A low-water-heat bulk ferrite-aluminate cement concrete and a preparation method thereof

Abstract

The application belongs to the field of special concrete, and particularly relates to a low-water-heat large-volume ferrialuminate cement concrete and a preparation method thereof. Sand, ferrialuminate cement, fly ash, mineral powder, silica ash and limestone powder are put into a mixer, and stirred at a linear speed of 2-5 m / s for 0.4-0.5 h to obtain a first mixture; then water and an additive are put into the mixer, and stirred at a linear speed of 4-6 m / s for 30-40 s to obtain a uniform mortar; and then stones are put into the mixer, and stirred at a linear speed of 1-3 m / s for 50-60 s to obtain a low-water-heat large-volume ferrialuminate cement concrete mixture. The application is beneficial to reducing the risk of temperature cracks of the large-volume concrete, making the cementing material have better performance, reducing the heat release and heat release concentration of the large-volume concrete from the perspective of the aggregate, reducing the heat release concentration of the cement, and maximizing the combination with the aggregate, and being good for heat dissipation.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of high-performance building materials, and particularly relates to a low-hydraulic-heat mass ferrialuminate cement concrete and a preparation method thereof. BACKGROUND

[0002] The quality of construction projects is closely related to people's lives, not only related to people's life property safety, but also related to people's longing for a better life. Mass concrete is a relatively common construction technology in the construction industry, which meets the development characteristics of the construction industry. However, mass concrete is prone to have a large internal and external temperature difference due to its thick structure and large volume, and the temperature stress in the concrete increases, which causes temperature cracks in the concrete.

[0003] Ferrialuminate cement is a third series of cement independently developed in China, which is a hydraulic cementitious material prepared by calcining proper raw materials to obtain anhydrous calcium sulphoaluminate, iron phase and dicalcium silicate as main components, and adding a proper amount of gypsum and 0% to 10% limestone. It has high early strength, good frost resistance, corrosion resistance and wear resistance. Due to its excellent performance, it is often applied in the construction industry. Its high early strength is due to the fast reaction rate of anhydrous calcium sulphoaluminate, which also brings about a large early heat release of cement, and heat release is concentrated, which easily leads to temperature cracks in mass concrete pouring without taking measures.

[0004] Currently, there are related patents for mass concrete, such as CN110922122B and CN113493327B. CN110922122B mainly uses a large amount of mineral powder to replace cement, and CN113493327B mainly uses different retarders in cooperation. The above patents are all for ordinary portland cement, and are based on existing cement for control. There is no report on the preparation method of mass concrete for ferrialuminate cement. SUMMARY

[0005] The main purpose of the present application is to effectively reduce the temperature cracks generated in the molding and service stages of mass concrete, and provide a low-hydraulic-heat mass ferrialuminate cement concrete and a preparation method thereof.

[0006] The specific technical solution of the present application is:

[0007] A low-hydraulic-heat mass ferrialuminate cement concrete, by weight, comprises:

[0008] ferrialuminate cement: 240 to 370 parts;

[0009] fly ash: 40 to 135 parts;

[0010] mineral powder: 50 to 202.5 parts;

[0011] Silica fume: 10-15 parts;

[0012] Limestone powder: 40-70 parts;

[0013] Sand: 600-800 parts;

[0014] Stone: 850-1150 parts;

[0015] Water: 132-200 parts;

[0016] Admixtures: 5-9 parts.

[0017] Preferably, the ferrite cement mineral composition contains 30.0-45.0% of calcium sulphoaluminate, 30.0-40.0% of dicalcium silicate and 30.0-35.0% of ferrite, by weight percentage, and the fineness D90 is 10-15 μm. With the above ferrite cement mineral composition, the content of calcium sulphoaluminate is reduced and the content of dicalcium silicate is increased, compared with the traditional ferrite cement. Since calcium sulphoaluminate is the fastest reacting mineral phase in the ferrite cement and the early strength is mainly generated by the hydration of calcium sulphoaluminate to form ettringite, calcium sulphoaluminate is also the most exothermic mineral in the early reaction. Dicalcium silicate mainly reacts in the middle and later stages and the product is C-S-H gel, so the early exothermic amount of dicalcium silicate is low. Optimizing the ferrite cement mineral composition, a large volume concrete special ferrite cement with early exothermic amount reduced and middle and later stage sustained hydration is designed, which is beneficial to solve the heat release concentration from the cement point of view and improve the stability of the large volume concrete structure. The cement fineness is 10-15 μm, which can ensure good reactivity of the cement and avoid the reaction rate being too fast due to too small fineness, thereby causing heat release concentration, and control the reaction rate of the ferrite cement from the physical point of view, which has a positive significance for the hydration heat control of the low hydration heat large volume ferrite cement concrete.

[0018] Preferably, the fly ash is secondary fly ash with fineness D90 of 1-6 μm, and the mineral powder is S95 mineral powder with fineness D90 of 1-6 μm. The large amount of fly ash and mineral powder is used to replace the ferrite aluminate cement, on the one hand, the fly ash and mineral powder have low early reaction activity compared with the ferrite aluminate cement, and the ferrite aluminate cement has less calcium hydroxide due to the reaction of the minerals, and the solution pH is lower than that of the Portland cement, and the fly ash and mineral powder need a large amount of calcium hydroxide for reaction, so the early reaction degree of the fly ash and mineral powder is lower than that of the Portland cement. Therefore, the incorporation of the fly ash and mineral powder can reduce the overall early hydration heat of the concrete, and has a beneficial effect on the later strength. The fineness of the fly ash and mineral powder is 1-6 μm, and the ultra-fine treatment of the fly ash and mineral powder increases the specific surface area of the fly ash and mineral powder, so that the fly ash and mineral powder still have high reaction activity in the environment with insufficient alkalinity.

[0019] Preferably, the fineness of the silica powder is 0.1-0.3 μm, and the fineness of the limestone is 5-10 μm. The amount of the silica powder and limestone powder is relatively low, and the limestone powder is inactive, and the main purpose of the incorporation of the silica powder and limestone powder is to fill the voids between the cement and fly ash and mineral powder, and to achieve the closest packing from the perspective of the cementitious material. The ferrite aluminate cement, limestone powder, mineral powder and fly ash, and silica powder are matched with each other, and the four components basically form the closest packing inside the cementitious material, so as to improve the flow performance of the cementitious material as much as possible.

[0020] Preferably, the sand is natural sand with continuous gradation, and the stone is gravel with 5-25 mm continuous gradation. The continuous gradation of the aggregate ensures the flowability and strength, reduces the amount of cementitious material and water, and effectively reduces the cracking risk caused by the early heat release of the large-volume ferrite aluminate cement concrete.

[0021] Preferably, the water is cold water with a temperature range of 5-15 ℃. The use of cold water for mixing can reduce the cement reaction rate, and reduce the excessive heat release and heat release concentration of the concrete in the mixing process and early oxidation process.

[0022] Preferably, the admixture is a water reducing agent, a retarder and an air entraining agent, the water reducing agent is a polycarboxylic acid water reducing agent with a water reducing rate of 27%, the retarder is boric acid with a purity of ≥95%, and the air entraining agent is a non-ionic surfactant alkyl phenol ethylene oxide condensate. The water reducing agent, retarder and air entraining agent are 75%, 15% and 10% respectively. The three kinds of admixtures can effectively reduce the water consumption, control the heat release rate of the cementitious material, and ensure the flowability to meet the construction requirements of the large-volume concrete.

[0023] A preparation method of a low-hydration-heat large-volume ferrite aluminate cement concrete, comprising the following steps:

[0024] (1) Put sand, ferrite aluminate cement, fly ash, mineral powder, silica fume, and limestone powder into a mixer, and stir at a linear speed of 2-5 m / s for 0.4-0.5 h to obtain a first mixture;

[0025] (2) Put water and additives into the mixer, and stir at a linear speed of 4-6 m / s for 30-40 s to obtain uniform mortar;

[0026] (3) Put stones into the mixer, and stir at a linear speed of 1-3 m / s for 50-60 s to obtain a low-hydraulic-heat large-volume ferrite aluminate cement concrete mixture.

[0027] The low-hydraulic-heat large-volume ferrite aluminate cement concrete prepared through the above steps can better mix the cementing material and sand, and the addition of the additives and water before the addition of the stones can maximize the effect of the additives on the cement mortar, and at this time, the cement has reacted and part of the heat has been dissipated. The pre-mixed mortar and stones are fully mixed, so that the mortar and the coarse aggregate are maximally combined after being mixed uniformly. The large-volume ferrite aluminate cement concrete prepared through the above steps has good fluidity and mechanical strength, and the cracking risk is reduced.

[0028] The present application has the following advantages due to the use of the above technical solutions:

[0029] 1. The use of low-anhydrous calcium sulphoaluminate high-belite low-heat ferrite aluminate cement effectively reduces the excessively high hydration heat temperature and the heat release concentration caused by the cement itself, which is beneficial to reduce the temperature cracking risk of the large-volume concrete.

[0030] 2. The use of a large amount of superfine admixture to replace the ferrite aluminate cement reduces the excessively fast and concentrated hydration heat release of the cementing material while ensuring the strength of the concrete, and optimizes the gradation of the cementing material to make the cementing material have better performance.

[0031] 3. The use of reasonably graded sand, stone, and other aggregates optimizes the internal structure through physical methods, and reduces the amount of cementing material and water. From the perspective of the aggregate, the heat release and heat release concentration of the large-volume concrete are reduced.

[0032] 4. The use of cold water mixing reduces the early reaction rate of the cement from the perspective of the mixing water, and reduces the heat release concentration of the cement.

[0033] 5. The mixing method uses the pre-mixed mortar method, so that the cementing material can be maximally combined with the aggregate while ensuring the effect of the additives, and the heat dissipation is also beneficial.

[0034] The above description is only a summary of the technical solutions of the present application. In order to make the technical means of the present application clearer and to enable the present application to be implemented according to the content of the description, the preferred embodiments of the present application are described in detail as follows. DETAILED DESCRIPTION

[0035] In order to further clarify the technical means and effects taken by the present application to achieve the predetermined inventive objectives, the specific embodiments of a low-water-heat bulk ferrite aluminate cement concrete according to the present application are described in detail as follows in combination with the preferred embodiments. In addition, the specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0036] Embodiment 1

[0037] A low-water-heat bulk ferrite aluminate cement concrete, by weight, includes:

[0038] Ferrite aluminate cement: 370 parts;

[0039] Fly ash: 40 parts;

[0040] Mineral powder: 50 parts;

[0041] Silicon powder: 10 parts;

[0042] Limestone powder: 40 parts;

[0043] Sand: 800 parts;

[0044] Stone: 1050 parts;

[0045] Water: 200 parts;

[0046] Admixture: 5 parts.

[0047] The ferrite aluminate cement mineral composition contains 30.0-45.0% anhydrous calcium sulphoaluminate, 30.0-40.0% dicalcium silicate, and 30.0-35.0% calcium ferrite aluminate by weight percentage, and the fineness D90 is 10-15 μm.

[0048] The fly ash is secondary fly ash, the fineness D90 is 1-6 μm, the mineral powder is S95 mineral powder, and the fineness D90 is 1-6 μm.

[0049] The silicon powder fineness is 0.1-0.3 μm, and the limestone fineness is 5-10 μm.

[0050] The sand is natural sand, and the stone is crushed stone with 5-25 mm continuous gradation.

[0051] The water is cold water, and the temperature range is 5°C.

[0052] The admixture is water-reducing agent, retarder, air entraining agent, the water-reducing agent is polycarboxylic acid water-reducing agent, the water-reducing rate is 27%, the retarder is boric acid, the purity of boric acid is greater than or equal to 95%, the air entraining agent is non-ionic surfactant alkyl phenol ethylene oxide condensate, the water-reducing agent:retarder:air entraining agent is 75%:15%:10%.

[0053] A preparation method of a low hydration heat large volume ferrialuminate cement concrete, comprising the following steps:

[0054] (1) Put sand, ferrialuminate cement, fly ash, mineral powder, silica powder and limestone powder into a mixer, stir at a linear speed of 2 m / s for 0.5 h to obtain a first mixture;

[0055] (2) Put water and admixture into the mixer, stir at a linear speed of 4 m / s for 40 s to obtain uniform mortar;

[0056] (3) Put stone into the mixer, stir at a linear speed of 1 m / s for 60 s to obtain a low hydration heat large volume ferrialuminate cement concrete mixture.

[0057] Example 2

[0058] A low hydration heat large volume ferrialuminate cement concrete, comprising, by weight:

[0059] ferrialuminate cement: 300 parts;

[0060] fly ash: 135 parts;

[0061] mineral powder: 50 parts;

[0062] silica powder: 15 parts;

[0063] limestone powder: 70 parts;

[0064] sand: 600 parts;

[0065] stone: 1150 parts;

[0066] water: 200 parts;

[0067] admixture: 7 parts.

[0068] The ferrialuminate cement mineral composition contains, by weight percentage, 30.0-45.0% of anhydrous calcium sulphoaluminate, 30.0-40.0% of dicalcium silicate and 30.0-35.0% of calcium ferrialuminate, and the fineness D90 is 10-15 μm.

[0069] The fly ash is secondary fly ash, the fineness D90 is 1-6 μm, the mineral powder is S95 mineral powder, and the fineness D90 is 1-6 μm.

[0070] The fineness of the silica powder is 0.1-0.3 μm, and the fineness of the limestone is 5-10 μm.

[0071] The sand is natural sand with continuous gradation, and the stone is crushed stone with continuous gradation of 5-25 mm.

[0072] The water is cold water with a temperature range of 15°C.

[0073] The admixture is a water-reducing agent, a retarder, and an air-entraining agent, the water-reducing agent is a polycarboxylic acid water-reducing agent with a water-reducing rate of 27%, the retarder is boric acid with a purity of ≥95%, the air-entraining agent is a non-ionic surfactant alkyl phenol ethylene oxide condensate, and the water-reducing agent:retarder:air-entraining agent is 75%:15%:10%.

[0074] A preparation method of a low-hydraulic heat large-volume ferrialuminate cement concrete, comprising the following steps:

[0075] (1) The sand, ferrialuminate cement, fly ash, mineral powder, silica powder, and limestone powder are put into a mixer, and stirred at a linear speed of 5 m / s for 0.4 h to obtain a first mixture;

[0076] (2) The water and the admixture are further put into the mixer, and rapidly stirred at a linear speed of 6 m / s for 30 s to obtain a uniform mortar;

[0077] (3) The stone is further put into the mixer, and stirred at a linear speed of 3 m / s for 50 s to obtain a low-hydraulic heat large-volume ferrialuminate cement concrete mixture.

[0078] Example 3

[0079] A low-hydraulic heat large-volume ferrialuminate cement concrete, comprising, by weight:

[0080] ferrialuminate cement: 240 parts;

[0081] fly ash: 100 parts;

[0082] mineral powder: 202.5 parts;

[0083] silica powder: 13 parts;

[0084] limestone powder: 55 parts;

[0085] sand: 800 parts;

[0086] stone: 850 parts;

[0087] water: 132 parts;

[0088] admixture: 9 parts.

[0089] The ferrite-aluminate cement mineral composition contains 30.0-45.0% anhydrous calcium sulphoaluminate, 30.0-40.0% dicalcium silicate and 30.0-35.0% ferrite-aluminate calcium by weight percentage, and the fineness D90 is 10-15 μm.

[0090] The fly ash is a secondary fly ash, the fineness D90 is 1-6 μm, and the mineral powder is S95 mineral powder, the fineness D90 is 1-6 μm.

[0091] The silicon powder fineness is 0.1-0.3 μm, and the limestone fineness is 5-10 μm.

[0092] The sand is natural sand, continuous grading, and the stone is broken stone, 5-25 mm continuous grading.

[0093] The water is cold water, and the temperature range is 10 ℃.

[0094] The admixture is a water reducing agent, a retarder and an air entraining agent, the water reducing agent is a polycarboxylic acid water reducing agent, the water reducing rate is 27%, the retarder is boric acid, the boric acid purity is ≥95%, the air entraining agent is a non-ionic surfactant alkyl phenol ethylene oxide condensate, and the water reducing agent:retarder:air entraining agent is 75%:15%:10%.

[0095] A preparation method of a low hydration heat mass ferrite-aluminate cement concrete, comprising the following steps:

[0096] (1) the sand, ferrite-aluminate cement, fly ash, mineral powder, silicon ash and limestone powder are put into a mixer, and stirred at a linear speed of 3 m / s for 0.45 h to obtain a first mixture;

[0097] (2) the water and the admixture are further put into the mixer, and stirred at a linear speed of 5 m / s for 35 s to obtain uniform mortar;

[0098] (3) the stone is further put into the mixer, and stirred at a linear speed of 2 m / s for 55 s to obtain a low hydration heat mass ferrite-aluminate cement concrete mixture.

[0099] According to GB / T50496-2018 "Mass Concrete", the prepared low hydration heat mass concrete is tested in terms of mold temperature, inner and surface temperature difference, cooling rate and adiabatic temperature rise. The mold temperature is 18-25 ℃, the inner and surface temperature difference is 10-20 ℃, the cooling rate is 1-1.6 ℃, and the adiabatic temperature rise is 40-45 ℃. According to GB / T50081-2019 "Standard for Test Methods of Physical and Mechanical Properties of Concrete", the prepared low hydration heat mass concrete is tested in terms of 60 d compressive strength, and the concrete compressive strength is 47-60 MPa.

[0100] The above merely describes preferred embodiments of the present application, and is not used to limit the present application, any modification, equivalent replacement and improvement within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A low heat of hydration mass ferrite aluminate cement concrete, characterized in that, by weight, comprising: ferrite-aluminate cement: 240-370 parts; fly ash: 40-135 parts; mineral powder: 50-202.5 parts; silica powder: 10-15 parts; limestone powder: 40-70 parts; sand: 600-800 parts; stone: 850-1150 parts; water: 132-200 parts; additive: 5-9 parts; the ferrite-aluminate cement mineral composition contains 30.0-45.0% anhydrous calcium sulphoaluminate, 30.0-40.0% dicalcium silicate and 30.0-35.0% ferrite-aluminate by weight percentage, and the fineness D90 is 10-15 μm; the silica powder has a fineness of 0.1-0.3 μm; the limestone powder has a fineness of 5-10 μm.

2. A low heat of hydration mass ferrite aluminate cement concrete according to claim 1, characterized in that: the fly ash is a secondary fly ash, the fineness D90 is 1-6 μm, the mineral powder is S95 mineral powder, and the fineness D90 is 1-6 μm.

3. The low heat of hydration, high volume ferrite aluminate cement concrete according to claim 1, characterized in that: the sand is natural sand with continuous gradation.

4. The low heat of hydration, high volume ferrite aluminate cement concrete according to claim 1, characterized in that: the stone is crushed stone with 5-25 mm continuous gradation.

5. The low heat of hydration, high volume ferrite aluminate cement concrete according to claim 1, wherein: the water is cold water with a temperature range of 5-15 ℃.

6. A low heat of hydration mass ferrite aluminate cement concrete according to claim 1, characterized in that: the additive is water reducing agent, retarder and air entraining agent, the water reducing agent is polycarboxylic acid water reducing agent with a water reducing rate of 27%, the retarder is boric acid with a purity of ≥95%, and the air entraining agent is non-ionic surfactant alkyl phenol ethylene oxide condensate, the water reducing agent:retarder:air entraining agent is 75%:15%:10%.

7. A process for the production of a low heat of hydration bulk ferrialuminate cement concrete according to any one of claims 1 to 6, characterised in that comprising the following steps: (1) put sand, ferrite-aluminate cement, fly ash, mineral powder, silica powder and limestone powder into a mixer, stir at a linear speed of 2-5 m / s for 0.4-0.5 h to obtain a first mixture; (2) then put water and additive into the mixer, stir rapidly at a linear speed of 4-6 m / s for 30-40 s to obtain uniform mortar; (3) then put stone into the mixer, stir at a linear speed of 1-3 m / s for 50-60 s to obtain a low-hydraulic-heat large-volume ferrite-aluminate cement concrete mixture.