High-performance coal gangue pavement concrete and preparation method thereof

Abstract

The application relates to the technical field of concrete, and discloses high-performance coal gangue pavement concrete and a preparation method thereof. The high-performance coal gangue pavement concrete comprises the following components by weight: 145-150 parts of coal gangue, 135-145 parts of sand, 25-30 parts of water, 45-55 parts of cement, 10-15 parts of fly ash, 25-30 parts of a modifier and 0.3-0.5 parts of a water reducing agent. The coal gangue is pretreated coal gangue, which is obtained by treating coal gangue with acrylic acid modified polyester resin and polyester modified acrylic acid resin. The hydroxyl group of the acrylic acid modified polyester resin is 7 mgKOH / g. The hydroxyl value of the polyester modified acrylic acid resin is 4 mgKOH / g. The raw material of the modifier comprises nano silicon dioxide and steel fibers. The technical scheme solves the problem of low mechanical strength of coal gangue pavement concrete in the related art.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of concrete, in particular to a high-performance coal gangue pavement concrete and a preparation method thereof. BACKGROUND

[0002] As the core bearing layer of the traffic infrastructure, the pavement needs to continuously bear complex and high-strength loads, and the mechanical strength of the pavement concrete directly determines the structural integrity and long-term service ability of the road, and is related to the economy and traffic safety of the pavement engineering.

[0003] In the field of road construction, the traditional pavement concrete mainly relies on natural aggregates such as river sand and gravel, however, with the continuous advancement of infrastructure construction, the demand for natural aggregates has increased sharply, and the price has risen continuously, resulting in the increase of the cost of the concrete. Coal gangue is a kind of solid waste discharged during coal mining and coal washing, so a large amount of coal gangue will be produced along with the production of coal. The long-term storage of coal gangue not only occupies land, but also may pollute the environment, therefore, the application of coal gangue in pavement concrete can not only realize the resource utilization of coal gangue, but also reduce the cost of road construction.

[0004] However, the physicochemical properties of coal gangue in the coal gangue pavement concrete are different from those of natural sand and stone, which may result in poor mechanical strength of the pavement concrete, thereby limiting the improvement of the mechanical strength of the coal gangue pavement concrete, and to some extent, affecting the wide application of the coal gangue pavement concrete. SUMMARY

[0005] The present application provides a high-performance coal gangue pavement concrete and a preparation method thereof, which solves the problem of low mechanical strength of the coal gangue concrete in the related art.

[0006] The technical scheme of the present application is as follows:

[0007] The present application provides a high-performance coal gangue pavement concrete, which comprises the following components by weight: coal gangue 145-150 parts, sand 135-145 parts, water 25-30 parts, cement 45-55 parts, fly ash 10-15 parts, modifier 25-30 parts, and water reducing agent 0.3-0.5 parts.

[0008] The coal gangue is pretreated coal gangue, which is obtained by treating coal gangue with acrylic acid modified polyester resin and polyester modified acrylic acid resin; the hydroxyl group of the acrylic acid modified polyester resin is 7mgKOH / g; and the hydroxyl value of the polyester modified acrylic acid resin is 4mgKOH / g.

[0009] The raw materials of the modifier include nano-silicon dioxide and steel fibers.

[0010] As a further technical solution, the mass ratio of the acrylic modified polyester resin and the polyester modified acrylic resin is 5:2~3, preferably 2:1.

[0011] The mass ratio of the acrylic modified polyester resin and the polyester modified acrylic resin for the pretreatment of coal gangue in the application is 5:2~3, and when the mass ratio of the acrylic modified polyester resin and the polyester modified acrylic resin is within the limited range, the compressive strength of the coal gangue pavement concrete is significantly improved, and when the mass ratio of the two is outside the limited range, the compressive strength of the coal gangue pavement concrete is reduced.

[0012] As a further technical solution, the mass of the acrylic modified polyester resin and the polyester modified acrylic resin is 3%~6% of the mass of the coal gangue, preferably 5%.

[0013] As a further technical solution, the preparation method of the pretreated coal gangue comprises the following steps:

[0014] S1, after calcining the coal gangue, the calcined coal gangue is obtained;

[0015] S2, the acrylic modified polyester resin and the calcined coal gangue are added to ethyl acetate and mixed to obtain a mixture;

[0016] S3, the polyester modified acrylic resin is added to the mixture and mixed, and then dried to obtain the pretreated coal gangue.

[0017] As a further technical solution, the calcining temperature is 600~700℃, and the calcining time is 0.5~1h.

[0018] As a further technical solution, in step S2, the mixing temperature is 40~50℃, and the mixing time is 1~2h.

[0019] As a further technical solution, in step S3, the mixing temperature is 40~50℃, and the mixing time is 0.5~1h.

[0020] As a further technical solution, the raw material of the modifier further comprises trimethylchlorosilane and diphenyl-4-carboxylic acid methyl ester.

[0021] The modifier comprises nano-silicon dioxide, steel fiber, trimethylchlorosilane and methyl biphenyl-4-carboxylate, the addition of nano-silicon dioxide and steel fiber can synergistically improve the compressive strength of coal gangue pavement concrete, but nano-silicon dioxide may appear agglomeration phenomenon in the mixing process of coal gangue pavement concrete, the addition of trimethylchlorosilane and methyl biphenyl-4-carboxylate can effectively solve the agglomeration phenomenon of nano-silicon dioxide in the mixing process, and then the modification effect of nano-silicon dioxide on coal gangue pavement concrete is better, and the compressive strength of coal gangue pavement concrete is further improved.

[0022] As a further technical solution, the mass ratio of the nano-silicon dioxide, steel fiber, trimethylchlorosilane and methyl biphenyl-4-carboxylate is 20:10:0.5:0.1-0.2.

[0023] As a further technical solution, after the nano-silicon dioxide, trimethylchlorosilane and methyl biphenyl-4-carboxylate are added to the solution and mixed, drying is carried out to obtain pretreated nano-silicon dioxide, and the pretreated nano-silicon dioxide and steel fiber are mixed to obtain the modifier.

[0024] As a further technical solution, the solution is anhydrous ethanol.

[0025] As a further technical solution, the water reducing agent is a polycarboxylic acid water reducing agent.

[0026] In the application, the addition of coal gangue can adsorb more water, so that the coal gangue concrete needs a large amount of water in the mixing process, and has poor fluidity, which is specifically manifested as easy caking after mixing, difficult pumping and the like, and can also cause construction defects and reduction of the mechanical strength of coal gangue concrete in the construction process. The addition of the polycarboxylic acid water reducing agent not only solves the problem of large water demand of coal gangue, but also reduces the water-binder ratio, so that the coal gangue concrete can have high mechanical strength and comprehensive performance.

[0027] As a further technical solution, the cement is P.O 42.5 Portland cement.

[0028] The application further provides a preparation method of high-performance coal gangue pavement concrete.

[0029] The working principle and beneficial effects of the application are as follows:

[0030] The coal gangue in the coal gangue pavement concrete is pretreated by the acrylic modified polyester resin and the polyester modified acrylic resin in the application, the pretreated coal gangue is obtained, and the compressive strength of the coal gangue pavement concrete is improved. In the prior art, the coal gangue pavement concrete has the problem of low compressive strength. In the application, the pretreated coal gangue obtained after the pretreatment of the coal gangue by the acrylic modified polyester resin and the polyester modified acrylic resin is added into the pavement concrete. Compared with the coal gangue without pretreatment, the problem of mechanical strength reduction caused by the different physicochemical properties of the coal gangue and the natural sandstone can be reduced, and the compressive strength of the coal gangue pavement concrete is improved, and the application range of the coal gangue pavement concrete is expanded. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the embodiments of the application. 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 a person of ordinary skill in the art without creative work are within the protection scope of the application.

[0032] In the following examples and comparative examples:

[0033] The polyester modified acrylic resin is model SGR-2600, the hydroxyl content is 4 mgKOH / g, the acid value is 1 mgKOH / g, the acrylic modified polyester resin is model SGR-2400, the hydroxyl content is 7 mgKOH / g, and the acid value is 1 mgKOH / g; all are purchased from Guangzhou Changhao Trading Co., Ltd.;

[0034] Cement: P.O 42.5 grade Portland cement; fly ash: I grade fly ash; coal gangue: particle size 325 mesh; sand is composed of sandstone with a particle size of 2-3 mm and sandstone with a particle size of 8-10 mm in a mass ratio of 1.5:1; nano silicon dioxide: average particle size 20 nm; steel fiber: end hook type, length 25 mm, diameter 0.5 mm, manufacturer: Anping Zhihui Engineering Material Co., Ltd.; polycarboxylic acid water reducing agent: model PC-1021, manufacturer: Zhengzhou Chengrui Chemical Product Co., Ltd.

[0035] Example 1

[0036] A high-performance coal gangue pavement concrete comprises the following components by weight: coal gangue 145 parts, sand 135 parts, water 25 parts, cement 45 parts, fly ash 10 parts, modifier 25 parts, and water reducing agent 0.3 parts; wherein the modifier is composed of nano silicon dioxide and steel fiber in a mass ratio of 2:1.

[0037] A preparation method of a high-performance coal gangue pavement concrete comprises the following steps: mixing the above-mentioned raw materials uniformly to obtain the high-performance coal gangue pavement concrete.

[0038] wherein the coal gangue is pretreated coal gangue, and a preparation method of the pretreated coal gangue comprises the following steps:

[0039] S1, calcining the coal gangue at 700 DEG C for 0.5h to obtain calcined coal gangue;

[0040] S2, adding the calcined coal gangue and acrylic modified polyester resin into ethyl acetate, mixing at 40 DEG C for 2h to obtain a mixture;

[0041] S3, adding polyester modified acrylic resin into the mixture, mixing at 40 DEG C for 1h, and drying to obtain the pretreated coal gangue;

[0042] The total mass of the acrylic modified polyester resin and the polyester modified acrylic resin is 5% of the mass of the coal gangue, the mass ratio of the acrylic modified polyester resin to the polyester modified acrylic resin is 5:2, and the mass-volume ratio of the coal gangue to ethyl acetate is 1g:9mL.

[0043] Example 2

[0044] A high-performance coal gangue pavement concrete comprises the following components by weight: coal gangue 147 parts, sand 140 parts, water 28 parts, cement 50 parts, fly ash 12 parts, modifier 28 parts, and water reducing agent 0.4 parts; wherein the modifier is composed of nano-silicon dioxide and steel fibers in a mass ratio of 2:1;

[0045] A preparation method of a high-performance coal gangue pavement concrete comprises the following steps: mixing the above-mentioned raw materials uniformly to obtain the high-performance coal gangue pavement concrete.

[0046] wherein the coal gangue is pretreated coal gangue, and a preparation method of the pretreated coal gangue comprises the following steps:

[0047] S1, calcining the coal gangue at 700 DEG C for 0.5h to obtain calcined coal gangue;

[0048] S2, adding the calcined coal gangue and acrylic modified polyester resin into ethyl acetate, mixing at 40 DEG C for 2h to obtain a mixture;

[0049] S3, adding polyester modified acrylic resin into the mixture, mixing at 50 DEG C for 1h, and drying to obtain the pretreated coal gangue;

[0050] The total mass of the acrylic modified polyester resin and the polyester modified acrylic resin is 5% of the mass of the coal gangue, the mass ratio of the acrylic modified polyester resin to the polyester modified acrylic resin is 5:2, and the mass-volume ratio of the coal gangue to ethyl acetate is 1g:9mL.

[0051] Example 3

[0052] A high-performance coal gangue pavement concrete, comprising the following components by weight: coal gangue 150 parts, sand 145 parts, water 30 parts, cement 55 parts, fly ash 15 parts, modifier 30 parts, and water reducing agent 0.5 parts; wherein the modifier is composed of nano-silicon dioxide and steel fibers in a mass ratio of 2:1.

[0053] A preparation method of a high-performance coal gangue pavement concrete, comprising the following steps: uniformly mixing the above-mentioned raw materials to obtain the high-performance coal gangue pavement concrete.

[0054] The coal gangue is pretreated coal gangue, and the preparation method of the pretreated coal gangue comprises the following steps:

[0055] S1, calcining the coal gangue at 700 DEG C for 0.5 h to obtain calcined coal gangue;

[0056] S2, adding the calcined coal gangue and acrylic modified polyester resin into ethyl acetate and mixing at 40 DEG C for 2 h to obtain a mixture;

[0057] S3, adding polyester modified acrylic resin into the mixture and mixing at 40 DEG C for 1 h, and then drying to obtain the pretreated coal gangue;

[0058] The mass sum of the acrylic modified polyester resin and the polyester modified acrylic resin is 5% of the mass of the coal gangue, the mass ratio of the acrylic modified polyester resin to the polyester modified acrylic resin is 5:2, and the mass-volume ratio of the coal gangue to ethyl acetate is 1 g:9 mL.

[0059] Example 4

[0060] Compared with example 1, the difference of example 4 is only in the preparation method of the pretreated coal gangue, and the preparation method of the pretreated coal gangue comprises the following steps:

[0061] S1, calcining the coal gangue at 700 DEG C for 0.5 h to obtain calcined coal gangue;

[0062] S2, adding the calcined coal gangue and polyester modified acrylic resin into ethyl acetate and mixing at 40 DEG C for 2 h to obtain a mixture;

[0063] S3, adding acrylic modified polyester resin into the mixture and mixing at 40 DEG C for 1 h, and then drying to obtain the pretreated coal gangue;

[0064] The mass sum of the acrylic modified polyester resin and the polyester modified acrylic resin is 5% of the mass of the coal gangue, the mass ratio of the acrylic modified polyester resin to the polyester modified acrylic resin is 5:2, and the mass-volume ratio of the coal gangue to ethyl acetate is 1 g:9 mL.

[0065] Example 5

[0066] The difference between the present embodiment and example 1 is only the preparation method of the pretreated coal gangue, the preparation method of the pretreated coal gangue of the present embodiment comprises the following steps:

[0067] S1, calcining the coal gangue at 700℃ for 0.5h to obtain calcined coal gangue;

[0068] S2, adding the calcined coal gangue, polyester modified acrylic resin and acrylic modified polyester resin into ethyl acetate, mixing at 40℃ for 3h, and then drying to obtain the pretreated coal gangue;

[0069] The mass ratio of the acrylic modified polyester resin to the polyester modified acrylic resin is 5:2, and the mass-volume ratio of the coal gangue to ethyl acetate is 1g:9mL.

[0070] Example 6

[0071] The difference between the present embodiment and example 1 is only that the mass ratio of the acrylic modified polyester resin to the polyester modified acrylic resin is 5:2.5.

[0072] Example 7

[0073] The difference between the present embodiment and example 1 is only that the mass ratio of the acrylic modified polyester resin to the polyester modified acrylic resin is 5:3.

[0074] Example 8

[0075] The difference between the present embodiment and example 1 is only the modifier, the preparation method of the modifier of the present embodiment comprises the following steps: adding nano-silicon dioxide into anhydrous ethanol and uniformly dispersing, then adding trimethylchlorosilane, mixing at 40℃ for 1h, and then drying to obtain pretreated nano-silicon dioxide, mixing the pretreated nano-silicon dioxide and steel fibers to obtain the modifier; wherein the mass ratio of the nano-silicon dioxide, the steel fibers and the trimethylchlorosilane is 20:10:0.6; the mass-volume ratio of the nano-silicon dioxide to the anhydrous ethanol is 1g:6mL.

[0076] Example 9

[0077] The difference between the embodiment and example 1 is only the modifier, the preparation method of the modifier of the embodiment comprises the following steps: after the nanosilica is uniformly dispersed in anhydrous ethanol, methyl biphenyl-4-carboxylate is added, and mixing is performed at 40 DEG C for 1h, and then drying is performed to obtain pretreated nanosilica, and the pretreated nanosilica and steel fibers are mixed to obtain the modifier; wherein the mass ratio of nanosilica, steel fiber, methyl biphenyl-4-carboxylate is 20:10:0.6; the mass-volume ratio of nanosilica and anhydrous ethanol is 1g:6ml.

[0078] Example 10

[0079] The difference between the embodiment and example 1 is only the modifier, the preparation method of the modifier of the embodiment comprises the following steps: after the nanosilica is uniformly dispersed in anhydrous ethanol, methyl biphenyl-4-carboxylate is added, and mixing is performed at 40 DEG C for 1h, and then drying is performed to obtain pretreated nanosilica, and the pretreated nanosilica and steel fibers are mixed to obtain the modifier; wherein the mass ratio of nanosilica, steel fiber, methyl biphenyl-4-carboxylate is 20:10:0.6; the mass-volume ratio of nanosilica and anhydrous ethanol is 1g:6ml.

[0080] Comparative example 1

[0081] The difference between the embodiment and example 4 is only the preparation method of the pretreated coal gangue, the preparation method of the pretreated coal gangue in the comparative example comprises the following steps:

[0082] S1, the coal gangue is calcined at 700 DEG C for 0.5h to obtain calcined coal gangue;

[0083] S2, the calcined coal gangue and acrylic modified polyester resin are added to ethyl acetate, mixed at 40 DEG C for 3h, and then dried to obtain pretreated coal gangue;

[0084] The acrylic modified polyester resin is 5% of the mass of the coal gangue, and the mass-volume ratio of the coal gangue and ethyl acetate is 1g:9ml.

[0085] Comparative example 2

[0086] The difference between the embodiment and example 4 is only the preparation method of the pretreated coal gangue, the preparation method of the pretreated coal gangue in the comparative example comprises the following steps:

[0087] S1, the coal gangue is calcined at 700 DEG C for 0.5h to obtain calcined coal gangue;

[0088] S2, the calcined coal gangue, the polyester modified acrylic resin is added into ethyl acetate, mixed at 40℃ for 3h, and then dried to obtain the pretreated coal gangue;

[0089] The polyester modified acrylic resin is 5% of the mass of the coal gangue, and the mass-volume ratio of the coal gangue and the ethyl acetate is 1g:9mL.

[0090] Comparative Example 3

[0091] Compared with Example 4, the difference of the present comparative example is only that no modifier is added.

[0092] Experimental Example

[0093] The performance of the coal gangue pavement concrete in Examples 1-10 and Comparative Examples 1-3 is determined, and the determination method is as follows:

[0094] (1) The compressive strength, splitting tensile strength and water absorption rate of the coal gangue pavement concrete are determined according to the determination method in GB / T 50081-2019 “Standard for Testing Methods of Mechanical Properties of Ordinary Concrete”; wherein, the loading speed is 0.5MPa / s when determining the compressive strength, and the loading speed is 0.05MPa / s when determining the splitting tensile strength; the samples used in determining the compressive strength, splitting tensile strength and water absorption rate are all 100mm×100mm×100mm cubes cured for 28d;

[0095] (2) The sulfate resistance and frost resistance are determined according to GB / T 50082-2009 “Standard for Testing Methods of Long-term Performance and Durability of Ordinary Concrete”; the slow freezing method is selected for testing the frost resistance, and the samples used in testing the sulfate resistance and frost resistance are all 100mm×100mm×100mm cubes cured for 28d;

[0096] The determination results are shown in Tables 1-4.

[0097] Table 1 Determination results of compressive strength of coal gangue pavement concrete

[0098]

[0099] As shown in Table 1, the compressive strength of the coal gangue pavement concrete in Examples 1-7 is higher than that in Comparative Examples 1-3, which shows that in the present application, the acrylic modified polyester resin and the polyester modified acrylic resin can be used to treat the coal gangue, so as to improve the compressive strength of the coal gangue pavement concrete.

[0100] Table 2 Determination results of splitting tensile strength of coal gangue pavement concrete

[0101]

[0102] From table 2, the splitting tensile strength of the coal gangue pavement concrete in examples 8~10 is higher than that in examples 1, 4~5, which shows that the addition of the pretreated nano-silica in the modifier can improve the splitting tensile strength of the coal gangue pavement concrete.

[0103] Table 3: Water absorption rate determination results of the coal gangue pavement concrete

[0104]

[0105] From table 3, the water absorption rate of the coal gangue pavement concrete in examples 8~10 is lower than that in example 1, which shows that the addition of the pretreated nano-silica in the modifier can reduce the water absorption rate of the coal gangue pavement concrete.

[0106] Table 4: Determination results of the erosion resistance and frost resistance of the coal gangue pavement concrete

[0107]

[0108] From table 4, the coal gangue pavement concrete in the application also has high erosion resistance and frost resistance, which can prolong the service life of the coal gangue pavement concrete and reduce the maintenance cost.

[0109] The above only is the preferred embodiment of the present application, and does not limit the present application, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A high-performance coal gangue pavement concrete, characterized in that, The raw materials include the following components by weight: 145-150 parts coal gangue, 135-145 parts sand, 25-30 parts water, 45-55 parts cement, 10-15 parts fly ash, 25-30 parts modifier, and 0.3-0.5 parts water-reducing agent. The coal gangue is pretreated coal gangue, which is obtained by treating coal gangue with acrylic acid-modified polyester resin and polyester-modified acrylic resin; the hydroxyl value of the acrylic acid-modified polyester resin is 7 mgKOH / g; the hydroxyl value of the polyester-modified acrylic resin is 4 mgKOH / g. The raw materials for the modifier include nano-silica, steel fiber, trimethylchlorosilane, and biphenyl-4-carboxylic acid methyl ester; The mass ratio of the nano-silica, steel fiber, trimethylchlorosilane, and biphenyl-4-carboxylic acid methyl ester is 20:10:0.5:0.1~0.

2.

2. The high-performance coal gangue pavement concrete according to claim 1, characterized in that, The mass ratio of the acrylic-modified polyester resin to the polyester-modified acrylic resin is 5:2~3.

3. The high-performance coal gangue pavement concrete according to claim 1, characterized in that, The combined mass of the acrylic-modified polyester resin and the polyester-modified acrylic resin is 3% to 6% of the mass of the coal gangue.

4. The high-performance coal gangue pavement concrete according to claim 1, characterized in that, The method for preparing the pretreated coal gangue includes the following steps: S1. After calcining coal gangue, calcined coal gangue is obtained. S2. Acrylic acid-modified polyester resin and calcined coal gangue are added to ethyl acetate and mixed to obtain a mixture; S3. Add polyester-modified acrylic resin to the mixture, mix, and then dry to obtain pretreated coal gangue.

5. The high-performance coal gangue pavement concrete according to claim 1, characterized in that, The method for preparing the modifier includes the following steps: adding nano-silica, trimethylchlorosilane and biphenyl-4-carboxylic acid methyl ester into a solution, mixing and drying to obtain pretreated nano-silica; mixing the pretreated nano-silica with steel fibers to obtain the modifier.

6. The high-performance coal gangue pavement concrete according to claim 1, characterized in that, The water-reducing agent is a polycarboxylate water-reducing agent.

7. A high-performance coal gangue pavement concrete according to claim 1, characterized in that, The cement is P.O42.5 silicate cement.

8. A method for preparing high-performance coal gangue pavement concrete, used to prepare the high-performance coal gangue pavement concrete as described in any one of claims 1 to 7, characterized in that, Includes the following steps: After the raw materials are mixed evenly, high-performance coal gangue pavement concrete is obtained.

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