CN112919862A - Large-volume concrete and preparation method thereof - Google Patents

Abstract

The application relates to the field of concrete preparation technology, and particularly discloses mass concrete and a preparation method thereof. The bulk concrete comprises the following components: cement, medium sand, broken stone, ultrafine fly ash, pumping agent, gel reducing agent, expanding agent, sodium acetate, polyamide fiber and water; the preparation method comprises the following steps: s1: mixing cement, medium sand, broken stone, ultrafine fly ash and water, and stirring for 30-60s to obtain uniformly stirred premixed concrete; s2: and mixing the pumping aid, the gel reducing agent, the expanding agent, the sodium acetate, the polyamide fiber and the ready-mixed concrete, and stirring for 60-120s to obtain the mass concrete. The application of bulky concrete has and reduces cement quantity advantage when guaranteeing the concrete strength.

Description

Large-volume concrete and preparation method thereof

Technical Field

The application relates to the field of concrete preparation technology, in particular to mass concrete and a preparation method thereof.

Background

The modern buildings often involve mass concrete construction, such as high-rise building foundations, large equipment foundations, water conservancy dams and the like. The method is specified in Chinese 'Mass concrete construction Standard' GB 50496-2018: mass concrete with concrete structure body minimum geometric dimension not less than 1m, or concrete which is expected to cause harmful crack generation due to temperature change and shrinkage caused by hydration of cementing material in concrete, is called large volume concrete.

Related art as application document with application number 200910025167.2, a C50 mass concrete is disclosed, which comprises the following raw materials in parts by weight: 300 parts of cement, 1100 parts of crushed stone, 620 parts of sand, 180 parts of water, 200 parts of ground slag and 7 parts of admixture SPA. The prepared concrete has better anti-cracking performance.

In view of the above-mentioned related technologies, the inventor believes that the cement consumption of the mass concrete in the related technologies is large, and generally about 20% to 30% of the cement in the concrete does not participate in the hydration reaction, and only plays a filling role, and the cement strength cannot be effectively exerted, thereby causing a large cost waste.

Disclosure of Invention

In order to reduce the using amount of cement and ensure the strength of concrete, the application provides mass concrete and a preparation method thereof.

In a first aspect, the present application provides a mass concrete, which adopts the following technical scheme:

the bulk concrete is prepared from the following raw materials in parts by weight: 300-340 parts of cement, 720-740 parts of medium sand, 1070 parts of crushed stone 1040-1070 parts, 130 parts of ultrafine fly ash, 7-9 parts of pumping agent, 2-4 parts of glue reducing agent, 20-25 parts of expanding agent and 160 parts of water 140-160;

the gel reducing agent comprises the following components in percentage by weight: 7-12% of triethanolamine, 8-14% of tartaric acid, 13-17% of alkyl sodium sulfonate, 9-18% of sodium sulfate and 43-54% of water.

By adopting the technical scheme, the mass concrete prepared by mixing the raw materials has good service performance, and the cement particles can be dispersed by adding a proper amount of the gel reducing agent and the ultrafine fly ash, so that the hydration degree of the cement is improved, and the strength of the prepared concrete still meets the strength requirement of the C50 concrete while the cement dosage is reduced.

The sodium alkyl sulfonate is an anionic surfactant, a strong hydrophilic sulfonic group is connected with a hydrocarbon group in a molecular structure, and the sodium alkyl sulfonate has strong surface activity, is beneficial to promoting the dispersion of cement particles, increasing the contact area of the cement particles and water, and improving the hydration degree of cement, thereby effectively exerting the strength enhancing performance of the cement.

The sodium sulfate can react with hydration products of cement to generate hydrated calcium sulfate and hydrated calcium sulphoaluminate, and the hydrated calcium sulfate and the hydrated calcium sulphoaluminate have higher strength after hardening, so that the compressive strength of the concrete can be further improved.

Because cement hydration produces the heat, the inside heat dissipation of bulky concrete is slow and the surface heat dissipation is fast to cause inside and outside difference in temperature too big, the glue reducing agent of this application reduces the cement quantity, thereby reduces the heat of hydration of cement, and the bulky concrete that makes is difficult to the fracture, has better working property.

The components are combined, so that the prepared mass concrete can reduce the using amount of cement, ensure that the compressive strength of the concrete meets the requirement and has better working performance.

Preferably, the fineness of the ultrafine fly ash is 0.2-0.4.

By adopting the technical scheme, the fineness of the ultrafine fly ash is selected within the range, the particle size of the ultrafine fly ash is slightly smaller than that of the cement particles, and the ultrafine fly ash can be filled in gaps among the cement particles, so that the action area of the ultrafine fly ash and the cement is increased, and the porosity of the cement is reduced. And the ultrafine fly ash with smaller fineness has stronger activity, so that the internal crystal structure of the ultrafine fly ash is weakened, the progress of the hydration reaction of the fly ash is promoted, more hydrate is generated in the middle and later stages, and the strength of the cement is improved.

Preferably, the expanding agent consists of the following components in percentage by weight: 32 to 44 percent of calcium oxide and 56 to 68 percent of aluminum calcium sulfate.

By adopting the technical scheme, the expanding agent of the components is added into the concrete, a large amount of expansive crystalline hydrate is generated after being mixed with water, the concrete is enabled to generate proper expansion, the generated expansion can be converted into compressive stress under the constraint of the steel bars and the templates, and the compressive stress offsets the shrinkage and tensile stress of the concrete in the hardening process, so that the problem of cracks generated by cement hardening is reduced.

Preferably, the pumping agent is a polycarboxylic acid pumping agent.

By adopting the technical scheme, the polycarboxylic acid pumping agent can reduce the using amount of cement under the condition of not changing the proportion of various raw materials, and meanwhile, the polycarboxylic acid pumping agent has the steric hindrance effect, plays a role in dispersing and maintaining the dispersion of cement particles, can play a better role in space filling or mediation, and thus effectively improves the strength of concrete.

Preferably, the raw material also comprises 12 to 16 parts by weight of sodium acetate.

By adopting the technical scheme, sodium acetate is added into the concrete to be neutralized with alkali substances in the cement, so that the setting and hardening of the cement are delayed, the hydration reaction time of the cement is prolonged, the hydration reaction of the cement is more sufficient, and the improvement of the strength of the concrete is facilitated.

Preferably, the particle size of the sodium acetate is 3-5 mm.

By adopting the technical scheme, the particle size of the sodium acetate is selected within the range, and the sodium acetate particles can be better diffused among cement particles in the stirring process, so that the neutralization reaction of the sodium acetate and alkali substances is promoted, and the hydration reaction time of the cement is prolonged.

Preferably, the raw materials also comprise 5-10 parts of polyamide fiber.

By adopting the technical scheme, the polyamide has higher strength, the polyamide fiber can be uniformly dispersed in concrete slurry in the concrete mixing process, the binding power of a cementing material and other aggregates can be effectively improved, the problem of shrinkage cracking of the concrete in the hardening process is reduced, and the strength of the hardened concrete is improved.

In a second aspect, the present application provides a method for preparing a mass concrete, which adopts the following technical scheme:

a preparation method of mass concrete comprises the following preparation steps:

s1: mixing cement, medium sand, broken stone, ultrafine fly ash and water, and stirring for 30-60s to obtain uniformly stirred premixed concrete;

s2: and mixing the pumping aid, the gel reducing agent, the expanding agent and the ready-mixed concrete, and stirring for 60-120s to obtain the mass concrete.

By adopting the technical scheme, the cement, the medium sand, the broken stone, the ultrafine fly ash and the water are mixed and stirred to prepare the premixed concrete, then the pumping aid, the gel reducing agent, the expanding agent and the premixed concrete are mixed and stirred to the specified time, so that the preparation of the mass concrete is completed, the consumption of the prepared concrete cement is reduced, the strength can meet the requirement, and the working performance is stable.

Preferably, 12 to 16 parts of sodium acetate and/or 5 to 10 parts of polyamide fiber are also added in the step S2.

By adopting the technical scheme, the strength of the concrete can be effectively improved by adding the sodium acetate and/or the polyamide fiber into the premixed concrete, the operation process is simple, and the working efficiency is high.

In summary, the present application has the following beneficial effects:

1. because the glue reducing agent is adopted to improve the dispersion degree of cement, the glue reducing agent comprises sodium alkylsulfonate and sodium sulfate, the sodium alkylsulfonate has stronger surface activity, thereby being beneficial to promoting the dispersion of cement particles and improving the hydration degree of the cement, and the sodium sulfate can react with a cement hydration product to generate hydrated calcium sulfate and hydrated calcium sulfoaluminate with higher strength, thereby obtaining the effect of reducing the cement consumption and simultaneously keeping the concrete with better strength.

2. The application preferably adopts the ultrafine fly ash, because the particle size of ultrafine fly ash slightly is less than the particle size of cement granule, can pack in the interstitial space of cement granule, increases the area of action of ultrafine fly ash and cement, and the ultrafine fly ash has stronger activity simultaneously, can generate more hydrate, has obtained improvement concrete strength effect.

3. According to the method, the premixed concrete is prepared by mixing and stirring the cement, the medium sand, the gravel, the ultrafine fly ash and the water, then the sodium acetate, the polyamide fiber, the pumping agent, the glue reducing agent, the expanding agent and the premixed concrete are mixed, and the premixed concrete is stirred for the specified time, so that the preparation of the mass concrete is completed.

Detailed Description

The present application will be described in further detail with reference to examples.

The specifications of the materials used in the preparation examples, examples and comparative examples are as follows:

the cement is Portland cement with the label of P.O42.5;

the medium sand is purchased from a black river sand mining factory, the apparent density of the medium sand is 2560kg/m3, the mud content is 0.8 percent, and the fineness modulus is 2.7;

the crushed stone is purchased from a Jingyang quarry, the grading requirement of the crushed stone is 5-25mm continuous concentration, the apparent density of the crushed stone is 2620kg/m3, the mud content is 0.2%, and the crushing index is 6%;

the ultrafine fly ash is purchased from Shaanxi genuine fly ash comprehensive utilization company, and the common fly ash is purchased from Shaanxi genuine fly ash comprehensive utilization company;

the polycarboxylic acid pumping agent is purchased from Shaanxi Bohai sea chemical industry Co., Ltd, and has the water reduction rate of 25% and the gas content of 3.5%;

SY-G type bulking agents are available from south Beijing Taioho science and technology, Inc.;

naphthalene based pumping agents are available from jonan xin senegand ltd;

triethanolamine was purchased from Shandong Xin Chemicals, Inc.;

tartaric acid was purchased from Shandong Fengtai Biotech, Inc.;

sodium alkyl sulfonate was purchased from chemical ltd of Jintai, Jinan;

sodium sulfate was purchased from Guangliu chemical Co., Ltd, Sichuan;

calcium oxide was purchased from Zhengzhou Peniu environmental protection technology, Inc.;

aluminum calcium sulfate was purchased from corridor reclaimed water chemical limited;

sodium acetate was purchased from tsuzhou chemical ltd;

polyamide fibers were purchased from Yoppda technologies, Sichuan.

Preparation example of gel reducing agent

Preparation example 1

The gel reducing agent is prepared by mixing and stirring the following raw materials in parts by weight:

1.4kg of triethanolamine, 1.6kg of tartaric acid, 3.4kg of alkyl sodium sulfonate, 2.8kg of sodium sulfate and 10.8kg of water.

Preparation example 2

The gel reducing agent is prepared by mixing and stirring the following raw materials in parts by weight:

2.0kg of triethanolamine, 2.2kg of tartaric acid, 3.0kg of alkyl sodium sulfonate, 1.8kg of sodium sulfate and 11.0kg of water.

Preparation example 3

The gel reducing agent is prepared by mixing and stirring the following raw materials in parts by weight:

2.4kg of triethanolamine, 2.8kg of tartaric acid, 2.6kg of alkyl sodium sulfonate, 3.6kg of sodium sulfate and 8.6kg of water.

Examples

Example 1

The mass concrete is prepared from the following raw materials in parts by weight:

300kg of cement, 720kg of medium sand, 1040kg of broken stone, 110kg of ultrafine fly ash, 7kg of pumping aid, 2kg of gel reducing agent of preparation example 1, 20kg of expanding agent and 140kg of water.

The fineness of the ultrafine fly ash is 0.5, the pumping agent is a naphthalene pumping agent, and the expanding agent is a SY-G type expanding agent.

The mass concrete is prepared by the following steps:

s1: mixing cement, medium sand, broken stone, ultrafine fly ash and water, and stirring for 30s to obtain uniformly stirred premixed concrete;

s2: and mixing the pumping aid, the gel reducing agent, the expanding agent and the ready-mixed concrete, and stirring for 120s to obtain the mass concrete.

Example 2

320kg of cement, 730kg of medium sand, 740kg of crushed stone, 120kg of ultrafine fly ash, 8kg of pumping aid, 3kg of gel reducing agent of preparation example 1, 23kg of expanding agent and 150kg of water.

The fineness of the ultrafine fly ash is 0.5, the pumping agent is a naphthalene pumping agent, and the expanding agent is a SY-G type expanding agent.

The mass concrete is prepared by the following steps:

s1: mixing cement, medium sand, broken stone, ultrafine fly ash and water, and stirring for 45s to obtain uniformly stirred premixed concrete;

s2: and mixing the pumping aid, the gel reducing agent, the expanding agent and the ready-mixed concrete, and stirring for 90 seconds to obtain the mass concrete.

Example 3

340kg of cement, 740kg of medium sand, 1070kg of broken stone, 130kg of ultrafine fly ash, 9kg of pumping aid, 4kg of gel reducing agent of preparation example 1, 25kg of expanding agent and 160kg of water.

The fineness of the ultrafine fly ash is 0.5, the pumping agent is a naphthalene pumping agent, and the expanding agent is a SY-G type expanding agent.

The mass concrete is prepared by the following steps:

s1: mixing cement, medium sand, broken stone, ultrafine fly ash and water, and stirring for 60s to obtain uniformly stirred premixed concrete;

s2: and mixing the pumping aid, the gel reducing agent, the expanding agent and the ready-mixed concrete, and stirring for 60 seconds to obtain the large-volume concrete.

Example 4

A bulk concrete, differing from example 3 in that: the degelling agent of preparation 2 was selected for this example.

Example 5

A bulk concrete, differing from example 3 in that: the degelling agent of preparation 3 was selected for this example.

Example 6

A bulk concrete, differing from example 5 in that: in the embodiment, the selected ultrafine fly ash with the fineness of 0.4 is used.

Example 7

A bulk concrete, differing from example 5 in that: in the embodiment, the selected ultrafine fly ash with the fineness of 0.3 is used.

Example 8

A bulk concrete, differing from example 5 in that: in the embodiment, the selected ultrafine fly ash with the fineness of 0.2.

Example 9

A bulk concrete, differing from example 7 in that: the pumping agent of the embodiment is a polycarboxylic acid pumping agent.

Example 10

A bulk concrete, which differs from example 9 in that: in the expanding agent of this example, calcium oxide was 32% and calcium aluminum sulfate was 68%.

Example 11

A bulk concrete, which differs from example 9 in that: the expanding agent of this example contains 38% calcium oxide and 62% calcium aluminosulfate.

Example 12

A bulk concrete, which differs from example 9 in that: the expanding agent of this example contains 44% calcium oxide and 56% calcium aluminum sulfate.

Example 13

A bulk concrete, which differs from example 12 in that: in this example, 12kg of sodium acetate having a particle size of 3mm was added.

Example 14

A bulk concrete, which differs from example 12 in that: in this example, 14kg of sodium acetate having a particle size of 3mm was added.

Example 15

A bulk concrete, which differs from example 12 in that: in this example, 16kg of sodium acetate having a particle size of 3mm was added.

Example 16

A bulk concrete, which differs from example 15 in that: the particle size of the sodium acetate added in this example was 4 mm.

Example 17

A bulk concrete, which differs from example 15 in that: the particle size of sodium acetate added in this example was 5 mm.

Example 18

A bulk concrete, which differs from example 15 in that: 5kg of polyamide fiber was added to the raw material of this example.

Example 19

A bulk concrete, which differs from example 15 in that: 7kg of polyamide fibers were added to the raw materials of this example.

Example 20

A bulk concrete, which differs from example 15 in that: 10kg of polyamide fiber was added to the raw material of this example.

Example 21

A large-volume concrete, which is different from example 20 in that: in this example, sodium acetate was not added

Comparative example

Comparative example 1

The C50 bulk concrete is prepared from the following raw materials in parts by weight:

300kg of cement, 1100kg of broken stone, 620kg of sand, 180kg of water, 200kg of ground slag and 7kg of admixture.

The C50 mass concrete is prepared by the following steps:

s1: mixing cement, broken stone, sand, ground slag, an additive and water, and stirring for 120s to obtain the uniformly stirred concrete.

Comparative example 2

The concrete is prepared from the following raw materials in parts by weight:

350kg of cement, 670kg of medium sand, 1040kg of broken stone, 7kg of pumping aid, 20kg of expanding agent and 140kg of water; the pumping agent is a naphthalene pumping agent, and the swelling agent is a SY-G type swelling agent.

The concrete is prepared by the following steps:

s1: mixing cement, medium sand, broken stone and water, and stirring for 30 seconds to obtain uniformly stirred premixed concrete;

s2: and mixing the pumping aid and the expanding agent with the ready-mixed concrete, and stirring for 120s to obtain the concrete.

Comparative example 3

Comparative example 1 differs from example 1 in that: no size reducing agent was added.

Comparative example 4

Comparative example 3 differs from example 1 in that: no superfine fly ash is added.

Comparative example 5

Comparative example 4 differs from example 1 in that: in the comparative example, ordinary fly ash was used instead of the ultra-fine fly ash in example 1.

Performance test

Test for compressive Strength

Test samples: concrete mixtures obtained in examples 1 to 21 were used as test samples 1 to 21, and concrete mixtures obtained in comparative examples 1 to 5 were used as control samples 1 to 5.

The test method comprises the following steps: the concrete mixtures of the test samples 1-21 are prepared into concrete test blocks, the concrete mixtures of the reference samples 1-5 are prepared into concrete test blocks, and the 60d compressive strength (MPa) of the concrete is detected according to the compressive strength test in GB/T50081-2002 Standard test method for mechanical properties of common concrete.

The test instrument: pressure testing machine

And (3) test results: the test results of the test samples 1 to 21 are shown in Table 1, and the test results of the control samples 1 to 5 are shown in Table 2.

TABLE 1 test sample 1-21 compression Strength test results

As can be seen from table 1, when comparing the test samples 1 to 3, the strength grade of the mass concrete prepared in examples 1 to 3 of the present application meets the strength requirement of the C50 concrete, and the amount of cement added to the test sample 3 is higher, so that the test sample 3 has higher strength than the test samples 1 and 2.

As can be seen from Table 1, when the test samples 3-5 are compared, the strength grades of the mass concrete prepared by adding the glue reducing agents prepared in the preparation examples 1-3 of the application into the concrete meet the strength requirement of the C50 concrete.

As can be seen from table 1, when comparing the test samples 6 to 8 with the test sample 5, the fineness of the added ultrafine fly ash has a certain influence on the strength of the concrete when preparing the large-volume concrete, and when the fineness of the added ultrafine fly ash is 0.3, the ultrafine fly ash has stronger activity, which is more beneficial to the hydration reaction of the fly ash, so that the prepared concrete has higher strength.

As can be seen from table 1, when comparing the test sample 9 with the test samples 6 to 8, the polycarboxylic acid pumping agent is added when preparing the large-volume concrete, and the polycarboxylic acid pumping agent plays a role in dispersing and maintaining the dispersion of cement particles, thereby facilitating the maximum hydration reaction of cement, and improving the strength of the concrete, so that the polycarboxylic acid pumping agent has a better performance enhancing effect when being added when preparing the large-volume concrete than when being added with the naphthalene pumping agent.

As can be seen from Table 1, comparing test samples 10 to 12 with test sample 9, the present application provides a better strength-enhancing effect of the expansive agent on concrete than the purchased SY-G type expansive agent.

As can be seen from table 1, comparing the test samples 13 to 15 with the test sample 12, sodium acetate was added when preparing mass concrete, and the sodium acetate reacted with the alkaline substance in the cement, thereby prolonging the hydration time of the cement, allowing the cement hydration reaction to proceed more sufficiently, and improving the strength of the concrete; in the range of 12-16kg, the more sodium acetate is added, the better the concrete strength is.

As can be seen from Table 1, comparing the test samples 15 to 17, when the grain size of sodium acetate is within the range of 3 to 5mm, the sodium acetate with smaller grain size can be more uniformly diffused among cement grains during the concrete mixing process, which is beneficial to improving the hydration degree of cement, so that the test sample 15 has higher compressive strength.

As can be seen from Table 1, when comparing the test samples 18-20 with the test sample 15, the strength of the concrete can be effectively improved by adding the polyamide fiber when preparing the large-volume concrete, the polyamide fiber has a certain strength, and the polyamide fiber is uniformly dispersed in the concrete slurry in the concrete mixing process, so that the binding power between the cementing material and the aggregate can be effectively improved, and the strength of the concrete can be improved.

As can be seen from table 1, comparing the test samples 21, 20 and 15, the strength of the concrete can be enhanced by adding the polyamide fiber alone when preparing the mass concrete; the strength enhancement effect of the concrete is slightly worse when the polyamide fiber is added alone than when the sodium acetate is added alone; when the sodium acetate and the polyamide fiber are added simultaneously when preparing mass concrete, higher concrete strength can be obtained.

TABLE 2 comparative samples 1-5 compression Strength test results

As can be seen from tables 1 and 2, when the control sample 1 and the test sample 1 are compared, and cement with the same weight is added during the preparation of the large-volume concrete, the strength of the control sample 1 is much lower than that of the test sample 1, which shows that the compression strength of the large-volume concrete can be effectively improved by the ultrafine fly ash and the gel reducing agent.

It can be seen from tables 1 and 2 that, when comparing the comparison sample 2 with the test sample 1, the comparison sample 2 is added with 50kg of cement, the added weight is offset by the amount of the reduced middlings, the comparison sample 2 is not added with the ultrafine fly ash and the glue reducing agent, and the compression strength of the test sample 1 and the comparison sample 2 is not greatly different, which indicates that when the ultrafine fly ash and the glue reducing agent are added into the large-volume concrete, the amount of the cement can be effectively reduced on the premise of ensuring the concrete strength.

As can be seen from tables 1 and 2, when comparing the control samples 3 and 4 with the test sample 1, the strength enhancement effect of the concrete is reduced by adding the size reducing agent or the ultrafine fly ash alone when preparing the large-volume concrete compared with adding the size reducing agent and the fly ash simultaneously.

As can be seen from tables 1 and 2, when comparing the comparison sample 5 with the test sample 1, the ultrafine fly ash added during the preparation of the large-volume concrete has stronger activity and is beneficial to promoting the hydration reaction of the fly ash compared with the addition of the common fly ash, so that the test sample 1 has higher compressive strength than the comparison sample 5.

The present embodiment is only for explaining the present application, and it is not limited to the present application, and those skilled in the art can make modifications of the present embodiment without inventive contribution as needed after reading the present specification, but all of them are protected by patent law within the scope of the claims of the present application.

Claims (9)

1. The mass concrete is characterized by being prepared from the following raw materials in parts by weight: 300-340 parts of cement, 720-740 parts of medium sand, 1070 parts of crushed stone 1040-1070 parts, 130 parts of ultrafine fly ash, 7-9 parts of pumping agent, 2-4 parts of glue reducing agent, 20-25 parts of expanding agent and 160 parts of water 140-160;

the gel reducing agent comprises the following components in percentage by weight: 7-12% of triethanolamine, 8-14% of tartaric acid, 13-17% of alkyl sodium sulfonate, 9-18% of sodium sulfate and 43-54% of water.

2. A bulk concrete according to claim 1, wherein: the fineness of the ultrafine fly ash is 0.2-0.4.

3. A bulk concrete according to claim 1, wherein: the expanding agent comprises the following components in percentage by weight: 32 to 44 percent of calcium oxide and 56 to 68 percent of aluminum calcium sulfate.

4. A bulk concrete according to claim 1, wherein: the pumping agent is selected from polycarboxylic acid pumping agents.

5. A bulk concrete according to claim 1, wherein: the raw material also comprises 12-16 parts of sodium acetate by weight.

6. A mass concrete according to claim 5, wherein: the grain size of the sodium acetate is 3-5 mm.

7. A mass concrete according to claim 1 or 6, wherein: the raw materials also comprise 5-10 parts of polyamide fiber.

8. A method for preparing a mass concrete according to any one of claims 1 to 4, characterized in that: comprises the following preparation steps:

s1: mixing cement, medium sand, broken stone, ultrafine fly ash and water, and stirring for 30-60s to obtain uniformly stirred premixed concrete;

s2: and mixing the pumping aid, the gel reducing agent, the expanding agent and the ready-mixed concrete, and stirring for 60-120s to obtain the mass concrete.

9. The method for preparing mass concrete according to claim 8, wherein: 12-16 parts of sodium acetate and/or 5-10 parts of polyamide fiber are also added in the step S2.