Environment-friendly high-performance concrete and preparation process thereof

Abstract

The present application relates to the technical field of building materials, in particular to an environment-friendly high-performance concrete and a preparation process thereof. The environment-friendly high-performance concrete is prepared by using Portland cement, fine aggregate, coarse aggregate, defoaming agent, fly ash, water, polycarboxylic acid water reducing agent, water-absorbing resin and diatomite. The materials used in the concrete are environment-friendly, and the prepared concrete has good crack resistance and permeability resistance, meeting the industrial application. The present application provides a preparation method of environment-friendly water-absorbing resin. The water-absorbing resin is prepared by using natural high-molecular carbohydrate potato starch containing a large number of hydroxyl groups, natural compound bentonite with large specific surface area and acrylic acid as raw materials. The addition of the water-absorbing resin in the concrete can increase the capillary pore structure in the concrete and improve the crack resistance of the concrete.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of building materials, in particular to an environment-friendly high-performance concrete and a preparation process thereof. BACKGROUND

[0002] The concrete is a kind of building material formed by configuring gel material, water, fly ash, cement and aggregate in proper proportion and then hardening. The concrete has high hardness, good durability, simple production process, wide raw material sources and wide application range, and can be applied to house and highway construction.

[0003] In order to protect the environment and save resources, the environment-friendly water-absorbing resin prepared from starch is often used as an additive in the field of concrete. However, the concrete prepared by adding the water-absorbing resin still has many problems to be improved, such as poor crack resistance and poor impermeability.

[0004] In order to solve the above problems and improve the crack resistance and impermeability of the concrete, the present application provides an environment-friendly high-performance concrete and a preparation process thereof. SUMMARY

[0005] The present application aims to provide an environment-friendly high-performance concrete and a preparation process thereof to solve the problems in the background art.

[0006] In order to solve the above technical problems, the present application provides the following technical scheme:

[0007] A preparation process of an environment-friendly high-performance concrete, comprising the following steps:

[0008] Step 1: Take acrylic acid, add sodium hydroxide aqueous solution, adjust the pH value to 6-7, add potato starch, modified bentonite, potassium persulfate solution and N-N methylene bisacrylamide solution, stir uniformly, heat to 40-45 DEG C, stir, then heat to 70-75 DEG C, continue to stir, granulate, dry, crush, and obtain a water-absorbing resin;

[0009] Step 2: Stir the portland cement, fine aggregate, coarse aggregate and defoaming agent uniformly, add fly ash, water and polycarboxylic acid water reducer, stir for 20-25 min, add the water-absorbing resin and diatomite, stir for 25-30 min, and obtain an environment-friendly high-performance concrete.

[0010] More preferably, the environment-friendly high-performance concrete comprises the following ingredients by weight: 400-480 parts of portland cement, 470-500 parts of fine aggregate, 840-900 parts of coarse aggregate, 2-3 parts of defoaming agent, 70-80 parts of fly ash, 170-220 parts of water, 11-14 parts of polycarboxylic acid water reducer, 18-20 parts of water-absorbing resin and 30-35 parts of diatomite.

[0011] More preferably, the defoaming agent is any one of polypropylene glycol or polyethylene glycol.

[0012] More preferably, the particle size of the diatomite is 650-700 mesh.

[0013] More preferably, the preparation method of the modified bentonite comprises the following steps:

[0014] S1: take bentonite and deionized water, stir uniformly, add cetyltrimethylammonium bromide solution, stir uniformly, heat to 50-55 DEG C, react for 2-3 h, wash, dry, and obtain pretreated bentonite;

[0015] S2: take the calcium nitrite coated with chitosan, deionized water, stir uniformly, add the pretreated bentonite, stir for 14-16 h, and obtain the modified bentonite.

[0016] More preferably, the particle size of the bentonite is 250-300 mesh.

[0017] More preferably, the mass ratio of the calcium nitrite coated with chitosan and the pretreated bentonite is 2: (5-6).

[0018] More preferably, the preparation method of the calcium nitrite coated with chitosan is: take chitosan and acetic acid solution, stir uniformly, and obtain chitosan solution; take calcium nitrite and deionized water, stir uniformly, and obtain calcium nitrite solution; take triphenyl phosphate and deionized water, stir uniformly, and obtain triphenyl phosphate solution; add the calcium nitrite solution to the chitosan solution, stir uniformly, add the triphenyl phosphate solution, stir for 40-50 min, stand, take the supernatant, centrifuge, wash, dry, and obtain the calcium nitrite coated with chitosan.

[0019] Compared with the prior art, the present application has the following beneficial effects:

[0020] (1) The present application uses portland cement, fine aggregate, coarse aggregate, defoaming agent, fly ash, water, polycarboxylic acid water reducer, water absorbing resin, diatomite to prepare an environment-friendly high-performance concrete. The materials used in the concrete are environmentally friendly, and the prepared concrete has good crack resistance and impermeability, excellent performance, and meets the industrial application.

[0021] (2) The present application provides a preparation method of water absorbing resin. The water absorbing resin is prepared from natural high molecular carbohydrate potato starch containing a large amount of hydroxyl groups, natural compound bentonite with large specific surface area, and acrylic acid as raw materials. The addition of the water absorbing resin in the concrete can increase the capillary pore structure inside the concrete and improve the crack resistance of the concrete.

[0022] (3) The application firstly uses a cetyltrimethylammonium bromide solution to pretreat bentonite, and the addition of the cetyltrimethylammonium bromide can increase the porosity of the bentonite. The application also provides a preparation method of the calcium nitrite coated with chitosan, the calcium nitrite is coated with chitosan, and is loaded on the pretreated bentonite; a large number of amino groups on the chitosan can react with amino groups and carboxyl groups on the water-absorbing resin, so that the dispersibility of the bentonite in the water-absorbing resin is improved; the loading of the calcium nitrite can change the pore structure of the concrete, increase the porosity, and improve the impermeability of the concrete. Meanwhile, the mass ratio of the calcium nitrite coated with chitosan to the pretreated bentonite is controlled to be 2: (5-6), and the impermeability is optimal at this time. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the application will be clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the application.

[0024] The sources or models of some raw materials in the application are as follows:

[0025] The silicate cement is P.O32.5;

[0026] The particle size of the bentonite is 250-300 mesh;

[0027] The particle size of the diatomite is 650-700 mesh;

[0028] The potato starch is provided by Inner Mongolia Minfeng Potato Industry Co., Ltd.;

[0029] Acrylic acid: item number 79-10-7, provided by Jinan Mingwei Chemical Co., Ltd.

[0030] Embodiment 1: A preparation process of an environment-friendly high-performance concrete, comprising the following steps:

[0031] Step one: preparation of calcium nitrite coated with chitosan:

[0032] Take 0.2 g of chitosan, 50 mL of 1% acetic acid solution, and stir uniformly to obtain a chitosan solution; take 0.2 g of calcium nitrite, 50 mL of deionized water, and stir uniformly to obtain a calcium nitrite solution; take 2 mg of triphenyl phosphate, 20 mL of deionized water, and stir uniformly to obtain a triphenyl phosphate solution; add the calcium nitrite solution to the chitosan solution, stir uniformly, add the triphenyl phosphate solution, stir for 45 min, stand, take the supernatant, centrifuge, wash, and dry to obtain calcium nitrite coated with chitosan;

[0033] Step two: preparation of modified bentonite:

[0034] Take 5g bentonite, 40mL deionized water, stir evenly, add 60mL concentration of 2.5% cetyl trimethyl ammonium bromide solution, stir evenly, heat to 53℃, react for 2.5h, wash, dry, get pretreated bentonite;

[0035] Take 2g coated calcium nitrite with chitosan, 50mL deionized water, stir evenly, add 5.5g pretreated bentonite, stir for 15h, get modified bentonite.

[0036] The mass ratio of coated calcium nitrite with chitosan and pretreated bentonite is 2:5.5.

[0037] Step three: preparation of water absorbing resin:

[0038] Take 100g acrylic acid, add 40% sodium hydroxide aqueous solution, adjust pH value to 6.5, add 5g potato starch, 5g modified bentonite, 0.01g concentration of 1% potassium persulfate solution, 0.01g concentration of 1% N-N methylene double acrylamide solution, stir evenly, heat to 43℃, stir for 2.5h, then heat to 73℃, stir for 60min, granulation, drying, crushing, get water absorbing resin;

[0039] Step four: preparation of environment-friendly high-performance concrete:

[0040] Mix silicate cement, fine aggregate, coarse aggregate, polyethylene glycol defoaming agent, add fly ash, water, polycarboxylic acid water reducer, stir for 23min, add water absorbing resin, diatomite, stir for 28min, get an environment-friendly high-performance concrete;

[0041] The environment-friendly high-performance concrete, by weight, includes the following ingredients:

[0042] 460 parts of silicate cement, 480 parts of fine aggregate, 880 parts of coarse aggregate, 2.5 parts of polyethylene glycol defoaming agent, 75 parts of fly ash, 200 parts of water, 13 parts of polycarboxylic acid water reducer, 19 parts of water absorbing resin, 32 parts of diatomite.

[0043] Example 2: preparation process of an environment-friendly high-performance concrete, including the following steps:

[0044] Step one: preparation of coated calcium nitrite with chitosan:

[0045] Take 0.2g chitosan, 50mL concentration of 1% acetic acid solution, stirring, get chitosan solution; take 0.2g calcium nitrite, 50mL deionized water, stirring, get calcium nitrite solution; take 2mg triphenyl phosphate, 20mL deionized water, stirring, get triphenyl phosphate solution; in chitosan solution, stirring, add calcium nitrite solution, stirring, add triphenyl phosphate solution, stirring 40min, static, take supernatant, centrifugal, washing, drying, get coated chitosan calcium nitrite;

[0046] Step two: preparation of modified bentonite:

[0047] Take 5g bentonite, 40mL deionized water, stirring, add 60mL concentration of 2.5% cetyl trimethyl ammonium bromide solution, stirring, heating to 50℃, reaction 2h, washing, drying, get pretreated bentonite;

[0048] Take 2g coated chitosan calcium nitrite, 50mL deionized water, stirring, add 5g pretreated bentonite, stirring 14h, get modified bentonite.

[0049] The mass ratio of coated chitosan calcium nitrite and pretreated bentonite is 2:5.

[0050] Step three: preparation of water absorbing resin:

[0051] Take 100g acrylic acid, add 40% sodium hydroxide aqueous solution, adjust pH value to 6, add 5g potato starch, 5g modified bentonite, 0.01g concentration of 1% potassium persulfate solution, 0.01g concentration of 1% N-N methylene double acrylamide solution, stirring, heating to 40℃, stirring 2h, then heating to 70℃, stirring 40min, granulation, drying, crushing, get water absorbing resin;

[0052] Step four: preparation of environment-friendly high performance concrete:

[0053] The silicate cement, fine aggregate, coarse aggregate, polyethylene glycol defoaming agent, stirring, add fly ash, water, polycarboxylic acid water reducer, stirring 20min, add water absorbing resin, diatomite, stirring 25min, get a kind of environment-friendly high performance concrete;

[0054] The environment-friendly high performance concrete, by weight parts, includes the following ingredients:

[0055] 400 parts of silicate cement, 470 parts of fine aggregate, 840 parts of coarse aggregate, 2 parts of polyethylene glycol defoaming agent, 70 parts of fly ash, 170 parts of water, 11 parts of polycarboxylic acid water reducer, 18 parts of water absorbing resin, 30 parts of diatomite.

[0056] Embodiment 3: a preparation process of an environmentally friendly high-performance concrete, comprising the following steps:

[0057] Step one: preparation of calcium nitrite coated with chitosan:

[0058] Take 0.2g chitosan, 50mL of 1% acetic acid solution, stir evenly to obtain chitosan solution; take 0.2g calcium nitrite, 50mL of deionized water, stir evenly to obtain calcium nitrite solution; take 2mg triphenyl phosphate, 20mL of deionized water, stir evenly to obtain triphenyl phosphate solution; add calcium nitrite solution to chitosan solution, stir evenly, add triphenyl phosphate solution, stir for 50min, stand, take supernatant, centrifuge, wash, dry to obtain calcium nitrite coated with chitosan;

[0059] Step two: preparation of modified bentonite:

[0060] Take 5g bentonite, 40mL of deionized water, stir evenly, add 60mL of 2.5% cetyltrimethylammonium bromide solution, stir evenly, heat to 55℃, react for 3h, wash, dry to obtain pretreated bentonite;

[0061] Take 2g calcium nitrite coated with chitosan, 50mL of deionized water, stir evenly, add 6g pretreated bentonite, stir for 16h to obtain modified bentonite.

[0062] The mass ratio of calcium nitrite coated with chitosan to pretreated bentonite is 2:6.

[0063] Step three: preparation of water absorbing resin:

[0064] Take 100g acrylic acid, add 40% sodium hydroxide aqueous solution, adjust pH value to 7, add 5g potato starch, 5g modified bentonite, 0.01g 1% potassium persulfate solution, 0.01g 1% N-N methylene bisacrylamide solution, stir evenly, heat to 45℃, stir for 3h, then heat to 75℃, stir for 80min, granulate, dry, crush to obtain water absorbing resin;

[0065] Step four: preparation of environmentally friendly high-performance concrete:

[0066] Mix silicate cement, fine aggregate, coarse aggregate and polyethylene glycol defoaming agent, add fly ash, water and polycarboxylic acid water reducer, stir for 25min, add water absorbing resin and diatomite, stir for 30min to obtain an environmentally friendly high-performance concrete;

[0067] The environmentally friendly high-performance concrete comprises the following ingredients by weight:

[0068] 480 parts of Portland cement, 500 parts of fine aggregate, 900 parts of coarse aggregate, 3 parts of polyethylene glycol defoaming agent, 80 parts of fly ash, 220 parts of water, 14 parts of polycarboxylic acid water reducer, 20 parts of water absorbing resin, 35 parts of diatomite.

[0069] Comparative Example 1: calcium nitrite without coating with chitosan, and the rest is the same as Example 1.

[0070] Step one: preparation of pretreated bentonite:

[0071] Take 5g of bentonite, 40mL of deionized water, stir evenly, add 60mL of 2.5% concentration of cetyltrimethylammonium bromide solution, stir evenly, heat to 53℃, react for 2.5h, wash, dry, get pretreated bentonite;

[0072] Step two: preparation of water absorbing resin:

[0073] Take 100g of acrylic acid, add 40% sodium hydroxide aqueous solution, adjust the pH value to 6.5, add 5g of potato starch, 5g of pretreated bentonite, 0.01g of 1% potassium persulfate solution, 0.01g of 1% N-N methylene bisacrylamide solution, stir evenly, heat to 43℃, stir for 2.5h, then heat to 73℃, stir for 60min, granulation, drying, crushing, get water absorbing resin;

[0074] Step three: preparation of environment-friendly high-performance concrete:

[0075] Mix Portland cement, fine aggregate, coarse aggregate, polyethylene glycol defoaming agent, add fly ash, water, polycarboxylic acid water reducer, stir for 23min, add water absorbing resin, diatomite, stir for 28min, get an environment-friendly high-performance concrete;

[0076] The environment-friendly high-performance concrete, by weight parts, includes the following ingredients:

[0077] 460 parts of Portland cement, 480 parts of fine aggregate, 880 parts of coarse aggregate, 2.5 parts of polyethylene glycol defoaming agent, 75 parts of fly ash, 200 parts of water, 13 parts of polycarboxylic acid water reducer, 19 parts of water absorbing resin, 32 parts of diatomite.

[0078] Comparative Example 2: calcium nitrite without coating with chitosan, and the rest is the same as Example 1.

[0079] Step one: preparation of modified bentonite:

[0080] Take 5g bentonite, 40mL deionized water, stir evenly, add 60mL concentration of 2.5% cetyltrimethylammonium bromide solution, stir evenly, heat to 53℃, react for 2.5h, wash, dry, get pretreated bentonite;

[0081] Take 2g calcium nitrite, 50mL deionized water, stir evenly, add 5.5g pretreated bentonite, stir for 15h, get modified bentonite.

[0082] The mass ratio of calcium nitrite and pretreated bentonite is 2:5.5.

[0083] Step two: preparation of water absorbing resin:

[0084] Take 100g acrylic acid, add 40% sodium hydroxide aqueous solution, adjust pH value to 6.5, add 5g potato starch, 5g modified bentonite, 0.01g concentration of 1% potassium persulfate solution, 0.01g concentration of 1% N-N methylene double acrylamide solution, stir evenly, heat to 43℃, stir for 2.5h, then heat to 73℃, stir for 60min, granulation, drying, crushing, get water absorbing resin;

[0085] Step three: preparation of environment-friendly high-performance concrete:

[0086] Mix silicate cement, fine aggregate, coarse aggregate, polyethylene glycol defoaming agent, add fly ash, water, polycarboxylic acid water reducer, stir for 23min, add water absorbing resin, diatomite, stir for 28min, get an environment-friendly high-performance concrete;

[0087] The environment-friendly high-performance concrete, by weight, includes the following ingredients:

[0088] 460 parts of silicate cement, 480 parts of fine aggregate, 880 parts of coarse aggregate, 2.5 parts of polyethylene glycol defoaming agent, 75 parts of fly ash, 200 parts of water, 13 parts of polycarboxylic acid water reducer, 19 parts of water absorbing resin, 32 parts of diatomite.

[0089] Comparative example 3: control the mass ratio of cationic starch coated calcium nitrite and pretreated bentonite is 2:8, the rest is the same as example 1.

[0090] Step one: preparation of cationic starch coated calcium nitrite:

[0091] Take 0.2g chitosan, 50mL concentration of 1% acetic acid solution, stirring, get chitosan solution; take 0.2g calcium nitrite, 50mL deionized water, stirring, get calcium nitrite solution; take 2mg triphenyl phosphate, 20mL deionized water, stirring, get triphenyl phosphate solution; in chitosan solution, stirring, add calcium nitrite solution, stirring, add triphenyl phosphate solution, stirring 45min, standing, take supernatant, centrifugal, washing, drying, get coated chitosan calcium nitrite;

[0092] Step two: preparation of modified bentonite:

[0093] Take 5g bentonite, 40mL deionized water, stirring, add 60mL concentration of 2.5% cetyl trimethyl ammonium bromide solution, stirring, heating to 53℃, reaction 2.5h, washing, drying, get pretreated bentonite;

[0094] Take 2g coated chitosan calcium nitrite, 50mL deionized water, stirring, add 8g pretreated bentonite, stirring 15h, get modified bentonite.

[0095] The mass ratio of coated chitosan calcium nitrite and pretreated bentonite is 2:8.

[0096] Step three: preparation of water absorbing resin:

[0097] Take 100g acrylic acid, add 40% sodium hydroxide aqueous solution, adjust pH to 6.5, add 5g potato starch, 5g modified bentonite, 0.01g concentration of 1% potassium persulfate solution, 0.01g concentration of 1% N-N methylene double acrylamide solution, stirring, heating to 43℃, stirring 2.5h, then heating to 73℃, stirring 60min, granulation, drying, crushing, get water absorbing resin;

[0098] Step four: preparation of environment-friendly high performance concrete:

[0099] Mix silicate cement, fine aggregate, coarse aggregate, polyethylene glycol defoamer, add fly ash, water, polycarboxylic acid water reducer, stirring 23min, add water absorbing resin, diatomite, stirring 28min, get an environment-friendly high performance concrete;

[0100] The environment-friendly high performance concrete, by weight parts, includes the following ingredients:

[0101] 460 parts of silicate cement, 480 parts of fine aggregate, 880 parts of coarse aggregate, 2.5 parts of polyethylene glycol defoamer, 75 parts of fly ash, 200 parts of water, 13 parts of polycarboxylic acid water reducer, 19 parts of water absorbing resin, 32 parts of diatomite.

[0102] Experiment:

[0103] The concrete prepared by example 1-3 and comparative example 1-3 is tested for performance, the concrete is poured into a mold to obtain a test piece, the test piece is placed in a room at a temperature of 20 DEG C and a relative humidity of 55% for 1 day, and then demolded, and the test piece is placed in a room at a temperature of 20 DEG C and a relative humidity of 95% for 28 days. The impermeability grade of the test piece is tested according to the step-by-step pressure method in GB / T50082-2009, the test piece is a circular truncated cone with an upper opening inner diameter of 175 mm, a lower opening inner diameter of 185 mm, and a height of 150 mm. The crack resistance of the test piece is tested according to the early crack resistance experiment in GB / T50082-2009, the test piece has a size of 800 mm x 600 mm x 100 mm, the test temperature is 20 DEG C, the relative humidity is 60%, and the time and crack length of the test piece are tested.

[0104]

[0105] Conclusion: According to the comparison of the data, the performance of the concrete prepared by the application is excellent, and the crack resistance and impermeability are better. Comparative example 1 does not add calcium nitrite coated with chitosan, the porosity of the pore structure of the concrete is reduced, and the impermeability and crack resistance of the concrete are reduced. Comparative example 2 does not coat chitosan on calcium nitrite, the dispersibility of bentonite in the water absorbing resin is poor, and the impermeability and crack resistance of the concrete are reduced. Comparative example 3 controls the mass ratio of calcium nitrite coated with chitosan and pretreated bentonite to be 2:8, the proportion of calcium nitrite coated with chitosan is reduced, and the impermeability grade of the concrete is P9, and the crack resistance is also reduced.

[0106] Finally, it should be noted that: the above only describes the preferred embodiments of the application, and is not used to limit the application, although the application has been described in detail with reference to the foregoing embodiments, and for those skilled in the art, the technical solutions recorded in the foregoing embodiments can be modified, or some technical features can be replaced. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the application shall be included in the protection scope of the application.

Claims

1. A preparation process for environmentally friendly high-performance concrete, characterized in that: It comprises the following steps: Step one: take acrylic acid, add sodium hydroxide aqueous solution, adjust the pH value to 6-7, add potato starch, modified bentonite, potassium persulfate solution, N-N methylene double acrylamide solution, stir evenly, warm up to 40-45℃, stir, then warm up to 70-75℃, continue to stir, granulate, dry, crush, get water absorbing resin; Step two: mix silicate cement, fine aggregate, coarse aggregate, defoaming agent, stir evenly, add fly ash, water, polycarboxylic acid water reducer, stir for 20-25min, add water absorbing resin, diatomite, stir for 25-30min, get an environment-friendly high-performance concrete; The preparation method of the modified bentonite comprises the following steps: S1: take bentonite, deionized water, stir evenly, add cetyltrimethylammonium bromide solution, stir evenly, warm up to 50-55℃, react for 2-3h, wash, dry, get pretreated bentonite; S2: take calcium nitrite coated with chitosan, deionized water, stir evenly, add pretreated bentonite, stir for 14-16h, get modified bentonite; The preparation method of the calcium nitrite coated with chitosan is: take chitosan, acetic acid solution, stir evenly, get chitosan solution; take calcium nitrite, deionized water, stir evenly, get calcium nitrite solution; take triphenyl phosphate, deionized water, stir evenly, get triphenyl phosphate solution; add calcium nitrite solution to the chitosan solution, stir evenly, add triphenyl phosphate solution, stir for 40-50min, stand, take supernatant, centrifuge, wash, dry, get calcium nitrite coated with chitosan.

2. The preparation process of the environment-friendly high-performance concrete according to claim 1, characterized in that: The environment-friendly high-performance concrete comprises the following ingredients by weight: 400-480 parts of silicate cement, 470-500 parts of fine aggregate, 840-900 parts of coarse aggregate, 2-3 parts of defoaming agent, 70-80 parts of fly ash, 170-220 parts of water, 11-14 parts of polycarboxylic acid water reducer, 18-20 parts of water absorbing resin, 30-35 parts of diatomite.

3. The preparation process of the environment-friendly high-performance concrete according to claim 1, characterized in that: The defoaming agent is any one of polypropylene glycol and polyethylene glycol.

4. The preparation process of the environment-friendly high-performance concrete according to claim 1, characterized in that: The particle size of the diatomite is 650-700 mesh.

5. The preparation process of the environment-friendly high-performance concrete according to claim 1, characterized in that: The particle size of the bentonite is 250-300 mesh.

6. The preparation process of the environment-friendly high-performance concrete according to claim 1, characterized in that: The mass ratio of the calcium nitrite coated with chitosan to the pretreated bentonite is 2: (5-6).

7. An environment-friendly high-performance concrete prepared by the preparation process of the environment-friendly high-performance concrete according to any one of claims 1-6.

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