Recycled aggregate energy-saving dry-mixed mortar and preparation method thereof

Abstract

The invention relates to the technical field of green building materials, in particular to recycled aggregate energy-saving dry-mixed mortar and a preparation method thereof, and the recycled aggregate energy-saving dry-mixed mortar is prepared from the following components in parts by mass: 65-85 parts of mineralized recycled aggregate; 18 to 28 parts of an enzymolysis seaweed gelatinizing agent; 8 to 15 parts of photo-thermal regulation and control microspheres; 10 to 18 parts of circuit board reinforcing powder; 4 to 9 parts of aerogel reinforced fiber; 10 to 17 parts of microbial flue gas desulfurization gypsum; 2-6 parts of a heavy metal chelate; 1.5 to 4 parts of self-repairing microcapsules; 12 to 22 parts of activated phosphogypsum powder; and 0.8-3 parts of a light response dispersant. Through the synergistic enhancement of the mineralized recycled aggregate and the photo-thermal regulation and control microspheres and the structural coupling design of the aerogel fibers and the heavy metal chelate, the synergistic improvement of the material performance and the environmental protection benefit is realized. The method is suitable for the field of novel building materials oriented to green buildings, ecological restoration engineering and circular economy, and the low-carbon and functional transformation of the building material industry is promoted.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of green building materials, in particular to a recycled aggregate energy-saving dry powder mortar and a preparation method thereof. BACKGROUND

[0002] As an important material for resource utilization of building demolition waste, recycled dry powder mortar has wide application requirements in the fields of green building, sponge city and existing building reconstruction. This type of mortar needs to meet the technical requirements of high strength, low energy consumption and environmental friendliness, and also needs to solve key problems such as removal of surface attachments of recycled aggregate, optimization of particle size distribution and energy saving of cementitious system. In the prior art, the processing of construction waste recycled aggregate and the performance regulation of mortar become core challenges, and it is required to develop a new preparation process with resource recycling rate and functional characteristics.

[0003] The existing solutions for this technical requirement mainly include the following: Mechanochemical activation method: the surface of recycled aggregate is modified by high-energy ball milling, which induces the expansion of micro-cracks and lattice distortion on the surface of the aggregate, thereby enhancing the physical adsorption capacity of the aggregate and the cementitious system.

[0004] Gas deposition coating technology: a nanoscale dense coating layer is formed on the surface of the recycled aggregate by plasma or chemical vapor deposition process, which reduces the water absorption rate and improves the reactivity. This scheme realizes the optimization of interface performance through molecular-level regulation.

[0005] Low-temperature sintering process: calcium aluminate minerals are added as auxiliary agents to promote the synergistic reaction of aggregate and cementitious materials at low temperature, thereby reducing heat consumption and carbon emissions.

[0006] Although the above schemes achieve the preparation of recycled dry powder mortar to some extent, there are still some deficiencies: Energy consumption and efficiency: the mechanical and chemical activation method has high energy consumption, which leads to high operating costs. Excessive crushing can damage the internal pore structure of the aggregate, thereby reducing its mechanical properties. This method has limited control over the particle size distribution of the aggregate, making it difficult to meet complex engineering requirements.

[0007] Insufficient process stability: the gas deposition coating technology relies on high-purity special gases and precise reaction devices, which have high equipment investment and maintenance costs. The bonding strength between the coating layer and the aggregate substrate is insufficient, and peeling may occur during long-term service.

[0008] Cost and feasibility limitations: the addition of calcium aluminate minerals in the low-temperature sintering process may cause abnormal hydration reactions in the later stage, leading to volume expansion and cracking of the mortar. Artificial intelligence algorithms rely on a large amount of high-precision experimental data, and the parameter prediction deviation is large under actual working conditions, affecting the stability of the process. SUMMARY

[0009] In view of the deficiencies of the prior art, the present application provides a recycled aggregate energy-saving dry powder mortar and a preparation method thereof, which solves the problems in the above background art.

[0010] According to a first aspect of the present application, a recycled aggregate energy-saving dry powder mortar is provided, which is composed of the following components in terms of mass fraction: Mineralized recycled aggregate: 65-85 parts; Enzymatic seaweed gelling agent: 18-28 parts; Photo-thermal regulation microspheres: 8-15 parts; Circuit board reinforcement powder: 10-18 parts; Aerogel reinforced fiber: 4-9 parts; Microbial desulfurization gypsum: 10-17 parts; Heavy metal chelate: 2-6 parts; Self-repairing microcapsules: 1.5-4 parts; Activated phosphogypsum powder: 12-22 parts; Light-responsive dispersant: 0.8-3 parts.

[0011] The mineralized recycled aggregate (MRA) is used to provide structural support and skeleton effect, and the compactness and interfacial adhesion of the aggregate are enhanced through mineralization treatment, thereby improving the overall mechanical properties of the mortar.

[0012] The circuit board reinforcement powder (PBRP) is used to enhance the compressive strength and electrical conductivity, and the metal oxides and glass fibers in the recycled electronic waste are compounded to form a nanoscale conductive path and optimize the particle size distribution. The metal phase can also react with the cement hydration products to form stable crystal phases, thereby improving long-term durability.

[0013] The heavy metal chelating agent (HMCA) is used to adsorb and fix heavy metal ions in the recycled aggregate, and a stable complex is formed through coordination bonds with harmful metals, thereby reducing the environmental leaching risk. Its high selective binding capacity can preferentially adsorb elements such as lead and cadmium which are highly toxic.

[0014] The self-healing microcapsules (SHMs) are used to realize the function of crack self-repairing, and the encapsulated repair agent is released at the crack site to react with the surrounding components to form fillers such as calcium carbonate. The toughness design of the microcapsule shell can withstand mechanical stress during construction and service.

[0015] According to the embodiment of the present application, the mineralized recycled aggregate is a hydrophobic porous particle obtained by crushing, screening, acid pickling, alkali etching and hydrophobic modification treatment of construction demolition concrete; the enzyme-degraded alginate gel is a gelling powder generated by the reaction of sodium alginate and protease; and the photo-thermal regulation microsphere is a core-shell structure microsphere with titanium dioxide as the carrier, internal filling of phase change paraffin and surface grafting of photosensitive polymer. The mass ratio of the sodium alginate to the protease is 1:1.5-1:2.5. The mass ratio of the titanium dioxide, the phase change paraffin and the photosensitive polymer is 1:0.5:0.1-1:0.8:0.3. The photosensitive polymer is a transparent gel polymer mixed by hydroxyethyl acrylate and acrylamide at a mass ratio of 1:1-1:2. The grafting rate of the photosensitive polymer is 15%-25%.

[0016] The enzyme-degraded alginate gel (EDAG) is used to improve the fluidity and early hydration activity of the gelling system. The sodium alginate is degraded by enzyme catalysis to form a porous network structure, promote water migration and ion diffusion, and delay the hydration reaction rate to avoid the risk of cracking caused by rapid setting.

[0017] The photo-thermal regulation microsphere (PTRM) is used to realize temperature response performance regulation. The light-heat material embedded in the microsphere absorbs external light energy and converts it into heat energy to dynamically adjust the hydration rate and hardening process inside the mortar. The controllable heat release characteristics can match the temperature and humidity conditions in different construction environments.

[0018] According to the embodiment of the present application, the ratio of sodium alginate to protease optimizes the molecular chain entanglement ability of the gelling agent, and the grafting rate of the photosensitive polymer precisely controls the heat response efficiency, so that the material maintains an appropriate hardening speed under different environmental temperatures, and finally realizes the synergistic improvement of structural strength and environmental adaptability.

[0019] According to the embodiment of the present application, the circuit board reinforced powder is a metal oxide composite powder obtained by centrifugal granulation of waste circuit boards after high-temperature melting at 1200-1400℃; the aerogel reinforced fiber is a porous fiber bundle composed of silica aerogel and aramid fiber; and the microbial desulfurization gypsum is a flaky gelling material obtained by modification treatment of industrial desulfurization gypsum by Sulfur Oxidizing Bacteria; The mass ratio of the silica aerogel to the aramid fiber is 1:1-1:3. The silica aerogel is a three-dimensional nano-porous flocculus obtained by polycondensation of tetraethyl orthosilicate. The mass ratio of the industrial desulfurization gypsum to the S. oxidans is 1:0.5-1:1.5.

[0020] Aerogel reinforcement fiber (ARF) is used to improve thermal insulation performance and crack resistance, and the porous structure of aerogel reduces the thermal conductivity, and the fiber bridging effect inhibits the expansion of microcracks. The light weight property can also reduce the overall density of the mortar, meeting the control requirements of energy-saving buildings on self-weight.

[0021] Microbial desulfurization gypsum (MDG) is used to adjust the pH value and stabilize the sulfate content, and through the metabolic process of microorganisms, the soluble sulfate is converted into an inert mineral phase to prevent swelling damage in the later period and improve the environmental performance of the material.

[0022] According to the embodiment of the application, the single fiber diameter of the aerogel reinforcement fiber is 8-15 μm, the particle size is 50-200 nm, and the porosity is 80-90%.

[0023] According to the embodiment of the application, the heavy metal chelate is a chelate particle formed by mixing ethylenediaminetetraacetic acid and nano iron oxide; the self-repairing microcapsule is a two-phase microcapsule formed by polyurethane coating calcium carbonate crystals; the activated phosphogypsum powder is an ultra-fine powder formed by microwave irradiation and activation treatment of phosphogypsum for 15-25 minutes; and the photo-responsive dispersant is a temperature-sensitive dispersion liquid formed by grafting isopropyl acrylamide on lignosulfonate. The mass ratio of the ethylenediaminetetraacetic acid to the nano iron oxide is 1:1-1:2. The mass ratio of the polyurethane to the calcium carbonate crystal is 4:1-9:1. The mass ratio of the lignosulfonate to the isopropyl acrylamide is 1:0.8-1:1.2.

[0024] Activated phosphogypsum powder (APP) is used to replace traditional cement to reduce carbon emissions, and the crystal structure of phosphogypsum is broken through chemical activation to improve the activity of the activated product participating in the hydration reaction. The activated product can cooperate with aluminate to generate high-strength hydrated calcium silicate phase.

[0025] Photo-responsive dispersant (PRD) is used to optimize the dispersibility and workability of components, and the conformation change of the molecular chain under light adjusts the surface tension to avoid particle agglomeration. The dynamic response characteristics can adapt to the construction scene requirements under different light conditions.

[0026] According to the embodiment of the present application, the lattice defects of the activated phosphogypsum powder increase after microwave irradiation, and a temperature-sensitive network is formed by grafting isopropyl acrylamide onto the lignosulfonate in the light-responsive dispersant, the conformation change of the dispersant adjusts the particle dispersity, meanwhile, the lignosulfonate is complexed with the sulfate ions in the phosphogypsum, thereby inhibiting the precipitation of harmful salts, and finally realizing the multiple synergistic effects of heavy metal solidification, crack self-repair and stable dispersion of components.

[0027] According to the second aspect of the present application, a preparation method of the recycled aggregate energy-saving dry powder mortar is provided, as shown in the specification, comprising the following steps: Figure 1 S1: preparing the mineralized recycled aggregate; S2: mixing the enzymatic seaweed gelling agent, the photo-thermal regulation microspheres and the circuit board reinforced powder in a light-proof ball mill to prepare a light-responsive substrate; S3: directionally dispersing the aerogel reinforcing fibers and the heavy metal chelate in a magnetic field to prepare a composite reinforcing body; S4: biomineralizing the self-repairing microcapsules and the microbial desulfurized gypsum to prepare a repair functional component; S5: mixing the mineralized recycled aggregate, the light-responsive substrate, the composite reinforcing body, the repair functional component and the activated phosphogypsum powder to prepare a premix; S6: adding the light-responsive dispersant to the premix and performing gradient temperature blending to prepare a mortar mixture; S7: performing light-triggered forming and biological curing on the mortar mixture to prepare the recycled aggregate energy-saving dry powder mortar. According to the embodiment of the present application, the preparation of the mineralized recycled aggregate comprises:

[0028] putting the building demolition concrete into a jaw crusher with a rotation speed of 200-300 rpm, and after crushing for 1-2 hours, the recycled aggregate particles with a particle size of 5-10 mm are selected by a vibrating screen; immersing the recycled aggregate particles in a hydrochloric acid solution with a concentration of 10-15 wt% for acid pickling for 30-60 minutes to obtain initial activated particles, wherein the mass ratio of the recycled aggregate particles to the hydrochloric acid solution is 1:5-1:8; immersing the initial activated particles in a sodium hydroxide solution with a concentration of 5-8 wt% for alkali etching for 20-40 minutes to obtain activated aggregate, wherein the mass ratio of the initial activated particles to the sodium hydroxide solution is 1:4-1:6; immersing the initial activated particles in a sodium hydroxide solution with a concentration of 5-8 wt% for alkali etching for 20-40 minutes to obtain activated aggregate, wherein the mass ratio of the initial activated particles to the sodium hydroxide solution is 1:4-1:6; The activated aggregate is washed by ultrasonic pure water, and then is put into a fluidized bed reactor with a gas flow rate of 1-2 m / s and a temperature of 150-200 DEG C, and is steamed by inputting silane coupling agent for 30-60 minutes to prepare the mineralized recycled aggregate, wherein the mass ratio of the activated aggregate to the silane coupling agent is 1:0.5-1:1.

[0029] According to the embodiment of the present application, the mineralized recycled aggregate is adjusted in particle size by a crushing and screening process, the surface is activated by acid washing and alkali etching, and a hydrophobic layer is constructed by silane coupling agent grafting, so that the interface adhesion and long-term durability are synergistically enhanced.

[0030] According to the embodiment of the present application, the aerogel reinforcing fiber and the heavy metal chelate are dispersed in a magnetic field to prepare a composite reinforcing body, which comprises: The aerogel reinforcing fiber and the heavy metal chelate are added into a magnetic field stirrer in a mass ratio of 1:1-1:2, and are stirred at a speed of 500-800 rpm for 30-60 minutes to obtain a basic mixture. The basic mixture is placed in an alternating magnetic field of 0.5-1 T, and is heated to 80-90 DEG C at a heating rate of 3-5 DEG C / min, and is magnetically stirred for 20-40 minutes to prepare the composite reinforcing body.

[0031] According to the embodiment of the present application, the magnetic field stirring makes the aerogel fibers arrange along the magnetic force lines to form a continuous reinforcing network, and the heavy metal chelate is uniformly dispersed in the fiber gap due to the response of the magnetic particles to the magnetic field, and the two form a composite interface through physical winding and chemical adsorption. Finally, a composite reinforcing body with structural reinforcement and pollutant adsorption capacity is formed.

[0032] According to the embodiment of the present application, the self-repairing microcapsule and the microbial desulfurization gypsum are subjected to a biological mineralization treatment to prepare a repair functional component, which comprises: The microbial desulfurization gypsum and deionized water are mixed in a mass ratio of 1:0.3-1:0.5 to prepare a mixed slurry. The self-repairing microcapsule and the mixed slurry are put into a biological mineralization reactor in a mass ratio of 1:1-1:2, and are oscillated at a temperature of 25-30 DEG C and a pH value of 7-8 for 30-60 minutes to prepare the repair functional component.

[0033] According to the embodiment of the present application, the self-repairing microcapsule and the microbial desulfurization gypsum synergistically enhance the repair function through biological mineralization, the microbial metabolites and the repair agent released from the microcapsule jointly form a stable crystalline network to seal cracks and regulate the sulfate phase, the reaction efficiency is accurately controlled under the environmental conditions, and the synergistic effect of physical and chemical repair is realized.

[0034] According to the embodiment of the present application, the mortar mixture is prepared by adding the light-responsive dispersant to the premix and then performing gradient temperature blending, which comprises: The premix and the light-responsive dispersant are added to a planetary mixer in a mass ratio of 100:0.8-100:3, and then blended according to a gradient temperature method, wherein the gradient temperature method comprises: First gradient: 50-60℃, mixing for 30-35 minutes; Second gradient: 100-110℃, mixing for 20-25 minutes; Third gradient: 150-160℃, mixing for 10-15 minutes.

[0035] According to the embodiment of the present application, the mortar mixture is prepared by gradient temperature blending to realize the synergistic effect of components. In the low-temperature stage, the light-responsive dispersant is preliminarily penetrated and the surface tension is reduced. In the medium-temperature stage, the molecular-level entanglement of the dispersant and the premix is promoted. In the high-temperature stage, the particle coating and structure stabilization are completed. The gradient temperature strategy takes into account the thermodynamic and kinetic equilibrium, which avoids the inactivation of components caused by local overheating and ensures sufficient contact between interfaces, thereby improving the rheological properties and component stability of the mortar mixture.

[0036] According to the embodiment of the present application, the mortar mixture is subjected to light-triggered shaping and biological curing to prepare the recycled aggregate energy-saving dry powder mortar, which comprises: The mortar mixture is loaded into a photocuring mold, and irradiated for 10-20 minutes under the conditions of a wavelength of 500-600nm and an irradiation intensity of 100-200W / m² to prepare a light-triggered cementing material. The light-triggered cementing material is placed in a biological curing box and cultured for 7-14 days under the conditions of a temperature of 20-30℃ and a humidity of 70-80% to prepare the recycled aggregate energy-saving dry powder mortar.

[0037] According to the embodiment of the present application, the ordered structure provided by photocuring provides a template for ion transmission and crystal growth in biological curing, and the mineral phases such as calcium carbonate generated in biological curing further strengthen the interface bonding. The two together realize the gradient optimization of mechanical properties and durability, and finally form a recycled aggregate energy-saving dry powder mortar with rapid shaping ability and long-term stability.

[0038] The present application has the following advantages: The present application selects renewable raw materials, significantly improves the sustainability and resource recycling rate of the material. The mineralized recycled aggregate is treated by multi-step chemical modification of building demolition waste, realizing efficient recycling of waste concrete. The circuit board reinforced powder is obtained by high-temperature melting recovery of electronic waste, which converts industrial solid waste into high-value-added materials. Each component in the raw material system has renewable or recyclable characteristics, greatly reducing the dependence on primary resources, while reducing the environmental burden of building waste landfill, in line with the core concept of circular economy and low-carbon development.

[0039] The present application realizes significant optimization of performance through multi-dimensional synergy between raw materials. The hydrophobic porous structure of the mineralized recycled aggregate matches the porous network of the enzymatic seaweed gelling agent, forming a stable interfacial bonding system and improving the overall mechanical properties. The photothermal control microspheres dynamically adjust the hydration reaction rate through temperature response mechanism, and cooperate with the heat insulation characteristics of aerogel reinforced fibers to ensure the service stability of the material in complex environments. The self-repairing microcapsules and the biomineralization of microbial desulfurization gypsum are synchronized to extend the service life of the material.

[0040] The present application ensures the controllability and consistency of material performance through systematic innovation of the preparation process. The gradient temperature blending strategy combines the dynamic regulation ability of the light-responsive dispersant to precisely match the dispersion needs of components at different temperature stages, avoiding agglomeration. The magnetic field directional dispersion technology enhances the spatial distribution uniformity of aerogel reinforced fibers and heavy metal chelates, improving the reinforcement effect. The synergistic application of biomineralization treatment and light-triggered molding forms a highly dense gel network. The whole-process process design takes into account efficiency and quality, laying the foundation for large-scale production.

[0041] The present application expands the application boundary of the material through the integrated design of multi-functional properties. The photothermal control microspheres endow the material with environmental adaptability, enabling it to maintain stable performance in temperature fluctuation scenarios. The synergistic effect of heavy metal chelates and microbial desulfurization gypsum effectively solves the heavy metal leaching risk in recycled aggregate, improving the environmental safety of the material. The combination of activated phosphogypsum powder and light-responsive dispersant not only reduces carbon emissions but also improves workability. The superposition of multi-dimensional properties makes the mortar suitable for high durability requirements of building structures, ecological restoration engineering and special scenarios in extreme environments.

[0042] The present application constructs a new building material system integrating environmental protection, economy and functionality. The green design of raw material selection and preparation process significantly reduces carbon emission intensity compared with traditional mortar, while achieving a substantial increase in the resource utilization rate of construction waste. The synergistic effect of multifunctional components significantly improves the service life of the material and reduces the whole life cycle maintenance cost. The scalable process route ensures the feasibility of industrialization of the technical achievements. The mortar has wide application value in the fields of green building, sponge city and infrastructure renewal, and provides key technical support for sustainable development.

[0043] Of course, implementing any product of the present application does not necessarily require achieving all the advantages described above at the same time. BRIEF DESCRIPTION OF DRAWINGS

[0044] Figure 1 The preparation method flowchart of the embodiment of the present application. DETAILED DESCRIPTION

[0045] The embodiment of the present application proposes a recycled aggregate energy-saving dry powder mortar and a preparation method thereof.

[0046] Example 1: Standard formula recycled aggregate energy-saving dry powder mortar

[0047] Mineralized recycled aggregate: 75 parts; Enzymatic seaweed gelling agent: 23 parts; Light-heat regulated microspheres: 12 parts; Circuit board strengthening powder: 14 parts; Aerogel reinforcing fiber: 7 parts; Microbial desulfurization gypsum: 14 parts; Heavy metal chelate: 4 parts; Self-repairing microcapsule: 2.8 parts; Activated phosphogypsum powder: 17 parts; Light-responsive dispersant: 2 parts.

[0048] Example 2: Increase the content of mineralized recycled aggregate

[0049] Mineralized recycled aggregate: 85 parts; Enzymatic seaweed gelling agent: 23 parts; Light-heat regulated microspheres: 8 parts; Circuit board strengthening powder: 14 parts; Aerogel reinforcing fiber: 7 parts; Microbial desulfurization gypsum: 14 parts; Heavy metal chelate: 4 parts; Self-repairing microcapsule: 2.8 parts; Activated phosphogypsum powder: 17 parts; Light-responsive dispersant: 2 parts.

[0050] Example 3: Reducing aerogel reinforcing fiber content

[0051] Mineralized recycled aggregate: 75 parts; Enzymatic seaweed gel binder: 23 parts; Photo-thermal regulating microspheres: 12 parts; Circuit board strengthening powder: 14 parts; Aerogel reinforcing fiber: 4 parts; Microbial desulfurization gypsum: 14 parts; Heavy metal chelate: 4 parts; Self-repairing microcapsule: 2.8 parts; Activated phosphogypsum powder: 17 parts; Photo-responsive dispersant: 2 parts.

[0052] Example 4: Enhancing antibacterial performance Mineralized recycled aggregate: 75 parts; Enzymatic seaweed gel binder: 23 parts; Photo-thermal regulating microspheres: 12 parts; Circuit board strengthening powder: 14 parts; Aerogel reinforcing fiber: 7 parts; Microbial desulfurization gypsum: 14 parts; Heavy metal chelate: 6 parts; Self-repairing microcapsule: 4 parts; Activated phosphogypsum powder: 17 parts; Photo-responsive dispersant: 2 parts.

[0053] Example 5: Optimizing biocompatibility Mineralized recycled aggregate: 75 parts; Enzymatic seaweed gel binder: 28 parts; Photo-thermal regulating microspheres: 12 parts; Circuit board strengthening powder: 14 parts; Aerogel reinforcing fiber: 7 parts; Microbial desulfurization gypsum: 17 parts; Heavy metal chelate: 2 parts; Self-repairing microcapsule: 1.5 parts; Activated phosphogypsum powder: 12 parts; Photo-responsive dispersant: 2 parts.

[0054] Example 6: Improving mechanical strength

[0055] Mineralized recycled aggregate: 75 parts; Enzymatic seaweed gel binder: 23 parts; Photo-thermal regulating microspheres: 15 parts; Circuit board strengthening powder: 18 parts; Aerogel-reinforced fibers: 9 parts; Microbial desulfurization gypsum: 14 parts; Heavy metal chelates: 4 parts; Self-healing microcapsules: 4 portions; Activated phosphogypsum powder: 22 parts; Photoresponsive dispersant: 3 parts.

[0056] Comparative Example 1: Microbial-free desulfurized gypsum

[0057] Mineralized recycled aggregate: 75 parts; Enzymatic hydrolysis of seaweed gelling agent: 23 parts; Photothermal-controlled microspheres: 12 parts; Circuit board reinforcing powder: 14 parts; Aerogel-reinforced fiber: 7 parts; Heavy metal chelates: 4 parts; Self-healing microcapsules: 2.8 portions; Activated phosphogypsum powder: 17 parts; Photoresponsive dispersant: 2 parts.

[0058] Comparative Example 2: Microspheres without photothermal regulation

[0059] Mineralized recycled aggregate: 75 parts; Enzymatic hydrolysis of seaweed gelling agent: 23 parts; Circuit board reinforcing powder: 14 parts; Aerogel-reinforced fiber: 7 parts; Microbial desulfurization gypsum: 14 parts; Heavy metal chelates: 4 parts; Self-healing microcapsules: 2.8 portions; Activated phosphogypsum powder: 17 parts; Photoresponsive dispersant: 2 parts.

[0060] Comparative Example 3: Aerogel-free reinforced fibers

[0061] Mineralized recycled aggregate: 75 parts; Enzymatic hydrolysis of seaweed gelling agent: 23 parts; Photothermal-controlled microspheres: 12 parts; Circuit board reinforcing powder: 14 parts; Microbial desulfurization gypsum: 14 parts; Heavy metal chelates: 4 parts; Self-healing microcapsules: 2.8 portions; Activated phosphogypsum powder: 17 parts; Photoresponsive dispersant: 2 parts.

[0062] Comparative Example 4: No photoresponsive dispersant

[0063] Mineralized recycled aggregate: 75 parts; Enzymatic seaweed gelatinizer: 23 parts; Photo-thermal regulation microspheres: 12 parts; Circuit board strengthening powder: 14 parts; Aerogel reinforced fiber: 7 parts; Microbial desulfurization gypsum: 14 parts; Heavy metal chelate: 4 parts; Self-repairing microcapsule: 2.8 parts; Activated phosphogypsum powder: 17 parts.

[0064] Experimental examples: The performance of Examples 1-6 and Comparative Examples 1-4 was determined based on the above, and the results are shown in Table 1. This includes: 1. Compressive strength test A compressive strength test was performed on the mortar test piece using a pressure testing machine at a rate of 10 mm / min, and the peak load at the time of failure was recorded.

[0065] 2. Water resistance test The mortar test piece was immersed in distilled water for 28 days, and the mass change rate was measured every 7 days to calculate the water absorption rate and strength retention rate.

[0066] 3. Heavy metal leaching rate test The leaching concentration of heavy metals such as lead, cadmium, and chromium in the mortar was determined by atomic absorption spectrometry to evaluate environmental safety.

[0067] 4. Construction fluidity test The flow spread of the mortar was measured using a slump flow meter to evaluate the workability of the mortar.

[0068] 5. Self-repairing efficiency test After pre-setting artificial cracks on the surface of the test piece and curing for 7 days, the crack closure rate and the compressive strength recovery rate after repair were measured.

[0069] 6. Thermal conductivity test The thermal conductivity of the mortar was measured using a laser flash method to evaluate its thermal insulation performance.

[0070] Table 1. Experimental data of Examples 1-6 and Comparative Examples 1-4 of the present application

[0071] As can be seen from Table 1, the compressive strength: Example 6 showed the best compressive performance due to the simultaneous increase in the content of photo-thermal regulation microspheres, circuit board strengthening powder, and activated phosphogypsum powder, forming a dense gel network. Comparative Example 2 had the lowest strength due to the absence of photo-thermal regulation microspheres, resulting in a loose structure.

[0072] Water resistance: Example 5 significantly reduces porosity and harmful ion precipitation by optimizing the ratio of enzymatic seaweed gelling agent and microbial desulfurized gypsum, and has the best water resistance; Comparative Example 1 has increased water absorption rate due to the absence of microbial desulfurized gypsum.

[0073] Heavy metal leaching rate: Example 4 achieves efficient adsorption and solidification by increasing the synergistic effect of heavy metal chelate and self-repairing microcapsules, and has the lowest leaching rate; Comparative Example 2 has serious heavy metal release due to the lack of chelation mechanism.

[0074] Construction fluidity: Example 3 has the best fluidity due to improved particle dispersion by reducing the content of aerogel reinforcing fibers; Example 6 has a significant decrease in fluidity due to a large proportion of high-density components.

[0075] Self-repairing efficiency: Example 4 has the highest crack closure rate by releasing calcium carbonate from self-repairing microcapsules and synchronously mineralizing microorganisms; Comparative Example 3 has insufficient repairability due to the absence of the bridging effect of aerogel reinforcing fibers.

[0076] Thermal conductivity: Example 5 has significantly reduced thermal conductivity due to a high proportion of aerogel reinforcing fibers and a porous structure; Comparative Example 2 has the highest thermal conductivity due to the absence of the thermal insulation layer of photothermal regulation microspheres.

[0077] Based on the above integrated experimental data, the regenerated aggregate energy-saving dry powder mortar proposed by the present application has outstanding performance in compressive strength, environmental adaptability and functional integration through multi-component synergistic design. The raw material selection takes into account resource recycling and environmental protection needs, and is suitable for green buildings, sponge cities and infrastructure repair scenarios. In the future, it can be further expanded to intelligent temperature control mortar, marine engineering protection materials and other fields, promoting the development of the construction industry towards low carbonization and functionalization.

[0078] Although the preferred embodiments of the present application have been described, those skilled in the art can make further changes and modifications to these embodiments once they understand the basic inventive concept. Therefore, the appended claims are intended to include the preferred embodiments and all changes and modifications falling within the scope of the present application.

[0079] Obviously, many modifications and variations of the present application are possible in light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims and their equivalents, the application can be practiced otherwise than as specifically described.

Claims

1. A recycled aggregate energy-saving dry powder mortar, characterized in that, It consists of the following components in parts by weight: Mineralized recycled aggregate: 65-85 parts; Enzymatic hydrolysis of seaweed gelling agent: 18-28 parts; Photothermal regulated microspheres: 8–15 parts; Circuit board reinforcing powder: 10-18 parts; Aerogel-reinforced fibers: 4–9 parts; Microbial desulfurization gypsum: 10-17 parts; Heavy metal chelates: 2-6 parts; Self-repairing microcapsules: 1.5–4 parts; Activated phosphogypsum powder: 12-22 parts; Photoresponsive dispersant: 0.8 to 3 parts.

2. The recycled aggregate energy-saving dry powder mortar according to claim 1, characterized in that: The mineralized recycled aggregate is hydrophobic porous particles obtained from demolished concrete after crushing, screening, acid washing, alkali etching and fluidized bed hydrophobic modification; the enzymatically hydrolyzed seaweed gelling agent is a gelling powder generated by the reaction of sodium alginate and protease; the photothermal regulated microspheres are core-shell structured microspheres formed by titanium dioxide as a carrier, filled with phase change paraffin wax and grafted with photosensitive polymer on the surface. The mass ratio of sodium alginate to protease is 1:1.5 to 1:2.

5. The mass ratio of the titanium dioxide, the phase change paraffin and the photosensitive polymer is 1:0.5:0.1-1:0.8:0.

3. The photosensitive polymer is a transparent gel-like polymer made by mixing hydroxyethyl acrylate and acrylamide in a mass ratio of 1:1-1:

2. The grafting rate of the photosensitive polymer is 15%-25%.

3. The recycled aggregate energy-saving dry powder mortar according to claim 1, characterized in that: The circuit board reinforcing powder is a metal oxide composite powder obtained by centrifugation after melting waste circuit boards at a high temperature of 1200-1400℃; the aerogel reinforcing fiber is a porous fiber bundle composed of silica aerogel and aramid fiber; the microbial desulfurization gypsum is a sheet-like cementitious material obtained by modifying industrial desulfurization gypsum with sulfur-oxidizing bacteria. The mass ratio of the silica aerogel to the aramid fiber is 1:1 to 1:3, and the silica aerogel is a three-dimensional nanoporous flocculent formed by the condensation of tetraethyl orthosilicate. The mass ratio of the industrial desulfurized gypsum to the sulfur-oxidizing bacteria is 1:0.5-1:1.

5.

4. The recycled aggregate energy-saving dry powder mortar according to claim 1, characterized in that: The heavy metal chelate is a chelating agent particle composed of ethylenediaminetetraacetic acid and nano iron oxide; the self-healing microcapsule is a biphasic microcapsule formed by polyurethane coating calcium carbonate crystals; the activated phosphogypsum powder is an ultrafine powder formed by microwave radiation activation treatment of phosphogypsum for 15-25 minutes; the photoresponsive dispersant is a thermosensitive dispersion generated by grafting lignin sulfonate with isopropyl acrylamide. The mass ratio of the ethylenediaminetetraacetic acid to the nano-iron oxide is 1:1 to 1:

2. The mass ratio of the polyurethane to the calcium carbonate crystals is 4:1-9:1; The mass ratio of the lignin sulfonate to the isopropyl acrylamide is 1:0.8-1:1.

2.

5. A method for preparing recycled aggregate energy-saving dry powder mortar according to any one of claims 1-4, characterized in that: Includes the following steps: Preparation of the mineralized recycled aggregate; The enzymatically hydrolyzed seaweed gelling agent, the photothermal regulated microspheres, and the circuit board reinforcing powder were mixed by ball milling in the dark to prepare a photoresponsive substrate. The aerogel-reinforced fibers and the heavy metal chelate are directionally dispersed in a magnetic field to prepare a composite reinforcement. The self-healing microcapsules were biomineralized with the microbial desulfurized gypsum to prepare a repair functional component. The mineralized recycled aggregate, the photoresponsive substrate, the composite reinforcement, the repair functional component, and the activated phosphogypsum powder are mixed to prepare a premix. After adding the photoresponsive dispersant to the premix, gradient heating and blending are performed to prepare mortar mixture; The mortar mixture is subjected to photo-triggered molding and biological curing to prepare the recycled aggregate energy-saving dry powder mortar.

6. The preparation method according to claim 5, characterized in that: The preparation of the mineralized recycled aggregate includes: The concrete from the demolished building is fed into a jaw crusher with a rotation speed of 200-300 rpm. After crushing for 1-2 hours, recycled aggregate particles with a particle size of 5-10 mm are selected by vibrating screen. The recycled aggregate particles are immersed in a hydrochloric acid solution with a concentration of 10-15wt% for 30-60 minutes to obtain initially activated particles, wherein the mass ratio of the recycled aggregate particles to the hydrochloric acid solution is 1:5-1:

8. The initial activated particles are immersed in a sodium hydroxide solution with a concentration of 5-8 wt% for alkali etching for 20-40 minutes to obtain activated aggregate, wherein the mass ratio of the initial activated particles to the sodium hydroxide solution is 1:4-1:

6. The activated aggregate is ultrasonically washed with pure water and then placed in a fluidized bed reactor with a gas flow rate of 1-2 m / s and a temperature of 150-200℃. A silane coupling agent is then introduced and steamed for 30-60 minutes to prepare the mineralized recycled aggregate. The mass ratio of the activated aggregate to the silane coupling agent is 1:0.5-1:

1.

7. The preparation method according to claim 5, characterized in that: The step of directionally dispersing the aerogel-reinforcing fibers and the heavy metal chelate in a magnetic field to prepare the composite reinforcement includes: The aerogel reinforcing fiber and the heavy metal chelate were added to a magnetic stirrer at a mass ratio of 1:1 to 1:2 and stirred at 500-800 rpm for 30-60 minutes to obtain the basic mixture. The base mixture is placed in an alternating magnetic field of 0.5-1T and heated to 80-90℃ at a heating rate of 3-5℃ / min. The mixture is then magnetically stirred for 20-40 minutes to prepare the composite reinforcement.

8. The preparation method according to claim 5, characterized in that: The step of biomineralizing the self-healing microcapsules with the microbial desulfurized gypsum to prepare the repair functional components includes: The microbial desulfurization gypsum was mixed with deionized water at a mass ratio of 1:0.3-1:0.5 to prepare a mixed slurry; The self-healing microcapsules and the mixed slurry were added into a biomineralization reactor at a mass ratio of 1:1 to 1:2, and shaken for 30 to 60 minutes at a temperature of 25-30°C and a pH of 7-8 to prepare the repair functional component.

9. The preparation method according to claim 5, characterized in that: The step of adding the photoresponsive dispersant to the premix and then performing gradient temperature mixing to prepare the mortar mixture includes: The premix and the photoresponsive dispersant are added to a planetary mixer at a mass ratio of 100:0.8-100:3, and then blended according to a gradient temperature method to prepare the mortar mixture. The gradient temperature method includes: First gradient: 50-60℃, mix for 30-35 minutes; Second gradient: 100-110℃, mix for 20-25 minutes; Third gradient: 150-160℃, mix for 10-15 minutes.

10. The preparation method according to claim 5, characterized in that: The process of performing photo-triggered molding and biological curing on the mortar mixture to prepare the recycled aggregate energy-saving dry powder mortar includes: The mortar mixture is loaded into a photocuring mold and irradiated for 10-20 minutes under conditions of wavelength of 500-600nm and light irradiation intensity of 100-200W / m² to prepare a phototriggered gel. The phototriggered gel is placed in a biological curing chamber and cultured for 7-14 days at a temperature of 20-30℃ and a humidity of 70-80% to prepare the recycled aggregate energy-saving dry powder mortar.

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