An alkali-activity inhibitor composed of a polymer-modified nanomaterial composite, and its preparation method and application

Abstract

The present invention relates to an alkali-activity inhibitor composed of polymer-modified nanomaterials and a preparation method and application thereof, and relates to the technical field of aggregate alkali-activity inhibitors. The alkali-activity inhibitor includes material A and material B. By weight, material A includes the following components: 57 to 87 parts of inorganic nano-active materials and 0 to 30 parts of mineral admixtures. By weight, material B includes the following components: 0.02 to 0.05 part of surfactant, 1 to 2 parts of redispersible latex powder, 0.1 to 0.2 part of hydroxypropyl methyl cellulose ether, 0.1 to 0.2 part of lignin fiber, and 5 to 10 parts of permeable crystallization components. The present invention optimizes the compatibility of the aggregate alkali-activity inhibitor from seven components in two material packages through the method of orthogonal design, and formulates an alkali-activity inhibitor suitable for the technical characteristics and construction of pebble concrete, providing key core technical elements and safety guarantees for the rapid construction of pebble projects.

Description

Technical Field

[0001] The present invention relates to the technical field of aggregate alkali activity inhibitors, and particularly relates to an alkali activity inhibitor compounded with a polymer-modified nanomaterial, a preparation method thereof, and an application thereof. Background Art

[0002] Concrete is the building material with the largest consumption, the widest application range, and the most economical in contemporary architecture, and has gone through an extraordinary journey of nearly 100 years. With the rapid expansion of infrastructure construction (such as: hydraulic and hydropower projects and pumped storage power plant workshops, dams, tunnels and other hydraulic structures; construction projects; nuclear power projects; large bridges and tunnels; marine port projects; military projects; highway projects; high-speed railway projects), the usage of concrete materials is becoming more and more extensive, especially the demand for the main components of concrete materials, cement and aggregates, is increasing accordingly.

[0003] However, due to the special construction geographical location of the project, the aggregate, which accounts for the largest component of concrete materials, must be mined and processed near the project site or use local materials to avoid the confusion of long-distance transportation. In this context, the aggregates in some collection sites will inevitably encounter potential alkali-activity reaction situations, which requires special engineering and technical measures to modify or improve the concrete materials, and adding an aggregate alkali-activity reaction inhibitor to the concrete has become one of the necessary engineering measures for modification or improvement.

[0004] In the construction field, concrete is undoubtedly the cornerstone of modern architecture, but this widely used material also hides a hard-to-detect crisis, which is known as the "cancer" of concrete in the industry. This rather scary name is actually the "alkali-aggregate reaction ARR". The alkali-aggregate activity reaction is a problem that takes a long time to emerge. Some appear in several years, or even more than a decade or longer, and are often easily ignored, but it has laid a foreshadowing for the overall durability of concrete buildings and the safety of structures.

[0005] There are three conditions for the occurrence of aggregate alkali-activity reaction: First, the total alkali content in the concrete raw materials such as cement, admixture, admixture and water seriously exceeds the standard. The generally accepted total alkali content at home and abroad is ≤ 3 Kg / m 3 , exceeding this value may cause potential alkali-aggregate activity reaction; second, there are a considerable number of potential active components in the aggregate; third, a humid environment, with sufficient moisture or wet air entering the concrete.

[0006] At present, those skilled in the art are all conducting research in these three aspects. Some want to block the entry of moisture or humidity into the concrete, some want to avoid using aggregates with potential alkali-aggregate activity reaction, and some are to limit the total alkali content in the concrete. However, these starting points all have their respective one-sidedness and limitations, and it is difficult to comprehensively solve and respond to them. Summary of the Invention

[0007] To solve the above problems, the present invention provides an alkali - activity inhibitor composed of polymer - modified nanomaterials, and its preparation method and application.

[0008] In the first aspect, the present invention provides an alkali - activity inhibitor composed of polymer - modified nanomaterials, and the alkali - activity inhibitor includes Material A and Material B;

[0009] By weight, Material A includes the following components:

[0010] 57 - 87 parts of inorganic nano - active material and 0 - 30 parts of mineral admixture;

[0011] By weight, Material B includes the following components:

[0012] 0.02 - 0.05 parts of surfactant, 1 - 2 parts of redispersible latex powder, 0.1 - 0.2 parts of hydroxypropyl methyl cellulose ether, 0.1 - 0.2 parts of lignin fiber, and 5 - 10 parts of permeable crystallization component.

[0013] Further, the weight ratio of Material A to Material B is (80 - 90):(10 - 20).

[0014] Further, the inorganic nano - active material is inorganic nano - SiO₂.

[0015] Further, the mineral admixture is zeolite powder with a particle size of 200 - 300 mesh.

[0016] Further, the surfactant is propylene glycol.

[0017] Further, the redispersible latex powder is a copolymer of vinyl versatate.

[0018] Further, the permeable crystallization component is composed of sodium carbonate, citric acid, tartaric acid, sodium metasilicate, and calcium stearate in a weight ratio of (7 - 8):(1 - 2):(1 - 2):(1 - 2):(0.2 - 0.3).

[0019] In the second aspect, the present invention provides a preparation method of the alkali - activity inhibitor composed of polymer - modified nanomaterials according to any item in the first aspect, and the preparation method includes the following steps:

[0020] Weigh the inorganic nano - active material and the mineral admixture in proportion and then mix them to obtain Material A;

[0021] Weigh the surfactant, redispersible latex powder, hydroxypropyl methyl cellulose ether, lignin fiber, and permeable crystallization component in proportion and then mix them to obtain Material B.

[0022] In a third aspect, the present invention provides an application of an alkali-activity inhibitor compounded with a polymer-modified nanomaterial according to any one of the first and second aspects in the preparation of concrete.

[0023] In a fourth aspect, the present invention provides a river pebble concrete, which includes an alkali-activity inhibitor compounded with a polymer-modified nanomaterial according to any one of the first and second aspects.

[0024] The above technical solutions provided by the present invention have at least the following advantages compared with the prior art:

[0025] The present invention provides an alkali-activity inhibitor compounded with a polymer-modified nanomaterial. Through an orthogonal design method, the present invention optimizes the compatibility of aggregate alkali-activity inhibitors from two ingredient packages and seven components, and formulates an alkali-aggregate activity reaction inhibitor with a super-additive effect of 1 + 1 + 1 > N under an organic-inorganic composite material system. Specifically, it is an alkali-activity inhibitor suitable for the technical characteristics and construction of river pebble concrete, providing key core technical elements and safety guarantees for the rapid construction of river pebble projects, and having wide practical application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The drawings herein are incorporated into the specification and form a part of this specification, showing embodiments consistent with the present invention and used together with the specification to explain the principles of the present invention.

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0028] Figure 1 It is the expansion rate results of the alkali inhibitor in the present invention under different dosages and different curing ages. Figure 1 .

[0029] Figure 2 It is the expansion rate results of the alkali inhibitor in the present invention under different dosages and different curing ages. Figure 2 . DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] To make the objectives, technical solutions, and advantages of the present invention clearer, the following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art without creative efforts based on the embodiments of the present invention belong to the scope of protection of the present invention.

[0031] Unless otherwise specified, all kinds of raw materials, reagents, instruments and equipment used in the present invention can be obtained through market purchase or can be prepared by existing methods.

[0032] In the existing technology, we found that:

[0033] 1. The ingredient contains lithium carbonate. Since the price of lithium carbonate is as high as several hundred thousand yuan per ton (from more than three hundred thousand yuan to more than seven hundred thousand yuan), the price of the aggregate alkali activity inhibitor containing this component is high, and there is an unprecedented cost pressure in the engineering use and promotion.

[0034] 2. The ingredient contains potential toxic substances (such as quaternary ammonium salts). Relevant literature shows that quaternary ammonium salts, also known as quaternary amine salts, are toxic substances. They are not easily biodegradable and inhibit the degradation of other substances, and can continuously accumulate in the natural environment, causing serious water pollution. There may be potential safety hazards endangering health and potential pollution or damage to the water environment during the construction process.

[0035] 3. Many projects also inhibit the alkali-aggregate reaction by adding fly ash and microsilica in combination. However, due to certain regulatory restrictions on the dosage of fly ash and / or silica fume in some high-strength concretes, the inhibition efficiency of the aggregate alkali activity is limited and cannot meet the effectiveness requirements, and other technical means need to be relied on to achieve it.

[0036] Therefore, through the optimization and improvement of the internal system of concrete during the alkali-aggregate reaction process, the present invention achieves permanent prevention of durability damage and impairment of concrete, ensuring the long-term safety and durability of concrete structures. At the same time, combined with the technical characteristics of pebble concrete construction, an aggregate alkali activity inhibitor suitable for the technical characteristics and construction of pebble concrete is formulated, providing key core technical elements and safety guarantees for the rapid construction of pebble projects.

[0037] To solve the above problems, the present invention adopts the following technical solutions:

[0038] In the first aspect, the present invention provides an alkali activity inhibitor compounded with a polymer-modified nanomaterial, and the alkali activity inhibitor includes material A and material B;

[0039] By weight, material A includes the following components:

[0040] 57 - 87 parts of inorganic nano-active material and 0 - 30 parts of mineral admixture;

[0041] By weight, material B includes the following components:

[0042] 0.02 - 0.05 parts of surfactant, 1 - 2 parts of redispersible latex powder, 0.1 - 0.2 parts of hydroxypropyl methyl cellulose ether, 0.1 - 0.2 parts of lignin fiber, and 5 - 10 parts of permeable crystallization component.

[0043] The present invention provides an alkali - activity inhibitor compounded with polymer - modified nanomaterials. Through the method of orthogonal design, the present invention optimizes the compatibility of the aggregate alkali - activity inhibitor from two ingredient packages and seven components, and formulates an alkali - aggregate reactivity inhibitor with a super - superimposed effect of 1 + 1 + 1 > N under the organic - inorganic composite material system. Specifically, it is an alkali - activity inhibitor suitable for the technical characteristics and construction of pebble concrete, providing key core technical elements and safety guarantees for the rapid construction of pebble projects, and having wide practical application value.

[0044] The functions of the components in the alkali - activity inhibitor compounded with polymer - modified nanomaterials provided by the present invention are as follows:

[0045] The inorganic nano - active material is inorganic nano - SiO₂, which belongs to amorphous white powder, non - toxic and odorless, with a spherical shape and a reticular or flocculent microstructure. It has the characteristics of small particle size, large specific surface area, large surface energy, strong adsorption force, and good stability. It exerts its small - size effect, surface effect, quantum - size effect, macroscopic quantum - cavity effect, and ultra - fine particle filling effect at different stages of the whole hydration process of the composite system.

[0046] The mineral admixture is ultra - fine zeolite powder. It is an aluminosilicate mineral with a framework tetrahedral network structure. During the hydration process of the composite system, its alkali metals and alkaline earth metals are loosely combined with water molecules and are easily replaced, endowing it with special adsorption and ion - exchange functions. When the zeolite powder contacts the aqueous solution in the hydration composite system, the metal Na in the solution + enters the zeolite powder, and the Ca in the solution phase 2+ is replaced and enters the hydration products of the composite system to continue participating in the hydration reaction. In addition, due to the electromagnetic field and polar effects inside the zeolite pores, when the hydration reaction is the most intense (2d - 5d) and the hydration heat temperature in the concrete body reaches 70 - 80 degrees Celsius, molecules containing polar groups or polarizable groups can strongly interact with the zeolite surface. And the water in the mixture is a molecule with a very strong polarity. Regardless of the water temperature, water pressure, and linear velocity conditions at this time, it still has a certain adsorption capacity, and both the water absorption rate and the water absorption in the pores are relatively high, forming water - collecting sacs. The water in these water - collecting sacs will be slowly released according to needs during the later hydration reaction, promoting the further continuation of the later hydration.

[0047] Through the extremely high activity of the nano-active material and the water collection effect of the ultra-fine mineral admixture, the alkali in the concrete is adsorbed around it in advance and undergoes a chemical reaction to form a relatively stable precipitate that wraps around the aggregate surface, forming a stable coating layer to isolate and adsorb Na + Temporarily store it in the water collection sac to block the environment for the alkali-aggregate reaction.

[0048] The surfactant is propylene glycol from Dow Chemical of the United States (chemical formula C3H8O2). Utilizing the high dispersibility and stability of the surfactant, the hydration mixing system becomes more uniform during the mixing process, regulating the reaction rate and uniformity of the alkali in the concrete, and making the reaction between the inorganic nano-active material SiO2 and the alkali more sufficient and thorough.

[0049] The redispersible polymer powder is a redispersible polymer powder of vinyl versatate copolymer (chemical formula C 12 H 22 O3).

[0050] (1). The unique alpha-position multi-branched aliphatic structure of the vinyl versatate copolymer protects the polymer chain itself and the adjacent monomer ester bonds from hydrolysis through steric hindrance, thus showing excellent alkali resistance. Especially in a highly alkaline environment, it realizes the water resistance of the persistent redispersible polymer, forming a shield effect.

[0051] (2). Improve the sealing of the mortar system in the concrete;

[0052] (3). By increasing the cohesion of the mortar system in the concrete, improve the tensile strength and crack resistance of the concrete;

[0053] (4). The interwoven polymer regions formed in the concrete also play a role in hindering the merging of microcracks in the mortar system into through-cracks, thereby enhancing the anti-destruction ability and anti-strain ability of the concrete substrate.

[0054] The penetrant crystalline component is composed of five components, namely inorganic sodium carbonate, citric acid, tartaric acid, sodium metasilicate and calcium stearate, through scientific and reasonable optimization of the ratio design.

[0055] In the concrete mortar system, the dissolved silicate ions further diffuse in the concrete with water or moisture, and undergo a secondary chemical reaction with the calcium ions in the concrete to form water-insoluble dendritic calcium silicate crystals. These crystals fill the capillary pores in the concrete and combine with the concrete as a whole, blocking the internal microcracks and capillary channels in the concrete, thereby making the internal structure of the concrete denser and preventing the further penetration and diffusion of water and moisture. In addition, the penetrant crystalline substance has catalytic properties. Once it encounters water, it can continuously wake up the chemical reactions in the system, and the generated crystalline substances continuously repair and heal the internal structure, achieving self-healing and repair within the system.

[0056] In some specific embodiments, the weight ratio of the material A to the material B is (80-90):(10-20).

[0057] In some specific embodiments, the inorganic nano active material is inorganic nano SiO2.

[0058] In some specific embodiments, the mineral admixture is zeolite powder with a particle size of 200-300 mesh.

[0059] In some specific embodiments, the surfactant is propylene glycol.

[0060] In some specific embodiments, the redispersible latex powder is a vinyl versatate copolymer.

[0061] In the present invention, the vinyl versatate copolymer is prepared by copolymerization of vinyl versatate with other monomers such as vinyl acetate, acrylate, etc. Specifically, commercially available products produced by Hebei Siyou Tertiary Carbon New Materials Co., Ltd. can be used, and the product model is SVAE.

[0062] In some specific embodiments, the penetration crystallization component is composed of sodium carbonate, citric acid, tartaric acid, sodium metasilicate and calcium stearate with a weight ratio of (7-8):(1-2):(1-2):(1-2):(0.2-0.3).

[0063] In some specific embodiments, the addition amount of the alkali activity inhibitor of the polymer modified nano material composite provided by the present invention during use is 8%-12% (calculated as the percentage of the weight of cement in the concrete mix). The use method specifically includes the following process: first, add the alkali activity inhibitor to the sand and coarse aggregate and dry mix for 30S, and then sequentially add cement, other admixtures, additives and water for mixing. The mixing time is not less than 2.5 minutes.

[0064] In a second aspect, based on the same inventive concept, the present invention provides a preparation method of the alkali activity inhibitor of the polymer modified nano material composite according to any one of the first aspect. The preparation method includes the following steps:

[0065] Weigh the inorganic nano active material and the mineral admixture in proportion and then mix them to obtain material A;

[0066] Weigh the surfactant, redispersible latex powder, hydroxypropyl methylcellulose ether, lignin fiber and penetration crystallization component in proportion and then mix them to obtain material B.

[0067] The preparation method of the alkali activity inhibitor of the polymer modified nano material composite provided by the present invention has simple operation, does not require additional specific equipment, and is suitable for batch industrial production.

[0068] In a third aspect, based on the same inventive concept, the present invention provides an application of an alkali-activity inhibitor compounded with the polymer-modified nanomaterial according to any one of the first and second aspects in the preparation of concrete.

[0069] In a fourth aspect, based on the same inventive concept, the present invention provides a river pebble concrete, which comprises an alkali-activity inhibitor compounded with the polymer-modified nanomaterial according to any one of the first and second aspects.

[0070] In the present invention, river pebble concrete is a kind of concrete prepared by adding river pebble aggregates during the concrete preparation and formulated according to specific requirements. The river pebble aggregates have good stone shapes and good mechanical properties, so they can increase the compressive strength and durability of the concrete. The river pebble aggregates have diverse particle shapes, which can provide a natural and beautiful stone pattern effect on the concrete surface. River pebble concrete is commonly used in the construction of highway subgrades, bridges, tunnels, docks and other projects. In road engineering, river pebble concrete can be used for the requirements of pavement and subgrade structures, municipal public works, factories, basements and other non-special occasions. Except for the raw materials of the alkali-activity inhibitor compounded with the polymer-modified nanomaterial in the present invention, other component raw materials of the river pebble concrete can be adaptively added according to the prior art and actual use requirements, which will not be elaborated one by one in this invention document.

[0071] It should be noted that for the component raw materials involved in the alkali-activity inhibitor compounded with the polymer-modified nanomaterial and its preparation method provided by the present invention, without special limitation or description, each component can directly adopt commercially available products; for the operation steps involved, without special limitation or description, they can all be carried out according to the operation methods disclosed in the prior art or by using existing equipment according to their usage methods.

[0072] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. For the experimental methods without specific conditions noted in the following embodiments, they are usually determined according to national standards. If there is no corresponding national standard, they are carried out according to general international standards, conventional conditions, or according to the conditions recommended by the manufacturer.

[0073] Example 1

[0074] This example provides an alkali-activity inhibitor compounded with a polymer-modified nanomaterial, and the alkali-activity inhibitor comprises material A and material B with a weight ratio of 90:10;

[0075] Calculated by weight parts, the material A comprises the following components:

[0076] 87 parts of inorganic nano-active material and 13 parts of mineral admixture; wherein, the inorganic nano-active material is inorganic nano-SiO2; the mineral admixture is zeolite powder with a particle size of 200-300 meshes;

[0077] By weight, the B material comprises the following components:

[0078] 0.03 part of surfactant, 1.57 parts of redispersible latex powder, 0.2 part of hydroxypropyl methyl cellulose ether, 0.2 part of lignin fiber and 8 parts of permeable crystallization component; the surfactant is propylene glycol; the redispersible latex powder is a copolymer of vinyl versatate; the permeable crystallization component is composed of sodium carbonate, citric acid, tartaric acid, sodium metasilicate and calcium stearate with a weight ratio of 8:1.5:1.5:1.5:0.25.

[0079] The preparation of the alkali-activity inhibitor compounded with the above polymer-modified nano material comprises the following steps:

[0080] Weigh the inorganic nano-active material and the mineral admixture in proportion and then mix them to obtain the A material;

[0081] Weigh the surfactant, the redispersible latex powder, the hydroxypropyl methyl cellulose ether, the lignin fiber and the permeable crystallization component in proportion and then mix them to obtain the B material.

[0082] Example 2

[0083] This example provides an alkali-activity inhibitor compounded with a polymer-modified nano material. The alkali-activity inhibitor comprises the A material and the B material with a weight ratio of 80:20;

[0084] By weight, the A material comprises the following components:

[0085] 87 parts of inorganic nano-active material and 13 parts of mineral admixture; wherein, the inorganic nano-active material is inorganic nano-SiO2; the mineral admixture is zeolite powder with a particle size of 200-300 meshes;

[0086] By weight, the B material comprises the following components:

[0087] 0.03 part of surfactant, 1.57 parts of redispersible latex powder, 0.2 part of hydroxypropyl methyl cellulose ether, 0.2 part of lignin fiber and 8 parts of permeable crystallization component; the surfactant is propylene glycol; the redispersible latex powder is a copolymer of vinyl versatate; the permeable crystallization component is composed of sodium carbonate, citric acid, tartaric acid, sodium metasilicate and calcium stearate with a weight ratio of 8:1.5:1.5:1.5:0.25.

[0088] The preparation of the alkali-activity inhibitor compounded with the above polymer-modified nano material is the same as that in Example 1.

[0089] Example 3

[0090] This example provides an alkali - activity inhibitor compounded with polymer - modified nanomaterials. The alkali - activity inhibitor includes Material A and Material B with a weight ratio of 70:30.

[0091] By weight, Material A includes the following components:

[0092] 87 parts of inorganic nano - active material and 13 parts of mineral admixture; among them, the inorganic nano - active material is inorganic nano - SiO₂; the mineral admixture is zeolite powder with a particle size of 200 - 300 mesh.

[0093] By weight, Material B includes the following components:

[0094] 0.03 part of surfactant, 1.57 parts of redispersible latex powder, 0.2 part of hydroxypropyl methyl cellulose ether, 0.2 part of lignin fiber, and 8 parts of permeable crystallization component; the surfactant is propylene glycol; the redispersible latex powder is vinyl versatate copolymer; the permeable crystallization component is composed of sodium carbonate, citric acid, tartaric acid, sodium metasilicate, and calcium stearate with a weight ratio of 8:1.5:1.5:1.5:0.25.

[0095] The preparation of the above - mentioned alkali - activity inhibitor compounded with polymer - modified nanomaterials is the same as that in Example 1.

[0096] Comparative Example 1

[0097] This example provides a test of an alkali - activity inhibitor without adding polymer - modified nanomaterials compound. The difference from Example 1 is only that: in the mortar test, there are only cement and sand, and the rest of the steps and parameters are the same.

[0098] Comparative Example 2

[0099] This example provides an alkali - activity inhibitor without adding polymer - modified nanomaterials compound and its preparation method. The difference from Example 1 is only that: in the mortar test, there are cement, fly ash, and sand; the rest of the steps and parameters are the same.

[0100] The above Examples 1 - 3 and Comparative Examples 1 - 2 are tested for alkali - aggregate reactivity in accordance with the standard of GB / T14684 - 2022 "Sand for construction". In the test, the reference cement from Fushun Cement Co., Ltd. is used for cement, and the river sand from Sichuan Langzhong Dinghong Building Materials Co., Ltd. is used for sand.

[0101] Test method: Weigh 440 g of cementitious material and 990 g of sand. The test elements and results of Comparative Examples 1 - 2 and Examples 1 - 3 are shown in Table 1 below:

[0102] Table 1 Test Element Results Table

[0103]

[0104] As can be seen from Table 1:

[0105] In Comparative Example 1, since no alkali inhibitor was added, cracks were found in the specimens at the test ages of 14d, 28d, and 56d. Moreover, as the age increased, the cracks showed an increasing and developing trend, and all the test data exceeded the requirements of the limit values. In Comparative Example 2, although no alkali inhibitor was added, since 30% of the cement was replaced by fly ash in equal amounts, no cracks were found in the specimens at the test ages of 14d, 28d, and 56d. However, the expansion rate at 56d exceeded the limit value, indicating that fly ash also has a certain effect on inhibiting alkali activity. However, with the increase of the age, the inhibiting effect shows a weakening trend, and additional alkali inhibitor still needs to be added to meet the specified requirements.

[0106] In Examples 1 - 3, since 12% of the alkali inhibitor based on the amount of cementitious materials was added, no cracks were found in the specimens at the test ages of 14d, 28d, and 56d. Moreover, under the same age conditions, the changes in the expansion rate were close and there was no obvious change, and the expansion rate at 56d also met the requirement of 0.10, indicating that after adding the alkali inhibitor, the effect of inhibiting the alkali - aggregate reactive effect is obvious. In future continuous experimental studies, we can try long - term observation and experiments to obtain more reliable and safe test data.

[0107] In addition, applying the alkali - activity inhibitor compounded with the polymer - modified nanomaterial provided in Example 1 of this application to river - pebble concrete specifically includes the following process: In addition to the comparative tests under the condition of a fixed dosage of the alkali inhibitor, we conducted comparative experiments on the river - pebble concrete mix proportion under different dosages. The performance tests of the obtained river - pebble concrete are shown in Table 2.

[0108] Table 2 Detection Results Table of the Expansion Rate of Aggregate Alkali Reaction Specimens with Different Dosages of Alkali - Activity Inhibitor

[0109]

[0110] As can be seen from Table 2, when the alkali inhibitor is added, regardless of whether the dosage is 8%, 10%, or 12%, and regardless of whether it is Dinghong sand or Dinghong stone, the expansion rate at the early age (3d) is reduced by about 2 / 3 compared with that without adding the alkali inhibitor, the expansion rate at the 7d age is reduced by about 4 / 5, the expansion rate at the 14d age is reduced by about 4 / 5, and the expansion rate at the 28d age is reduced by 50% - 70%. This further confirms that after adding the alkali inhibitor, the reduction amplitude of the expansion rate is extremely significant and the inhibiting effect is very effective, as shown in Figure 1 and Figure 2 shown. Moreover, from Figure 1 andFigure 2 It can be seen that with the increase of the dosage of alkali inhibitor, the expansion rate at each age shows a trend of change similar to a function curve.

[0111] To further expand the application scope of alkali-activity inhibitors, we also carried out verification tests on the expansion effect under different combinations of fly ash dosages and alkali inhibitor dosages using river pebbles Dinghong sand. The test results are shown in Table 3. It can be seen from Table 3 that Test No. 1# is the case without fly ash and without alkali inhibitor, and its expansion rates at 7d, 14d, and 28d all exceed the specified 0.1%, and the expansion rate at 28d exceeds the limit value by about 5 times.

[0112] For the three groups of Test Nos. 2#, 3#, and 4#, the fly ash dosage is 5%. When the alkali inhibitor dosage is 8%, 10%, and 12%, their expansion rates at 7d, 14d, and 28d are all between 0.03% and 0.09%, and do not exceed the limit value of 0.1%.

[0113] For the three groups of Test Nos. 5#, 6#, and 7#, the fly ash dosage is 10%. When the alkali inhibitor dosage is 8%, 10%, and 12%, their expansion rates at 7d, 14d, and 28d are all between 0.02% and 0.09%, and do not exceed the limit value of 0.1%. Moreover, with the increase of the inhibitor dosage, the expansion rate decreases, and when the alkali inhibitor dosage is 10%, it has reached 0.05%.

[0114] For the three groups of Test Nos. 8#, 9#, and 10#, the fly ash dosage is 15%. When the alkali inhibitor dosage is 8%, 10%, and 12%, their expansion rates at 7d, 14d, and 28d are all between 0.02% and 0.06%, and do not exceed the limit value of 0.1%. With the change of the alkali inhibitor dosage, the expansion rate at 28 days is between 0.05% and 0.06%, and the change of the expansion rate with the alkali inhibitor dosage is not very sensitive. The lowest dosage of alkali inhibitor can be selected as the screening result.

[0115] For the four groups of Test Nos. 11#, 12#, 13#, and 14#, the fly ash dosage is 20%. When the alkali inhibitor dosage is 6%, 7%, 8%, and 10%, their expansion rates at 7d, 14d, and 28d are all between 0.02% and 0.05%, and do not exceed the limit value of 0.1%. It shows that when the fly ash dosage is 20%, the effect of compounding with alkali inhibitor is more ideal.

[0116] For the three groups of Test Nos. 15#, 16#, and 17#, the fly ash dosage is 25%. When the alkali inhibitor dosage is 4%, 6%, and 8%, their expansion rates at 7d, 14d, and 28d are all between 0.01% and 0.04%, and do not exceed the limit value of 0.1%. It shows that when the maximum allowable fly ash dosage is reached, adding a small amount of alkali inhibitor can meet the requirement of the expansion rate limit value.

[0117] For the three groups with test numbers 18#, 19#, and 20#, the fly ash content is 30%. When the alkali inhibitor content is 4%, 6%, and 8%, the expansion rates at 7d, 14d, and 28d are all between 0.00% and 0.03%, without exceeding the limit value of 0.1%.

[0118] Generally speaking, when the alkali inhibitor is used in combination with fly ash, at the contents of 4%, 6%, 7%, 8%, 10%, and 12%, the expansion rate shows a decreasing trend, and with the increase of the fly ash content, the alkali inhibition effect under the combined use is more obvious. In engineering practice, when the maximum fly ash content is allowed, the content of the alkali inhibitor can be appropriately reduced to obtain better technical and economic benefits.

[0119] Table 3 Expansion rates at different ages under different fly ash contents and different alkali inhibitor contents

[0120]

[0121]

[0122] In summary, the embodiments of the present invention and more extensive expansion tests provide an alkali - activity inhibitor composite with polymer - modified nanomaterials, its preparation method and application. Through the orthogonal design method, the present invention optimizes the compatibility of the aggregate alkali - activity inhibitor from two ingredient packages and seven components, and formulates an alkali - aggregate reactivity inhibitor with a super - superimposed effect of 1 + 1 + 1 > N under the organic - inorganic composite material system, specifically an alkali - activity inhibitor suitable for the technical characteristics and construction of pebble concrete, providing key core technical elements and safety guarantees for the rapid construction of pebble projects, and having wide practical application value.

[0123] The various embodiments of the present invention may exist in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be construed as a rigid limitation on the scope of the present invention; therefore, it should be considered that the range description has specifically disclosed all possible sub - ranges and single values within that range. For example, the test results of the comparative examples and embodiments. Additionally, whenever a numerical range is indicated herein, it means including any cited number (fraction or integer) within the indicated range.

[0124] The above are only specific embodiments of the present invention, enabling those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein may be manifested in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but will conform to the broadest scope consistent with the principles and novel features claimed herein.

Claims

1. Application of an alkali-activity inhibitor compounded with a polymer-modified nanomaterial in reducing the expansion rate of river pebble concrete aggregates, characterized in that, The alkali activity inhibitor includes Material A and Material B; By weight, Material A includes the following components: 57 - 87 parts of inorganic nano - active material and 13 - 30 parts of mineral admixture; the inorganic nano - active material is inorganic nano - SiO2, and the mineral admixture is zeolite powder with a particle size of 200 - 300 mesh; By weight, Material B includes the following components: 0.02 - 0.05 part of surfactant, 1 - 2 parts of redispersible latex powder, 0.1 - 0.2 part of hydroxypropyl methyl cellulose ether, 0.1 - 0.2 part of lignin fiber, and 5 - 10 parts of permeable crystallization component; the surfactant is propylene glycol, the redispersible latex powder is vinyl versatate copolymer, and the permeable crystallization component is composed of sodium carbonate, citric acid, tartaric acid, sodium metasilicate, and calcium stearate with a weight ratio of (7 - 8):(1 - 2):(1 - 2):(1 - 2):(0.2 - 0.3); The preparation method of the alkali activity inhibitor compounded with polymer - modified nano - materials includes the following steps: Weigh the inorganic nano - active material and the mineral admixture in proportion and then mix them to obtain Material A; Weigh the surfactant, redispersible latex powder, hydroxypropyl methyl cellulose ether, lignin fiber, and permeable crystallization component in proportion and then mix them to obtain Material B.

2. Use of the alkali-activity inhibitor compounded with the polymer-modified nanomaterial according to claim 1 in reducing the expansion rate of river pebble concrete aggregate, characterized in that, The weight ratio of Material A to Material B is (80 - 90):(10 - 20).

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