A foamed concrete sound barrier and its preparation method

Abstract

The present invention relates to the technical field of cement-based building materials, and in particular to a foamed concrete sound barrier and a preparation method thereof. The present invention is based on an active powder concrete system, and adopts high-alumina cement, silicate cement, desulfurized gypsum, phosphorus slag powder, and modified zeolite powder as cementitious materials. The hydration processes cooperate with each other and the strength is high. Steel fiber is added to improve the rigidity and strength of the foamed concrete. The modified zeolite powder is also used as a gas-generating component, and is combined with lignin sulfonate and millimeter-sized SAP particles to introduce hierarchical connected pores to improve the foamed concrete sound barrier without significantly reducing the mechanical properties of the concrete. In addition to the air-entraining effect, the lignin sulfonate also exerts a synergistic water-reducing effect with a polycarboxylic acid water-reducer, thereby improving the fluidity of the foamed concrete, thereby preparing a foamed concrete sound barrier with good workability, high mechanical properties, and excellent sound insulation effect.

Description

Technical Field

[0001] The present invention relates to the technical field of cement-based building materials, and in particular to a foamed concrete sound barrier and a preparation method thereof. Background Art

[0002] The rapid development of transportation, especially the development of highways and urban expressways, coupled with the increase in motor vehicles, has brought about a large amount of traffic noise. Measures to reduce traffic noise include improving road structure, adding sound-absorbing and noise-reducing facilities, etc. Among them, setting up sound barriers is a commonly used noise reduction measure.

[0003] At present, commonly used sound barriers include metal sound barriers, cement sound barriers, glued wood chip boards, fiberglass sound insulation boards, etc. The strength of the structure of this type of board is relatively low, and it only serves as a lightweight porous sound-absorbing component. A large number of reinforcement facilities are required during the construction process, and the amount of consumables is large. During use, problems such as metal modification, natural weathering and damage are prone to occur. Summary of the Invention

[0004] In order to solve the problems existing in the prior art, the present invention provides a foamed concrete sound barrier and a preparation method thereof. The present invention is based on an active powder concrete system, and adopts high-alumina cement, silicate cement, desulfurized gypsum, phosphorus slag powder, and modified zeolite powder as cementitious materials. The hydration processes cooperate with each other and the strength is high. The addition of steel fiber improves the stiffness and strength of the foamed concrete. The modified zeolite powder is also used as a gas-generating component, and is combined with lignin sulfonate and millimeter-sized SAP particles to introduce hierarchical connected pores to improve the foamed concrete sound barrier without significantly reducing the mechanical properties of the concrete. In addition to the air-entraining effect, lignin sulfonate also exerts a synergistic water-reducing effect with polycarboxylic acid water-reducing agent to improve the fluidity of the foamed concrete, thereby preparing a foamed concrete sound barrier with good workability, short setting time, high mechanical properties, and excellent sound insulation effect.

[0005] Specifically, the foamed concrete sound barrier of the present invention is composed of the following raw materials in parts by weight:

[0006] 100-180 parts of high alumina cement,

[0007] 90-120 parts of Portland cement,

[0008] 30-50 parts of desulfurized gypsum,

[0009] 50-80 parts of phosphorus slag powder,

[0010] 80-100 parts of modified zeolite powder,

[0011] 60-80 parts of steel fiber,

[0012] 10-15 parts of polycarboxylate water reducer,

[0013] 2-5 parts of lignin sulfonate,

[0014] 3-6 parts of millimeter-sized SAP particles,

[0015] 100-120 parts water,

[0016] The modification process of the modified zeolite powder is as follows: crushing the zeolite powder to 0.1-0.3 mm and calcining at 400-500°C.

[0017] The selection of foaming agent for foamed concrete is the key. Most of the commonly used concrete foaming agents in the prior art are surfactants such as sodium dodecylbenzenesulfonate and rosin. However, the pores prepared by the above-mentioned foaming agents are mostly closed pores, and the pore walls are thin and the supporting force is weak. The prepared foamed concrete has good thermal insulation performance, but poor mechanical properties. The present invention is to prepare a high-strength foamed concrete sound barrier that does not require steel plates or steel frames as protective layers, and a lot of research is conducted on foaming pore-forming components. Specifically, the present invention adopts modified zeolite powder, lignin sulfonate and millimeter-sized SAP particles as foaming pore-forming components. After crushing and calcining, the zeolite powder contains a large number of pores and absorbs air, which gasifies and forms bubbles in the concrete slurry. Lignin sulfonate always forms micron-sized bubbles during the slurry stirring process. SAP particles can absorb moisture and are often used as internal curing materials. As inert particles, they will also introduce holes. The pore walls produced by the three form a graded combination and are interconnected, which greatly improves the sound insulation effect of the concrete sound barrier.

[0018] Preferably, the strength grade of the high alumina cement is ≥42.5.

[0019] Preferably, the silicate cement has a strength grade of ≥52.5 and a specific surface area of ≥320m 2 / kg.

[0020] Preferably, the specific surface area of the phosphorus slag powder is ≥350m 2 / kg.

[0021] The choice of cementitious materials will also have a significant impact on the mechanical properties of foamed concrete. In order to meet the sound insulation and mechanical properties of the sound barrier, the present invention needs to form a pore wall with good supporting capacity. After a large number of experiments, the present invention uses high-alumina cement as the main material, combined with silicate cement and desulfurized gypsum, and supplemented with phosphorus slag powder and modified zeolite powder. The main component of high-alumina cement is calcium aluminate with low alkalinity, which hydrates relatively quickly and produces aluminum gel. It basically does not produce Ca(OH)2 and has a dense structure. Desulfurized gypsum provides SO4 2-, it hydrates with calcium aluminate to form ettringite, and forms CSH gel and ettringite with the silicate mineral phase of silicate cement, supplementing the hydration products of high-alumina cement and overcoming the late strength shrinkage of cement stone caused by pure high-alumina cement. The addition of phosphorus slag powder can further reduce the Ca(OH)2 concentration in the hydration products. Modified zeolite powder also has a volcanic ash effect, and phosphorus slag powder and modified zeolite powder can adjust the cementitious material system to a reasonable viscosity, thereby improving the dispersion effect of steel fiber in foamed concrete. Experiments show that its use effect is better than admixtures such as fly ash and mineral powder.

[0022] Preferably, the steel fiber is a copper-plated hook-end steel fiber with a length of 5-12 mm. The addition of steel fiber can significantly increase the rigidity and toughness of concrete and improve the mechanical properties of concrete.

[0023] Preferably, the water reduction rate of the polycarboxylate water reducer is ≥25%.

[0024] Preferably, the lignin sulfonate is at least one of calcium lignin sulfonate, sodium lignin sulfonate, and magnesium lignin sulfonate.

[0025] In the present invention, lignin sulfonate has the dual effects of foaming and water reduction. Moreover, polycarboxylate water-reducing agent has a high water-reducing rate, but is sensitive to cement adaptability and easily causes slurry exudation and hardening. Lignin sulfonate is relatively more adaptable. In the present invention, the water-reducing component obtained by compounding polycarboxylate water-reducing agent and lignin sulfonate has good adaptability to the cementitious material system of the present invention. The prepared foamed concrete slurry has moderate viscosity, relatively uniform foam cells, good pore wall strength, and good dispersibility for steel fibers.

[0026] Preferably, the particle size of the millimeter-sized SAP particles is 1-2 mm. More preferably, the material of the SAP particles is sodium polyacrylate. The present invention utilizes the water absorption characteristics of millimeter-sized SAP particles as pore-forming agents. The millimeter-sized SAP particles absorb water and swell and are embedded in the concrete slurry. When the concrete hardens, the millimeter-sized SAP particles gradually release the absorbed water, shrink in volume to form holes. Compared with particles such as polystyrene particles, the pore diameter of the millimeter-sized SAP particles is more controllable. In addition, SAP particles are hydrophilic particles, while polystyrene particles and the like are hydrophobic particles. The pore wall strength of the SAP particles is better, and the water released by the SAP particles can achieve internal curing of the concrete slurry, further improving the mechanical properties. In addition, the SAP particles in the pore wall can also absorb sound waves, and the gap between the particles and the pore wall forms a wedge, which further reduces the penetration of sound waves and improves the sound insulation effect of the sound barrier.

[0027] Preferably, the calcination time is 1.5-2.5 hours. The calcination process can expel moisture from the zeolite powder structure, facilitating air entry and improving the gasification effect. The calcination process can also increase the activity of the zeolite powder, which is beneficial for subsequent hydration reactions. A reasonable calcination temperature is beneficial for moisture expulsion and activation. If the calcination temperature is too high, it is easy to cause the zeolite powder to form too much glass phase, causing pore blockage or collapse, affecting the gasification effect and activity. The calcination time should not be too long. Calcination time that is too long will not significantly improve the calcination effect and will also result in energy waste.

[0028] The present invention also relates to a method for preparing the foamed concrete sound barrier, which specifically comprises the following steps:

[0029] 1) Mix high alumina cement, silicate cement, desulfurized gypsum, phosphorus slag powder, modified zeolite powder and millimeter-sized SAP particles to obtain dry powder.

[0030] 2) Add polycarboxylate water reducer and lignin sulfonate into water to obtain an admixture aqueous solution,

[0031] 3) Pour the admixture aqueous solution into the dry powder and mix evenly to obtain a mixed slurry.

[0032] 4) Add steel fiber to the mixed slurry and stir evenly to obtain foamed concrete slurry.

[0033] 5) The foamed concrete slurry is molded and cured.

[0034] Preferably, the forming is performed by mold forming.

[0035] Preferably, the curing adopts standard curing, and more preferably, the curing is performed for 28 days.

[0036] Compared with the prior art, the present invention has the following technical advantages:

[0037] 1. The present invention adopts a gelling material system with a specific composition, which has good slurry viscosity, makes steel fibers easy to disperse, and has a short setting time, which is beneficial to mold turnover;

[0038] 2. The present invention uses a specific composition of gas-generating components, which is suitable for the cementitious material system, to form graded and interconnected pores;

[0039] 3. The present invention adopts a water-reducing component with a specific composition, which has good adaptability to cementitious materials, and the foamed concrete has high fluidity and good workability and can be molded;

[0040] 4. The present invention uses industrial solid waste to solve the environmental hazards caused by the storage of industrial solid waste and improve environmental benefits;

[0041] 5. The foamed concrete of the present invention adopts an active powder concrete system as a basis. The sound barrier prepared has good sound insulation effect and high mechanical properties, and can be directly installed without using a protective layer. DETAILED DESCRIPTION

[0042] In order to characterize the effect of the present invention, foamed concrete was prepared and its performance was tested. During the experiment, 42.5 high alumina cement, 52.5P·Ⅰ Portland cement, and phosphorus slag powder with a specific surface area of 400m 2 / kg, the steel fiber is a copper-plated end hook type steel fiber with a length of 5-12mm, the water reduction rate of the polycarboxylic acid water reducer is 28%, the lignin sulfonate is calcium lignin sulfonate, the millimeter-level SAP particle size is 1-2mm, and the modified zeolite powder modification process is: crush the zeolite powder to 0.1-0.3mm and calcined at 450℃ for 2h.

[0043] Example 1

[0044] The foamed concrete is composed of the following raw materials in parts by weight: 130 parts of high alumina cement, 120 parts of Portland cement, 40 parts of desulfurized gypsum, 60 parts of phosphorus slag powder, 90 parts of modified zeolite powder, 70 parts of steel fiber, 12 parts of polycarboxylate water reducer, 4 parts of lignin sulfonate, 5 parts of millimeter-sized SAP particles, and 110 parts of water.

[0045] After testing, the pouring time of foamed concrete is 3.9s, the final setting time is 6.2h, the 28d compressive strength is 65.6MPa, the 28d flexural strength is 8.9MPa, and the average sound absorption coefficient is 0.75.

[0046] Example 2

[0047] The foamed concrete is composed of the following raw materials in parts by weight: 160 parts of high-alumina cement, 100 parts of Portland cement, 45 parts of desulfurized gypsum, 60 parts of phosphorus slag powder, 90 parts of modified zeolite powder, 70 parts of steel fiber, 14 parts of polycarboxylate water reducer, 3 parts of lignin sulfonate, 6 parts of millimeter-sized SAP particles, and 110 parts of water.

[0048] After testing, the foamed concrete pouring time is 3.6s, the final setting time is 5.8h, the 28d compressive strength is 68.7MPa, the 28d flexural strength is 9.5MPa, and the average sound absorption coefficient is 0.79.

[0049] Comparative Example 1

[0050] The foamed concrete is composed of the following raw materials in parts by weight: 160 parts of 42.5 grade rapid hardening sulphoaluminate cement, 100 parts of Portland cement, 45 parts of fly ash, 60 parts of phosphorus slag powder, 90 parts of modified zeolite powder, 70 parts of steel fiber, 14 parts of polycarboxylate water reducer, 3 parts of lignin sulfonate, 6 parts of millimeter-sized SAP particles, and 110 parts of water.

[0051] After testing, the foamed concrete pouring time is 5.2s, the final setting time is 7.8h, the 28d compressive strength is 55.7MPa, the 28d flexural strength is 7.3MPa, and the average sound absorption coefficient is 0.53.

[0052] Comparative Example 2

[0053] The foamed concrete is composed of the following raw materials in parts by weight: 160 parts of high-alumina cement, 100 parts of Portland cement, 45 parts of fly ash, 60 parts of mineral powder, 90 parts of modified zeolite powder, 70 parts of steel fiber, 14 parts of polycarboxylate water reducer, 3 parts of lignin sulfonate, 6 parts of millimeter-sized SAP particles, and 110 parts of water.

[0054] After testing, the pouring time of foamed concrete was 6.3s, the final setting time was 6.9h, the slurry had slight bleeding, the steel fiber sank, the 28d compressive strength was 56.5MPa, the 28d flexural strength was 6.8MPa, and the average sound absorption coefficient was 0.50.

[0055] Comparative Example 3

[0056] The foamed concrete is composed of the following raw materials in parts by weight: 260 parts of 52.5 grade ordinary Portland cement, 45 parts of desulfurized gypsum, 60 parts of phosphorus slag powder, 90 parts of modified zeolite powder, 70 parts of steel fiber, 14 parts of polycarboxylate water reducer, 3 parts of lignin sulfonate, 6 parts of millimeter-sized SAP particles, and 110 parts of water.

[0057] After testing, it was found that foamed concrete had poor workability and could not be cast into shape.

[0058] Comparative Example 4

[0059] The foamed concrete is composed of the following raw materials in parts by weight: 160 parts of high-alumina cement, 100 parts of Portland cement, 45 parts of desulfurized gypsum, 60 parts of phosphorus slag powder, 6 parts of sodium dodecylbenzene sulfonate, 70 parts of steel fiber, 14 parts of polycarboxylate water reducer, 3 parts of lignin sulfonate, 6 parts of millimeter-sized SAP particles, and 110 parts of water.

[0060] After testing, it was found that the foamed concrete was segregated and compacted, there were a large number of bubbles on the surface of the slurry and they kept bursting, the steel fibers sank, and it was impossible to cast and form.

[0061] Comparative Example 5

[0062] The foamed concrete is composed of the following raw materials in parts by weight: 160 parts of high-alumina cement, 100 parts of Portland cement, 45 parts of desulfurized gypsum, 60 parts of phosphorus slag powder, 90 parts of zeolite powder, 70 parts of steel fiber, 17 parts of polycarboxylate water reducer, 6 parts of millimeter-sized SAP particles, and 110 parts of water.

[0063] After testing, the pouring time of foamed concrete is 6.4s, the slurry is relatively viscous, the final setting time is 6.3h, the 28d compressive strength is 55.7MPa, the 28d flexural strength is 7.2MPa, and the average sound absorption coefficient is 0.35.

[0064] Comparative Example 6

[0065] The foamed concrete is composed of the following raw materials in parts by weight: 160 parts of high-alumina cement, 100 parts of Portland cement, 45 parts of desulfurized gypsum, 60 parts of phosphorus slag powder, 90 parts of modified zeolite powder, 70 parts of steel fiber, 14 parts of polycarboxylate water reducer, 3 parts of lignin sulfonate, 6 parts of 1-2 mm ceramic sand particles, and 110 parts of water.

[0066] After testing, the pouring time of foamed concrete is 5.3s, the final setting time is 6.6h, the 28d compressive strength is 42.6MPa, the 28d flexural strength is 5.2MPa, and the average sound absorption coefficient is 0.53.

[0067] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A foamed concrete sound barrier, characterized in that: It is composed of the following raw materials in parts by weight: 100-180 parts of high alumina cement, 90-120 parts of Portland cement, 30-50 parts of desulfurized gypsum, 50-80 parts of phosphorus slag powder, 80-100 parts of modified zeolite powder, 60-80 parts of steel fiber, 10-15 parts of polycarboxylate water reducer, 2-5 parts of lignin sulfonate, 3-6 parts of millimeter-sized SAP particles, 100-120 parts water, The modification process of the modified zeolite powder is as follows: crushing the zeolite powder to 0.1-0.3 mm and calcining at 400-500°C.

2. The foamed concrete sound barrier according to claim 1, characterized in that: The strength grade of the high alumina cement is ≥42.

5.

3. The foamed concrete sound barrier according to claim 1, characterized in that: The silicate cement strength grade is ≥52.5, and the specific surface area is ≥320m 2 / kg.

4. The foamed concrete sound barrier according to claim 1, characterized in that: The specific surface area of the phosphorus slag powder is ≥350m 2 / kg.

5. The foamed concrete sound barrier according to claim 1, characterized in that: The steel fiber is a copper-plated hook-end steel fiber with a length of 5-12 mm.

6. The foamed concrete sound barrier according to claim 1, characterized in that: The water reducing rate of the polycarboxylate water reducer is ≥25%.

7. The foamed concrete sound barrier according to claim 1, characterized in that: The lignin sulfonate is at least one of calcium lignin sulfonate, sodium lignin sulfonate and magnesium lignin sulfonate.

8. The foamed concrete sound barrier according to claim 1, characterized in that: The millimeter-scale SAP particles have a particle size of 1-2 mm.

9. The foamed concrete sound barrier according to claim 1, characterized in that: The calcination time is 1.5-2.5h.

10. The method for preparing a foamed concrete sound barrier according to any one of claims 1 to 9, characterized in that: The steps include: 1) Mix high alumina cement, silicate cement, desulfurized gypsum, phosphorus slag powder, modified zeolite powder and millimeter-sized SAP particles to obtain dry powder. 2) Add polycarboxylate water reducer and lignin sulfonate into water to obtain an admixture aqueous solution, 3) Pour the admixture aqueous solution into the dry powder and mix evenly to obtain a mixed slurry. 4) Add steel fiber to the mixed slurry and stir evenly to obtain foamed concrete slurry. 5) The foamed concrete slurry is molded and cured.