CN112645668A - Steam-curing-free precast concrete and preparation method thereof - Google Patents
Steam-curing-free precast concrete and preparation method thereof Download PDFInfo
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
- C04B28/02—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing hydraulic cements other than calcium sulfates
- C04B28/06—Aluminous cements
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
- C04B2111/20—Resistance against chemical, physical or biological attack
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
- C04B2111/34—Non-shrinking or non-cracking materials
- C04B2111/343—Crack resistant materials
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2201/00—Mortars, concrete or artificial stone characterised by specific physical values
- C04B2201/50—Mortars, concrete or artificial stone characterised by specific physical values for the mechanical strength
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Abstract
The steam-curing-free precast concrete and the preparation method thereof are characterized in that the concrete is prepared from the following raw materials: 360-380 kg of ordinary portland cement, 10-20 kg of sulphoaluminate cement, 30-50 kg of composite admixture, 600-650 kg of sand, 1150-1200 kg of stones, 130-140 kg of water, 3-5 kg of high-performance water reducing agent, 10-20 kg of nano C-A-S-H namely aluminum-doped hydrated calcium silicate suspension, 5-8 kg of nano silica sol, 2-5 kg of composite early strength agent and 0.5-1 kg of exciting agent. When the concrete is prepared, the ordinary portland cement, the sulphoaluminate cement, the composite admixture, the sand and the stones are poured into a stirrer to be dry-mixed, and then the rest raw materials are sequentially added into the stirrer. The preparation method of the precast concrete is simple, the precast concrete can be naturally cured for 8h without adopting high-temperature steam curing, the form removal strength exceeds 22MPa, the durability of the precast concrete is improved, the energy consumption is saved, and the turnover efficiency of the mould is improved.
Description
Technical Field
The invention relates to a steam curing-free precast concrete, belongs to the field of building materials, and further relates to a preparation method of the steam curing-free precast concrete.
Background
Because the assembly type building has the characteristics of energy conservation, environmental protection and the like, the country highly attaches importance to the development of the assembly type building. In 2016, the national 'guidance suggestion about the vigorous development of the fabricated building' is provided, and the time for competing for about 10 years of force is definitely provided, so that the fabricated building accounts for 30 percent of the area of the newly built building. The precast concrete used as the main body of the fabricated building comprises precast concrete products such as subway segments, overhead segment bridge members, high-speed rail plates, drain pipe and water delivery pipes, building wallboards, floor slabs, beam column members and the like.
The precast concrete member no matter is a structure or an appearance, the precast concrete member needs to reach a higher standard, and a shaping steel mould is generally needed to be used as a mould during manufacturing so as to realize perfect splicing of all precast members. In order to improve production efficiency, accelerate mold turnover, minimize construction period, and maximize benefit, precast concrete requires a higher level of early strength. Taking a common subway segment precast concrete product as an example, the production process firstly needs the concrete to have good working performance, and requires the concrete to have good thixotropy, easy vibration and good appearance; secondly, the concrete is required to be coagulated in a short time, so that surface finishing and plastering are finished; finally, the lifting and demolding strength of the concrete is required to be more than 15MPa in about 7-8 hours. Steam curing is a common means for realizing the technical requirement, the general curing temperature is 60 ℃, and the curing process comprises four stages of standing, heating, constant temperature and cooling. However, the steam curing process not only has large energy consumption, high cost and environmental pollution, but also has the prominent problems of large brittleness, insufficient durability and the like of the concrete cured at high temperature. Steam curing can affect the development of later strength of concrete, and precast concrete members are easy to crack, thereby affecting the development and application of precast concrete products. The method has important significance in reducing the steam curing time as much as possible and even improving the early strength in a steam curing-free mode in the face of the series of problems.
In order to realize the purpose of early strength and steam curing free of precast concrete, the traditional technology comprises the following steps: reducing the water-to-gel ratio, increasing the cement consumption, and adding superfine mineral admixtures such as silica fume. However, the addition of the ultrafine mineral admixture often increases the self-shrinkage of concrete, the increase of the cement dosage by reducing the water-cement ratio also causes the problems of the increase of the concrete viscosity, the increase of the compaction difficulty of vibration and the like, and the appearance defect is easily caused. Therefore, the concrete admixture needs to be realized with the help of modern concrete admixtures, which comprise polycarboxylic acid water reducing agents and various inorganic or organic early strength agents. Because the polycarboxylic acid water reducing agent is difficult to exert the optimal early strength performance at low temperature, various inorganic or organic early strength agents are often required to be added into concrete during winter construction. However, single inorganic salt early strength agents such as chlorides, silicates, lithium salts, sulfates and the like or organic early strength agents such as triethanolamine, urea, calcium formate and the like can improve the early strength of the concrete but have limited effect under the condition of single doping, and poor control of the doping amount can increase the internal pores of the concrete, thereby causing negative effects such as reduction of the impermeability and the corrosion resistance of the concrete.
The development of the steam-curing-free precast concrete preparation technology has two important meanings, on one hand, the production energy consumption can be reduced, and the environment is protected; on the other hand, the production efficiency of the concrete prefabricated part can be improved, and the turnover rate of the steel template is improved. The research on the early-strength non-autoclaved concrete technology has great significance to enterprises and society, not only helps the enterprises to save cost, but also can greatly promote the construction of environment-friendly and resource-saving society in China and the industrial development of buildings.
The related patent documents: CN110963735A discloses a nanocrystal core early strength agent for steam-curing-free precast concrete members, which is prepared by the following method: firstly, carrying out sand-stone separation on waste plastic concrete generated in the production process of a commercial mixing and stirring station to obtain waste slurry A; secondly, standing the waste slurry A in a waste water settling tank, and taking the lower layer of thick slurry B; thirdly, placing the thick slurry B into a homogenizing tank, adding a homogenizing agent, stirring, and adding water to dilute the thick slurry B until the solid content is 20% to obtain waste slurry C; the addition amount of the homogenizing agent is 0.5-1% of the mass of the solid in the thick slurry B; and fourthly, grinding the waste slurry C by using a vertical sand mill to obtain the nanocrystal core early strength agent.
According to the technologies, no specific guidance scheme is provided for how to enable the steam-curing-free precast concrete to be subjected to natural curing for 8 hours after the precast concrete is put into a mold without adopting high-temperature steam curing, the mold removal strength is high, and the impermeability and the durability of the precast concrete are improved.
Disclosure of Invention
The invention aims to solve the technical problem of providing the steam curing-free precast concrete, which can be naturally cured for 8 hours and has the form removal strength exceeding 22MPa after the precast concrete is put into a form without adopting high-temperature steam curing, reduce the cracking risk of the concrete and simultaneously improve the impermeability and the durability of the precast concrete.
Therefore, another technical problem to be solved by the present invention is to provide a method for preparing the steam curing-free precast concrete.
In order to solve the technical problems, the technical scheme adopted by the invention is as follows:
the steam-curing-free precast concrete has the technical scheme that the precast concrete is prepared from the following raw materials in parts by weight: 360-380 kg of ordinary portland cement, 10-20 kg of sulphoaluminate cement, 30-50 kg of composite admixture, 600-650 kg of sand, 1150-1200 kg of stones, 130-140 kg of water, 3-5 kg of high-performance water reducing agent, 10-20 kg of nano C-A-S-H namely aluminum-doped hydrated calcium silicate suspension, 5-8 kg of nano silica sol, 2-5 kg of composite early strength agent and 0.5-1 kg of exciting agent.
The composite admixture is prepared from the following raw materials in percentage by mass: 40-50% of metakaolin, 20-30% of zeolite powder, 10-15% of ground rice hull ash, 5-10% of phosphorous slag powder and 5-10% of limestone powder, wherein the sum of the mass percentages of the components in the composite admixture is 100%; the metakaolin is prepared by grinding kaolin after high-temperature calcination at 700-900 ℃ for 2-4 h, and the particle size D50 (median diameter) is less than or equal to 5 um; the zeolite powder is SiO as an active ingredient2+Al2O3White powder with the content of more than or equal to 80% and the particle size of 100-200 nm; the ground rice hull ash is powder with 28d activity index more than or equal to 85 percent, which is prepared by calcining rice hulls at the high temperature of 600-700 ℃ for 2-3 h, naturally cooling and grinding; the specific surface area of the phosphorus slag powder is more than or equal to 500m2The activity index of the industrial waste residue powder is more than or equal to 85 percent in kg and 28 d; the limestone powder has a specific surface area of 550m or more2A white powder with an activity index of more than or equal to 70 percent in terms of/kg and 28 days.
The nano C-A-S-H is an artificially synthesized aluminum-doped calcium silicate hydrate suspension with the average particle size of 50-100 nm, and the preparation method comprises the following steps: adding an aluminum source aqueous solution with the mass percentage concentration of 1-2% into a high polymer dispersion liquid with the solid content of 10-15%, uniformly mixing to prepare a dispersant solution, dropwise adding a calcium source aqueous solution with the mass percentage concentration of 10-15% and a silicon source aqueous solution with the mass percentage concentration of 5-10% into the dispersant solution at the same time, wherein the molar ratio of calcium to silicon (Ca/Si molar ratio) is 1.0-1.7, the molar ratio of aluminum to silicon (Al/Si molar ratio) is 0.2-0.5, the mass ratio of the calcium source aqueous solution to the dispersant solution is 0.7-1: 1, a high-speed shearing dispersion machine is adopted in the dropwise adding process, the high-speed shearing stirring speed is 3000-5000 rpm, the reaction temperature is 10-30 ℃, the calcium source aqueous solution dropwise adding time is 3-4 h, the silicon source aqueous solution dropwise adding time is 1-2 h, and after the two are dropwise added, the stirring is continued for 10-20 min, the obtained milky white suspension with high stability (the stable period is more than or equal to 1 year) and the solid content of 25-30 percent is the nano C-A-S-H with the average grain diameter of 50-100 nm.
The preparation method of the steam curing-free precast concrete comprises the steps of pouring weighed ordinary portland cement, sulphoaluminate cement, composite admixture, sand and stones into a stirrer, dry-stirring for 10-20S, then sequentially adding half of water, a high-performance water reducing agent, nano C-A-S-H, the other half of water, nano silica sol, a composite early strength agent and an exciting agent into the stirrer within 20-30S, stirring for 120-180S, (namely) filling the mixture into a precast concrete mould for natural curing.
In the above technical solution, a preferable technical solution may be: in the steam-curing-free precast concrete, the Portland cement is preferably P.O 42.5.5R Portland cement; the sand is natural sand or machine-made sand, and the fineness modulus ranges from 2.6 to 3.0; the stone is crushed stone or pebble, and is prepared by mixing stone with particle diameter of 5-16mm and stone with particle diameter of 16-31.5mm (16 mm in stone with particle diameter of 16-31.5 mm)<The particle size of the stones is less than or equal to 31.5mm), and the weight ratio of the stones with the particle size of 5-16mm to the stones with the particle size of 16-31.5mm is 2-3: 1. The high-performance water reducing agent is preferably an early-strength polycarboxylate water reducing agent, the water reducing rate is more than or equal to 27%, and the high-performance water reducing agent is preferably a copolymer with an ultralong polyoxyethylene side chain, which is synthesized by polyether macromonomer and other raw materials with the molecular weight of 4000-5000. For example, the early strength type polycarboxylate water reducer ZM or GK-3000 early strength type polycarboxylate water reducer can be sold in the market. The high molecular polymer dispersion liquid is an early strength polycarboxylate superplasticizer, such as a commercially available ViscoCrete 20HE early strength polycarboxylate superplasticizer (brand: Cika). The calcium source water solution is prepared by dissolving calcium chloride or calcium nitrate in water; the silicon source water solution is prepared by dissolving potassium metasilicate or sodium silicate nonahydrate in water; the aluminum source aqueous solution is prepared by dissolving aluminum nitrate or sodium metaaluminate in water. The nano silica sol is aluminum modified nano silicon dioxide dispersion liquid, SiO2The content is more than or equal to 15 percent, and the particle size of the nano particles is 5-20 nm. This technique is per se prior art. The composite early strength agent is organicThe organic matter is one or a combination of a plurality of raw materials of triethanolamine, diethanolamine, diethanol monoisopropanolamine and tetrahydroxypropyl ethylenediamine, and the mixture ratio is arbitrary when the organic matter and the inorganic matter are mixed according to the weight ratio of 3: 7; the inorganic matter is one or the combination of several raw materials of lithium sulfate, lithium nitrate and calcium nitrate, and the mixture ratio is arbitrary when the inorganic matter is combined. The exciting agent is one or more of sodium sulfate, sodium carbonate and sodium metasilicate (pentahydrate).
Among the above-described technical solutions, preferred technical solutions may be the following embodiments 1 to 3.
The steam-curing-free precast concrete has good performance, adopts the composite admixture particularly suitable for the steam-curing-free precast concrete, preferably selects various industrial waste residues, contains the excitant component, can promote the composite admixture to generate a composite gelling effect, a closest particle accumulation system and a super superposition effect, and further improves the strength and the durability of the concrete. The early-strength type polycarboxylic acid high-performance water reducing agent component has a unique molecular structure, improves the construction performance of precast concrete, reduces the viscosity of the concrete, is beneficial to discharging air bubbles during construction vibration, improves the appearance of the precast concrete, and can also greatly improve the form removal strength of the steam-curing-free precast concrete. The nano calcium aluminosilicate component (nano C-A-S-H, namely the hydrated calcium silicate suspension doped with aluminum) has good compatibility with cement, can generate a nano crystal nucleus effect, reduces a cement hydration nucleation barrier, promotes the hydration of cement minerals, shortens the setting time of the steam-curing-free precast concrete, and improves the ultra-early strength within 12H. The nanometer silica sol component can react with Ca (OH) generated in the hydration reaction of cement2Form amorphous gel C-S-H, and further improve the early strength of the concrete. Compared with the commonly used silica fume (silicon micropowder), the surface of the nano silica sol is fully distributed with hydroxyl groups, has higher specific surface area, has higher reaction activity than the silicon micropowder, and has better dispersion effect, lower mixing amount and better early strength effect.
Compared with the prior art, the steam-curing-free precast concrete has the following beneficial effects:
(1) the special early strength type high-performance water reducing agent, the nano calcium aluminosilicate, the nano silica sol and the composite early strength agent for the steam curing-free precast concrete are adopted, so that the early strength of the precast concrete under the natural curing condition is greatly improved, the 8-hour formwork removal strength can reach over 22MPa, the production energy consumption is reduced, the environment is protected, the turnover rate of a steel formwork is improved, the production efficiency of a concrete precast component is improved, and the method has good economic benefits and social benefits. (2) The steam-curing-free precast concrete disclosed by the invention is smaller in cracking risk, greatly improved in impermeability, better in durability and better in appearance quality of concrete.
In conclusion, the steam curing-free precast concrete provided by the invention is simple in preparation method, and can be naturally cured for 8 hours to ensure that the form removal strength exceeds 22MPa after the precast concrete is put into a form without adopting high-temperature steam curing, so that the risk of cracking of the concrete is reduced, the impermeability and the durability of the precast concrete are improved, the energy consumption is greatly saved, and the turnover efficiency of the form is improved. Compared with the prior art, the invention saves the energy consumption by more than 12 percent and improves the turnover efficiency of the die by more than 15 percent.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below with reference to the embodiments. It is to be understood that the embodiments described are only a few embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example 1: the steam-curing-free precast concrete is prepared from the following raw materials in parts by weight: 360kg of ordinary portland cement P.O42.5R ordinary portland cement, 20kg of sulphoaluminate cement, 50kg of composite admixture, 630kg of sand, 1150kg of stones, 135kg of water, 3kg of high-performance water reducing agent, 15kg of nano C-A-S-H (hydrated calcium aluminosilicate) namely aluminum-doped hydrated calcium silicate suspension, 5kg of nano silica sol, 3kg of composite early strength agent and 0.5kg of exciting agent.
The composite admixture is prepared from the following raw materials in percentage by mass: metakaolin 40 percent of zeolite powder, 25 percent of ground rice hull ash, 10 percent of phosphorous slag powder and 10 percent of limestone powder. The metakaolin is prepared by calcining kaolin at the high temperature of 800 ℃ for 3h and then grinding, and the particle size D50 (median diameter) of the metakaolin is less than or equal to 5 um; the zeolite powder is SiO as an active ingredient2+Al2O3White powder with the content of more than or equal to 80% and the particle size of 120-140 nm; the ground rice hull ash is powder with 28d activity index more than or equal to 85 percent, which is prepared by calcining rice hulls at the high temperature of 650 ℃ for 3 hours, naturally cooling and grinding; the specific surface area of the phosphorus slag powder is more than or equal to 500m2The activity index of the industrial waste residue powder is more than or equal to 85 percent in kg and 28 d; the limestone powder has a specific surface area of 550m or more2A white powder with an activity index of more than or equal to 70 percent in terms of/kg and 28 days.
The nanometer C-A-S-H (hydrated calcium aluminosilicate) is artificially synthesized aluminum-doped hydrated calcium silicate suspension with the average grain diameter of 80nm, and the preparation method comprises the following steps: adding an aluminum source aqueous solution with the mass percentage concentration of 1% into a high molecular polymer dispersion liquid with the solid content of 10%, uniformly mixing to prepare a dispersant solution, simultaneously dropwise adding a calcium source aqueous solution with the mass percentage concentration of 10% and a silicon source aqueous solution with the mass percentage concentration of 5% into the dispersant solution, wherein the calcium-silicon molar ratio (Ca/Si molar ratio) is 1.0, the aluminum-silicon molar ratio (Al/Si molar ratio) is 0.3, the mass ratio of the calcium source aqueous solution to the dispersant solution is 0.8:1, a high-speed shearing dispersion machine is adopted in the dropwise adding process, the high-speed shearing stirring speed is 3000rpm, the reaction temperature is 30 ℃, the calcium source aqueous solution is dropwise added for 3 hours, the silicon source aqueous solution is dropwise added for 1 hour, and after the two are dropwise added, the stirring is continued for 10 minutes, so that the obtained milky white suspension with the high stability (the stable period is more than or equal to 1 year), the solid content of which is 25%, is the nano C-A-S-H (hydrated aluminosilicate) with Calcium).
The sand is machine-made sand (or natural sand), and the fineness modulus ranges from 2.6 to 3.0; the stones are crushed stones or pebbles, the stones are formed by mixing stones with the particle size of 5-16mm and stones with the particle size of 16-31.5mm, and the weight ratio of the stones with the particle size of 5-16mm to the stones with the particle size of 16-31.5mm is 2: 1. The high-performance water reducing agent is an early-strength polycarboxylate water reducing agent, has the water reducing rate of 30 percent, and is prepared from polyether macromonomer with the molecular weight of 5000 and other raw materialsSynthesized copolymer with super-long polyoxyethylene side chain. For example, the water reducing agent may be a commercially available early strength polycarboxylate water reducing agent ZM (or a GK-3000 early strength polycarboxylate water reducing agent). The high molecular polymer dispersion liquid is an early strength polycarboxylate superplasticizer, such as a commercially available ViscoCrete 20HE early strength polycarboxylate superplasticizer (brand: Cika). The calcium source water solution is prepared by dissolving calcium chloride in water; the silicon source water solution is prepared by dissolving potassium metasilicate in water; the aluminum source aqueous solution is prepared by dissolving aluminum nitrate in water. The nano silica sol is aluminum modified nano silicon dioxide dispersion liquid, SiO2The content is 20%, and the particle size of the nano particles is 10 nm. The composite early strength agent is formed by mixing organic matters and inorganic matters according to the ratio of 3:7, wherein the organic matters are diethanol monoisopropanolamine; the inorganic substance is calcium nitrate. The excitant is sodium metasilicate.
The preparation method of the steam curing-free precast concrete comprises the steps of pouring weighed ordinary portland cement, sulphoaluminate cement, composite admixture, sand and stones into a stirrer, dry-stirring for 15S, then sequentially adding half of water, a high-performance water reducing agent, nano C-A-S-H, the other half of water, nano silica sol, a composite early strength agent and an exciting agent into the stirrer within 20S, stirring for 150S, and filling the mixture into a precast concrete mould for natural curing.
Example 2: the steam-curing-free precast concrete is prepared from the following raw materials in parts by weight: 370kg of ordinary portland cement (P.O42.5R ordinary portland cement), 10kg of sulphoaluminate cement, 40kg of composite admixture, 650kg of sand, 1180kg of stones, 140kg of water, 4kg of high-performance water reducing agent, 10kg of nano C-A-S-H (hydrated calcium aluminosilicate) namely aluminum-doped hydrated calcium silicate suspension, 8kg of nano silica sol, 2kg of composite early strength agent and 0.8kg of exciting agent.
The composite admixture is prepared from the following raw materials in percentage by mass: 50% of metakaolin, 20% of zeolite powder, 15% of ground rice hull ash, 5% of phosphorous slag powder and 10% of limestone powder. The metakaolin is prepared by grinding kaolin after high-temperature calcination at 880 ℃ for 4h, and the particle size D50 (median diameter) of the metakaolin is less than or equal to 5 um; the zeolite powder isActive ingredient SiO2+Al2O3White powder with the content of more than or equal to 80% and the particle size of 100-120 nm; the ground rice hull ash is powder with 28d activity index more than or equal to 85 percent, which is prepared by natural cooling and grinding after the rice hulls are calcined at the high temperature of 680 ℃ for 3 hours; the specific surface area of the phosphorus slag powder is more than or equal to 500m2The activity index of the industrial waste residue powder is more than or equal to 85 percent in kg and 28 d; the limestone powder has a specific surface area of 550m or more2A white powder with an activity index of more than or equal to 70 percent in terms of/kg and 28 days.
The nanometer C-A-S-H (hydrated calcium aluminosilicate) is artificially synthesized aluminum-doped hydrated calcium silicate suspension with the average grain diameter of 50nm, and the preparation method comprises the following steps: adding an aluminum source aqueous solution with the mass percentage concentration of 1.5% into a high molecular polymer dispersion liquid with the solid content of 13%, uniformly mixing to prepare a dispersant solution, simultaneously dropwise adding a calcium source aqueous solution with the mass percentage concentration of 12% and a silicon source aqueous solution with the mass percentage concentration of 8% into the dispersant solution, wherein the calcium-silicon molar ratio (Ca/Si molar ratio) is 1.5, the aluminum-silicon molar ratio (Al/Si molar ratio) is 0.5, the mass ratio of the calcium source aqueous solution to the dispersant solution is 1:1, a high-speed shearing dispersion machine is adopted in the dropwise adding process, the high-speed shearing stirring speed is 5000rpm, the reaction temperature is 20 ℃, the calcium source aqueous solution is dropwise added for 4H, the silicon source aqueous solution is dropwise added for 2H, and after the dropwise adding of the two, the stirring is continued for 20min, so that the obtained milky white suspension liquid with the high stability (the stable period is more than or equal to 1 year) and the solid content of 26%, namely the nano C-A-S-H (hydrated aluminosilicate Calcium).
The sand is natural sand (or machine-made sand), and the fineness modulus ranges from 2.6 to 3.0; the stones are crushed stones or pebbles, the stones are formed by mixing stones with the particle size of 5-16mm and stones with the particle size of 16-31.5mm, and the weight ratio of the stones with the particle size of 5-16mm to the stones with the particle size of 16-31.5mm is 3: 1. The high-performance water reducing agent is an early-strength polycarboxylate water reducing agent, has a water reducing rate of 28 percent, and is a copolymer with an ultralong polyoxyethylene side chain, which is synthesized by polyether macromonomer and other raw materials with the molecular weight of 4500. For example, the water reducing agent may be a commercially available GK-3000 early strength type polycarboxylic acid water reducing agent (or early strength type polycarboxylic acid water reducing agent ZM). The high molecular polymer dispersion liquid is an early-strength polycarboxylate superplasticizerFor example, the water reducer may be a commercially available ViscoCrete 20HE type early strength polycarboxylic acid water reducer (brand: Cika). The calcium source water solution is prepared by dissolving calcium nitrate in water; the silicon source water solution is prepared by dissolving sodium silicate nonahydrate in water; the aluminum source aqueous solution is prepared by dissolving sodium metaaluminate in water. The nano silica sol is aluminum modified nano silicon dioxide dispersion liquid, SiO2The content is 15%, and the particle size of the nano particles is 5 nm. The composite early strength agent is formed by mixing an organic matter and an inorganic matter according to the weight ratio of 3:7, wherein the organic matter is the combination of two raw materials of diethanolamine and tetrahydroxypropyl ethylenediamine, and the weight ratio of the diethanolamine to the tetrahydroxypropyl ethylenediamine is 1: 3; the inorganic substance is lithium sulfate. The activator is sodium carbonate.
The preparation method of the steam curing-free precast concrete comprises the steps of pouring weighed ordinary portland cement, sulphoaluminate cement, composite admixture, sand and stones into a stirrer, dry-stirring for 15S, then sequentially adding half of water, a high-performance water reducing agent, nano C-A-S-H, the other half of water, nano silica sol, a composite early strength agent and an exciting agent into the stirrer within 30S, stirring for 180S, and filling the mixture into a precast concrete mould for natural curing.
Example 3: the steam-curing-free precast concrete is prepared from the following raw materials in parts by weight: 380kg of ordinary portland cement, namely P.O42.5R ordinary portland cement, 15kg of sulphoaluminate cement, 30kg of composite admixture, 650kg of sand, 1200kg of stones, 140kg of water, 5kg of high-performance water reducing agent, 20kg of nano C-A-S-H (hydrated calcium aluminosilicate) namely aluminum-doped hydrated calcium silicate suspension, 6kg of nano silica sol, 5kg of composite early strength agent and 1kg of exciting agent.
The composite admixture is prepared from the following raw materials in percentage by mass: 45% of metakaolin, 30% of zeolite powder, 15% of ground rice hull ash, 5% of phosphorous slag powder and 5% of limestone powder. The metakaolin is prepared by grinding kaolin after high-temperature calcination at 720 ℃ for 3.5h, and the particle size D50 (median diameter) of the metakaolin is less than or equal to 5 um; the zeolite powder is SiO as an active ingredient2+Al2O3White powder with the content of more than or equal to 80% and the particle size of 180-200 nm; the above fine grindingThe rice hull ash is powder with 28d activity index more than or equal to 85 percent, which is prepared by calcining rice hulls at the high temperature of 650 ℃ for 3 hours, naturally cooling and grinding; the specific surface area of the phosphorus slag powder is more than or equal to 500m2The activity index of the industrial waste residue powder is more than or equal to 85 percent in kg and 28 d; the limestone powder has a specific surface area of 550m or more2A white powder with an activity index of more than or equal to 70 percent in terms of/kg and 28 days.
The nanometer C-A-S-H (hydrated calcium aluminosilicate) is artificially synthesized aluminum-doped hydrated calcium silicate suspension with the average grain diameter of 100nm, and the preparation method comprises the following steps: adding an aluminum source aqueous solution with the mass percentage concentration of 2% into a high-molecular polymer dispersion liquid with the solid content of 10%, uniformly mixing to prepare a dispersant solution, simultaneously dropwise adding a calcium source aqueous solution with the mass percentage concentration of 15% and a silicon source aqueous solution with the mass percentage concentration of 10% into the dispersant solution, wherein the calcium-silicon molar ratio (Ca/Si molar ratio) is 1.2, the aluminum-silicon molar ratio (Al/Si molar ratio) is 0.4, the mass ratio of the calcium source aqueous solution to the dispersant solution is 0.8:1, a high-speed shearing dispersion machine is adopted in the dropwise adding process, the high-speed shearing stirring speed is 4000rpm, the reaction temperature is 12 ℃, the calcium source aqueous solution is dropwise added for 4H, the silicon source aqueous solution is dropwise added for 1H, and after the dropwise adding of the two, the stirring is continued for 15min, so that a milky white suspension liquid with the high stability (the stable period is more than or equal to 1 year) and the solid content of 25%, namely the nano C-A-S-H (hydrated aluminosilicate) Calcium); the sand is machine-made sand, and the fineness modulus ranges from 2.6 to 3.0; the stones are crushed stones or pebbles, the stones are formed by mixing stones with the particle size of 5-16mm and stones with the particle size of 16-31.5mm, and the weight ratio of the stones with the particle size of 5-16mm to the stones with the particle size of 16-31.5mm is 2.5: 1. The high-performance water reducing agent is an early-strength polycarboxylate water reducing agent, has the water reducing rate of 30 percent, and is a copolymer with an ultralong polyoxyethylene side chain, which is synthesized by polyether macromonomer and other raw materials with the molecular weight of 5000. For example, the water reducing agent may be a commercially available early strength polycarboxylate water reducing agent ZM (or a GK-3000 early strength polycarboxylate water reducing agent). The high molecular polymer dispersion liquid is an early strength polycarboxylate superplasticizer, such as a commercially available ViscoCrete 20HE early strength polycarboxylate superplasticizer (brand: Cika). The calcium source water solution is prepared by dissolving calcium chloride in water; silicon source waterThe solution is prepared by dissolving sodium silicate nonahydrate in water to prepare silicon source water solution; the aluminum source aqueous solution is prepared by dissolving aluminum nitrate in water. The nano silica sol is aluminum modified nano silicon dioxide dispersion liquid, SiO2The content is 25 percent, and the particle size of the nano particles is 15 nm. The composite early strength agent is formed by mixing an organic matter and an inorganic matter according to the weight ratio of 3:7, wherein the organic matter is the combination of two raw materials, namely triethanolamine and tetrahydroxypropylethylenediamine, and the weight ratio of the triethanolamine to the tetrahydroxypropylethylenediamine is 1: 2.5; the inorganic matter is the combination of two raw materials of lithium sulfate and calcium nitrate, and the weight ratio of the lithium sulfate to the calcium nitrate is 1: 1.5; the activator is sodium sulfate.
The preparation method of the steam curing-free precast concrete comprises the steps of pouring weighed ordinary portland cement, sulphoaluminate cement, composite admixture, sand and stones into a stirrer, dry-stirring for 20S, then sequentially adding half of water, a high-performance water reducing agent, nano C-A-S-H, the other half of water, nano silica sol, a composite early strength agent and an exciting agent into the stirrer within 30S, stirring for 170S, and filling the mixture into a precast concrete mould for natural curing.
The following are the experimental part of the invention:
comparative example 1: the raw materials and the quality thereof are different from those in the example 3 only in that nano C-A-S-H (hydrated calcium aluminosilicate) is not added, the preparation method is the same, and the curing modes are all natural curing.
Comparative example 2: the raw materials and the quality thereof are different from those in the embodiment 3 in that nano C-A-S-H (hydrated calcium aluminosilicate) and nano silica sol are not added, the preparation method is the same, but the curing mode is steam curing at 60 ℃.
Performance tests are carried out on the precast concrete of the examples and the comparative examples according to GB/T50080-2016 Standard test method for Performance of common concrete mixture, GB/T50081-2019 Standard test method for physical and mechanical Properties of concrete and GB/T50082-2009 Standard test method for Long-term Performance and durability of common concrete. The curing conditions were 15 ℃ natural curing, and the test results are shown in table 1.
TABLE 1 precast concrete Properties
As can be seen from Table 1, the concrete-filled steel plate has good performance in each embodiment, the slump of the concrete after the concrete is taken out of the machine meets the requirement of 60-80 mm, the compressive strength of the concrete after 8 hours exceeds 22MPa and far exceeds the requirement that the demolding and lifting strength of GB/T51231-2016 (technical Standard for fabricated concrete buildings) is more than or equal to 15MPa under the condition of natural curing at 15 ℃, and meanwhile, the mechanical property of the concrete after the later period is good, the compressive strength of the concrete after 28 days is more than 60MPa, and the design requirement is met. The non-autoclaved concrete has the advantages of lower chloride ion permeability coefficient, good impermeability and obviously improved durability compared with autoclaved concrete.
In conclusion, the steam curing-free precast concrete has good performance, the preparation method of the steam curing-free precast concrete is simple, green and environment-friendly, the precast concrete can be naturally cured for 8 hours after being molded without adopting high-temperature steam curing, the demolding strength is high (the demolding strength exceeds 22MPa), the risk of cracking of the concrete is reduced, the durability of the precast concrete is improved, the anti-permeability performance is good, the energy consumption is greatly saved, the turnover efficiency of the mold is improved, and good economic benefit and social benefit are achieved. Compared with the prior art, the invention saves the energy consumption by more than 12 percent and improves the turnover efficiency of the die by more than 15 percent.
Claims (10)
1. The steam-curing-free precast concrete is characterized by being prepared from the following raw materials in parts by weight: 360-380 kg of ordinary portland cement, 10-20 kg of sulphoaluminate cement, 30-50 kg of composite admixture, 600-650 kg of sand, 1150-1200 kg of stones, 130-140 kg of water, 3-5 kg of high-performance water reducing agent, 10-20 kg of nano C-A-S-H namely aluminum-doped hydrated calcium silicate suspension, 5-8 kg of nano silica sol, 2-5 kg of composite early strength agent and 0.5-1 kg of exciting agent;
the composite admixture is prepared from the following raw materials in percentage by mass: metakaolin 40-50 wt%, zeolite powder 20-30 wt%, ground rice hull ash 10-15 wt%, phosphorous slag powder 5-10 wt%, limestone powder 5-10 wt%, and composite admixtureThe sum of the quantity percentages is 100 percent; the metakaolin is prepared by grinding kaolin after high-temperature calcination at 700-900 ℃ for 2-4 h, and the particle size D50 is less than or equal to 5 um; the zeolite powder is SiO as an active ingredient2+Al2O3White powder with the content of more than or equal to 80% and the particle size of 100-200 nm; the ground rice hull ash is powder with 28d activity index more than or equal to 85 percent, which is prepared by calcining rice hulls at the high temperature of 600-700 ℃ for 2-3 h, naturally cooling and grinding; the specific surface area of the phosphorus slag powder is more than or equal to 500m2The activity index of the industrial waste residue powder is more than or equal to 85 percent in kg and 28 d; the limestone powder has a specific surface area of 550m or more2A white powder with an activity index of more than or equal to 70 percent in kg and 28 d;
the nano C-A-S-H is an artificially synthesized aluminum-doped calcium silicate hydrate suspension with the average particle size of 50-100 nm, and the preparation method comprises the following steps: adding an aluminum source aqueous solution with the mass percentage concentration of 1-2% into a high polymer dispersion liquid with the solid content of 10-15%, uniformly mixing to prepare a dispersant solution, dripping a calcium source aqueous solution with the mass percentage concentration of 10-15% and a silicon source aqueous solution with the mass percentage concentration of 5-10% into the dispersant solution at the same time, wherein the molar ratio of calcium to silicon is 1.0-1.7, the molar ratio of aluminum to silicon is 0.2-0.5, the mass ratio of the calcium source aqueous solution to the dispersant solution is 0.7-1: 1, a high-speed shearing dispersion machine is adopted in the dripping process, the high-speed shearing stirring speed is 3000-5000 rpm, the reaction temperature is 10-30 ℃, the dripping time of the calcium source aqueous solution is 3-4 h, the dripping time of the silicon source aqueous solution is 1-2 h, and after the dripping of the calcium source aqueous solution and the dispersant solution is finished, the stirring is continued for 10-20 min, so that the obtained milky white suspension with the high-stability and the solid content of 25-30%, namely the nano C -H;
the preparation method of the steam curing-free precast concrete comprises the steps of pouring weighed ordinary portland cement, sulphoaluminate cement, composite admixture, sand and stones into a stirrer, dry-stirring for 10-20S, then sequentially adding half of water, a high-performance water reducing agent, nano C-A-S-H, the other half of water, nano silica sol, a composite early strength agent and an exciting agent into the stirrer within 20-30S, stirring for 120-180S, and filling the mixture into a precast concrete mould for natural curing.
2. The steam-curing free precast concrete of claim 1, wherein the portland cement is P.O 42.5.5R portland cement; the sand is natural sand or machine-made sand, and the fineness modulus ranges from 2.6 to 3.0; the stones are broken stones or pebbles, the stones are formed by mixing stones with the particle size of 5-16mm and stones with the particle size of 16-31.5mm, and the weight ratio of the stones with the particle size of 5-16mm to the stones with the particle size of 16-31.5mm is 2-3: 1.
3. The steam-curing-free precast concrete of claim 1, characterized in that the high-performance water reducing agent is an early-strength polycarboxylate water reducing agent, the water reducing rate is not less than 27%, and the high-performance water reducing agent is a copolymer with an ultralong polyoxyethylene side chain, which is synthesized by polyether macromonomer with the molecular weight of 4000-5000 and other raw materials; the high molecular polymer dispersion liquid is an early-strength polycarboxylate superplasticizer.
4. The steam-curing-free precast concrete of claim 1, wherein the calcium source aqueous solution is prepared by dissolving calcium chloride or calcium nitrate in water; the silicon source water solution is prepared by dissolving potassium metasilicate or sodium silicate nonahydrate in water; the aluminum source aqueous solution is prepared by dissolving aluminum nitrate or sodium metaaluminate in water.
5. The steam-curing-free precast concrete of claim 1, wherein the nano silica sol is an aluminum-modified nano silica dispersion, SiO2The content is more than or equal to 15 percent, and the particle size of the nano particles is 5-20 nm.
6. The steam-curing-free precast concrete of claim 1, wherein the composite early strength agent is formed by mixing an organic substance and an inorganic substance according to a weight ratio of 3:7, the organic substance is one or a combination of several raw materials of triethanolamine, diethanolamine, diethanol monoisopropanolamine and tetrahydroxypropyl ethylenediamine, and the mixture ratio is arbitrary when the organic substance and the inorganic substance are combined; the inorganic matter is one or the combination of several raw materials of lithium sulfate, lithium nitrate and calcium nitrate, and the mixture ratio is arbitrary when the inorganic matter is combined.
7. The steam-curing-free precast concrete of claim 1, wherein the activator is one or more selected from the group consisting of sodium sulfate, sodium carbonate, and sodium metasilicate.
8. The steam-curing-free precast concrete according to claim 1, which is characterized by being prepared from the following raw materials in parts by weight: 370kg of ordinary portland cement (P.O42.5R ordinary portland cement), 10kg of sulphoaluminate cement, 40kg of composite admixture, 650kg of sand, 1180kg of stones, 140kg of water, 4kg of high-performance water reducing agent, 10kg of nano C-A-S-H (aluminum-doped hydrated calcium silicate suspension, 8kg of nano silica sol, 2kg of composite early strength agent and 0.8kg of exciting agent;
the composite admixture is prepared from the following raw materials in percentage by mass: 50% of metakaolin, 20% of zeolite powder, 15% of ground rice hull ash, 5% of phosphorous slag powder and 10% of limestone powder. The metakaolin is prepared by grinding kaolin after high-temperature calcination at 880 ℃ for 4h, and the particle size D50 of the metakaolin is less than or equal to 5 um; the zeolite powder is SiO as an active ingredient2+Al2O3White powder with the content of more than or equal to 80% and the particle size of 100-120 nm; the ground rice hull ash is powder with 28d activity index more than or equal to 85 percent, which is prepared by natural cooling and grinding after the rice hulls are calcined at the high temperature of 680 ℃ for 3 hours; the specific surface area of the phosphorus slag powder is more than or equal to 500m2The activity index of the industrial waste residue powder is more than or equal to 85 percent in kg and 28 d; the limestone powder has a specific surface area of 550m or more2A white powder with an activity index of more than or equal to 70 percent in kg and 28 d;
the nano C-A-S-H is artificially synthesized aluminum-doped calcium silicate hydrate suspension with the average particle size of 50nm, and the preparation method comprises the following steps: adding an aluminum source aqueous solution with the mass percentage concentration of 1.5% into a high molecular polymer dispersion liquid with the solid content of 13%, uniformly mixing to prepare a dispersant solution, mixing a calcium source water solution with the mass percentage concentration of 12 percent and a silicon source water solution with the mass percentage concentration of 8 percent, simultaneously dropwise adding the calcium source aqueous solution and the dispersing agent solution into the dispersing agent solution, wherein the molar ratio of calcium to silicon is 1.5, the molar ratio of aluminum to silicon is 0.5, the mass ratio of the calcium source aqueous solution to the dispersing agent solution is 1:1, a high-speed shearing dispersion machine is adopted in the dropwise adding process, the high-speed shearing stirring speed is 5000rpm, the reaction temperature is 20 ℃, the dropwise adding time of the calcium source aqueous solution is 4 hours, the dropwise adding time of the silicon source aqueous solution is 2 hours, after the dropwise adding of the calcium source aqueous solution and the dispersing, continuously stirring for 20min to obtain milky white suspension with high stability and solid content of 26%, namely nano C-A-S-H with average particle size of 50 nm;
the sand is natural sand, and the fineness modulus ranges from 2.6 to 3.0; the stones are crushed stones or pebbles, the stones are formed by mixing stones with the particle size of 5-16mm and stones with the particle size of 16-31.5mm, and the weight ratio of the stones with the particle size of 5-16mm to the stones with the particle size of 16-31.5mm is 3: 1. The high-performance water reducing agent is an early-strength polycarboxylate water reducing agent, has a water reducing rate of 28 percent, and is a copolymer with an ultra-long polyoxyethylene side chain, which is synthesized by polyether macromonomer and other raw materials with the molecular weight of 4500; the high molecular polymer dispersion liquid is an early-strength polycarboxylate superplasticizer; the calcium source water solution is prepared by dissolving calcium nitrate in water; the silicon source water solution is prepared by dissolving sodium silicate nonahydrate in water; the aluminum source aqueous solution is prepared by dissolving sodium metaaluminate in water; the nano silica sol is aluminum modified nano silicon dioxide dispersion liquid, SiO2The content is 15 percent, and the particle size of the nano particles is 5 nm; the composite early strength agent is formed by mixing an organic matter and an inorganic matter according to the weight ratio of 3:7, wherein the organic matter is the combination of two raw materials of diethanolamine and tetrahydroxypropyl ethylenediamine, and the weight ratio of the diethanolamine to the tetrahydroxypropyl ethylenediamine is 1: 3; the inorganic substance is lithium sulfate. The excitant is sodium carbonate;
the preparation method of the steam curing-free precast concrete comprises the steps of pouring weighed ordinary portland cement, sulphoaluminate cement, composite admixture, sand and stones into a stirrer, dry-stirring for 15S, then sequentially adding half of water, a high-performance water reducing agent, nano C-A-S-H, the other half of water, nano silica sol, a composite early strength agent and an exciting agent into the stirrer within 30S, stirring for 180S, and filling the mixture into a precast concrete mould for natural curing.
9. The steam-curing-free precast concrete according to claim 1, which is characterized by being prepared from the following raw materials in parts by weight: 380kg of ordinary portland cement (P.O42.5R ordinary portland cement), 15kg of sulphoaluminate cement, 30kg of composite admixture, 650kg of sand, 1200kg of stones, 140kg of water, 5kg of high-performance water reducing agent, 20kg of nano C-A-S-H (aluminum-doped hydrated calcium silicate suspension), 6kg of nano silica sol, 5kg of composite early strength agent and 1kg of exciting agent;
the composite admixture is prepared from the following raw materials in percentage by mass: 45% of metakaolin, 30% of zeolite powder, 15% of ground rice hull ash, 5% of phosphorous slag powder and 5% of limestone powder. The metakaolin is prepared by grinding kaolin after high-temperature calcination at 720 ℃ for 3.5h, and the particle size D50 is less than or equal to 5 um; the zeolite powder is SiO as an active ingredient2+Al2O3White powder with the content of more than or equal to 80% and the particle size of 180-200 nm; the ground rice hull ash is powder with 28d activity index more than or equal to 85 percent, which is prepared by calcining rice hulls at the high temperature of 650 ℃ for 3 hours, naturally cooling and grinding; the specific surface area of the phosphorus slag powder is more than or equal to 500m2The activity index of the industrial waste residue powder is more than or equal to 85 percent in kg and 28 d; the limestone powder has a specific surface area of 550m or more2A white powder with an activity index of more than or equal to 70 percent in kg and 28 d;
the nano C-A-S-H is artificially synthesized aluminum-doped calcium silicate hydrate suspension with the average particle size of 100nm, and the preparation method comprises the following steps: adding an aluminum source aqueous solution with the mass percentage concentration of 2% into a high-molecular polymer dispersion liquid with the solid content of 10%, uniformly mixing to prepare a dispersant solution, simultaneously dropwise adding a calcium source aqueous solution with the mass percentage concentration of 15% and a silicon source aqueous solution with the mass percentage concentration of 10% into the dispersant solution, wherein the molar ratio of calcium to silicon is 1.2, the molar ratio of aluminum to silicon is 0.4, the mass ratio of the calcium source aqueous solution to the dispersant solution is 0.8:1, a high-speed shearing dispersion machine is adopted in the dropwise adding process, the high-speed shearing stirring speed is 4000rpm, the reaction temperature is 12 ℃, the dropwise adding time of the calcium source aqueous solution is 4 hours, the dropwise adding time of the silicon source aqueous solution is 1 hour, and after the dropwise adding of the calcium source aqueous solution and the dispersant solution, the stirring is continued for 15 minutes, so that the milkyThe color suspension is the nano C-A-S-H with the average grain diameter of 100 nm; the sand is machine-made sand, and the fineness modulus ranges from 2.6 to 3.0; the stones are broken stones or pebbles, the stones are formed by mixing stones with the particle size of 5-16mm and stones with the particle size of 16-31.5mm, and the weight ratio of the stones with the particle size of 5-16mm to the stones with the particle size of 16-31.5mm is 2.5: 1; the high-performance water reducing agent is an early-strength polycarboxylate water reducing agent, has a water reducing rate of 30 percent, and is a copolymer with an ultra-long polyoxyethylene side chain, which is synthesized by polyether macromonomer and other raw materials with the molecular weight of 5000; the high molecular polymer dispersion liquid is an early-strength polycarboxylate superplasticizer; the calcium source water solution is prepared by dissolving calcium chloride in water; the silicon source water solution is prepared by dissolving sodium silicate nonahydrate in water; the aluminum source aqueous solution is prepared by dissolving aluminum nitrate in water; the nano silica sol is aluminum modified nano silicon dioxide dispersion liquid, SiO2The content is 25 percent, and the particle size of the nano particles is 15 nm; the composite early strength agent is formed by mixing an organic matter and an inorganic matter according to the weight ratio of 3:7, wherein the organic matter is the combination of two raw materials, namely triethanolamine and tetrahydroxypropylethylenediamine, and the weight ratio of the triethanolamine to the tetrahydroxypropylethylenediamine is 1: 2.5; the inorganic matter is the combination of two raw materials of lithium sulfate and calcium nitrate, and the weight ratio of the lithium sulfate to the calcium nitrate is 1: 1.5; the excitant is sodium sulfate;
the preparation method of the steam curing-free precast concrete comprises the steps of pouring weighed ordinary portland cement, sulphoaluminate cement, composite admixture, sand and stones into a stirrer, dry-stirring for 20S, then sequentially adding half of water, a high-performance water reducing agent, nano C-A-S-H, the other half of water, nano silica sol, a composite early strength agent and an exciting agent into the stirrer within 30S, stirring for 170S, and filling the mixture into a precast concrete mould for natural curing.
10. The preparation method of the steam curing-free precast concrete of claim 1 is characterized in that when the concrete is prepared, the weighed ordinary portland cement, sulphoaluminate cement, composite admixture, sand and stones are poured into a stirrer, the mixture is dry-mixed for 10-20S, then half of water, high-performance water reducing agent, nano C-A-S-H, the other half of water, nano silica sol, composite early strength agent and exciting agent are sequentially added into the stirrer within 20-30S, the mixture is stirred for 120-180S, and the mixture is filled into a precast concrete mould for natural curing.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN114292044A (en) * | 2022-01-24 | 2022-04-08 | 河南鑫再生新材料科技有限公司 | Method for recovering aluminum from lithium iron phosphate positive electrode material, obtained material and application |
| CN115259709A (en) * | 2022-09-26 | 2022-11-01 | 石家庄市长安育才建材有限公司 | Modified glass bead and preparation method thereof, coagulation-accelerating early strength agent and preparation method thereof |
| CN115893895A (en) * | 2023-01-09 | 2023-04-04 | 石家庄市长安育才建材有限公司 | Coagulation accelerating early strength agent, preparation method thereof and concrete composition |
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2020
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN114292044A (en) * | 2022-01-24 | 2022-04-08 | 河南鑫再生新材料科技有限公司 | Method for recovering aluminum from lithium iron phosphate positive electrode material, obtained material and application |
| CN115259709A (en) * | 2022-09-26 | 2022-11-01 | 石家庄市长安育才建材有限公司 | Modified glass bead and preparation method thereof, coagulation-accelerating early strength agent and preparation method thereof |
| CN115259709B (en) * | 2022-09-26 | 2023-01-06 | 石家庄市长安育才建材有限公司 | Modified glass bead and preparation method thereof, coagulation-accelerating early strength agent and preparation method thereof |
| CN115893895A (en) * | 2023-01-09 | 2023-04-04 | 石家庄市长安育才建材有限公司 | Coagulation accelerating early strength agent, preparation method thereof and concrete composition |
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