Foam concrete nano foaming agent and application thereof

Abstract

The invention discloses a foam concrete nano foaming agent and application thereof, and belongs to the technical field of concrete materials. The foam concrete nano foaming agent is composed of the following components in percentage by mass: 10-50% of cellulose; 10%-50% of a water-soluble polymer material; 5%-30% of a surfactant; and 5%-30% of nanoparticles. The foam concrete nano foaming agent provided by the invention has the advantages of low cost and good foaming effect. Nano foam generated by foaming of the foaming agent is high in stability, and when the foaming agent is applied to preparation of a foam concrete material, the foam concrete is wide in dry density range and low in collapse rate, has good mechanical properties, flowing properties, dry shrinkage properties, stability and heat insulation properties, and is wide in application prospect. The method is suitable for the fields of building materials, housing construction, road and bridge engineering, cast-in-place backfill engineering, pit goaf backfill, garbage burying and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of concrete materials, and particularly relates to a foam concrete nano foaming agent and application thereof. Background Art

[0002] Foamed concrete is a new type of lightweight thermal insulation material that contains a large number of closed pores. The general method of generating pores is to use a foaming agent to generate foam, and then add the foam to the cement slurry. The quality of the foam produced by the foaming agent is an important factor affecting the performance of foamed concrete.

[0003] In the prior art, there are foaming agent products made of various surfactants and nanoparticles. However, the current foaming agents still have low foaming multiples (less than 15), small foam volume (the volume ratio of foam to foaming agent is about 300 to 500 times), unstable foam quality, and the performance of the foamed concrete is still not as good as expected. The production cost of the foaming agent is also an important factor affecting the promotion and large-scale application of foamed concrete. Therefore, it is necessary to develop a foamed concrete foaming agent with low cost, good foaming effect and stable quality, and use the foam produced by it to prepare foamed concrete with better performance. Summary of the invention

[0004] The present invention aims to solve at least one of the above-mentioned technical problems existing in the foam concrete foaming agent in the prior art. To this end, one of the purposes of the present invention is to provide a foam concrete nano foaming agent, the second purpose of the present invention is to provide a foam concrete nano foaming composition, the third purpose of the present invention is to provide a foam concrete, the fourth purpose of the present invention is to provide a method for preparing the foam concrete, and the fifth purpose of the present invention is to provide the application of the foam concrete.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] The first aspect of the present invention provides a foam concrete nano foaming agent, which is composed of the following components in percentage by mass:

[0007]

[0008] The cellulose is at least one of hydroxyethyl cellulose, hydroxypropyl methyl cellulose, cellulose acetate butyrate, and microcrystalline cellulose;

[0009] The water-soluble polymer material is at least one of polyacrylamide, sodium polyacrylate, polyvinyl alcohol, polyethyleneimine and polyvinyl pyrrolidone.

[0010] In order to increase the surface tension of the foam, the present invention proposes a foaming system composed of cellulose, a water-soluble polymer material, a surfactant and nanoparticles by considering the ionic effect and the Zeta potential. By using these components for foaming, a stable nano foam can be obtained, and it has the advantages of high foaming efficiency, large output foam volume and low production cost.

[0011] According to some embodiments of the foam concrete nano foaming agent component of the present invention, the cellulose is one of hydroxyethyl cellulose and hydroxypropyl methyl cellulose or a combination thereof.

[0012] According to some embodiments of the foam concrete nano foaming agent component of the present invention, the mass percentage of the cellulose is 20% to 40%.

[0013] According to some embodiments of the foam concrete nano foaming agent component of the present invention, the water-soluble polymer material is one of polyvinyl alcohol and polyethyleneimine or a combination thereof.

[0014] According to some embodiments of the foam concrete nano foaming agent component of the present invention, the mass percentage of the water-soluble polymer material is 20% to 40%.

[0015] According to some embodiments of the foam concrete nano foaming agent component of the present invention, the surfactant is at least one of a sulfate surfactant, a sulfonate surfactant, and a fatty alcohol polyoxyethylene ether.

[0016] According to some embodiments of the foam concrete nano foaming agent component of the present invention, the surfactant is at least one of sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, AEO-7, and AEO-9.

[0017] According to some other embodiments of the foam concrete nano foaming agent component of the present invention, the surfactant is one of sodium dodecyl sulfate and sodium dodecylbenzene sulfonate or a combination thereof.

[0018] According to some embodiments of the foam concrete nano foaming agent component of the present invention, the mass percentage of the surfactant is 5% to 20%.

[0019] According to some embodiments of the nano foaming agent component of the foamed concrete of the present invention, the nano particles are at least one of nano silicon dioxide, nano titanium dioxide, nano aluminum oxide, and nano calcium carbonate.

[0020] According to some embodiments of the foam concrete nano foaming agent component of the present invention, the nano particles are one of nano alumina and nano silicon dioxide or a combination thereof.

[0021] According to some embodiments of the foam concrete nano foaming agent component of the present invention, the mass percentage of the nano particles is 5% to 25%.

[0022] According to some embodiments of the foam concrete nano foaming agent of the present invention, it is composed of the following components in percentage by mass:

[0023]

[0024] According to some embodiments of the foam concrete nano foaming agent of the present invention, it is composed of the following components in percentage by mass: 20% to 40% hydroxypropyl methylcellulose, 20% to 40% polyvinyl alcohol, 5% to 20% sodium lauryl sulfate, and 5% to 25% nano alumina.

[0025] According to some embodiments of the foamed concrete nano foaming agent of the present invention, the volume ratio of the foamed concrete nano foaming agent to the nano foam produced by the foaming agent is 1:(3600-12000). In some specific embodiments, the volume ratio of the foamed concrete nano foaming agent to the nano foam produced by the foaming agent can be selected from 1:4000, 1:4500, 1:5000, 1:6000, 1:7000, 1:8000, 1:9000, 1:10000 or 1:11000.

[0026] According to some embodiments of the foam concrete nano-foaming agent of the present invention, the volume ratio of the foam concrete nano-foaming agent to the nano-foam produced by the foaming agent is 1:(4500-12000).

[0027] According to other embodiments of the foam concrete nano-foaming agent of the present invention, the volume ratio of the foam concrete nano-foaming agent to the nano-foam produced by the foaming agent is 1:(6000-9000).

[0028] When preparing the foam concrete nano foaming agent, all components need to be mixed.

[0029] The second aspect of the present invention provides a foamed concrete nano-foaming composition, comprising the foamed concrete nano-foaming agent described in the first aspect of the present invention and water; the mass ratio of the foamed concrete nano-foaming agent to water is 1: (200-500).

[0030] According to some embodiments of the foamed concrete nano-foaming composition of the present invention, the mass ratio of the foamed concrete nano-foaming agent to water is 1:(250-400). In some specific embodiments, the mass ratio of the foamed concrete nano-foaming agent to water can be selected from 300, 350 or 400.

[0031] According to some embodiments of the foamed concrete nano-foamed composition of the present invention, the foaming multiple of the foamed concrete nano-foamed composition is 15 to 40. In some specific embodiments, the foaming multiple can be selected from 20, 25, 30 or 35.

[0032] According to some embodiments of the foamed concrete nano-foaming composition of the present invention, the foaming multiple of the foamed concrete nano-foaming composition is 20-30.

[0033] When preparing the foamed concrete nano-foaming composition, the foamed concrete nano-foaming agent is mixed with water.

[0034] According to some embodiments of the foamed concrete nano-foaming composition of the present invention, the foamed concrete nano-foaming composition exists in the form of a solution.

[0035] The third aspect of the present invention provides a foamed concrete comprising the following components:

[0036] cement-based mixes and nanofoams;

[0037] The cement-based mixture includes cement and water;

[0038] The nano foam is prepared by foaming the foam concrete nano foam composition described in the second aspect of the present invention;

[0039] The mass ratio of the cement to the water is 1:(0.3-0.6);

[0040] The ratio of the cement to the nano foam is 1kg:(0.5-4)L.

[0041] According to some embodiments of the foamed concrete of the present invention, the mass ratio of the cement to the water is 1:(0.4-0.55).

[0042] According to some embodiments of the foamed concrete of the present invention, the ratio of the cement to the nano foam is 1 kg: (0.6-3) L.

[0043] According to some embodiments of the foamed concrete of the present invention, the cement includes at least one of ordinary Portland cement, Portland cement, and slag Portland cement.

[0044] According to some embodiments of the foamed concrete of the present invention, the strength grade of the cement is 42.5 or 52.5.

[0045] According to some embodiments of the foamed concrete of the present invention, the cement-based mixture further comprises at least one of the following components: rubber powder, cellulose, polypropylene fiber, ceramsite, sand, slag, fly ash, glass beads, and a water reducing agent.

[0046] According to some embodiments of the foamed concrete of the present invention, the cement-based mixture further comprises at least one of the following components: rubber powder, cellulose, polypropylene fiber, ceramsite, sand, slag, and a water reducing agent.

[0047] In some specific embodiments of the present invention, the cement-based mixture further includes rubber powder, cellulose, polypropylene fiber, ceramsite, sand, slag and a water reducing agent.

[0048] According to some embodiments of the foamed concrete of the present invention, when the cement-based mixture includes rubber powder, the mass of the rubber powder is 0.05% to 0.2% of the mass of the cement.

[0049] According to some embodiments of the foamed concrete of the present invention, when the cement-based mixture includes rubber powder, the mass of the rubber powder is 0.1% to 0.2% of the mass of the cement.

[0050] According to some embodiments of the foamed concrete of the present invention, when the cement-based mixture includes cellulose, the mass of the cellulose is 0.1% to 0.3% of the mass of the cement.

[0051] According to some embodiments of the foamed concrete of the present invention, when the cement-based mixture includes cellulose, the mass of the cellulose is 0.15% to 0.25% of the mass of the cement.

[0052] According to some embodiments of the foamed concrete of the present invention, in the cement-based mixture, the type of cellulose can be selected from the type of cellulose in the foamed concrete nano foaming agent of the first aspect of the present invention.

[0053] According to some embodiments of the foamed concrete of the present invention, when the cement-based mixture includes polypropylene fibers, the mass of the polypropylene fibers is 0.05% to 0.2% of the mass of the cement.

[0054] According to some embodiments of the foamed concrete of the present invention, when the cement-based mixture includes polypropylene fibers, the mass of the polypropylene fibers is 0.07% to 0.1% of the mass of the cement.

[0055] According to some embodiments of the foamed concrete of the present invention, when the cement-based mixture includes ceramsite, the mass of the ceramsite is 40% to 70% of the mass of the cement.

[0056] According to some embodiments of the foamed concrete of the present invention, when the cement-based mixture includes ceramsite, the mass of the ceramsite is 50% to 60% of the mass of the cement.

[0057] According to some embodiments of the foamed concrete of the present invention, when the cement-based mixture includes sand, the mass of the sand is 20% to 35% of the mass of the cement.

[0058] According to some embodiments of the foamed concrete of the present invention, when the cement-based mixture includes sand, the mass of the sand is 25% to 30% of the mass of the cement.

[0059] According to some embodiments of the foamed concrete of the present invention, the sand is selected from at least one of river sand, mountain sand, sea sand and artificial sand.

[0060] According to some embodiments of the foamed concrete of the present invention, when the cement-based mixture includes slag, the mass of the slag is 40% to 60% of the mass of the cement.

[0061] According to some embodiments of the foamed concrete of the present invention, when the cement-based mixture includes slag, the mass of the slag is 45% to 55% of the mass of the cement.

[0062] According to some embodiments of the foamed concrete of the present invention, when the cement-based mixture includes a water reducing agent, the mass of the water reducing agent is 0.5% to 3% of the mass of the cement.

[0063] According to some embodiments of the foamed concrete of the present invention, when the cement-based mixture includes a water reducing agent, the mass of the water reducing agent is 1.5% to 2% of the mass of the cement.

[0064] According to some embodiments of the foamed concrete of the present invention, the water reducer includes at least one of a lignin sulfonate water reducer, a naphthalene water reducer, a melamine water reducer, an aminosulfonate water reducer, a fatty acid water reducer, and a polycarboxylic acid water reducer.

[0065] According to some embodiments of the foamed concrete of the present invention, the cement-based mixture is composed of the following components: cement, rubber powder, cellulose, polypropylene fiber, ceramsite, sand, slag, fly ash, glass beads, water reducing agent and water.

[0066] According to some embodiments of the foamed concrete of the present invention, the wet density of the foamed concrete is 300 kg / m 3 ~1600kg / m 3 The wet density mentioned here refers to the density of the newly made foamed concrete slurry.

[0067] According to some embodiments of the foamed concrete of the present invention, the dry density of the foamed concrete is 180 kg / m 3 ~1500kg / m 3 .

[0068] According to some embodiments of the foamed concrete of the present invention, the 3-day compressive strength of the foamed concrete is 0.1 MPa to 20 MPa.

[0069] According to some embodiments of the foamed concrete of the present invention, the 7-day compressive strength of the foamed concrete is 0.3 MPa to 28 MPa.

[0070] According to some embodiments of the foamed concrete of the present invention, the 14-day compressive strength of the foamed concrete is 0.5 MPa to 32 MPa.

[0071] According to some embodiments of the foamed concrete of the present invention, the 28-day compressive strength of the foamed concrete is 0.6 MPa to 40 MPa.

[0072] According to some embodiments of the foamed concrete of the present invention, the slurry fluidity of the foamed concrete is 190 mm to 270 mm.

[0073] According to some embodiments of the foamed concrete of the present invention, a 14-day drying shrinkage value of the foamed concrete is 1.5 mm / m to 5 mm / m.

[0074] According to some embodiments of the foamed concrete of the present invention, a 90-day drying shrinkage value of the foamed concrete is 2 mm / m to 7 mm / m.

[0075] According to some embodiments of the foamed concrete of the present invention, after being tested for 40 freeze-thaw cycles, the mass loss rate of the foamed concrete is 1.5% to 3%.

[0076] According to some embodiments of the foamed concrete of the present invention, after being tested for 40 freeze-thaw cycles, the compressive strength loss rate of the foamed concrete is 10% to 18%.

[0077] According to some embodiments of the foamed concrete of the present invention, the collapse rate of the foamed concrete slurry after being placed for 24 hours is ≤0.1%.

[0078] The fourth aspect of the present invention provides a method for preparing the foamed concrete according to the third aspect of the present invention, comprising the following steps:

[0079] The foamed concrete nano-foam composition is foamed by a foaming machine to obtain nano-foam;

[0080] Mixing cement and water to obtain cement slurry;

[0081] The cement slurry is mixed with the nano foam to obtain the foamed concrete.

[0082] According to some embodiments of the method for preparing foamed concrete of the present invention, the foamed concrete nano-foaming composition is prepared by mixing a foamed concrete nano-foaming agent and water in a certain proportion.

[0083] According to some embodiments of the method for preparing foamed concrete of the present invention, in the step of foaming the foamed concrete nano-foamed composition through a foaming machine, the specific method of foaming is: injecting the foamed concrete nano-foamed composition into the foaming machine, adjusting the air pressure and water pressure, and producing nano-foam.

[0084] According to some embodiments of the method for preparing foamed concrete of the present invention, in the foaming step, the foaming machine is equipped with a frequency converter for adjusting air pressure and water pressure.

[0085] According to some embodiments of the method for preparing foamed concrete of the present invention, in the step of foaming the foamed concrete nano-foamed composition through a foaming machine, the volume ratio of the foamed concrete nano-foamed composition to the foam is 1:(12-40).

[0086] According to some embodiments of the method for preparing foamed concrete of the present invention, in the step of foaming the foamed concrete nano-foamed composition through a foaming machine, the volume ratio of the foamed concrete nano-foamed composition to the foam is 1:(12-30). In some specific embodiments, the volume ratio of the foamed concrete nano-foamed composition to the foam can be selected from 1:15, 1:20 or 1:25.

[0087] The fifth aspect of the present invention provides the use of the foamed concrete described in the third aspect of the present invention in building materials, house construction, road and bridge engineering, cast-in-place backfill engineering, mine goaf backfill or garbage landfill.

[0088] According to some embodiments of the foamed concrete application of the present invention, the building material includes ceramsite foamed concrete interior wall panels, assembled exterior wall panels or furniture core materials.

[0089] According to some embodiments of the foam concrete application of the present invention, the house construction includes building foundation pit fertilizer trough backfill, basement roof, sidewalk, parking lot backfill, roof insulation or self-leveling floor.

[0090] According to some embodiments of the foam concrete application of the present invention, the road and bridge engineering includes backfilling of soft foundation roadbed, lane widening, backfilling of tunnel top plate, backfilling of bridge abutment, backfilling of underground pipelines or backfilling of road cavities.

[0091] The beneficial effects of the present invention are:

[0092] The foam concrete nano foaming agent provided by the present invention has the advantages of low cost and good foaming effect. The nano foam produced by the foaming agent has high stability and is applied to the preparation of foam concrete materials. The dry density range of the foam concrete is wide (reaching 180kg / m 3 ~1500kg / m 3 ), low collapse rate (as low as one thousandth), and has good mechanical properties, flow properties, shrinkage properties, stability properties and thermal insulation properties. It has broad application prospects and is suitable for many fields such as building materials, house construction, road and bridge engineering, cast-in-place backfill engineering, mine goaf backfill and garbage landfill.

[0093] Specifically, compared with the prior art, the present invention has the following advantages:

[0094] 1. The present invention establishes a foaming system composed of cellulose, water-soluble polymer materials, surfactants and nanoparticles, wherein cellulose can adjust the viscosity of the solution and improve the stability of the foam; the water-soluble polymer materials can enhance the compatibility of the foam with cement slurry, enhance the mechanical properties of the foamed concrete, and help stabilize the foam; the main function of the surfactant is foaming; the nanoparticles, as foam stabilizers, can synergize with other components of the foaming agent to produce nano foams with small pores and good stability. By using this foam concrete nano foaming agent for physical foaming, the volume of the produced nano foam is 3600 to 12000 times the volume of the foaming agent, and the foaming efficiency is very high.

[0095] 2. The raw materials of the foaming agent of the present invention are easily available and low in cost, especially the amount of nanoparticles used is relatively small, thus reducing production costs and being highly competitive in the market.

[0096] 3. By mixing the foaming agent of the present invention with water for foaming, the dilution multiple of the foaming agent is large, which can reach 200 to 500, and the foaming multiple is high, which is 15 to 40 times. The generated foam volume is large and the foaming efficiency is good.

[0097] 4. The organic functional groups in the foaming agent of the present invention have a suitable ratio. These organic chain segments can form a strong network structure on the bubble surface in the water environment through hydrogen bonds or even chemical bonds, so that the stability of the foam is higher.

[0098] 5. The nano foaming agent of the present invention is used to prepare foamed concrete materials, and foamed concrete with a wider range of dry density can be obtained, and the dry density reaches 180kg / m 3 ~1500kg / m 3 , specifically a lower ultimate density. This type of foam concrete has the advantages of high compressive strength, low water absorption, high fluidity, small shrinkage, low collapse rate (only one thousandth), and good thermal insulation performance.

[0099] 6. The foamed concrete preparation method of the present invention is simple, can improve the production efficiency of foamed concrete, has low production cost, is conducive to large-scale industrialization, has a wide range of applications, and has broad market prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0100] Figure 1 It is the collapse performance test result of foam concrete paste. DETAILED DESCRIPTION

[0101] The present invention is further described in detail below by specific examples. Unless otherwise specified, the raw materials, reagents or devices used in the examples and comparative examples can be obtained from conventional commercial sources or can be obtained by prior art methods. Unless otherwise specified, the experiments or test methods are conventional methods in the art.

[0102] The test methods for compressive strength, water absorption, paste fluidity, freeze-thaw cycle and drying shrinkage of foamed concrete are described as follows:

[0103] The compressive strength and water absorption of foam concrete are tested with reference to the standard JG-T266-2011 "Foam Concrete".

[0104] The paste fluidity of foam concrete is tested with reference to the standard JGJ / T 341-2014 "Technical Code for Application of Foam Concrete".

[0105] The freeze-thaw cycle of foam concrete was tested according to the standard JGJ / T 341-2014. Six specimens were prepared and cured for 28 days. Three of them were kept in a standard curing room, and the remaining three were subjected to 40 freeze-thaw cycles to measure the mass loss rate and compressive strength loss rate.

[0106] The drying shrinkage test method of foam concrete is as follows: use a 40mm×40mm×160mm mold with copper heads at both ends to form foam concrete. After 48 hours, remove the mold and place it in a constant temperature and humidity environment (relative humidity 50%, 25°C). The length change of the copper heads at both ends is measured at regular intervals, which is the drying shrinkage value.

[0107] Foaming agent example 1

[0108] The foam concrete nano foaming agent of this example is composed of 40wt% hydroxypropyl methylcellulose, 40wt% polyvinyl alcohol, 12wt% sodium lauryl sulfate and 8wt% nano alumina.

[0109] The preparation method of the foamed concrete nano foaming agent of this example is to uniformly mix hydroxypropyl methylcellulose, polyvinyl alcohol, sodium lauryl sulfate and nano alumina according to a proportion, so as to obtain the foamed concrete nano foaming agent of this example.

[0110] Foaming agent example 2

[0111] The foam concrete nano foaming agent of this example is composed of 40wt% hydroxyethyl cellulose, 40wt% polyvinyl alcohol, 5wt% sodium lauryl sulfate and 15wt% nano alumina.

[0112] The preparation method of the foamed concrete nano foaming agent of this example is to uniformly mix hydroxyethyl cellulose, polyvinyl alcohol, sodium dodecyl sulfate and nano alumina according to a proportion, so as to obtain the foamed concrete nano foaming agent of this example.

[0113] Foaming agent example 3

[0114] The foam concrete nano foaming agent of this example is composed of 30wt% hydroxyethyl cellulose, 35wt% polyvinyl alcohol, 10wt% sodium lauryl sulfate and 25wt% nano alumina.

[0115] The preparation method of the foamed concrete nano foaming agent of this example is to uniformly mix hydroxyethyl cellulose, polyvinyl alcohol, sodium dodecyl sulfate and nano alumina according to a proportion, so as to obtain the foamed concrete nano foaming agent of this example.

[0116] Foaming agent example 4

[0117] The foam concrete nano foaming agent of this example is composed of 40wt% hydroxypropyl methylcellulose, 30wt% polyvinyl alcohol, 20wt% sodium lauryl sulfate and 10wt% nano alumina.

[0118] The preparation method of the foamed concrete nano foaming agent of this example is to uniformly mix hydroxypropyl methylcellulose, polyvinyl alcohol, sodium lauryl sulfate and nano alumina according to a proportion, so as to obtain the foamed concrete nano foaming agent of this example.

[0119] Foaming agent example 5

[0120] The foam concrete nano foaming agent of this example is composed of 20wt% hydroxypropyl methylcellulose, 40wt% polyvinyl alcohol, 20wt% sodium lauryl sulfate and 20wt% nano alumina.

[0121] The preparation method of the foamed concrete nano foaming agent of this example is to uniformly mix hydroxypropyl methylcellulose, polyvinyl alcohol, sodium lauryl sulfate and nano alumina according to a proportion, so as to obtain the foamed concrete nano foaming agent of this example.

[0122] Foaming agent comparative example 1

[0123] The foam concrete nano foaming agent of this example is composed of 5wt% polyacrylamide, 33wt% methyl cellulose, 15wt% polyvinyl alcohol, 15wt% polyethylene oxide, 2wt% polyacrylic acid, 20wt% sodium lauryl sulfate and 10wt% nano alumina.

[0124] The preparation method of the foamed concrete nano foaming agent of this example is to uniformly mix polyacrylamide, methyl cellulose, polyvinyl alcohol, polyethylene oxide, polyacrylic acid, sodium dodecyl sulfate and nano alumina according to a proportion, so as to obtain the foamed concrete nano foaming agent of this example.

[0125] Foaming agent solution examples 1 to 5

[0126] The foamed concrete nano foaming agents of Examples 1 to 5 were respectively mixed with water at a mass ratio of 1:300 to obtain the foaming agent solutions of Examples 1 to 5.

[0127] The foaming agent solution Example 1 was injected into a special foaming machine equipped with a frequency converter, and the air pressure and water pressure were adjusted to produce nano foam. The ratio of the produced foam volume to the foaming agent solution volume was 20:1, that is, the volume ratio of the foam to the foaming agent was 6000:1.

[0128] The foaming agent solutions of Examples 2 to 5 were foamed in the same manner, and the foaming effect obtained was equivalent to that of the foaming agent solution of Example 1. The experimental results show that when the foaming agent solution of the embodiment of the present invention is used for foaming, the ratio of the volume of the foam produced to the volume of the foaming agent solution is (15-40):1, that is, the volume ratio of the foam to the foaming agent is (4500-12000):1.

[0129] The example 1 of the foamed concrete nano foaming agent was sent for testing. According to JC / T 2199-2013 "Foaming agent for foamed concrete", the dilution test was carried out at a dilution ratio of foaming agent: water = 1:303. The test results are as follows: the foam density is 40g / mL, the foaming multiple is 25, the 1h settlement distance is 33mm, and the 1h water bleeding rate is 21%. According to the standard, the foaming multiple of the first-class foam is 15-30, the 1h settlement distance is ≤50mm, and the 1h water bleeding rate is ≤70%. It can be seen that the foamed concrete nano foaming agent of the embodiment of the present invention can meet the technical index requirements of the first-class product in JC / T 2199-2013.

[0130] By adopting the same method as above, the foam concrete nano foaming agent of comparative example 1 is mixed with water in the same mass ratio as the foaming agent solution embodiment 1 to obtain the foaming agent solution of comparative example 1, and a performance test is performed. The test results show that the foaming multiple of the foam concrete nano foaming agent of comparative example 1 is 12, which is significantly lower than the foaming multiple of the foam concrete nano foaming agent of embodiment 1. Moreover, comparative example 1 uses more preparation raw materials, which is not conducive to reducing production costs. Therefore, the foam concrete nano foaming agent provided by the present invention has a large foaming multiple, the output foam has good stability, and the cost is low, which is more conducive to improving the production efficiency of foam concrete, improving the performance of foam concrete, and has good economic and social benefits.

[0131] In order to calculate the density of the foam, the nano foam produced by the above-mentioned foaming agent solution Example 1 was added to a 1L measuring cup for weighing. In comparison, commercially available animal protein foaming agent (produced by Hangzhou Zhonghua Company, foaming agent comparative example 2) and plant protein foaming agent (produced by Qingdao Yousuo Company, foaming agent comparative example 3) were used to perform the same density test. Foaming agent comparative examples 2 and 3 were both diluted with water according to the dilution multiple provided by the manufacturer for foaming, and the dilution multiples of both were 20. The experimental results show that under the same foaming conditions, the density of the nano foam produced by foaming agent example 1 is 118kg / m 3 , while the foam density produced by the foaming agent comparative example 2 is 53kg / m 3 The foam density produced by the foaming agent comparative example 3 is 48kg / m 3 It can be seen that the density of the nano foam produced in this embodiment is much higher than that of the animal protein foaming agent and the plant protein foaming agent. This is because the cohesive force between the foaming agent molecules in the embodiment is greater, so under the same foaming conditions, the density is greater and the foam is more stable.

[0132] By using the foam concrete nano foaming agent provided in the embodiment of the present invention, nano foam is produced by physical foaming, and then used to prepare foam concrete, the dry density range of the foam concrete can be 180kg / m 3 ~1500kg / m 3 , with a wider range of applications. The minimum dry density of foam concrete can reach 180kg / m 3 Its 28-day compressive strength is ≥0.2MPa; the maximum dry density of foam concrete can reach 1500kg / m 3 , its 28-day compressive strength is ≥40MPa. However, the minimum dry density of foamed concrete that can be achieved by existing foaming agents is only about 300kg / m 3 , it is impossible to produce products with lower density.

[0133] The foamed concrete provided by the present invention has good water resistance. When the dry density is 450kg / m 3When the water absorption rate of the foamed concrete is tested for 2 hours, it can be as low as 7%. Under the same preparation and testing conditions, the water absorption rate of the foamed concrete prepared by foaming with the commercially available Grace foaming agent is about 40%. It can be seen that the water absorption rate of the foamed concrete provided by the present invention is significantly lower than that of the existing foamed concrete products.

[0134] The following is a further detailed description in conjunction with a specific foam concrete embodiment.

[0135] Foamed concrete examples 1 to 4

[0136] The foam concrete test was conducted using ordinary Portland cement with a strength of 42.5 and the nano foam produced by the foaming agent solution Example 1. The test results of the foam concrete Examples 1 to 4 are shown in Table 1.

[0137] Table 1 Test results of Examples 1 to 4

[0138]

[0139] The preparation method of foamed concrete Example 1 is: according to the proportion composition in Table 1, cement and water are mixed to obtain cement slurry, and then the cement slurry is evenly mixed with the nano foam produced by foaming agent solution Example 1 to obtain the foamed concrete of this example.

[0140] For foamed concrete examples 2 to 4, the respective foamed concretes were prepared according to the formulations of foamed concrete examples 2 to 4 in Table 1 and with reference to the preparation method of foamed concrete example 1.

[0141] The performance tests of foam concrete examples 1 to 4 were conducted, and it was found that the compressive strength of foam concrete example 3 reached 0.9 MPa to 1 MPa after 3 days. The test results of the 7-day, 14-day, and 28-day compressive strength, 28-day saturated water absorption compressive strength and drying compressive strength, slurry fluidity, and 14-day and 90-day drying shrinkage values ​​of foam concrete examples 1 to 4 are shown in Table 2. The compressive strength test results in Table 2 are the average values ​​of 3 test pieces.

[0142] Table 2 Performance test results of foam concrete examples 1 to 4

[0143] Test items Example 1 Example 2 Example 3 Example 4 7-day compressive strength (MPa) 4.76 3.23 0.58 0.49 14-day compressive strength (MPa) 5.26 3.60 0.85 0.61 28-day compressive strength (MPa) 7.20 4.60 1.25 0.73 28-day saturated water absorption compressive strength (MPa) 6.06 4.13 1.12 0.64 28-day saturated water absorption drying compressive strength (MPa) 7.26 4.73 1.26 0.76 Slurry fluidity (mm) 239 248 209 202 14-day drying shrinkage value (mm / m) 2.44 2.81 4.24 4.67 90 days drying shrinkage value (mm / m) 4.08 4.39 5.82 6.28

[0144] According to the experimental results in Table 2, it can be seen that:

[0145] 1. Compressive strength: The compressive strength of foamed concrete is good, and the compressive strength at 7 days, 14 days and 28 days shows an increasing trend. The greater the density of foamed concrete, the higher the increase in compressive strength.

[0146] 2. Paste fluidity: Since the bubbles in the foam play a certain dispersing and lubricating role on the cement base material, the foam concrete has good fluidity.

[0147] 3. Drying shrinkage: As the density of foamed concrete increases, its drying shrinkage shows a trend of gradually decreasing. This is because the greater the density of foamed concrete, the less foam is added, and therefore the less water is introduced. Therefore, the water-cement ratio of the foamed concrete paste decreases, resulting in a decrease in drying shrinkage. When the density is higher, there are fewer interconnected pores and large pores inside, and fewer defects. The specimen is subjected to greater internal stress during the drying shrinkage process, resulting in a decrease in drying shrinkage.

[0148] Foamed concrete examples 5-6 and comparative examples 1-2

[0149] The foam produced by the foaming agent and the P·II silicate cement with a strength of 52.5 grade were used to prepare the foamed concrete.

[0150] The nano foams of foamed concrete examples 5 to 6 are prepared by foaming the foaming agent example 1, and the mass ratio of the foaming agent to water is 1:300. Please refer to the aforementioned foaming agent solution example 1 and its foaming method.

[0151] Foam concrete Example 5 is composed of 500 kg cement, 250 kg water and 0.9 m 3 The final foam concrete has a wet density of about 600kg / m 3 .

[0152] Foam concrete Example 6 is composed of 500 kg cement, 250 kg water and 1 m 3 The final foam concrete has a wet density of about 700kg / m 3 .

[0153] The foaming agent comparative example 2 (animal protein foaming agent) and the foaming agent comparative example 3 (plant protein foaming agent) were respectively used for foaming, and the foamed concrete comparative example 1 (foaming with the foaming agent comparative example 2) and the foamed concrete comparative example 2 (foaming with the foaming agent comparative example 3) were prepared according to the composition of the foamed concrete example 5. Among them, the dilution multiples of the foaming agents comparative examples 1 and 2 were all 20.

[0154] After testing, the drying shrinkage value of foam concrete example 5 after 90 days is 2.5 mm / m, the drying shrinkage value of foam concrete comparative example 1 after 90 days is 2.7 mm / m, and the drying shrinkage value of foam concrete comparative example 2 after 90 days is 3.0 mm / m. It can be seen that foam concrete example 5 has better drying shrinkage performance, which may be related to its pore structure. Lower pore connectivity helps to reduce the drying shrinkage of foam concrete.

[0155] The foamed concrete example 5, the foamed concrete comparative example 1, and the foamed concrete comparative example 2 were subjected to freeze-thaw cycle tests. The experimental results showed that the foamed concrete example 5 was subjected to 40 freeze-thaw cycle tests. Compared with the specimens before the freeze-thaw test, the mass loss rate was 2.5%, and the compressive strength loss rate was 15.2%. The foamed concrete comparative example 1 made by foaming with an animal protein foaming agent had a mass loss rate of 4.3% and a compressive strength loss rate of 20.6% after 40 freeze-thaw cycle tests. The foamed concrete comparative example 2 made by foaming with a plant protein foaming agent had a mass loss rate of 5.9% and a compressive strength loss rate of 27.3% after 40 freeze-thaw cycle tests. It can be seen that the foamed concrete of this embodiment has better freeze-thaw cycle performance and is more stable.

[0156] The slurry of the foamed concrete example 6 was tested for collapse performance. The specific test method was: pour the foamed concrete slurry into a cylindrical tube with a length of 200 cm and a diameter of 3 cm, and test the collapse degree at different times (initial, 1 hour and 24 hours). At the same time, the commercially available Grace foaming agent was also used to make foamed concrete slurry for the same experimental comparison. The dilution factor of the Grace foaming agent was also 20. Figure 1 It is the collapse performance test result of foam concrete paste. Figure 1 It can be seen that the nano foam concrete slurry prepared by using the foam concrete nano foaming agent has super high stability, and its collapse degree is less than 0.1% after being placed for 24 hours, and there is no surface deformation or cracking. The foam concrete slurry prepared by using the Grace foaming agent has a collapse degree of 1% after being placed for 24 hours, and the surface shrinkage and cracking are serious. Therefore, the nano foam concrete product made by the foam concrete nano foaming agent of the present invention has a collapse rate of only one thousandth, showing excellent stability.

[0157] In addition, after testing, the thermal conductivity of the blocks made of the foamed concrete of Examples 1 to 6 is 0.1 to 0.15 W / (m·K), which proves that it has good thermal insulation performance. The blocks made of the foamed concrete of Examples 1 to 6 have uniform pore distribution, extremely small pore size, and an average size of about 60 μm, while the average pore size of the existing foamed concrete blocks including Comparative Examples 1 to 2 ranges from 400 μm to 500 μm. Therefore, the nano foam produced by the foaming agent of the present invention is used to prepare foamed concrete, which contains smaller closed pores, and is therefore beneficial to improving the mechanical strength, shrinkage performance and stability of the foamed concrete.

[0158] Foamed concrete example 7

[0159] The foam concrete test was carried out using ordinary Portland cement with a strength of 42.5 and the nano foam produced by the foaming agent solution Example 1.

[0160] The raw material composition of the foam concrete in this example is as follows: 360kg cement, 190kg water, 0.5kg rubber powder, 0.7kg hydroxypropyl methylcellulose, 0.3kg PP fiber, 200kg ceramsite, 100kg sand, 180kg slag, 6kg water reducer, and 1000L nano foam.

[0161] The preparation method of foamed concrete in this example is:

[0162] According to the proportion, cement, water, rubber powder, cellulose, PP fiber, ceramsite, sand, slag and water reducing agent are mixed evenly to obtain cement slurry;

[0163] The cement slurry and the nano foam produced in the foaming agent solution embodiment 1 are mixed evenly to obtain the foamed concrete of this embodiment.

[0164] The theoretical density of foam concrete in this example is 1037kg / m 3 , the actual dry density is 1130kg / m 3 After testing, the compressive strength of the foamed concrete in this example reached 3.2MPa after 3 days.

[0165] Foamed concrete example 8

[0166] The types of raw materials used in this example are the same as those in foam concrete example 7.

[0167] The raw material composition of the foam concrete in this example is as follows: 360kg cement, 190kg water, 0.5kg rubber powder, 0.7kg hydroxypropyl methylcellulose, 0.3kg PP fiber, 200kg ceramsite, 100kg sand, 180kg slag, 6kg water reducer, and 600L nano foam.

[0168] The preparation method of the foamed concrete in this example is the same as that of the foamed concrete example 7, and the difference between the two is only the amount of nano foam used.

[0169] The theoretical density of foam concrete in this example is 1037kg / m 3 , the actual dry density is 1200kg / m 3 After testing, the compressive strength of the foamed concrete in this example reached 4.3MPa after 3 days.

[0170] It can be seen from the above experimental results that the foamed concrete provided by the present invention has better mechanical properties, flow properties, shrinkage properties, stability properties and thermal insulation properties, and has high compressive strength, low water absorption, high fluidity, small shrinkage and low collapse rate. Therefore, the foamed concrete product prepared by foaming with the foaming agent of the present invention can be applied to building construction, such as cast-in-place engineering construction, and can also be used as a wall insulation material, and has broad application prospects in garbage landfill, pit filling, roof insulation or self-leveling floor, etc.

[0171] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A foam concrete nano foaming agent, characterized in that: It is composed of the following components in percentage by mass: The cellulose is at least one of hydroxyethyl cellulose, hydroxypropyl methyl cellulose, cellulose acetate butyrate, and microcrystalline cellulose; The water-soluble polymer material is at least one of polyacrylamide, sodium polyacrylate, polyvinyl alcohol, polyethyleneimine and polyvinyl pyrrolidone.

2. A foam concrete nano foaming agent according to claim 1, characterized in that, The components of the foam concrete nano foaming agent are: The surfactant is at least one of a sulfate surfactant, a sulfonate surfactant, and a fatty alcohol polyoxyethylene ether; And / or, the nanoparticles are at least one of nano-silicon dioxide, nano-titanium dioxide, nano-aluminum oxide, and nano-calcium carbonate.

3. A foamed concrete nano foaming agent according to claim 1 or 2, characterized in that, The foam concrete nano foaming agent is composed of the following components in percentage by mass: 20% to 40% of hydroxypropyl methylcellulose, 20% to 40% of polyvinyl alcohol, 5% to 20% of sodium lauryl sulfate, and 5% to 25% of nano aluminum oxide.

4. A foamed concrete nano foaming agent according to claim 3, characterized in that: The volume ratio of the foam concrete nano foaming agent to the nano foam produced by the foaming agent is 1:(3600-12000).

5. A foamed concrete nano-foaming composition, characterized in that: The invention comprises the foam concrete nano foaming agent according to any one of claims 1 to 4 and water; the mass ratio of the foam concrete nano foaming agent to water is 1:(200-500).

6. A foamed concrete nano-foaming composition according to claim 5, characterized in that: The foaming multiple of the foam concrete nano foaming composition is 15-40.

7. A foamed concrete, characterized in that: The invention comprises the following components: a cement-based mixture and nano foam; The cement-based mixture includes cement and water; The nano foam is prepared by foaming the foamed concrete nano foam composition according to claim 5 or 6; The mass ratio of the cement to the water is 1:(0.3-0.6); The ratio of the cement to the nano foam is 1kg:(0.5-4)L.

8. The foamed concrete according to claim 7, characterized in that: The cement-based mixture further comprises at least one of the following components: rubber powder, cellulose, polypropylene fiber, ceramsite, sand, slag, fly ash, glass microspheres, and a water reducing agent.

9. A method for preparing foamed concrete as claimed in claim 7 or 8, characterized in that: The steps include: The foamed concrete nano-foam composition is foamed by a foaming machine to obtain nano-foam; mixing the components of the cement-based mixture to obtain a cement-based mixture; The cement-based mixture is mixed with the nano foam to obtain the foamed concrete.

10. Use of the foamed concrete according to claim 7 or 8 in building materials, house construction, road and bridge engineering, cast-in-place backfill engineering, mine goaf backfill or garbage landfill.

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