and 4, the foamed cement prepared in Examples 5 and 6 has higher 28d compressive strength and a smaller change rate of compressive strength after the freeze-thaw cycle experiment, indicating that when the mass ratio of chromite powder, polyvinyl alcohol fiber and polypropylene fiber in the foamed cement matrix is ​​12 to 22:10:8, the strength and durability of the foamed cement are further improved.

[0033] Compared with Example 6, the foamed cement prepared in Examples 7-8 has higher 28d compressive strength, and the rate of change of compressive strength after freeze-thaw cycle experiment is smaller, indicating that the chromite ore powder is modified with hydroxypropyl-β-cyclodextrin and then added to the foamed cement matrix, which cooperates with the polyvinyl alcohol fiber and the polypropylene fiber to further improve the strength and durability of the foamed cement.

[0034] 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. Foamed cement for roadbed filling, characterized in that: The invention comprises the following components in parts by weight: 120-140 parts of sulphoaluminate cement, 80-90 parts of water, 10-25 parts of chromite powder, 8-16 parts of polyvinyl alcohol fiber, 5-10 parts of polypropylene fiber, 35-45 parts of aggregate, 4-8 parts of water reducing agent, 4-8 parts of foaming agent and 1-2 parts of air entraining agent.

2. The foamed cement for roadbed filling according to claim 1, characterized in that: The aggregate includes fly ash and perlite in a mass ratio of 10:1-8.

3. The foamed cement for roadbed filling according to claim 2, characterized in that: The particle size of the fly ash is 100-200 μm; the particle size of the perlite is 0.5 mm-1 mm; The polyvinyl alcohol fiber has a diameter of 5-15 μm and a length of 1-2 mm; The polypropylene fiber has a diameter of 20-30 μm and a length of 1-2 mm.

4. The foamed cement for roadbed filling according to claim 3, characterized in that: The water reducing agent includes a polycarboxylic acid water reducing agent; The foaming agent includes one or both of a sulfonate foaming agent and a protein foaming agent; The air entraining agent includes a rosin resin type air entraining agent.

5. The foamed cement for roadbed filling according to claim 2, characterized in that: The mass ratio of the chromite powder, polyvinyl alcohol fiber and polypropylene fiber is 12-22:10:

8.

6. The foamed cement for roadbed filling according to claim 5, characterized in that: The chromite powder is modified by hydroxypropyl-β-cyclodextrin.

7. The foamed cement for roadbed filling according to claim 5, characterized in that: The modification treatment method comprises the following steps: after mixing hydroxypropyl-β-cyclodextrin, a coupling agent and a solvent, adding chromite powder, continuing to mix, and drying.

8. The foamed cement for roadbed filling according to claim 1, characterized in that: The mass ratio of hydroxypropyl-β-cyclodextrin, coupling agent and chromite powder is 0.1-0.3:0.3:1; The solvent during the dissolution is an alcohol solvent; The coupling agent is a water-insoluble coupling agent; The mass ratio of the alcohol solvent to the coupling agent is 15-25:

1.

9. The method for preparing foamed cement for roadbed filling according to any one of claims 1 to 8, characterized in that: The following steps are involved: The components of the foamed cement for roadbed filling are mixed to obtain the foamed cement.

10. Use of the foamed cement for roadbed filling according to any one of claims 1 to 8 or the foamed cement prepared by the preparation method according to claim 9 in roadbed filling.

Images