CN115259893B

CN115259893B - Light environment-friendly building material

Info

Publication number: CN115259893B
Application number: CN202210943772.3A
Authority: CN
Inventors: 黄忠明; 吴淑武; 欧阳懂生; 欧立新; 邓伟华; 蔡松豪
Original assignee: Guangdong Guangyin Construction Co ltd
Current assignee: Guangdong Guangyin Construction Co ltd
Priority date: 2022-08-08
Filing date: 2022-08-08
Publication date: 2023-05-26
Anticipated expiration: 2042-08-08
Also published as: CN115259893A

Abstract

The invention discloses a light environment-friendly building material which mainly comprises the following raw materials in parts by weight: 5 to 45 parts of cement, 20 to 30 parts of water, 50 to 70 parts of ceramsite, 10 to 25 parts of slag, 10 to 15 parts of fly ash, 5 to 10 parts of hollow glass beads, 5 to 8 parts of superfine silica powder, 1 to 3 parts of polyether modified polycarboxylate water reducer, 0.5 to 1.0 part of foaming agent and 0.2 to 1.0 part of air entraining agent. The modified polycarboxylate water reducer prepared by the method basically does not generate extra air entrainment, can uniformly disperse cement particles, is beneficial to forming a pore structure with smaller and more uniform size inside concrete, greatly improves the compression resistance and freezing resistance of the material, and has very important significance for improving the durability of light concrete.

Description

Light environment-friendly building material

Technical Field

The invention relates to the technical field of building materials, in particular to a light environment-friendly building material.

Background

The building material is a material foundation for building production activities, has certain cultural characteristics and historical characteristics, and is continuously improved and perfected along with the continuous improvement of economic development and demands of people. The new building material is different from traditional building material, and has the functions and materials which are not reached by traditional building material, and its variety is more, and it has the excellent characteristics of light weight, high strength, heat-insulating, energy-saving, soil-saving and decorative, etc.. The novel building material not only greatly improves the basic requirements of people on house functions, promotes modernization of building construction technology, but also enables the current building to have more modern smell, and meets the continuously improved aesthetic demands and tastes of people to a certain extent, so that the novel building material can be continuously applied and popularized.

The light concrete is a porous concrete material which is prepared by uniformly mixing cement, water, optional component aggregates, seepage materials and additives according to a certain mixing ratio, uniformly mixing the mixture with fine foam prepared by a physical foaming mode of a foaming agent aqueous solution, carrying out mask building and forming on a construction site or a factory, curing under a certain condition, and hardening the porous concrete material containing a large amount of micro bubbles. The light concrete is quite different from the common concrete in the raw material composition and the production process, a large amount of foam is introduced through foaming of a foaming agent in the production process, coarse aggregate is not used, and the unique production process of the light concrete endows the light concrete with a plurality of excellent properties: (1) lightweight: in the light concrete production process, a large amount of air foam is introduced into cement slurry, and a large amount of independent closed pores are formed in the cement slurry after setting and hardening, so that the light concrete has the characteristics of low density and light weight. The density range of the lightweight concrete which is commonly used in engineering is generally less than 1000kg/m ³ It can be seen that the density is much smaller than that of the conventional civil engineering material, and if the conventional filling material is replaced by the material for filling, the additional stress of the foundation can be obviously reduced; (2) Density and Strength scalability: the dosage of materials such as foam, cement, water and the like in the lightweight concrete can be properly adjusted according to different engineering practical requirements within a certain density range, and the product meeting the requirements is obtained. The density and the compressive strength of the lightweight concrete have a certain corresponding relation, and the indirect conservation of the compressive strength meets the requirement by controlling the wet density in the construction process; (3) self-standing after curing: the light concrete uses cement as a cementing material, and has self-standing property after setting and hardening, so that the light concrete can be vertically filled, the construction operation surface is small, and the removal amount can be avoided or reduced. In addition, when the filling material is used for filling the back of the supporting structure, the supporting structure is hardly subjected to lateral pressure due to the self-standing characteristic, so that the safety of the structure is ensured, and particularly in the back backfilling of the abutment, the lateral pressure is small due to the use of light soil, and the problem of slope releasing of a conical slope of conventional filling materials can be effectively avoided; (4) good workability: the light concrete component is mainly fine grain component, does not contain coarse aggregate, has larger water cement in construction and is generally more than 0.5Therefore, the freshly mixed slurry has good fluidity, can realize the characteristics of self-leveling and self-filling compaction, has a vertical conveying height of 120m without segregation, and has a horizontal conveying distance of 800m. The lightweight concrete is generally mixed in a centralized manner on site, then is constructed in a hose accumulation and delivery mode, a temporary road is not required to be constructed for transportation, the construction occupied space is small, and only machines and raw materials are required to be placed. In addition, the light concrete uses cement as a cementing material, so that the light concrete has high strength after setting and hardening, and does not need compaction operation like conventional filling + -so that the light concrete has the characteristics of convenience and high efficiency in construction; (5) good shock resistance: the light concrete contains a large number of closed air holes, and when the earthquake waves are transmitted in the light concrete, the earthquake waves are blocked by the air holes, and a large amount of earthquake energy is consumed under the continuous reflection and transmission effects. In addition, compared with the traditional building materials, the lightweight concrete has the characteristics of small density and low elastic modulus, and can be greatly deformed under the action of earthquake load, so that most of energy is consumed, and the lightweight concrete has good earthquake resistance; (6) good sound insulation and fire resistance: a large amount of foam is introduced in the light concrete production process, and a large amount of closed holes are formed by sending the foam after coagulation and hardening, so that external noise can be effectively isolated. In addition, the raw materials used for producing the light concrete, such as cement, fly ash and the like, are nonflammable inorganic materials in terms of material components, and have good flame retardance. The characteristics enable the lightweight concrete to have great advantages in the field of heat preservation and heat insulation of buildings, and not only can insulate sound and heat, but also has good fire resistance; (7) environmental protection and economy: the main components of the foaming agent used for the lightweight concrete are ions and animal and plant proteins, no toxic substances are contained, in addition, in the production process of the lightweight concrete, a large amount of industrial waste materials such as fly ash and silicon powder discharged by power plants and steel plants, and waste materials such as slag, steel slag and coal mine stones remained by the plants can be added, thereby changing waste into valuables, reducing the pollution to the environment, reducing the production cost and having good environmental protection and economic effects.

Patent CN 112010599A discloses a modified polyphenyl granule light concrete and a preparation method thereof, and has good physical and chemical properties. The lightweight concrete comprises the following components in parts by weight: 450-500 parts of cement, 450-500 parts of cinder, 300-350 parts of fly ash, 5-8 parts of redispersible emulsion powder, 2-5 parts of polypropylene fiber, 3-5 parts of hydroxypropyl methyl cellulose, 2-4 parts of FND high-efficiency water reducer, 2-4 parts of defoamer, 20-30 parts of polyphenyl particles and 380-430 parts of water. The preparation method comprises the following steps: (10) Firstly adding water, redispersible emulsion powder, hydroxypropyl methylcellulose, FND high-efficiency water reducer and defoamer, and uniformly stirring to obtain a mixture A; (20) Adding cement and fly ash into the A, and stirring for 5-8min to obtain a mixture B; (30) And (3) adding the modified polyphenyl particles, the polypropylene fibers and the coal cinder into the B, and stirring to obtain the modified polyphenyl particle lightweight concrete.

The lightweight expansion type ultra-high performance concrete provided by the patent CN 113387646B comprises the following raw materials in parts by mass: 700-1300 parts of cementing material, 20-150 parts of additive, 500-1400 parts of aggregate, 50-250 parts of fiber and 150-250 parts of water; wherein, according to the mass portion, the cementing material includes: 500-1000 parts of ordinary Portland cement, 50-300 parts of silica fume and 100-200 parts of fly ash floating beads; the additive comprises: 5-50 parts of water reducer, 10-100 parts of expanding agent and 5-20 parts of defoaming agent, wherein the aggregate comprises the following components: 0-1300 parts of quartz sand and 10-600 parts of pre-wet lightweight aggregate. The ultra-high performance concrete prepared by the application has good working performance, mechanical performance and durability, and realizes light weight and expansion.

The water reducing agent is one of main components that play a role in concrete, and its role in light concrete is mainly represented by an influence on concrete dispersibility, slump retention and air permeability. Fluidity is the most basic, central property of concrete. The water reducer is added into the concrete, so that the dispersibility of the slurry can be obviously improved, and the workability and the homogeneity of the fresh concrete slurry in the engineering application process are improved. These effects greatly affect the internal structure of this concrete, directly affecting its resistance to freezing. The high-performance water reducer can obviously improve the dispersion performance of concrete at a lower mixing amount, and can improve the mechanical property and durability of the hardened concrete slurry. The polycarboxylate water reducer is used as a third-generation water reducer, has higher water reducing rate, low mixing amount, good dispersibility and strong slump retaining property, however, the polycarboxylate water reducer is inevitably entrained into air into slurry during mixing, which leads to the fact that the air content in the prepared concrete is increased, so that an antifoaming agent is usually added to prevent excessive air bubbles, however, the compatibility of the antifoaming agent and the polycarboxylate water reducer is poor, and a larger adding amount is required, which further leads to poor dispersibility of the antifoaming agent in the slurry. In addition, the excessive addition of the defoaming agent can seriously obstruct the effect of the air entraining agent, thereby seriously affecting the frost resistance of the concrete. Therefore, the development of the high-efficiency polycarboxylate water reducer which does not cause air entrainment and the application of the high-efficiency polycarboxylate water reducer to the preparation of light building materials have a high application prospect.

Disclosure of Invention

In view of the above-mentioned defects in the prior art, the technical problem to be solved by the invention is to provide a light environment-friendly building material with good freezing resistance and strong compression resistance and a preparation method thereof.

The durability of lightweight concrete refers to the ability of lightweight concrete to retain its safety, normal use and appearance requirements under various environmental conditions without the need to spend a significant amount of money for reinforcement treatment over a defined service life. It can be said that durability determines the service life of the engineering structure. The lightweight concrete not only bears the load effect, but also can be influenced by various environmental factors, such as temperature change, freeze thawing damage, acid-base corrosion and the like, so that the key for determining whether the durability is good is mainly the compression resistance and the freezing resistance of the material. Because of the specificity of the internal structure of the lightweight concrete, a large number of pores formed by bubbles exist in the lightweight concrete, the size and distribution of the pore size greatly influence the stability of the internal structure, which directly influences the compressive strength of the material, and a stable pore structure is also a key for improving the frost resistance of the concrete.

The polyether modified polycarboxylate water reducer in the light building material prepared by the invention has the advantages that the anionic groups such as carboxylic acid groups on the molecular structure are adsorbed to cement particles due to electrostatic attraction, and the oxazoline epoxy groups fully exert the steric hindrance effect, so that the cement particles are uniformly dispersed, the hydration reaction of cement is delayed, and the mixing water consumption of cement is reduced. In addition, as the surface activity of the prepared polyether-polycarboxylate water reducer is relatively high, the surface tension of the slurry can be well reduced, and the lower hydrophilic-hydrophobic balance value leads to better hydrophobicity, so that the dispersion of cement particles in the slurry is more facilitated. Because the oxazoline epoxy polyether is introduced into the polyether modified polycarboxylate superplasticizer, the polyether modified polycarboxylate superplasticizer has good defoaming performance, and can successfully eliminate entrained air in the mixing process. The air content in the slurry mixed by adding the polyether-polycarboxylate water reducer is basically the same as that of the mortar without any auxiliary agent, which indicates that the water reducer basically does not entrain air into the slurry, so that the use amount of the defoamer can be saved, the blocking effect among cement particles can be more uniform during mixing, the carboxylic acid group on the molecular structure of the water reducer and the cement particles are adsorbed due to electrostatic attraction, and the oxazoline epoxy group fully plays a role in steric hindrance, so that the concrete has good dispersibility, good slump retention and air entraining property, and firm and stable internal structure, thereby having good freezing resistance and compression resistance.

The technical scheme of the invention is as follows:

the light environment-friendly building material comprises the following raw materials in parts by weight: 5 to 45 parts of cement, 20 to 30 parts of water, 50 to 70 parts of ceramsite, 10 to 25 parts of slag, 10 to 15 parts of fly ash, 5 to 10 parts of hollow glass beads, 5 to 8 parts of superfine silica powder, 1 to 3 parts of polyether modified polycarboxylate water reducer, 0.5 to 1.0 part of foaming agent and 0.2 to 1.0 part of air entraining agent.

The light environment-friendly building material and the preparation method thereof comprise the following steps:

s1, spraying adsorption water in the fly ash, wherein the water quantity of the adsorption water is 30-40% of the weight of the fly ash, so as to obtain a mixed material A;

s2, uniformly mixing cement, the rest of water, ceramsite, slag, hollow glass beads and superfine silica powder to obtain a mixed material B;

and S3, uniformly mixing the mixture A, the mixture B, the foaming agent, the air entraining agent and the polyether modified polycarboxylate superplasticizer to obtain the light environment-friendly building material.

Preferably, the cement is one of silicate cement, sulfate cement and aluminate cement.

Preferably, the ceramsite is one of shale ceramsite, silt ceramsite and coal gangue ceramsite.

The foaming agent is one of rosin resin type, surfactant type, protein type foaming agent and composite foaming agent.

Preferably, the air entraining agent is one of rosin resin, alkylbenzene sulfonate and saponin.

The preparation method of the polyether modified polycarboxylate superplasticizer comprises the following steps of:

x1, weighing 2 to 3 weight parts of methoxy polyethylene glycol and 1.4 to 2.0 weight parts of polymethacrylic acid, adding into 2 to 3 weight parts of water, heating to 80 to 90 ℃ and stirring for 1 to 2 hours, vacuumizing the system to remove water, then heating to 150 to 180 ℃, preserving heat for 4 to 6 hours, cooling the grafted product to-80 to-70 ℃ after the reaction is finished, and adding 6 to 8 weight parts of water to dilute the pH to 2 to 3 to obtain polyethylene glycol-polycarboxylic acid polymer solution;

and X2, weighing 0.2 to 0.3 weight part of oxazoline epoxy polyether, adding 0.3 to 0.4 weight part of polyethylene glycol-polycarboxylic acid polymer solution into 2 to 3 weight parts of water, heating to 80 to 90 ℃ and stirring for 1 to 2 hours, vacuumizing the system to remove water, then heating to 180 to 190 ℃, preserving heat for 4 to 6 hours, cooling to room temperature after the reaction is finished, and adding 30 weight percent of NaOH aqueous solution to adjust the pH to 7 to obtain the polyether modified polycarboxylic acid water reducer.

The preparation method of the oxazoline epoxy polyether comprises the following steps:

weighing 5-6 parts by weight of glycolic acid, adding 7-8 parts by weight of isobutanol amine into 100-120 parts by weight of dimethylbenzene, heating to 150-170 ℃, stirring for 14-16 hours, and concentrating under reduced pressure to remove dimethylbenzene to obtain a white solid;

weighing 0.6-1 part by weight of tetrabutylammonium bisulfate, adding 4-5 parts by weight of the white solid obtained in the step Y1 into 30-40 parts by weight of 40wt% NaOH aqueous solution, stirring for 30-40 min at 0-5 ℃, adding 4-5 parts by weight of epichlorohydrin, stirring for 18-20 h, heating to room temperature, adding 30-40 parts by weight of ethyl acetate, extracting, separating liquid, and concentrating an organic phase until the organic phase is dried to obtain yellow solid;

weighing 0.1-0.2 part by weight of phosphazene base, adding 0.5-1 part by weight of benzyl alcohol into 2-5 parts by weight of toluene, stirring at 0-5 ℃ for 30-40 min, adding the yellow solid in the step Y2, stirring for 4-6 h, and concentrating to remove the solvent after the polymerization reaction is finished to obtain the oxazoline epoxy polyether.

Compared with the prior art, the invention has the beneficial effects that:

(1) The polyether modified polycarboxylate water reducer prepared by the invention has the advantages that the anionic groups such as carboxylic acid groups on the molecular structure and cement particles are adsorbed due to electrostatic attraction, so that the oxazoline epoxy polyether fully plays a role in steric hindrance, the cement particles are uniformly dispersed, the hydration reaction of cement is delayed, and the mixing water consumption of cement is reduced;

(2) In addition, as the surface activity of the prepared polyether-polycarboxylate water reducer is relatively high, the surface tension of the slurry can be well reduced, and the lower hydrophilic-hydrophobic balance value leads to better hydrophobicity, so that the dispersion of cement particles in the slurry is more facilitated. The oxazoline epoxy polyether side chain is introduced into the polyether modified polycarboxylate water reducer, so that the polyether modified polycarboxylate water reducer has good defoaming performance, and the entrained air can be successfully eliminated in the mixing process, so that the use amount of the defoaming agent can be saved, the blocking effect among cement particles can be more uniform during mixing, the carboxylic acid group on the molecular structure of the water reducer and the cement particles are adsorbed due to electrostatic attraction, the oxazoline epoxy polyether fully plays a steric hindrance role, and the effects jointly lead to good dispersibility, slump retention and air entraining performance of the concrete, and the internal structure is solid and stable, so that the concrete has good freezing resistance and compression resistance;

(3) The ultrafine silica powder added into the concrete can strengthen the closure of gas gaps in the concrete, so that the internal pores are smaller and more uniform, and the used slag, coal ash and the like are recycled materials, thereby being environment-friendly.

Detailed Description

The technical scheme of the present invention will be described in detail by means of specific examples, which should be explicitly set forth for illustration, but should not be construed as limiting the scope of the present invention.

The parameters of partial raw materials in the embodiment of the invention are as follows:

portland cement, P.O.52.5, fineness (45 μm) screen residue: 5, yunnan is a chemical industry.

Shale ceramsite, model: a2020921-88, specification: 500 grade Hubei Huiteng light aggregate.

Slag, model: RX-240, moisture content 0.1%, mineral products of the Mingxiang county.

Hollow glass bead, model: 3m s60hs, density: 0.60g/cm ³ External electric international chemical industry.

Superfine silica powder, CG-1250 mesh, water content of 0.1%, silicon material in Jiangsu.

Sodium dodecyl benzene sulfonate, model: TD-228, pH=5-7, shenzhen Tadala chemical industry.

Polycarboxylate water reducer, model: SP-409, the gas content is less than or equal to 2.7%, liaoning Kelong fine chemical industry.

Phosphazene base, 0.8mol/L n-hexane solution, and Ala-dine.

Methoxy polyethylene glycol, MPEG-2000, hydroxyl number: 25.5-31 mg KOH/g, jiangsu sea-An petrochemical industry.

Composite foaming agent, model: HTW-1, henan Huatai building material.

The organosilicon defoamer used in the examples is a ceramic organosilicon defoamer, model: AFE-3168, content: 30wt% of new Suzhou An Tefu material.

Polymethacrylic acid, cat No.: AL670786017520, shandong ao Li Long chemical industry.

Comparative example 1

A light environment-friendly building material and a preparation method thereof comprise the following steps:

s1, spraying 3kg of adsorption water into 10kg of fly ash, and uniformly mixing to obtain a mixed material A;

s2, uniformly mixing 45kg of silicate cement, 22kg of water, 50kg of shale ceramsite, 10kg of slag, 8kg of hollow glass beads and 5kg of superfine silica powder to obtain a mixture B;

and S3, uniformly mixing the mixture A, the mixture B, 0.5kg of composite foaming agent, 0.8kg of sodium dodecyl benzene sulfonate and 2kg of polycarboxylate water reducer to obtain the light environment-friendly building material.

Example 1

and S3, uniformly mixing the mixture A, the mixture B, 0.5kg of composite foaming agent, 0.8kg of sodium dodecyl benzene sulfonate and 2kg of polyether modified polycarboxylate superplasticizer to obtain the light environment-friendly building material.

The preparation method of the polyether modified polycarboxylate superplasticizer comprises the following steps:

x1, weighing 3kg of methoxy polyethylene glycol and 1.4kg of polymethacrylic acid, adding into 3L of water, heating to 80 ℃ and stirring for 1h, vacuumizing the system to remove water, then heating to 150 ℃, preserving heat for 4h, cooling the grafted product to-80 ℃ after the reaction is finished, and then adding 6L of water to dilute the pH to 3 to obtain polyethylene glycol-polycarboxylic acid polymer solution;

and X2, weighing 0.2kg of oxazoline epoxy polyether, adding 0.3kg of polyethylene glycol-polycarboxylic acid polymer solution into 2L of water, heating to 80 ℃, stirring for 1h, vacuumizing the system to remove water, then heating to 180 ℃, preserving heat for 6h, cooling to room temperature after the reaction is finished, and adding 30wt% of NaOH aqueous solution to adjust the pH to 7 to obtain the polyether modified polycarboxylic acid water reducer.

weighing 5kg of glycolic acid and 7kg of isobutanol amine, adding into 12.5L of dimethylbenzene, heating to 170 ℃ and stirring for 16 hours, concentrating at-0.9 MPa and 45 ℃ after the reaction is finished to remove dimethylbenzene to obtain white solid;

weighing 0.6kg of tetrabutylammonium bisulfate, adding 4kg of white solid obtained in the step Y1 into 30kg of 40wt% NaOH aqueous solution, stirring for 30min at 0 ℃, adding 4kg of epichlorohydrin, stirring for 18h, heating to room temperature, adding 30kg of ethyl acetate for extraction, separating liquid, and concentrating an organic phase at-0.9 MPa and 45 ℃ until the organic phase is dried to obtain yellow solid;

weighing 0.1kg of phosphazene base, adding 0.6kg of benzyl alcohol into 3kg of toluene, stirring at 0 ℃ for 30min, adding the yellow solid in the step Y2, stirring for 6h, concentrating at-0.9 MPa and 45 ℃ after the polymerization reaction is finished, and removing the solvent to obtain the oxazoline epoxy polyether.

Example 2

s3, uniformly mixing the mixture A, the mixture B, 0.5kg of composite foaming agent, 0.8kg of sodium dodecyl benzene sulfonate, 2kg of polycarboxylate superplasticizer and 0.5kg of organosilicon defoamer to obtain the light environment-friendly building material.

Example 3

s2, uniformly mixing 45kg of silicate cement, 22kg of water, 50kg of shale ceramsite, 10kg of slag and 8kg of hollow glass beads to obtain a mixture B;

Test example 1

The method for testing the freezing resistance of the light concrete is not clear in China at present, but the method for testing the freezing resistance of the concrete material is mature and can be used for a certain reference. There are two methods for concrete freezing resistance test in the existing "test method Standard for ordinary concrete Long-term Properties and durability" (GB/T50082-2009): slow freezing and fast freezing. The invention refers to a slow freezing method for experiments, which comprises the following specific steps: light concrete slurry was prepared according to the mix ratio specification and poured into molds of dimensions 100mm x 100mm as required for a total of 4 sets of 5 specimens each. The sample is removed from the mold after being cured for 1 day in the room, and then the sample is moved to a curing room for standard curing. And when the curing age is 24 days, taking out the test piece, numbering the test piece by using a paint pen, then soaking the test piece in water at 20 ℃, taking out the test piece from the water when the test piece reaches the curing age of 28 days, immediately wiping off superfluous water on the surface by using a wet rag after checking the appearance, immediately weighing, and wrapping the test piece tightly after weighing. And (3) placing the wrapped test piece into a freezer, performing a freezing test, reducing the temperature by 10 ℃ every 1h until the temperature is reduced to minus 20 ℃, and keeping the constant temperature. And after the freezing is finished, immediately taking out the sample from the freezing box, putting the sample into water with the temperature of 20 ℃ for melting, and after a few minutes, peeling the preservative film from the sample after the surface ice layer is melted, wherein the sample is melted in the water continuously for 12 hours. After a prescribed number of freeze-thaw cycle tests, the samples were weighed and the mass loss rate was calculated.

TABLE 1 freezing resistance test results table

When the outside temperature of the lightweight concrete is low, water in the small holes in the lightweight concrete can freeze to generate ice expansion pressure, when the lightweight concrete expands to be larger than the tensile strength of the hole wall, the hole wall is damaged, the temperature rises, frozen water melts, and part of precipitate is carried with the frozen water, so that the phenomenon is called freeze thawing damage of the lightweight concrete. The freezing resistance of lightweight concrete refers to the property of resisting repeated freezing and thawing cycle actions without damage under the state of water absorption saturation. When the pores in the concrete are large and the pore distribution is uneven, the pore walls in the concrete are thinner, the pores are easy to damage in the freeze thawing process, and the absorbed moisture is more, while the polyether modified polycarboxylate water reducer added in the embodiment 1 can reduce the water content of the cement during mixing, on the other hand, even and stable tiny pores are formed in the concrete with the air entraining agent, the internal pore distribution is even, and the sealing performance of gas gaps in the concrete is better due to the addition of superfine silica powder, so that the inside of the concrete is firm and stable and is not easy to damage during freeze thawing. Although the polycarboxylate water reducer used in comparative example 1 can reduce the water content in cement to some extent, air entrained during mixing can cause oversized air hole pores in the concrete, which can cause water to easily enter the gaps during freezing and thawing, and the structure of the concrete is damaged from the inside due to freezing at low temperature, so that the freezing resistance performance is poor.

Test example 2

The concrete prepared in the comparative examples and examples was subjected to a compressive strength test, the test method was operated with reference to autoclaved aerated concrete Performance test method (GB/T11969-2020), the concrete was mixed, and the mixed concrete was put into a cubic test mold having dimensions of 100 mm. Times.100 mm, and then the test mold was placed on a vibration table to vibrate, and the vibration was continued until the surface of the test mold was free of slurry and free of significant large bubbles. After the test piece is molded and smeared, the surface is covered by a plastic film, the test piece is kept stand for 2 days in an environment with the temperature of 20 ℃ and the relative humidity of more than or equal to 50 percent, and the test piece is immediately placed into a curing chamber with the temperature of 20 ℃ and the relative humidity of more than or equal to 95 percent for curing after the test piece is coded and unpacked. Before the test, the bottom plate and the top plate of the compressor are wiped clean by a dry towel, a sample is placed in the center of the bottom plate of the electronic universal tester, the tester is started, the compression direction is perpendicular to the pouring direction of the sample, the base is adjusted to enable the top surface of the sample to be parallel to the surface of the pressing plate, so that the sample can be fully contacted in the compression process, when the sample is nearly contacted, a program is started, the loading of the press at the speed of 2kN/s is ensured, the deformation condition of the sample is observed at any time in the compression process until the sample is damaged, the test is stopped, and test data are stored. Each compression experiment has 3 samples, the compressive strength of each sample is calculated according to formula 1, and the average value of 3 test results is taken as the strength value of the group of samples.

f _cu =f/a-1

f _cu Compressive strength of the test specimen in MPa;

f, breaking load, wherein the unit is kN;

a-area of pressure applied to sample, mm ² 。

Table 2 compressive strength test values

Experimental protocol	Compressive Strength/MPa
		Comparative example 1	38.6
Example 1	43.2
		Example 2	37.4
Example 3	36.7

The water reducing agent is one of main components that play a role in concrete, and its role in light concrete is mainly represented by an influence on concrete dispersibility, slump retention and air permeability. Fluidity is the most basic, central property of concrete. The water reducer is added into the concrete, so that the dispersibility of the slurry can be obviously improved, and the workability and the homogeneity of the fresh concrete slurry in the engineering application process are improved. These effects greatly affect the internal structure of the concrete and thus the compressive strength of the concrete. As can be seen from table 2, the concrete material prepared in example 1 has the best compressive strength, probably due to the fact that the prepared polyether-polycarboxylate water reducer has relatively high surface activity, which can well reduce the surface tension of the slurry, and the lower hydrophilic-hydrophobic balance value leads to better hydrophobicity and is more beneficial to the dispersion of cement particles in the slurry. The carboxylic acid group on the molecular structure of the water reducer and cement particles are adsorbed due to electrostatic attraction, and the oxazoline epoxy polyether fully plays a role in steric hindrance, so that the concrete has good dispersibility, slump retention and air entraining property, and a solid and stable internal structure, so that the concrete has good compression resistance.

Test example 3

The concrete prepared in the comparative example and the example is subjected to air inclusion amount measurement, and the concrete test method comprises the following steps: 2kg of the uncured concrete slurry prepared in each example was placed in a stirrer and stirred uniformly, then placed in a container, the balance was filled with water by vibration compaction, the water was poured out after filling, and the volume fraction of the poured water in the container was calculated to be the air content in the material, and the specific test results are shown in table 3.

TABLE 3 air entrainment quantity test results Table

Experimental protocol	Air content/vol%
		Comparative example 1	14.5
Example 1	4.1
		Example 2	4.3
Example 3	4.2

As can be seen from the test results in Table 3, the air entrainment amount of the concrete prepared in the comparative example is obviously higher than that of examples 1-3, while the entrainment amount of the polyether modified polycarboxylate superplasticizer used in example 1 is obviously smaller, and the effect of the defoamer used in example 2 is basically the same, probably because the oxazoline epoxy polyether side chain is introduced into the polyether modified polycarboxylate superplasticizer, the foam-removing agent has good foam-removing performance, and the entrained air can be successfully eliminated in the mixing process, so that the foam-removing agent is not only beneficial to the formation of the internal pore structure of the concrete, but also can reduce the use of the defoamer and reduce the cost.

Claims

1. The light environment-friendly building material is characterized by mainly comprising the following raw materials in parts by weight: 5-45 parts of cement, 20-30 parts of water, 50-70 parts of ceramsite, 10-25 parts of slag, 10-15 parts of fly ash, 5-10 parts of hollow glass beads, 5-8 parts of superfine silica powder, 1-3 parts of polyether modified polycarboxylate water reducer, 0.5-1.0 part of foaming agent and 0.2-1.0 part of air entraining agent;

x1, weighing 2-3 parts by weight of methoxy polyethylene glycol and 1.4-2.0 parts by weight of polymethacrylic acid, adding into 2-3 parts by weight of water, heating to 80-90 ℃ and stirring for 1-2 hours, vacuumizing the system to remove water, heating to 150-180 ℃, preserving heat for 4-6 hours, cooling the grafted product to-80 to-70 ℃ after the reaction is finished, and adding 6-8 parts by weight of water to dilute the pH to 2-3 to obtain polyethylene glycol-polycarboxylic acid polymer solution;

x2, weighing 0.2-0.3 part by weight of oxazoline epoxy polyether, adding 0.3-0.4 part by weight of polyethylene glycol-polycarboxylic acid polymer solution into 2-3 parts by weight of water, heating to 80-90 ℃ and stirring for 1-2 hours, vacuumizing the system to remove water, then heating to 180-190 ℃, preserving heat for 4-6 hours, cooling to room temperature after the reaction is finished, and adding 30wt% of NaOH aqueous solution to adjust pH to 7 to obtain the polyether modified polycarboxylic acid water reducer;

and (3) weighing 0.1-0.2 part by weight of phosphate, adding 0.5-1 part by weight of benzyl alcohol into 2-5 parts by weight of toluene, stirring at 0-5 ℃ for 30-40 min, adding the yellow solid in the step (Y2), stirring for 4-6 h, and concentrating to remove the solvent after the polymerization reaction is finished to obtain the oxazoline epoxy polyether.

2. A lightweight, environmentally friendly building material as set forth in claim 1, wherein: the cement is one of silicate cement, sulfate cement and aluminate cement.

3. A lightweight, environmentally friendly building material as set forth in claim 1, wherein: the ceramsite is one of shale ceramsite, silt ceramsite and coal gangue ceramsite.

4. A lightweight, environmentally friendly building material as set forth in claim 1, wherein: the foaming agent is one of rosin resin type, surfactant type, protein type foaming agent and composite foaming agent.

5. A lightweight, environmentally friendly building material as set forth in claim 1, wherein: the air entraining agent is one of rosin resin, alkyl benzene sulfonate and saponin.

6. The method for preparing a light environment-friendly building material according to any one of claims 1 to 5, comprising the following steps:

s1, spraying adsorption water in the fly ash, wherein the water quantity of the adsorption water is 30-40% of the weight of the fly ash, and obtaining a mixed material A;