CN113213872B

CN113213872B - Super-retarding concrete and preparation method thereof

Info

Publication number: CN113213872B
Application number: CN202110567861.8A
Authority: CN
Inventors: 郑正顺; 詹强; 向祚铁; 金科益
Original assignee: Hangzhou Sanzhong New Building Materials Technology Co ltd
Current assignee: Hangzhou Sanzhong New Building Materials Technology Co ltd
Priority date: 2021-05-24
Filing date: 2021-05-24
Publication date: 2022-10-11
Anticipated expiration: 2041-05-24
Also published as: CN113213872A

Abstract

The application relates to the technical field of concrete, and particularly discloses super-retarding concrete and a preparation method thereof, wherein the concrete comprises the following raw materials in parts by weight: 300-350 parts of cement, 70-80 parts of mineral powder, 45-55 parts of fly ash, 950-1050 parts of coarse aggregate, 700-800 parts of fine aggregate, 1.5-4 parts of retarder, 2-5 parts of reinforcing agent, 1-3 parts of gypsum, 0.8-1.2 parts of vegetable oil, 1-3 parts of water reducer and 150-200 parts of water; the retarder consists of soybean protein and sodium pyrophosphate, and the weight ratio of the soybean protein to the sodium pyrophosphate is 1 (1-2); the preparation method of the concrete comprises the following steps: mixing 30-50 parts by weight of water, coarse aggregate, fine aggregate, fly ash and mineral powder, adding cement, the balance of water and a water reducing agent after uniformly mixing, and obtaining a first mixture after uniformly mixing; mixing the first mixture with a retarder, a reinforcing agent, gypsum and vegetable oil, and uniformly mixing to obtain super-retarding concrete; the concrete of this application has the effectual advantage of slow setting.

Description

Super-retarding concrete and preparation method thereof

Technical Field

The application relates to the technical field of concrete, in particular to super-retarding concrete and a preparation method thereof.

Background

The concrete is artificial stone which is formed by taking cement as a main gel material, mixing with water, sand, stones, mineral admixture and some chemical admixture according to a proper proportion, uniformly stirring, compacting, molding, curing and hardening.

The demand of concrete in engineering construction is getting larger and larger, and people have certain requirements on the setting time of the concrete; when the setting time is too short, the concrete is easy to set quickly, and is not beneficial to construction and transportation; in recent years, people add retarders into concrete to achieve the effect of prolonging the setting time of the concrete, thereby improving the quality of the concrete; the prior retarder molasses retarder is relatively common.

Through the related technologies, the mixing amount of the prior molasses retarder is difficult to control, the mixing amount is too small, the retarding effect is poor, the mixing amount is large, the coagulation accelerating effect is easy to occur, and the retarding effect is poor.

Disclosure of Invention

In order to enhance the retarding effect of concrete, the application provides super retarding concrete and a preparation method thereof.

In a first aspect, the application provides an ultra-retarding concrete, which adopts the following technical scheme:

the super-retarding concrete comprises the following raw materials in parts by weight:

300-350 parts of cement;

70-80 parts of mineral powder;

45-55 parts of fly ash;

950-1050 parts of coarse aggregate;

700-800 parts of fine aggregate;

1.5-4 parts of a retarder;

2-5 parts of a reinforcing agent;

1-3 parts of gypsum powder;

0.8-1.2 parts of vegetable oil;

1-3 parts of a water reducing agent;

150-200 parts of water;

the retarder consists of soybean protein and sodium pyrophosphate, and the weight ratio of the soybean protein to the sodium pyrophosphate is 1 (1-2).

By adopting the technical scheme, substances such as retarder, gypsum powder, vegetable oil, reinforcing agent and the like are added to jointly act to improve the retarding effect of the concrete; the retarder is preferably a mixture of soy protein and sodium pyrophosphate, and the weight ratio of the soy protein to the sodium pyrophosphate is preferably selected, so that the soy protein is rich in protein content, and the retarder is compounded with the sodium pyrophosphate to effectively retard the concrete; the gypsum powder is matched with the retarder and the reinforcing agent, and the hydration process is delayed by reducing the contact area of cement and water, so that the retarding effect of concrete is further improved; the vegetable oil, the retarder and the gypsum powder are matched with each other, so that the retarding effect is enhanced, meanwhile, the vegetable oil and the retarder are dispersed, the retarding effect of concrete is further enhanced, and the setting time of the concrete is prolonged.

Preferably, the reinforcing agent comprises at least one of graphene and vanadium slag.

By adopting the technical scheme, the reinforcing agent is preferably one or two of graphene and vanadium slag, so that the reinforcing agent further blocks the hydration of cement, the delayed coagulation effect of concrete is further enhanced, and in addition, the reinforcing agent and the concrete are combined with mineral powder and other substances after being added into the concrete, the strength of the concrete is improved, and the concrete has better mechanical properties.

Preferably, the vegetable oil comprises at least one of rapeseed oil and peanut oil.

Through adopting above-mentioned technical scheme, one or two in vegetable oil preferred rapeseed oil, peanut oil, with retarder, the better cooperation of gypsum, further the retardation effect of reinforcing concrete, the setting time of extension concrete.

Preferably, the raw materials of the ultra-retarding concrete also comprise 1-2 parts by weight of an accelerant, and the accelerant comprises at least one of palygorskite powder and sodium bentonite.

By adopting the technical scheme, the accelerator consisting of one or two of palygorskite powder and sodium bentonite is added, and the retarder and the gypsum powder are combined with each other, so that the adsorption performance is improved, the cement hydration is blocked, the retarding effect of the concrete is further improved, and the setting time of the concrete is prolonged; meanwhile, after the adhesive is added into concrete, the concrete is endowed with better adhesive property, the strength of the concrete is enhanced, and the condition of concrete segregation is reduced.

Preferably, the gypsum powder comprises at least one of desulfurized gypsum powder and citric acid gypsum powder.

By adopting the technical scheme, the gypsum powder is preferably one or two of desulfurized gypsum powder and citric acid gypsum powder, and the retarder and the reinforcing agent are better matched, so that the hydration of cement is further delayed, and the setting time of concrete is prolonged.

Preferably, the gypsum powder consists of desulfurized gypsum powder and citric acid gypsum powder, and the weight ratio of the desulfurized gypsum powder to the citric acid gypsum powder is 1 (1-1.5).

By adopting the technical scheme, the proportion of the desulfurized gypsum powder and the citric acid gypsum powder in the gypsum powder is optimized, and the super-retarding concrete with excellent retarding effect is obtained.

Preferably, the water reducing agent is a lignosulfonate water reducing agent.

By adopting the technical scheme, the lignosulfonate water reducing agent is preferably selected to be matched with the retarder, the initial hydration of the cement is inhibited, and the segregation resistance of the concrete is enhanced through the dispersion and other effects.

In a second aspect, the application provides a preparation method of super-retarding concrete, which adopts the following technical scheme:

a preparation method of super-retarding concrete comprises the following steps:

s1, mixing 30-50 parts by weight of water, coarse aggregate, fine aggregate, fly ash and mineral powder, adding cement, the balance of water and a water reducing agent after uniformly mixing, and obtaining a first mixture after uniformly mixing;

and S2, mixing the first mixture with a retarder, a reinforcing agent, gypsum and vegetable oil, and uniformly mixing to obtain the super-retarding concrete.

By adopting the technical scheme, the raw materials of the ultra-retarding concrete are uniformly mixed step by step, the water adding amount is reduced, the cement hydration process is reduced, and the concrete is endowed with better retarding performance, strength and segregation resistance.

Preferably, an accelerator is added in the step S2, and the retarder, the reinforcing agent, the gypsum and the vegetable oil are mixed together.

By adopting the technical scheme, the accelerator is added in the step S2, and is uniformly mixed with other additives, gypsum, vegetable oil and the like, so that the concrete with good retardation effect and segregation resistance is obtained.

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

1. as the retarder, the gypsum powder, the vegetable oil, the reinforcing agent and other substances are added and matched with each other, the retarding effect of the concrete is enhanced together; the retarder is preferably prepared by mixing soy protein and sodium pyrophosphate, and is compounded with the reinforcing agent and the gypsum powder, so that the retarder can effectively retard concrete, and simultaneously endows the concrete with better strength and segregation resistance.

2. In the application, the reinforcing agent is preferably one or two of graphene and vanadium slag, so that the hydration of cement is further shielded, and the delayed coagulation effect of concrete is enhanced; the formula of the vegetable oil is optimized, one or two of the rapeseed oil and the peanut oil are selected to be better matched with the retarder and the gypsum, and the setting time of the concrete is further prolonged.

3. According to the method, specific components of the gypsum powder are optimized, one or two of the desulfurized gypsum powder and the citric acid gypsum powder are selected, and the proportion of the desulfurized gypsum powder and the citric acid gypsum powder is optimized, so that the desulfurized gypsum powder and the citric acid gypsum powder are better matched with a retarder and a reinforcing agent, the hydration of cement is delayed, and the setting time of concrete is further prolonged; one or two of palygorskite powder and sodium bentonite are added as an accelerant, and a retarder and gypsum are matched to block the hydration of cement, so that the concrete has better retarding effect and is endowed with better strength and segregation resistance.

Detailed Description

The present application is described in further detail below.

The components and manufacturers in the examples are shown in Table 1.

TABLE 1 Components and manufacturers

Examples

Example 1:

the super-retarding concrete comprises the following specific components in percentage by weight as shown in Table 2, and is prepared by the following steps:

s1, mixing and stirring part of water, coarse aggregate, fine aggregate, fly ash and mineral powder at a stirring speed of 800r/min, adding cement, the balance of water and a water reducing agent after uniformly stirring, mixing and stirring at a stirring speed of 800r/min, and uniformly stirring to obtain a first mixture; and S2, mixing and stirring the first mixture, the retarder, the reinforcing agent, the gypsum and the vegetable oil at the stirring speed of 1000r/min, and uniformly stirring to obtain the super-retarding concrete.

Example 2 an ultra-retarded concrete, which is different from example 1 in specific components and weights, was included as shown in table 2.

Examples 3-4 a super set retarding concrete, which is different from example 1 in the components of the reinforcing agent, and includes specific components and weights as shown in table 2.

Examples 5 to 6A super set retarding concrete is different from example 1 in that the components of the vegetable oil are different, and the specific components and weights thereof are shown in Table 2.

Examples 7 to 8 an ultra-retarded concrete, which is different from example 1 in that an accelerator was added in step S2, and the concrete components and weights thereof are shown in Table 2.

TABLE 2 specific compositions and weights of examples 1-8

Examples 9 to 10, an ultra-retarding concrete, which is different from example 1 in the specific components and weight of gypsum powder, is included as shown in table 3.

Examples 11 to 12: an ultra-retarding concrete, which is different from the concrete of example 10 in the specific components and weights of the gypsum powder, is included as shown in Table 3.

Examples 13-14A super set retarding concrete, which differs from example 1 in the components of the water reducing agent, and includes the specific components and weights shown in Table 3.

Examples 15 to 16 ultra-retarded concrete, comprising the specific components and weights shown in table 3, was prepared by the following steps:

s1, mixing and stirring part of water, coarse aggregate, fine aggregate, fly ash and mineral powder at a stirring speed of 800r/min, adding cement, the balance of water and a water reducing agent after uniformly stirring, mixing and stirring at a stirring speed of 800r/min, and uniformly stirring to obtain a first mixture;

and S2, mixing and stirring the first mixture, a retarder, a reinforcing agent, gypsum, vegetable oil and an accelerator at the stirring speed of 1000r/min, and uniformly stirring to obtain the ultra-retarding concrete.

TABLE 3 specific compositions and weights of examples 9-16

Comparative example

Comparative example 1A concrete was obtained, which was different from example 1 in that no soybean protein was contained in the retarder.

Comparative example 2 a concrete, which differs from example 1 in that the retarder does not contain sodium pyrophosphate.

Comparative example 3 a concrete, which differs from example 1 in that it does not contain a retarder.

Comparative example 4 a concrete, which differs from example 1 in that it does not contain vegetable oil.

Comparative example 5A concrete, which differs from example 1 in that it does not contain vegetable oil and a retarder.

Comparative example 6A concrete consisting of the following components: 100 parts of cement, 50 parts of composite admixture, 80 parts of ceramic sand with the particle size of 1mm, 250 parts of broken stone, 1.3 parts of composite additive and 30 parts of water; wherein the composite admixture comprises the following raw materials in parts by weight: 35 parts of limestone with the grain size of 0.7mm and 15 parts of fly ash with the grain size of 0.3 mm; the raw materials of the composite additive comprise: the water reducer comprises a naphthalene-based high-efficiency water reducer, sodium gluconate, maltose cyclodextrin and a plasticizer, wherein the weight ratio of the naphthalene-based high-efficiency water reducer to the sodium gluconate to the maltose cyclodextrin to the plasticizer is 1:0.15:0.1:0.2; the weight ratio of the fine crushed stones to the coarse crushed stones in the crushed stones is 1.5:8.5, wherein the particle size of the fine crushed stone in the crushed stone is 8mm, and the particle size of the coarse crushed stone is 25m. Wherein the cement is from Portland cement PO42.5 grade of Shandong Tegu new building materials Co., ltd, and the ceramic sand is from Roche building materials Ming & Ying Ming in Yangmen region; crushed stone was obtained from Yixing Fushengda building materials Co., ltd; the naphthalene series high-efficiency water reducing agent is from Nantong Jinyuan dyeing Co., ltd, and the model is 1071; the sodium gluconate is from Jinan Ming chen environmental protection science and technology Limited and has the model of MC-sodium gluconate; the maltose cyclodextrin is from Wuhan Prov Biotechnology GmbH, model 256374; the plasticizer is polyester plasticizer UN610 from Kunrui chemical Co., ltd.

The preparation method comprises the following steps: mixing and stirring cement, composite admixture, ceramic sand, broken stone, composite additive and water at the stirring speed of 1000r/min, and uniformly stirring to obtain the concrete.

Detection method

Experiment one: experimental sample of setting retardation: the concrete prepared in examples 1 to 16 and comparative examples 1 to 6 were used, and the concrete obtained in examples 1 to 16 was named as experimental samples 1 to 16, respectively, and the concrete obtained in comparative examples 1 to 6 was named as comparative samples 1 to 6, respectively, and 5 of the experimental samples 1 to 16 and the comparative samples 1 to 6 were used.

An experimental instrument: a moisture curing box (model WJ-HW-405 from Hangzhou Wujia mechanical devices, inc.), a timekeeping watch (model SP-18195-NTP from Shenzhen Shenzhou Xunpeng technology, inc.).

The experimental method comprises the following steps: the setting times of the experimental samples 1-16 and the comparative samples 1-6 were tested with reference to GB/T1346-2019, cement Standard consistency, setting time, stability test method.

The experimental results are as follows: the results of the retardation experiments for the experimental samples 1 to 16 and the comparative samples 1 to 6 are shown in Table 4.

Experiment two: experimental sample of compressive strength: examples 1 to 16 and comparative examples 1 to 6 were formed into cubes having a side length of 150mm, the cubes formed in examples 1 to 16 were designated as experimental samples 1 to 16, respectively, and the cubes formed in comparative examples 1 to 6 were designated as comparative samples 1 to 6, respectively.

An experimental instrument: compression testing machine (manufactured by Olai machinery of Shandong, model AL-589).

The experimental method comprises the following steps: the compressive strength of the high-permeability concrete is evaluated according to a compressive strength experiment in the experimental method standard of concrete physical and mechanical properties of national standard GB/T50081-2019, and the specific compressive strength experiment steps are as follows: when the experimental sample reaches the experimental age, namely 28 days, taking out the experimental sample from the maintenance place, placing the experimental sample in front of a compression-resistant experimental machine, and wiping the surface of the experimental sample and the upper and lower bearing plate surfaces clean; the side surface of the experimental sample during molding is taken as a pressure bearing surface. The experimental sample is placed on a lower pressing plate or a base plate of the compression testing machine, and the center of the experimental sample is aligned with the center of the lower pressing plate of the compression testing machine. And starting the compression test machine, and uniformly contacting the surface of the test sample 1 with the upper and lower bearing plates or the steel base plate. In the experimental process, the load is continuously and uniformly added, and the loading speed is 0.3MPa/s-1.0MPa/s. When the compressive strength of the experimental sample is less than 30MPa, the loading speed is preferably 0.3MPa/s-0.5MPa/s; when the compressive strength of the experimental sample is 30-60MPa, the loading speed is preferably 0.5-0.8 MPa/s; when the compressive strength of the experimental sample is not less than 60MPa, the loading speed is preferably 0.8MPa/s-1.0MPa/s. When the loading speed of the compression testing machine is manually controlled, when the test sample is close to the damage and begins to deform rapidly, stopping and adjusting the accelerator of the compression testing machine until the test sample is damaged, recording the damage load at the moment, and calculating the compression strength of the test sample.

The test samples 1 to 16 and the comparative samples 1 to 6 were subjected to the compressive strength test in accordance with the above test methods.

The experimental results are as follows: the results of the compression strength test of the experimental samples 1 to 16 and the comparative samples 1 to 6 are shown in Table 4.

Experiment three: experimental sample of anti-segregation property: respectively adopt 0.02m ³ Examples 1-16 and comparative examples 1-6, and designated experimental samples 1-16 and comparative samples 1-6, respectively, with 5 each of experimental samples 1-16 and comparative samples 1-6.

An experimental instrument: jumping table (amplitude 25 + -2 mm), spatula (1.5 inch from Ministry of Shanghai Kangtian adhesive product), 5mm sieve, platform scale (Suzhou Shunquan mechanical equipment, inc., model XK 3100), balance (Shanghai Jingqiang mechanical equipment, inc., model YP 30001), sponge, and hopper (Henan Shasho mechanical equipment, inc., model JB-350).

The experimental method comprises the following steps: according to a mixture stability table-jumping experiment in self-compacting concrete design and construction guide of CCES02-2004 standard of China civil engineering society, the segregation rates of the experimental samples 1-16 and the comparative samples 1-6 are respectively detected; for example, recording and calculating the segregation rate of the experimental sample 1, for example, calculating the segregation rates of 5 experimental samples 1 respectively, and taking the average value of the segregation rates of 5 experimental samples 1 as the final segregation rate of the experimental sample 1; the above-described method was used to perform the isolation rate experiments on the experimental samples 2 to 16 and the comparative samples 1 to 6.

The experimental results are as follows: the results of the segregation rates of the experimental samples 1 to 16 and the comparative samples 1 to 6 are shown in Table 4

TABLE 4 results of the experiments of the experimental samples 1 to 16 and the comparative samples 1 to 6

As can be seen from the experimental data in Table 4, the initial setting time of the experimental samples 1 to 16 is 4729 to 5018min, the final setting time is 5418 to 5768min, the compressive strength of 28d is 47.6 to 55.3MPa, and the segregation rate is 3.4 to 6.5%; comparative examples 1 to 6 had initial setting times of 3679 to 4535min and final setting times of 4305 to 5198min, compressive strengths of 28d of 39.9.6 to 46.1MPa and segregation rates of 7.4 to 11.3%; compared with comparative examples 1 to 6, the experimental samples 1 to 16 have the advantages of better retardation, high compressive strength and low segregation rate.

Comparing the experimental sample 1 and the comparative samples 1 to 3, it can be known that the addition of the retarder consisting of the soy protein and the sodium pyrophosphate is helpful to prolong the retardation time; the soybean protein and inorganic sodium pyrophosphate are mutually matched, and the delayed coagulation time is prolonged and the influence on the strength of concrete is small through the adsorption and colloid protection effects of the protein and the sodium pyrophosphate; contrast experiment sample 1 and contrast sample 3-5 can know, and vegetable oil and retarder cooperation also can delay the setting time, improve compressive strength simultaneously, reduce the segregation degree of concrete.

Comparing the experimental sample 1 with the experimental samples 3-4, it can be seen that after the reinforcing agent is preferably selected from at least one of graphene and vanadium slag, the concrete has better retardation effect and high strength; probably, the two agents change the surrounding environment of cement hydration particles by participating in cement hydration reaction, thereby prolonging the setting time of cement. Comparing the experimental sample 1 with the experimental samples 5-6, the preferable formula of the vegetable oil is beneficial to enhancing the retarding effect of the concrete, probably because the vegetable oil is matched with the retarder, the retarder is uniformly dispersed in the concrete, and the setting time is prolonged; comparing the experimental sample 1 with the experimental samples 7-8, it can be known that after the accelerator palygorskite powder and the sodium bentonite are added, the concrete retardation time is prolonged, the segregation rate is low, probably because the palygorskite powder and the sodium bentonite have good adsorption capacity and rheological property and strong binding capacity, the retardation is formed by hydrating cement, so that the retardation effect of the concrete is further improved, the setting time of the concrete is prolonged, the strength of the concrete is improved, and the segregation problem is reduced; comparing the experimental sample 1 with the experimental samples 9-10, it can be seen that at least one of desulfurized gypsum powder and citric acid gypsum powder is preferably used as gypsum powder, ettringite is generated by hydration of sulfate radicals in gypsum and cement, the ettringite is attached to the surface of the cement, the contact area between the cement and water is reduced, and the retardation time is further prolonged; comparing the experimental samples 10-12, the preferable weight ratio of the desulfurized gypsum powder to the citric acid gypsum powder in the gypsum powder better matches the retarder, and the retarding time of the concrete is prolonged; comparing the experimental sample 1 with the experimental samples 13-14, the water reducing agent is preferably a lignosulfonate water reducing agent, so that the strength of the concrete can be improved, the water reducing agent inhibits the initial hydration of the cement, the fluidity of the cement paste is improved, and the segregation rate is reduced; comparing the experimental sample 1 with the experimental samples 15-16, it can be seen that by optimizing the formula of each raw material, the ultra-retarded concrete with good retarding effect, high compressive strength and small segregation rate can be obtained.

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

1. An ultra-retarding concrete is prepared by the following steps:

s1, mixing and stirring 50kg of water, 1050kg of coarse aggregate, 800kg of fine aggregate, 55kg of fly ash and 80kg of mineral powder at a stirring speed of 800r/min, adding 350kg of cement, 140kg of water and 3kg of lignosulfonate after uniformly stirring, mixing and stirring at a stirring speed of 800r/min, and uniformly stirring to obtain a first mixture;

s2, mixing and stirring the first mixture with 1kg of soybean protein, 2kg of sodium pyrophosphate, 2kg of graphene, 3kg of vanadium slag, 0.6kg of rapeseed oil, 0.5kg of peanut oil, 1kg of desulfurized gypsum powder, 1.5kg of citric acid gypsum powder, 1kg of palygorskite powder and 1kg of sodium bentonite at the stirring speed of 1000r/min, and uniformly stirring to obtain the ultra-retarding concrete.