Road concrete as well as preparation method and application thereof

Abstract

The invention relates to the field of building materials, and provides road concrete as well as a preparation method and application thereof. The road surface layer concrete comprises 15-35 parts of a first cementing material, 35-60 parts of steel slag, 20-45 parts of sand, 8-15 parts of water, 1-2 parts of an auxiliary exciting agent and 0.1-0.3 part of a water reducing agent; the first cementing material comprises 20-50 parts of red mud, 0-10 parts of fly ash, 45-80 parts of slag powder, 0-10 parts of Portland cement clinker and 0-10 parts of gypsum; the road base concrete comprises 10-25 parts of a second cementing material, 40-55 parts of steel slag, 20-40 parts of sand, 3-7 parts of water, 1-3 parts of an auxiliary exciting agent and 0-0.3 part of a water reducing agent; the second cementing material comprises 20-50 parts of red mud, 0-10 parts of fly ash, 50-70 parts of slag powder and 0-10 parts of gypsum. The final road concrete has the advantages of low cost, low carbon, environmental protection and good wear resistance.

Description

Technical Field

[0001] The invention relates to the field of building materials, and in particular to road concrete and a preparation method and application thereof. Background Art

[0002] In the field of building materials, road concrete, as the main material for infrastructure construction, has always been the focus of industry attention for its performance and cost. Traditional road concrete mostly uses silicate cement as the main raw material of cementitious materials. The use of a large amount of silicate cement not only makes the production cost of road concrete very high, but also brings huge carbon emissions, which is not conducive to the green and sustainable development of the building materials industry. In addition, the accumulation of various industrial solid wastes also imposes a heavy burden on the environment. Furthermore, the existing road concrete also has the problem of poor wear resistance. In summary, it is of great significance to provide a low-cost, low-carbon, environmentally friendly, and highly wear-resistant road concrete. Summary of the invention

[0003] Therefore, the technical problem to be solved by the present invention is to overcome the defects of high cost, large carbon emissions, solid waste storage and poor wear resistance of road concrete in the prior art, thereby providing a road concrete and its preparation method and application.

[0004] To this end, the present invention provides the following technical solutions:

[0005] In a first aspect, the present invention provides a road concrete, including road surface layer concrete and road base layer concrete, wherein the road surface layer concrete includes the following raw materials in parts by weight:

[0006] 15-35 parts of the first cementitious material, 35-60 parts of steel slag, 20-45 parts of sand, 8-15 parts of water, 1-2 parts of the first auxiliary activator and 0.1-0.3 parts of the first water reducing agent;

[0007] The first gelling material comprises the following raw materials in parts by weight:

[0008] 20-50 parts of red mud, 0-10 parts of fly ash, 45-80 parts of slag powder, 0-10 parts of Portland cement clinker and 0-10 parts of gypsum;

[0009] The road base concrete comprises the following raw materials in parts by weight:

[0010] 10-25 parts of the second cementitious material, 40-55 parts of steel slag, 20-40 parts of sand, 3-7 parts of water, 1-3 parts of the second auxiliary activator and 0-0.3 parts of the second water reducing agent;

[0011] The second gelling material comprises the following raw materials in parts by weight:

[0012] 20-50 parts of red mud, 0-10 parts of fly ash, 50-70 parts of slag powder and 0-10 parts of gypsum.

[0013] Preferably, the road surface concrete comprises the following raw materials in parts by mass:

[0014] 18-35 parts of the first cementitious material, 38-60 parts of steel slag, 20-34 parts of sand, 8.5-15 parts of water, 1-1.8 parts of the first auxiliary activator and 0.1-0.3 parts of the first water reducing agent;

[0015] The first gelling material comprises the following raw materials in parts by weight:

[0016] 29-50 parts of red mud, 4-10 parts of fly ash, 49-80 parts of slag powder, 0-7 parts of Portland cement clinker and 0-6 parts of gypsum;

[0017] The road base concrete comprises the following raw materials in parts by weight:

[0018] 14-25 parts of the second cementitious material, 44-55 parts of steel slag, 20-37 parts of sand, 4-7 parts of water, 1.4-3 parts of the second auxiliary activator and 0-0.3 parts of the second water reducing agent;

[0019] The second gelling material comprises the following raw materials in parts by weight:

[0020] 25-50 parts of red mud, 4-10 parts of fly ash, 50-65 parts of slag powder and 4-10 parts of gypsum.

[0021] Further preferably, the road surface concrete comprises the following raw materials in parts by mass:

[0022] 20-22 parts of the first cementitious material, 41-43.5 parts of steel slag, 23-28 parts of sand, 9.4-10.4 parts of water, 1.5-1.6 parts of the first auxiliary activator and 0.1-0.2 parts of the first water reducing agent;

[0023] The first gelling material comprises the following raw materials in parts by weight:

[0024] 35-38 parts of red mud, 5-6 parts of fly ash, 50-54 parts of slag powder, 3-5 parts of Portland cement clinker and 4-5 parts of gypsum;

[0025] The road base concrete comprises the following raw materials in parts by weight:

[0026] 18-21 parts of the second cementitious material, 49-51 parts of steel slag, 28-37 parts of sand, 5.2-6.3 parts of water, 1.5-3 parts of the second auxiliary activator and 0.1-0.2 parts of the second water reducing agent;

[0027] The second gelling material comprises the following raw materials in parts by weight:

[0028] 30-35 parts of red mud, 6-10 parts of fly ash, 55-65 parts of slag powder and 5-6 parts of gypsum.

[0029] Preferably, the steel slag in the road surface concrete is a block waste slag produced by steelmaking, and its components include oxides of calcium, iron, silicon and magnesium; the particle size of the steel slag is 5 to 20 mm, and the gradation is continuous; the crushing value and water expansion rate of the steel slag comply with the relevant provisions of GB / T 25824-2010 "Steel Slag for Roads"; the crushing value of the steel slag is ≤30%, and the water expansion rate is ≤2.0%.

[0030] Preferably, the sand in the road surface concrete is machine-made sand; the particle size of the machine-made sand is 0.01-5 mm, and the fineness modulus is 2.3-3.0, which meets the requirements of JT / T 819-2023 "Machine-made Sand for Cement Concrete in Highway Engineering".

[0031] Preferably, the first auxiliary activator comprises one or more of sodium carbonate, sodium hydroxide and sodium silicate; the auxiliary activator is solid, and the water contained is mainly crystal water and chemically bound water / hydroxyl group; the solid content of the sodium carbonate, sodium hydroxide and sodium silicate is independently ≥95%; the modulus of the sodium silicate is 1.5 to 2.5.

[0032] Preferably, the first water reducer is a naphthalene-based high-efficiency water reducer.

[0033] Preferably, in the first cementitious material, the red mud is sintered red mud, which is solid waste discharged from the industrial production of alumina, and its components include oxides of calcium, iron, silicon, magnesium and aluminum; in the first cementitious material, the fly ash is Class C fly ash, which meets the requirements of GB / T 1596 "Fly ash used in cement and concrete", and has a moisture content of ≤1%; in the first cementitious material, the slag powder is water-quenched or air-cooled blast furnace slag powder; in the first cementitious material, the silicate cement clinker meets the requirements of GB / T21372 "Silica cement clinker", and has a moisture content of ≤1%.

[0034] Preferably, in the first cementitious material, the gypsum is industrial by-product gypsum, and the industrial by-product gypsum includes one or more of desulfurized gypsum, mirabilite gypsum, phosphogypsum and titanium gypsum; in addition to physically adsorbed water and free water (the total water content of the two parts is 8-12%), gypsum also contains crystalline water, but the amount of gypsum used in the raw materials is relatively small and does not need to be specially controlled.

[0035] Preferably, the above water content can be measured by a drying method.

[0036] Preferably, the steel slag in the road base concrete is a block waste slag produced by steelmaking, and its components include oxides of calcium, iron, silicon and magnesium; the particle size of the steel slag is 5 to 20 mm, and the gradation is continuous; the crushing value and water expansion rate of the steel slag comply with the relevant provisions of GB / T 25824-2010 "Steel Slag for Roads"; the crushing value of the steel slag is ≤30%, and the water expansion rate is ≤2.0%.

[0037] Preferably, the sand in the road base concrete is machine-made sand; the particle size of the machine-made sand is 0.01-5 mm, and the fineness modulus is 2.3-3.0, which meets the requirements of JT / T 819-2023 "Machine-made Sand for Cement Concrete in Highway Engineering".

[0038] Preferably, the second auxiliary activator comprises one or more of sodium carbonate, sodium hydroxide and sodium silicate; the auxiliary activator is solid, and the water contained is mainly crystal water and chemically bound water / hydroxyl group; the solid content of the sodium carbonate, sodium hydroxide and sodium silicate is independently ≥95%; the modulus of the sodium silicate is 1.5 to 2.5.

[0039] Preferably, the second water reducer is a naphthalene-based high-efficiency water reducer.

[0040] Preferably, the requirements for red mud, fly ash, slag powder and gypsum in the second cementitious material are the same as those of the first cementitious material.

[0041] In another aspect, the present invention provides a method for preparing road concrete, comprising the following steps: preparing road surface concrete and road base concrete respectively;

[0042] The method for preparing the road surface concrete comprises: mixing the raw materials of the road surface concrete;

[0043] The method for preparing road base concrete comprises: mixing the raw materials of the road base concrete.

[0044] In an optional embodiment, in the method for preparing road surface concrete, a pretreatment step is also included before the raw materials are mixed.

[0045] Optionally, the pretreatment includes grinding and drying the red mud and slag powder respectively.

[0046] Optionally, the pretreatment includes drying the steel slag.

[0047] Optionally, the moisture content during the grinding process is ≤3%, and the particle size of the red mud and slag powder obtained by grinding satisfies the 80μm square hole sieve residue of ≤10%; after drying, the moisture content of the red mud, slag powder and steel slag is independently ≤1%, and the moisture content refers to the sum of physically adsorbed water and free water, excluding chemically bound water and crystallized water.

[0048] In an optional embodiment, in the method for preparing road surface concrete, a molding step is further included after the raw materials are mixed.

[0049] Optionally, the molding step includes: mixing the raw materials and then vibrating and molding them.

[0050] Optionally, the vibration molding time is 30 to 60 seconds, and the vibration is 30 to 60 seconds to eliminate bubbles and ensure compactness.

[0051] In an optional embodiment, in the preparation method of road surface concrete, the step of mixing the raw materials of the road surface concrete includes: mixing red mud, slag powder, fly ash, silicate cement clinker and gypsum to obtain a first cementitious material; mixing the first cementitious material and a first auxiliary stimulator to obtain a first mixture; mixing the first mixture with steel slag and sand to obtain a second mixture; adding water and a first water reducer to the second mixture and stirring evenly.

[0052] In an optional embodiment, in the method for preparing road base concrete, a pretreatment step is also included before the raw materials are mixed.

[0053] Optionally, the pretreatment includes grinding and drying the red mud and slag powder respectively.

[0054] Optionally, the pretreatment includes drying the steel slag.

[0055] Optionally, the moisture content during the grinding process is ≤3%, and the particle size of the red mud and slag powder obtained by grinding satisfies the 80μm square hole sieve residue of ≤10%; after drying, the moisture content of the red mud, slag powder and steel slag is independently ≤1%, and the moisture content refers to the sum of physically adsorbed water and free water, excluding chemically bound water and crystallized water.

[0056] In an optional embodiment, in the method for preparing road base concrete, a pressing step is further included after the raw materials are mixed.

[0057] Optionally, the pressing pressure is 8 to 12 MPa and the pressing time is 55 to 65 s.

[0058] In an optional embodiment, in the preparation method of road base concrete, the step of mixing the raw materials of the road base concrete includes: mixing red mud, slag powder, fly ash and gypsum to obtain a second cementitious material; mixing the second cementitious material and a second auxiliary stimulator to obtain a third mixture; mixing the third mixture with steel slag and sand to obtain a fourth mixture; adding water and a second water reducer to the fourth mixture and stirring evenly.

[0059] In another aspect, the present invention provides a road concrete or a use of the road concrete prepared according to the preparation method in a road.

[0060] Preferably, the method of application comprises the following steps:

[0061] The raw materials of the road base concrete are mixed and laid on the road surface, and then pressed and subjected to the first curing in sequence to complete the laying of the road base concrete; then, the raw materials of the road surface layer concrete are mixed and laid on the road base concrete surface, and then vibrated and formed and subjected to the second curing in sequence to complete the laying of the road surface layer concrete.

[0062] Preferably, the pressing is performed using a road roller or compacting equipment to ensure the compactness and flatness of the road base concrete.

[0063] Preferably, the humidity of the first curing is 94-96% and the temperature is 19-21°C.

[0064] Preferably, the vibration compaction is carried out by vibrating and compacting with a concrete vibrator to ensure the density and flatness of the road surface concrete.

[0065] Preferably, the humidity of the second curing is 94-96% and the temperature is 19-21°C.

[0066] The technical solution of the present invention has the following advantages:

[0067] 1. The present invention provides a road concrete, comprising a road surface concrete and a road base concrete, wherein the road surface concrete comprises the following raw materials in parts by weight: 15-35 parts of a first cementitious material, 35-60 parts of steel slag, 20-45 parts of sand, 8-15 parts of water, 1-2 parts of a first auxiliary activator and 0.1-0.3 parts of a first water reducing agent; the first cementitious material comprises the following raw materials in parts by weight: 20-50 parts of red mud, 0-10 parts of fly ash, 45-60 parts of slag powder, 0.1-0.3 parts of a first auxiliary activator and 0.1-0.3 parts of a first water reducing agent. 80 parts, silicate cement clinker 0-10 parts and gypsum 0-10 parts; the road base concrete includes the following raw materials in parts by weight: 10-25 parts of a second cementitious material, 40-55 parts of steel slag, 20-40 parts of sand, 3-7 parts of water, 1-3 parts of a second auxiliary activator and 0-0.3 parts of a second water reducing agent; the second cementitious material includes the following raw materials in parts by weight: 20-50 parts of red mud, 0-10 parts of fly ash, 50-70 parts of slag powder and 0-10 parts of gypsum. The amount of solid waste (including red mud, fly ash, gypsum, and slag powder) in the cementitious material of the road surface concrete of the present invention can reach 90%, and the amount of solid waste in the cementitious material of the road base concrete can reach 100%. The road concrete prepared by the present invention utilizes a large amount of various solid wastes, solves the problem of solid waste storage, and has a significant environmental protection effect; the road concrete has the advantages of low energy consumption (greatly reducing the energy consumption in the high-temperature calcination process of silicate cement clinker), low cost, and low carbon.

[0068] The road concrete prepared by the present invention exhibits good mechanical properties in both the early and late stages, and has excellent wear resistance, thus broadening the application field. Specifically, the slag powder, red mud, and fly ash in the cementitious material of the present invention react with the auxiliary activator to form a dense hydration product, which reduces the porosity of the concrete, thereby improving the mechanical strength and wear resistance of the concrete. The present invention optimizes the ratio design by matching the raw materials in reasonable proportions, making the concrete denser, reducing microcracks and pores, and improving wear resistance.

[0069] 2. The particle size of steel slag is 5-20mm, the crushing value is ≤30%, and the water expansion rate is ≤2.0%; the high hardness and low crushing value of steel slag particles provide better aggregate support effect, which helps to enhance the compression and wear resistance of concrete under external loads.

[0070] 3. The present invention provides a method for preparing road concrete, comprising the following steps: preparing road surface concrete and road base concrete respectively; the method for preparing road surface concrete comprises: mixing the raw materials of the road surface concrete; the method for preparing road base concrete comprises: mixing the raw materials of the road base concrete. The preparation method of the present invention is simple, with low consumption and low CO2 emission during the preparation process; it hardens quickly, has high strength and a wide range of applications; it is easy to prepare, has low cost, is energy-saving, and is low-carbon and environmentally friendly; from the perspectives of technology, economy and environmental protection, the present invention will have significant social, economic and environmental benefits, is highly practical, and is suitable for popularization and use. DETAILED DESCRIPTION

[0071] The following examples are provided for a better understanding of the present invention, but are not intended to limit the best mode of implementation, nor to limit the content and protection scope of the present invention. Any product identical or similar to the present invention obtained by anyone under the inspiration of the present invention or by combining the features of the present invention with other prior arts shall fall within the protection scope of the present invention.

[0072] If no specific experimental steps or conditions are specified in the examples, the conventional experimental steps or conditions described in the literature in the field can be used. If no manufacturer is specified for the reagents or instruments used, they are all conventional reagent products that can be obtained commercially.

[0073] Unless otherwise specified, the raw materials used in the embodiments of the present invention are all well-known, commercially available chemical raw materials, specifically:

[0074] Steel slag is a blocky waste slag produced by steelmaking, and its components include oxides of calcium, iron, silicon and magnesium; the particle size of steel slag is 5 to 20 mm, with continuous grading; the crushing value and water expansion rate meet the relevant provisions of GB / T25824-2010 "Steel Slag for Road Use", with a crushing value of ≤30% and a water expansion rate of ≤2.0%;

[0075] The sand is machine-made sand with a particle size of 0.01-5 mm and a fineness modulus of 2.3-3.0, which meets the requirements of JT / T 819-2023 "Machine-made sand for cement concrete in highway engineering";

[0076] The solid content of the auxiliary activator is ≥95%, and the modulus of sodium silicate is 2;

[0077] The water reducer is a naphthalene-based high-efficiency water reducer;

[0078] Red mud is sintered red mud, which is solid waste discharged from the industrial production of alumina. Its components include oxides of calcium, iron, silicon, magnesium and aluminum.

[0079] The fly ash is Class C fly ash, which meets the requirements of GB / T 1596 "Fly ash used in cement and concrete", and has a moisture content of ≤1%;

[0080] The slag powder is water-quenched or air-cooled blast furnace slag powder;

[0081] Portland cement clinker shall comply with the requirements of GB / T 21372 "Portland cement clinker", with a moisture content of ≤1%;

[0082] Gypsum is an industrial by-product of gypsum. The total water content of the two parts of physically adsorbed water and free water in gypsum is 8-12%.

[0083] Example 1

[0084] This embodiment provides a road concrete, including road surface concrete and road base concrete.

[0085] The road surface concrete includes the following raw materials in parts by weight: 18 parts of cementitious materials, 38 parts of steel slag, 34 parts of sand, 8.5 parts of water, 1.8 parts of auxiliary activator, and 0.1 parts of water reducing agent. Among them, the cementitious materials include the following raw materials in parts by weight: 29 parts of red mud, 4 parts of fly ash, 54 parts of slag powder, 7 parts of silicate cement clinker, and 6 parts of gypsum; the auxiliary activator is sodium carbonate, and the gypsum is desulfurized gypsum.

[0086] The mix ratio of the road surface concrete in this embodiment is as follows: cementitious material 414kg / m 3 、Steel slag 874kg / m 3 、Sand 782kg / m 3 、Water 195.5kg / m 3 、Auxiliary stimulant 41.4kg / m 3 , water reducing agent 2.3kg / m 3 .

[0087] The road base concrete includes the following raw materials in parts by weight: 14 parts of cementitious materials, 44 parts of steel slag, 37 parts of sand, 4 parts of water, 1.4 parts of auxiliary activator, and 0 parts of water reducing agent. Among them, the cementitious materials include the following raw materials in parts by weight: 25 parts of red mud, 4 parts of fly ash, 65 parts of slag powder, and 6 parts of gypsum; the auxiliary activator is sodium carbonate, and the gypsum is desulfurized gypsum.

[0088] The mix ratio of the road base concrete in this embodiment is as follows: cementitious material 308kg / m 3 、Steel slag 968kg / m 3 、Sand 814kg / m 3 、Water 88kg / m 3 、Auxiliary stimulant 30.8kg / m 3 , water reducing agent 0kg / m 3 .

[0089] The preparation method of road base concrete comprises:

[0090] (1) Pretreatment: Grinding and drying red mud and slag powder in turn (the water content during grinding is ≤3%, and the particle size of each sample powder obtained by grinding satisfies the 80 μm square hole sieve residue of ≤10%; after drying, the water content of red mud is ≤1%, and the water content of slag powder is ≤1%); drying steel slag (after drying, the water content of steel slag is ≤1%);

[0091] (2) Mixing: mixing the pretreated red mud, the pretreated slag powder, fly ash and gypsum to obtain a cementitious material; mixing the cementitious material and an auxiliary activator to obtain a third mixture; mixing the third mixture with the pretreated steel slag and sand to obtain a fourth mixture; adding water and a water reducing agent to the fourth mixture and stirring evenly;

[0092] (3) Pressing: Press the material obtained by stirring evenly, set the pressing pressure to 10 MPa, and the pressing time to 60 s to obtain a cylindrical sample with a diameter of 50 mm and a height of 50 mm, which is the road base concrete to be tested.

[0093] The preparation method of road surface concrete comprises:

[0094] (1) Pretreatment: Grinding and drying red mud and slag powder in turn (the water content during grinding is ≤3%, and the particle size of each sample powder obtained by grinding satisfies the 80 μm square hole sieve residue of ≤10%; after drying, the water content of red mud is ≤1%, and the water content of slag powder is ≤1%); drying steel slag (after drying, the water content of steel slag is ≤1%);

[0095] (2) Mixing: mixing the pretreated red mud, the pretreated slag powder, fly ash, silicate cement clinker and gypsum to obtain a cementitious material; mixing the cementitious material and an auxiliary activator to obtain a first mixture; mixing the first mixture with the pretreated steel slag and sand to obtain a second mixture; adding water and a water reducing agent to the second mixture and stirring evenly;

[0096] (3) Molding: The mixed material is placed into a cubic steel mold with a size of 150 mm × 150 mm × 150 mm and a rectangular steel mold with a size of 50 mm × 200 mm × 200 mm, and placed on a vibration table together with the mold for molding. The vibration time is set to 60 s to obtain the road surface concrete for testing.

[0097] Example 2

[0098] This embodiment provides a road concrete, including road surface concrete and road base concrete.

[0099] The road surface concrete includes the following raw materials in parts by weight: 20 parts of cementitious materials, 41 parts of steel slag, 28 parts of sand, 9.4 parts of water, 1.5 parts of auxiliary activator, and 0.2 parts of water reducing agent. Among them, the cementitious materials include the following raw materials in parts by weight: 35 parts of red mud, 5 parts of fly ash, 50 parts of slag powder, 5 parts of silicate cement clinker, and 5 parts of gypsum; the auxiliary activator includes 1 part of sodium carbonate and 0.5 parts of sodium silicate, and the gypsum is titanium gypsum.

[0100] The mix ratio of the road surface concrete in this embodiment is as follows: cementitious material 460kg / m 3 、Steel slag 943kg / m 3 、Sand 644kg / m 3 , water 216.2kg / m 3 、Auxiliary stimulant 34.5kg / m 3 , water reducing agent 4.6kg / m 3 .

[0101] The road base concrete includes the following raw materials in parts by weight: 18 parts of cementitious materials, 49 parts of steel slag, 28 parts of sand, 5.2 parts of water, 1.5 parts of auxiliary activator, and 0.1 parts of water reducing agent. Among them, the cementitious materials include the following raw materials in parts by weight: 35 parts of red mud, 6 parts of fly ash, 55 parts of slag powder, and 4 parts of gypsum; the auxiliary activator includes 1 part of sodium carbonate and 0.5 parts of sodium hydroxide, and the gypsum is mirabilite gypsum.

[0102] The mix ratio of the road base concrete in this embodiment is as follows: 396 kg / m 3 、Steel slag 1078kg / m 3 , sand 616kg / m 3 , water 114.4kg / m3 、Auxiliary stimulant 33kg / m 3 , water reducing agent 2.2kg / m 3 .

[0103] The preparation method of the road base concrete and the preparation method of the road surface concrete are the same as those in Example 1.

[0104] Example 3

[0105] This embodiment provides a road concrete, including road surface concrete and road base concrete.

[0106] The road surface concrete includes the following raw materials in parts by weight: 22 parts of cementitious materials, 43.5 parts of steel slag, 23 parts of sand, 10.4 parts of water, 1.6 parts of auxiliary activator, and 0.2 parts of water reducing agent. Among them, the cementitious materials include the following raw materials in parts by weight: 38 parts of red mud, 6 parts of fly ash, 49 parts of slag powder, 3 parts of silicate cement clinker, and 4 parts of gypsum; the auxiliary activator includes 0.8 parts of sodium carbonate, 0.4 parts of sodium hydroxide, and 0.4 parts of sodium silicate, and the gypsum is phosphogypsum.

[0107] The mix ratio of the road surface concrete in this embodiment is as follows: cementitious material 506kg / m 3 、Steel slag 1000.5kg / m 3 、Sand 529kg / m 3 , water 239.2kg / m 3 、Auxiliary stimulant 36.8kg / m 3 , water reducing agent 4.6kg / m 3 .

[0108] The road base concrete includes the following raw materials in parts by weight: 21 parts of cementitious materials, 51 parts of steel slag, 20 parts of sand, 6.3 parts of water, 1.5 parts of auxiliary activator, and 0.2 parts of water reducing agent. Among them, the cementitious materials include the following raw materials in parts by weight: 30 parts of red mud, 10 parts of fly ash, 55 parts of slag powder, and 5 parts of gypsum; the auxiliary activator includes 0.5 parts of sodium carbonate, 0.5 parts of sodium hydroxide, and 0.5 parts of sodium silicate), and the gypsum is phosphogypsum.

[0109] The mix ratio of the road base concrete in this embodiment is as follows: 462kg / m 3 、Steel slag 1122kg / m 3 , sand 440kg / m 3 、Water 138.6kg / m 3 、Auxiliary stimulant 33kg / m 3 , water reducing agent 4.4kg / m 3 .

[0110] The preparation method of the road base concrete and the preparation method of the road surface concrete are the same as those in Example 1.

[0111] Comparative Example 1

[0112] This comparative example provides a road base concrete, in which other raw materials in the road base concrete of Example 1 are kept unchanged, the addition of the auxiliary activator is omitted, and the composition of the cementitious material is modified to include the following raw materials in parts by weight: 94 parts of 42.5 grade ordinary Portland cement and 6 parts of gypsum.

[0113] The mix ratio of the road base concrete in this comparative example is as follows: cementitious material 308kg / m 3 、Steel slag 968kg / m 3 、Sand 814kg / m 3 、Water 88kg / m 3 、Auxiliary stimulant 0kg / m 3 , water reducing agent 0kg / m 3 .

[0114] Preparation method:

[0115] (1) Pretreatment: drying the steel slag (after drying, the moisture content of the steel slag is ≤1%);

[0116] (2) Mixing: mixing gypsum and 42.5 grade ordinary Portland cement to obtain a cementitious material; mixing the cementitious material, the pretreated steel slag and sand to obtain a first mixture; adding water and a water reducing agent to the first mixture and stirring uniformly;

[0117] (3) Pressing: Press the material obtained by stirring evenly, set the pressing pressure to 10 MPa, and the pressing time to 60 s to obtain a cylindrical sample with a diameter of 50 mm and a height of 50 mm, which is the road base concrete to be tested.

[0118] Comparative Example 2

[0119] This comparative example provides a road base concrete, in which other raw materials in the road base concrete of Example 1 remain unchanged, and steel slag is replaced by crushed stone.

[0120] The mix ratio of the road base concrete in this comparative example is as follows: cementitious material 308kg / m 3 、Crushed stone 968kg / m 3 、Sand 814kg / m 3 、Water 88kg / m 3 、Auxiliary stimulant 30.8kg / m 3 , water reducing agent 0kg / m 3 .

[0121] Preparation method:

[0122] (1) Pretreatment: Grinding and drying the red mud and slag powder respectively (the water content during the grinding process is ≤3%, and the particle size of each sample powder obtained by grinding satisfies the 80 μm square hole sieve residue of ≤10%; after the drying treatment, the water content of the red mud is ≤1%, and the water content of the slag powder is ≤1%);

[0123] (2) Mixing: mixing the pretreated red mud, the pretreated slag powder, fly ash and gypsum to obtain a cementitious material; mixing the cementitious material and an auxiliary activator to obtain a first mixture; mixing the first mixture with crushed stone and sand to obtain a second mixture; adding water and a water reducing agent to the second mixture and stirring evenly;

[0124] (3) Pressing: Press the material obtained by stirring evenly, set the pressing pressure to 10 MPa, and the pressing time to 60 s to obtain a cylindrical sample with a diameter of 50 mm and a height of 50 mm, which is the road base concrete to be tested.

[0125] Comparative Example 3

[0126] This comparative example provides a road surface concrete, in which other raw materials in the road surface concrete of Example 1 remain unchanged, and steel slag is replaced by crushed stone.

[0127] The mix ratio of the road surface concrete in this comparative example is as follows: cementitious material 414kg / m 3 、Crushed stone 874kg / m 3 、Sand 782kg / m 3 、Water 195.5kg / m 3 、Auxiliary stimulant 41.4kg / m 3 , water reducing agent 2.3kg / m 3 .

[0128] Preparation method:

[0129] (1) Pretreatment: Grinding and drying the red mud and slag powder respectively (the water content during the grinding process is ≤3%, and the particle size of each sample powder obtained by grinding satisfies the 80 μm square hole sieve residue of ≤10%; after the drying treatment, the water content of the red mud is ≤1%, and the water content of the slag powder is ≤1%);

[0130] (2) Mixing: mixing the pretreated red mud, the pretreated slag powder, fly ash, silicate cement clinker and gypsum to obtain a cementitious material; mixing the cementitious material and an auxiliary activator to obtain a first mixture; mixing the first mixture with crushed stone and sand to obtain a second mixture; adding water and a water reducing agent to the second mixture and stirring evenly;

[0131] (3) Molding: The mixed material is placed into a cubic steel mold with a size of 150 mm × 150 mm × 150 mm and a rectangular steel mold with a size of 50 mm × 200 mm × 200 mm, and placed on a vibration table together with the mold for molding. The vibration time is set to 60 s to obtain the road surface concrete for testing.

[0132] Comparative Example 4

[0133] This comparative example provides a road surface concrete, in which other raw materials in the road surface concrete of Example 1 remain unchanged, the addition of the auxiliary activator is omitted, and the composition of the cementitious material is modified to include the following raw materials in parts by weight: 87 parts of 42.5 grade ordinary Portland cement, 7 parts of Portland cement clinker, and 6 parts of gypsum.

[0134] The mix ratio of the road surface concrete in this comparative example is as follows: cementitious material 414kg / m 3 、Steel slag 874kg / m 3 、Sand 782kg / m 3 、Water 195.5kg / m 3 、Auxiliary stimulant 0kg / m 3 , water reducing agent 2.3kg / m 3 .

[0135] Preparation method:

[0136] (1) Pretreatment: drying the steel slag (after drying, the moisture content of the steel slag is ≤1%);

[0137] (2) Mixing: ordinary Portland cement, Portland cement clinker and gypsum are mixed to obtain a cementitious material; the cementitious material is mixed with the pre-treated steel slag and sand to obtain a first mixture; water and a water reducing agent are added to the first mixture and stirred evenly;

[0138] (3) Molding: The mixed material is placed into a cubic steel mold with a size of 150 mm × 150 mm × 150 mm and a rectangular steel mold with a size of 50 mm × 200 mm × 200 mm, and placed on a vibration table together with the mold for molding. The vibration time is set to 60 s to obtain the road surface concrete for testing.

[0139] The road base concrete prepared in Examples 1 to 3 and Comparative Examples 1 to 2 were sealed with plastic wrap to prevent moisture from entering, and were cured in a constant temperature and humidity environment with a temperature of 20±1°C and a humidity of 95±1% until the day before each age; then, the test blocks of each age were soaked in water for 24 hours one day in advance, and then the unconfined compressive strength was tested using an automatic compression testing machine in accordance with the test regulations for inorganic binder stabilized materials for highway engineering JTGE51-2009. Among them, 3 parallel specimens were prepared for each group of specimens, and the arithmetic mean was taken as the strength data to obtain the strength test results of different road base concretes, as shown in Table 1.

[0140] Table 1 Strength test results of different road base concrete

[0141] serial number 7d compressive strength / MPa 28d compressive strength / MPa Example 1 14.8 24.9 Example 2 15.2 25.6 Example 3 14.5 25.2 Comparative Example 1 12.7 20.8 Comparative Example 2 12.6 20.6

[0142] The road surface concrete prepared in Examples 1 to 3 and Comparative Examples 3 to 4, together with the mold, was placed in a constant temperature and humidity environment with a temperature of 20±1°C and a humidity of 95±1% for curing for 24 hours; after the curing was completed, the mold and test block were taken out of the standard curing box, the mold was removed, and the test block was continued to be placed in the standard curing box for curing to each age; the test block was taken out, the 150mm×150mm×150mm test block was subjected to strength test by an unconfined compressive strength press, and the 50mm×200mm×200mm test block was subjected to strength test by a bending tensile strength tester, and the strength data was recorded (compressive strength and bending tensile strength tests were based on the highway engineering cement and cement concrete test procedures). Three parallel specimens were prepared for each group of samples, and their arithmetic mean was taken as the strength data. In addition, the specimens cured to the age were dried, and then the specimens were placed on the horizontal turntable of the wear resistance testing machine, followed by pre-grinding for 30 turns under a load of 300N, and the specimens were taken out to weigh the mass. Then put the test block back to the original position of the horizontal turntable, grind it for another 40 turns and take it down to weigh the mass. Finally, according to the cement concrete wear resistance test method in JTGE30-2005 "Testing Procedures for Cement and Cement Concrete in Highway Engineering", the wear resistance test of each road surface concrete was carried out and the data was recorded. The performance test results of different road surface concretes are shown in Table 2.

[0143] Table 2 Performance test results of different road surface concrete

[0144]

[0145]

[0146] In the road concrete prepared by the present invention, the cementitious material of the road base concrete avoids the use of silicate cement clinker, and the amount of solid waste used can reach 100%. While fully realizing low carbon, low cost, low energy consumption and environmental protection, it can also meet the requirements for the base in road concrete and have suitable compressive strength; in addition, the present invention adjusts the raw materials contained in the road surface layer concrete so that the obtained road surface layer concrete has excellent compressive and tensile strength and wear resistance, thereby realizing the requirement for high wear resistance of the surface layer in the road concrete, and at the same time, the amount of solid waste used in the cementitious material of the road surface layer concrete can also reach 90%.

[0147] In summary, the special composition of the road base concrete and the road surface concrete of the present invention enables the road to be environmentally friendly, low-carbon, low-cost, and low-energy-consuming while having good compressive and tensile strength, and the wear resistance is greatly improved.

[0148] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A road concrete, comprising a road surface concrete and a road base concrete, characterized in that: The road surface concrete comprises the following raw materials in parts by mass: 15-35 parts of the first cementitious material, 35-60 parts of steel slag, 20-45 parts of sand, 8-15 parts of water, 1-2 parts of the first auxiliary activator and 0.1-0.3 parts of the first water reducing agent; The first gelling material comprises the following raw materials in parts by weight: 20-50 parts of red mud, 0-10 parts of fly ash, 45-80 parts of slag powder, 0-10 parts of Portland cement clinker and 0-10 parts of gypsum; The road base concrete comprises the following raw materials in parts by weight: 10-25 parts of the second cementitious material, 40-55 parts of steel slag, 20-40 parts of sand, 3-7 parts of water, 1-3 parts of the second auxiliary activator and 0-0.3 parts of the second water reducing agent; The second gelling material comprises the following raw materials in parts by weight: 20-50 parts of red mud, 0-10 parts of fly ash, 50-70 parts of slag powder and 0-10 parts of gypsum.

2. The road concrete according to claim 1, characterized in that: The road surface concrete comprises the following raw materials in parts by mass: 18-35 parts of the first cementitious material, 38-60 parts of steel slag, 20-34 parts of sand, 8.5-15 parts of water, 1-1.8 parts of the first auxiliary activator and 0.1-0.3 parts of the first water reducing agent; The first gelling material comprises the following raw materials in parts by weight: 29-50 parts of red mud, 4-10 parts of fly ash, 49-80 parts of slag powder, 0-7 parts of Portland cement clinker and 0-6 parts of gypsum; and / or The road base concrete comprises the following raw materials in parts by weight: 14-25 parts of the second cementitious material, 44-55 parts of steel slag, 20-37 parts of sand, 4-7 parts of water, 1.4-3 parts of the second auxiliary activator and 0-0.3 parts of the second water reducing agent; The second gelling material comprises the following raw materials in parts by weight: 25-50 parts of red mud, 4-10 parts of fly ash, 50-65 parts of slag powder and 4-10 parts of gypsum.

3. The road concrete according to claim 1 or 2, characterized in that: The road surface concrete comprises the following raw materials in parts by mass: 20-22 parts of the first cementitious material, 41-43.5 parts of steel slag, 23-28 parts of sand, 9.4-10.4 parts of water, 1.5-1.6 parts of the first auxiliary activator and 0.1-0.2 parts of the first water reducing agent; The first gelling material comprises the following raw materials in parts by weight: 35-38 parts of red mud, 5-6 parts of fly ash, 50-54 parts of slag powder, 3-5 parts of Portland cement clinker and 4-5 parts of gypsum; and / or The road base concrete comprises the following raw materials in parts by weight: 18-21 parts of the second cementitious material, 49-51 parts of steel slag, 28-37 parts of sand, 5.2-6.3 parts of water, 1.5-3 parts of the second auxiliary activator and 0.1-0.2 parts of the second water reducing agent; The second gelling material comprises the following raw materials in parts by weight: 30-35 parts of red mud, 6-10 parts of fly ash, 55-65 parts of slag powder and 5-6 parts of gypsum.

4. The road concrete according to claim 1, characterized in that: The particle size of the steel slag in the road surface concrete is 5 to 20 mm, the crushing value is ≤30%, and the water expansion rate is ≤2.0%; Preferably, the sand in the road surface concrete is machine-made sand; the particle size of the machine-made sand is 0.01 to 5 mm, and the fineness modulus is 2.3 to 3.0; Preferably, the first auxiliary activator includes one or more of sodium carbonate, sodium hydroxide and sodium silicate; the modulus of the sodium silicate is 1.5 to 2.

5.

5. The road concrete according to claim 1, characterized in that: The particle size of the steel slag in the road base concrete is 5 to 20 mm, the crushing value is ≤30%, and the water expansion rate is ≤2.0%; Preferably, the sand in the road base concrete is machine-made sand; the particle size of the machine-made sand is 0.01 to 5 mm, and the fineness modulus is 2.3 to 3.0; Preferably, the second auxiliary activator includes one or more of sodium carbonate, sodium hydroxide and sodium silicate; the modulus of the sodium silicate is 1.5 to 2.

5.

6. The method for preparing road concrete according to any one of claims 1 to 5, characterized in that: The method comprises the following steps: preparing a road surface concrete and a road base concrete respectively; The method for preparing the road surface concrete comprises: mixing the raw materials of the road surface concrete; The method for preparing road base concrete comprises: mixing the raw materials of the road base concrete.

7. The method for preparing road concrete according to claim 6, characterized in that: The method for preparing the road surface concrete satisfies at least one of the following conditions: (1) The raw materials also include a pretreatment step before mixing; Optionally, the pretreatment includes grinding and drying the red mud and slag powder in sequence; Optionally, the pretreatment includes drying the steel slag; (2) After the raw materials are mixed, a molding step is also included; Optionally, the molding step includes: mixing the raw materials and then vibrating and molding them; Optionally, the vibration molding time is 30 to 60 seconds; (3) The step of mixing the raw materials of the road surface concrete includes: mixing red mud, slag powder, fly ash, silicate cement clinker and gypsum to obtain a first cementitious material; mixing the first cementitious material and a first auxiliary activator to obtain a first mixture; mixing the first mixture with steel slag and sand to obtain a second mixture; adding water and a first water reducing agent to the second mixture and stirring evenly.

8. The method for preparing road concrete according to claim 6, characterized in that: The method for preparing road base concrete meets at least one of the following conditions: (1) The raw materials also include a pretreatment step before mixing; Optionally, the pretreatment includes grinding and drying the red mud and slag powder in sequence; Optionally, the pretreatment includes drying the steel slag; (2) After the raw materials are mixed, a pressing step is also included; Optionally, the pressing pressure is 8-12 MPa and the pressing time is 55-65 s; (3) the step of mixing the raw materials of the road base concrete comprises: mixing red mud, slag powder, fly ash and gypsum to obtain a second cementitious material; The second cementitious material and the second auxiliary stimulator are mixed to obtain a third mixture; the third mixture is mixed with steel slag and sand to obtain a fourth mixture; water and the second water reducing agent are added to the fourth mixture and stirred evenly.

9. Use of the road concrete according to any one of claims 1 to 5 or the road concrete prepared by the preparation method according to any one of claims 6 to 8 in roads.

10. The use according to claim 9, characterized in that: The method of the application comprises the following steps: The raw materials of the road base concrete are mixed and laid on the road surface, and then pressed and subjected to the first curing in sequence to complete the laying of the road base concrete; then, the raw materials of the road surface layer concrete are mixed and laid on the road base concrete surface, and then vibrated and formed and subjected to the second curing in sequence to complete the laying of the road surface layer concrete.

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