Preparation method of zero clinker ultra-high performance concrete by using waste incineration bottom ash for gradient grading

Abstract

The application discloses a kind of gradient hierarchical utilization garbage incineration bottom ash preparation's zero clinker ultra-high performance concrete and its preparation method, including following weight parts raw materials: garbage incineration bottom ash 660-700 parts;Mineral powder 460-500 parts;Silica fume 35-45 parts;Fine quartz sand 380-420 parts;Activator 370-380 parts;Modifier 15-17 parts;Steel fiber 110-130 parts.Garbage incineration bottom ash includes following particle size and weight parts garbage incineration bottom ash: 8 μm below garbage incineration bottom ash 35-45 parts;8-40 μm garbage incineration bottom ash 75-85 parts;40-150 μm garbage incineration bottom ash 150-170 parts;150-500 μm garbage incineration bottom ash 380-420 parts.The application cooperates and utilizes garbage incineration bottom ash, mineral powder and silica fume, and does not use Portland cement as UHPC cementing material raw material, and UHPC preparation cost and carbon emission are greatly reduced.

Description

Gradient-graded zero-clinker ultra-high performance concrete prepared using waste incineration bottom ash and its preparation method Technical Field

[0001] This invention belongs to the field of solid waste resource utilization technology, and in particular relates to a zero-clinker ultra-high performance concrete prepared by gradient-grade utilization of waste incineration bottom ash and its preparation method. Background Technology

[0002] Waste-to-energy incineration technology enables large-scale reduction and resource recovery of municipal solid waste, and is now widely used worldwide. Waste incineration ash is a byproduct of waste-to-energy incineration, accounting for approximately 20%–30% of the mass of incinerated municipal solid waste, with bottom ash comprising about 80% of the total. In my country, bottom ash is classified as general industrial solid waste and can be disposed of via landfill. However, with the rapid pace of industrialization and urbanization in my country and the increasing volume of municipal solid waste incinerated, the amount of bottom ash generated is rising annually, resulting in a massive accumulation. Simply landfilling bottom ash would inevitably occupy a large amount of land resources and pose a risk of secondary pollution to the surrounding environment and groundwater. Since the basic chemical composition of bottom ash is CaO, SiO2, Al2O3, and Fe2O3, it has the potential for use as a building material. Currently, there are existing examples both domestically and internationally of using waste incineration ash to produce cement concrete, roadbed materials, and non-sintered bricks, but the comprehensive utilization rate and added value of these ash products remain generally low. Therefore, there is an urgent need to develop new high-performance building materials and their preparation processes to achieve large-scale disposal and high-value-added resource utilization of waste incineration ash.

[0003] Ultra-high performance concrete (UHPC), as a new generation of concrete technology, is a novel cement-based composite material made from raw materials such as cement, admixtures, aggregates, fibers, additives, and water. It possesses high toughness, structural reliability, durability, and ultra-high strength. Its core design theory achieves ultra-high performance by improving the microstructure of the cement paste matrix and the interfacial structure between the cement paste and aggregates. Specifically, this includes: limiting the maximum aggregate size to improve the uniformity of the UHPC matrix and reduce internal defects; optimizing particle size distribution to increase the bulk density of UHPC; adding ultrafine active mineral admixtures such as silica fume to leverage their micro-aggregate effect and pozzolanic effect, thereby reducing matrix porosity and increasing density; and introducing steel fibers or other types of fibers to enhance the toughness of UHPC. These factors result in UHPC having mechanical properties and durability far superior to traditional concrete, giving it enormous application potential and broad prospects in modern engineering. However, the preparation of UHPC involves the extensive use of high-grade silicate cement, silica fume, fine silica sand, and high-performance water-reducing agents, inevitably leading to high costs, high energy consumption, and high carbon emissions. Using waste incineration ash as a raw material for UHPC preparation could effectively reduce the production cost and overall carbon emissions, while simultaneously enabling large-scale utilization and high-value-added resource utilization of waste incineration ash, resulting in significant economic and environmental benefits.

[0004] However, due to the low activity and poor cementitious properties of the pozzolanic ash from waste incineration bottom ash, the hydration environment of ordinary silicate cement-based UHPC is insufficient to activate the pozzolanic activity of the waste incineration bottom ash. Therefore, if waste incineration bottom ash is used as an admixture in ordinary silicate cement-based UHPC, it will inevitably have a serious adverse effect on the mechanical properties and durability of UHPC. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides a zero-clinker ultra-high performance concrete (UHPC) prepared by gradient-grade utilization of waste incineration bottom ash and its preparation method. This invention uses waste incineration bottom ash, along with mineral powder and silica fume as precursors, as alkali-activated materials to prepare low-carbon UHPC. On the one hand, it can provide a matching alkaline activation environment for waste incineration bottom ash, thereby fully activating the reactivity of waste incineration bottom ash and enhancing the mechanical properties of the matrix; on the other hand, it can synergistically utilize various industrial solid wastes to prepare zero-cement clinker UHPC, greatly reducing the production cost, energy consumption, and carbon emissions of UHPC.

[0006] This invention is achieved as follows: a zero-clinker ultra-high performance concrete prepared by gradient grading using waste incineration bottom ash, comprising the following raw materials in parts by weight: 660-700 parts waste incineration bottom ash; 460-500 parts mineral powder; 35-45 parts silica fume; 380-420 parts fine quartz sand; 370-380 parts activator; 15-17 parts modifier; and 110-130 parts steel fiber.

[0007] In the above technical solution, preferably, the waste incineration bottom ash is obtained by grinding and classifying the raw bottom ash of municipal solid waste incineration into different particle sizes, and then fully mixing and homogenizing the bottom ash of different particle sizes, including the following particle sizes and weight parts of waste incineration bottom ash: 35-45 parts of waste incineration bottom ash with a particle size of less than 8μm; 75-85 parts of waste incineration bottom ash with a particle size of 8-40μm; 150-170 parts of waste incineration bottom ash with a particle size of 40-150μm; and 380-420 parts of waste incineration bottom ash with a particle size of 150-500μm.

[0008] In the above technical solution, preferably, the mineral powder is obtained by grinding granulated blast furnace slag to below 40μm.

[0009] In the above technical solution, preferably, the SiO2 content in the silica fume is greater than 95%, and the particle size is less than 8μm.

[0010] In the above technical solution, preferably, the fine quartz sand has a particle size of 150-500μm.

[0011] In the above technical solution, preferably, the activator comprises the following raw materials in parts by weight: 38-43 parts of industrial-grade sodium hydroxide with a content ≥90%; 230-235 parts of water glass with a modulus range of 3.41-3.60; and 95-105 parts of water.

[0012] In the above technical solution, preferably, the modifier comprises the following raw materials in parts by weight: 3-5 parts of industrial grade sodium gluconate with a content ≥98%; and 10-14 parts of quicklime powder with a content ≥95%.

[0013] In the above technical solution, preferably, the steel fiber has a length of 10mm and a diameter of 0.12mm.

[0014] The above-mentioned gradient grading method for preparing zero-clinker ultra-high performance concrete using waste incineration bottom ash includes the following preparation steps:

[0015] Step 1: Weigh out the waste incineration bottom ash, mineral powder, silica fume, fine quartz sand, activator, modifier and steel fiber according to the formula;

[0016] Step 2: Pour the weighed waste incineration bottom ash, mineral powder, silica fume, fine quartz sand and modifier into a planetary mortar mixer and mix for 2-3 minutes until they are evenly mixed.

[0017] Step 3: Pour the activator into the mixture obtained in Step 2 and continue stirring for 3-5 minutes;

[0018] Step 4: Pour the steel fibers into the mixture obtained in Step 3, continue stirring for 2-3 minutes, and after casting and curing, obtain the zero-clinker ultra-high performance concrete prepared by gradient grading using waste incineration bottom ash.

[0019] In the above technical solution, preferably, the preparation process of the activator is as follows: Sodium hydroxide, water glass and water are weighed according to the formula amount, the sodium hydroxide is dissolved in water and stirred thoroughly, then mixed with water glass, and after thorough mixing, it is sealed and allowed to stand, and cooled to room temperature to obtain the activator.

[0020] The advantages and positive effects of this invention are:

[0021] (1) Due to the wide particle size distribution and poor cementing activity of waste incineration bottom ash, this invention innovatively utilizes grading and sorting technology when preparing zero clinker UHPC using waste incineration bottom ash. The waste incineration bottom ash with a wide particle size distribution is first graded by particle size and then re-optimized by particle size matching: coarse-grained waste incineration bottom ash of 150-500μm is used as UHPC aggregate to partially replace fine quartz sand; waste incineration bottom ash of 40-150μm is used as inert filler in UHPC cementitious material; waste incineration bottom ash of 8-40μm is used as cementing reactant in UHPC cementitious material to partially replace mineral powder; and fine-grained waste incineration bottom ash of less than 8μm is used as active fine filler in UHPC cementitious material to partially replace silica fume. This allows for a narrower particle size range in waste incineration bottom ash, thereby fully utilizing the filling / cementing physicochemical properties of bottom ash at various particle sizes, reducing the amount of fine quartz sand, mineral powder, and silica fume used in UHPC, and significantly reducing the preparation cost of UHPC. On the other hand, by optimizing the particle size matching of waste incineration bottom ash of different particle sizes, the most compact packing effect can be achieved, ensuring the mechanical properties of UHPC under the premise of zero clinker use, realizing the low-carbon preparation of UHPC and the high-value-added utilization of waste incineration bottom ash.

[0022] (2) Since the alkali-activated cementitious material used in zero-clinker UHPC has a short setting time and large drying shrinkage, this invention innovatively introduces sodium gluconate and quicklime powder as modifiers when preparing zero-clinker UHPC using waste incineration bottom ash: the adsorption-complexation effect of sodium gluconate in the ionic environment of cementitious material is used to inhibit the early alkali-aluminosilicate reaction of cementitious material, thereby prolonging the setting time of zero-clinker UHPC and improving its workability; quicklime powder is introduced to supplement the calcium content of the cementitious material reaction system, induce the reaction products of the cementitious system to transform from NASH gel to CASH gel, enhance the product space filling, thereby reducing the drying shrinkage of zero-clinker UHPC and improving its long-term performance.

[0023] (3) The zero-clinker UHPC prepared by gradient grading using waste incineration bottom ash in this invention, under standard curing conditions, achieves a 3-day compressive strength of 92–96 MPa and a flexural strength of 13–15 MPa; a 7-day compressive strength of 122–128 MPa and a flexural strength of 17–22 MPa; and a 28-day compressive strength of 155–165 MPa and a flexural strength of 24–30 MPa. Both early and late-stage strengths meet the mechanical performance requirements of UHPC.

[0024] (4) The zero-clinker UHPC prepared by gradient gradation using waste incineration bottom ash in this invention utilizes industrial solid wastes such as waste incineration bottom ash, mineral powder and silica fume in synergy, without using silicate cement as raw material for UHPC cementing material, thereby greatly reducing the preparation cost and carbon emissions of UHPC, and has extremely high environmental and economic benefits.

[0025] (5) The zero-clinker UHPC prepared by gradient grading of waste incineration bottom ash in this invention can achieve a total content of more than 55% of waste incineration bottom ash while ensuring mechanical properties, thus realizing the application of waste incineration bottom ash, a major industrial solid waste, with large content and high added value.

[0026] (6) The zero-clinker UHPC prepared by gradient grading using waste incineration bottom ash in this invention has a drying shrinkage reduction of more than 31% compared with ordinary UHPC based on silicate cement, thereby ensuring the long-term performance of UHPC. Attached Figure Description

[0027] Figure 1 shows the drying shrinkage values ​​of UHPC prepared in various embodiments and comparative examples of the present invention. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0029] Example 1:

[0030] Weigh the following raw material components by weight: 460 parts mineral powder; 45 parts silica fume; 420 parts fine quartz sand; 130 parts steel fiber; 35 parts waste incineration bottom ash below 8μm; 85 parts waste incineration bottom ash between 8-40μm; 170 parts waste incineration bottom ash between 40-150μm; 380 parts waste incineration bottom ash between 150-500μm; 38 parts sodium hydroxide; 230 parts water glass; 105 parts water; 3 parts sodium gluconate; and 14 parts quicklime powder.

[0031] The preparation method is as follows: Dissolve the weighed sodium hydroxide in water and stir thoroughly. Pour the resulting sodium hydroxide solution into the weighed water glass and stir in one step until the mixture is uniform. Seal the resulting solution and let it stand and cool to room temperature to obtain the activator. Pour the weighed mineral powder, silica fume, fine quartz sand, waste incineration bottom ash of different particle sizes, sodium gluconate and quicklime powder into a planetary mortar mixer and stir for 3 minutes to make it dry and uniform. Pour the cooled activator solution into the above dry mixture and continue stirring for 4 minutes. Then pour the weighed steel fiber into the above mixture and continue stirring for 3 minutes. After stirring, cast the obtained fresh UHPC and cure it to obtain zero clinker UHPC prepared by gradient grading using waste incineration bottom ash.

[0032] Example 2:

[0033] Weigh the following raw material components by weight: 500 parts mineral powder; 45 parts silica fume; 420 parts fine quartz sand; 110 parts steel fiber; 35 parts waste incineration bottom ash below 8μm; 75 parts waste incineration bottom ash of 8-40μm; 170 parts waste incineration bottom ash of 40-150μm; 380 parts waste incineration bottom ash of 150-500μm; 43 parts sodium hydroxide; 230 parts water glass; 105 parts water; 5 parts sodium gluconate; and 10 parts quicklime powder.

[0034] The preparation method is as follows: Dissolve the weighed sodium hydroxide in water and stir thoroughly. Pour the resulting sodium hydroxide solution into the weighed water glass and stir in one step until the mixture is uniform. Seal the resulting solution and let it stand and cool to room temperature to obtain the activator. Pour the weighed mineral powder, silica fume, fine quartz sand, waste incineration bottom ash of different particle sizes, sodium gluconate and quicklime powder into a planetary mortar mixer and stir for 3 minutes to make it dry and uniform. Pour the cooled activator solution into the above dry mixture and continue stirring for 4 minutes. Then pour the weighed steel fiber into the above mixture and continue stirring for 3 minutes. After stirring, cast the obtained fresh UHPC and cure it to obtain zero clinker UHPC prepared by gradient grading using waste incineration bottom ash.

[0035] Example 3:

[0036] Weigh the following raw material components by weight: 500 parts mineral powder; 35 parts silica fume; 380 parts fine quartz sand; 130 parts steel fiber; 45 parts waste incineration bottom ash below 8μm; 75 parts waste incineration bottom ash between 8-40μm; 150 parts waste incineration bottom ash between 40-150μm; 420 parts waste incineration bottom ash between 150-500μm; 43 parts sodium hydroxide; 230 parts water glass; 105 parts water; 5 parts sodium gluconate; and 10 parts quicklime powder.

[0037] The preparation method is as follows: Dissolve the weighed sodium hydroxide in water and stir thoroughly. Pour the resulting sodium hydroxide solution into the weighed water glass and stir in one step until the mixture is uniform. Seal the resulting solution and let it stand and cool to room temperature to obtain the activator. Pour the weighed mineral powder, silica fume, fine quartz sand, waste incineration bottom ash of different particle sizes, sodium gluconate and quicklime powder into a planetary mortar mixer and stir for 3 minutes to make it dry and uniform. Pour the cooled activator solution into the above dry mixture and continue stirring for 4 minutes. Then pour the weighed steel fiber into the above mixture and continue stirring for 3 minutes. After stirring, cast the obtained fresh UHPC and cure it to obtain zero clinker UHPC prepared by gradient grading using waste incineration bottom ash.

[0038] Example 4:

[0039] Weigh the following raw material components by weight: 480 parts mineral powder; 45 parts silica fume; 380 parts fine quartz sand; 110 parts steel fiber; 35 parts waste incineration bottom ash below 8μm; 75 parts waste incineration bottom ash of 8-40μm; 170 parts waste incineration bottom ash of 40-150μm; 420 parts waste incineration bottom ash of 150-500μm; 40 parts sodium hydroxide; 235 parts water glass; 95 parts water; 3 parts sodium gluconate; and 14 parts quicklime powder.

[0040] The preparation method is as follows: Dissolve the weighed sodium hydroxide in water and stir thoroughly. Pour the resulting sodium hydroxide solution into the weighed water glass and stir in one step until the mixture is uniform. Seal the resulting solution and let it stand and cool to room temperature to obtain the activator. Pour the weighed mineral powder, silica fume, fine quartz sand, waste incineration bottom ash of different particle sizes, sodium gluconate and quicklime powder into a planetary mortar mixer and stir for 3 minutes to make it dry and uniform. Pour the cooled activator solution into the above dry mixture and continue stirring for 4 minutes. Then pour the weighed steel fiber into the above mixture and continue stirring for 3 minutes. After stirring, cast the obtained fresh UHPC and cure it to obtain zero clinker UHPC prepared by gradient grading using waste incineration bottom ash.

[0041] Example 5:

[0042] Weigh the following raw material components by weight: 490 parts mineral powder; 35 parts silica fume; 400 parts fine quartz sand; 120 parts steel fiber; 45 parts waste incineration bottom ash below 8μm; 80 parts waste incineration bottom ash between 8-40μm; 160 parts waste incineration bottom ash between 40-150μm; 400 parts waste incineration bottom ash between 150-500μm; 40 parts sodium hydroxide; 235 parts water glass; 105 parts water; 4 parts sodium gluconate; and 12 parts quicklime powder.

[0043] The preparation method is as follows: Dissolve the weighed sodium hydroxide in water and stir thoroughly. Pour the resulting sodium hydroxide solution into the weighed water glass and stir in one step until the mixture is uniform. Seal the resulting solution and let it stand and cool to room temperature to obtain the activator. Pour the weighed mineral powder, silica fume, fine quartz sand, waste incineration bottom ash of different particle sizes, sodium gluconate and quicklime powder into a planetary mortar mixer and stir for 3 minutes to make it dry and uniform. Pour the cooled activator solution into the above dry mixture and continue stirring for 4 minutes. Then pour the weighed steel fiber into the above mixture and continue stirring for 3 minutes. After stirring, cast the obtained fresh UHPC and cure it to obtain zero clinker UHPC prepared by gradient grading using waste incineration bottom ash.

[0044] Example 6:

[0045] Weigh the following raw material components by weight: 460 parts mineral powder; 45 parts silica fume; 410 parts fine quartz sand; 130 parts steel fiber; 35 parts waste incineration bottom ash below 8μm; 80 parts waste incineration bottom ash of 8-40μm; 170 parts waste incineration bottom ash of 40-150μm; 390 parts waste incineration bottom ash of 150-500μm; 42 parts sodium hydroxide; 230 parts water glass; 98 parts water; 4 parts sodium gluconate; and 12 parts quicklime powder.

[0046] The preparation method is as follows: Dissolve the weighed sodium hydroxide in water and stir thoroughly. Pour the resulting sodium hydroxide solution into the weighed water glass and stir in one step until the mixture is uniform. Seal the resulting solution and let it stand and cool to room temperature to obtain the activator. Pour the weighed mineral powder, silica fume, fine quartz sand, waste incineration bottom ash of different particle sizes, sodium gluconate and quicklime powder into a planetary mortar mixer and stir for 3 minutes to make it dry and uniform. Pour the cooled activator solution into the above dry mixture and continue stirring for 4 minutes. Then pour the weighed steel fiber into the above mixture and continue stirring for 3 minutes. After stirring, cast the obtained fresh UHPC and cure it to obtain zero clinker UHPC prepared by gradient grading using waste incineration bottom ash.

[0047] Comparative Example 1 (Standard UHPC):

[0048] Weigh the following raw material components by weight: 800 parts silicate cement; 200 parts silica fume; 800 parts fine quartz sand; 130 parts steel fiber; 200 parts water; 20 parts water-reducing agent.

[0049] The preparation method is as follows: Weigh out silicate cement, silica fume, and fine quartz sand and pour them into a planetary mortar mixer. Mix for 3 minutes to make the dry mixture uniform. Weigh out the water-reducing agent, mix it into water, and pour it into the above dry mixture after it is fully dissolved and mixed. Continue to mix for 4 minutes. Then, weigh out the steel fiber and pour it into the above mixture. Continue to mix for 3 minutes. After mixing, pour the obtained fresh UHPC into molds and cure it to obtain ordinary UHPC.

[0050] Comparative Example 2 (UHPC without modifiers):

[0051] Weigh the following raw material components by weight: 460 parts mineral powder; 45 parts silica fume; 420 parts fine quartz sand; 130 parts steel fiber; 35 parts waste incineration bottom ash below 8μm; 85 parts waste incineration bottom ash between 8-40μm; 170 parts waste incineration bottom ash between 40-150μm; 380 parts waste incineration bottom ash between 150-500μm; 38 parts sodium hydroxide; 230 parts water glass; and 105 parts water.

[0052] The preparation method is as follows: Dissolve the weighed sodium hydroxide in water and stir thoroughly. Pour the resulting sodium hydroxide solution into the weighed water glass and stir in one step until the mixture is uniform. Seal the resulting solution and let it stand and cool to room temperature to obtain the activator. Pour the weighed mineral powder, silica fume, fine quartz sand and waste incineration bottom ash of different particle sizes into a planetary mortar mixer and stir for 3 minutes to make it dry and uniform. Pour the cooled activator solution into the above dry mixture and continue stirring for 4 minutes. Then pour the weighed steel fiber into the above mixture and continue stirring for 3 minutes. After stirring, cast the obtained fresh UHPC and cure it to obtain zero clinker UHPC without the addition of modifier.

[0053] Comparative Example 3 (UHPC of zero clinker prepared from waste incineration bottom ash without particle size classification):

[0054] Weigh the following raw material components by weight: 460 parts mineral powder; 45 parts silica fume; 420 parts fine quartz sand; 130 parts steel fiber; 670 parts ungraded waste incineration bottom ash; 38 parts sodium hydroxide; 230 parts water glass; 105 parts water; 3 parts sodium gluconate; and 14 parts quicklime powder.

[0055] The preparation method is as follows: Dissolve the weighed sodium hydroxide in water and stir thoroughly. Pour the resulting sodium hydroxide solution into the weighed water glass and stir until uniformly mixed. Seal the resulting solution and let it stand and cool to room temperature to obtain the activator. Pour the weighed mineral powder, silica fume, fine quartz sand, waste incineration bottom ash that has not undergone particle size classification, sodium gluconate, and quicklime powder into a planetary mortar mixer and stir for 3 minutes to make it dry-mixed evenly. Pour the cooled activator solution into the above dry mixture and continue stirring for 4 minutes. Then pour the weighed steel fiber into the above mixture and continue stirring for 3 minutes. After stirring, cast the obtained fresh UHPC and cure it to obtain zero clinker UHPC prepared from waste incineration bottom ash that has not undergone particle size classification.

[0056] Comparative Example 4 (UHPC clinker from waste incineration bottom ash that has not undergone particle size classification and has not been mixed with modifiers):

[0057] Weigh the following raw material components by weight: 460 parts mineral powder; 45 parts silica fume; 420 parts fine quartz sand; 130 parts steel fiber; 670 parts ungraded waste incineration bottom ash; 38 parts sodium hydroxide; 230 parts water glass; and 105 parts water.

[0058] The preparation method is as follows: Dissolve the weighed sodium hydroxide in water and stir thoroughly. Pour the resulting sodium hydroxide solution into the weighed water glass and stir in one step until the mixture is uniform. Seal the resulting solution and let it stand and cool to room temperature to obtain the activator. Pour the weighed mineral powder, silica fume, fine quartz sand and the waste incineration bottom ash that has not undergone particle size classification into a planetary mortar mixer and stir for 3 minutes to make it dry and uniform. Pour the cooled activator solution into the above dry mixture and continue stirring for 4 minutes. Then pour the weighed steel fiber into the above mixture and continue stirring for 3 minutes. After stirring, cast the obtained fresh UHPC and cure it to obtain zero clinker UHPC of waste incineration bottom ash that has not undergone particle size classification and has not been modified.

[0059] The flowability of UHPC prepared from waste incineration bottom ash in Examples 1 to 6 and the UHPC prepared from Comparative Examples 1 to 4 were determined according to standard GB / T 2419-2005 "Method for Determination of Flowability of Cement Mortar". The compressive and flexural strengths of the UHPC prepared from waste incineration bottom ash in Examples 1 to 6 and the UHPC prepared from Comparative Examples 1 to 4 were determined according to standard GB / T 17671-2021 "Method for Testing the Strength of Cement Mortar". The drying shrinkage of the UHPC prepared from waste incineration bottom ash in Examples 1 to 6 and the UHPC prepared from Comparative Examples 1 to 4 was determined according to standard JC / T603-2004 "Method for Testing the Drying Shrinkage of Cement Mortar". All test blocks were prisms measuring 40mm × 40mm × 160mm. The results of the flowability, compressive strength, and flexural strength tests of UHPC are shown in Table 1, and the results of the drying shrinkage test of UHPC are shown in Figure 1.

[0060] Table 1. Flowability, compressive strength, and flexural strength of UHPC for each group

[0061]

[0062]

[0063] As shown in Table 1, the zero-clinker UHPC prepared by gradient gradation using waste incineration bottom ash in Examples 1 to 6, under standard curing conditions, achieved a 3-day compressive strength of 92–96 MPa and a flexural strength of 13–15 MPa; a 7-day compressive strength of 122–128 MPa and a flexural strength of 17–22 MPa; and a 28-day compressive strength of 155–165 MPa and a flexural strength of 24–30 MPa. Its early and later strengths are at the same level as the ordinary UHPC in Comparative Example 1, meeting the mechanical performance requirements of UHPC, and its workability is also improved compared to ordinary UHPC. In contrast, the zero-clinker UHPC prepared from waste incineration bottom ash in Examples 2 to 4 without the use of modifiers and / or without particle size classification showed a significant decrease in strength, and its workability was also significantly lower than that of the zero-clinker UHPC prepared from waste incineration bottom ash using gradient classification in Examples 1 to 6 and the ordinary UHPC in Comparative Example 1. This demonstrates the necessity of the modifiers and the preparation method using the particle size gradient classification of waste incineration bottom ash used in this invention.

[0064] As shown in Figure 1, the drying shrinkage values ​​of the various groups of UHPCs indicate that the zero-clinker UHPCs prepared by gradient grading using waste incineration bottom ash in Examples 1 to 6 exhibit a drying shrinkage reduction of over 31% compared to the ordinary UHPC in Comparative Example 1, providing reliable assurance for the long-term performance of the UHPCs. However, the drying shrinkage values ​​of the zero-clinker UHPCs without modifiers in Comparative Examples 2 and 4 are significantly higher than those of the zero-clinker UHPCs prepared by gradient grading using waste incineration bottom ash in Examples 1 to 6, demonstrating the effectiveness of the modifiers used in this invention in improving the drying shrinkage of the zero-clinker UHPCs prepared by gradient grading using waste incineration bottom ash.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A zero-clinker ultra-high performance concrete prepared by gradient grading using waste incineration bottom ash, characterized in that: The raw materials include the following parts by weight: 660-700 parts of waste incineration bottom ash; 460-500 parts of mineral powder; 35-45 parts of silica fume; 380-420 parts of fine quartz sand; 370-380 parts of activator; 15-17 parts of modifier; and 110-130 parts of steel fiber. The waste incineration bottom ash includes the following particle sizes and parts by weight: 35-45 parts of waste incineration bottom ash below 8μm; 75-85 parts of waste incineration bottom ash of 8-40μm; 150-170 parts of waste incineration bottom ash of 40-150μm; and 380-420 parts of waste incineration bottom ash of 150-500μm. The modifier includes the following raw materials in parts by weight: 3-5 parts of industrial-grade sodium gluconate with a content ≥98%; and 10-14 parts of quicklime powder with a content ≥95%.

2. The zero-clinker ultra-high performance concrete prepared using waste incineration bottom ash according to claim 1, characterized in that: The waste incineration bottom ash is obtained by grinding and classifying the raw bottom ash of municipal solid waste incineration into different particle sizes, and then fully mixing and homogenizing the bottom ash of different particle sizes.

3. The zero-clinker ultra-high performance concrete prepared using waste incineration bottom ash according to claim 1, characterized in that: The mineral powder is obtained by grinding granulated blast furnace slag to below 40μm.

4. The zero-clinker ultra-high performance concrete prepared using waste incineration bottom ash according to claim 1, characterized in that: The silica fume contains more than 95% SiO2 and has a particle size of less than 8μm.

5. The zero-clinker ultra-high performance concrete prepared using waste incineration bottom ash according to claim 1, characterized in that: The fine quartz sand has a particle size of 150-500 μm.

6. The zero-clinker ultra-high performance concrete prepared using waste incineration bottom ash according to claim 1, characterized in that: The activator comprises the following raw materials in parts by weight: 38-43 parts of industrial-grade sodium hydroxide with a content ≥90%; 230-235 parts of water glass with a modulus range of 3.41-3.60; and 95-105 parts of water.

7. The zero-clinker ultra-high performance concrete prepared using waste incineration bottom ash according to claim 1, characterized in that: The steel fiber has a length of 10 mm and a diameter of 0.12 mm.

8. A method for preparing zero-clinker ultra-high performance concrete based on the gradient grading method described in any one of claims 1-7 using waste incineration bottom ash, characterized in that: The preparation process includes the following steps: Step 1: Weigh out different particle sizes of waste incineration bottom ash, mineral powder, silica fume, fine quartz sand, activator, modifier, and steel fiber according to the formula; Step 2: Pour the weighed waste incineration bottom ash, mineral powder, silica fume, fine quartz sand, and modifier into a planetary mortar mixer and stir for 2-3 minutes to ensure uniform mixing; Step 3: Pour the activator into the mixture obtained in Step 2 and continue stirring for 3-5 minutes; Step 4: Pour the steel fiber into the mixture obtained in Step 3 and continue stirring for 2-3 minutes. After casting, molding, and curing, a graded, zero-clinker ultra-high performance concrete prepared using waste incineration bottom ash is obtained.

9. The method for preparing zero-clinker ultra-high performance concrete using waste incineration bottom ash according to claim 8, characterized in that: The preparation process of the activator is as follows: Sodium hydroxide, water glass and water are weighed according to the formula. Sodium hydroxide is dissolved in water and stirred thoroughly before being mixed with water glass. After thorough mixing, the mixture is sealed and allowed to stand. It is then cooled to room temperature to obtain the activator.

Images