CN113912352B

CN113912352B - Green light thermal insulation mortar

Info

Publication number: CN113912352B
Application number: CN202111376538.9A
Authority: CN
Inventors: 李静
Original assignee: Shandong Shuangneng Building Materials Co ltd
Current assignee: Shandong Shuangneng Building Materials Co ltd
Priority date: 2021-11-19
Filing date: 2021-11-19
Publication date: 2023-07-07
Anticipated expiration: 2041-11-19
Also published as: CN113912352A

Abstract

The invention discloses green light thermal insulation mortar, which comprises the following raw materials in parts by weight: 10-20 parts of cement, 5-10 parts of fly ash, 30-50 parts of phosphogypsum, 10-20 parts of vitrified micro bubble, 20-50 parts of river sand, 0.05-0.1 part of thickener, 0.05-0.1 part of water reducer, 0.05-0.1 part of reinforcing agent and 30-60 parts of water. The invention comprehensively utilizes two industrial wastes of the fly ash and the phosphogypsum, respectively uses the two industrial wastes as fine aggregate and main components filled in the mortar, and is supplemented with river sand and vitrified micro bubbles, so that the raw materials are reasonably prepared; not only reduces the consumption of cement, but also has good filling density among filling aggregates for capillary pores, and improves the performance of mortar.

Description

Green light thermal insulation mortar

Technical Field

The invention belongs to the field of building materials, and particularly relates to green light thermal insulation mortar.

Background

The urban process in China is rapidly developed, the building industry is rapid, and the problems of high building resource consumption and high building energy consumption are increasingly highlighted. For a building, the consumption can be divided into the consumption of the construction process and the consumption in the use process, and the consumption caused by the use is long-term relative to the consumption of the construction. The consumption in the use process mainly consists in energy loss caused by lighting, warm keeping and temperature reduction. Therefore, it is necessary to use the construction waste as a raw material for building construction and to reduce energy consumption in the use of the building.

In order to achieve comfortable working and living conditions, most buildings regulate the indoor temperature through air conditioning, heating, etc. Therefore, the heat insulation performance and the heat preservation performance of the building are improved, and the energy consumption loss is greatly reduced. The heat-insulating mortar is a building plastering material which is prepared by using low-density inorganic particles with heat insulation and heat preservation performance as light aggregate through cementing materials and other various composite additives, has insulating performance, is lighter than common plastering mortar, and can be directly applied to wall surfaces. The heat-insulating mortar applied to the surface of the building can effectively reduce the energy loss in the use process of the building.

CN 109485342A discloses a kind of kenaf stalk light anti-cracking thermal insulation mortar, the mortar includes cementing material, sand, kenaf stalk fiber, fly ash floating bead, kenaf stalk core, wherein the kenaf stalk core is used as substitute vitrified microbead, which can increase thermal resistance of kenaf stalk anti-cracking thermal insulation mortar and reduce cost, and the kenaf stalk fiber is used as substitute polyvinyl alcohol fiber, which can significantly improve cracking resistance and toughness of kenaf stalk anti-cracking thermal insulation mortar; compared with the treatment method of directly adding the straw into the mortar, the method for respectively adding the kenaf straw core and the kenaf straw fiber into the mortar can more fully utilize the kenaf straw and improve the mechanical property and the heat preservation property of the mortar; the anti-cracking performance is outstanding, the thermal resistance of the wall body can be obviously increased, the heat conductivity coefficient is reduced when the anti-cracking agent is smeared on the surface of the wall body, the energy saving, environment protection and waste utilization of the building are realized, and the anti-cracking agent has good environmental benefit, economic benefit and social benefit.

CN 109942267A discloses a gypsum-based composite light thermal insulation mortar, which comprises the following components in parts by weight: 60-80 parts of gypsum powder, 1-2 parts of polyphenyl particles, 10-15 parts of vitrified microbeads, 5-10 parts of cement, 1-2 parts of redispersible emulsion powder, 0.2-0.6 part of water-retaining agent, 0.2-0.6 part of gypsum retarder, 0.3-0.8 part of water reducer, 0.2-0.8 part of polypropylene fiber and 60-80 parts of water. The invention uses vitrified microbeads and polyphenyl particles to select proper particle size distribution for mixing, then combines with semi-hydrated gypsum, has simple preparation mode, reduces the consumption of cementing materials, has low cost, reduces dry density, has high crack resistance, low shrinkage deformation, high ductility and good workability, and has good self-compaction property and excellent heat preservation property.

CN 109160786A discloses a heat-preserving light mortar based on refuse incinerator slag solidification and a preparation method thereof, wherein the main components and corresponding parts by weight are as follows: 10-20 parts of cementing material, 15-35 parts of filling aggregate, 0.1-0.5 part of modifier, 0.1-0.5 part of additive, 0.1-0.5 part of reinforcing fiber, 2-4 parts of foaming agent and 3 parts of water-material ratio: 6, preparing a base material; wherein the filling aggregate comprises 10-20 parts of garbage incinerator slag and 5-15 parts of heat preservation aggregate. The preparation method comprises the following steps: (1) Placing slag in the open air for natural ventilation, and loading the slag into a ball mill for ball milling, wherein the volume ratio of ball milling steel balls to slag to be milled is 1:3, a step of; (2) Adding the cementing material and the filling aggregate into a stirrer, adding water, stirring, controlling the temperature to be 50 ℃, stopping heating by the stirrer, naturally cooling to room temperature, adding other components, continuously stirring, pouring into a tool for 1d after stirring, and demoulding for maintenance. According to the invention, firstly, environmental protection evaluation is carried out on the environmental safety of the waste incineration slag, the modified slag is fully utilized as filling aggregate, and the solid waste resource utilization is carried out.

Although, in the prior art, thermal insulation mortar is prepared by comprehensively utilizing some biological wastes and industrial wastes, and the system research of improving the performance of the mortar by utilizing two or more industrial wastes and adding additives is relatively less.

Disclosure of Invention

In view of the defects of the prior art, the technical problem to be solved by the invention is to provide green light thermal insulation mortar.

In order to achieve the above purpose, the invention provides green light thermal insulation mortar, which comprises the following raw materials in parts by weight: 10-20 parts of cement, 5-10 parts of fly ash, 30-50 parts of phosphogypsum, 10-20 parts of vitrified micro bubble, 20-50 parts of river sand, 0.05-0.1 part of thickener, 0.05-0.1 part of water reducer, 0.05-0.1 part of reinforcing agent and 30-60 parts of water.

The fly ash is the main solid waste discharged from the coal-fired power plant, and is fine ash collected from the flue gas after the coal combustion, and as the particles of the fly ash are mostly microbeads and have smaller particle sizes, the fly ash can play roles of filling, lubricating, deflocculating, dispersing water and the like, the water consumption of a mixing system can be reduced, and the use of a large amount of cement and fine aggregate can be saved by adding and mixing the fly ash.

Phosphogypsum is industrial waste residue discharged from the wet-process phosphoric acid production in the phosphorus chemical industry, and the purity of calcium sulfate dihydrate in phosphogypsum can reach more than 90%, however, compared with natural gypsum, phosphogypsum also contains various components such as non-decomposed phosphorite, residual phosphoric acid, calcium fluoride, acid insoluble matters, organic matters, radioactive substances, rare earth elements and the like. These substances have an adverse effect on the recycling of phosphogypsum, which must be pretreated before use. Some researches and practices show that the phosphogypsum can be heated to convert eutectic phosphorus into inert pyrophosphate to volatilize organic matters, and the phosphogypsum has the performance equivalent to that of a gypsum product prepared from the same-grade natural gypsum after being neutralized and calcined.

The vitrified microbeads are inorganic mineral raw materials, are irregular spherical particles, have surface vitrification and closure, smooth luster and an internal porous cavity structure, and mainly comprise silicon oxide, aluminum oxide and calcium oxide, and have a ball vitrification rate and a floating rate of more than 95 percent and a water absorption rate of less than 50 percent. The surface can generate particles with higher strength during production, has better physical and chemical properties and higher durability, has good functions of heat insulation, sound absorption, heat preservation, water absorption and the like, belongs to A-level heat preservation materials, can be used as filling aggregate and heat preservation and heat insulation materials in various projects, and is a novel environment-friendly high-quality inorganic material.

Graphene is a carbon material in which sp2 hybridized connected carbon atoms are closely stacked into a single-layer two-dimensional honeycomb lattice structure, and has excellent physical and chemical properties. The addition of the graphene can reduce the internal porosity of the cement, promote the hydration process of the cement and influence the form of hydration products. The graphene is doped into the cement mortar, so that the critical aperture of the mortar is reduced, the microcrack blocking effect is achieved, the mechanical strength of the mortar is effectively improved, and the water permeability resistance of the mortar is improved.

Alpha-trehalose is a non-reducing disaccharide consisting of two glucose molecules. The structural formula is alpha-D-glucopyranosyl-alpha-D-glucopyranoside, which is usually present as a dihydrate, has no reducibility, low hygroscopicity and very good stability to heat and acid and alkali.

Preferably, the cement is ordinary Portland cement or Portland cement.

The phosphogypsum is calcined for 1-3 hours at 800-1000 ℃ before being used, then crushed and sieved by a 300-500 mesh sieve, and phosphogypsum powder under the sieve net is collected.

The grain composition of the river sand is medium sand.

The thickener is at least one of methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose and hydroxypropyl methyl cellulose.

The water reducer is at least one of naphthalene sulfonate water reducer, melamine water reducer, lignin sulfonate and polycarboxylic acid high-efficiency water reducer.

The reinforcing agent is at least one of graphene, alpha-trehalose and graphene/alpha-trehalose compound.

The graphene is single-layer or few-layer graphene, the sheet diameter is 0.5-5 mu m, the thickness is 0.8-1.2 nm, and the single-layer rate is 80%.

The inventor finds that graphene and alpha-trehalose are used together, and the graphene-based high specific surface area can be used as a template, so that more hydration products are accumulated on the surface of the graphene-based high specific surface area, the hydration process is accelerated, and the morphology of the hydration products is influenced; the alpha-trehalose has unique film forming effect, and forms a film structure on the surface of aggregate in the mortar, so that the formed hydration product is more stable.

Further preferably, the mass ratio of graphene to alpha-trehalose in the reinforcing agent is 1: (2-4).

However, the dispersibility of graphene in a mortar system has a defect, so that the effect of enhancing the mortar performance can be achieved by adding more graphene in an effective action range. In addition, if the local content of graphene in the system is large, the graphene with large specific surface area can attract hydration products, so that the hydration products are locally gathered in a large amount, and uneven and discontinuous pores exist in the test piece, so that the stress of the test piece is uneven, and the strength and the waterproof performance of mortar can be reduced. According to the invention, the graphene is modified, and functional substances are introduced, so that good dispersion of the graphene in a mortar system is realized, and the effect of the graphene and additives (thickening agent and water reducing agent) in the system is enhanced; the influence of graphene on the morphology adjustment of the hydration product is more remarkable, the action of aggregate in the system and the added additive is promoted, and the actions are beneficial to improving the performance of the mortar.

Further preferably, the graphene is modified, and the specific steps are as follows: the method comprises the following specific steps: adding 1-2 parts by weight of graphene into 100-200 parts by weight of absolute ethyl alcohol at 20-40 ℃, and performing ultrasonic treatment for 30-60 min at the ultrasonic power of 50-200W and the frequency of 20-130 kHz to obtain a graphene suspension a; adding 2-5 parts by weight of 1-ethyl-3-methylimidazolium bis (trifluoromethyl sulfonyl) imine salt into a suspension a stirred at a stirring speed of 300-500 r/min, heating the suspension a to 50-60 ℃, carrying out reflux reaction for 5-10 h under stirring, centrifuging for 20-30 min at 8000-10000 r/min, collecting insoluble substances, and freeze-drying at-45 to-55 ℃ for 24-36 h to obtain the modified graphene.

More preferably, the mass ratio of the modified graphene to the alpha-trehalose in the reinforcing agent is 1: (2-4).

Most preferably, the enhancer is a graphene/alpha-trehalose compound, and the preparation method comprises the following steps: adding 1-2 parts by weight of graphene into 100-200 parts by weight of absolute ethyl alcohol at 20-40 ℃, and performing ultrasonic treatment for 30-60 min at the ultrasonic power of 50-200W and the frequency of 20-130 kHz to obtain a graphene suspension a; adding 2-8 parts by weight of alpha-trehalose and 2-5 parts by weight of 1-ethyl-3-methylimidazolium bis (trifluoromethyl sulfonyl) imide salt into a suspension a stirred at a stirring speed of 300-500 r/min, heating the suspension a to 50-60 ℃, carrying out reflux reaction for 5-10 h under stirring, centrifuging for 20-30 min at 8000-10000 r/min to collect insoluble matters, and then freeze-drying for 24-36 h at-45-55 ℃ to obtain the graphene/alpha-trehalose compound.

The invention also provides a preparation method of the mortar, which comprises the following steps:

s1, weighing all raw materials according to a formula;

s2, mixing and stirring cement, fly ash, phosphogypsum, river sand, a water reducing agent, a reinforcing agent and part of water for 10-20 min at the rotating speed of 50-100 r/min to obtain a mixed system A;

and S3, adding the thickener, the residual water and the vitrified micro bubbles into the mixed system A obtained in the step S2, and mixing and stirring for 10-20 min at the rotating speed of 50-100 r/min to obtain the green light thermal insulation mortar.

Preferably, part of the water in the step S2 is 60-70% of the total water weight.

The invention has the beneficial effects that:

(1) The invention comprehensively utilizes two industrial wastes of the fly ash and the phosphogypsum, respectively uses the two industrial wastes as fine aggregate and main components filled in the mortar, and is supplemented with river sand and vitrified micro bubbles, so that the raw materials are reasonably prepared; not only reduces the consumption of cement, but also has good filling density among filling aggregates for capillary pores, and improves the performance of mortar.

(2) The invention uses the synergistic effect of the graphene and the alpha-trehalose to enhance the strength of the mortar, reduces the apparent density of the mortar, and avoids the defects of high brittleness, large shrinkage and empty cracking of the thermal insulation mortar.

(3) The preparation method is simple, comprehensively utilizes two industrial wastes of the fly ash and the phosphogypsum, and is beneficial to industrial production.

Detailed Description

Introduction of part of the raw materials used in the examples of the present invention:

the specification of cement and ordinary Portland cement is P.O42.5, and various indexes are compounded with national standards.

The fly ash belongs to class II fly ash, is collected in a Wuhan Qingshan power plant and comprises the following components:

phosphogypsum is collected in the technology limited company of the Wuhan middle east phosphorus industry in the Wuhan city of Hubei province, and the components are as follows:

vitrified microbeads purchased from Xinyang Jinhua lan mining Co.

River sand, common river sand belongs to grade I sand, is classified into medium sand in particle size, and is purchased from Hebei Bao-Ting engineering construction company.

The polycarboxylic acid high-efficiency water reducer is purchased from Chengdu City Rong-Wei technology Co.

Graphene, single-layer or few-layer graphene, has a sheet diameter of 0.5-5 μm and a thickness of 0.8-1.2 nm, and has a single-layer rate of 80%, and is purchased from pioneer nanotechnology limited company.

Alpha-trehalose was purchased from Shandong Jianchuan Biotechnology Co.

The remaining unrecited raw materials are all conventional in the art, on the order of technical grade or more.

Example 1

A green light thermal insulation mortar comprises the following preparation methods:

s1, weighing 10kg of cement, 5kg of fly ash, 50kg of phosphogypsum, 15kg of vitrified micro bubbles, 25kg of river sand, 0.1kg of hydroxypropyl methylcellulose, 0.08kg of polycarboxylic acid high-efficiency water reducer, 0.05kg of graphene and 40kg of water;

s2, mixing and stirring cement, fly ash, phosphogypsum, river sand, a water reducing agent, graphene and part of water for 15min at the rotating speed of 80r/min to obtain a mixed system A;

and S3, adding hydroxypropyl methylcellulose, residual water and vitrified micro bubbles into the mixed system A obtained in the step S2, and mixing and stirring for 15min at the rotating speed of 60r/min to obtain the green light thermal insulation mortar.

The phosphogypsum in the step S1 is phosphogypsum powder which is calcined at 850 ℃ for 2 hours, naturally cooled to 25 ℃ and then passes through a 325-mesh screen, and is collected under the screen;

the portion of water described in step S2 is 60% of the total water mass.

Example 2

s1, weighing 10kg of cement, 5kg of fly ash, 50kg of phosphogypsum, 15kg of vitrified micro bubbles, 25kg of river sand, 0.1kg of hydroxypropyl methylcellulose, 0.08kg of polycarboxylic acid high-efficiency water reducer, 0.05kg of alpha-trehalose and 40kg of water;

s2, mixing and stirring cement, fly ash, phosphogypsum, river sand, a water reducing agent, alpha-trehalose and part of water for 15min at the rotating speed of 80r/min to obtain a mixed system A;

the portion of water described in step S2 is 60% of the total water mass.

Example 3

s1, weighing 10kg of cement, 5kg of fly ash, 50kg of phosphogypsum, 15kg of vitrified micro bubbles, 25kg of river sand, 0.1kg of hydroxypropyl methylcellulose, 0.08kg of polycarboxylic acid high-efficiency water reducer, 0.01kg of graphene, 0.04kg of alpha-trehalose and 40kg of water;

s2, mixing and stirring cement, fly ash, phosphogypsum, river sand, a water reducing agent, graphene, alpha-trehalose and part of water for 15min at the rotating speed of 80r/min to obtain a mixed system A;

the portion of water described in step S2 is 60% of the total water mass.

Example 4

s1, weighing 10kg of cement, 5kg of fly ash, 50kg of phosphogypsum, 15kg of vitrified micro bubbles, 25kg of river sand, 0.1kg of hydroxypropyl methylcellulose, 0.08kg of polycarboxylic acid high-efficiency water reducer, 0.01kg of modified graphene, 0.04kg of alpha-trehalose and 40kg of water;

s2, mixing and stirring cement, fly ash, phosphogypsum, river sand, a water reducer, modified graphene, alpha-trehalose and part of water for 15min at the rotating speed of 80r/min to obtain a mixed system A;

the preparation method of the modified graphene in the step S1 comprises the following steps: adding 1g of graphene into 200g of absolute ethyl alcohol at 25 ℃, and performing ultrasonic treatment for 30min at the ultrasonic power of 100W and the frequency of 50kHz to obtain a graphene suspension a; 5g of 1-ethyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide salt is added into a suspension a stirred at a stirring speed of 300r/min, the temperature of the suspension a is raised to 100 ℃, reflux reaction is carried out for 8h under stirring, insoluble substances are collected by centrifugation at 8000r/min for 20min, and then freeze drying is carried out at-55 ℃ for 24h, so that the modified graphene is obtained.

The portion of water described in step S2 is 60% of the total water mass.

Example 5

s1, weighing 10kg of cement, 5kg of fly ash, 50kg of phosphogypsum, 15kg of vitrified micro bubbles, 25kg of river sand, 0.1kg of hydroxypropyl methylcellulose, 0.08kg of polycarboxylic acid high-efficiency water reducer, 0.05kg of graphene/alpha-trehalose compound and 50kg of water;

the preparation method of the graphene/alpha-trehalose compound in the step S1 comprises the following steps: adding 1g of graphene into 200g of absolute ethyl alcohol at 25 ℃, and performing ultrasonic treatment for 30min at the ultrasonic power of 100W and the frequency of 50kHz to obtain a graphene suspension a; adding 4g of alpha-trehalose and 5g of 1-ethyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide salt into a suspension stirred at a stirring speed of 300r/min, increasing the temperature of the suspension a to 60 ℃, carrying out reflux reaction for 10h under stirring, centrifuging at 8000r/min for 30min to collect insoluble substances, and then freeze-drying at-55 ℃ for 24h to obtain a graphene/alpha-trehalose compound;

the portion of water described in step S2 is 60% of the total water mass.

Comparative example 1

A green light thermal insulation mortar is prepared by the same method as in example 1, except that graphene is not added.

Test example 1 measurement of thermal conductivity of mortar

The thermal conductivity of the mortar determines the thermal insulation performance of the mortar. The thermal conductivity coefficient of the mortar is measured according to the standard GB/T10294-2008 for measuring the steady-state thermal resistance and related characteristics of heat insulating materials. Transferring the mortar into a test die, forming and curing to prepare a test piece with the size of 300mm multiplied by 30mm, and drying in a constant-temperature oven until the weight is not changed any more; and measuring the heat conductivity coefficient of the test piece by using a double-plate heat conductivity coefficient meter. The thermal conductivity results are shown in table 1.

Table 1 thermal conductivity of mortar test pieces

	Thermal conductivity W/(m.k)
		Comparative example 1	0.114
Example 1	0.116
		Example 2	0.108
Example 3	0.94
		Example 4	0.92
Example 5	0.083

From the results of table 1, it can be seen that the thermal conductivity of example 1, to which graphene is added, is improved over that of comparative example 1, probably because graphene is unevenly dispersed in the mortar system, agglomerated graphene causes a large amount of cement hydration products to locally aggregate, so that non-uniform and discontinuous pores exist in the test piece, and glass beads can be buried, gaps among mortar aggregates of different grades are reduced, solid-gas interface contact is reduced, and the effects enhance the thermal conductivity of the mortar. The thermal conductivity of example 2 with added alpha-trehalose is reduced, probably because alpha-trehalose can form a membranous structure on the surface of the cement hydration products, and the hydroxyl groups of the alpha-trehalose enhance the repulsive force between hydration products generated at early stage, so that the formed hydration products have a more stable structure, and tiny pores are introduced between the hydration products; many tiny solid-gas interfaces are added, and the main mode for heat transfer is radiation heat transfer between the gas-solid interfaces, so that the heat conduction capacity of the material is weakened. The thermal conductivity of the example 3 added with graphene and alpha-trehalose is relatively obviously reduced, which is probably because the electrostatic repulsive action of the alpha-trehalose enhances the dispersibility of the graphene in a mortar system, so that early hydration products generated by taking the graphene as a template are distributed more uniformly, and tiny pores between hydration products with excellent mechanical properties of the graphene and aggregate are firmer; the stability of the interface is improved while the tiny solid-gas interface is increased, and the thermal conductivity number of the mortar is further reduced by the synergistic effect of the graphene and the alpha-trehalose.

In example 4, the thermal conductivity of the mortar added with the modified graphene and the alpha-trehalose is also obviously reduced relatively, probably because the 1-ethyl-3-methylimidazolium bis (trifluoromethyl sulfonyl) imide salt modified graphene has larger specific surface area, the dispersibility of the graphene in a mortar system is promoted, more hydration products can be attracted to form in the graphene, the electrostatic repulsive effect of the alpha-trehalose also increases a plurality of tiny solid-gas interfaces, the heat transmission path is longer, and the heat transfer is delayed. Example 5, with the addition of the graphene/α -trehalose complex, has the lowest coefficient of thermal conductivity, probably because the graphene/α -trehalose complex has stronger film-forming properties to stabilize hydration products templated with graphene, allowing more hydration products to deposit on the graphene surface; the graphene/alpha-trehalose compound enables hydration products to form a non-agglomerated and interconnected sheet structure, and the structure enables aggregate to be tightly connected and introduces a tiny solid-gas interface, so that a heat transmission path is longer, heat is not easy to be emitted from the structure, and heat transfer is further delayed.

Test example 2 fluidity of mortar

The fluidity of mortar refers to the property of the mortar flowing under the action of dead weight or external force, and generally, the higher the fluidity, the better the mortar fluidity. Fluidity test reference standard GB/T2419-2005 method for measuring fluidity of Cement mortar. The results are shown in Table 2.

TABLE 2 fluidity of mortar

From the test results of table 2, it can be seen that the mortar of example 5 added with the graphene/α -trehalose complex has the best fluidity, which may be that the components in the graphene/α -trehalose complex act together so that the free water in the hydration product is easily released, thereby improving the fluidity of the mortar.

Test example 3 strength and Dry apparent Density test of mortar

The compressive strength of the mortar was measured by transferring the mortar into a test mold according to the standard GB/T17671-1999 "cement mortar Strength test method", molding and curing the mortar to prepare a test piece having a size of 40 mm. Times.40 mm. Times.160 mm, and testing the compressive strength of the test piece after curing for 7 days.

Measurement of test piece dry Density reference standard GBT5486-2008, inorganic hard Heat insulation product test method, test piece is put into a constant temperature oven at 110 ℃, dried until the quality is not changed, and the Density is calculated.

TABLE 3 compressive Strength and Dry apparent Density of mortars

	Compressive Strength/MPa	Dry density/kg.m ^-3
			Comparative example 1	10.31	425
Example 1	12.34	446
			Example 2	12.56	406
Example 3	14.83	383
			Example 4	15.26	379
Example 5	17.32	366

From the test results of the compressive strength in table 3, it can be seen that the addition of graphene and alpha-trehalose can improve the compressive strength of the mortar, probably because the graphene promotes the hydration process of cement, reduces the critical aperture of the mortar, and improves the mechanical strength of the mortar; the alpha-trehalose easily forms a membranous structure on the surface of aggregate in the mortar, so that the stability of hydration products is enhanced. In addition, the graphene and the alpha-trehalose have good synergistic effect, the alpha-trehalose increases the dispersibility of the graphene in a mortar system, stabilizes hydration products generated on the surface of the graphene, reduces the use amount of the graphene and improves the compressive strength. The modified graphene and the compressive strength of the mortar are also remarkably improved, and the probability is that the existence of the surface functional groups enables the graphene to be dispersed more uniformly in the mortar system, and more hydration products can be attracted to form in the graphene, so that the aggregate is tightly connected. The mortar added with the graphene/alpha-trehalose compound in the embodiment 5 has the highest compressive strength, which is probably the hydration product with the modified graphene as a template, wherein the film forming property of the graphene/alpha-trehalose compound can stabilize, so that more hydration products are deposited on the surface of the graphene, the electrostatic interaction is stronger, the hydration products form a non-agglomerated and interconnected sheet structure, and the structure ensures that aggregate connection is tight and stable, and the compressive strength of the mortar is further improved.

From the dry density test results in table 3, it can be seen that example 5, with the addition of the graphene/α -trehalose complex, had the lowest dry density, which is probably that the graphene/α -trehalose complex formed a non-agglomerated, interconnected sheet structure of the hydration product, which was finer, with many micro-voids present, thus significantly reducing the dry density of the mortar test block.

Claims

1. The green light thermal insulation mortar is characterized by comprising, by weight, 10-20 parts of cement, 5-10 parts of fly ash, 30-50 parts of phosphogypsum, 10-20 parts of vitrified micro bubbles, 20-50 parts of river sand, 0.05-0.1 part of a thickening agent, 0.05-0.1 part of a water reducer, 0.05-0.1 part of a reinforcing agent and 30-60 parts of water;

the reinforcing agent is modified graphene and alpha-trehalose, and the mass ratio of the reinforcing agent to the alpha-trehalose is 1: (2-4) mixing to obtain; or, the reinforcing agent is a graphene/alpha-trehalose compound;

the preparation method of the modified graphene comprises the following steps: adding 1-2 parts by weight of graphene into 100-200 parts by weight of absolute ethyl alcohol at 20-40 ℃, and performing ultrasonic treatment for 30-60 min at the ultrasonic power of 50-200W and the frequency of 20-130 kHz to obtain a graphene suspension a; adding 2-5 parts by weight of 1-ethyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide salt into a suspension a stirred at a stirring speed of 300-500 r/min, heating the suspension a to 50-60 ℃, carrying out reflux reaction for 5-10 h under stirring, centrifuging for 20-30 min at 8000-10000 r/min to collect insoluble substances, and freeze-drying at-45 to-55 ℃ for 24-36 h to obtain modified graphene;

the preparation method of the graphene/alpha-trehalose compound comprises the following steps: adding 1-2 parts by weight of graphene into 100-200 parts by weight of absolute ethyl alcohol at 20-40 ℃, and performing ultrasonic treatment for 30-60 min at the ultrasonic power of 50-200W and the frequency of 20-130 kHz to obtain a graphene suspension a; adding 2-8 parts by weight of alpha-trehalose and 2-5 parts by weight of 1-ethyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide salt into a suspension a stirred at a stirring speed of 300-500 r/min, heating the suspension a to 50-60 ℃, carrying out reflux reaction for 5-10 h under stirring, centrifuging at 8000-10000 r/min for 20-30 min to collect insoluble substances, and then freeze-drying at-45 to-55 ℃ for 24-36 h to obtain the graphene/alpha-trehalose compound.

2. The green light thermal insulation mortar of claim 1, wherein the fly ash is class ii fly ash.

3. The green light thermal insulation mortar of claim 1, wherein phosphogypsum is calcined for 1-3 hours at 800-1000 ℃ before being used, then crushed and screened by a 300-500 mesh sieve, and phosphogypsum powder under the screen is collected.

4. The green light thermal insulation mortar of claim 1, wherein the thickener is at least one of methylcellulose, carboxymethylcellulose, hydroxyethylcellulose, and hydroxypropylmethyl cellulose.

5. The green light thermal insulation mortar of claim 1, wherein the water reducer is at least one of naphthalene sulfonate water reducer, melamine water reducer, lignin sulfonate and polycarboxylic acid high efficiency water reducer.

6. The green light thermal insulation mortar of claim 1, wherein the graphene is single-layer or few-layer graphene, the sheet diameter is 0.5-5 μm, the thickness is 0.8-1.2 nm, and the single-layer rate is 80%.

7. The method for preparing the green light thermal insulation mortar according to any one of claims 1 to 6, comprising the following steps:

s1, weighing all raw materials according to a formula;

8. The method for preparing green light thermal insulation mortar according to claim 7, wherein the partial water in the step S2 is 60-70% of the total water weight.