Concrete prepared by using tunnel waste and preparation method thereof

Abstract

The invention discloses a concrete prepared by using tunnel waste and a preparation method thereof, and relates to the field of building materials and engineering. The concrete prepared by using the tunnel waste comprises the following components by weight: 1800-2200 parts of tunnel waste, 300-450 parts of cement, 6-18 parts of polyaluminium ferric chloride, 2-10 parts of carboxymethyl cellulose, 4-17 parts of water reducer, and 135-225 parts of water. The invention does not need to firstly perform secondary treatments such as crushing and shaping, washing and demuding the tunnel waste, and directly uses it to prepare concrete when the particle size is satisfied, so that conventional concrete construction and mechanical properties can be achieved, and the 28d cubic compressive strength can reach more than 34MPa.

Description

Technical Field

[0001] The invention relates to the field of building materials and engineering, and in particular to concrete prepared by utilizing tunnel waste slag and a preparation method thereof. Technical Background

[0002] At present, most tunnel excavation materials are regarded as waste and directly piled up in waste dumps. The accumulation of large amounts of tunnel waste will not only cause land, resource and environmental problems, but improper disposal will also cause safety hazards such as landslides and mud-rock flows. If most of the tunnel waste can be used as concrete aggregate resources, it will effectively alleviate the shortage of natural aggregates for concrete, while also saving mineral resources, reducing construction costs and reducing the impact on the environment.

[0003] Due to its poor particle grading, irregular particle shape, high mud content and other weaknesses, tunnel waste needs to be crushed, shaped, washed and de-mudged before it can be used as concrete aggregate according to conventional engineering treatment measures, otherwise it cannot meet the construction and mechanical properties requirements of conventional concrete. The use of traditional treatment methods will undoubtedly create great difficulties for tunnel waste to be used as concrete aggregate and greatly increase construction costs. Therefore, it is necessary to study the use of tunnel waste as concrete aggregate without secondary treatment, and to enable the prepared concrete to meet the requirements of on-site construction and mechanical properties, provided that the particle size is met. SUMMARY OF THE INVENTION

[0004] The invention provides concrete prepared by using tunnel waste slag and a preparation method thereof, and aims to solve the problem that directly using tunnel waste slag as concrete aggregate leads to poor construction and mechanical properties of concrete.

[0005] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention to solve the technical problem is: to provide a concrete prepared by using tunnel waste, comprising the following components by weight: 1800-2200 parts of tunnel waste, 300-450 parts of cement, 6-18 parts of polyaluminium ferric chloride, 2-10 parts of carboxymethyl cellulose, 6-18 parts of water reducing agent, and 135-225 parts of water.

[0006] Furthermore, the tunnel waste has a particle size of 0-63 mm, a crushing value index of ≤26%, and a mud content of 5-20%.

[0007] Furthermore, the cement is one of PO42.5 cement and PO42.5R cement.

[0008] Furthermore, the water reducing agent is a polycarboxylic acid-based high-performance water reducing agent.

[0009] Furthermore, the invention comprises the following components in parts by weight: 1850 parts of tunnel waste, 400 parts of cement, 8 parts of polyaluminium ferric chloride, 6 parts of carboxymethyl cellulose, 10 parts of water reducing agent and 180 parts of water.

[0010] The present invention also provides a method for preparing the concrete prepared by using the tunnel waste, comprising the following steps:

[0011] S1: First dissolve the water reducing agent into 1 / 3 of the concrete material water, dissolve the polyaluminium ferric chloride into 1 / 3 of the concrete material water, dissolve the carboxymethyl cellulose into 1 / 3 of the concrete material water, and let it stand for use.

[0012] S2: Pour the tunnel waste, the solution containing polyaluminium ferric chloride and the solution containing carboxymethyl cellulose into a blender and mix them for not less than 2 minutes.

[0013] S3: Add cement to the material after stirring in step S2 and continue stirring for no less than 2 minutes.

[0014] S4: After the stirring in step S3, a solution in which a water reducing agent is dissolved is added and the stirring is continued for 3-5 minutes to obtain concrete prepared by using the tunnel slag.

[0015] Furthermore, the tunnel waste is a type of tunnel waste obtained by TBM drilling and drilling and blasting, which is directly obtained on site without the need for secondary treatment such as crushing, shaping, washing and demuding.

[0016] Furthermore, the stirring speed of S2 is 40-60 rad / min.

[0017] Furthermore, the stirring speed of S3 is 40-60 rad / min.

[0018] Furthermore, the stirring speed of S4 is 40-60 rad / min.

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] 1. The present invention directly takes materials from the tunnel entrance or the waste dump, and directly uses the tunnel waste for preparing concrete, realizing that the tunnel waste completely replaces the natural concrete aggregate, and belongs to a green and environmentally friendly building material. The present invention reduces the stacking of a large amount of tunnel waste, reduces the safety hazards such as landslides and mud-rock flows caused by the stacking of waste, reduces the mining of a large amount of natural ores, alleviates the problem of lack of natural aggregates, and meets the requirements of building green projects.

[0021] 2. Compared with the traditional method of crushing, shaping, washing and demuding, etc., tunnel slag can only be used in concrete after secondary treatment. The present invention modifies the tunnel slag by adding admixture materials, which can reduce the impact of tunnel slag on concrete construction and mechanical properties, and can save a lot of construction costs.

[0022] 3. The polyaluminium ferric chloride and carboxymethyl cellulose provided by the present invention can reduce the harmful impurities in tunnel slag, especially the influence of soil particles in tunnel slag on the construction performance and mechanical properties of concrete by means of double electric layer compression, adsorption-electrical neutralization adsorption bridging, etc. Polyaluminium ferric chloride mainly promotes the formation of flocs by electrical neutralization, and carboxymethyl cellulose provides long chains for the flocculation and agglomeration of soil particles, and then forms flocs by bridging or bridging-neutralization. Polyaluminium ferric chloride and carboxymethyl cellulose can also neutralize the negative charge on the surface of soil particles, reduce electrostatic repulsion, cause soil particles to flocculate, increase free water content, thereby reducing the water-cement ratio of concrete and improving the construction and mechanical properties of concrete. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments. The illustrative embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0024] Unless otherwise defined, all professional terms used below have the same meaning as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0025] Example 1

[0026] A concrete prepared by using tunnel waste slag comprises the following components in parts by weight: 1850 parts of tunnel waste slag, 400 parts of cement, 8 parts of polyaluminium ferric chloride, 6 parts of carboxymethyl cellulose, 10 parts of high-performance water reducing agent, and 180 parts of water, and the proportion is shown in Table 1.

[0027] The above-mentioned method for preparing concrete using tunnel waste includes the following preparation process:

[0028] S1: First dissolve the water reducing agent into 1 / 3 of the concrete material water, dissolve the polyaluminium ferric chloride into 1 / 3 of the concrete material water, dissolve the carboxymethyl cellulose into 1 / 3 of the concrete material water, and let it stand for use.

[0029] S2: Pour the tunnel waste, the solution containing polyaluminium ferric chloride and the solution containing carboxymethyl cellulose into a mixer and mix and stir for not less than 2 minutes at a stirring speed of 40-60 rad / min.

[0030] S3: Add cement to the material after stirring in step S2 and continue stirring for no less than 2 minutes at a stirring speed of 40-60 rad / min.

[0031] S4: After the material is stirred in step S3, a solution containing a water reducing agent is added and the stirring is continued for 3-5 minutes to obtain concrete prepared using tunnel waste. The stirring speed is 40-60 rad / min.

[0032] Example 2

[0033] The difference between this embodiment and embodiment 1 is that the present embodiment contains 8 parts of carboxymethyl cellulose, and the rest is consistent with embodiment 1. The proportions are shown in Table 1.

[0034] Example 3

[0035] The difference between this embodiment and embodiment 1 is that in this embodiment, 12 parts of polyaluminium ferric chloride are used, and the rest are consistent with embodiment 1. The proportions are shown in Table 1.

[0036] Example 4

[0037] The difference between this embodiment and embodiment 1 is that in this embodiment, 16 parts of polyaluminium ferric chloride and 4 parts of carboxymethyl cellulose are used, and the rest are consistent with embodiment 1. The proportions are shown in Table 1.

[0038] Example 5

[0039] The difference between this embodiment and embodiment 1 is that in this embodiment, 16 parts of polyaluminium ferric chloride are used, and the rest are consistent with embodiment 1. The proportions are shown in Table 1.

[0040] Comparative Example 1

[0041] A concrete prepared by using tunnel waste includes the following components in parts by weight: 1850 parts of tunnel waste, 400 parts of cement, 10 parts of high-performance water reducing agent, and 180 parts of water. The proportion is shown in Table 1.

[0042] The above-mentioned method for preparing concrete using tunnel waste includes the following preparation process:

[0043] S1: First dissolve the water reducing agent into all the concrete materials and let it stand for later use.

[0044] S2: Pour the tunnel waste and cement into a mixer and mix for no less than 2 minutes at a mixing speed of 40-60 rad / min.

[0045] S3: After the stirring in step S2, a solution containing a water reducing agent is added to the material, and the stirring is continued for 3-5 minutes at a stirring speed of 40-60 rad / min to obtain concrete prepared by using the tunnel slag.

[0046] Table 1 Amount of each component of concrete prepared using tunnel slag (parts)

[0047]

[0048] Performance Testing

[0049] The construction performance and mechanical properties of the concrete prepared in Examples 1-5 and Comparative Example 1 were tested, and the results were as follows:

[0050] Table 2 Statistical table of performance test data of each group of concrete prepared using tunnel slag

[0051]

[0052] It can be seen from Table 2 that compared with Examples 1-5, Comparative Example 1 does not modify the tunnel waste, so that the free water adsorbed by the soil in the tunnel waste cannot be released, resulting in poor fluidity of the concrete. Examples 1-5 modify the tunnel waste by adding polyaluminum ferric chloride and carboxymethyl cellulose, so that the soil particles in the slag release the adsorbed free water, thereby increasing the fluidity of the concrete and increasing the water required for cement hydration. At the same time, polyaluminum ferric chloride and carboxymethyl cellulose can agglomerate the soil dispersed in the concrete material, reduce its influence on cement hydration, and thus improve the compressive strength of the concrete. The 3d cubic compressive strength of the concrete can be increased by 61.2-74.1%, and the 28d cubic compressive strength of the concrete can be increased by 48.6-62.3%.

[0053] Although the specific embodiments of the present invention describe the present invention in detail, it should not be understood as limiting the protection scope of this patent. Within the scope described in the claims, various modifications and variations that can be made by those skilled in the art without creative work still fall within the protection scope of this patent.

Claims

1. A method for preparing concrete using tunnel waste, characterized in that: The raw materials of the concrete include the following components in parts by weight: 1800-2200 parts of tunnel waste, 300-450 parts of cement, 6-18 parts of polyaluminium ferric chloride, 2-10 parts of carboxymethyl cellulose, 4-17 parts of water reducing agent, and 135-225 parts of water; The tunnel waste is a type of tunnel waste obtained by TBM drilling and drilling and blasting, and does not require crushing, shaping, or washing to remove mud; the tunnel waste has a particle size of 0-63 mm, a crushing value index of ≤26%, and a mud content of 5-20%; The concrete comprises the following preparation process: S1: Firstly, dissolve the water reducing agent into 1 / 3 of the water used for concrete materials, dissolve the polyaluminium ferric chloride into 1 / 3 of the water used for concrete materials, and dissolve the carboxymethyl cellulose into 1 / 3 of the water used for concrete materials, and let it stand for use; S2: Pour the tunnel waste, the solution containing polyaluminium ferric chloride and the solution containing carboxymethyl cellulose into a mixer and mix and stir for at least 2 minutes; S3: Add cement to the material after stirring in step S2 and continue stirring for no less than 2 minutes; S4: After the stirring in step S3, a solution in which a water reducing agent is dissolved is added and the stirring is continued for 3-5 minutes to obtain concrete prepared by using the tunnel slag.

2. The preparation method according to claim 1, characterized in that: The cement is one of PO42.5 cement and PO42.5R cement.

3. The preparation method according to claim 1, characterized in that: The water reducing agent is a polycarboxylic acid-based high-performance water reducing agent.

4. The preparation method according to claim 1, characterized in that: The invention comprises the following components in parts by weight: 1850 parts of tunnel waste, 400 parts of cement, 8 parts of polyaluminium ferric chloride, 6 parts of carboxymethyl cellulose, 10 parts of high-performance water reducing agent and 180 parts of water.

5. The preparation method according to claim 1, characterized in that: The stirring speed of S2 is 40-60 rad / min.

6. The preparation method according to claim 1, characterized in that: The stirring speed of S3 is 40-60 rad / min.

7. The preparation method according to claim 1, characterized in that: The stirring speed of S4 is 40-60 rad / min.

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