Dormancy-awakening agent for mortar and concrete and use method of dormancy-awakening agent
By using dormant-wake agents such as sucrose and aluminum sulfate in cement concrete, the hydration process of cement is slowed down and quickly awakened when needed, the slump loss and strength reduction of fresh cement concrete during long-term transportation and rapid solidification is solved, and efficient transportation of concrete and excellent construction performance are achieved.
Patent Information
- Application Number
- CN202311584185.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-11-25
- Publication Date
- 2025-03-18
AI Technical Summary
Fresh cement concrete faces problems such as slump loss, stacking of construction waste, reduced concrete strength and reduced durability during long-term transportation and rapid solidification.
A dormant-awakening agent is used, which consists of sucrose and water, and the awakening agent consists of aluminum sulfate and calcium formate. By adding an appropriate amount of dormant to cement concrete, the hydration and crystallization process of cement is slowed down and solidification is slowed down; when it is necessary to continue to use, the awakening agent is added to significantly reduce the initial settling time and improve construction performance and early and late strength.
It effectively extends the working performance maintenance time of concrete, solves the problems of long-term transportation and rapid solidification, improves the early and later strength of concrete, and enhances the flexibility of the construction process.
Smart Images
Figure CN119638252A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of mortar and concrete admixtures, and in particular to the preparation of a dormant-awakening agent for mortar and concrete and a method for using the same. Background Art
[0002] In recent years, the commercial concrete industry has flourished, but fresh cement concrete faces limitations in usage time and transportation distance. Normally, the concrete transportation time is 1-2 hours, which makes it impossible to achieve long-term and long-distance pouring. In ordinary concrete construction, unexpected situations often lead to long construction interruptions, and the slump of fresh concrete is damaged, resulting in pouring problems. It is usually necessary to add water or admixtures on site to increase the slump, but this will lead to problems such as concrete separation, prolonged setting time and reduced strength. The pouring of ultra-large volume concrete requires not only extending the setting time of concrete and reducing the heat of hydration, but also extending the time to maintain working performance to ensure the pouring quality. For conventional retarders, as the amount added increases, although it can extend the setting time of concrete or even prevent solidification, it cannot keep the working performance of fresh concrete for a longer time. If the amount added is too large, it will seriously damage the strength and durability of concrete. Summary of the invention
[0003] In view of this, in order to solve the problems faced by the cement concrete industry, the present invention proposes a dormant-awakening agent that can be used for mortar and concrete, which has an ultra-long workability retention time and effectively solves the problems faced by freshly mixed cement concrete during long-term transportation, rapid solidification and placement, such as slump loss, stacking of construction waste, reduced concrete strength and reduced durability.
[0004] In order to achieve the above object, the present invention adopts the following technical solution:
[0005] A dormancy-awakening agent for mortar and concrete, wherein the dormancy agent consists of sucrose and water; the awakening agent consists of aluminum sulfate and calcium formate.
[0006] Furthermore, the dormancy agent is composed of the following substances by mass percentage: 0.05% to 0.2% sucrose, and the balance is water; the preparation method comprises: adding appropriate amounts of water and sucrose raw materials to a container in sequence, and then stirring evenly until the sucrose is fully dissolved in the water to form a sucrose solution.
[0007] Furthermore, the awakening agent is composed of the following substances by mass percentage: 1% to 4% aluminum sulfate, 1% to 3% calcium formate, and the balance is water.
[0008] Furthermore, the dosage of the dormant agent and the awakening agent is based on the mass percentage of cement, the dosage of the dormant agent is 0.05% to 0.2%, and the dosage of the awakening agent is 2% to 7%.
[0009] Another object of the present invention is to provide a method for using the above-mentioned dormancy-awakening agent: add a dormancy agent in an amount of 0.05% to 0.2% based on the mass percentage of cement to freshly mixed mortar or concrete, stir and homogenize, so that the mortar or concrete enters a dormant state, and the dormancy effect is controlled by adjusting the amount of the dormancy agent; when the mortar or concrete needs to be continued to be used, add an awakening agent in an amount of 2% to 7% based on the mass percentage of cement to the dormant mortar or concrete, stir and homogenize, so that the mortar or concrete can be awakened, and the awakening effect can be controlled by adjusting the amount of the awakening agent.
[0010] It can be seen from the above technical solution that compared with the prior art, the present invention has the following beneficial effects:
[0011] 1. The dormant agent provided by the present invention can inhibit the hydration and crystallization process of cement, thereby slowing down solidification, solving the problems of long-distance transportation and too fast solidification. The preparation process is simple, the cost and energy consumption of the selected materials are low, the process is clear, and it is suitable for industrial production.
[0012] 2. The dormant material sucrose provided by the present invention has polarity on the cement surface and can be better adsorbed on the surface of cement particles. By destroying the calcium carbonate crystal nuclei in formation, the hydration process of cement is hindered, the mutual contact between crystals is reduced, the structure formation process is changed, and the Ca in the liquid phase at the initial stage of hydration is controlled. 2+ concentration, thus producing a retarding effect.
[0013] 3. The awakening agent provided by the present invention can significantly reduce the initial setting time of slow-setting mortar and concrete, thereby improving their construction performance and enhancing early and late strength.
[0014] 4. Combining slow setting and fast setting as a functional method of "sleeping" and "awakening" to enhance the significant flexibility of the construction process. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.
[0016] Figure 1 is a graph showing the setting time of cement paste used in the reference group and the examples of the present invention;
[0017] Figure 2 It is a data graph of the compressive strength of cement mortar used in the benchmark group and the examples of the present invention. DETAILED DESCRIPTION
[0018] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0019] Benchmark Group 1
[0020] A dormancy-awakening agent for mortar and concrete and a method for using the same, comprising the following steps:
[0021] S1. According to the weight of the raw materials, weigh 1000g of cement and 2175g of sand, add them into the cement mortar mixing pot in sequence, and dry stir for 3min.
[0022] S2. Add 500g of water to the mortar and stir for 2min until it is fully uniform. Further, inject the freshly mixed mortar into a 50mm×50mm×50mm mold and place it in a constant temperature box with a humidity of 95% and a temperature of 20°C for curing.
[0023] Benchmark Group 2
[0024] A dormancy-awakening agent for mortar and concrete and a method for using the same, comprising the following steps:
[0025] S1. Weigh 500g of water and 1g of sucrose granules, then add the weighed raw materials into the solution tank in sequence, and stir evenly until the sucrose is fully dissolved in the water to obtain a sucrose solution.
[0026] S2. Weigh 1000g of cement and 2175g of sand according to the weight of the raw materials, add them into the cement mortar mixing pot in sequence, and dry stir for 3 minutes.
[0027] S3, add 500g of the prepared sucrose solution into the mortar and stir for 2 minutes until it is fully uniform. Further, inject the newly mixed mortar into a 50mm×50mm×50mm mold and place it in a constant temperature box with a humidity of 95% and a temperature of 20°C for curing.
[0028] Furthermore, the sucrose content in step S1 is 0.1% based on the mass percentage of cement.
[0029] Example 1
[0030] A dormancy-awakening agent for mortar and concrete and a method for using the same, comprising the following steps:
[0031] S1. Weigh 500g of water and 1g of sucrose granules, then add the weighed raw materials into the solution tank in sequence, and stir evenly until the sucrose is fully dissolved in the water to obtain a sucrose solution.
[0032] S2. According to the weight of the raw materials, 1000g of cement and 2175g of sand were weighed and added into the cement mortar mixing pot in sequence, and dry stirred for 3 minutes.
[0033] S3. Add 500g of the prepared sucrose solution into the mortar and stir for 2 minutes until it is fully uniform. Place it in a constant temperature box with a humidity of 95% and a temperature of 20°C for curing for 12 hours.
[0034] S4. Add 20g of aluminum sulfate and 10g of calcium formate according to the weight of cement to the mortar that has been cured for 12h and continue stirring for 4min. Further, inject the newly mixed mortar into a 50mm×50mm×50mm mold and place it in a constant temperature box with a humidity of 95% and a temperature of 20°C for curing.
[0035] Furthermore, the sucrose content in the step S1 is 0.1% by mass of cement.
[0036] Furthermore, the aluminum sulfate and calcium formate in step S4 are of analytical purity.
[0037] Furthermore, in the step S4, the aluminum sulfate content is 2% by weight of cement, and the calcium formate content is 1% by weight of cement.
[0038] Example 2
[0039] A dormancy-awakening agent for mortar and concrete and a method for using the same, comprising the following steps:
[0040] S1. Weigh 500g of water and 1g of sucrose granules, then add the weighed raw materials into the solution tank in sequence, and stir evenly until the sucrose is fully dissolved in the water to obtain a sucrose solution.
[0041] S2. According to the weight of the raw materials, 1000g of cement and 2175g of sand were weighed and added into the cement mortar mixing pot in sequence, and dry stirred for 3 minutes.
[0042] S3. Add 500g of the prepared sucrose solution into the mortar and stir for 2 minutes until it is fully uniform. Place it in a constant temperature box with a humidity of 95% and a temperature of 20°C for curing for 12 hours.
[0043] S4. Add 20g of aluminum sulfate and 15g of calcium formate according to the weight of cement to the mortar that has been cured for 12h and continue stirring for 4min. Further, inject the newly mixed mortar into a 50mm×50mm×50mm mold and place it in a constant temperature box with a humidity of 95% and a temperature of 20°C for curing.
[0044] Furthermore, the sucrose content in the step S1 is 0.1% by mass of cement.
[0045] Furthermore, the aluminum sulfate and calcium formate in step S4 are of analytical purity.
[0046] Furthermore, in the step S4, the amount of aluminum sulfate added is 2% by weight of cement, and the amount of calcium formate added is 1.5% by weight of cement.
[0047] Example 3
[0048] A dormancy-awakening agent for mortar and concrete and a method for using the same, comprising the following steps:
[0049] S1. Weigh 500g of water and 1g of sucrose granules, then add the weighed raw materials into the solution tank in sequence, and stir evenly until the sucrose is fully dissolved in the water to obtain a sucrose solution.
[0050] S2. According to the weight of the raw materials, 1000g of cement and 2175g of sand were weighed and added into the cement mortar mixing pot in sequence, and dry stirred for 3 minutes.
[0051] S3. Add 500g of the prepared sucrose solution into the mortar and stir for 2 minutes until it is fully uniform. Place it in a constant temperature box with a humidity of 95% and a temperature of 20°C for curing for 12 hours.
[0052] S4. Add 25g aluminum sulfate and 10g calcium formate according to the weight of cement to the mortar that has been cured for 12h and continue stirring for 4min. Further, inject the newly mixed mortar into a 50mm×50mm×50mm mold and place it in a constant temperature box with a humidity of 95% and a temperature of 20°C for curing.
[0053] Furthermore, the sucrose content in the step S1 is 0.1% by mass of cement.
[0054] Furthermore, the aluminum sulfate and calcium formate in step S4 are of analytical purity.
[0055] Furthermore, in the step S4, the aluminum sulfate content is 2.5% by weight of cement, and the calcium formate content is 1% by weight of cement.
[0056] Example 4
[0057] A dormancy-awakening agent for mortar and concrete and a method for using the same, comprising the following steps:
[0058] S1. Weigh 500g of water and 1g of sucrose granules, then add the weighed raw materials into the solution tank in sequence, and stir evenly until the sucrose is fully dissolved in the water to obtain a sucrose solution.
[0059] S2. According to the weight of the raw materials, 1000g of cement and 2175g of sand were weighed and added into the cement mortar mixing pot in sequence, and dry stirred for 3 minutes.
[0060] S3. Add 500g of the prepared sucrose solution into the mortar and stir for 2 minutes until it is fully uniform. Place it in a constant temperature box with a humidity of 95% and a temperature of 20°C for curing for 12 hours.
[0061] S4. Add 25g of aluminum sulfate and 15g of calcium formate according to the weight of cement to the mortar that has been cured for 12h and continue stirring for 4min. Further, inject the newly mixed mortar into a 50mm×50mm×50mm mold and place it in a constant temperature box with a humidity of 95% and a temperature of 20°C for curing.
[0062] Furthermore, the sucrose content in the step S1 is 0.1% by mass of cement.
[0063] Furthermore, the aluminum sulfate and calcium formate in step S4 are of analytical purity.
[0064] Furthermore, in the step S4, the amount of aluminum sulfate added is 2.5% by weight of cement, and the amount of calcium formate added is 1.5% by weight of cement.
[0065] The above-mentioned Examples 1 to 4 were subjected to performance tests, mainly testing the setting time and compressive strength, wherein the setting time test standard was tested according to GB1346-2011 "Test Method for Water Consistency, Setting Time and Stability of Cement Standard Consistency", and the compressive strength was tested according to GB50107 "Concrete Strength Test and Evaluation Standard".
[0066] Table 1 Proportions of cement mortar and pure paste (without sand) mixture
[0067]
[0068] Table 2 Setting time and compressive strength test results
[0069]
[0070] According to the setting time and compressive strength test results in Table 2, the initial setting and final setting times of the clean slurry of the reference group 2, which added a dormant agent but no awakening agent, were significantly prolonged, about 5 times that of the clean slurry of the reference group 1 without adding a dormant agent. In the clean slurries of Examples 1 to 4, which added a dormant agent and an awakening agent, the initial setting time and the final setting time were not much different from those of the reference group 1.
[0071] The specific data are as follows:
[0072] The compressive strength of the benchmark group 2 and examples 1 to 4 at 1 day age is almost not large. This is because the addition of calcium formate and aluminum sulfate promotes the rapid crystallization of Ca(OH)2 to saturation, which makes the cement coagulate, but does not provide strength. Aluminum sulfate and calcium formate improve the strength of the sucrose cement mortar to a certain extent, but the increase is not large. The compressive strength at 3 days is 14.88MPa, and the compressive strength at 28 days is increased by 0.8%. In contrast, the compressive strength of the mortars of examples 1 to 4 at 3 days age is increased by 19.1%, 21%, 8.7% and 9.9%, respectively, at 7 days age, by 20.4%, 25.8%, 16.4% and 14.5%, respectively, and at 28 days, by 11.7%, 18.3%, 19.5% and 5.9%, respectively, showing a significant improvement compared with the benchmark group 1.
[0073] This is mainly because the sucrose solution can first adsorb sucrose on the aluminate phase, inhibiting the hydration of C3S and the generation of AFt. The hydration product AFt will cover and wrap the surface of cement particles, thereby preventing further hydration of cement and inhibiting the formation and growth of CH crystals, thus achieving a retarding effect. Adding calcium formate to the dormant agent can increase the Ca in the liquid phase. 2+ The concentration of C3S can dissolve quickly, and at the same time promote the crystallization of Ca(OH)2, which helps the Ca(OH)2 precipitation in the solution to transform into a solid phase, increase the solid phase of the cement paste, and then promote the solidification. Aluminum sulfate can promote the hydration of C3A in the early stage of cement hydration and the large-scale generation of AFt, thereby promoting the coagulation and hardening of the sucrose-added cement paste. In the initial stage of the structure formation of the cement paste, there is enough CSH gel to fill the skeleton structure built by AFt, making the cement stone structure more compact and improving the early strength of the cement mortar with dormant agent.
[0074] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.
[0075] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.
Claims
1. A dormancy-awakening agent for mortar and concrete, characterized in that: The dormant agent consists of sucrose and water; the awakening agent consists of aluminum sulfate and calcium formate.
2. A dormancy-awakening agent for mortar and concrete according to claim 1, characterized in that: The dormancy agent is composed of the following substances by mass percentage: 0.05% to 0.2% sucrose and the balance is water. The preparation method comprises: adding appropriate amounts of water and sucrose raw materials to a container in sequence, and then stirring evenly until the sucrose is fully dissolved in the water to form a sucrose solution.
3. A dormancy-awakening agent for mortar and concrete according to claim 1, characterized in that: The awakening agent is composed of the following substances by mass percentage: 1% to 4% aluminum sulfate, 1% to 3% calcium formate, and the balance is water.
4. A dormancy-awakening agent for mortar and concrete according to claim 1, characterized in that: The dosage of the dormant agent and the awakening agent is based on the mass percentage of cement, the dosage of the dormant agent is 0.05% to 0.2%, and the dosage of the awakening agent is 2% to 7%.
5. The method for using the sleep-awakening agent according to claim 1, characterized in that: Add a dormant agent in an amount of 0.05% to 0.2% based on the mass percentage of cement to the newly mixed mortar or concrete, stir and homogenize, so that the mortar or concrete enters a dormant state, and the dormant effect is controlled by adjusting the dosage of the dormant agent; when the mortar or concrete needs to be continued to be used, add an awakening agent in an amount of 2% to 7% based on the mass percentage of cement to the dormant mortar or concrete, stir and homogenize, and the mortar or concrete can be awakened, and the awakening effect can be controlled by adjusting the dosage of the awakening agent.