CN117430385A

CN117430385A - Foam concrete and preparation method thereof

Info

Publication number: CN117430385A
Application number: CN202311363251.1A
Authority: CN
Inventors: 陈发明; 陈利祥; 周浩; 吕龙飞; 何静
Original assignee: Shandong Datong Construction Group Co ltd
Current assignee: Shandong Datong Construction Group Co ltd
Priority date: 2023-10-20
Filing date: 2023-10-20
Publication date: 2024-01-23
Anticipated expiration: 2043-10-20
Also published as: CN117430385B

Abstract

The application relates to the field of foam concrete, and in particular discloses foam concrete and a preparation method thereof, wherein the foam concrete comprises the following raw materials in parts by weight: 50 parts of silicate cement; 78-86 parts of fine aggregate; 27-29 parts of mixing water; 5.4-6.5 parts of foaming agent; 0.2-0.6 part of water reducer; 0.4-0.8 part of flow promoter; the foaming agent comprises the following raw materials in parts by weight: 10 parts of lauroyl disodium glutamate; 2-5 parts of anionic surfactant; 2.2-2.4 parts of foam stabilizer; 1-3 parts of 1, 2-propylene glycol; 1-2.5 parts of superfine modified carbon powder. The preparation method comprises the following steps: stirring silicate cement and fine aggregate; adding mixing water, a water reducing agent and a flow promoter, and stirring to obtain a mixture; preparing foam by using a foaming agent; preparing foam concrete slurry by using the foam and the mixture; and pouring and curing to obtain the foam concrete. The foam stability is improved, and the probability of pressure cracking of the foam concrete is reduced.

Description

Foam concrete and preparation method thereof

Technical Field

The application relates to the field of foam concrete, in particular to foam concrete and a preparation method thereof.

Background

The foam concrete is concrete which is formed by introducing gases such as nitrogen, carbon dioxide, oxygen and the like into cement paste or cement mortar through a chemical method or a physical method foaming process and curing and contains a large number of closed pores and has certain strength. Because of the existence of a large number of closed air holes, the foam concrete has light weight, warmth retention, heat insulation, sound insulation and fire resistance, and is widely applied to the fields of backfilling engineering, heat-insulating building, playground, earthquake-resistant structure and the like.

In the two production processes of the foam concrete, the physical foaming process is widely applied. The physical method foaming mainly comprises two modes of introducing bubbles, namely directly adding a foaming agent into cement paste or cement mortar, and directly wrapping gas in the cement paste or cement mortar by mechanical high-speed stirring to form foam concrete; and secondly, preparing the foaming agent into foam by using a stirrer or an air compressor, and introducing the foam into cement paste or cement mortar to form foam concrete. The fluidity of the foam concrete is reduced due to the increase of the foam, and the edge of the mold is leaked when the foam concrete is injected into the mold.

In the related art, after the foam concrete is poured, the foam concrete is fully filled in the mould in a vibration mode and the like, but partial bubbles in the foam concrete are broken due to vibration or adjacent bubbles are communicated with each other, the uniformity of closed air holes in the foam concrete is reduced, when the concrete is pressed, the pressure is easily concentrated to macropores, the walls of the macropores are easily broken, and continuous cracks are generated in the foam concrete in severe cases.

Disclosure of Invention

In order to improve foam stability and reduce the probability of pressure cracking of foam concrete, the application provides foam concrete and a preparation method thereof.

In a first aspect, the present application provides a foamed concrete adopting the following technical scheme:

the foam concrete comprises the following raw materials in parts by weight: 50 parts of silicate cement; 78-86 parts of fine aggregate; 27-29 parts of mixing water; 5.4-6.5 parts of foaming agent; 0.2-0.6 part of water reducer; 0.4-0.6 part of flow promoter; the foaming agent comprises the following raw materials in parts by weight: 10 parts of lauroyl disodium glutamate; 2-5 parts of anionic surfactant; 2.2-2.4 parts of foam stabilizer; 1-3 parts of 1, 2-propylene glycol; 1-2.5 parts of superfine modified carbon powder.

By adopting the technical scheme, the lauroyl disodium glutamate and the anionic surfactant are cooperatively adsorbed at the gas-liquid interface to form the membrane structure, the hydrophobic groups of the lauroyl disodium glutamate play a role in shielding the negative charges densely arranged by the directional arrangement of the anionic surfactant, so that the repulsive force is reduced, the stability and the toughness of the membrane structure are improved, the stability of foam is improved, when the foam concrete is fully filled in a mould in an oscillating mode and the like, the foam is not easy to crack or communicate, the closed air holes in the foam concrete are uniformly distributed and uniform in size, and the probability of pressure cracking of the foam concrete is reduced. The 1, 2-propylene glycol, the disodium lauroyl glutamate and the anionic surfactant are matched for use, and the 1, 2-propylene glycol is used as a regulator, so that a membrane structure formed by the disodium lauroyl glutamate and the anionic surfactant is nested to form a double-layer membrane, the competitive adsorption of the disodium lauroyl glutamate and the anionic surfactant is reduced, the stability of foam is improved, and the probability of pressure cracking of foam concrete is further reduced.

The foam stabilizer increases the surface viscosity of the foam, increases the solution viscosity, prevents the foam from draining, and reduces the bleeding rate of the foaming agent.

Optionally, the anionic surfactant is selected from sodium dodecyl benzene sulfonate.

By adopting the technical scheme, when the foam formed by the foaming agent is used for preparing the foam concrete, the foam formed by the sodium dodecyl benzene sulfonate forms a layer of adsorption film residues on the surfaces of other materials of the foam concrete, so that the uniformity of the dispersion of the other materials is improved, the overall strength of the foam concrete is improved, and the probability of pressure cracking of the foam concrete is reduced.

Optionally, the foam stabilizer comprises polyacrylamide and hydroxypropyl methylcellulose, wherein the weight ratio of the polyacrylamide to the hydroxypropyl methylcellulose is (5:19) - (8:3).

Through adopting above-mentioned technical scheme, polyacrylamide and hydroxypropyl methylcellulose cooperation have improved the elasticity and the rigidity of foam, have improved foam stability, and when mode such as adopting vibration made foam concrete fully fill the mould, the foam is difficult for breaking or intercommunication, and airtight gas pocket distribution and size in the foam concrete are even, reduce the probability that foam concrete pressurized fracture.

Optionally, the preparation of the superfine modified carbon powder comprises the following steps: mixing the powdered wool carbon, hexadecyl trimethyl ammonium chloride and butyl ether, heating in a constant-temperature water bath, intermittently stirring, treating for 30-40min, taking out the powdered wool carbon, drying at normal temperature, and grinding to obtain superfine modified carbon powder.

By adopting the technical scheme, the carbon powder formed by wool is of a porous structure, the intermolecular attraction of the surface of the wool carbon powder is weakened by the adsorption and filling of butyl ether, the superfine modified carbon powder plays an in-situ hydrophobic effect in a foam system formed by a foaming agent, the surface of the superfine modified carbon powder is positively charged by the adsorption and filling of cetyl trimethyl ammonium chloride, and the disodium lauroyl glutamate and sodium dodecyl benzene sulfonate molecules are adsorbed on the surface of the superfine modified carbon powder by electrostatic attraction to form a monomolecular layer, so that the surface of the superfine modified carbon powder is hydrophobic, the superfine modified carbon powder is promoted to be adsorbed on a gas/liquid interface to form a layer of hard supporting structure, stable solid, liquid and gas three-phase foam is formed, the stability of the foam is improved, and the probability of pressure cracking of foam concrete is reduced.

Optionally, the preparation of the wool carbon powder comprises the following steps of cutting waste wool products into short fibers, rinsing, airing, treating for 20-30min at 800-850 ℃, taking out, cooling to 100-120 ℃, and grinding into powder to obtain the wool carbon powder.

By adopting the technical scheme, the waste wool products are recycled, and the resource utilization rate is improved.

Optionally, the preparation of the foaming agent comprises the following steps: preparing a foam stabilizer and superfine modified carbon powder; uniformly mixing lauroyl disodium glutamate and anionic surfactant, and magnetically stirring at 35-45deg.C for 10-20min to obtain mixed solution; adding the foam stabilizer, the 1, 2-propylene glycol and the superfine modified carbon powder into the mixed solution, and continuously stirring for 1-2h to obtain the foaming agent.

By adopting the technical scheme, the lauroyl disodium glutamate and the anionic surfactant are uniformly mixed firstly, then the 1, 2-propanediol and the superfine modified carbon powder are added, and the components are uniformly mixed by stirring.

Optionally, the flow promoter is selected from pine branch tobacco tar, and the preparation steps comprise: collecting tobacco tar burnt by pine branch.

By adopting the technical scheme, the collected pine branch tobacco tar contains the sublimated rosin and the potassium carbonate micro powder, and the rosin plays a lubricating role after heating, so that the fluidity of the foam concrete is improved. When the foam concrete is prepared, the potassium carbonate micro powder and free calcium ions in the mixing water generate calcium hydroxide, so that the calcium hydroxide has a catalytic effect on the coagulation of silicate, the strength of the foam concrete is enhanced, and the probability of pressure cracking of the foam concrete is reduced.

In a second aspect, the preparation method of the foam concrete provided by the application adopts the following technical scheme:

the preparation method of the foam concrete comprises the following steps:

s1, mixing silicate cement and fine aggregate to obtain a dry mixed material;

s2, uniformly mixing the mixing water and the water reducer to obtain a mixed solution, pouring the mixed solution into a dry mixed material, then adding heated pine branch tobacco tar, and uniformly stirring to obtain a mixed material;

s3, uniformly mixing the foaming agent and foaming water to obtain foaming liquid; introducing compressed air into the foaming liquid by using an air compressor to form foam;

s4, adding foam into the mixture, and stirring for 2-5min at 20-30r/min to obtain foam concrete slurry;

s5, injecting the foam concrete slurry into a mold, filling up after oscillation, and curing to obtain the foam concrete.

By adopting the technical scheme, after the foam is added, the fluidity of the foam concrete is reduced, when the foam concrete is injected into a mold, the phenomenon of filling leakage exists at the corners of the mold, and the pine branch tobacco tar is used as a flow promoter, so that the fluidity of the foam concrete is improved, and the probability of corner falling due to the lack of edges of the foam concrete is reduced. During the curing of the foam concrete, the pine branch tobacco tar is solidified and has certain strength, so that the compressive capacity of the foam concrete is improved, and the probability of compressive cracking of the foam concrete is reduced.

Optionally, the volume ratio of the foaming agent to the foaming water is 1 (30-45).

Through adopting above-mentioned technical scheme, based on the foaming agent of this application preparation, after foaming agent and foaming water adopt above-mentioned volume ratio to mix, the foam of preparation is little and intensive, and foam stability is good.

In summary, the present application includes at least one of the following beneficial technical effects:

1. the sodium lauroyl glutamate and the sodium dodecyl benzene sulfonate are cooperatively adsorbed at a gas-liquid interface to form a membrane structure, hydrophobic groups of the sodium lauroyl glutamate play a role in shielding dense negative charges caused by directional arrangement of the sodium dodecyl benzene sulfonate, repulsive force is reduced, stability and toughness of the membrane structure are improved, and accordingly stability of foam is improved, 1, 2-propanediol is added at the moment to serve as a regulator, the membrane structure formed by the sodium lauroyl glutamate and the sodium dodecyl benzene sulfonate is nested to form a double-layer membrane, competitive adsorption of the sodium lauroyl glutamate and an anionic surfactant is reduced, stability of foam is improved, when the foam concrete is fully filled into a mould in an oscillating mode, the foam is not easy to crack or communicate, closed air holes in the foam concrete are uniformly distributed, and the size of the closed air holes is uniform, so that probability of pressure cracking of the foam concrete is reduced.

2. Short fibers after the waste wool products are sheared are processed to form porous wool carbon powder, wool carbon butyl ether and hexadecyl trimethyl ammonium chloride are matched to form superfine modified carbon powder with positive charges on the surface and weakened intermolecular attraction on the surface, lauroyl disodium glutamate and sodium dodecyl benzene sulfonate molecules are adsorbed on the surface of the superfine modified carbon powder through electrostatic attraction to form a monomolecular layer, the surface of the superfine modified carbon powder is hydrophobic, the superfine modified carbon powder is promoted to be adsorbed on a gas/liquid interface to form a layer of hard supporting structure, stable solid, liquid and gas three-phase foam is formed, the stability of the foam is improved, and the probability of pressure cracking of foam concrete is reduced.

3. The waste wool products are recycled, so that the resource utilization rate is improved.

Detailed Description

The present application is described in further detail below in connection with examples and comparative examples.

The following examples, in which the specific conditions are not specified, are conducted under conventional conditions or conditions recommended by the manufacturer, and the raw materials used in the following examples are commercially available from ordinary sources except for the specific descriptions.

The sodium dodecyl benzene sulfonate is linear. The Portland cement adopts P.O42.5 Portland cement, the screen residue of a 45 mu m screen is 3.5%, the initial setting time is 180min, the final setting time is 232min, the 28d compressive strength is 46.2MPa, and the 28d flexural strength is 7.2MPa. The fine aggregate is selected from basalt, and the maximum grain diameter is not more than 0.45mm. The foam stabilizer is selected from alkyl alcohol amide, and the water reducer is selected from naphthalene water reducer. The common commercial carbon powder is charcoal powder with specific gravity of 0.55 and particle size of 325 mesh. The common commercial foaming agent is cement foaming agent, liquid anionic surfactant, dilution factor of 30 times, solid content of 28% +/-0.5%, foaming factor of 20 times, bubble diameter of 1-2mm, sedimentation distance of 1h of 7 mm+/-0.2 mm and bleeding rate of 80%. The foaming water is water meeting the related technical requirements in JGJ 63-2006 water for concrete.

Preparation example

Preparation example 1

S1, uniformly mixing 0.5kg of polyacrylamide and 1.9kg of hydroxypropyl methylcellulose, and taking the mixture as a foam stabilizer;

s2, cutting waste wool products into short fibers with the length of less than 5mm, rinsing with clear water, airing, then placing into a high-temperature oven for treatment at 800 ℃ for 30min, taking out, cooling to 100 ℃, and grinding into powder to obtain the carbon powder; mixing 4kg of wool carbon powder, 0.5kg of hexadecyl trimethyl ammonium chloride and 1kg of butyl ether, heating in a constant-temperature water bath at 100 ℃, intermittently stirring for 30min, stirring for 5min, stopping for 5min, taking out the wool carbon powder, treating for 2min by a dehydration procedure of a washing machine for experiments, drying at normal temperature until the moisture regain is stable, and grinding and screening to obtain 625-mesh superfine modified carbon powder;

s3, uniformly mixing 10kg of lauroyl disodium glutamate and 2kg of sodium dodecyl benzene sulfonate, and magnetically stirring for 20min at 35 ℃ to obtain a mixed solution;

s4, adding the foam stabilizer prepared by the S2, 1kg of 1, 2-propylene glycol and 2.5kg of superfine modified carbon powder prepared by the S2 into the mixed solution, and continuously stirring for 1 hour until stirring is uniform, thus obtaining the foaming agent.

Preparation example 2

S1, uniformly mixing 1.1kg of polyacrylamide and 1.2kg of hydroxypropyl methylcellulose, and taking the mixture as a foam stabilizer;

s2, cutting waste wool products into short fibers with the length of less than 5mm, rinsing with clear water, airing, then treating for 25min at 830 ℃, taking out, cooling to 110 ℃, and grinding into powder to obtain the wool carbon powder; mixing 4kg of wool carbon powder, 0.5kg of hexadecyl trimethyl ammonium chloride and 1kg of butyl ether, heating in a constant-temperature water bath at 110 ℃, intermittently stirring for 30min, stirring for 5min, stopping for 5min, taking out the wool carbon powder, treating for 2min by a dehydration procedure of a washing machine for experiments, drying at normal temperature until the moisture regain is stable, and sieving to obtain 625-mesh superfine modified carbon powder;

s3, uniformly mixing 10kg of lauroyl disodium glutamate and 3kg of sodium dodecyl benzene sulfonate, and magnetically stirring at 40 ℃ for 15min to obtain a mixed solution;

s4, adding the foam stabilizer prepared by the S2, 2kg of 1, 2-propylene glycol and 1.8kg of superfine modified carbon powder prepared by the S2 into the mixed solution, and continuously stirring for 1.5 hours until stirring is uniform, thus obtaining the foaming agent.

Preparation example 3

S1, uniformly mixing 1.6kg of polyacrylamide and 0.6kg of hydroxypropyl methylcellulose, and taking the mixture as a foam stabilizer;

s2, cutting waste wool products into short fibers with the length of less than 5mm, rinsing with clear water, airing, treating for 20min at 850 ℃, taking out, cooling to 120 ℃, and grinding into powder to obtain the wool carbon powder; mixing 4kg of wool carbon powder, 0.5kg of hexadecyl trimethyl ammonium chloride and 1kg of butyl ether, heating in a constant-temperature water bath at 120 ℃, intermittently stirring for 30min, stirring for 5min, stopping for 5min, taking out the wool carbon powder, treating for 2min by a dehydration procedure of a washing machine for experiments, drying at normal temperature until the moisture regain is stable, and sieving to obtain 625-mesh superfine modified carbon powder;

s3, uniformly mixing 10kg of lauroyl disodium glutamate and 5kg of sodium dodecyl benzene sulfonate, and magnetically stirring at 45 ℃ for 10min to obtain a mixed solution;

s4, adding the foam stabilizer prepared by the S2, 3kg of 1, 2-propylene glycol and 1kg of superfine modified carbon powder prepared by the S2 into the mixed solution, and continuously stirring for 2 hours until stirring is uniform, thus obtaining the foaming agent.

Preparation example 4

The difference from the preparation example 2 is that: the addition amount of the superfine modified carbon powder in the step S4 is 1kg.

Preparation example 5

The difference from the preparation example 2 is that: the addition amount of the superfine modified carbon powder in the S4 is 2.5kg.

Preparation example 6

The difference from the preparation example 2 is that: 10kg of disodium lauroyl glutamate was replaced with 10kg of sodium dodecylbenzenesulfonate, i.e., no disodium lauroyl glutamate was added and the amount of sodium dodecylbenzenesulfonate added was 13kg.

Preparation example 7

The difference from the preparation example 2 is that: no 1, 2-propanediol was added.

Preparation example 8

The difference from the preparation example 2 is that: no superfine modified carbon powder is added.

Preparation example 9

The difference from the preparation example 2 is that: s2, cutting 4kg of waste wool products into short fibers with the length of less than 5mm, rinsing with clear water, airing, treating for 25min at 830 ℃, taking out, cooling to 110 ℃, grinding into powder, and screening to obtain 625-mesh superfine modified carbon powder.

Preparation example 10

The difference from the preparation example 2 is that: the superfine modified carbon powder is replaced by common commercial carbon powder.

Table 1 raw material table of preparation example

Preparation example Performance test

Test method

1. The expansion ratio of the foaming agent was measured by the method of JC/T2199-2013 foaming agent for foam concrete, wherein the dilution ratio is 40 times, and the test results are shown in Table 2.

2. The foam 1h sedimentation distance (mm) and the 1h bleeding rate (%) of the foaming agent are measured by adopting the method of annex A in JC/T2199-2013 foaming agent for foam concrete, the foam 1h sedimentation rate (%) is calculated by a formula of 7.9.1, and the test results are shown in Table 2 in detail.

Table 2 table of test results for preparation examples

	Expansion ratio of foaming	Foam 1h sedimentation Rate (%)	1h bleeding Rate (%)
				Preparation example 1	39.41	2.87	45.85
Preparation example 2	40.53	2.52	44.32
				Preparation example 3	39.85	2.79	45.13
Preparation example 4	39.04	2.71	45.27
				Preparation example 5	39.33	2.67	45.65
Preparation example 6	32.33	3.75	50.33
				Preparation example 7	31.64	3.70	49.86
Preparation example 8	30.25	3.97	51.64
				Preparation example 9	33.25	3.76	48.92
Preparation example 10	34.33	3.82	49.04

In combination with preparation example 1, preparation example 2 and preparation example 3, a foaming agent with high foaming rate and stable foam was prepared by adjusting the addition amounts of disodium lauroyl glutamate, sodium dodecylbenzenesulfonate, polyacrylamide, hydroxypropyl methylcellulose, 1, 2-propanediol and ultrafine modified carbon powder, and the addition type of ultrafine modified carbon powder.

In combination with preparation example 2, preparation example 4 and preparation example 5, the addition amount of the ultrafine modified carbon powder in preparation example 2 was 1.8kg, the addition amount of the ultrafine modified carbon powder in preparation example 4 was 1kg, and the addition amount of the ultrafine modified carbon powder in preparation example 5 was 2.5kg, and as can be seen from Table 2, as the addition amount of the ultrafine modified carbon powder was increased, the foaming rate of the foaming agent was increased and then decreased, the 1-hour settling rate of the foam obtained by foaming was decreased and then increased, and the 1-hour bleeding rate was decreased and then increased.

Compared with preparation example 2, when the foaming agent is prepared in preparation example 6, no lauroyl disodium glutamate is added, and as can be seen in combination with table 2, the addition of lauroyl disodium glutamate effectively improves the foaming multiple of the foaming agent, and reduces the 1h sedimentation rate and the 1h bleeding rate of the foam.

Compared with preparation example 2, when the foaming agent is prepared in preparation example 7, 1, 2-propylene glycol is not added, and the addition of 1, 2-propylene glycol effectively improves the foaming multiple of the foaming agent and reduces the 1h sedimentation rate and the 1h bleeding rate of the foam as can be seen by combining with table 2. The incorporation of 1, 2-propanediol can form a bilayer membrane together with anionic surfactant at the gas-liquid interface, improving the stability of the foam, but too much incorporation can affect the double layer effect of disodium lauroyl glutamate, making the foam prone to collapse, resulting in reduced stability.

Compared with preparation example 2, when the foaming agent is prepared in preparation example 8, no superfine modified carbon powder is added, and as can be seen by combining with Table 2, the addition of the superfine modified carbon powder effectively improves the foaming multiple of the foaming agent, and reduces the 1h sedimentation rate and the 1h bleeding rate of the foam.

Compared with preparation example 2, in the superfine modified carbon powder used for preparing the foaming agent in preparation example 9, butyl ether and cetyltrimethylammonium chloride are not added, and as can be seen by combining table 2, the butyl ether and the wool carbon powder are matched, so that the foaming multiple of the foaming agent is effectively improved, and the 1h sedimentation rate and the 1h bleeding rate of the foam are reduced.

Compared with preparation example 2, when the foaming agent is prepared in preparation example 10, the superfine modified carbon powder is not added, but is replaced by common commercial carbon powder, and as can be seen from the combination of table 2, the addition of the superfine modified carbon powder prepared by using the wool carbon powder effectively improves the foaming multiple of the foaming agent, and reduces the 1h sedimentation rate and 1h bleeding rate of the foam.

Examples

Example 1

S1, pouring 50kg of Portland cement and 78kg of fine aggregate into a stirrer, and dry-stirring for 2min to obtain a dry mixed material;

s2, uniformly mixing 27kg of mixing water and 0.2kg of water reducer to obtain a mixed solution, pouring the mixed solution into a stirrer, and stirring the mixed solution and the dry mixture for 5min; heating 0.4kg of pine branch tobacco tar to 130 ℃, adding the pine branch tobacco tar into a stirrer for 3 times, and continuously stirring for 15min to obtain a mixture;

s3, 5.4kg of the foaming agent prepared in the preparation example 2 and foaming water are uniformly mixed according to the volume ratio of 1:30 to obtain foaming liquid; introducing compressed air into the foaming liquid by using an air compressor to form foam;

s4, adding foam into the mixture, and stirring at a low speed for 2min at a stirring speed of 30r/min to obtain foam concrete slurry;

s5, injecting the foam concrete slurry into a mould, oscillating for 10min on a conventional vibrator with the oscillating frequency of 50Hz, filling up the mould, curing for 3 days in an environment with the temperature of 20+/-2 ℃ and the relative humidity of 65+/-1%, and curing for 28 days in an air environment with normal temperature and normal pressure to obtain the foam concrete.

Example 2

S1, pouring 50kg of Portland cement and 82kg of fine aggregate into a stirrer, and dry-stirring for 2min to obtain a dry mixed material;

s2, uniformly mixing 28kg of mixing water and 0.4kg of water reducer to obtain a mixed solution, pouring the mixed solution into a stirrer, and stirring the mixed solution and the dry mixture for 5min; heating 0.6kg of pine branch tobacco tar to 130 ℃, adding the pine branch tobacco tar into a stirrer for 3 times, and continuously stirring for 15min to obtain a mixture;

s3, 6kg of the foaming agent prepared in the preparation example 2 and foaming water are uniformly mixed according to the volume ratio of 1:40 to obtain foaming liquid; introducing compressed air into the foaming liquid by using an air compressor to form foam;

s4, adding foam into the mixture, and stirring at a low speed for 3.5min at a stirring speed of 25r/min to obtain foam concrete slurry;

Example 3

S1, pouring 50kg of Portland cement and 86kg of fine aggregate into a stirrer, and dry-stirring for 2min to obtain a dry mixed material;

s2, uniformly mixing 29kg of mixing water and 0.6kg of water reducer to obtain a mixed solution, pouring the mixed solution into a stirrer, and stirring the mixed solution and the dry mixture for 5min; heating 0.8kg of pine branch tobacco tar to 130 ℃, adding the pine branch tobacco tar into a stirrer for 3 times, and continuously stirring for 15min to obtain a mixture;

s3, 6.5kg of the foaming agent prepared in the preparation example 2 and foaming water are uniformly mixed according to the volume ratio of 1:45 to obtain foaming liquid; introducing compressed air into the foaming liquid by using an air compressor to form foam;

s4, adding foam into the mixture, and stirring at a low speed for 5min at a stirring speed of 20r/min to obtain foam concrete slurry;

Example 4

The difference from example 2 is that: the foaming agent prepared in preparation example 2 was replaced with the foaming agent prepared in preparation example 4.

Example 5

The difference from example 2 is that: the foaming agent prepared in preparation example 2 was replaced with the foaming agent prepared in preparation example 5.

Example 6

The difference from example 2 is that: the addition amount of the rosin tobacco tar is 0.4kg.

Example 7

The difference from example 2 is that: the addition amount of the rosin tobacco tar is 0.8kg.

Comparative example

Comparative example 1

The difference from example 2 is that: the foaming agent prepared in preparation example 2 was replaced with a general commercially available foaming agent.

Comparative example 2-comparative example 6

The difference from example 2 is that: the foaming agent prepared in preparation example 2 was sequentially replaced with the foaming agents prepared in preparation examples 6 to 10.

Comparative example 7

The difference from example 2 is that: pine branch tobacco tar is not added.

Comparative example 8

The difference from comparative example 7 is that: the foam concrete slurry was injected into the mold without shaking.

Comparative example 9

The difference from example 2 is that: the foam concrete slurry was injected into the mold without shaking.

Table 3 raw material tables of examples and comparative examples

Performance test

Test method

1. The method in JG/T266-2011 foam concrete is adopted to measure the length/mm of the missing edge and the falling angle of the foam concrete.

2. The dry density (kg/m 3) and 28d compressive strength (MPa) of the foam concrete were determined by the method of JG/T266-2011 foam concrete, and the test results are shown in Table 4.

Table 4 table of test results for each of examples and comparative examples

In combination with examples 1,2 and 3 and table 4, low-density high-compressive-strength foamed concrete was prepared by adjusting the addition amounts of portland cement, fine aggregate, mix water, foaming agent, water reducing agent and pine branch tobacco tar.

In the foaming agent used in example 2, example 4 and example 5, the weight ratio of the ultrafine modified carbon powder was about 14%, in the foaming agent used in example 4, the weight ratio of the ultrafine modified carbon powder was about 5.5%, and in the foaming agent used in example 5, the weight ratio of the ultrafine modified carbon powder was about 12.6%, and in Table 4, it can be seen that as the ratio of the ultrafine modified carbon powder increases, the dry density of the foamed concrete increases first and then the compressive strength increases first and then decreases.

In combination with examples 2, 6 and 7, the amount of pine branch tobacco tar added to the foam concrete prepared in example 2 was 0.6kg, the amount of pine branch tobacco tar added to the foam concrete prepared in example 6 was 0.4kg, and the amount of pine branch tobacco tar added to the foam concrete prepared in example 7 was 0.8kg, and as can be seen from Table 4, as the ratio of pine branch tobacco tar increases, the dry density of the foam concrete was decreased and then the compressive strength was increased and then decreased.

Compared with example 2, when the foam concrete is prepared in comparative example 1, the use of the foaming agent prepared in the application improves the compressive strength of the foam concrete and reduces the dry density of the foam concrete as can be seen from the combination of the common commercial foaming agents and the table 4. After the common commercial foaming agent is adopted, the foam concrete is demolded, the situation of corner falling due to the lack of edges occurs, and the length of the corner falling due to the lack of edges is more than 10mm.

In comparison with example 2, when the foam concrete is prepared in comparative example 2, the foaming agent used is not added with lauroyl disodium glutamate, and the use of lauroyl disodium glutamate in combination with Table 4 can improve the compressive strength of the foam concrete and reduce the dry density of the foam concrete.

Compared with example 2, when the foam concrete is prepared in comparative example 3, 1, 2-propylene glycol is not added into the foaming agent, and the use of 1, 2-propylene glycol improves the compressive strength of the foam concrete and reduces the dry density of the foam concrete as can be seen from the combination of table 4.

Compared with example 2, when the foam concrete is prepared in comparative example 4, the foaming agent adopted is not added with superfine modified carbon powder, the superfine modified carbon powder is formed by carbonizing waste wool fibers and adsorbing diethyl ether, and drying and crushing the powder, and the use of the superfine modified carbon powder can be seen in combination with Table 4, so that the compressive strength of the foam concrete is improved, and the dry density of the foam concrete is reduced.

Compared with example 2, when the foam concrete is prepared in comparative example 5, the superfine modified carbon powder used in the foaming agent is the powder obtained by grinding after carbonization of wool, and is not modified by butyl ether and cetyl trimethyl ammonium chloride, and as can be seen in combination with Table 4, the use of the superfine modified carbon powder improves the compressive strength of the foam concrete and reduces the dry density of the foam concrete after modification by diethyl ether and cetyl trimethyl ammonium chloride.

When the foam concrete is prepared in comparative example 6, compared with example 2, the ultrafine modified carbon powder is replaced by the common commercial carbon powder in the foaming agent, and as can be seen from the combination of table 4, the use of the ultrafine modified carbon powder improves the compressive strength of the foam concrete and reduces the dry density of the foam concrete compared with the common commercial carbon powder.

Compared with example 2, the foam concrete prepared in comparative example 7 was not added with pine branch tobacco tar, and it can be seen from Table 4 that the addition of pine branch tobacco tar increases the compressive strength of the foam concrete and decreases the dry density of the foam concrete. The foam concrete prepared in comparative example 7 was subjected to the removal of mold, and the corner was removed.

In comparison with comparative example 7, when foam concrete was prepared in comparative example 8, no shaking treatment was performed. As can be seen from the combination of table 4, the impact of the shaking treatment on the foam concrete integrity, compressive strength and dry density was reduced after addition of the rosin tobacco tar, compared to example 2, in which the shaking treatment was not performed in the preparation of the foam concrete.

The present embodiment is merely illustrative of the present application and is not intended to be limiting, and those skilled in the art, after having read the present specification, may make modifications to the present embodiment without creative contribution as required, but is protected by patent laws within the scope of the claims of the present application.

Claims

1. The foam concrete is characterized by comprising the following raw materials in parts by weight: 50 parts of silicate cement; 78-86 parts of fine aggregate; 27-29 parts of mixing water; 5.4-6.5 parts of foaming agent; 0.2-0.6 part of water reducer; 0.4-0.8 part of flow promoter; the foaming agent comprises the following raw materials in parts by weight: 10 parts of lauroyl disodium glutamate; 2-5 parts of anionic surfactant; 2.2-2.4 parts of foam stabilizer; 1-3 parts of 1, 2-propylene glycol; 1-2.5 parts of superfine modified carbon powder.

2. A foam concrete according to claim 1, characterized in that the anionic surfactant is selected from sodium dodecyl benzene sulfonate.

3. The foam concrete according to claim 1, wherein the foam stabilizer comprises polyacrylamide and hydroxypropyl methylcellulose, and the weight ratio of the polyacrylamide to the hydroxypropyl methylcellulose is (5:19) - (8:3).

4. The foam concrete according to claim 1, wherein the preparation of the ultrafine modified carbon powder comprises the steps of: mixing the powdered wool carbon, hexadecyl trimethyl ammonium chloride and butyl ether, heating in a constant-temperature water bath, intermittently stirring, treating for 30-40min, taking out the powdered wool carbon, drying at normal temperature, and grinding to obtain superfine modified carbon powder.

5. The foam concrete according to claim 4, wherein the preparation of the wool carbon powder comprises the steps of cutting waste wool products into short fibers, rinsing and airing, then treating for 20-30min at 800-850 ℃, taking out and cooling to 100-120 ℃, and grinding into powder to obtain the wool carbon powder.

6. The foam concrete according to claim 1, wherein the preparation of the foaming agent comprises the steps of: preparing a foam stabilizer and superfine modified carbon powder; uniformly mixing lauroyl disodium glutamate and anionic surfactant, and magnetically stirring at 35-45deg.C for 10-20min to obtain mixed solution; adding the foam stabilizer, the 1, 2-propylene glycol and the superfine modified carbon powder into the mixed solution, and continuously stirring for 1-2h to obtain the foaming agent.

7. The foam concrete according to claim 1, wherein the flow promoter is selected from pine branch tobacco tar, and the preparation step comprises: collecting tobacco tar burnt by pine branch.

8. A method for preparing a foam concrete according to any one of claims 1 to 7, characterized by comprising the steps of:

s1, mixing silicate cement and fine aggregate to obtain a dry mixed material;

9. The method for preparing foam concrete according to claim 8, wherein the volume ratio of the foaming agent to the foaming water is 1 (30-45).