Composition, concrete and method of preparation and use for the preparation of crack resistant and toughened foamed concrete

Abstract

The application relates to the field of building materials, and discloses a composition for preparing anti-cracking and toughening foam concrete, concrete, a preparation method and application. The composition contains the following components which are independently stored or stored in combination: Portland cement, fly ash, silica fume, redispersible emulsion powder, fiber material, foaming agent, water reducing agent and water. The foam concrete provided by the application has the advantages of good toughness, anti-cracking performance and high strength and is suitable for lining filling of tunnel engineering, mine and tunnel backfilling and road engineering.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of building materials, in particular, to a composition for preparing a crack-resistant toughened foam concrete, a concrete and a preparation method and application. BACKGROUND

[0002] Foam concrete, as a new energy-saving material, has been widely used in thermal insulation wall, pipeline backfill, retaining wall and other fields in recent years due to its own performance. However, foam concrete still has defects such as easy cracking, large shrinkage deformation, low strength and small toughness, which limits its application.

[0003] CN113493340A discloses a magnesium phosphate-based foam concrete thermal insulation material, which is composed of the following raw materials by weight: magnesium compound 60-90 parts, active foaming agent 1-8 parts, dense air entraining agent 0.1-0.3 parts, mineral admixture 20-35 parts, high-efficiency water reducing agent 0.5-1 part, composite retarder 5-15 parts, phosphate 20-30 parts, quartz sand 75-125 parts, water-resistant agent 0.5-2 parts, and pH stabilizer 5-8 parts. The magnesium phosphate-based foam concrete thermal insulation material has the characteristics of high early strength, good fluidity, uniform pores, excellent thermal resistance, easy construction, low toxicity, non-flammability, environmental protection and energy saving.

[0004] CN112679185A discloses a gypsum-based foam concrete and a preparation method thereof. The gypsum-based foam concrete comprises, by weight fraction, gypsum 50-65 parts, Portland cement 22-28 parts, sulphoaluminate cement 1-2 parts, quicklime and / or slaked lime 1-2 parts, fly ash 13-18 parts, Si0, aerogel 4-8 parts, graphene oxide 0.2-0.4 parts, water reducing agent 0.2-0.4 parts, waterproofing agent 0.05-0.1 parts, and foaming agent 0.09-0.2 parts. The components play a synergistic role under a specific ratio, which can significantly improve the water resistance of the gypsum-based foam concrete and significantly reduce the water absorption rate of the gypsum-based foam concrete.

[0005] CN113511873A discloses a preparation method of high-strength foam lightweight concrete. The preparation method comprises the following components by weight fraction: titanium gypsum powder 50-55 parts, slag powder 18-22 parts, Portland cement 20-25 parts, foam stabilizer 1-1.5 parts, cement foaming agent 1-1.5 parts, water reducing agent 0.5-0.8 parts, nitrogen-doped silicon dioxide 0.8-1.2 parts, and nano zinc oxide powder 0.5-0.8 parts. The prior art accurately controls the addition amount of water, titanium gypsum powder, slag powder and Portland cement by using a calculation formula, thereby accurately controlling the wet bulk density of the slurry, greatly reducing the open porosity of the foamed concrete, and improving the strength and impermeability of the foamed concrete.

[0006] However, these prior arts do not study the cracking performance and toughness of the foamed concrete. SUMMARY

[0007] The present application aims to overcome the defects of the prior foamed concrete, such as easy cracking, low strength, and small toughness, and to provide a foamed concrete with good toughness, anti-cracking, and good mechanical properties.

[0008] To achieve the above-mentioned purpose, the first aspect of the present application provides a composition for preparing a cracking-resistant and toughening foamed concrete, which contains the following components stored independently or in combination of two or more:

[0009] portland cement, fly ash, silica fume, redispersible latex powder, fiber material, foaming agent, water reducing agent, water;

[0010] In the composition, the content of the portland cement is 84-107 parts by weight, the content of the fly ash is 14-44 parts by weight, the content of the silica fume is 25-32 parts by weight, the content of the redispersible latex powder is 0.2-0.4 parts by weight, the content of the fiber material is 0.22-0.33 parts by weight, the content of the foaming agent is 1.6-3.2 parts by weight, the content of the water reducing agent is 0.42-1 parts by weight, and the content of the water is 69-92 parts by weight.

[0011] The fiber material is a combination of nylon-based synthetic fiber and polyvinyl alcohol fiber, and the content ratio of the nylon-based synthetic fiber to the polyvinyl alcohol fiber is 1:0.8-1.8.

[0012] The second aspect of the present application provides a method for preparing a cracking-resistant and toughening foamed concrete, which uses the composition described in the first aspect, and comprises:

[0013] (1) first mixing the water reducing agent with water to obtain a mixture I;

[0014] (2) second mixing the mixture I with component A to obtain a mixture II; the component A contains portland cement, fly ash, and silica fume;

[0015] (3) third mixing the mixture II with component B to obtain a mixture III; the component B contains a foaming agent;

[0016] (4) fourth mixing the mixture III with component C to obtain the cracking-resistant and toughening foamed concrete; the component C contains redispersible latex powder and fiber material.

[0017] The third aspect of the present application provides a cracking-resistant and toughening foamed concrete prepared by the method described in the second aspect.

[0018] The fourth aspect of the present application provides an application of the crack-resistant and toughened foam concrete in road and tunnel engineering.

[0019] The present application makes full use of the "ball effect" of fly ash by controlling the amount of fly ash to improve the workability of the foam concrete, and makes the micro aggregate filling effect of silica fume to be maximized by controlling the amount of silica fume, so as to further improve the mechanical properties of the foam concrete. Meanwhile, the present application also improves the internal structure of the foam concrete by adding a specific amount of redispersible latex powder to generate a polymer network film structure, so as to improve the toughness of the foam concrete. The present application further improves the toughness of the foam concrete by using a specific ratio of nylon-based synthetic fiber and polyvinyl alcohol fiber, and cooperates with a specific amount of other components to obtain a foam concrete with good toughness, crack resistance and high strength and other advantages. DETAILED DESCRIPTION

[0020] The endpoints of the ranges and any values disclosed herein are not limited to the precise values recited as the exact dimensions are not critical to the present application. Any numerical value, however, can be expressed as a range by either adding or subtracting a small percentage (e.g., 1-10 percent) from the stated value to account for variations, measurement inaccuracies, and the like. For numerical ranges expressed in the format "from x to y," "x is about y," or "x to y is about z," it will be understood that the numerical values are each a separate endpoint.

[0021] It should be noted that the loss on ignition in the present application refers to the percentage of weight loss of the raw material dried at 105-110℃ after being burned at 1000-1100℃.

[0022] As described above, the first aspect of the present application provides a composition for preparing a crack-resistant and toughened foam concrete, which contains the following components stored independently or in combination of two or more:

[0023] portland cement, fly ash, silica fume, redispersible latex powder, fiber material, foaming agent, water reducing agent, water;

[0024] In the composition, the content of the portland cement is 84-107 parts by weight, the content of the fly ash is 14-44 parts by weight, the content of the silica fume is 25-32 parts by weight, the content of the redispersible latex powder is 0.2-0.4 parts by weight, the content of the fiber material is 0.22-0.33 parts by weight, the content of the foaming agent is 1.6-3.2 parts by weight, the content of the water reducing agent is 0.42-1 parts by weight, and the content of the water is 69-92 parts by weight;

[0025] The fiber material is a combination of nylon-based synthetic fiber and polyvinyl alcohol fiber, and the content weight ratio of the nylon-based synthetic fiber and the polyvinyl alcohol fiber is 1:0.8-1.8.

[0026] Preferably, the Portland cement is selected from at least one of P.O 42.5 ordinary Portland cement, P.O 52.5R Portland cement.

[0027] Preferably, the average particle size of the fly ash is 30-45 µm, the density is 2.0-2.4 g / cm 3 , the loss on ignition is 8.5-10.94%. The inventors of the present application found that the foamed concrete obtained in this preferred case has higher compressive strength and flexural strength.

[0028] Preferably, the average particle size of the silica fume is 0.15-0.25 µm, the density is 2.1-2.3 g / cm 3 , the silicon dioxide content is 85.2-93.7 wt%, and the specific surface area is 15000-26500 m 2 / kg.

[0029] Preferably, the average particle size of the redispersible latex powder is 1-10 µm.

[0030] Preferably, the redispersible latex powder is selected from at least one of styrene-acrylic latex powder, pure acrylic latex powder, and EVA latex powder. More preferably, the redispersible latex powder is EVA latex powder.

[0031] Preferably, the average length of the nylon-based synthetic fiber is 4-8 mm, and the average diameter is 15-20 µm. The inventors of the present application found that the foamed concrete obtained in this preferred case has better toughness.

[0032] Preferably, the average length of the polyvinyl alcohol fiber is 6-12 mm, and the average diameter is 18-24 µm.

[0033] Preferably, the foaming agent is a rosin-based foaming agent. Exemplarily, the rosin-based foaming agent can be HTW-I composite foaming agent available from Henan Huatai New Material Science and Technology Co., Ltd.

[0034] Preferably, the water reducing agent is selected from at least one of polycarboxylic acid water reducing agent. Exemplarily, the polycarboxylic acid water reducing agent can be at least one of PC-1009 powdery polycarboxylic acid water reducing agent available from Wuhan Huaxuan High-tech Co., Ltd., XHY-006 polycarboxylic acid water reducing agent available from Shandong Xihongyue Chemical Co., Ltd., and Sika 540P polycarboxylic acid water reducing agent available from Nanjing Yaojie Energy-saving Technology Co., Ltd.

[0035] The method for preparing the crack-resistant and toughened foam concrete is not particularly limited in the present application, and can be selected according to the technical means known in the art by those skilled in the art. However, in order to obtain the crack-resistant and toughened foam concrete which is easier to construct, the present application provides a preferred embodiment. As described above, the second aspect of the present application provides a method for preparing the crack-resistant and toughened foam concrete, which is performed by using the composition described in the aforementioned first aspect, comprising:

[0036] (1) first mixing a water reducing agent with water to obtain a mixture I;

[0037] (2) second mixing the mixture I with a component A to obtain a mixture II; the component A contains Portland cement, fly ash and silica fume;

[0038] (3) third mixing the mixture II with a component B to obtain a mixture III; the component B contains a foaming agent;

[0039] (4) fourth mixing the mixture III with a component C to obtain the crack-resistant and toughened foam concrete; the component C contains a redispersible latex powder and a fibrous material.

[0040] Preferably, in step (1), the first mixing is performed under stirring at a speed of 60-70 rpm and a temperature of 20-40°C for 1-2 min.

[0041] Preferably, in step (2), the second mixing is performed under stirring at a speed of 2500-3000 rpm and a temperature of 20-40°C for 2-3 min.

[0042] According to a preferred embodiment, in step (3), the third mixing is performed under stirring at a speed of 2800-3000 rpm and a temperature of 20-40°C for 2-3 min.

[0043] According to another preferred embodiment, in step (4), the fourth mixing is performed under stirring at a speed of 2500-3000 rpm and a temperature of 20-40°C for 1-2 min.

[0044] As described above, the third aspect of the present application provides the crack-resistant and toughened foam concrete prepared by the method described in the aforementioned second aspect.

[0045] As described above, the fourth aspect of the present application provides the use of the crack-resistant and toughened foam concrete described in the aforementioned third aspect in road and tunnel engineering.

[0046] The present application will be described in detail below by way of examples.

[0047] In the following examples, the raw materials used are commercially available, unless otherwise specified.

[0048] In the present application, the room temperature means 25±2℃, and the crack resistance and toughening foam concrete in the following examples are all carried out at room temperature, unless otherwise specified.

[0049] In the present application, every weight part means 10g, unless otherwise specified.

[0050] Silicate cement: P.O 42.5 ordinary silicate cement (hereinafter referred to as P.O 42.5), purchased from Pingyin Mountain Water Cement Co., Ltd.

[0051] Fly ash I: purchased from Henan Hengyuan New Material Co., Ltd., with an average particle size of 40 µm and a density of 2.2 g / cm 3 , a loss on ignition of 10.94%.

[0052] Fly ash II: purchased from Henan Hengyuan New Material Co., Ltd., with an average particle size of 70 µm and a density of 2.4 g / cm 3 , a loss on ignition of 8.50%.

[0053] Silica fume: purchased from Henan Hengyuan New Material Co., Ltd., with an average particle size of 0.20 µm and a density of 2.2 g / cm 3 , a silica content of 93.7 wt%, and a specific surface area of 26500 m 2 / kg.

[0054] Redispersible latex powder: EVA latex powder, with a brand name of SWF-01, purchased from Shenzhen Boshun Chemical Co., Ltd., with an average particle size of 5 µm.

[0055] Fiber material:

[0056] Nylon-based synthetic fiber I (hereinafter referred to as nylon fiber I): purchased from Shenzhen Telai New Material Technology Co., Ltd., with an average length of 4 mm and an average diameter of 15 µm.

[0057] Nylon-based synthetic fiber II (hereinafter referred to as nylon fiber II): purchased from Shenzhen Telai New Material Technology Co., Ltd., with an average length of 10 mm and an average diameter of 20 µm.

[0058] Polyvinyl alcohol fiber: purchased from Shenzhen Telai New Material Technology Co., Ltd., with an average length of 6 mm and an average diameter of 22 µm.

[0059] Glass fiber: purchased from Zibo Taixin Composite Material Co., Ltd., average length of 6 mm, average diameter of 22 pm.

[0060] Foaming agent: rosin-based foaming agent, brand HTW-I, purchased from Henan Huatai New Material Science and Technology Co., Ltd.

[0061] Water reducing agent: polycarboxylic acid water reducing agent, brand PC-1009, purchased from Wuhan Huaxuan High-tech Co., Ltd.

[0062] Water: deionized water.

[0063] Example 1

[0064] This example is used to illustrate that the composition for preparing the crack-resistant and toughened foam concrete according to the present application is prepared according to the formulation and process parameters in Table 1, and the foam concrete is prepared by the method as follows.

[0065] The method for preparing the foam concrete comprises the following steps:

[0066] (1) At room temperature, the water reducing agent and water are stirred at a speed of 60 rpm for 2 min to obtain a mixture I;

[0067] (2) At room temperature, the mixture I and the Portland cement, fly ash and silica fume in component A are stirred at a speed of 3000 rpm for 2 min to obtain a mixture II;

[0068] (3) At room temperature, the mixture II and the foaming agent in component B are stirred at a speed of 3000 rpm for 3 min to obtain a mixture III;

[0069] (4) At room temperature, the mixture III and the redispersible latex powder and fiber material in component C are stirred at a speed of 2500 rpm for 2 min to obtain the crack-resistant and toughened foam concrete H1.

[0070] Examples 2-5

[0071] Examples 2-5 are carried out by using the same flow as Example 1, except that the formulation and process parameters of the composition for preparing the crack-resistant and toughened foam concrete are different, which are shown in Table 1.

[0072] The foam concrete H2, foam concrete H3, foam concrete H4 and foam concrete H5 are prepared.

[0073] Example 6

[0074] This example adopts the similar formula and method of Example 1 to prepare the foamed concrete, the difference is: the same weight of fly ash II instead of fly ash I, the rest of the conditions are the same as Example 1, to prepare the foamed concrete H6, see Table 1.

[0075] Example 7

[0076] This example adopts the similar formula and method of Example 1 to prepare the foamed concrete, the difference is: the same weight of nylon fiber II instead of nylon fiber I, the rest of the conditions are the same as Example 1, to prepare the foamed concrete H7, see Table 1.

[0077] Comparative Example 1

[0078] This example adopts the similar formula and method of Example 1 to prepare the foamed concrete, the difference is: no fiber material is used, the rest of the conditions are the same as Example 1, to prepare the foamed concrete DH1, see Table 1.

[0079] Comparative Example 2

[0080] This example adopts the similar formula and method of Example 1 to prepare the foamed concrete, the difference is: no silica fume is used, the rest of the conditions are the same as Example 1, to prepare the foamed concrete DH2, see Table 1.

[0081] Comparative Example 3

[0082] This example adopts the similar formula and method of Example 1 to prepare the foamed concrete, the difference is: the weight ratio of nylon-based synthetic fiber I and polyvinyl alcohol fiber is 1:3, the rest of the conditions are the same as Example 1, to prepare the foamed concrete DH3, see Table 1.

[0083] Comparative Example 4

[0084] This example adopts the similar formula and method of Example 1 to prepare the foamed concrete, the difference is: the same weight of polyvinyl alcohol fiber is replaced by glass fiber, the rest of the conditions are the same as Example 1, to prepare the foamed concrete DH4, see Table 1.

[0085] Table 1

[0086]

[0087] Table 1 (continued)

[0088]

[0089] Test Example 1

[0090] The crack resistance and toughening foam concrete prepared from the examples and comparative examples was tested according to the following method, and the specific test results are shown in Table 2.

[0091] (1) Compressive strength test: According to the standard JG-T-266-2011 "Foam concrete", 100mmx100mmx100mm size test pieces were used, 3 test pieces were made for each group, standard curing was carried out, and after reaching the age (i.e. after 28 days) the compressive strength test was carried out.

[0092] (2) Flexural strength test: According to the standard GB / T17671-199 "Cement mortar strength test method (ISO method)", 40mmx40mmx160mm size test pieces were used, 3 test pieces were made for each group, standard curing was carried out, and after reaching the age (i.e. after 28 days) the flexural strength test was carried out.

[0093] (3) Three-point bending toughness index I5 test: According to the standard "ASTM C1018-97", 40mmx40mmx160mm size test pieces were used, 3 test pieces were made for each group, standard curing was carried out, and after reaching the age (i.e. after 28 days) the three-point bending test was carried out.

[0094] (4) Anti-cracking performance test: The earliest cracking time of the foam concrete was determined by using an oval ring constraint shrinkage cracking test instrument, and the size of the oval ring used in the test was: the inner size was 210mmx90mmx45mm, and the outer size was 250mmx130mmx45mm.

[0095] (5) Dry density test: A group of test pieces were taken, the length, width and height of the test pieces were measured block by block, 1 time at each end and middle, and 1 time on the opposite surface, a total of 6 times, and the average value was taken, the result was accurate to 1mm, and the volume V of each test piece was calculated.

[0096] The test pieces were placed in a drying oven at a temperature of (60±5)℃ and dried until the mass difference between the two times was not more than 1g, the test pieces were taken out, and then the test pieces were placed in a desiccator and cooled to room temperature, and then the mass m0 of the dried test pieces was measured, accurate to 1g, and the dry density p0=m0 / V.

[0097] Table 2

[0098]

[0099] As can be seen from the results in Table 2, the foam concrete prepared by using the composition provided by the application has excellent compressive strength, flexural strength, toughness and anti-cracking performance.

[0100] The preferred embodiments of the present application are described in detail above, but the present application is not limited thereto. Within the technical concept of the present application, various simple modifications can be made to the technical solutions of the present application, including that each technical feature is combined in any other suitable manner. These simple modifications and combinations should also be considered as disclosed by the present application and fall within the protection scope of the present application.

Claims

1. A composition for making a crack resistant, toughened foam concrete, characterized in that, The composition contains the following components which are independently stored or mixed together: portland cement, fly ash, silica fume, redispersible emulsion powder, fibrous material, foaming agent, water reducing agent, water; In the composition, the content of the portland cement is 84-107 parts by weight, the content of the fly ash is 14-44 parts by weight, the content of the silica fume is 25-32 parts by weight, the content of the redispersible emulsion powder is 0.2-0.4 parts by weight, the content of the fibrous material is 0.22-0.33 parts by weight, the content of the foaming agent is 1.6-3.2 parts by weight, the content of the water reducing agent is 0.42-1 parts by weight, and the content of the water is 69-92 parts by weight; The fibrous material is a combination of nylon-based synthetic fiber and polyvinyl alcohol fiber, and the content weight ratio of the nylon-based synthetic fiber to the polyvinyl alcohol fiber is 1:0.8-1.8; the average length of the nylon-based synthetic fiber is 4-8 mm, and the average diameter is 15-20 µm; the average length of the polyvinyl alcohol fiber is 6-12 mm, and the average diameter is 18-24 µm.

2. The composition of claim 1, wherein, The portland cement is selected from at least one of P.O 42.5 ordinary portland cement and P.O 52.5R portland cement; and / or, The average particle size of the fly ash is 30-45 pm, the density is 2.0-2.4 g / cm 3 , the loss on ignition is 8.5-10.94%; and / or, The silica fume has an average particle size of 0.15-0.25 pm, a density of 2.1-2.3 g / cm 3 , a silica content of 85.2-93.7 wt%, and a specific surface area of 15000-26500 m 2 / kg.

3. The composition according to claim 1 or 2, wherein, The redispersible emulsion powder is selected from at least one of styrene-acrylic emulsion powder, pure acrylic emulsion powder, and EVA emulsion powder.

4. The composition of claim 1 or 2, wherein, The foaming agent is a rosin-based foaming agent; and / or The water reducing agent is a polycarboxylic acid water reducing agent.

5. A method of making a crack resistant, toughened foam concrete, characterised in that, The method is applied to the composition of any one of claims 1-4, comprising: (1) mixing the water reducing agent with water to obtain a mixture I; (2) mixing the mixture I with component A to obtain a mixture II; the component A contains portland cement, fly ash, and silica fume; (3) mixing the mixture II with component B to obtain a mixture III; the component B contains a foaming agent; (4) mixing the mixture III with component C to obtain the crack-resistant and toughened foam concrete; the component C contains redispersible emulsion powder and fibrous material.

6. The method of claim 5, wherein, In step (1), the first mixing is performed under stirring at a speed of 60-70 rpm and a temperature of 20-40 °C for 1-2 min; and / or; In step (2), the second mixing is performed under stirring at a speed of 2500-3000 rpm and a temperature of 20-40 °C for 2-3 min.

7. The method of claim 5 or 6, wherein, In step (3), the third mixing is performed under stirring at a speed of 2800-3000 rpm and a temperature of 20-40 °C for 2-3 min.

8. The method of claim 5 or 6, wherein, In step (4), the fourth mixing is performed under stirring at a speed of 2500-3000 rpm and a temperature of 20-40 °C for 1-2 min.

9. The crack-resistant and toughened foam concrete prepared by the method of any one of claims 5-8.

10. Use of the split-resistant, toughened foam concrete according to claim 9 in road and tunnel engineering.

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