Secondary fluidization first-aid agent for concrete and preparation method of secondary fluidization first-aid agent

Abstract

The invention discloses a secondary fluidization first-aid agent for concrete and a preparation method of the secondary fluidization first-aid agent, and relates to the field of constructional engineering materials. The secondary fluidization emergency agent is prepared from the following components in parts by weight: 180 to 220 parts of water reducing type polycarboxylic acid water reducing agent mother liquor, 90 to 110 parts of slow release type polycarboxylic acid water reducing agent mother liquor, 27 to 33 parts of amino water reducing agent, 9 to 11 parts of hydration heat inhibitor, 9 to 11 parts of water-based penetrating agent, 27 to 33 parts of viscosity reducer, 0.018 to 0.022 part of defoaming agent, 0.18 to 0.22 part of air entraining agent and 600 to 640 parts of water. The secondary fluidization emergency agent for the concrete can effectively reduce hydration heat, and has the advantages of being small in dosage, good in water reducing effect, full in slurry, low in viscosity, small in secondary slump loss, high in expansion degree, appropriate in initial setting time, low in strength loss after secondary fluidization of the concrete and the like.

Description

Technical Field

[0001] The invention belongs to the field of building engineering materials, and particularly relates to a secondary fluidization first aid agent for concrete and a preparation method thereof. Background Art

[0002] During the concrete transportation and pouring process, due to uncontrollable objective reasons such as traffic jams or sudden weather changes and slippery roads, the slump is lost over time, and secondary fluidization of the concrete is required. The use of traditional pumping agents during secondary fluidization not only has an insignificant fluidization effect, but also causes fluctuations in concrete performance due to the repeated addition of other components such as retarders and air entraining agents, such as strength loss, faster slump loss after fluidization, and even too long setting time, too high air content in concrete, and apparent porous surface due to excessive retarding components. In addition, the use of pumping agents for secondary fluidization is not economical; if water is added directly for fluidization, it will lead to loss of strength, easy to produce cracks and affect durability.

[0003] Chinese patent CN103214210A discloses a secondary fluidizer for concrete, which optimizes the formula of secondary fluidization to achieve better fluidization effect, but there are still two problems: (1) For construction site concrete that needs secondary fluidization, according to actual experience, when the slump of the construction concrete is appropriate, it is first mixed and then pumped. Finally, it takes about 40 minutes for the workers to vibrate the floor slab, finish the surface, and cover the film. The existing concrete that needs to be diluted is mixed evenly and the efficiency is low, which cannot guarantee the mixing speed and construction requirements; (2) When the secondary fluidizer is used, on the one hand, it will increase the slump of the concrete. On the other hand, there will still be a large amount of hydration heat, causing the mixer tank to become hot, accelerating the formation of calcium aluminate, and the softness of the concrete is difficult to meet the construction requirements of the site. It is easy to crack or even crack, affecting the durability. Summary of the invention

[0004] The object of the present invention is to provide a secondary fluidization first aid agent for concrete and a preparation method thereof, which not only has a short secondary fluidization time and a strong mixing effect, but also reduces the peak value of the hydration heat of concrete, delays the heat release time of the hydration heat of concrete, and can reduce the viscosity of the concrete system, which is beneficial to the operations of concrete mixing, pumping, vibrating, finishing, etc.

[0005] The technical solution adopted by the present invention to achieve the above-mentioned purpose is: A secondary fluidization first aid agent for concrete, consisting of the following components in parts by weight: 180-220 parts of water-reducing polycarboxylic acid water-reducing agent mother liquor, 90-110 parts of slow-release polycarboxylic acid water-reducing agent mother liquor, 27-33 parts of amino water-reducing agent, 9-11 parts of hydration heat inhibitor, 9-11 parts of water-based penetrant, 27-33 parts of viscosity reducer, 0.018-0.022 parts of defoaming agent, 0.18-0.22 parts of air entraining agent, and 600-640 parts of water.

[0006] As a preferred embodiment of the present invention, the hydration heat inhibitor is sulfonated tannin, amino acid condensation product, hydroxyethylidene diphosphonic acid HEDP, and sodium acetate trihydrate, and the mass ratio of sulfonated tannin: amino acid condensation product: hydroxyethylidene diphosphonic acid HEDP: sodium acetate trihydrate is (1-3):3:(2-4):(2-4).

[0007] As a preferred embodiment of the present invention, the aqueous penetrant is any one or more of sodium diisooctyl succinate, a condensate of fatty alcohol and ethylene oxide, isooctyl ether phosphate OEP-70, and a polyoxyethylene ether compound.

[0008] As a preferred embodiment of the present invention, the air entraining agent is any one or both of triterpenoid saponin and rosin thermal polymer.

[0009] As a preferred embodiment of the present invention, the viscosity reducer is selected from any one or more of a fluorine-containing hyperbranched polymer viscosity reducer, an organic phosphate polymer viscosity reducer, a maleic acid polyethylene glycol ester viscosity reducer, and an unsaturated carboxylic acid ester viscosity reducer.

[0010] As a preferred embodiment of the present invention, the defoaming agent is a polyether defoaming agent.

[0011] The present invention also provides a method for preparing a secondary fluidization first aid agent, comprising the following steps: firstly adding water, and then sequentially adding a hydration heat inhibitor, a water-reducing polycarboxylic acid-based water-reducing agent mother liquor, a slow-release polycarboxylic acid-based water-reducing agent mother liquor, an amino water-reducing agent, a viscosity reducer, a defoaming agent, and a water-based penetrant under low-speed stirring at 50-200 rpm, and then stirring at a medium speed of 201-350 rpm for 25-35 minutes, and finally adding an air entraining agent, and stirring at a low speed of 50-100 rpm for 8-12 minutes to obtain the secondary fluidization first aid agent for concrete.

[0012] Beneficial effects of the present invention: 1. The secondary fluidization first aid agent for concrete of the present invention saves time and accelerates the mixing speed by using a water-based penetrant. The viscosity reducer effectively reduces the viscosity of the concrete system, which is beneficial to actual operations such as stirring, pumping, vibrating, and finishing, and is more suitable for actual secondary fluidization operations.

[0013] 2. The secondary fluidization emergency agent for concrete of the present invention can selectively inhibit the early rapid hydration of C3A through the hydration heat inhibitor, which can significantly reduce the early hydration heat of cement, reduce the early maximum hydration heat peak, alleviate the temperature difference between the inside and outside of the concrete structure, make the inside and outside temperatures of the concrete almost the same, reduce or even avoid temperature cracks and shrinkage cracks, and fully hydrate C2S and C3S at the same time. Through the synergistic effect of the four, without affecting the hydration heat inhibition effect, not only the slow setting of the concrete before the secondary fluidization is significantly reduced, but also there is no negative impact on the working state of the concrete after the secondary fluidization.

[0014] 3. The secondary fluidization first aid agent for concrete of the present invention is a liquid, which has the advantages of small dosage, good water reduction effect, reduced hydration heat, fast stirring penetration, ensuring that the strength of the concrete is basically intact after secondary fluidization, normal initial setting time, and small secondary slump loss. It can solve the problems of dryness and viscosity caused by excessive slump loss of concrete during secondary fluidization and concrete quality fluctuation caused by improper secondary fluidization method, especially in the long-distance transportation of concrete, encountering traffic jams or sudden weather changes and slippery roads and other uncontrollable objective reasons leading to the loss of slump over time. It has obvious practicality and economy under the condition of high quality requirements on construction sites. DETAILED DESCRIPTION

[0015] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0016] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. The singular forms "a", "an" and "the" used in the embodiments of the present application are also intended to include plural forms, unless the context clearly indicates other meanings.

[0017] The present application provides a secondary fluidization first aid agent for concrete, which is composed of the following components in parts by weight: 180-220 parts of water-reducing polycarboxylic acid water-reducing agent mother liquor, 90-110 parts of slow-release polycarboxylic acid water-reducing agent mother liquor, 27-33 parts of amino water-reducing agent, 9-11 parts of hydration heat inhibitor, 9-11 parts of water-based penetrant, 27-33 parts of viscosity reducer, 0.018-0.022 parts of defoaming agent, 0.18-0.22 parts of air entraining agent, and 600-640 parts of water.

[0018] Wherein, preferably, the hydration heat inhibitor is composed of sulfonated tannin, amino acid polycondensate, hydroxyethylidene diphosphonic acid HEDP, sodium acetate trihydrate, and the sulfonated tannin: The mass ratio of amino acid condensation polymer: hydroxyethylidene diphosphonic acid HEDP: sodium acetate trihydrate is (1-3):3:(2-4):(2-4). The amino acid condensation polymer begins to release in large quantities during the hydration acceleration period. Sodium acetate trihydrate is introduced into the hydration heat inhibitor to slow down the retarding time of concrete before secondary fluidization. Under a specific dosage, sodium acetate trihydrate can offset the retarding component of concrete before secondary fluidization. However, sodium acetate trihydrate begins to play a role in the early induction period of cement hydration, which will affect the working state of cement paste in the early induction period and is not conducive to the construction of concrete. By adding sulfonated tannins and hydroxyethylidene diphosphonic acid HEDP, after the cement is added with water (early induction period), the carboxyl group can quickly complex with calcium ions on the surface of cement particles and adsorb on the surface of cement particles to inhibit cement hydration, thereby reducing the effect of the introduction of sodium acetate trihydrate on the early working state of cement paste. The retarding component of concrete before secondary fluidization is tightly wrapped on the surface of cement particles in the hydration induction period, and at this time, the early strength effect has an effect of offsetting it.

[0019] The aqueous penetrant is any one or more of sodium diisooctyl succinate, a condensate of fatty alcohol and ethylene oxide, isooctyl ether phosphate OEP-70, and a polyoxyethylene ether compound.

[0020] The air entraining agent is any one or two of triterpenoid saponin and rosin thermal polymer.

[0021] The viscosity reducer is selected from any one or more of a fluorine-containing hyperbranched polymer viscosity reducer, an organic phosphate polymer viscosity reducer, a maleic acid polyethylene glycol ester viscosity reducer, and an unsaturated carboxylic acid ester viscosity reducer.

[0022] Preferably, the defoaming agent is a polyether defoaming agent.

[0023] The present application also provides a method for preparing the above-mentioned secondary fluidization first-aid agent for concrete, comprising the following steps: first adding water, and then sequentially adding a hydration heat inhibitor, a water-reducing polycarboxylic acid-based water-reducing agent mother liquor, a slow-release polycarboxylic acid-based water-reducing agent mother liquor, an amino water-reducing agent, a viscosity reducer, a defoaming agent, and a water-based penetrant under a low-speed stirring state of 50-200 rpm, and then stirring at a medium speed of 201-350 rpm for 25-35 minutes, and finally adding an air entraining agent, and stirring at a low speed of 50-100 rpm for 8-12 minutes to obtain the secondary fluidization first-aid agent for concrete.

[0024] The component ratio and preparation method of the secondary fluidization emergency agent for concrete provided in this application are usually carried out when the daily average temperature is 20°C. At other temperatures, the component ratio provided in this application needs to be adjusted accordingly. Example 1

[0025] The secondary fluidization first aid agent for concrete is composed of the following components in parts by weight: 200 parts of 40% mother liquor of water-reducing type P-TS3404 collapse-preserving polycarboxylic acid of Leizhi Group Kezhijie, 100 parts of 40% mother liquor of sustained-release P-T3404 collapse-preserving agent, 30 parts of amino water-reducing agent, 10 parts of hydration heat inhibitor, 10 parts of isooctyl ether phosphate OEP-70, 30 parts of fluorinated hyperbranched polymer viscosity reducer, 0.02 parts of polyether defoamer, 0.2 parts of triterpenoid saponin, and 620 parts of water; The hydration heat inhibitor is composed of sulfonated tannin, amino acid condensation product, hydroxyethylidene diphosphonic acid HEDP, and sodium acetate trihydrate, and the mass ratio of sulfonated tannin: amino acid condensation product: hydroxyethylidene diphosphonic acid HEDP: sodium acetate trihydrate is 1:3:2:2.

[0026] The preparation method of the secondary fluidization first-aid agent is as follows: firstly add 600g of water, start the stirrer at a low speed of 50-200 rpm, add 10 parts of hydration heat inhibitor, 200 parts of 40% mother liquor (water-reducing type) of P-TS3404 collapse-preserving polycarboxylic acid of Kezhijie of Leizhi Group, 100 parts of 40% mother liquor (slow-release type) of P-T3404 collapse-preserving agent, 30 parts of amino water reducer, 30 parts of fluorine-containing hyperbranched polymer viscosity reducer, 0.02 parts of polyether defoamer, 10 parts of isooctyl alcohol ether phosphate OEP-70, stir at a uniform speed for 30 minutes, finally add 0.2 parts of triterpenoid saponin, stir at a low speed of 50-100 rpm for 10 minutes to obtain a secondary fluidization first-aid agent for concrete with severe collapse damage. The whole preparation process follows the principle of hot elimination and cold introduction, elimination first and introduction later, and can eliminate harmful bubbles and introduce beneficial bubbles. Example 2

[0027] The secondary fluidization first aid agent for concrete is composed of the following components in parts by weight: 180 parts of 40% mother liquor of water-reducing Leizhi Group Kezhijie P-TS3404 collapse-preserving polycarboxylic acid, 110 parts of 40% mother liquor of sustained-release P-T3404 collapse-preserving agent, 27 parts of amino water-reducing agent, 9 parts of hydration heat inhibitor, 9 parts of sodium diisooctyl succinate sulfonate, 33 parts of maleic acid polyethylene glycol ester viscosity reducer, 0.018 parts of polyether defoamer, 0.18 parts of air entraining agent, and 600 parts of water; The hydration heat inhibitor is composed of sulfonated tannin, amino acid condensation product, hydroxyethylidene diphosphonic acid HEDP and sodium acetate trihydrate, and the mass ratio of sulfonated tannin: amino acid condensation product: hydroxyethylidene diphosphonic acid HEDP: sodium acetate trihydrate is 2:3:3:3.

[0028] The preparation method of the secondary fluidized first aid agent is the same as that of Example 1 except for the different component contents. Example 3

[0029] The secondary fluidization first aid agent for concrete is composed of the following components in parts by weight: 220 parts of 40% mother liquor of water-reducing type P-TS3404 collapse-preserving polycarboxylic acid of Kezhijie Group, 90 parts of 40% mother liquor of sustained-release P-T3404 collapse-preserving agent, 33 parts of amino water-reducing agent, 11 parts of hydration heat inhibitor, 11 parts of polyoxyethylene ether compound, 27 parts of organic phosphate polymer viscosity reducer, 0.022 parts of polyether defoamer, 0.22 parts of air entraining agent, and 640 parts of water; The hydration heat inhibitor is composed of sulfonated tannin, amino acid condensation product, hydroxyethylidene diphosphonic acid HEDP, and sodium acetate trihydrate, and the mass ratio of sulfonated tannin: amino acid condensation product: hydroxyethylidene diphosphonic acid HEDP: sodium acetate trihydrate is 3:3:4:4.

[0030] The preparation method of the secondary fluidized first aid agent is the same as that of Example 1 except for the individual components and dosages.

[0031] Comparative Example 1: The formula of the secondary fluidization first aid agent for concrete is different from that of Example 1 in that the hydration heat inhibitor is composed of sulfonated tannin, amino acid condensation product, and hydroxyethylidene diphosphonic acid HEDP, and the mass ratio of sulfonated tannin: amino acid condensation product: hydroxyethylidene diphosphonic acid HEDP is 2:3:3.

[0032] In the preparation method of the secondary fluidized first aid agent, except for the different formula of the secondary fluidized first aid agent, the preparation process and dosage are the same as those in Example 1.

[0033] Comparative Example 2: The formula of the secondary fluidization first aid agent for concrete is different from that of Example 1 in that no hydration heat inhibitor is used in this comparative example.

[0034] In the method for preparing the secondary fluidized first aid agent, except for the different formula of the secondary fluidized first aid agent, the preparation process is the same as that of Example 1.

[0035] The C30 concrete that has not been secondary fluidized in any way has a standard compressive strength of 33.8MPa after being compacted on a vibrating table for 28 days, but it does not meet the construction requirements, is difficult to compact, and has a hole when inserted. Taking the same batch of concrete as an example, the secondary fluidization first aid agent prepared by Examples 1-3 and Comparative Examples 1-2 of the present application is used to prepare concrete by secondary fluidization, and concrete is obtained by directly secondary fluidization with water, and concrete is obtained by secondary fluidization using traditional pumping agents and commercially available fluidizers, respectively. The performance index parameters of the obtained concrete are measured. During the measurement, the secondary fluidization causes the slump of the C30 concrete to be fluidized from 150mm to 210mm. The results of the various parameters are shown in Table 1.

[0036] Table 1 Concrete performance parameters Secondary fluidizing agent index Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 water Conventional pumping agents Commercially available fluidizers Secondary fluidization C30 required amount + water / kg / m3 1.5+2 1.6+2 1.4+2 1.6+2 1.6+2 0+13 4+7 2.0+3 Mixing time / min 1:40 1:50 1:40 2:00 2:10 2:30 3:20 3:00 Slump after secondary fluidization for 0.5h (same conditions, 20℃) / mm 210 205 205 200 195 140 150 190 Expansion after secondary fluidization for 0.5h / mm 530 530 530 520 510 410 430 490 Change in gas content after secondary fluidization for 0.5h / % +0.5 +0.5 +0.5 +0.5 +0.5 -2.0 +3.5 +2.0 Collapse and emptying time after secondary fluidization for 0.5h / S 5:30 5:40 5:40 6:00 6:05 7:00 8:40 7:20 C30 concrete state description The cohesion, water retention and fluidity are good, and the slurry is full. The cohesion, water retention and fluidity are good, and the slurry is full. The cohesion, water retention and fluidity are good, and the slurry is full. The cohesion, water retention and fluidity are good, and the slurry is full. The cohesion, water retention and fluidity are good, and the slurry is fuller. Water seepage, poor fluidity. No water seepage, poor fluidity and poor wrapping. No water seepage, good fluidity and good wrapping properties. C30 Temperature measurement after secondary fluidization / ℃ 33 34 33 36 41 45 49 48 Water reduction rate / % 29 29 29 27 27 23 25 26 Initial setting time / h 8:00 8:10 8:10 7:50 7:55 6:30 9:10 7:20 C30 concrete appearance Smooth surface Smooth surface Smooth surface Smooth surface Smoother surface There are cracks and a few harmful bubbles There are cracks and a small amount of harmful bubbles Cracks, smooth surface Concrete standard curing 28d compressive strength / MPa 33.8 33.7 33.8 33.3 33.0 28.2 30.1 31.3 Steel bar corrosion none none none none none Yes (adding water increases the gap) none none It can be seen from Table 1 that the secondary fluidization first aid agent obtained by the present invention has the advantages of small dosage, good water reduction effect, full slurry, reduced viscosity, small secondary slump loss, improved expansion, reduced hydration heat, appropriate initial setting time, minimal strength loss of concrete after secondary fluidization, and smooth concrete surface. Experiments have proved that the secondary fluidization first aid agent can also achieve the above effects by adding it to other concretes with strength grades of C30 and above and adjusting the dosage slightly.

[0037] It should be noted that the parts not described in detail herein are prior art, and the above embodiments are only used to illustrate the present invention, but the present invention is not limited to the above embodiments. Any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention fall within the protection scope of the present invention.

Claims

1. A secondary fluidization first aid agent for concrete, characterized in that: It is composed of the following components in parts by weight: 180-220 parts of water-reducing polycarboxylic acid water-reducing agent mother liquor, 90-110 parts of slow-release polycarboxylic acid water-reducing agent mother liquor, 27-33 parts of amino water-reducing agent, 9-11 parts of hydration heat inhibitor, 9-11 parts of water-based penetrant, 27-33 parts of viscosity reducer, 0.018-0.022 parts of defoaming agent, 0.18-0.22 parts of air entraining agent, and 600-640 parts of water.

2. A secondary fluidization first aid agent for concrete as claimed in claim 1, characterized in that: The hydration heat inhibitor is sulfonated tannin, amino acid polycondensate, hydroxyethylidene diphosphonic acid HEDP, and sodium acetate trihydrate, and the mass ratio of sulfonated tannin: amino acid polycondensate: hydroxyethylidene diphosphonic acid HEDP: sodium acetate trihydrate is (1-3):3:(2-4):(2-4).

3. A secondary fluidization first aid agent for concrete as claimed in claim 1, characterized in that: The aqueous penetrant is any one or more of sodium diisooctyl succinate, a condensate of fatty alcohol and ethylene oxide, isooctyl ether phosphate OEP-70, and a polyoxyethylene ether compound.

4. A secondary fluidization first aid agent for concrete as claimed in claim 1, characterized in that: The air entraining agent is any one or two of triterpenoid saponin and rosin thermal polymer.

5. A secondary fluidization first aid agent for concrete as claimed in claim 1, characterized in that: The viscosity reducer is selected from any one or more of a fluorine-containing hyperbranched polymer viscosity reducer, an organic phosphate polymer viscosity reducer, a maleic acid polyethylene glycol ester viscosity reducer, and an unsaturated carboxylic acid ester viscosity reducer.

6. A secondary fluidization first aid agent for concrete as claimed in claim 1, characterized in that: The defoamer is a polyether defoamer.

7. The method for preparing the secondary fluidized first aid agent according to any one of claims 1 to 6, characterized in that: The method comprises the following steps: firstly adding water, and then sequentially adding a hydration heat inhibitor, a water-reducing polycarboxylic acid water-reducing agent mother liquor, a slow-release polycarboxylic acid water-reducing agent mother liquor, an amino water-reducing agent, a viscosity reducer, a defoaming agent, and a water-based penetrant under a low-speed stirring state of 50-200 rpm, and then stirring at a medium speed of 201-350 rpm for 25-35 minutes, and finally adding an air entraining agent, and stirring at a low speed of 50-100 rpm for 8-12 minutes to obtain the secondary fluidization first-aid agent for concrete.