Cement-based retardant mortar test block and method of making same

Abstract

Cement-based retarding mortar test mold and preparation method thereof, relate to the technical field of retarding mortar test mold, and particularly relate to a cement-based retarding mortar test mold and a preparation method thereof.The cement-based retarding mortar test mold comprises a test mold main body, the test mold main body is a cement-based test mold, the compressive strength value is 155-170 MPa, and a test groove is arranged in the test mold main body; the inner surface of the test groove is sprayed with a composite aqueous solution of sodium silicate, magnesium fluorosilicate and potassium fluorosilicate for surface treatment, and the spraying ratio is that the mass ratio of sodium silicate, magnesium fluorosilicate, potassium fluorosilicate and deionized water is (2.9-3.1) :(1.9-2.1) :(0.9-1.1) :(3.9-4.1). The cement-based retarding mortar test mold has the positive effect that the test data in a laboratory can be matched with the field construction data, and production enterprises can adjust the mixing ratio in time according to the field construction to improve the engineering quality.

Description

Technical Field

[0001] This invention relates to the field of retarded mortar test mold technology, and in particular to a cement-based retarded mortar test mold and its preparation method. Background Technology

[0002] Retarded mortar is one of the most important interior decoration materials. Compared with ordinary mortar, it has a longer setting time, making it easier to pre-mix for long-distance transportation and facilitating construction. For example... Figure 3 As shown, in practical construction applications, retarded mortar comes into contact with other cement-based materials, resulting in physical phenomena such as heat and moisture exchange. This leads to rapid early strength development, with the surface typically hardening within one day. However, in laboratory tests, when retarded mortar is molded in conventional plastic or cast steel molds and tested for strength after 3 and 7 days of hydration, the test blocks are not fully hardened, exhibiting low strength and difficulty in demolding. Therefore, it is difficult to evaluate the early performance of laboratory test blocks, making it difficult to match laboratory test data with on-site construction data. Consequently, if problems arise with the retarded mortar in practical applications, manufacturers cannot promptly adjust the mix proportions to improve project quality. Summary of the Invention

[0003] The purpose of this invention is to provide a cement-based retarded mortar test mold to match laboratory test data with on-site construction data, enabling production enterprises to adjust the mix ratio in a timely manner according to on-site construction to improve project quality.

[0004] The cement-based retarded mortar test mold provided by the present invention includes a test mold body, wherein the test mold body is a cement-based test mold with a compressive strength of 155-170 MPa, and a test groove is provided inside; the inner surface of the test groove is sprayed with a composite aqueous solution of sodium silicate hydrate, magnesium fluorosilicate and potassium fluorosilicate for surface treatment, and the spraying ratio by mass is sodium silicate hydrate: magnesium fluorosilicate: potassium fluorosilicate: deionized water of (2.9-3.1): (1.9-2.1): (0.9-1.1): (3.9-4.1).

[0005] Furthermore, the main body of the test mold is a cubic structure of 150mm×150mm×150mm, and its interior is provided with a cubic test groove of 70.7mm×70.7mm×70.7mm.

[0006] Furthermore, each cubic meter of the test mold body contains the following components by mass:

[0007] Cement (PO 52.5): 596~605, fly ash: 96~104, quartz sand: 1196~1204, silica fume: 296~304, water-reducing agent: 30~40, copper-plated steel fiber: 152~158.

[0008] Furthermore, each cubic meter of the test mold body (1) contains the following components by mass:

[0009] Cement (PO 52.5): 600, fly ash: 100, quartz sand: 1200, silica fume: 300, water-reducing agent: 35-40, copper-plated steel fiber: 156.

[0010] The method for preparing cement-based retarded mortar test molds provided by this invention includes the following steps:

[0011] Step 1, Prepare the mold for cement-based retarded mortar test:

[0012] Plaster-based core mold test blocks were prepared by mixing gypsum powder and water at a water / solid ratio of 0.76 to 0.78. The gypsum core molds were dried and taken out for later use.

[0013] Apply machine oil evenly to the inner surface of the plastic mold and let it stand for later use.

[0014] After placing the plaster core mold inside the plastic test mold, fix the plaster core mold and the plastic test mold to make a cement-based retarded mortar test mold for later use.

[0015] Step 2, prepare cement-based retarded mortar test molds:

[0016] Each cubic meter of the test mold body contains the following components by mass:

[0017] Cement (PO 52.5): 596~605, fly ash: 96~104, quartz sand: 1196~1204, silica fume: 296~304, water reducing agent: 30~40, copper-plated steel fiber: 152~158;

[0018] After mixing, pour it into the cement-based retarded mortar test mold from step 1;

[0019] Step 3: After curing the cement-based retarded mortar test mold from Step 2, remove the plastic test mold to obtain the main body of the test mold.

[0020] Step 4: After steam curing the main body of the test mold from Step 3, remove the plaster core mold inside the main body of the test mold to make the test groove;

[0021] Step 5: Spray a composite aqueous solution of sodium silicate hydrate, magnesium fluorosilicate and potassium fluorosilicate onto the inner surface of the test groove in Step 4 for surface treatment. The spraying ratio is sodium silicate hydrate: magnesium fluorosilicate: potassium fluorosilicate: deionized water in a mass ratio of 3:2:1:4 to prepare a cement-based retarded mortar test mold.

[0022] Further, in step 1, a gypsum-based core mold test block with dimensions of 70.7mm × 70.7mm × 70.7mm is prepared. First, 760g of water is placed in a mixing pot, and 1000g of gypsum powder is added. The mixture is stirred for 60s to 70s until a uniform slurry is formed. Then, the slurry is poured into a 70.7mm × 70.7mm × 70.7mm plastic mold, the surface is smoothed, and the mold is left to stand at room temperature (24±1℃) for 2 hours before being removed. The mold is then placed in a forced-air drying oven and dried at 40±1℃ for 5 to 5.5 hours before being taken out for use.

[0023] After placing the plaster core mold inside the plastic test mold, cut four plastic tubes with a length of 39.7 to 39.9 mm to support it inside the plastic test mold, ensuring that the plaster core mold is located in the center of the plastic test mold.

[0024] Further, in step 2, cement, fly ash, quartz sand, and silica fume are added to the mixer in sequence and dry-mixed for 6 to 6.5 minutes. Then, mixing is continued for 5 to 5.5 minutes. Water and water-reducing agent are slowly added and thoroughly mixed. Copper-plated steel fibers are then evenly sprinkled in and mixing is continued for 3 to 3.5 minutes. The mixture is then poured into the cement-based retarded mortar test mold from step 1 and vibrated for 2 to 2.5 minutes using a magnetic vibration table. The surface is then smoothed.

[0025] Furthermore, in step 3, the cement-based retarded mortar test mold from step 2 is cured at a temperature of 20±2℃ and a humidity greater than 95% for 24-25 hours, and the plastic test mold is removed to obtain the main body of the test mold.

[0026] Furthermore, in step 4, after steaming and curing the main body of the test mold from step 3 at 80-85°C for 48-49 hours, it is soaked in a saturated Ca(OH)2 aqueous solution for 24-25 hours. Then, the plaster core mold inside the main body of the test mold is removed to form the test groove.

[0027] Furthermore, in step 5, the unevenness on the inner surface of the cement-based retarded mortar mold is repaired so that the inner diameter error of the cement-based retarded mortar mold is 70.7±1mm; the plastic tube used for support is filled, and the powder ratio of the filling material is cement: silica fume: fly ash: mineral powder = 6:2:1:1, and the water / solid ratio of the powder is 0.6.

[0028] The cement-based retarding mortar test mold provided by this invention has the following beneficial effects:

[0029] 1. This invention innovatively develops a cement-based test mold for slow-setting mortar into a test mold made of ultra-high performance concrete. The 3-day compressive strength value can reach more than 155MPa. It has high mechanical strength, excellent wear resistance and surface quality, and can ensure that the mold can be reused multiple times.

[0030] 2. The inner surface of the test groove of this invention is sprayed with a composite aqueous solution of sodium silicate hydrate, magnesium fluorosilicate and potassium fluorosilicate for surface treatment to ensure that the inner surface is smooth, which facilitates the molding of the test block and ensures the surface quality of the molded test block.

[0031] 3. This invention can shorten the final setting time of retarded mortar in the laboratory from 8 days to 1.5 days, greatly reducing the laboratory test cycle and improving test efficiency. At the same time, this invention can also provide more timely and accurate test data for the practical engineering application of retarded mortar.

[0032] Therefore, the present invention has the positive effect of matching laboratory test data with on-site construction data, enabling production enterprises to adjust the mix ratio in a timely manner according to on-site construction to improve project quality. Attached Figure Description

[0033] The accompanying drawings disclose specific embodiments of the present invention, wherein,

[0034] Figure 1 This is a schematic diagram of the structure of the present invention;

[0035] Figure 2 This is the condensation time diagram of the present invention;

[0036] Figure 3 This is a graph showing the difference in setting time between the retarded mortar of this invention at the construction site and in the laboratory;

[0037] Reference numerals: 1. Test mold body; 11. Test groove. Detailed Implementation

[0038] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. Example 1:

[0039] like Figure 1-2 As shown, the cement-based retarded mortar test mold provided by the present invention includes a test mold body 1, which is a cement-based test mold with a compressive strength of 155-170 MPa. The test mold body 1 has a test groove 11 inside. The inner surface of the test groove 11 is sprayed with a composite aqueous solution of sodium silicate hydrate, magnesium fluorosilicate and potassium fluorosilicate for surface treatment. The spraying ratio is sodium silicate hydrate: magnesium fluorosilicate: potassium fluorosilicate: deionized water in the ratio of (2.9-3.1): (1.9-2.1): (0.9-1.1): (3.9-4.1). Example 2:

[0040] The test mold body 1 of the present invention is a cubic structure of 150mm×150mm×150mm, and its interior is provided with a cubic test groove 11 of 70.7mm×70.7mm×70.7mm. The test groove 11 can be used to form a slow-setting mortar test block of the corresponding size.

[0041] Each cubic meter of the test mold body 1 of the present invention comprises the following components by mass:

[0042] Cement (PO 52.5): 596~605, fly ash: 96~104, quartz sand: 1196~1204, silica fume: 296~304, water-reducing agent: 30~40, copper-plated steel fiber: 152~158.

[0043] Traditional test molds for retarded mortar are mainly made of steel or plastic, which makes it difficult to simulate the moisture and heat exchange processes between the retarded mortar and the surface of cement-based materials during use. For example... Figure 2 As shown, this invention innovatively develops a cement-based mold for retarded mortar testing, made of ultra-high performance concrete. This mold possesses high mechanical strength, superior wear resistance, and excellent surface quality, ensuring multiple reuses. The inner surface of the test groove 11 is treated with a composite aqueous solution of hydrated sodium silicate, magnesium fluorosilicate, and potassium fluorosilicate to ensure a smooth inner surface for easy specimen molding and guarantee the surface quality of the molded specimens. This invention can shorten the final setting time of retarded mortar in the laboratory from 8 days to 1.5 days, significantly reducing the laboratory testing cycle and improving testing efficiency. Simultaneously, this invention can provide more timely and accurate test data for the practical engineering applications of retarded mortar. Example 3:

[0044] Each cubic meter of the test mold body 1 of the present invention comprises the following components by mass:

[0045] Cement (PO 52.5): 600, fly ash: 100, quartz sand: 1200, silica fume: 300, water-reducing agent: 35-40, copper-plated steel fiber: 156.

[0046]

[0047] The slump spread, compressive strength, and apparent quality of the test mold body 1 of this invention were tested according to relevant standards such as "Ultra-High Performance Concrete: Basic Properties and Test Methods". As shown in Table 1, the test mold body 1 of this invention has high compressive strength, with a 3-day compressive strength value exceeding 155 MPa. Furthermore, the good fluidity of the slurry effectively reduces the molding difficulty and improves the molding quality. Example 4:

[0048] The method for preparing cement-based retarded mortar test molds includes the following steps:

[0049] Step 1, Prepare the mold for cement-based retarded mortar test:

[0050] Plaster-based core mold test blocks were prepared by mixing gypsum powder and water at a water / solid ratio of 0.77 to 0.78. The gypsum core molds were dried and taken out for later use.

[0051] Apply machine oil evenly to the inner surface of the plastic mold and let it stand for later use.

[0052] After placing the plaster core mold inside the plastic test mold, fix the plaster core mold and the plastic test mold to make a cement-based retarded mortar test mold for later use.

[0053] Step 2, prepare cement-based retarded mortar test molds:

[0054] Each cubic meter of test mold body 1 contains the following components by mass: cement (PO 52.5) ​​596~605, fly ash 96~104, quartz sand 1196~1204, silica fume 296~304, water-reducing agent 30~40, copper-plated steel fiber 152~158.

[0055] After mixing, pour it into the cement-based retarded mortar test mold from step 1;

[0056] Step 3: After curing the cement-based retarded mortar test mold from Step 2, remove the plastic test mold to obtain the main body 1 of the test mold.

[0057] Step 4: After steam curing the embryo of the test mold body 1 from step 3, remove the plaster core mold inside the embryo of the test mold body 1 to make the test groove 11;

[0058] Step 5: Spray a composite aqueous solution of sodium silicate hydrate, magnesium fluorosilicate and potassium fluorosilicate onto the inner surface of the test groove 11 in step 4 for surface treatment. The spraying ratio is sodium silicate hydrate: magnesium fluorosilicate: potassium fluorosilicate: deionized water in the ratio of (2.9~3.1):(1.9~2.1):(0.9~1.1):(3.9~4.1) by mass to prepare a cement-based retarded mortar test mold.

[0059] The present invention uses a 70.7mm×70.7mm×70.7mm mold to conduct 10 sets of simulation tests. The average setting time is 1.5 days, which is less than the target requirement of 2 days, indicating that the test mold body 1 of the present invention can effectively reduce its setting time. Example 5:

[0060] The method for preparing cement-based retarded mortar test molds includes the following steps:

[0061] Step 1, Prepare the mold for cement-based retarded mortar test:

[0062] A gypsum-based core mold specimen with dimensions of 70.7mm × 70.7mm × 70.7mm was prepared. The gypsum powder and water were mixed at a water / solid ratio of 0.76. First, 760g of water was placed in a mixing pot, and 1000g of gypsum powder was added. The mixture was stirred for 60-70 seconds until a homogeneous slurry was formed. The slurry was then poured into a 70.7mm × 70.7mm × 70.7mm plastic mold, the surface was smoothed, and the mold was allowed to stand at room temperature (24±1℃) for 2-2.5 hours before being removed. The mold was then placed in a forced-air drying oven and dried at 40±1℃ for 5-5.5 hours before being taken out for use.

[0063] Apply machine oil evenly to the inner surface of the plastic mold and let it stand for later use.

[0064] After placing the plaster core mold at the center point inside the plastic test mold, cut four plastic tubes with a length of 39.7 to 39.9 mm to support it inside the plastic test mold, ensuring that the plaster core mold is located in the center of the plastic test mold. Fix the plaster core mold to the plastic test mold to make a cement-based retarded mortar test mold for later use.

[0065] Step 2, prepare cement-based retarded mortar test molds:

[0066] Each cubic meter of the test mold body 1 contains the following components by mass:

[0067] Cement (PO 52.5): 596~605, fly ash: 96~104, quartz sand: 1196~1204, silica fume: 296~304, water reducing agent: 30~40, copper-plated steel fiber: 152~158;

[0068] Add cement, fly ash, quartz sand, and silica fume to the mixer in sequence, dry mix for 6 to 6.5 minutes, then continue mixing for 5 to 5.5 minutes. Slowly add water and water-reducing agent, mix thoroughly, and then evenly sprinkle in copper-plated steel fibers. Continue mixing for 3 to 3.5 minutes, then pour into the cement-based retarded mortar test mold from step 1. Vibrate using a magnetic vibration table for 2 to 2.5 minutes, and then smooth the surface.

[0069] Step 3: Curing the cement-based retarded mortar test mold from Step 2 at a temperature of 20±2℃ and a humidity greater than 95% for 24 to 25 hours, then removing the plastic test mold to obtain the main body 1 of the test mold.

[0070] Step 4: After steaming and curing the test mold body 1 embryo from Step 3 at 80-85℃ for 48-49 hours, soak it in a saturated Ca(OH)2 aqueous solution for 24-25 hours, and then remove the plaster core mold inside the test mold body 1 embryo to make the test groove 11.

[0071] Step 5: Repair any unevenness on the inner surface of the cement-based retarded mortar mold to ensure the inner diameter error is 70.7±1mm. Fill the supporting plastic tube with a powder ratio of cement:silica fume:fly ash:mineral powder = 6:2:1:1, and a water / solid ratio of 0.6. After filling and allowing it to stand for one day, spray a composite aqueous solution of sodium silicate hydrate, magnesium fluorosilicate, and potassium fluorosilicate onto the inner surface of the test groove 11 from Step 4 for surface treatment. The spraying ratio, by mass, is sodium silicate hydrate:magnesium fluorosilicate:potassium fluorosilicate:deionized water = 3:2:1:4. The composite aqueous solution is left to stand for 20 days, during which time clean water is sprayed onto the inner surface of the mold every 7 days. After the inner surface treatment is completed, the mold preparation is finished.

[0072] In the laboratory molding test of the retarded mortar of this invention, the prepared retarded mortar is poured into a cement-based retarded mortar mold. The mold is then placed in a 20°C forced-air drying oven to simulate the air convection conditions after the retarded mortar is applied to the wall. After the retarded mortar has hardened inside the mold, the specimen is removed using an air gun through the air pores at the bottom of the mold for laboratory testing. Compared to traditional molds, the setting and hardening time can be accelerated by 6.5 days, significantly shortening the testing cycle of the retarded mortar, improving testing efficiency, and ensuring that laboratory test data matches on-site construction data. This allows manufacturers to adjust the mix proportions in a timely manner based on on-site construction to improve project quality. Example 6:

[0073] The method for preparing cement-based retarded mortar test molds includes the following steps:

[0074] Step 1, Prepare the mold for cement-based retarded mortar test:

[0075] A gypsum-based core mold specimen with dimensions of 70.7mm × 70.7mm × 70.7mm was prepared. Gypsum powder and water were mixed at a water / solid ratio of 0.765 to prepare the core mold specimen. First, 765g of water was placed in a mixing pot, and 1000g of gypsum powder was added. The mixture was stirred for 66 seconds until a homogeneous slurry was formed. The slurry was then poured into a 70.7mm × 70.7mm × 70.7mm plastic mold, the surface was smoothed, and the mold was allowed to stand at room temperature (25℃) for 2 hours before being removed. The mold was then placed in a forced-air drying oven and dried at 41℃ for 5 hours before being taken out for use.

[0076] Apply machine oil evenly to the inner surface of the plastic mold and let it stand for later use.

[0077] After placing the plaster core mold at the center point inside the plastic test mold, cut four plastic tubes with a length of 39.7 to 39.9 mm to support it inside the plastic test mold, ensuring that the plaster core mold is located in the center of the plastic test mold. Fix the plaster core mold to the plastic test mold to make a cement-based retarded mortar test mold for later use.

[0078] Step 2, prepare cement-based retarded mortar test molds:

[0079] Each cubic meter of the test mold body 1 contains the following components by mass:

[0080] Cement (PO 52.5): 598, fly ash: 98, quartz sand: 1198, silica fume: 298, water-reducing agent: 36, copper-plated steel fiber: 154;

[0081] Add cement, fly ash, quartz sand, and silica fume to the mixer in sequence, dry mix for 6 minutes, continue mixing for 5.5 minutes, slowly add water and water-reducing agent, mix thoroughly, evenly sprinkle in copper-plated steel fiber, continue mixing for 3 minutes, pour into the cement-based retarded mortar test mold from step 1, vibrate for 2 minutes using a magnetic vibration table, and scrape the surface smooth.

[0082] Step 3: Curing the cement-based retarded mortar test mold from Step 2 at a temperature of 20±2℃ and a humidity of more than 95% for 24 hours, then removing the plastic test mold to obtain the main body 1 of the test mold.

[0083] Step 4: After steaming and curing the test mold body 1 embryo from Step 3 at 80℃ for 49 hours, soak it in a saturated Ca(OH)2 aqueous solution for 25 hours, and then remove the plaster core mold inside the test mold body 1 embryo to make the test groove 11.

[0084] Step 5: Repair any unevenness on the inner surface of the cement-based retarded mortar mold to ensure the inner diameter error is 70.7±1mm. Fill the supporting plastic tube with a powder ratio of cement:silica fume:fly ash:mineral powder = 6:2:1:1, and a water / solid ratio of 0.6. After filling and allowing it to stand for one day, spray a composite aqueous solution of sodium silicate hydrate, magnesium fluorosilicate, and potassium fluorosilicate onto the inner surface of the test groove 11 from Step 4 for surface treatment. The spraying ratio, by mass, is sodium silicate hydrate:magnesium fluorosilicate:potassium fluorosilicate:deionized water = 3:2:1:4. The composite aqueous solution is left to stand for 20 days, during which time clean water is sprayed onto the inner surface of the mold every 7 days. After the inner surface treatment is completed, the mold preparation is finished.

[0085] In the laboratory molding test of the retarded mortar of this invention, the prepared retarded mortar is poured into a cement-based retarded mortar mold. The mold is then placed in a 20°C forced-air drying oven to simulate the air convection conditions after the retarded mortar is applied to the wall. After the retarded mortar has hardened inside the mold, the specimen is removed using an air gun through the air pores at the bottom of the mold for laboratory testing. Compared to traditional molds, the setting and hardening time can be accelerated by 6.5 days, significantly shortening the testing cycle of the retarded mortar, improving testing efficiency, and ensuring that laboratory test data matches on-site construction data. This allows manufacturers to adjust the mix proportions in a timely manner based on on-site construction to improve project quality. Example 7:

[0086] The method for preparing cement-based retarded mortar test molds includes the following steps:

[0087] Step 1, Prepare the mold for cement-based retarded mortar test:

[0088] A gypsum-based core mold specimen with dimensions of 70.7mm × 70.7mm × 70.7mm was prepared. The gypsum powder and water were mixed at a water / solid ratio of 0.77 to prepare the core mold specimen. First, 770g of water was placed in a mixing pot, and 1000g of gypsum powder was added. The mixture was stirred for 68 seconds until a homogeneous slurry was formed. The slurry was then poured into a 70.7mm × 70.7mm × 70.7mm plastic mold, the surface was smoothed, and the mold was allowed to stand at room temperature (23℃) for 2.4 hours before being removed. The mold was then placed in a forced-air drying oven and dried at 39℃ for 5.4 hours before being taken out for use.

[0089] Apply machine oil evenly to the inner surface of the plastic mold and let it stand for later use.

[0090] After placing the plaster core mold at the center point inside the plastic test mold, cut four plastic tubes with a length of 39.8mm to support it inside the plastic test mold, ensuring that the plaster core mold is located in the center of the plastic test mold. Fix the plaster core mold to the plastic test mold to make a cement-based retarded mortar test mold for later use.

[0091] Step 2, prepare cement-based retarded mortar test molds:

[0092] Each cubic meter of the test mold body 1 contains the following components by mass:

[0093] Cement (PO 52.5): 602, fly ash: 102, quartz sand: 1202, silica fume: 302, water-reducing agent: 38, copper-plated steel fiber: 156;

[0094] Add cement, fly ash, quartz sand, and silica fume to the mixer in sequence, dry mix for 6 to 6.5 minutes, then continue mixing for 5.5 minutes. Slowly add water and water-reducing agent, mix thoroughly, and then evenly sprinkle in copper-plated steel fibers. Continue mixing for 3.5 minutes, then pour into the cement-based retarded mortar test mold from step 1. Vibrate using a magnetic vibration table for 2.5 minutes, and then smooth the surface.

[0095] Step 3: Curing the cement-based retarded mortar test mold from Step 2 at a temperature of 20±2℃ and a humidity greater than 95% for 25 hours, then removing the plastic test mold to obtain the main body 1 of the test mold.

[0096] Step 4: After steaming and curing the test mold body 1 embryo from step 3 at 85°C for 48 hours, soak it in a saturated Ca(OH)2 aqueous solution for 24 hours, and then remove the plaster core mold inside the test mold body 1 embryo to make the test groove 11.

[0097] Step 5: Repair any unevenness on the inner surface of the cement-based retarded mortar mold to ensure the inner diameter error is 70.7±1mm. Fill the supporting plastic tube with a powder ratio of cement:silica fume:fly ash:mineral powder = 6:2:1:1, and a water / solid ratio of 0.6. After filling and allowing it to stand for one day, spray a composite aqueous solution of sodium silicate hydrate, magnesium fluorosilicate, and potassium fluorosilicate onto the inner surface of the test groove 11 from Step 4 for surface treatment. The spraying ratio, by mass, is sodium silicate hydrate:magnesium fluorosilicate:potassium fluorosilicate:deionized water = 3:2:1:4. The composite aqueous solution is left to stand for 20 days, during which time clean water is sprayed onto the inner surface of the mold every 7 days. After the inner surface treatment is completed, the mold preparation is finished. Example 8:

[0098] The method for preparing cement-based retarded mortar test molds includes the following steps:

[0099] Step 1, Prepare the mold for cement-based retarded mortar test:

[0100] A gypsum-based core mold specimen with dimensions of 70.7mm × 70.7mm × 70.7mm was prepared. Gypsum powder and water were mixed at a water / solid ratio of 0.76 to prepare the core mold specimen. First, 760g of water was placed in a mixing pot, and 1000g of gypsum powder was added. The mixture was stirred for 60 seconds until a homogeneous slurry was formed. The slurry was then poured into a 70.7mm × 70.7mm × 70.7mm plastic mold, the surface was smoothed, and the mold was allowed to stand at room temperature (24±1℃) for 2 hours before being removed. The mold was then placed in a forced-air drying oven and dried at 40℃ for 5 hours before being taken out for use.

[0101] Apply machine oil evenly to the inner surface of the plastic mold and let it stand for later use.

[0102] After placing the plaster core mold at the center point inside the plastic test mold, cut four plastic tubes with a length of 39.7mm to support it inside the plastic test mold, ensuring that the plaster core mold is located in the center of the plastic test mold. Fix the plaster core mold to the plastic test mold to make a cement-based retarded mortar test mold for later use.

[0103] Step 2, prepare cement-based retarded mortar test molds:

[0104] Each cubic meter of the test mold body 1 contains the following components by mass:

[0105] Cement (PO 52.5): 600, fly ash: 100, quartz sand: 1200, silica fume: 300, water-reducing agent: 35, copper-plated steel fiber: 156;

[0106] Add cement, fly ash, quartz sand, and silica fume into the mixer in sequence, dry mix for 6 minutes, continue mixing for 5 minutes, slowly add water and water-reducing agent, mix thoroughly, evenly sprinkle in copper-plated steel fiber, continue mixing for 3 minutes, pour into the cement-based retarded mortar test mold from step 1, vibrate for 2 minutes using a magnetic vibration table, and scrape the surface smooth.

[0107] Step 3: Curing the cement-based retarded mortar test mold from Step 2 at 20°C and humidity greater than 95% for 24 hours, then removing the plastic test mold to obtain the main body 1 of the test mold.

[0108] Step 4: After steaming and curing the test mold body 1 preform from Step 3 at 80℃ for 48 hours, soak it in a saturated Ca(OH)2 aqueous solution for 24 hours, and then remove the plaster core mold inside the test mold body 1 preform to make the test groove 11.

[0109] Step 5: Repair any unevenness on the inner surface of the cement-based retarded mortar mold to ensure the inner diameter error is 70.7±1mm. Fill the supporting plastic tube with a powder ratio of cement:silica fume:fly ash:mineral powder = 6:2:1:1, and a water / solid ratio of 0.6. After filling and allowing it to stand for one day, spray a composite aqueous solution of sodium silicate hydrate, magnesium fluorosilicate, and potassium fluorosilicate onto the inner surface of the test groove 11 from Step 4 for surface treatment. The spraying ratio, by mass, is sodium silicate hydrate:magnesium fluorosilicate:potassium fluorosilicate:deionized water = 3:2:1:4. The composite aqueous solution is left to stand for 20 days, during which time clean water is sprayed onto the inner surface of the mold every 7 days. After the inner surface treatment is completed, the mold preparation is finished.

[0110] Tests showed that the 3-day compressive strength of mold body 1 reached 157.5 MPa, demonstrating high compressive strength. Simultaneously, the slump expansion was 675 mm, and the T500 flow time was 6 seconds, indicating good slurry fluidity, which effectively reduces molding difficulty and improves mold quality.

Claims

1. A cement-based retarded mortar test mold, comprising the main body of the test mold (1), characterized in that, The main body of the test mold (1) is a cement-based test mold with a compressive strength of 155-170 MPa. It has a test groove (11) inside. The inner surface of the test groove (11) is sprayed with a composite aqueous solution of sodium silicate hydrate, magnesium fluorosilicate and potassium fluorosilicate for surface treatment. The spraying ratio is sodium silicate hydrate: magnesium fluorosilicate: potassium fluorosilicate: deionized water in the ratio of (2.9-3.1): (1.9-2.1): (0.9-1.1): (3.9-4.1).

2. The cement-based retarding mortar test mold according to claim 1, characterized in that, The main body of the test mold (1) is a cubic structure of 150mm×150mm×150mm, and its interior is provided with a cubic test groove (11) of 70.7mm×70.7mm×70.7mm.

3. The cement-based retarding mortar test mold according to claim 1, characterized in that each The 1 cubic meter test mold body (1) contains the following components by mass: PO 52.5 cement: 596~605, fly ash: 96~104, quartz sand: 1196~1204, silica fume: 296~304, water-reducing agent: 30~40, copper-plated steel fiber: 152~158.

4. The cement-based retarding mortar test mold according to claim 3, characterized in that, Each cubic meter of the test mold body (1) contains the following components by mass: PO 52.5 cement: 600, fly ash: 100, quartz sand: 1200, silica fume: 300, water-reducing agent: 35-40, copper-plated steel fiber:

156.

5. A method for preparing cement-based retarded mortar test molds, characterized in that, Includes the following steps: Step 1, Prepare the mold for cement-based retarded mortar test: Plaster-based core mold test blocks were prepared by mixing gypsum powder and water at a water / solid ratio of 0.76 to 0.

78. The gypsum core molds were dried and taken out for later use. Apply machine oil evenly to the inner surface of the plastic mold and let it stand for later use. After placing the plaster core mold inside the plastic test mold, fix the plaster core mold and the plastic test mold to make a cement-based retarded mortar test mold for later use. Step 2, prepare cement-based retarded mortar test molds: Each cubic meter of the test mold body (1) contains the following components by mass: PO 52.5 cement: 596~605, fly ash: 96~104, quartz sand: 1196~1204, silica fume: 296~304, water-reducing agent: 30~40, copper-plated steel fiber: 152~158; After mixing, pour it into the cement-based retarded mortar test mold from step 1; Step 3: After curing the cement-based retarded mortar test mold from Step 2, remove the plastic test mold to obtain the main body (1) of the test mold. Step 4: After steam curing the embryo of the test mold body (1) from step 3, take out the plaster core mold inside the embryo of the test mold body (1) to make the test groove (11). Step 5: Spray a composite aqueous solution of sodium silicate hydrate, magnesium fluorosilicate and potassium fluorosilicate onto the inner surface of the test groove (11) in step 4 for surface treatment. The spraying ratio is 3:2:1:4 by mass of sodium silicate hydrate: magnesium fluorosilicate: potassium fluorosilicate: deionized water, and a cement-based slow-setting mortar test mold is made.

6. The method for preparing cement-based retarded mortar test molds according to claim 5, characterized in that, In step 1, a gypsum-based core mold test block with dimensions of 70.7mm × 70.7mm × 70.7mm is prepared. First, 760g of water is placed in a mixing pot, and 1000g of gypsum powder is added. The mixture is stirred for 60s to 70s until a uniform slurry is formed. Then, the slurry is poured into a 70.7mm × 70.7mm × 70.7mm plastic mold, the surface is smoothed, and the mold is left to stand at room temperature (24±1℃) for 2 to 2.5 hours before being removed. The mold is then placed in a forced-air drying oven and dried at 40±1℃ for 5 to 5.5 hours before being taken out for use. After placing the plaster core mold inside the plastic test mold, cut four plastic tubes with a length of 39.7 to 39.9 mm to support it inside the plastic test mold, ensuring that the plaster core mold is located in the center of the plastic test mold.

7. The method for preparing cement-based retarded mortar test molds according to claim 5, characterized in that, In step 2, cement, fly ash, quartz sand, and silica fume are added to the mixer in sequence and dry-mixed for 6 to 6.5 minutes. Then, mixing is continued for 5 to 5.5 minutes. Water and water-reducing agent are added and mixed thoroughly. Copper-plated steel fibers are then evenly sprinkled in and mixing is continued for 3 to 3.5 minutes. The mixture is then poured into the cement-based retarded mortar test mold from step 1 and vibrated for 2 to 2.5 minutes using a magnetic vibration table. The surface is then smoothed.

8. The method for preparing cement-based retarded mortar test molds according to claim 5, characterized in that, In step 3, the cement-based slow-setting mortar test mold from step 2 is cured at a temperature of 20±2℃ and a humidity of more than 95% for 24 to 25 hours. The plastic test mold is then removed to obtain the main body of the test mold (1) embryo.

9. The method for preparing cement-based retarded mortar test molds according to claim 5, characterized in that, In step 4, the test mold body (1) embryo from step 3 is steamed at 80-85°C for 48-49 hours, then soaked in saturated Ca(OH)2 aqueous solution for 24-25 hours, and then the plaster core mold inside the test mold body (1) embryo is taken out to make the test groove (11).

10. The method for preparing cement-based retarded mortar test molds according to claim 6, characterized in that, In step 5, the unevenness on the inner surface of the cement-based retarded mortar mold is repaired so that the inner diameter error of the cement-based retarded mortar mold is 70.7±1mm; the plastic tube for support is filled, and the powder ratio of the filling material is cement: silica fume: fly ash: mineral powder = 6:2:1:1, and the water / solid ratio of the powder is 0.6.

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