Early-strength non-clinker concrete prepared by using ammonia-alkali white mud and preparation method thereof

Abstract

The present application relates to a kind of early-strength type no clinker concrete prepared with ammonia-alkali white mud and its preparation method, the present application includes by mass fraction: ammonia-alkali white mud 65~235 parts, slag powder 140~245 parts, steel slag powder 35~105 parts, industrial byproduct gypsum 30~60 parts, fine aggregate 770~895 parts, coarse aggregate 1040~1070 parts, polycarboxylic acid water reducing agent 5~9 parts, mixing water 120~166 parts.The present application does not need to dry, after being broken into fine particles or being made into slurry, it can be used for preparing concrete, without mixing industrial product as activator, further reduce cost, no clinker concrete 1d compressive strength ≥6.0MPa, 3d compressive strength ≥20.0MPa, 28d compressive strength ≥35.0MPa.

Description

Technical Field

[0001] The present invention relates to the technical field of concrete preparation, in particular to an early-strength clinker-free concrete prepared by utilizing ammonia-alkali white mud and a preparation method thereof. Background Art

[0002] Ammonia-soda mud (also known as "alkali slag") is a white precipitate waste discharged during the ammonia distillation process of producing soda ash using the ammonia-soda process. Its main components are CaCO3, CaCl2, Ca(OH)2, and CaSO4. The production of one ton of soda ash produces 0.3 to 0.6 tons of dry ammonia-soda mud. The particle size of this mud generally ranges from 2μm to 50μm. After air-drying, it easily produces dust that can be inhaled, posing a health hazard. Ammonia-soda mud is highly absorbent and has a high water content. The pH of its leachate is approximately 10 to 12, making it highly alkaline. Long-term storage will cause serious pollution to the soil and groundwater. Currently, my country has a huge stockpile of ammonia-soda mud, but its comprehensive utilization rate is low. Large amounts of this mud are stored in open-air dumps or landfilled on site, severely impacting the health of surrounding residents and the ecological environment.

[0003] Clinker-free concrete is a concrete made with alkali-activated cementitious materials or all-solid waste cementitious materials that do not contain cement clinker. Alkali-activated cementitious materials generally use alkali activators such as water glass and sodium hydroxide to activate granulated blast furnace slag, fly ash and other mineral powder materials with pozzolanic activity to produce cementitious properties; all-solid waste cementitious materials are steel slag, ammonia-alkali white mud, red mud, calcium carbide slag and other materials that can hydrate and produce a large amount of OH - The use of industrial solid waste powders, along with industrial by-product gypsum, stimulates the formation of silica-alumina industrial solid waste powders, such as granulated blast furnace slag, fly ash, and coal-fired slag, to produce cementitious properties. To meet the needs of engineering construction and the "dual carbon" goals, utilizing industrial solid waste as a raw material for concrete and developing clinker-free, low-carbon concrete are key avenues for sustainable development in the concrete industry.

[0004] Patent CN 115745434 A (Clinker-free cementitious material containing a large amount of wet alkali-drainage slag, preparation method and application thereof) uses a composite activator of NaOH and Na2CO3 to activate wet alkali-drainage slag and slag to prepare a clinker-free cementitious material. However, NaOH and Na2CO3 are industrial products with high production costs and pollutant emissions during the production process. In addition, the 3d and 28d mortar compressive strengths of the cementitious material are low, with a maximum of only 12.5MPa and 34.7MPa.

[0005] Patent CN 117049805 A (Preparation Method of Cementitious Material Using Ammonia-Soda Mud, Slag, and Fly Ash as Raw Materials) requires airing, drying, and grinding of the ammonia-soda mud. Because the ammonia-soda mud particles are extremely fine, usually exist in agglomerates, and are highly absorbent, drying and grinding are difficult and costly.

[0006] Patent CN 112125633 A (C30 grade full solid waste concrete and its preparation method) uses ammonia alkali white mud-carbide slag to co-excite slag-fly ash to replace cement to prepare concrete, needs to stand the ammonia alkali white mud and carbide slag stock solution to stratify, respectively obtains ammonia alkali white mud, carbide slag upper clear liquid and lower slurry, controls the water content of lower slurry to 50%~60%, then naturally air-dries, crushes and sieves to obtain ammonia alkali white mud powder and carbide slag powder; When preparing concrete, the concentration and PH value of carbide slag upper clear liquid need to be controlled within a certain range, then added into concrete for mixing. The raw material processing and concrete preparation process described in the patent are complex, low in efficiency, difficult to control technical indicators, and low in actual feasibility. In addition, the 1d compressive strength of non-clinker cementitious material or concrete is not involved in the above patents.

[0007] Therefore, a method for preparing non-clinker concrete using ammonia alkali white mud without drying, low production cost and simple operation is needed. SUMMARY

[0008] The present application provides an early strength non-clinker concrete prepared by using ammonia alkali white mud and its preparation method, the ammonia alkali white mud does not need to be dried, no industrial products are added as activators in the non-clinker concrete, the chemical substances contained in the ammonia alkali white mud are used to accelerate the hydration reaction of the cementitious material by activating the slag powder-steel slag powder-gypsum cementitious system, to prepare early strength non-clinker concrete, and realize the resource utilization of ammonia alkali white mud and other solid wastes.

[0009] To achieve the above purpose, the present application is implemented according to the following technical scheme:

[0010] An early strength non-clinker concrete prepared by using ammonia alkali white mud, the components of which include, by mass fraction: ammonia alkali white mud 65~235 parts, slag powder 140~245 parts, steel slag powder 35~105 parts, industrial by-product gypsum 30~60 parts, fine aggregate 770~895 parts, coarse aggregate 1040~1070 parts, polycarboxylic acid water reducer 5~9 parts, and mixing water 120~166 parts.

[0011] Further, the ammonia alkali white mud is wet-based ammonia alkali white mud after pressure filtration, which is mechanically crushed to particles below 2mm; or the wet-based ammonia alkali white mud after pressure filtration is mechanically crushed, water is added and stirred into a slurry, and the water content of the slurry is controlled to be ≥140%; the slag powder is S95 grade granulated blast furnace slag powder; the steel slag powder is steel slag powder after crushing, magnetic separation and grinding treatment, and the specific surface area is ≥350m 2 / kg; the coarse aggregate is pebbles or crushed stones, with a particle size of 4.75 to 26.5 mm and a crushing index of ≤20%; the fine aggregate is natural sand or machine-made sand, with a particle size of 0.15 to 4.75 mm, a fineness modulus of 2.3 to 3.0, a mud content of <5.0%, or a stone powder content of <15.0%.

[0012] The present invention also provides a method for preparing early-strength clinker-free concrete using ammonia-alkali white mud, comprising the following steps:

[0013] A. Crush the wet-base ammonia-soda mud into particles less than 2 mm, take a sample of the ammonia-soda mud particles and dry it at 65°C to constant weight, and test its moisture content (a%) and liquid limit moisture content (b%), and adjust with water;

[0014] B. Feed coarse aggregate, fine aggregate, ammonia-soda mud, slag powder, steel slag powder and industrial by-product gypsum into a concrete mixer in the following proportions by weight: 1040-1070 parts of coarse aggregate, 770-895 parts of fine aggregate, 65-235 parts of ammonia-soda mud, 140-245 parts of slag powder, 35-105 parts of steel slag powder and 30-60 parts of industrial by-product gypsum, and stir for 30-60 seconds;

[0015] C. Add 50% to 80% of 120 to 166 parts of mixing water into the mixer and stir for 30 to 60 seconds; add 5 to 9 parts of polycarboxylate water reducer together with the remaining mixing water into the mixer and stir for 60 to 120 seconds to obtain a concrete mixture;

[0016] D. vibrating the concrete mixture into shape, covering it with a plastic film to retain moisture and then curing it to obtain an early-strength clinker-free concrete.

[0017] Furthermore, the water adjustment method includes: when the moisture content of the ammonia-soda white mud is measured to be a% < the liquid limit moisture content b%, additional water needs to be added, and the amount of added water is the dry basis ammonia-soda white mud mass m·(b%-a%);

[0018] When the moisture content of the ammonia-alkali white mud is measured to be a%>b%, the actual mixing water consumption of the concrete needs to be deducted from the water consumption in step C above, and the amount of water deducted is the mass of the dry ammonia-alkali white mud m·(a%-b%);

[0019] When ammonia-soda mud is used to prepare concrete in the form of a slurry, the moisture content of the ammonia-soda mud slurry is measured to be c%. Since c% ≥ 140%, it is higher than the liquid limit moisture content b% of the ammonia-soda mud. At this time, the actual mixing water consumption of the concrete needs to deduct part of the water consumption from the water consumption in the above step C. The deducted water amount is the dry basis ammonia-soda mud mass m·(c%-b%).

[0020] The beneficial effects of the present invention are:

[0021] The ammonia-soda white mud in the present invention does not need to be dried and can be used to prepare concrete after being crushed into fine particles or made into slurry; no industrial products are added as activators, which further reduces costs; the prepared clinker-free concrete has high early strength, with a 1-day compressive strength of ≥6.0 MPa, a 3-day compressive strength of ≥20.0 MPa, and a 28-day compressive strength of ≥35.0 MPa. DETAILED DESCRIPTION

[0022] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0023] The invention provides an early-strength clinker-free concrete, comprising the following components: ammonia-alkali white mud, slag powder, steel slag powder, industrial by-product gypsum, fine aggregate, coarse aggregate, a water reducer and mixing water. The early-strength clinker-free concrete comprises, by mass, 65-235 parts of ammonia-alkali white mud, 140-245 parts of slag powder, 35-105 parts of steel slag powder, 30-60 parts of industrial by-product gypsum, 770-895 parts of fine aggregate, 1040-1070 parts of coarse aggregate, 5-9 parts of polycarboxylate water reducer and 120-166 parts of mixing water. The concrete has a 1-day compressive strength of ≥6.0 MPa, a 7-day compressive strength of ≥20.0 MPa and a 28-day compressive strength of ≥35.0 MPa.

[0024] The ammonia-soda white mud used in the present invention is obtained by mechanically crushing the wet-base ammonia-soda white mud after filter pressing into particles of less than 2 mm; or by mechanically crushing the wet-base ammonia-soda white mud after filter pressing, adding water and stirring to form a slurry. In order to facilitate slurry pumping, the water content of the slurry is controlled to be ≥140%;

[0025] The present invention utilizes the chemical substances contained in the ammonia-soda white mud to stimulate the slag powder-steel slag powder-gypsum cementitious system, thereby accelerating the hydration reaction of the cementitious material and forming a higher early strength. Generally speaking, the hydration reaction rate of the slag powder-steel slag powder-gypsum cementitious system is relatively slow, mainly because the steel slag powder needs to be hydrated to release Ca(OH)2 to form an alkaline environment in the early stage. The glass contained in the slag powder gradually hydrates and dissociates in the alkaline environment to form silicate (aluminum) acid ions, which react with Ca(OH)2 to form hydrated calcium silicate (CSH) gel. At the same time, ettringite (AFt) is generated under the stimulation of gypsum, forming early strength. However, this process is relatively slow and takes 1 to 2 days to complete at room temperature. Therefore, the cementitious system generally has no strength after 1 day. When ammonia-soda mud is added, alkaline substances such as Ca(OH)2 in it quickly create an alkaline environment, accelerating the hydration and dissociation of the vitreous in the slag powder, forming CSH gel. Simultaneously, the large amount of soluble chlorides and sulfates in the mud react with the dissociated silicate (aluminum) ions to form complex salt precipitates such as AFt and Frieldel salt, thereby rapidly developing early strength. Clinker-free concrete containing ammonia-soda mud has a compressive strength of ≥6.0 MPa at 1 day, ≥20.0 MPa at 7 days, and ≥35.0 MPa at 28 days.

[0026] The present invention also provides a method for preparing this early-strength clinker-free concrete. In view of the characteristics of ammonia-soda mud that it has strong water absorption and is not easy to dry, the wet-base ammonia-soda mud in the present invention does not need to be dried, and can be used only after being mechanically crushed or made into a slurry. When the water content of the ammonia-soda mud is not higher than the liquid limit water content of the ammonia-soda mud, the water in the ammonia-soda mud exists in the form of non-free water such as crystallization water or adsorbed water. Therefore, when designing the concrete mix ratio, the ammonia-soda mud with a water content equal to the liquid limit water content is counted as a component of the concrete cementitious material, and the water in the ammonia-soda mud that is higher than the liquid limit water content is counted as mixing water, and this part of water is deducted when calculating the actual water consumption. The advantage of this is that the water-cement ratio and the amount of cementitious material used in the concrete can be designed according to the parameters of ordinary concrete, and the cohesiveness of the concrete is basically the same as that of ordinary concrete. If only the dry-base ammonia-alkali mud is counted as a component of the concrete cementitious material, and the water content in the ammonia-alkali mud is counted as mixing water, then this part of non-free water will also be deducted from the mixing water dosage when calculating the concrete mix ratio, resulting in a lower actual mixing water dosage, and thus a lower water-cement ratio of the concrete and a higher total amount of cementitious materials, causing the concrete to be too sticky and inconvenient to construct.

[0027] Example 1:

[0028] 1. Prepare early-strength clinker-free concrete with ammonia-alkali white mud, slag powder, steel slag powder, desulfurized gypsum, fine aggregate, coarse aggregate, polycarboxylic acid water reducer and water. The specific mix proportions are shown in Table 1.

[0029] Table 1 Concrete mix ratio (kg / m3 )

[0030]

[0031] 2. The water content of ammonia-soda mud is 53%, and the liquid limit water content is 105%. Use a crusher to crush the ammonia-soda mud into particles less than 2 mm;

[0032] 3. Purchased steel slag powder, with a specific surface area of ​​360m 2 / kg;

[0033] 4. Purchase S95 grade granulated blast furnace slag powder with a specific surface area of ​​410m 2 / kg;

[0034] 5. Purchase desulfurization gypsum from power plants and pass it through a 2.36mm square hole sieve;

[0035] 6. The fineness modulus of machine-made sand is 2.9, which belongs to medium sand in zone II;

[0036] 7. The crushed stone is 4.95-19.0mm continuously graded limestone with a crushing index of 11.8%;

[0037] 8. Early strength clinker-free concrete is prepared according to the following steps:

[0038] (1) The measured water content of the ammonia-soda mud is 53%, which is less than its liquid limit water content of 105%. The mass of the dry ammonia-soda mud is 74÷(1+53%)=48.4 kg;

[0039] (2) Each cubic meter of concrete requires an additional amount of water: 48.4 × (105% - 53%) = 25.2 kg;

[0040] (3) The actual mixing water consumption per cubic meter of concrete is 150 + 25.2 = 175.2 kg;

[0041] (4) Crushed stone, machine-made sand, ammonia-alkali white mud particles, slag powder, steel slag powder and desulfurized gypsum were sequentially fed into a concrete mixer according to the mix ratio in Table 1 and stirred for 30 seconds;

[0042] (5) Add 100 kg of mixing water into the mixer and stir for 30 seconds;

[0043] (6) Finally, 6.3 kg of polycarboxylate water reducer and the remaining 75.2 kg of mixing water were added to the mixer and stirred for 60 seconds to obtain an early strength clinker-free concrete mixture with a test slump of 160 mm;

[0044] (7) The concrete mixture was placed into a 150 mm × 150 mm × 150 mm mold, compacted on a concrete compaction table, and covered with a plastic film;

[0045] (8) Place the mold filled with concrete in a curing room at 20±2℃ and relative humidity ≥95%, remove the mold after curing for 24 hours, and continue to place it in the curing room for curing to the design age, which is the early strength clinker-free concrete.

[0046] 9. The compressive strength of the concrete at 1 day is 8.0 MPa, at 7 days it is 31.1 MPa, and at 28 days it is 43.6 MPa.

[0047] The difference from Example 1 is that this comparative example does not add ammonia-soda white mud, and other raw materials are the same.

[0048] 1. Prepare clinker-free concrete with slag powder, steel slag powder, desulfurized gypsum, fine aggregate, coarse aggregate, polycarboxylate water reducer and water. The specific mix proportions are shown in Table 2.

[0049] Table 2 Concrete mix ratio (kg / m 3 )

[0050]

[0051] 2. Clinker-free concrete is prepared according to the following steps:

[0052] (1) Crushed stone, machine-made sand, slag powder, steel slag powder and desulfurized gypsum were fed into a concrete mixer in the proportions shown in Table 2 and stirred for 30 seconds.

[0053] (2) Add 100 kg of mixing water into the mixer and stir for 30 seconds;

[0054] (3) Finally, 5.6 kg of polycarboxylate water reducer and the remaining 50 kg of mixing water were added to the mixer and stirred for 60 seconds to obtain a clinker-free concrete mixture with a slump of 150 mm.

[0055] (4) The concrete mixture was placed into a 150 mm × 150 mm × 150 mm mold, compacted on a concrete compaction table, and covered with a plastic film;

[0056] (5) Place the mold filled with concrete in a curing room at 20±2℃ and relative humidity ≥95%. If it is not completely hardened after 24 hours of curing, it cannot be demoulded. If it can be demoulded after 48 hours of curing, and then continue to be placed in the curing room for curing to the design age, it is clinker-free concrete.

[0057] 3. The concrete has no strength at 1 day; the compressive strength at 7 days is 19.5 MPa; and the compressive strength at 28 days is 41.3 MPa. Example 2:

[0058] 1. Prepare early-strength clinker-free concrete with ammonia-alkali white mud, slag powder, steel slag powder, desulfurized gypsum, fine aggregate, coarse aggregate, polycarboxylic acid water reducer and water. The specific mix proportions are shown in Table 3.

[0059] Table 3 Concrete mix ratio (kg / m 3 )

[0060]

[0061] 2. The water content of ammonia-soda mud is 125%, and the liquid limit water content is 105%. Use a crusher to crush the ammonia-soda mud into particles less than 2 mm;

[0062] 3. Purchased steel slag powder, with a specific surface area of ​​360m 2 / kg;

[0063] 4. Purchase S95 grade granulated blast furnace slag powder with a specific surface area of ​​410m 2 / kg;

[0064] 5. Purchase desulfurization gypsum from power plants and pass it through a 2.36mm square hole sieve;

[0065] 6. The fineness modulus of machine-made sand is 2.9, which belongs to medium sand in zone II;

[0066] 7. The crushed stone is 4.95-19.0mm continuously graded limestone with a crushing index of 11.8%;

[0067] 8. Early strength clinker-free concrete is prepared according to the following steps:

[0068] (1) The measured moisture content of the ammonia-soda mud is 125%, which is greater than its liquid limit moisture content of 105%. The mass of the dry ammonia-soda mud is 148÷(1+125%)=65.8 kg;

[0069] (2) The water content of each cubic meter of concrete needs to be deducted by 65.8×(125%-105%)=13.2 kg;

[0070] (3) The actual mixing water consumption per cubic meter of concrete is 160-13.2=146.8 kg;

[0071] (4) Gravel, machine-made sand, ammonia-alkali white mud particles, slag powder, steel slag powder and desulfurized gypsum were sequentially fed into a concrete mixer according to the mix ratio in Table 3 and stirred for 30 seconds;

[0072] (5) Add 100 kg of mixing water into the mixer and stir for 30 seconds;

[0073] (5) Finally, 6.0 kg of polycarboxylate water reducer and the remaining 46.8 kg of mixing water were added to the mixer and stirred for 60 seconds to obtain an early-strength clinker-free concrete mixture with a test slump of 170 mm;

[0074] (6) The concrete mixture was placed into a 150 mm × 150 mm × 150 mm mold, compacted on a concrete compaction table, and covered with a plastic film;

[0075] (7) Place the mold filled with concrete in a curing room at 20±2℃ and relative humidity ≥95%, remove the mold after curing for 24 hours, and continue to place it in the curing room for curing to the design age, which is the early strength clinker-free concrete.

[0076] 9. The concrete has a 1d compressive strength of 7.3MPa, a 7d compressive strength of 26.0MPa, and a 28d compressive strength of 37.3MPa.

[0077] Example 3:

[0078] 1. Prepare early-strength clinker-free concrete with ammonia-alkali white mud slurry, slag powder, steel slag powder, desulfurized gypsum, fine aggregate, coarse aggregate, polycarboxylic acid water reducer and water. The specific mix proportions are shown in Table 4.

[0079] Table 4 Concrete mix ratio (kg / m 3 )

[0080]

[0081] 2. The water content of ammonia-alkali white mud slurry is 145%, and the liquid limit water content is 105%;

[0082] 3. Purchased steel slag powder, with a specific surface area of ​​360m 2 / kg;

[0083] 4. Purchase S95 grade granulated blast furnace slag powder with a specific surface area of ​​410m 2 / kg;

[0084] 5. Purchase desulfurization gypsum from power plants and pass it through a 2.36mm square hole sieve;

[0085] 6. The fineness modulus of machine-made sand is 2.9, which belongs to medium sand in zone II;

[0086] 7. The crushed stone is 4.95-19.0mm continuously graded limestone with a crushing index of 11.8%;

[0087] 8. Early strength clinker-free concrete is prepared according to the following steps:

[0088] (1) The water content of the ammonia-soda white mud slurry was measured to be 145%, which is greater than its liquid limit water content of 105%. The mass of the dry ammonia-soda white mud was 170÷(1+145%)=69.4 kg;

[0089] (2) The water content of each cubic meter of concrete needs to be deducted by 69.4 × (145% - 105%) = 27.8 kg;

[0090] (3) The actual mixing water consumption per cubic meter of concrete is 162-27.8=134.2 kg;

[0091] (4) Crushed stone, machine-made sand, ammonia-alkali white mud slurry, slag powder, steel slag powder and desulfurized gypsum were fed into a concrete mixer in the proportions shown in Table 4 and stirred for 30 seconds;

[0092] (5) Add 100 kg of mixing water into the mixer and stir for 30 seconds;

[0093] (6) Finally, 7.7 kg of polycarboxylate water reducer and the remaining 34.2 kg of mixing water were added to the mixer and stirred for 60 seconds to obtain an early strength clinker-free concrete mixture with a test slump of 170 mm;

[0094] (7) The concrete mixture was placed into a 150 mm × 150 mm × 150 mm mold, compacted on a concrete compaction table, and covered with a plastic film;

[0095] (8) Place the mold filled with concrete in a curing room at 20±2℃ and relative humidity ≥95%, remove the mold after curing for 24 hours, and continue to place it in the curing room for curing to the design age, which is the early strength clinker-free concrete.

[0096] 9. The concrete has a 1d compressive strength of 7.9MPa, a 7d compressive strength of 26.9MPa, and a 28d compressive strength of 39.8MPa.

[0097] Example 4:

[0098] 1. Prepare early-strength clinker-free concrete with ammonia-alkali white mud, slag powder, steel slag powder, desulfurized gypsum, fine aggregate, coarse aggregate, polycarboxylic acid water reducer and water. The specific mix proportions are shown in Table 5.

[0099] Table 5 Concrete mix ratio (kg / m 3 )

[0100]

[0101] 2. The water content of ammonia-soda mud is 53%, and the liquid limit water content is 105%. Use a crusher to crush the ammonia-soda mud into particles less than 2 mm;

[0102] 3. Purchased steel slag powder, with a specific surface area of ​​360m 2 / kg;

[0103] 4. Purchase S95 grade granulated blast furnace slag powder with a specific surface area of ​​410m 2 / kg;

[0104] 5. Purchase desulfurization gypsum from power plants and pass it through a 2.36mm square hole sieve;

[0105] 6. The fineness modulus of machine-made sand is 2.9, which belongs to medium sand in zone II;

[0106] 7. The crushed stone is 4.95-19.0mm continuously graded limestone with a crushing index of 11.8%;

[0107] 8. Early strength clinker-free concrete is prepared according to the following steps:

[0108] (1) The measured water content of ammonia-soda white mud is 53%, which is less than its liquid limit water content of 105%. Each cubic meter of concrete requires additional water of 220÷(1+53%)×(105%-53%)=74.8 kg;

[0109] (2) The actual mixing water consumption per cubic meter of concrete is 154 + 74.8 = 228.8 kg;

[0110] (3) Gravel, machine-made sand, ammonia-soda mud particles, slag powder, steel slag powder and desulfurized gypsum were sequentially fed into a concrete mixer according to the mix ratio in Table 5 and stirred for 30 seconds;

[0111] (4) Add 150 kg of mixing water into the mixer and stir for 60 seconds;

[0112] (5) Finally, 10.5 kg of polycarboxylate water reducer and the remaining 78.8 kg of mixing water were added to the mixer and stirred for 60 seconds to obtain an early-strength clinker-free concrete mixture with a test slump of 180 mm.

[0113] (6) The concrete mixture was placed into a 150 mm × 150 mm × 150 mm mold, compacted on a concrete compaction table, and covered with a plastic film;

[0114] (7) Place the mold filled with concrete in a curing room at 20±2℃ and relative humidity ≥95%, remove the mold after curing for 24 hours, and continue to place it in the curing room for curing to the design age, which is the early strength clinker-free concrete.

[0115] 9. The concrete has a 1d compressive strength of 8.6MPa, a 7d compressive strength of 31.7MPa, and a 28d compressive strength of 47.5MPa.

[0116] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for preparing early-strength clinker-free concrete prepared using ammonia-alkali white mud, characterized in that: The early-strength clinker-free concrete comprises, by mass, 65-235 parts of ammonia-alkali white mud, 140-245 parts of slag powder, 35-105 parts of steel slag powder, 30-60 parts of industrial by-product gypsum, 770-895 parts of fine aggregate, 1040-1070 parts of coarse aggregate, 5-9 parts of polycarboxylic acid water reducer, and 120-166 parts of mixing water. The ammonia-alkali white mud is obtained by mechanically crushing the wet-base ammonia-alkali white mud after filter pressing into particles of less than 2 mm; or the wet-base ammonia-alkali white mud after filter pressing is mechanically crushed and then stirred into a slurry with water, and the moisture content of the slurry is controlled to be ≥140%; the slag powder is S95 grade granulated blast furnace slag powder; and the steel slag powder is steel slag powder after crushing, magnetic separation and grinding, with a specific surface area of ​​≥350 m 2 / kg; the particle size of the coarse aggregate is 4.75~26.5mm, and the crushing index is ≤20%; the preparation method of the early-strength clinker-free concrete comprises the following steps: When using wet-base ammonia-soda mud particles crushed to less than 2 mm to prepare concrete, first take a sample of the ammonia-soda mud particles and dry it at 65°C to constant weight. The moisture content is a% and the liquid limit moisture content is b%, respectively, and the water consumption is adjusted. When using ammonia-soda mud slurry to prepare concrete, the measured moisture content of the ammonia-soda mud slurry is c%. Since c% is ≥ 140%, it is higher than the liquid limit moisture content of the ammonia-soda mud, b%. At this time, the actual mixing water consumption of the concrete needs to deduct some water from the water consumption. The deducted water amount is the dry-base ammonia-soda mud mass m·(c%-b%). B. Feed coarse aggregate, fine aggregate, ammonia-soda mud, slag powder, steel slag powder and industrial by-product gypsum into a concrete mixer in the following proportions by weight: 1040-1070 parts of coarse aggregate, 770-895 parts of fine aggregate, 65-235 parts of ammonia-soda mud, 140-245 parts of slag powder, 35-105 parts of steel slag powder and 30-60 parts of industrial by-product gypsum, and mix for 30-60 seconds; C. First, add 50% to 80% of the total amount of 120 to 166 parts of the mixing water into the mixer and stir for 30 to 60 seconds; then, add 5 to 9 parts of the polycarboxylate water reducer and the remaining mixing water into the mixer and stir for 60 to 120 seconds to obtain a concrete mixture; D. vibrating the concrete mixture into a shape, placing it in a curing room at 20±2° C. and relative humidity ≥95%, covering it with a plastic film to maintain moisture for 24 hours, and then demolding to obtain an early-strength clinker-free concrete; The method for adjusting the water consumption includes: when the moisture content of the ammonia-soda white mud is measured to be a%<b%, additional water needs to be added on the basis of the water consumption, and the amount of additional water is the dry basis ammonia-soda white mud mass m·(b%-a%); When the moisture content of ammonia-alkali mud is measured to be a%>b%, the actual mixing water consumption of concrete needs to deduct part of the water from the water consumption, and the deducted water amount is the dry basis ammonia-alkali mud mass m·(a%-b%).

2. The method for preparing the early-strength clinker-free concrete prepared by ammonia-soda white mud according to claim 1, wherein: The compressive strength of the concrete after standard curing for one day after molding is ≥6.0 MPa, the compressive strength after seven days is ≥20.0 MPa, and the compressive strength after twenty-eight days is ≥35.0 MPa.

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