阅读说明：本技术 一种轻质高强陶粒混凝土及其制备方法和应用 (Light high-strength ceramsite concrete and preparation method and application thereof ) 是由 姚华彦 吴启一 陈传明 代领 王静峰 *** 刘文博 代义磊 田野 陈刚 于 2019-10-14 设计创作，主要内容包括：本发明涉及一种轻质高强陶粒混凝土及其制备方法和应用,涉及建筑材料领域,由以下组分按重量份数组成：胶凝材料400～530份；粗骨料420～460份；细骨料650～850份；外加剂6.8～21份；水160～220份；所述粗骨料为粉煤灰陶粒；所述细骨料由炉渣与砂子组成；所述外加剂包括聚羧酸减水剂与增强剂。本发明以超细改性粉煤灰、水泥与活性硅微粉为胶凝材料；以炉渣与河砂为细骨料；以粉煤灰陶粒为粗骨料,制备轻质化高强预制构件,有效的解决了由于陶粒密度小而导致的陶粒混凝土分层的问题,制备的陶粒混凝土强度高,便于实际施工操作,且有效利用固废,益于环境保护。(The invention relates to a light high-strength ceramsite concrete and a preparation method and application thereof, which relate to the field of building materials and comprise the following components in parts by weight: 400-530 parts of a cementing material; 420-460 parts of coarse aggregate; 650-850 parts of fine aggregate; 6.8-21 parts of an additive; 160-220 parts of water; the coarse aggregate is fly ash ceramsite; the fine aggregate is composed of slag and sand; the admixture comprises a polycarboxylic acid water reducing agent and a reinforcing agent. The invention takes superfine modified fly ash, cement and active silica micropowder as cementing materials; taking slag and river sand as fine aggregate; the lightweight high-strength prefabricated part is prepared by taking the fly ash ceramsite as the coarse aggregate, the problem of ceramsite concrete layering caused by small ceramsite density is effectively solved, and the prepared ceramsite concrete has high strength, is convenient for actual construction operation, effectively utilizes solid wastes and is beneficial to environmental protection.)

1. The light high-strength ceramsite concrete is characterized by comprising the following components in parts by weight:

the coarse aggregate is fly ash ceramsite; the fly ash ceramsite is prepared by uniformly mixing fly ash, an excitant, a cosolvent and a foaming agent, granulating and then curing;

the fine aggregate is composed of slag and sand; the volume of the slag in the fine aggregate accounts for 10-50%;

the admixture comprises a polycarboxylic acid water reducing agent.

2. The light high-strength ceramsite concrete according to claim 1, wherein the concrete comprises: 445-490 parts of a cementing material; the cementing material is prepared from 390-420 parts of cement; 40-50 parts of superfine modified fly ash; 0-20 parts of active silicon micro powder; the sand is at least one of river sand, river sand and machine-made sand.

3. The lightweight high-strength ceramsite concrete according to claim 2, wherein: 15-20 parts of active silicon micro powder.

4. The light high-strength ceramsite concrete according to claim 1, wherein the concrete comprises: the mass ratio of the fly ash, the excitant, the cosolvent and the foaming agent is 200: 6: 3, the excitant is prepared from sodium hydroxide and semi-hydrated desulfurized gypsum according to the mass ratio of 3: 5, the cosolvent is anhydrous sodium sulphate, and the foaming agent is aluminum paste.

5. The light high-strength ceramsite concrete according to claim 1, wherein the concrete comprises: the admixture further comprises a reinforcing agent, wherein the doping amount of the reinforcing agent is 1.8-2.1 wt% of the cementing material, and the doping amount of the polycarboxylic acid water reducing agent is 1.7-2.0 wt% of the cementing material.

6. The light high-strength ceramsite concrete according to claim 5, wherein the concrete comprises: the main component of the reinforcing agent is calcium silicate hydrate sol particles; the grade of the polycarboxylate superplasticizer is at least one of ZX-II type Hefezhong, ST-01YW of Shandong Linyi water reducer production plant or Wuhanhuaxuan HX-YZJ 01.

7. The light high-strength ceramsite concrete according to claim 1, wherein the concrete comprises: the slag is bottom ash discharged from the bottom of a boiler of a coal-fired power plant, and the microstructure of the slag is a molten vitreous body; the grain size of the slag is less than 5 mm; the slag consists of the following components: 4 to 20 weight percent of ferric oxide, 15 to 40 weight percent of silicon oxide, 3 to 30 weight percent of aluminum oxide, 2 to 10 weight percent of calcium oxide and 1 to 5 weight percent of magnesium oxide.

8. The method for preparing the light-weight high-strength ceramsite concrete according to any one of claims 1 to 7, which is characterized by comprising the following steps of:

s1, pre-wetting the coarse aggregate, and airing to a surface drying and internal saturated water absorption state;

s2, mixing and stirring the coarse aggregate and the fine aggregate treated by the S1 for 30-90S;

s3, adding a cementing material into the mixed material treated in the S2, and stirring for 30-90S;

s4, slowly adding an aqueous solution prepared by adding water into the polycarboxylic acid water reducing agent and the reinforcing agent into the mixed material obtained after the S3 mixing, and stirring for 30-90S to obtain the light high-strength ceramsite concrete;

the mass concentration of the water solution prepared from the polycarboxylate superplasticizer and the reinforcing agent is 3.6-13%.

9. The application of the lightweight high-strength ceramsite concrete according to any one of claims 1 to 7, which comprises the following steps: pouring the light high-strength ceramsite concrete into a mould which is already placed with the steel bars; after the concrete is flattened, a vibrating rod is used for primary vibration, and after the primary vibration, the concrete is vibrated by a mould platform until no obvious sinking, starching and no air bubbles appear; detecting the thickness by using a thickness scale, and adjusting the thickness at the deviation position; after adjustment, the light high-strength member is obtained through secondary vibration, normal-temperature pre-curing, twice press polishing, normal-pressure steam curing, mold stripping and natural curing in sequence.

10. The application of the lightweight high-strength ceramsite concrete according to claim 9, is characterized in that: the first calendering of the two-time calendering is carried out at the initial setting, the second calendering is carried out at the final setting, and the steam curing is carried out in a steam curing kiln.

Technical Field

The invention relates to the field of building materials, in particular to light high-strength ceramsite concrete and a preparation method and application thereof.

Background

With the continuous expansion and development of urban buildings, the ecological environment increasingly provides an agenda, the assembly type buildings conform to the environmental development trend of China, and the development trend of green buildings is increasingly highlighted.

At this stage, most projects use precast concrete units suitable for residential structures with small spans. The structural forms of high-rise buildings, super high-rise buildings and the like in the building industry, bridge engineering, railway engineering and hydraulic engineering in China are rapidly developed, the structural forms have the problems of dead weight, span and the like, the technical requirement on prestressed concrete construction is high, and the modern engineering construction faces new challenges. Under the background, ceramsite concrete with the characteristics of light weight, high strength and the like gradually becomes a main trend of application and development in the field of concrete.

In the existing preparation process of ceramsite concrete, only ceramsite is mixed with river sand, but the density of the ceramsite is lower than that of the stirred cement mortar, the ceramsite is easy to float upwards in the preparation process, the homogeneity of the concrete is reduced, and even the phenomenon of layering and segregation can be generated, so that the use and popularization of the ceramsite concrete are influenced.

The slag is used as waste after combustion in a power plant, and is stacked in a planned ash piling field after power generation in a thermal power plant. The power plant slag of the ash piling field of the thermal power plant occupies a large amount of land, and the raised dust seriously pollutes the environment, is not beneficial to environmental protection and has high maintenance cost; in addition, the conventional ceramsite concrete has a small proportion of fly ash, so that a light high-strength ceramsite concrete, a preparation method and application thereof are needed to be provided to improve the problems.

Disclosure of Invention

In order to solve the technical problem that the light high-strength ceramsite concrete material is difficult to prepare in the prior art, the invention aims to provide light high-strength ceramsite concrete.

In order to realize the purpose of the invention, the invention adopts the following technical scheme: the light high-strength ceramsite concrete comprises the following components in parts by weight:

the coarse aggregate is fly ash ceramsite;

the fine aggregate is composed of slag and sand; the volume of the slag in the fine aggregate accounts for 10-50%;

the admixture comprises a polycarboxylic acid water reducing agent.

Preferably, the cementing material is 445-490 parts; the cementing material is prepared from 390-420 parts of cement; 40-50 parts of superfine modified fly ash; 0-20 parts of active silicon micro powder; the sand is at least one of river sand, river sand and machine-made sand.

Preferably, the active silicon powder is 15-20 parts.

Preferably, the preparation method of the fly ash ceramsite comprises the following steps: uniformly mixing the fly ash, the excitant, the cosolvent and the foaming agent, granulating, and curing to obtain fly ash ceramsite; the mass ratio of the fly ash, the excitant, the cosolvent and the foaming agent is 200: 6: 3, the excitant is prepared from sodium hydroxide and semi-hydrated desulfurized gypsum according to the mass ratio of 3: 5, the cosolvent is anhydrous sodium sulphate, and the foaming agent is aluminum paste.

Preferably, the admixture further comprises a reinforcing agent, the mixing amount of the reinforcing agent is 1.8-2.1 wt% of the cementing material, and the mixing amount of the polycarboxylate superplasticizer is 1.7-2.0 wt% of the cementing material.

Preferably, the main component of the reinforcing agent is calcium silicate hydrate sol particles; the grade of the polycarboxylate superplasticizer is at least one of ZX-II type Hefezhong, ST-01YW of Shandong Linyi water reducer production plant or Wuhanhuaxuan HX-YZJ 01.

Preferably, the slag is bottom ash discharged from the bottom of a coal-fired power plant boiler, and the microstructure of the slag is molten vitreous body; the grain size of the slag is less than 5 mm; the slag consists of the following components: 4 to 20 weight percent of ferric oxide, 15 to 40 weight percent of silicon oxide, 3 to 30 weight percent of aluminum oxide, 2 to 10 weight percent of calcium oxide and 1 to 5 weight percent of magnesium oxide.

The second purpose of the invention is to provide a preparation method of the lightweight high-strength ceramsite concrete, which comprises the following steps:

the preparation method of the light high-strength ceramsite concrete comprises the following steps:

s1, pre-wetting the coarse aggregate, and airing to a surface drying and internal saturated water absorption state;

s2, mixing and stirring the coarse aggregate and the fine aggregate treated by the S1 for 30-90S;

s3, adding a cementing material into the mixed material treated in the S2, and stirring for 30-90S;

s4, slowly adding an aqueous solution prepared by adding water into the polycarboxylic acid water reducing agent and the reinforcing agent into the mixed material obtained after the S3 mixing, and stirring for 30-90S to obtain the light high-strength ceramsite concrete;

the mass concentration of the water solution prepared from the polycarboxylate superplasticizer and the reinforcing agent is 3.6-13%.

The third purpose of the invention is to provide an application of the lightweight high-strength ceramsite concrete:

the application of the light high-strength ceramsite concrete comprises the following steps: pouring the light high-strength ceramsite concrete into a mould which is already placed with the steel bars; after the concrete is flattened, a vibrating rod is used for primary vibration, and after the primary vibration, the concrete is vibrated by a mould platform until no obvious sinking, starching and no air bubbles appear;

the thickness scale is used for thickness detection, the position where the concrete needs to be increased or decreased is properly adjusted, secondary re-vibration is carried out after the adjustment is finished, the vibration time is not less than 10 seconds, the concrete is guaranteed not to leak vibration, and the situation that the vibration is not in place is avoided;

leveling the prefabricated part, entering a standing pre-curing stage after leveling, and covering the prefabricated part by using a curing shed when the room temperature is lower than 20 ℃;

the calendering adopts two times of calendering, the first time of calendering is carried out during initial setting, and the second time of calendering is carried out during final setting;

and pushing the member into a steam curing kiln, continuing steam curing at 60 ℃ for 12h, removing the mold, transferring to a storage yard, and performing natural curing for 28d to obtain the light-weight high-strength member.

The invention has the beneficial effects that: (1) according to the preparation method, the fly ash ceramsite is pre-wetted and dried until the surface of the fly ash ceramsite is dry and the interior of the fly ash ceramsite is saturated and absorbs water, so that the self weight is increased, the fly ash ceramsite is prevented from floating upwards due to light density, the water content in the fly ash ceramsite is increased, and the condition that the fly ash ceramsite excessively absorbs water to cause uneven distribution in a concrete system during concrete stirring is prevented. The pre-wetted fly ash ceramsite is pre-mixed with the fine aggregate, so that part of the fine aggregate can be filled into a porous structure on the surface of the fly ash ceramsite under the action of mechanical stirring, the self weight of the fly ash ceramsite is further increased, and the fly ash ceramsite is further prevented from floating upwards. The pre-wetted fly ash ceramsite, the fine aggregate and the cementing material are pre-mixed, so that active substances such as tricalcium aluminate and the like in the cementing material and a small amount of free water on the surface of the fly ash ceramsite after saturated water absorption are subjected to hydration reaction in advance, and a 'gel shell' is formed together with the fine aggregate to coat the outer surface of the fly ash ceramsite, so that the free water in the fly ash ceramsite can be prevented from running out, the weight of the fly ash ceramsite is constant, and the solidified concrete can keep toughness due to the contained water.

(2) The slag has certain active ingredients, the particle size is small, the particle shape is spherical and irregular blocky particles, the slag can be well filled into the pores of the aggregate, the compactness of the ceramsite concrete is increased, the durability of the ceramsite concrete is improved, and the density of cement mortar can be reduced by doping the slag into the concrete, so that the density difference between the cement mortar and the ceramsite is reduced, the homogeneity of the concrete is improved, and the volume weight of the concrete is further reduced. The slag is applied to the ceramsite concrete, so that the pollution of the slag to the environment can be relieved, and the working performance of the concrete can be improved. The fine aggregate is added with the furnace slag, so that the non-renewable natural sand resource can be effectively saved, the harm of solid waste to the environment is reduced, the land is saved, the environment is protected, the economic benefit and the social effect are good, and the environmental protection policy of the current country is met.

(3) Compared with the traditional fly ash which accounts for only 20-30% of the concrete, the solid waste such as fly ash and furnace slag accounts for as high as 50-80% of the concrete system, so that the utilization rate of the solid waste such as fly ash and furnace slag is greatly improved, and a new way for comprehensively utilizing the solid waste in the field of building materials is developed.

(4) In the invention, calcium silicate hydrate sol particles are introduced as a reinforcing agent, and crystal nuclei are provided in the concrete hydration process, so that the nucleation barriers are eliminated, the formation of C-S-H gel is promoted, the effect of enhancing the concrete strength is achieved, and the mechanical property of the fly ash ceramsite concrete is greatly improved.

(5) In addition, the active silica powder is added in the invention to further fill capillary pores in the set cement, so that hydration reaction is promoted, the strength of the set cement part in the final concrete is further increased, and the overall mechanical property is further improved.

(6) The fly ash ceramsite used in the ceramsite concrete is activated by the activator, so that the volcanic ash effect of the fly ash can be fully exerted, the self cylinder pressure strength of the obtained ceramsite is far higher than that of common shale or clay ceramsite, the final mechanical strength of the ceramsite concrete prepared from the ceramsite concrete can be higher than C30, and compared with the condition that the common shale ceramsite concrete can only be used as a light partition board, the fly ash ceramsite concrete disclosed by the invention can be used for a load-bearing structure, and the application range of the ceramsite concrete is expanded.

Detailed Description

The technical solution of the present invention will be described in further detail with reference to specific embodiments.

Preparing the fly ash ceramsite: 200 parts of fly ash, 6 parts of exciting agent, 6 parts of cosolvent and 3 parts of foaming agent are uniformly mixed, added into a granulator for granulation and molding, and maintained in a standard curing chamber for 28 days. The river sand is class II river sand meeting GB/T14684-2011; the river sand is class II river sand meeting GB/T14684-2011; the machine-made sand is class II machine-made sand meeting GB/T14684-2011. The fineness modulus of the river sand is 1.4, and the apparent density is 2700kg/m ³Bulk density 1360kg/m ³Porosity 41.5%; the sand degree modulus of the machine is 3.3, and the apparent density is 2690kg/m ³Bulk density 1620kg/m ³Porosity 38.7%; the fineness modulus of the river sand is 1.2, and the apparent density is 2410kg/m ³Bulk density 1490kg/m ³Porosity 42.3%;

the cement is P.O 425 cement or P.II525 portland cement meeting the GB175-2007 requirements; the superfine modified fly ash is grade I or II fly ash prepared by Gaodi environmental protection company; the active silica micropowder meets the GB/T27690-2011 requirement.

The slag is bottom ash discharged from the bottom of a boiler of a coal-fired power plant, and the microstructure of the slag is a molten vitreous body; the grain size of the slag is less than 5 mm; the slag consists of the following components: 4 to 20 weight percent of ferric oxide, 15 to 40 weight percent of silicon oxide, 3 to 30 weight percent of aluminum oxide, 2 to 10 weight percent of calcium oxide, 1 to 5 weight percent of magnesium oxide and 3 to 10 weight percent of loss on ignition.

The 3d compressive strength of the cement is 32MPa, the 28d compressive strength is 52MPa, the 3d flexural strength is 5.8MPa, and the 28d flexural strength is 7.8 MPa;

the superfine modified fly ash has fineness of 12%, loss on ignition 3.8%, water requirement 94% and water content 03% and density 2.54g/cm ³Activity 82% in 28 days;

specific surface area of slag 595m ²Kg, density 2.84g/cm ³The flow ratio is 97 percent, and the water content is 0.2 percent;

the polycarboxylate superplasticizer is a Zhongxing ZX-II type polycarboxylate superplasticizer for fertilizer synthesis;

the reinforcing agent mainly comprises calcium silicate hydrate sol particles.

Preparing a light high-strength member: pouring the light high-strength ceramsite concrete into a mould which is already placed with the steel bars; after the concrete is roughly flattened, primarily vibrating by using a vibrating bar, and vibrating by using a mould platform after primary vibrating until the concrete does not obviously sink, begins to be pulped and does not generate bubbles; the thickness scale is used for thickness detection, the position where the concrete needs to be increased or decreased is properly adjusted, secondary re-vibration is carried out after the adjustment is finished, the vibration time is not less than 10 seconds, the concrete is guaranteed not to leak vibration, and the situation that the vibration is not in place is avoided; leveling the prefabricated part, entering a standing pre-curing stage after leveling, and covering the prefabricated part by using a curing shed when the room temperature is lower than 20 ℃; the calendering adopts two times of calendering, the first time of calendering is carried out during initial setting, and the second time of calendering is carried out during final setting; and pushing the member into a steam curing kiln, continuing steam curing at 60 ℃ for 12h, removing the mold, transferring to a storage yard, and performing natural curing for 28d to obtain the light-weight high-strength member.