Waste incineration bottom ash temperature-adjusting asphalt mixture as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of road engineering materials, and particularly relates to a waste incineration bottom ash temperature-adjusting asphalt mixture and a preparation method and application thereof.The waste incineration bottom ash temperature-adjusting asphalt mixture comprises mineral aggregate and asphalt, the mineral aggregate comprises waste incineration bottom ash, the mineral aggregate accounts for 94-96% of the weight of the raw materials, and the asphalt accounts for 2-3% of the weight of the raw materials. The asphalt accounts for 4-6% of the raw materials in parts by weight; the mineral aggregate is composed of aggregate, mineral powder filler and phase change microcapsules, and the waste incineration bottom ash comprises waste incineration bottom ash aggregate and waste incineration bottom ash powder; the aggregate and the mineral powder filler contain waste incineration bottom ash. According to the invention, the waste incineration bottom ash is adopted to replace mineral powder and fine aggregate in the mixture, so that the problems of difficulty in bottom ash treatment and shortage of natural aggregate can be solved, resource utilization of the household waste incineration bottom ash is realized, and the value of sustainable development is met; meanwhile, the porous structure of the bottom ash aggregate can also improve the water permeability of the asphalt road and provide certain sound absorption and noise reduction capabilities.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of road engineering materials, and particularly relates to a waste incineration bottom ash temperature-regulating asphalt mixture as well as a preparation method and application thereof. BACKGROUND

[0002] Municipal solid waste (MSW) is the general term for municipal solid waste. In recent years, with the rapid development of cities and the growth of population, the output of municipal solid waste has increased dramatically. These improperly treated wastes will have a huge impact on the ecological environment. Therefore, with the progress of green technology and green development concept in recent years, in addition to considering the traditional solid waste landfill method, people gradually regard it as a renewable resource and recycle it through a series of technologies, however, solid waste incineration will produce bottom ash (BA) and bottom ash with high heavy metal content, and the bottom ash accounts for about 80% of the combustion residues. Therefore, a large amount of bottom ash needs to be properly treated. Using bottom ash as raw material not only provides high-quality fine aggregate alternative materials for road engineering construction, saves natural aggregate resources, but also provides a solid waste digestion channel for turning waste into treasure, which has good economic and social benefits.

[0003] On the other hand, high temperature environment has a significant impact on the performance of asphalt pavement and urban heat island effect. For asphalt pavement, high temperature will cause the pavement to soften and reduce its stiffness, and under the continuous action of vehicle load and traffic flow, it is easy to cause pavement deformation, depression and wear and other problems. Once the critical temperature of the pavement is exceeded, the rut will develop rapidly, which will significantly reduce the service life of the pavement. At the same time, the rapid urbanization process aggravates the urban heat island effect, causing many negative effects: environmental quality decline, heat stress aggravation and frequent heat-related public health problems, and asphalt pavement, as a major component of urban surface, is also one of the key factors that aggravate the heat island effect.

[0004] At present, there are some patents that add phase change materials to asphalt to achieve a certain degree of temperature regulation capability, but the performance of asphalt is affected, and green development is not focused. In order to realize the rational utilization of resources and sustainable development of the environment, it is necessary to develop an asphalt mixture that uses solid waste raw materials and has a certain temperature regulation capability. SUMMARY

[0005] The present application aims to provide a waste incineration bottom ash temperature-regulating asphalt mixture as well as a preparation method and application thereof, and develop an asphalt mixture that uses solid waste raw materials and has a certain temperature regulation capability, which not only helps to improve the durability of the pavement, but also is an important way to handle solid waste accumulation and achieve sustainable development, which helps to realize the rational utilization of resources and sustainable development of the environment.

[0006] The purpose of the present application is achieved by the following technical solutions: The present application provides a kind of garbage incineration bottom ash temperature regulating asphalt mixture, the garbage incineration bottom ash temperature regulating asphalt mixture includes mineral aggregate and asphalt, the mineral aggregate includes garbage incineration bottom ash.

[0007] Further, the mineral aggregate accounts for 94-96% of the weight of the raw materials, and the asphalt accounts for 4-6% of the weight of the raw materials. The mineral aggregate is composed of aggregate, mineral powder filler and phase change microcapsule, the garbage incineration bottom ash includes garbage incineration bottom ash aggregate and garbage incineration bottom ash powder; the aggregate and mineral powder filler contain garbage incineration bottom ash.

[0008] Further, the aggregate includes coarse aggregate and fine aggregate; the fine aggregate contains garbage incineration bottom ash aggregate; the mineral powder filler contains garbage incineration bottom ash powder.

[0009] Further, the coarse aggregate, fine aggregate, mineral powder filler and phase change microcapsule account for 40-46%, 48-50%, 0-8% and 0-4% of the total weight of the mineral aggregate, respectively.

[0010] Further, the garbage incineration bottom ash powder accounts for 0-8% of the total weight of the mineral powder filler; and the garbage incineration bottom ash aggregate accounts for 0-20% of the total weight of the fine aggregate.

[0011] The present application also provides a preparation method of the garbage incineration bottom ash temperature regulating asphalt mixture, which comprises the following steps: (1) heat the asphalt to a liquid state, add SBS modifier, antioxidant and stabilizer, and then stand after shearing; (2) dry the garbage incineration bottom ash, grind the powder through a 100-mesh sieve, obtain the garbage incineration bottom ash aggregate by disc granulation method, and then heat and keep warm the coarse aggregate, garbage incineration bottom ash aggregate and powder; (3) melt the paraffin, mix with white carbon black in water bath to prepare the core material of microcapsule; then add plasticizer in organic solvent, stir, add powdered ethyl cellulose, stir again, take out and stand to obtain gel; mix the core material with the gel, dry, grind, sieve to obtain phase change microcapsule.

[0012] (4) add the phase change microcapsule into the heated coarse aggregate, fine aggregate and mineral powder filler, and then add the asphalt after stirring, stir again to obtain the bottom ash temperature regulating asphalt mixture.

[0013] Further, in step (2), the heating and keeping warm is heating to 120°C and keeping warm for 8h.

[0014] Further, in step (3), the phase change microcapsule contains paraffin 14-15 parts by weight, white carbon black 14-15 parts, ethyl cellulose 5.6-7 parts, plasticizer 14-16 parts, organic solvent 47-52.4 parts.

[0015] The application further provides application of the waste incineration bottom ash temperature-adjusting asphalt mixture in road construction.

[0016] Further, the waste incineration bottom ash temperature-adjusting asphalt mixture can consume construction waste and has temperature adjusting capacity.

[0017] The application has the following beneficial effects: 1. Since the application uses waste incineration bottom ash to replace mineral powder and fine aggregate in the mixture, the problem of bottom ash treatment difficulty and shortage of natural aggregate can be solved, the resource utilization of waste incineration bottom ash is realized, the value of sustainable development is met, and the porous structure of the bottom ash aggregate can improve the water permeability of the asphalt road and provide certain sound absorption and noise reduction capacity.

[0018] 2. In the application, the phase change material added in the asphalt mixture is in the form of phase change microcapsule, compared with the traditional impregnation method and direct addition method, the microcapsule can prevent the phase change material from leaking and affecting the road performance of the asphalt base, meanwhile, the microcapsule uses fumed silica as a carrier and paraffin as a phase change heat storage material, the fumed silica is a nanoscale material and has good adsorption performance, so that the fumed silica can coat and seal the paraffin in the process of heat absorption and phase change, so that the paraffin is not easy to leak, meanwhile, the particle size of the fumed silica is small, which can be uniformly dispersed in the asphalt and better combined with the asphalt pavement, so as to improve the durability and use performance of the road surface, meanwhile, the paraffin is low in price, so that the phase change microcapsule has good economic value, and the preparation process of the asphalt mixture is simple and the production cost is low.

[0019] 3. The waste incineration bottom ash temperature-adjusting asphalt mixture prepared by the preparation method of the application can give the asphalt mixture heat storage and temperature adjusting function relying on the latent heat characteristics of the phase change material, so as to reduce the maximum temperature of the road surface, delay the appearance time of the daily maximum temperature, and reduce the surface temperature of the road surface, so as to relieve the urban heat island effect and prolong the service life of the road surface. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed in the embodiments. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor.

[0021] Figure 1 A micrograph of the MPCM particles after drying and grinding in Example 1 of the present application; Figure 2 An effect verification graph of the bottom ash temperature regulating asphalt mixture prepared in Example 1 of the present application. DETAILED DESCRIPTION

[0022] The various illustrative embodiments of the present application will now be described in detail in connection with the accompanying drawings. This description is made for the purpose of demonstrating certain aspects of the present application and is not intended to limit the present application in any manner. Those skilled in the art will recognize that there are numerous variations of the illustrative embodiments described herein that are encompassed by the present application.

[0023] It should be understood that the terms used in the present application merely describe particular embodiments and are not intended to limit the present application. In addition, for numerical ranges in the present application, it should be understood that each intermediate value between the upper limit and the lower limit of the range is specifically disclosed. Each smaller range between any stated value or stated range and any other stated value or stated range is also encompassed within the present application. The upper and lower limits of these smaller ranges can be independently included or excluded from the range.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present application, preferred methods and materials are described. All documents mentioned herein are incorporated by reference to disclose and describe in full the methods and / or materials which are described therein. In the case of conflict between the present specification and any document incorporated herein by reference, the present specification will control.

[0025] Various modifications and changes can be made to the specific embodiments of the present application described herein without departing from the scope or spirit of the application. Other embodiments of the application will be apparent to those of ordinary skill in the art from the description and examples presented herein. The description and examples are illustrative of the application and are not intended to limit the scope of the application in any manner.

[0026] As used herein, the terms "comprise", "comprising", "include", "including", "have", "having" and the like are open-ended and do not exclude additional elements or steps.

[0027] The waste incineration bottom ash temperature regulating asphalt mixture prepared by the present application comprises the following raw materials by weight: 94-96% of mineral aggregates, and 4-6% of asphalt; The mineral aggregates are composed of aggregate, mineral powder filler and microencapsulated phase change material (MPCM); The aggregate includes coarse aggregate and fine aggregate; the coarse aggregate, the fine aggregate, the mineral powder filler and the MPCM account for 40-46%, 48-50%, 0-8% and 0-4% of the total weight of the mineral aggregates, respectively. The waste incineration bottom ash can replace part of the mineral powder filler or fine aggregate, wherein the waste incineration bottom ash aggregate replaces part of the fine aggregate, and the bottom ash powder replaces part of the mineral powder filler; The preparation method of the waste incineration bottom ash temperature-regulating asphalt mixture in the present application comprises the following steps: (1) First, heat the asphalt to 120 DEG C to a liquid state, then add SBS modifier, antioxidant and stabilizer, according to the weight fraction: 100 parts of base asphalt, 10-15 parts of SBS modifier, 1-5 parts of antioxidant, 1-2 parts of stabilizer, shear for 1-2 h, and wait for 1-2 h, while heating the coarse aggregate, the fine aggregate replaced by the waste incineration bottom ash aggregate part, the mineral powder replaced by the waste incineration bottom ash powder part, and the waste incineration bottom ash powder to 120 DEG C for 6-10 h.

[0028] (2) Put the heated aggregate, mineral powder and MPCM into a stirring pot and stir uniformly, then add the heated asphalt to prepare the bottom ash temperature-regulating asphalt mixture.

[0029] In the present application, the asphalt, aggregate, fine aggregate and mineral powder filler are mixed and stirred by using SMA-13, SMA-16, AC-20C, AC-25C or ATB-25 type gradation, and the hot or warm asphalt mixture mixing process is used.

[0030] It should be noted that the asphalt mixture is a conventional asphalt mixture known to those skilled in the art, mainly including asphalt, coarse aggregate, fine aggregate, mineral powder filler and additive (such as anti-stripping agent, anti-rutting agent, polymer modifier, etc.); The function of asphalt is to cement the loose granules together, and after tamping or compaction, it becomes an integral material with certain strength or is used to bond the pavement layers together, having the function of tack coat or prime coat; The coarse aggregate mainly plays a skeleton role; the fine aggregate plays a filling role; and the mineral powder also mainly plays a filling role, with a passing rate of 0.075 mm sieve hole being greater than 75%; The additive (such as anti-stripping agent, anti-rutting agent, polymer modifier, etc.) has the function of improving certain special properties of the asphalt mixture, such as the anti-stripping agent can improve the adhesion of asphalt and aggregate, and improve the water stability.

[0031] In the above technical solution, the waste incineration bottom ash powder replacing the mineral powder, according to the weight percentage, the waste incineration bottom ash powder accounts for 0-8% of the percentage of the mineral powder filler of the waste incineration bottom ash asphalt mixture, preferably 0-3%, the bottom ash particle size is less than 0.6 mm, preferably the content of the bottom ash particle size less than 0.15 mm is greater than 90%, and the content of the bottom ash particle size less than 0.075 mm is greater than 70%. The obtained waste incineration bottom ash temperature-regulating asphalt mixture can be applied to the surface layer or the base layer of the pavement.

[0032] The waste incineration bottom ash aggregate replacing fine aggregate in the above technical solution accounts for 0-20% of the mass percentage of fine aggregate, preferably 0-12%, and the preparation method is as follows: the collected bottom ash is dried and ground through a 100-mesh sieve, and the obtained bottom ash powder is granulated by a disc granulation method to obtain the waste incineration bottom ash aggregate. The aggregate is dried and replaces the fine aggregate in the asphalt mixture. Compared with direct landfill of bottom ash, the cementitious material can provide a certain strength to the granulated aggregate. At the same time, the bottom ash aggregate obtained by granulation has a porous lightweight structure, and when applied to road base, it not only improves the water permeability of the pavement, but also has the advantages of sound absorption and noise reduction.

[0033] The preparation method of the MPCM in the above technical solution is as follows: first, melt the paraffin at 60℃, weigh a certain amount of paraffin (Pa) and white carbon black (fumed silica) into a beaker in a 60℃ water bath and stir evenly, so that the white carbon black first physically adsorbs the Pa under normal pressure. Then move to a vacuum environment for full adsorption, so that the phase change material is completely adsorbed into the pores of the white carbon black to form the core material of the microcapsule. Secondly, weigh a certain proportion of anhydrous ethanol solution as an organic solvent in a beaker, then slowly add the calculated amount of plasticizer (diisooctyl sebacate), move to a magnetic stirrer and stir evenly, then slowly add the powdered ethyl cellulose to the mixed solution, continue to stir until the ethyl cellulose is completely dissolved, and the mixed solution becomes a light yellow transparent gel. After standing, mix the products obtained in the previous two steps according to the ratio, stir evenly, and place in an oven for drying (temperature: 60℃, time: 60-90 min). Grind the dried product gently, sieve and store, which is the prepared MPCM.

[0034] The above phase change microcapsule contains paraffin 14-15 parts, white carbon black 14-15 parts, ethyl cellulose 5.6-7 parts, plasticizer 14-16 parts, and organic solvent 47-52.4 parts by weight.

[0035] In the above technical solutions, paraffin wax has a wide melting temperature range and is often used in asphalt pavement temperature regulation. It does not undergo phase separation and can therefore be applied to asphalt and its mixtures. However, organic phase change materials have low thermal conductivity and suffer from defects such as liquid material leakage and volume expansion after melting. Therefore, they need to be encapsulated to prevent direct contact with asphalt and its impact on performance. Silica, among many carrier materials, has a large specific surface area, uniform pore size, good adsorption, and stable thermal and chemical properties. Therefore, this invention selects it as the carrier material, utilizing its porosity for adsorption. Silica is composed of a large number of spherical particles aggregated into small particle clusters. When these particles are treated with a solution of ethyl cellulose and diisooctyl sebacate, the intermolecular forces are enhanced, the particle size increases, and the surface becomes smoother after being encapsulated. Subsequently, the plasticizer diisooctyl sebacate is dissolved in anhydrous ethanol, and powdered film-forming material ethyl cellulose is slowly added to form a liquid-phase gelation system for the capsule wall material. The gelling system is mixed with the core material in a certain proportion, and the gelling system acts as a capsule wall material, uniformly coating the surface of the core material. Finally, by heating and evaporating the organic solvent, the gelled organic solvent is transformed into a thin film with a three-dimensional network structure, thereby forming stable microcapsules around the core material.

[0036] Example 1 The specific method for preparing the temperature-regulating asphalt mixture from waste incineration bottom ash in this embodiment is as follows: 1. Raw material selection It comprises 95% mineral aggregate and 5% bitumen by weight percentage, wherein the mineral aggregate consists of aggregate, mineral powder filler and MPCM; The mineral aggregate consists of 92% coarse aggregate and 3% mineral powder filler; the coarse aggregate consists of 43% coarse aggregate and 49% fine aggregate. 12% of the fine aggregate is replaced by waste incineration bottom ash aggregate; 3% of the mineral powder filler is replaced by waste incineration bottom ash powder; MPCM accounts for 4% of the total weight of the mineral aggregate. The bottom ash from the waste incineration plant comes from a waste incineration plant in Dongguan, and its composition is shown in Table 1 below.

[0037]

[0038] 2. Raw material specifications Waste incineration bottom ash powder: particle size <0.15mm (accounting for >90%), <0.075mm (accounting for >70%).

[0039] 3. Preparation method (1) Pretreatment Heat the asphalt to 120°C until it becomes liquid, add stabilizer (0.2% of asphalt mass), anti-stripping agent (0.3% of asphalt mass), and tackifier (0.1% of asphalt mass), and shear at high speed for 1.5 hours, then let it stand to develop for 1.5 hours.

[0040] (2) Preparation of bottom ash aggregate for waste incineration After the collected bottom ash is dried, it is ground and passed through a 100-mesh sieve. The resulting bottom ash powder is then processed by a disc granulation method to obtain waste incineration bottom ash aggregate. (3) Aggregate heating The coarse aggregate, waste incineration bottom ash aggregate, and powder are heated to 120°C and kept at that temperature for 8 hours.

[0041] (4) MPCM preparation The paraffin wax was melted at 60°C. The paraffin wax (Pa) and silica (fumed silica) were weighed and added to a beaker in a 60°C water bath and stirred evenly. The silica first physically adsorbed Pa under normal pressure. Then it was transferred to a vacuum environment for full adsorption, so that the phase change material was completely adsorbed into the pores of the silica, thus making the core material of the microcapsule. Weigh anhydrous ethanol solution into a beaker as the organic solvent, then slowly add the calculated mass of plasticizer (diisooctyl sebacate), transfer to a magnetic stirrer and stir evenly. Then slowly add powdered ethyl cellulose into the mixture and continue stirring until the ethyl cellulose is completely dissolved. After the mixture becomes a pale yellow transparent gel, remove it and let it stand. The products obtained in the first two steps are mixed according to the specified ratio, stirred thoroughly, and dried in an oven at 60°C for 80 minutes. The dried product is then ground, sieved, and stored to obtain the MPCM. A microscopic photograph of the finally obtained MPCM particles after drying and grinding is shown below. Figure 1 As shown.

[0042] In the above preparation process, MPCM contains, by weight, 15 parts paraffin, 14 parts silica, 5.6 parts ethyl cellulose, 14 parts plasticizer, and 47 parts organic solvent.

[0043] (5) Mixing and stirring The heated coarse aggregate, fine aggregate, mineral filler, and MPCM are put into a mixing pot and dry-mixed for 2 minutes until uniform. Then, modified asphalt is added and stirred at 120℃ and 1000rpm for 5 minutes. Then, it is allowed to stand at 120℃ for 0.5 hours to obtain the base gray temperature-regulating asphalt mixture.

[0044] Experimental Example 1 Two groups of asphalt mixtures were set up. One group was prepared by the process in Example 1, and the other group was a blank control asphalt group. The preparation steps were the same as those for temperature-adjusting asphalt. The difference was that the blank control group did not use incinerated bottom ash to replace fine aggregates and mineral powder.

[0045] Two sets of asphalt mixtures were mixed and poured into rut slabs, with temperature sensors embedded to read data. After demolding, the temperature-adjustable asphalt mixture and the blank control asphalt mixture specimens were buried in fine sand, with only the upper surface exposed. The temperature changes of the temperature-adjustable asphalt mixture and the blank control asphalt mixture specimens under sunlight were tested, and the results are as follows. Figure 2 As shown, by Figure 2 It can be seen that the maximum temperature difference is 5.3℃, which indicates that using this temperature-regulating asphalt mixture can effectively reduce the road surface temperature and alleviate the heat island effect.

[0046] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A temperature-regulating asphalt mixture for waste incineration bottom ash, characterized in that, The waste incineration bottom ash temperature-regulating asphalt mixture includes mineral aggregates and asphalt, wherein the mineral aggregates contain waste incineration bottom ash.

2. The waste incineration bottom ash temperature-regulating asphalt mixture as described in claim 1, characterized in that, The mineral material accounts for 94-96% of the raw material by weight, and the asphalt accounts for 4-6% of the raw material by weight. The mineral material is composed of aggregate, mineral powder filler and phase change microcapsules, and the waste incineration bottom ash includes waste incineration bottom ash aggregate and waste incineration bottom ash powder; the aggregate and mineral powder filler contain waste incineration bottom ash.

3. The waste incineration bottom ash temperature-regulating asphalt mixture as described in claim 2, characterized in that, The aggregates include coarse aggregates and fine aggregates; the fine aggregates include waste incineration bottom ash aggregates; the mineral powder filler includes waste incineration bottom ash powder.

4. The waste incineration bottom ash temperature-regulating asphalt mixture as described in claim 3, characterized in that, The coarse aggregate, fine aggregate, mineral powder filler, and phase change microcapsules account for 40-46%, 48-50%, 0-8%, and 0-4% of the total weight of the mineral material, respectively.

5. The waste incineration bottom ash temperature-regulating asphalt mixture as described in claim 3, characterized in that, The waste incineration bottom ash powder accounts for 0-8% of the total weight of the mineral powder filler; the waste incineration bottom ash aggregate accounts for 0-20% of the total weight of the fine aggregate.

6. The method for preparing the temperature-regulating asphalt mixture from waste incineration bottom ash as described in any one of claims 1-5, characterized in that, Includes the following steps: (1) Heat the asphalt to a liquid state, add SBS modifier, antioxidant and stabilizer, and let it stand after shearing; (2) The waste incineration bottom ash is dried and then ground and passed through a 100-mesh sieve. The resulting bottom ash powder is then granulated by a disc granulation method to obtain waste incineration bottom ash aggregate. The coarse aggregate, waste incineration bottom ash aggregate and powder are then heated and kept warm. (3) After melting paraffin, mix it with precipitated silica in a water bath to make the core material of the microcapsules; then add plasticizer to the organic solvent, stir and then add powdered ethyl cellulose, stir again and let stand to obtain gel; mix the core material and gel, dry, grind and sieve to obtain phase change microcapsules. (4) Stir the heated coarse aggregate, fine aggregate and mineral filler with the phase change microcapsules and add asphalt, stir again to obtain the bottom gray temperature-regulating asphalt mixture.

7. The preparation method according to claim 6, characterized in that, In step (2), the heating and heat preservation means heating to 120°C and then heat preservation for 8 hours.

8. The preparation method according to claim 6, characterized in that, In step (3), the phase change microcapsules contain, by weight, 14-15 parts paraffin, 14-15 parts silica, 5.6-7 parts ethyl cellulose, 14-16 parts plasticizer, and 47-52.4 parts organic solvent.

9. The application of the waste incineration bottom ash temperature-regulating asphalt mixture as described in any one of claims 1-5 in road construction.

10. The application as described in claim 9, characterized in that, The temperature-regulating asphalt mixture made from waste incineration bottom ash can consume construction waste and has temperature regulation capabilities.

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