Method for measuring setting time of recycled water of concrete mixing plant

Abstract

The invention relates to a method for measuring the setting time of recycled water of a concrete mixing plant, which comprises the following steps of: performing constant-temperature and constant-humidity curing on the recycled water of the concrete mixing plant, starting timing when the recycled water is put into a curing box, placing the recycled water of the concrete mixing plant in an environment with 6-8 standard atmospheric pressures after curing is completed, and determining the setting time of the recycled water of the concrete mixing plant. And when a non-strength block appears in the recycled water of the concrete mixing plant, obtaining the time when the recycled water of the concrete mixing plant starts to condense. The technical problem to be solved by the invention is to test the recycled water condensation time of the concrete mixing plant through an air compression method, so that an observation result is more direct.

Description

Technical Field

[0001] The invention belongs to the technical field of concrete, and in particular relates to a method for determining the coagulation time of recycled water in a concrete mixing station. Background Art

[0002] The components of recycled water in concrete mixing plants include CSH gel, calcium sulfonate, chemical admixtures, mineral admixtures that do not participate in the reaction, unhydrated cement particles, and impurities such as silt, gravel, and mineral powder brought in for various reasons. The composition is complex, but its main component is the product of cement hydration. Therefore, when testing the setting time, the main focus is on cement. Cement setting time test method: GB / T 1346-2011, the time required for a test needle to sink into a certain depth of cement standard consistency pure paste; Standard for test methods for performance of ordinary concrete mixtures, GB / T 50080-2002;

[0003] T0505-2020 Test method for water consumption, setting time and stability of cement at standard consistency. Currently, there is no related prior art for the determination of setting time of recycled water in concrete mixing plants. Summary of the invention

[0004] In view of this, the main purpose of the present invention is to provide a method for determining the coagulation time of water recovered in a concrete mixing station. The technical problem to be solved is to test the coagulation time of water recovered in a concrete mixing station by an air compression method so that the observation result is more direct.

[0005] The purpose of the present invention and the technical problem to be solved are achieved by adopting the following technical solutions. A method for determining the setting time of recycled water in a concrete mixing station proposed by the present invention comprises the following steps:

[0006] The recycled water from the concrete mixing station is subjected to constant temperature and humidity curing. The timing starts when the water is placed in the curing box. After the curing is completed, the recycled water from the concrete mixing station is placed in an environment of 6-8 standard atmospheric pressures. The timing is stopped when a strengthless block appears in the recycled water from the concrete mixing station. The time when the recycled water from the concrete mixing station starts to coagulate can be obtained.

[0007] The purpose of the present invention and the technical problems to be solved can be further achieved by adopting the following technical measures.

[0008] Preferably, in the aforementioned method for determining the setting time of recycled water in a concrete mixing station, the constant temperature and humidity curing conditions are: temperature 18-22°C, humidity>95%, and time 6-8h.

[0009] Preferably, in the aforementioned method for determining the setting time of recycled water from a concrete mixing station, the concentration of the recycled water from the concrete mixing station is 7wt%-20wt%.

[0010] Preferably, in the aforementioned method for determining the setting time of recycled water from a concrete mixing station, the concentration of the recycled water from the concrete mixing station is 7wt%, and the corresponding curing time is 8h.

[0011] Preferably, in the aforementioned method for determining the setting time of recycled water from a concrete mixing station, the concentration of the recycled water from the concrete mixing station is 10wt%, and the corresponding curing time is 7.5h.

[0012] Preferably, in the aforementioned method for determining the setting time of recycled water from a concrete mixing station, the concentration of the recycled water from the concrete mixing station is 12 wt %, and the corresponding curing time is 7 h.

[0013] Preferably, in the aforementioned method for determining the setting time of recycled water from a concrete mixing station, the concentration of the recycled water from the concrete mixing station is 15wt%, and the corresponding curing time is 6.5h.

[0014] Preferably, in the aforementioned method for determining the setting time of recycled water from a concrete mixing station, the concentration of the recycled water from the concrete mixing station is 20wt%, and the corresponding curing time is 6h.

[0015] Preferably, in the aforementioned method for determining the setting time of recycled water from a concrete mixing station, the solid components of the recycled water from the concrete mixing station are composed by weight percentage: the solid components are composed by mass percentage: silicon oxide 30-40%; calcium oxide 6-12%; iron oxide 2-4%; aluminum oxide 28-38%; magnesium oxide 2-4%; loss on ignition 12-18%; and others 0.5-1.5%.

[0016] Preferably, in the aforementioned method for determining the setting time of recycled water from a concrete mixing station, the solid components of the recycled water from the concrete mixing station are composed by weight percentage as follows: 35.1% silicon oxide; 9.8% calcium oxide; 3.1% iron oxide; 32.5% aluminum oxide; 2.9% magnesium oxide; 15.4% loss on ignition; and 1.2% others.

[0017] Compared with the prior art, the method for determining the setting time of recycled water in a concrete mixing station according to the present invention has the following beneficial effects:

[0018] The present invention tests the setting time of recycled water in a concrete mixing station by an air pressure method, does not touch the slurry below, uses air pressure to blow up the slurry, and observes the state, so that the observation result is more direct. The test method is concise, clear, operable, repeatable, and can measure the specific value of the setting time.

[0019] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the preferred embodiments of the present invention are described in detail as follows. DETAILED DESCRIPTION

[0020] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following is a detailed description of the specific implementation method, structure, characteristics and effects of a method for determining the coagulation time of recycled water in a concrete mixing station proposed by the present invention in combination with a preferred embodiment. In the following description, different "one embodiment" or "embodiment" does not necessarily refer to the same embodiment. In addition, specific features, structures or characteristics in one or more embodiments may be combined in any suitable form.

[0021] Unless otherwise specified, the materials, reagents, etc. involved below are all commercially available products well known to those skilled in the art; unless otherwise specified, the methods described are all methods known in the art. Unless otherwise defined, the technical terms or scientific terms used should have the usual meanings understood by ordinary technicians in the field to which the present invention belongs. If no specific experimental steps or conditions are specified below, the operations or conditions of the conventional experimental steps described in the literature in the field can be followed.

[0022] Some embodiments of the present invention provide a method for determining the setting time of recycled water in a concrete mixing plant, comprising the following steps:

[0023] The recycled water from the concrete mixing station is maintained at a constant temperature and humidity. The time is started when it is placed in the curing box. After the curing is completed, the recycled water from the concrete mixing station is placed in an environment of 6-8 standard atmospheric pressures. The time is stopped when the recycled water from the concrete mixing station has a block without strength. The time when the recycled water from the concrete mixing station begins to condense can be obtained. If the air pressure is higher than 8 standard atmospheric pressures, the solid part in the recycled water will be blown away; if the air pressure is lower than 6 standard atmospheric pressures, the air pressure is too low and the solid part cannot be blown away, which will affect the test results.

[0024] In some embodiments, considering the instability of the temperature and humidity in the laboratory and indoor environment, a curing box is used to maintain constant temperature and humidity to reduce environmental errors; optionally, the conditions for constant temperature and humidity curing are: temperature 18-22°C, humidity>95%, and time 6-8h. If the temperature is set below 18°C, the temperature is too low, the condensation time is prolonged, and the experimental results are affected; if the temperature is higher than 22°C, the temperature is too high, the condensation time is shortened, and the experimental results are affected.

[0025] In some embodiments, optionally, the concentration of the recycled water from the concrete mixing station is 7wt%-20wt%. For example, the concentration of the recycled water from the concrete mixing station can be 7wt%, 10wt%, 12wt%, 15wt% or 20wt%, and the corresponding curing time is 8h, 7.5h, 7h, 6.5h or 6h, respectively. The main component of the recycled water from the concrete mixing station is the product of cement hydration, and the setting time of cement varies greatly under different temperature and humidity environments. Putting it into a constant temperature and humidity curing box for curing can unify the temperature and humidity, make the curing environment tend to be consistent, and reduce errors. If the concentration is lower than 7wt%, the setting time will be extended; if the concentration is higher than 20wt%, the setting time will be shortened.

[0026] In some embodiments, optionally, the recycled water of the concrete mixing station includes CSH gel, a product of cement hydration, calcium sulfoxide, chemical admixtures, mineral admixtures not involved in the reaction, unhydrated cement particles, and impurities such as silt, gravel, and mineral powder introduced for various reasons; its solid components are composed of 30-40% silicon oxide, 6-12% calcium oxide, 2-4% iron oxide, 28-38% aluminum oxide, 2-4% magnesium oxide, 12-18% loss on ignition, and 0.5-1.5% others; for example, the solid components of the recycled water of the concrete mixing station are composed of 35.1% silicon oxide, 9.8% calcium oxide, 3.1% iron oxide, 32.5% aluminum oxide, 2.9% magnesium oxide, 15.4% loss on ignition, and 1.2% others. "Others" are substances that cannot be measured by instruments.

[0027] In specific implementation, the determination method comprises the following steps:

[0028] The recycled water from the concrete mixing station is stored in a transparent container with a size of 10×12cm (diameter×height). This size is easy to operate and does not take up too much space. The transparent container is made of high-quality plastic material and has good transparency, so that the state of the recycled water in the container can be clearly seen from the appearance; then the container containing the recycled water is placed in a YH-40B standard constant temperature and humidity curing box for constant temperature and humidity curing. This setting is to provide a stable and suitable curing environment for the recycled water. It can accurately control the temperature fluctuation within a certain range to ensure that the recycled water will not change its properties due to temperature changes; at the same time, it can also maintain the humidity at a reasonable level to prevent the recycled water from excessive evaporation or absorption of too much water, so as to ensure that it can maintain a stable state under specific environmental conditions; when the container containing the recycled water from the concrete mixing station is placed in the curing box, the timing starts at h1. After the curing is completed, take out the container and connect the oil-free air compressor to the container containing the recycled water through a hose , and the hose is tightly fitted on the wall of a cylindrical container with a size of 10×12cm (diameter×height), and operated at 6-8 standard atmospheric pressures at a distance of 1-1.5cm from the container wall (the oil-free air compressor comes with a spray gun, but the spray gun has a shorter blowing port, so the connecting hose is put on the spray gun. During operation, the hose is placed along the wall of the container containing recycled water, and operated at a distance of 1-1.5cm. If it is higher than 1.5cm, the blowing port is far away from the slurry part in the recycled water and cannot be blown well. If it is lower than 1cm, the blowing port is too close to the slurry part in the recycled water, and it may touch the bottom slurry due to improper operation, resulting in excessive error). If no block is blown up during the operation, it can be judged that the recycled water is in an uncondensed state at this time; if a block without strength appears during the operation, the time recorded at this time is h2. Finally, by calculating the difference between h2 and h1, the time when the recycled water begins to condense can be obtained. 6-8 standard atmospheres can effectively blow up the slurry of recovered water. If it is lower than 6 standard atmospheres, the air pressure is too small to blow up the slurry; if it is higher than 8 standard atmospheres, the air pressure is too high and will disperse the slurry, which is not conducive to observing the test results.

[0029] The present invention will be further described below in conjunction with specific embodiments, but this should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made to the present invention by technicians in this field based on the above-mentioned contents of the present invention still fall within the scope of protection of the present invention.

[0030] Example 1

[0031] Test on the setting time of recycled water from a concrete mixing station with a concentration of 7wt%: 500g of recycled water with a concentration of 7wt% was weighed from a concrete mixing station production line in Beijing and placed in a cylindrical container with a size of 10×12cm (diameter×height). The container was placed in a constant temperature and humidity curing box for curing at a temperature of 20°C and a humidity of 98%. The curing time was 8h. The timing started when the container was placed in the curing box and the recorded time was h1. After the curing was completed, an oil-free air compressor was used to operate the oil-free air compressor. The air pressure of the oil air compressor is set to 6 standard atmospheres. A hose is connected to the blowhole of the spray gun of the oil-free air compressor, and the hose is placed close to the container wall. The operation is performed at a distance of 1 cm from the container wall. After blowing out weak blocks with particle sizes of 2 cm, 3 cm, 4 cm, 5 cm, and 6 cm (they can be moved by lightly touching them with a glass rod, but the blocks are not loose), the time is recorded as h2. Using h2-h1, the condensation time of recovered water with a concentration of 7wt% can be obtained, which is 8.5h.

[0032] Example 2

[0033] Test of setting time of recycled water from a concrete mixing station with a concentration of 10wt%: 500g of recycled water with a concentration of 10wt% was weighed from a concrete mixing station production line in Beijing and placed in a cylindrical container with a size of 10×12cm (diameter×height). The container was placed in a constant temperature and humidity curing box for curing at a temperature of 20°C and a humidity of 98%. The curing time was 7.5h. The timing started when the container was placed in the curing box and the recorded time was h1. An oil-free air compressor was used to operate the container. The air pressure of the oil-free air compressor is set to 6 standard atmospheres. A hose is connected to the blowhole of the spray gun of the oil-free air compressor, and the hose is placed close to the container wall. The operation is performed at a distance of 1 cm from the container wall. After blowing out blocks with no strength of 2 cm, 3 cm, 4 cm, 5 cm, and 6 cm in size (gently touch them with a glass rod, they can be moved, but the blocks are not loose), the time is recorded as h2. Using h2-h1, the condensation time of recycled water with a concentration of 10wt% can be obtained, which is 8h.

[0034] Example 3

[0035] The setting time test of recycled water from a concrete mixing station with a concentration of 12wt% was as follows: 500g of recycled water with a concentration of 12wt% was weighed from a production line of a concrete mixing station in Beijing, and placed in a cylindrical container with a size of 10×12cm (diameter×height). The container was placed in a constant temperature and humidity curing box for curing at a temperature of 20°C and a humidity of 98%. The curing time was 7h. The timing started when the container was placed in the curing box, and the recorded time was h1. An oil-free air compressor was used to operate the oil-free air compressor. The air pressure is set to 6 standard atmospheres, a hose is connected to the blowhole of the spray gun of the oil-free air compressor, and the hose is placed close to the container wall. The operation is performed at a distance of 1 cm from the container wall. After blowing out small pieces of no strength with particle sizes of 2 cm, 3 cm, 4 cm, 5 cm, and 6 cm (they can be moved by lightly touching them with a glass rod, but the pieces are not loose), the time is recorded as h2. Using h2-h1, the condensation time of recovered water with a concentration of 12 wt% can be obtained, which is 7.5 h.

[0036] Example 4

[0037] Test of setting time of recycled water from a concrete mixing station with a concentration of 15wt%: 500g of recycled water with a concentration of 15wt% was weighed from a concrete mixing station production line in Beijing and placed in a cylindrical container with a size of 10×12cm (diameter×height). The container was placed in a constant temperature and humidity curing box for curing at a temperature of 20°C and a humidity of 98%. The curing time was 6.5h. The timing started when the container was placed in the curing box and the recorded time was h1. An oil-free air compressor was used to operate the oil-free air compressor. The air pressure of the oil air compressor is set to 6 standard atmospheres. A hose is connected to the blowhole of the spray gun of the oil-free air compressor, and the hose is placed close to the container wall. The operation is performed at a distance of 1 cm from the container wall. After blowing out small pieces of no strength with particle sizes of 2 cm, 3 cm, 4 cm, 5 cm, and 6 cm (they can be moved by lightly touching them with a glass rod, but the pieces are not loose), the time is recorded as h2. Using h2-h1, the condensation time of recovered water with a concentration of 15 wt% can be obtained, which is 7 h.

[0038] Example 5

[0039] Test of setting time of recycled water from a concrete mixing station with a concentration of 20wt%: 500g of recycled water with a concentration of 20wt% was weighed from a concrete mixing station production line in Beijing and placed in a cylindrical container with a size of 10×12cm (diameter×height). The container was placed in a constant temperature and humidity curing box for curing at a temperature of 20℃ and a humidity of 98%. The curing time was 6h. The timing started when the container was placed in the curing box and the recorded time was h1. An oil-free air compressor was used to operate the oil-free air compressor. The air pressure of the air compressor is set to 6 standard atmospheres. A hose is connected to the blowhole of the spray gun of the oil-free air compressor, and the hose is placed close to the container wall. The operation is performed at a distance of 1 cm from the container wall. After blowing out small pieces of weak strength with particle sizes of 2 cm, 3 cm, 4 cm, 5 cm, and 6 cm (they can be moved by lightly touching them with a glass rod, but the pieces are not loose), the time is recorded as h2. Using h2-h1, the condensation time of recycled water with a concentration of 20% can be obtained, which is 6.5 h.

[0040] It can be seen from the data of Examples 1-5 that the testing method of the present invention can intuitively measure the setting time of recycled water in a concrete mixing station. As the concentration of recycled water increases, the setting time gradually decreases from 8.5 h to 6.5 h.

[0041] In the specification of the present invention, a lot of specific details are described. However, it is understood that embodiments of the present invention can be practiced without these specific details. In some embodiments, well-known methods, structures and techniques are not shown in detail so as not to obscure the understanding of this specification.

[0042] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0043] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

[0044] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A method for determining the setting time of recycled water in a concrete mixing station, characterized in that: The following steps are involved: The recycled water from the concrete mixing station is subjected to constant temperature and humidity curing. The timing starts when the water is placed in the curing box. After the curing is completed, the recycled water from the concrete mixing station is placed in an environment of 6-8 standard atmospheric pressures. The timing is stopped when a strengthless block appears in the recycled water from the concrete mixing station. The time when the recycled water from the concrete mixing station starts to coagulate can be obtained.

2. The method for determining the setting time of recovered water in a concrete mixing station according to claim 1, characterized in that: The constant temperature and humidity curing conditions are: temperature 18-22°C, humidity>95%, and time 6-8h.

3. The method for determining the setting time of recovered water in a concrete mixing station according to claim 1, characterized in that: The concentration of the recycled water in the concrete mixing station is 7wt%-20wt%.

4. The method for determining the setting time of recovered water in a concrete mixing station according to claim 3, characterized in that: The concentration of recycled water in the concrete mixing station is 7wt%, and the corresponding curing time is 8h.

5. The method for determining the setting time of recovered water in a concrete mixing station according to claim 3, characterized in that: The concentration of recycled water in the concrete mixing station is 10wt%, and the corresponding curing time is 7.5h.

6. The method for determining the setting time of recovered water in a concrete mixing plant according to claim 3, characterized in that: The concentration of recycled water from the concrete mixing station is 12 wt %, and the corresponding curing time is 7 h.

7. The method for determining the setting time of recovered water in a concrete mixing station according to claim 3, characterized in that: The concentration of recycled water in the concrete mixing station is 15wt%, and the corresponding curing time is 6.5h.

8. The method for determining the setting time of recovered water in a concrete mixing station according to claim 3, characterized in that: The concentration of recycled water in the concrete mixing station is 20wt%, and the corresponding curing time is 6h.

9. The method for determining the setting time of recovered water in a concrete mixing station according to claim 1, characterized in that: The solid components of the recycled water are composed of: 30-40% silicon oxide, 6-12% calcium oxide, 2-4% iron oxide, 28-38% aluminum oxide, 2-4% magnesium oxide, 12-18% loss on ignition, and 0.5-1.5% others.

10. The method for determining the setting time of recovered water in a concrete mixing station according to claim 9, characterized in that: The solid components of the recycled water are composed of 35.1% silicon oxide, 9.8% calcium oxide, 3.1% iron oxide, 32.5% aluminum oxide, 2.9% magnesium oxide, 15.4% loss on ignition, and 1.2% others in terms of weight percentage.