阅读说明：本技术 一种高速公路路基缓凝水泥及其制备方法 (Retarding cement for highway subgrade and preparation method thereof ) 是由 辛艳 赵群 苗波涛 于 2021-11-19 设计创作，主要内容包括：本发明提供一种高速公路路基缓凝水泥,所述缓凝水泥按质量份计,包括以下组分：硅酸盐水泥熟料65-75份、硼砂4-6份、环氧树脂复合粉煤灰14-16份、烯丙基改性木质素磺酸钠2.5-3.5份、高炉矿渣2.5-3.5份、助磨剂0.15-0.25份。本发明还提供一种高速公路路基缓凝水泥的制备方法,所述制备方法包括制备环氧树脂复合粉煤灰、制备烯丙基改性木质素磺酸钠、制备缓凝水泥。本发明的缓凝水泥干缩性能优异,25d干缩率为0.041-0.044%,耐磨性能强,磨损量为0.86-0.89kg/m～(2)。(The invention provides retarding cement for a highway subgrade, which comprises the following components in parts by mass: 65-75 parts of silicate cement clinker, 4-6 parts of borax, 14-16 parts of epoxy resin composite fly ash, 2.5-3.5 parts of allyl modified sodium lignosulfonate, 2.5-3.5 parts of blast furnace slag and 0.15-0.25 part of grinding aid. The invention also provides a preparation method of the highway subgrade retarded cement, which comprises the steps of preparing the epoxy resin composite fly ash, preparing the allyl modified sodium lignosulfonate and preparing the retarded cement. The retarded cement of the invention has excellent drying shrinkage performance, 25d dry shrinkage of 0.041-0.044%, strong wear resistance, and wear loss of 0.86-0.89kg/m 2 。)

1. The slow-setting cement for the highway subgrade is characterized by comprising the following components in parts by mass: 65-75 parts of silicate cement clinker, 4-6 parts of borax, 14-16 parts of epoxy resin composite fly ash, 2.5-3.5 parts of allyl modified sodium lignosulfonate, 2.5-3.5 parts of blast furnace slag and 0.15-0.25 part of grinding aid.

2. The preparation method of the delayed coagulation cement for the highway subgrade is characterized by comprising the steps of preparing epoxy resin composite fly ash, preparing allyl modified sodium lignosulfonate and preparing delayed coagulation cement;

the preparation of the epoxy resin composite fly ash comprises primary modification and subsequent modification;

the preliminary modification comprises the steps of mixing dimethyl azodiisobutyrate and fly ash to obtain a mixture A, grinding and uniformly mixing the mixture A, grinding until the residue of a 0.045mm square-hole sieve is 7-9%, then mixing maleic anhydride and styrene to obtain a mixture B, grinding the mixture B and the mixture A under a heating condition, keeping the temperature at 70-80 ℃, and grinding until the residue of the 0.045mm square-hole sieve is 1.5-2.5%, thus obtaining the preliminary modified fly ash;

the mixture A comprises the following components in parts by mass: 0.8-1.2 parts of dimethyl azodiisobutyrate and 90-110 parts of fly ash;

the mixture B comprises the following components in parts by mass: 3.5-4.5 parts of maleic anhydride and 2.5-3.5 parts of styrene;

the mass ratio of the mixture A to the mixture B is 10: 9-11;

the subsequent modification comprises the steps of uniformly mixing the primarily modified fly ash, EP-20 epoxy resin and PA46 polyamide, curing and forming after mixing, and crushing after forming until the sieve residue of a 0.045mm square-hole sieve is 7-9%, thus obtaining the epoxy resin composite fly ash;

the mass ratio of the preliminary modified fly ash to the EP-20 epoxy resin to the PA46 polyamide is 9-11:2.5-3.5: 1.5-2.5;

dissolving sodium lignosulfonate and sodium hydroxide in deionized water to obtain a mixed solution, completely dissolving and filtering, heating the filtrate to 43-47 ℃, adding allyl bromide, stirring and reacting at 600r/min for 7-9h, performing rotary evaporation after the reaction is finished, filtering for 2-4 times by using an ultrafiltration membrane with the diameter of 0.04-0.06 mu m, and freeze-drying the filtrate to obtain the sodium allylmodified lignosulfonate;

the mixed solution comprises the following components in parts by mass: 4-6 parts of sodium lignosulphonate, 0.8-1.2 parts of sodium hydroxide and 450 parts of deionized water;

the mass ratio of the allyl bromide to the mixed solution is 1: 55-65.

3. The preparation method of the highway subgrade slow-setting cement according to claim 2, which is characterized by comprising the following steps:

the preparation of the retarded cement comprises the steps of uniformly mixing portland cement clinker, borax, epoxy resin composite fly ash, allyl modified sodium lignosulfonate and blast furnace slag, adding a grinding aid, and grinding to obtain the highway subgrade retarded cement.

4. The preparation method of the highway subgrade slow-setting cement according to claim 3, which is characterized by comprising the following steps:

the specific surface area of the delayed coagulation cement for the highway subgrade is 417-²/kg。

Technical Field

The invention relates to a retarding cement for a highway subgrade and a preparation method thereof, belonging to the technical field of cement.

Background

With the rapid development of the modern construction of highway traffic, the cement concrete pavement has become one of the development directions of road construction. The construction of the highway base course requires that the setting time of concrete is delayed, so that the construction operation is facilitated and the quality of the base course is ensured. In the construction season, usually in spring and summer, the temperature is high, the cement hydration speed is accelerated, the water evaporation is rapid, the concrete slump loss is accelerated, the fluidity is lost rapidly, the construction is difficult or the construction quality of a base layer is influenced, so that the concrete construction is required to have longer working time. Meanwhile, the early cracks of the base layer caused by the temperature difference can be effectively reduced by prolonging the setting time of the concrete.

At present, most of the retarding cement products of domestic retarding cement mainly meet the requirements of highway construction and technical requirements, the initial setting time is more than 3 hours, and the requirements that the initial setting time is more than 4 hours and the final setting time is more than 6 hours cannot be met.

CN102173612A discloses a retarding cement for highway subgrade, belonging to fly ash silicate cement, which improves retarding time by fly ash retarding action and adding commercial retarder, prolongs initial setting time to 4 hours and final setting time to more than 6 hours, but because the content of fly ash is high, the cement structure is loose, so that the strength is not high, and the compressive strength and the flexural strength belong to the lowest grade, only 32.5 grade.

CN109608069A discloses 42.5-grade retarding cement, which is low in fly ash addition amount, small in cement fineness and capable of ensuring retarding time, but poor in dry shrinkage, easy to crack and poor in wear resistance.

In summary, the prior art has the following problems:

(1) the conventional retarding cement has poor shrinkage performance and is easy to crack under the condition of ensuring the strength and the slow setting performance, and cannot be well suitable for a highway subgrade as a subgrade cement material;

(2) the existing retarding cement has poor wear resistance and large abrasion after long-term use under the condition of ensuring the strength and the slow setting performance, and can not be well suitable for highway subgrade as a subgrade cement material.

Disclosure of Invention

The technical problem to be solved by the invention is to overcome the defects in the prior art, and the following aims are achieved by modifying the raw materials to prepare the retarded cement:

(1) the retarded cement has good shrinkage performance and is not easy to crack under the condition of ensuring the strength and the slow setting performance, and is suitable for the high-speed highway subgrade as a subgrade cement material;

(2) the retarded cement has good wear resistance and small abrasion after long-term use under the condition of ensuring the strength and the retarded cement performance, and is suitable for the highway subgrade as a subgrade cement material.

In order to solve the technical problems, the invention adopts the following technical scheme:

the slow-setting cement for the highway subgrade comprises the following components in parts by mass: 65-75 parts of silicate cement clinker, 4-6 parts of borax, 14-16 parts of epoxy resin composite fly ash, 2.5-3.5 parts of allyl modified sodium lignosulfonate, 2.5-3.5 parts of blast furnace slag and 0.15-0.25 part of grinding aid.

The following is a further improvement of the above technical solution:

the preparation method comprises the steps of preparing the epoxy resin composite fly ash, preparing the allyl modified sodium lignin sulfonate and preparing the retarded cement.

The preparation of the epoxy resin composite fly ash comprises primary modification and subsequent modification;

and the preliminary modification comprises the steps of mixing dimethyl azodiisobutyrate and fly ash to obtain a mixture A, grinding and uniformly mixing the mixture A, grinding until the residue of a 0.045mm square-hole sieve is 7-9%, then mixing maleic anhydride and styrene to obtain a mixture B, grinding the mixture B and the mixture A under a heating condition, keeping the temperature at 70-80 ℃, and grinding until the residue of the 0.045mm square-hole sieve is 1.5-2.5%, thus obtaining the preliminary modified fly ash.

The mixture A comprises the following components in parts by mass: 0.8-1.2 parts of dimethyl azodiisobutyrate and 90-110 parts of fly ash;

the mixture B comprises the following components in parts by mass: 3.5-4.5 parts of maleic anhydride and 2.5-3.5 parts of styrene;

the mass ratio of the mixture A to the mixture B is 10: 9-11.

And the subsequent modification comprises the steps of uniformly mixing the primarily modified fly ash, EP-20 epoxy resin and PA46 polyamide, curing and forming after mixing, and crushing after forming until the sieve residue of a 0.045mm square-hole sieve is 7-9%, thus obtaining the epoxy resin composite fly ash.

The mass ratio of the preliminary modified fly ash to the EP-20 epoxy resin to the PA46 polyamide is 9-11:2.5-3.5: 1.5-2.5.

The preparation method comprises the steps of dissolving sodium lignosulfonate and sodium hydroxide in deionized water to obtain a mixed solution, filtering after complete dissolution, adding allyl bromide when the filtrate is heated to 43-47 ℃, stirring and reacting for 7-9h at 600r/min under 400-47 ℃, performing rotary evaporation after the reaction is finished, filtering for 2-4 times by using an ultrafiltration membrane with the diameter of 0.04-0.06 mu m, and freeze-drying the filtrate to obtain the sodium allylmodified lignosulfonate.

The mixed solution comprises the following components in parts by mass: 4-6 parts of sodium lignosulphonate, 0.8-1.2 parts of sodium hydroxide and 450 parts of deionized water;

the mass ratio of the allyl bromide to the mixed solution is 1: 55-65.

The preparation of the retarded cement comprises the steps of uniformly mixing portland cement clinker, borax, epoxy resin composite fly ash, allyl modified sodium lignosulfonate and blast furnace slag, adding a grinding aid, and grinding to obtain the highway subgrade retarded cement.

The specific surface area of the delayed coagulation cement for the highway subgrade is 417-²/kg。

Compared with the prior art, the invention has the following beneficial effects:

the retarded cement has good retarding effect, the setting time is in accordance with the retarding requirement, the initial setting time is 397-405min, and the final setting time is 469-472min (GB 175-2007);

the slow setting cement has high compressive strength and flexural strength, wherein the compressive strength at 3d is 24.3-24.5MPa, the compressive strength at 28d is 55.1-55.4MPa, the flexural strength at 3d is 5.1-5.2MPa, and the flexural strength at 28d is 10.7-10.9MPa (GB 175-2007);

the retarded cement of the invention has excellent dry shrinkage performance, the dry shrinkage rate at 25d is 0.041-0.044% (JC/T603-1995);

the retarded cement of the invention has strong wear resistance, and the wear loss is 0.86-0.89kg/m²（JC/T 421）。

Detailed Description

Example 1

(1) Preparation of epoxy resin composite fly ash

a. Preliminary modification

Mixing dimethyl azodiisobutyrate and fly ash to obtain a mixture A, feeding the mixture A into a grinding machine, grinding and uniformly mixing until the residue of a 0.045mm square-hole sieve is 8%, then mixing maleic anhydride and styrene to obtain a mixture B, feeding the mixture B into the grinding machine, continuously grinding under a heating condition, keeping the temperature at 75 ℃, and grinding until the residue of the 0.045mm square-hole sieve is 2%, thus obtaining primarily modified fly ash;

the mixture A comprises the following components in parts by mass: 1 part of dimethyl azodiisobutyrate and 100 parts of fly ash;

the mixture B comprises the following components in parts by mass: 4 parts of maleic anhydride and 3 parts of styrene;

the mass ratio of the mixture A to the mixture B is 10: 10.

b. Subsequent modification

Uniformly mixing the preliminary modified fly ash, EP-20 epoxy resin and PA46 polyamide, curing and molding after mixing, feeding the molded mixture into a pulverizer to pulverize, and pulverizing until the sieve residue of a square-hole sieve with the diameter of 0.045mm is 8%, thereby obtaining epoxy resin composite fly ash;

the mass ratio of the preliminary modified fly ash to the EP-20 epoxy resin to the PA46 polyamide is 10:3: 2.

(2) Preparation of allyl modified sodium Lignosulfonate

Dissolving sodium lignosulfonate and sodium hydroxide in deionized water to obtain a mixed solution, completely dissolving, filtering, heating filtrate to 45 ℃, adding allyl bromide, stirring and reacting for 8 hours at 500r/min, performing rotary evaporation after the reaction is finished, removing unreacted allyl bromide, filtering for 3 times by using a 0.05 mu m ultrafiltration membrane, and freeze-drying the filtrate to obtain allyl modified sodium lignosulfonate;

the mixed solution comprises the following components in parts by mass: 5 parts of sodium lignosulphonate, 1 part of sodium hydroxide and 400 parts of deionized water;

the mass ratio of the allyl bromide to the mixed solution is 1: 60.

(3) Preparation of retarded cement

Uniformly mixing silicate cement clinker, borax, epoxy resin composite fly ash, allyl modified sodium lignin sulfonate and blast furnace slag, adding a grinding aid, and feeding into a cement mill for grinding to obtain highway roadbed delayed coagulation cement;

the slow setting cement for the highway subgrade comprises the following components in parts by mass: 70 parts of silicate cement clinker, 5 parts of borax, 15 parts of epoxy resin composite fly ash, 3 parts of allyl modified sodium lignosulfonate, 3 parts of blast furnace slag and 0.2 part of grinding aid;

the specific surface area of the slow setting cement for the highway subgrade is 420m²/kg。

The retarded cement of example 1 has good retarding effect, the setting time meets the retarding requirement, the initial setting time is 405min, and the final setting time is 472min (GB 175-2007);

the delayed coagulation cement of example 1 has high compressive strength and flexural strength, the 3d compressive strength is 24.5MPa, the 28d compressive strength is 55.4MPa, the 3d flexural strength is 5.2MPa, and the 28d flexural strength is 10.9MPa (GB 175-2007);

the retarded cement of example 1 has excellent dry shrinkage performance, and the dry shrinkage rate at 25d is 0.043% (JC/T603-;

the retarded cement of example 1 has high wear resistance with a wear loss of 0.86kg/m²（JC/T 421）。

Example 2

(1) Preparation of epoxy resin composite fly ash

a. Preliminary modification

Mixing dimethyl azodiisobutyrate and fly ash to obtain a mixture A, feeding the mixture A into a grinder, grinding and uniformly mixing until the balance of a 0.045mm square-hole sieve is 7%, then mixing maleic anhydride and styrene to obtain a mixture B, feeding the mixture B into the grinder, continuously grinding under a heating condition, keeping the temperature at 70 ℃, and grinding until the balance of the 0.045mm square-hole sieve is 1.5%, thus obtaining primarily modified fly ash;

the mixture A comprises the following components in parts by mass: 0.8 part of dimethyl azodiisobutyrate and 90 parts of fly ash;

the mixture B comprises the following components in parts by mass: 3.5 parts of maleic anhydride and 2.5 parts of styrene;

the mass ratio of the mixture A to the mixture B is 10: 9.

b. Subsequent modification

Uniformly mixing the preliminary modified fly ash, EP-20 epoxy resin and PA46 polyamide, curing and molding after mixing, feeding the molded mixture into a pulverizer to pulverize, and pulverizing until the sieve residue of a square-hole sieve with the diameter of 0.045mm is 7%, thereby obtaining epoxy resin composite fly ash;

the mass ratio of the preliminary modified fly ash to the EP-20 epoxy resin to the PA46 polyamide is 9:2.5: 1.5.

(2) Preparation of allyl modified sodium Lignosulfonate

Dissolving sodium lignosulfonate and sodium hydroxide in deionized water to obtain a mixed solution, completely dissolving, filtering, heating filtrate to 43 ℃, adding allyl bromide, stirring and reacting for 9 hours at 400r/min, performing rotary evaporation after the reaction is finished, removing unreacted allyl bromide, filtering for 2 times by using a 0.04 mu m ultrafiltration membrane, and freeze-drying the filtrate to obtain allyl modified sodium lignosulfonate;

the mixed solution comprises the following components in parts by mass: 4 parts of sodium lignosulphonate, 0.8 part of sodium hydroxide and 350 parts of deionized water;

the mass ratio of the allyl bromide to the mixed solution is 1: 55.

(3) Preparation of retarded cement

Uniformly mixing silicate cement clinker, borax, epoxy resin composite fly ash, allyl modified sodium lignin sulfonate and blast furnace slag, adding a grinding aid, and feeding into a cement mill for grinding to obtain highway roadbed delayed coagulation cement;

the slow setting cement for the highway subgrade comprises the following components in parts by mass: 65 parts of portland cement clinker, 4 parts of borax, 14 parts of epoxy resin composite fly ash, 2.5 parts of allyl modified sodium lignosulfonate, 2.5 parts of blast furnace slag and 0.15 part of grinding aid;

the specific surface area of the slow setting cement for the highway subgrade is 417m²/kg。

The retarded cement in the embodiment 2 has good retarding effect, the setting time meets the retarding requirement, the initial setting time is 397min, and the final setting time is 469min (GB 175-2007);

the delayed coagulation cement of example 2 has high compressive strength and flexural strength, the 3d compressive strength is 24.3MPa, the 28d compressive strength is 55.1MPa, the 3d flexural strength is 5.1MPa, and the 28d flexural strength is 10.7MPa (GB 175-2007);

the retarded cement of example 2 has excellent dry shrinkage performance, and the dry shrinkage rate of 25d is 0.041% (JC/T603-one 1995);

the retarded cement of example 2 has high wear resistance with a wear loss of 0.89kg/m²（JC/T 421）。

Example 3

(1) Preparation of epoxy resin composite fly ash

a. Preliminary modification

Mixing dimethyl azodiisobutyrate and fly ash to obtain a mixture A, feeding the mixture A into a grinder, grinding and uniformly mixing until the balance of a 0.045mm square-hole sieve is 9%, then mixing maleic anhydride and styrene to obtain a mixture B, feeding the mixture B into the grinder, continuously grinding under a heating condition, keeping the temperature at 80 ℃, and grinding until the balance of the 0.045mm square-hole sieve is 2.5%, thus obtaining primarily modified fly ash;

the mixture A comprises the following components in parts by mass: 1.2 parts of dimethyl azodiisobutyrate and 110 parts of fly ash;

the mixture B comprises the following components in parts by mass: 4.5 parts of maleic anhydride and 3.5 parts of styrene;

the mass ratio of the mixture A to the mixture B is 10: 11.

b. Subsequent modification

Uniformly mixing the preliminary modified fly ash, EP-20 epoxy resin and PA46 polyamide, curing and molding after mixing, feeding the molded mixture into a pulverizer to pulverize, and pulverizing until the sieve residue of a square-hole sieve with the diameter of 0.045mm is 9%, thereby obtaining epoxy resin composite fly ash;

the mass ratio of the preliminary modified fly ash to the EP-20 epoxy resin to the PA46 polyamide is 11:3.5: 2.5.

(2) Preparation of allyl modified sodium Lignosulfonate

Dissolving sodium lignosulfonate and sodium hydroxide in deionized water to obtain a mixed solution, completely dissolving, filtering, heating filtrate to 47 ℃, adding allyl bromide, stirring and reacting for 7 hours at 600r/min, performing rotary evaporation after the reaction is finished, removing unreacted allyl bromide, filtering for 4 times by using a 0.06 mu m ultrafiltration membrane, and freeze-drying the filtrate to obtain allyl modified sodium lignosulfonate;

the mixed solution comprises the following components in parts by mass: 6 parts of sodium lignosulphonate, 1.2 parts of sodium hydroxide and 450 parts of deionized water;

the mass ratio of the allyl bromide to the mixed solution is 1: 65.

(3) Preparation of retarded cement

Uniformly mixing silicate cement clinker, borax, epoxy resin composite fly ash, allyl modified sodium lignin sulfonate and blast furnace slag, adding a grinding aid, and feeding into a cement mill for grinding to obtain highway roadbed delayed coagulation cement;

the slow setting cement for the highway subgrade comprises the following components in parts by mass: 75 parts of portland cement clinker, 6 parts of borax, 16 parts of epoxy resin composite fly ash, 3.5 parts of allyl modified sodium lignosulfonate, 3.5 parts of blast furnace slag and 0.25 part of grinding aid;

the specific surface area of the slow setting cement for the highway subgrade is 423m²/kg。

The retarded cement of example 3 has good retarding effect, the setting time meets the retarding requirement, the initial setting time is 402min, and the final setting time is 470min (GB 175-2007);

the delayed coagulation cement of example 3 has high compressive strength and flexural strength, the 3d compressive strength is 24.4MPa, the 28d compressive strength is 55.2MPa, the 3d flexural strength is 5.1MPa, and the 28d flexural strength is 10.8MPa (GB 175-2007);

the retarded cement of example 3 has excellent dry shrinkage performance, the dry shrinkage at 25d is 0.044% (JC/T603-;

the retarded cement of example 3 has high wear resistance with a wear loss of 0.88kg/m²（JC/T 421）。