Mica modifier, its use and concrete and method for producing same

Abstract

The application relates to the technical field of building materials, and particularly discloses a mica modifier, application of the mica modifier and concrete and a preparation method of the concrete, wherein the mica modifier comprises the following components: a polyoxyethylene surfactant, polyethylene glycol and sodium dodecyl sulfate. The concrete comprises the following components in parts by weight: 290-330 kg / m of low-heat portland cement 3 , 738-765 kg / m of fine sand, 1200-1350 kg / m of 5-20 mm aggregate 3 , 55-85 kg / m of water 3 and 2-4 kg / m of the mica modifier 3 . The mica modifier can be directly added into building materials containing mica to modify the mica, improve the interface bonding force between the fine aggregate mica and cement stone, and improve the mechanical properties and frost resistance of the concrete prepared by adding the mica modifier, that is, the application can solve the complicated process of removing mica sheets by manual cleaning and magnetic separation in the current engineering, and the adverse effects of the mica on the concrete can be solved by directly adding the modified material in the concrete.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of building materials, in particular to a mica modifier and application thereof and concrete and a preparation method thereof. BACKGROUND

[0002] At present, large and medium-sized hydropower projects in China are mainly concentrated in the western region, and the largest building material used in the construction of hydropower projects is building material. Due to the lack of sufficient natural sand resources, many projects use the method of mechanically crushing rocks to produce artificial sand. Mica is one of the common rock-forming minerals, and the mica content in the parent rock of some engineering concrete aggregate is relatively high. For example, the mica content in the granite used as the coarse aggregate source for the concrete of the Three Gorges Project is as high as 10%. The mica content in the artificial sand produced by rolling the parent rock with high mica content is also high. Therefore, the current national standard and many industry standards limit the mica content in the sand. DL / T 5144-2015 "Concrete Construction Specification for Hydraulic Engineering" regulates the quality of fine aggregate, and requires that the mica content in natural sand and artificial sand should be ≤2%. This is mainly because mica is generally in the form of flake, has a smooth surface, is absolutely inert, and is easy to crack along the joint, and has poor adhesion with cement paste, which increases the internal strength defects of concrete. The surface of mica is relatively hydrophilic, and a water film is easily formed on the surface under normal temperature and humidity. When the mica content in fine aggregate exceeds a certain limit, the workability, mechanical properties and durability of the concrete mixture are significantly reduced.

[0003] At present, in the preparation process of building materials, the mica content in fine aggregate is mainly controlled to reduce the adverse effects of mica on concrete. The main way to reduce mica is to remove mica flakes by artificial cleaning and magnetic separation, which is complicated and time-consuming. There is no research on the combination of mica in fine aggregate and the interface of cement stone to propose a technology for modifying the building mica. SUMMARY

[0004] The purpose of the present application is to provide a mica modifier and application thereof. The mica modifier can be directly added to building materials containing mica. The modification of mica can reduce the thickness of the water film on the surface of mica in fine aggregate or replace the surface of mica with the modifier, and the modifier is arranged on the interface between the two phases to make the surface have a low-density charge, significantly reduce the surface tension or interface tension, and improve the bonding force between fine aggregate mica and cement stone interface.

[0005] In addition, the present application also provides concrete comprising the above-mentioned mica modifier and a preparation method thereof.

[0006] The present application is realized by the following technical solutions:

[0007] A mica modifier comprises the following components:

[0008] Polyoxyethylene surfactant, polyethylene glycol and sodium dodecyl sulfate.

[0009] The mica modifier is designed to:

[0010] First, improve the problem of too thick water film on the surface of fine aggregate mica, reduce the interfacial tension between mica and cement stone; second, improve the problem of fine aggregate mica and cement stone interface bonding; third, solve the cumbersome process of manual removal and magnetic separation of mica sheets in current engineering, and directly add modified materials in concrete to solve the adverse effects of mica on concrete.

[0011] The mica modifier is a composition of polyoxyethylene surfactant, polyethylene glycol and sodium dodecyl sulfate, which can improve the water film thickness on the surface of fine aggregate mica or replace the mica surface with the modifier to improve the performance of concrete. The principle of action: the molecular characteristics of polyoxyethylene surfactant, polyol surfactant and sodium dodecyl sulfate surfactant are chemical substances with hydrophilic groups (segments) at one end and hydrophobic groups (segments) at the other end, i.e. a class of chemical substances with hydrophilic and hydrophobic properties. When the above-mentioned polyoxyethylene surfactant, polyethylene glycol and sodium dodecyl sulfate are added to the concrete, the modifier is adsorbed on the surface of the mica in a layered film structure, which reduces the water film thickness on the surface of the mica or is replaced by the modifier, and the modifier is arranged on the interface between the two phases, so that the surface has a low density charge, significantly reducing the surface tension or interfacial tension, and improving the interfacial bonding capacity of mica and cement stone.

[0012] In summary, the mica modifier can be directly added to the building materials containing mica to modify the mica, improve the water film thickness on the surface of fine aggregate mica, and improve the interfacial bonding force of fine aggregate mica and cement stone.

[0013] Further, the following weight percentage components are included:

[0014] Polyethylene glycol 15-25%, sodium dodecyl sulfate 15-25%, and the balance is polyoxyethylene surfactant.

[0015] Further, the following weight percentage components are included:

[0016] Polyethylene glycol 20%, sodium dodecyl sulfate 20%, and polyoxyethylene surfactant 60%.

[0017] Further, the polyoxyethylene surfactant is alkyl phenol polyoxyethylene ether (OP-10).

[0018] Application of mica modifier in preparation of mica-containing building materials.

[0019] Further, the building material includes concrete and aggregate.

[0020] A concrete, wherein a mica modifier is added.

[0021] Further, the concrete includes the following components:

[0022] Low-heat Portland cement, fine sand, aggregate, water and mica modifier.

[0023] Further, the concrete includes the following components by weight:

[0024] Low-heat Portland cement 290-330 kg / m 3 , fine sand 738-765, 5-20 mm aggregate 1200-1350 kg / m 3 , water 55-85 kg / m 3 and mica modifier 2-4 kg / m 3 .

[0025] A method for preparing a concrete, comprising the following steps:

[0026] S1, material preparation: the low-heat Portland cement, fine sand, aggregate and mica modifier are weighed according to the formula, fully stirred and uniformly mixed, and reserved;

[0027] S2, mixing and preparation of concrete: half of the formula amount of water is first added to the above mixture and stirred for 2-3 min, and then the remaining water is gradually added and fully stirred for 3-5 min;

[0028] S3, concrete construction: the prepared concrete is mixed and constructed according to the design requirements, and water is added regularly for maintenance.

[0029] Compared with the prior art, the present application has the following advantages and beneficial effects:

[0030] 1. The mica modifier of the present application can be directly added to the building material containing mica. The modifier composed of polyoxyethylene surfactant, polyethylene glycol and sodium dodecyl sulfate is adsorbed on the surface of mica in a layered film structure, which reduces the thickness of the water film on the surface of mica or covers it with the modifier, and at the same time, the modifier is arranged on the interface between two phases, so that the surface has a low-density charge, significantly reducing the surface tension or interfacial tension, improving the interface bonding capacity of mica and cement stone, and the mechanical properties and frost resistance of the concrete prepared by adding the mica modifier are also improved.

[0031] 2. When the mica modifier is added to the building material containing mica to modify the mica, the mica modifier can reduce the content of mica in the fine aggregate without removing the mica in the fine aggregate by manual operation or magnetic separation, thereby reducing the cumbersome operation and improving the construction efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0032] The drawings described herein are used to provide further understanding of the embodiments of the present application, form a part of the present application, and do not constitute a limitation on the embodiments of the present application. In the drawings:

[0033] Figure 1 is an electron microscope image of the interface between mica and cement stone when no mica modifier is added;

[0034] Figure 2 is an electron microscope image of the interface between mica and cement stone when the mica modifier is added. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical scheme and advantages of the present application more clear and obvious, the present application will be further described in detail below in combination with embodiments and drawings, the illustrative embodiments of the present application and the description thereof are used to explain the present application, and do not constitute a limitation on the present application.

[0036] Embodiment 1:

[0037] A mica modifier, consisting of the following components by weight percentage:

[0038] Polyethylene glycol 20%, sodium dodecyl sulfate 20%, polyoxyethylene surfactant 60%, wherein the polyoxyethylene surfactant is alkyl phenol polyoxyethylene ether (OP-10).

[0039] The mica modifier described in this embodiment can be directly added to the building material containing mica. The modifier composed of polyoxyethylene surfactant, polyethylene glycol and sodium dodecyl sulfate is adsorbed on the surface of mica in the form of a layered film structure, which reduces the thickness of the water film on the surface of mica or replaces it with the modifier, and at the same time, the modifier is arranged on the interface between the two phases, so that the surface has a low density charge, significantly reducing the surface tension or interfacial tension, improving the interface bonding capacity of mica and cement stone, and the mechanical properties and frost resistance of the concrete prepared by adding the mica modifier are also improved.

[0040] That is, the mica modifier described in this embodiment can be used to prepare mica-containing building materials, and the building materials include concrete and aggregate, that is, the mica modifier can be added to the concrete containing aggregate to modify the mica in the aggregate, or it can be directly added to the aggregate to directly modify the mica in the aggregate.

[0041] Embodiment 2:

[0042] A kind of concrete, comprising the following weight parts components:

[0043] Low-heat Portland cement 300 kg / m 3 , fine sand 745 kg / m 3 , 5-20 mm aggregate 1280 kg / m 3 , water 58 kg / m 3 And mica modifier 2 kg / m 3 .

[0044] 5-20 mm aggregate refers to the aggregate is fine aggregate, the particle size of fine aggregate is 5-20 mm, and the mica content in the aggregate is 10%.

[0045] In this embodiment, the mica modifier is prepared by the mica modifier of example 1.

[0046] The preparation method of the concrete described in this embodiment comprises the following steps:

[0047] S1, material preparation: weigh low-heat Portland cement, fine sand, aggregate and mica modifier according to the formula, mix thoroughly and uniformly, and reserve;

[0048] S2, mixing and preparation of concrete: first add half of the formula amount of water to the above mixture and stir, stir for 2 min, then add the remaining water and stir thoroughly, stir for 3 min;

[0049] S3, concrete construction: mix the prepared concrete to make concrete test blocks, which are recorded as sample 1, for performance testing.

[0050] The electron microscope image of the interface between mica and cement stone in sample 1 is shown in Figure 2 .

[0051] Example 3:

[0052] A kind of concrete, comprising the following weight parts components:

[0053] Low-heat Portland cement 310 kg / m 3 , fine sand 750 kg / m 3 , 5-20 mm aggregate 1300 kg / m 3 , water 58 kg / m 3 And mica modifier 3 kg / m 3 .

[0054] 5-20 mm aggregate refers to the aggregate is fine aggregate, the particle size of fine aggregate is 5-20 mm, and the mica content in the aggregate is 10%.

[0055] In this embodiment, the mica modifier is prepared by the mica modifier of example 1.

[0056] The difference between the concrete described in the embodiment and the concrete described in embodiment 2 is that the doping amount of the mica modifier is different.

[0057] The preparation method of the concrete described in the embodiment includes the following steps:

[0058] S1, material preparation: the low-heat Portland cement, fine sand, aggregate and mica modifier are weighed according to the formula, fully stirred and uniformly prepared;

[0059] S2, mixing and preparation of concrete: half of the formula amount of water is first added to the above mixture for stirring, and then the remaining water is gradually added for fully stirring, and the stirring time is 3 min;

[0060] S3, concrete construction: the mixed and prepared concrete is made into a concrete test block, which is recorded as sample 2, and is used for performance test.

[0061] Comparative example 1:

[0062] A mica modifier is composed of the following components by weight percentage:

[0063] Polyethylene glycol 30%, sodium dodecyl sulfate 30%, polyoxyethylene surfactant 40%, wherein the polyoxyethylene surfactant is alkyl phenol polyoxyethylene ether (OP-10).

[0064] Comparative example 2:

[0065] A concrete includes the following components by weight:

[0066] Low-heat Portland cement 300 kg / m 3 , fine sand 745 kg / m 3 , 5-20 mm aggregate 1280 kg / m 3 , water 58 kg / m 3 and mica modifier 2 kg / m 3 .

[0067] The 5-20 mm aggregate refers to fine aggregate, the particle size of the fine aggregate is 5-20 mm, and the mica content in the aggregate is 10%.

[0068] In the present comparative example, the mica modifier prepared in comparative example 1 is used.

[0069] The preparation method of the concrete described in the embodiment includes the following steps:

[0070] S1, material preparation: the low-heat Portland cement, fine sand, aggregate and mica modifier are weighed according to the formula, fully stirred and uniformly prepared;

[0071] S2, mixing and preparation of concrete: half of the formula amount of water is first added to the above mixture for stirring, stirring for 2 min, and then the remaining water is added for sufficient stirring, stirring for 3 min;

[0072] S3, concrete construction: the mixed and prepared concrete is made into a concrete test block, denoted as sample 3, for performance testing.

[0073] Comparative Example 3:

[0074] A mica modifier consists of the following components by weight percentage:

[0075] Sodium dodecyl sulfate 30%, polyoxyethylene surfactant 70%, wherein the polyoxyethylene surfactant is alkyl phenol polyoxyethylene ether (OP-10).

[0076] Comparative Example 4:

[0077] A concrete includes the following components by weight:

[0078] Low-heat Portland cement 300 kg / m 3 , fine sand 745 kg / m 3 , 5-20 mm aggregate 1280 kg / m 3 , water 58 kg / m 3 and mica modifier 2 kg / m 3 .

[0079] The 5-20 mm aggregate refers to fine aggregate, the particle size of the fine aggregate is 5-20 mm, and the mica content in the aggregate is 10%.

[0080] In this comparative example, the mica modifier is the mica modifier prepared in Comparative Example 3.

[0081] The preparation method of the concrete described in this example includes the following steps:

[0082] S1, material preparation: the low-heat Portland cement, fine sand, aggregate and mica modifier are weighed according to the formula, fully stirred and uniformly prepared for use;

[0083] S2, mixing and preparation of concrete: half of the formula amount of water is first added to the above mixture for stirring, stirring for 2 min, and then the remaining water is added for sufficient stirring, stirring for 3 min;

[0084] S3, concrete construction: the mixed and prepared concrete is made into a concrete test block, denoted as sample 4, for performance testing.

[0085] Comparative Example 5:

[0086] A mica modifier consists of the following components by weight percentage:

[0087] Polyethylene glycol 40%, polyoxyethylene surfactant 60%, wherein; the polyoxyethylene surfactant is alkylphenol polyoxyethylene ether (OP-10).

[0088] Comparative Example 6:

[0089] A concrete comprising the following components by weight:

[0090] Low-heat Portland cement 300 kg / m 3 , fine sand 745 kg / m 3 , 5-20 mm aggregate 1280 kg / m 3 , water 58 kg / m 3 and mica modifier 2 kg / m 3 .

[0091] 5-20 mm aggregate refers to fine aggregate, the particle size of fine aggregate is 5-20 mm, and the content of mica in the aggregate is 10%.

[0092] In the present comparative example, the mica modifier is the mica modifier prepared in Comparative Example 5.

[0093] The preparation method of the concrete described in the present example comprises the following steps:

[0094] S1, material preparation: weigh the low-heat Portland cement, fine sand, aggregate and mica modifier according to the formula, fully stir and mix uniformly, and reserve;

[0095] S2, mixing and preparation of concrete: first add half of the formula amount of water to the above mixture and stir, stir for 2 min, then successively add the remaining water and fully stir, stir for 3 min;

[0096] S3, concrete construction: the mixed and prepared concrete is made into a concrete test block, which is recorded as sample 5, and is used for performance test.

[0097] Comparative Example 7:

[0098] A concrete comprising the following components by weight:

[0099] Low-heat Portland cement 300 kg / m 3 , fine sand 745 kg / m 3 , 5-20 mm aggregate 1280 kg / m 3 , water 58 kg / m 3 .

[0100] 5-20 mm aggregate refers to fine aggregate, the particle size of fine aggregate is 5-20 mm, and the content of mica in the aggregate is 10%.

[0101] That is, the present comparative example is based on Example 2, and differs from Example 2 in that the concrete is prepared without adding the mica modifier prepared in Example 1.

[0102] The method for preparing the concrete of the present example comprises the following steps:

[0103] S1, material preparation: the low-heat portland cement, fine sand and aggregate are weighed according to the formula, fully stirred and uniformly mixed, and reserved;

[0104] S2, mixing and preparation of the concrete: half of the water according to the formula is first added to the above mixture and stirred for 2 min, and then the remaining water is added and fully stirred for 3 min;

[0105] S3, construction of the concrete: the mixed and prepared concrete is made into a concrete test block, which is denoted as sample 6, for performance testing.

[0106] The electron microscope image of the interface between the mica and the cement stone in sample 7 is shown in Figure 1 .

[0107] The compressive, flexural and frost resistance properties of the concrete test blocks (samples 1-6) are tested, and the results are shown in Table 1:

[0108] Table 1

[0109]

[0110] From the data in Table 1, in combination with Figures 1-2 comparisons, it can be seen that:

[0111] 1) Mechanical properties: when the mica content in the fine aggregate is 10%, the 28d compressive strength of the concrete test piece with the added mica modifier can reach 62.5 MPa, and the 28d compressive strength of the test piece without the added mica modifier reaches 48.8 MPa.

[0112] 2) Frost resistance: when the mica content in the fine aggregate is 10%, the concrete test piece with the added mica modifier has a frost resistance grade of F300, and the strength and quality of the concrete member do not decrease and the quality does not lose after 300 times of freeze-thaw cycles. The frost resistance grade of the concrete test piece without the added mica modifier is F200.

[0113] 3) Interfacial bonding properties: by observing the interfacial bonding state of the mica and the cement stone with and without the added mica modifier through a scanning electron microscope, it can be found that the addition of the modifier can significantly improve the interfacial bonding ability.

[0114] To sum up, the present application can change the current means of removing mica in hydropower engineering by adding mica modifier to the concrete, that is, the modifier is adsorbed on the surface of mica in the form of layered film, so that the water film thickness on the surface of mica is reduced or replaced and covered by the modifier, and the modifier is arranged on the interface between the two phases, so that the surface has low-density charge, the surface tension or interfacial tension is significantly reduced, the interface bonding capacity of mica and cement stone is improved, the adverse effects of mica are solved, and the performance of concrete is not affected under the condition of high mica content.

[0115] The present application can solve the problem of high mica content in fine aggregate in hydropower engineering and railway engineering, has great practical significance in engineering, and can save engineering cost.

[0116] The above specific embodiments further illustrate the purpose, technical solutions and beneficial effects of the present application, and it should be understood that the above description is only a specific embodiment of the present application and is not used to limit the protection scope of the present application, and any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A mica modifier characterized in that, Comprise the following components: Polyoxyethylene surfactant, polyethylene glycol and sodium dodecyl sulfate, each component weight percentage: polyethylene glycol 15-25%, sodium dodecyl sulfate 15-25%, the balance is polyoxyethylene surfactant; The polyoxyethylene surfactant is alkylphenol polyoxyethylene ether.

2. The mica modifier of claim 1, wherein, Comprise the following components by weight percentage: Polyethylene glycol 20%, sodium dodecyl sulfate 20%, polyoxyethylene surfactant 60%.

3. Use of the mica modifier according to any one of claims 1-2 in the preparation of mica-containing building materials.

4. Use according to claim 3, characterized in that, The building materials include concrete and aggregate.

5. Concrete, characterized in that The mica modifier according to any one of claims 1-2 is added to the concrete.

6. A concrete according to claim 5, characterised in that Comprise the following components: Low-heat Portland cement, fine sand, aggregate, water and mica modifier.

7. A concrete according to claim 5, characterised in that Comprise the following components by weight: Low heat Portland cement 290-330 kg / m 3 Fine sand 738-765, 5-20 mm aggregate 1200-1350 kg / m 3 Water 55-85 kg / m 3 And mica modifier 2-4 kg / m 3 .

8. The method for preparing concrete as described in claim 6, characterized in that, Comprise the following steps: S1, preparation: according to the formula, low-heat Portland cement, fine sand, aggregate and mica modifier are weighed, fully stirred and uniformly prepared for use; S2, mixing and preparation of concrete: in the above mixture, half of the formula amount of water is first added for stirring, stirring for 2-3 min, then the remaining water is gradually added for fully stirring, stirring for 3-5 min; S3, concrete construction: the mixed and prepared concrete is used for concrete construction according to the design requirements, and water is added for maintenance regularly.

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