阅读说明：本技术 一种复合型混凝土缓凝剂及其制备方法 (Composite concrete retarder and preparation method thereof ) 是由 曾珣 陈杰 方世昌 邓妮 田应兵 于 2021-06-01 设计创作，主要内容包括：本发明公开了一种复合型混凝土缓凝剂及其制备方法,所述复合型混凝土缓凝剂由以下重量份配比的各组分制成：缓凝型减水剂50-70份,三元共聚物缓凝剂5-10份,有机膦酸类物质10-12份,无机磷酸类物质10-15份,糖类物质1-3份：缓凝型减水剂由以下重量份配比的各组分制成：不饱和聚醚类大单体90-120份,不饱和膦酸酯单体4-6份,不饱和羧酸类小单体7-13份,引发剂0.4-1.2份,还原剂0.1-0.4份,链转移剂0.3-0.6份,碱液；三元共聚物缓凝剂由以下重量份配比的各组分制成：不饱和羧酸小单体15-20份、不饱和酸酐15-20份,不饱和酯类小单体25-30份,引发剂0.6-1.5份,链转移剂0.1-0.4份,该复合型混凝土缓凝剂减水率高,缓凝性能好,适应性强,并且混凝土后期抗压强度无损失。(The invention discloses a composite concrete retarder and a preparation method thereof, wherein the composite concrete retarder is prepared from the following components in parts by weight: 50-70 parts of a retarding water reducer, 5-10 parts of a terpolymer retarder, 10-12 parts of an organic phosphonic acid substance, 10-15 parts of an inorganic phosphoric acid substance, and 1-3 parts of a saccharide substance: the retarding water reducer is prepared from the following components in parts by weight: 90-120 parts of unsaturated polyether macromonomer, 4-6 parts of unsaturated phosphonate monomer, 7-13 parts of unsaturated carboxylic acid small monomer, 0.4-1.2 parts of initiator, 0.1-0.4 part of reducing agent, 0.3-0.6 part of chain transfer agent and alkali liquor; the terpolymer retarder is prepared from the following components in parts by weight: 15-20 parts of unsaturated carboxylic acid small monomer, 15-20 parts of unsaturated anhydride, 25-30 parts of unsaturated ester small monomer, 0.6-1.5 parts of initiator and 0.1-0.4 part of chain transfer agent.)

1. A compound concrete retarder is characterized in that: the composite concrete retarder is prepared from the following components in parts by weight: 50-70 parts of a retarding water reducer, 5-10 parts of a terpolymer retarder, 10-12 parts of an organic phosphonic acid substance, 10-15 parts of an inorganic phosphoric acid substance and 1-3 parts of a saccharide substance;

the retarding water reducer is prepared from the following components in parts by weight: 90-120 parts of unsaturated polyether macromonomer, 4-6 parts of unsaturated phosphonate monomer, 7-13 parts of unsaturated carboxylic acid small monomer, 0.4-1.2 parts of initiator, 0.1-0.4 part of reducing agent, 0.3-0.6 part of chain transfer agent and alkali liquor;

the terpolymer retarder is prepared from the following components in parts by weight: 15-20 parts of unsaturated carboxylic acid small monomer, 15-20 parts of unsaturated anhydride, 25-30 parts of unsaturated ester small monomer, 0.6-1.5 parts of initiator and 0.1-0.4 part of chain transfer agent.

2. The composite concrete retarder according to claim 1, characterized in that: the organic phosphonic acid material is one or the combination of more than two of hydroxyethylidene diphosphonic acid (HEDP), amino trimethylene phosphonic Acid (ATMP), 2-phosphonic acid group-1, 2, 4-tricarboxylic acid butane (PBTCA), polyamino polyether methylene Phosphonic Acid (PAPEMP), 2-hydroxyphosphonoacetic acid (HPAA), ethylene diamine tetra methylene phosphonic acid (EDTMPS) and diethylenetriamine penta methylene phosphonic acid (DTPMPA).

3. The composite concrete retarder according to claim 1, characterized in that: the inorganic phosphoric acid substances are one or more of sodium tripolyphosphate, sodium pyrophosphate, sodium hexametaphosphate, disodium hydrogen phosphate and sodium dihydrogen phosphate.

4. The composite concrete retarder according to claim 1, characterized in that: the unsaturated polyether macromonomer is one or a combination of more than two of methyl allyl polyoxyethylene ether (HPEG) and isopentenyl polyoxyethylene ether (TPEG).

5. The composite concrete retarder according to claim 1, characterized in that: the unsaturated phosphonate monomer is one or the combination of more than two of allyl diethyl phosphonate and dimethyl vinyl phosphonate; the unsaturated carboxylic acid small monomer is one or the combination of more than two of maleic anhydride, acrylic acid, methacrylic acid and itaconic acid.

6. The composite concrete retarder according to claim 1, characterized in that: the initiator is one or the combination of more than two of ammonium persulfate, sodium persulfate, hydrogen peroxide, benzoyl peroxide or potassium persulfate.

7. The composite concrete retarder according to claim 1, characterized in that: the reducing agent is one or more of vitamin C, sodium sulfite, sodium bisulfite, potassium sulfite or sodium formaldehyde sulfoxylate.

8. The composite concrete retarder according to claim 1, characterized in that: the chain transfer agent is one or the combination of more than two of thioglycolic acid, mercaptopropionic acid, mercaptoethanol or sodium hypophosphite.

9. The composite concrete retarder according to claim 1, characterized in that: the unsaturated ester small monomer is one or a combination of more than two of dibutyl maleate and isopropyl maleate.

10. A preparation method of a compound concrete retarder is characterized by comprising the following steps:

(1) preparation of retarding water reducer

Dissolving 90-120 parts of polyether macromonomer in 100-120 parts of deionized water according to the proportion, stirring and dissolving into uniform and transparent solution, and adding 0.4-1.2 parts of initiator;

dissolving 7-13 parts of unsaturated carboxylic acid small monomer, 4-6 parts of unsaturated phosphonate monomer and 0.3-0.6 part of chain transfer agent in 10-13 parts of deionized water to prepare a dropping liquid A material for later use; dissolving 0.1-0.4 part of reducing agent in 18-22 parts of tap water to prepare a dropping liquid B material for later use;

at normal temperature, simultaneously adding the material A and the material B into the solution at a constant speed, wherein the dripping time is 3-3.5 hours, and after finishing the dripping, preserving the heat for 1 hour to finish the reaction;

adjusting the pH value to be neutral by using an alkali solution to obtain a transparent liquid, namely a retarding polycarboxylate superplasticizer;

(2) preparation of terpolymer retarder

Dissolving 15-20 parts of unsaturated anhydride in 25-30 parts of deionized water according to the proportion, introducing nitrogen for protection, and heating to raise the temperature to 80 ℃;

preparing a solution C from 15-20 parts of unsaturated carboxylic acid small monomer, 25-30 parts of unsaturated ester small monomer and 55-60 parts of deionized water; preparing solution D from 0.1-0.4 part of chain transfer agent and 25-30 parts of deionized water;

adding 0.6-1.5 parts of initiator into deionized water, dripping the solution C and the solution D simultaneously after 10 minutes, wherein the dripping time is 1-1.5 hours, cooling to 40 ℃ after finishing dripping, and preserving heat for 2 hours to finish reaction, wherein the obtained sample is the terpolymer retarder;

(3) the retarding water reducer, the terpolymer retarder, the organic phosphonic acid substances, the inorganic phosphoric acid substances and the saccharides are mixed to prepare the composite concrete retarder.

Technical Field

The invention relates to the technical field of concrete retarders, in particular to a composite concrete retarder and a preparation method thereof.

Background

With the rapid development of modern industry, the consumption of concrete is increasing, and the requirements of constructors on concrete additives are also increasing. Particularly, the temperature is high in summer, the setting time of concrete is shortened rapidly, and the fluidity is lost, so that inconvenience is brought to constructors. In the case of casting mass concrete, in order to reduce the construction accident that the concrete cracks due to the temperature stress generated by the heat release of hydration, it is necessary to extend the setting time of the concrete. The retarder is used as a common concrete additive and can influence the hydration reaction time of cement, thereby reducing the slump loss, maintaining the fluidity of concrete and prolonging the setting time of concrete. In addition, the retarder is added into the concrete, so that the aim of saving the using amount of cement can be achieved, and the durability of the concrete can be improved.

Inorganic retarders commonly used at present mainly comprise phosphates, borax and the like, and organic retarders comprise hydroxycarboxylic acids and salts thereof, saccharides and carbohydrates, lignosulfonate, polyhydric alcohols and derivatives thereof and the like. The substances have certain retardation effect, but the retardation effect of the single substance added is not good, and cannot meet the high requirements of modern industry, and the compatibility of the retarder with different types of cement, water reducing agent, mineral admixture and the like is poor due to different adsorption capacities of the materials, so that the development of the single retarder in concrete is limited. Therefore, the preparation of the concrete retarder with obvious coagulation effect and good compatibility is very important.

Disclosure of Invention

The technical problem to be solved by the invention is to overcome the existing defects, and provide the composite concrete retarder and the preparation method thereof, wherein the composite concrete retarder has the advantages of high water reducing rate, good retarding performance and strong adaptability, and can effectively solve the problems in the background art.

In order to achieve the purpose, the invention provides the following technical scheme: the composite concrete retarder is prepared from the following components in parts by weight: 50-70 parts of a retarding water reducer, 5-10 parts of a terpolymer retarder, 10-12 parts of an organic phosphonic acid substance, 10-15 parts of an inorganic phosphoric acid substance, and 1-3 parts of a saccharide substance:

the retarding water reducer is prepared from the following components in parts by weight: 90-120 parts of unsaturated polyether macromonomer, 4-6 parts of unsaturated phosphonate monomer, 7-13 parts of unsaturated carboxylic acid small monomer, 0.4-1.2 parts of initiator, 0.1-0.4 part of reducing agent, 0.3-0.6 part of chain transfer agent and alkali liquor;

the terpolymer retarder is prepared from the following components in parts by weight: 15-20 parts of unsaturated carboxylic acid small monomer, 15-20 parts of unsaturated anhydride, 25-30 parts of unsaturated ester small monomer, 0.6-1.5 parts of initiator and 0.1-0.4 part of chain transfer agent;

preferably, the organic phosphonic acid is selected from one or more of hydroxyethylidene diphosphonic acid (HEDP), aminotrimethylene phosphonic Acid (ATMP), 2-phosphonic acid-1, 2, 4-butane tricarboxylate (PBTCA), polyamino polyether methylene Phosphonic Acid (PAPEMP), 2-hydroxyphosphonoacetic acid (HPAA), ethylene diamine tetra methylene phosphonic acid (EDTMPS), and diethylenetriamine penta methylene phosphonic acid (DTPMPA).

Preferably, the inorganic phosphoric acid substances are one or a combination of more than two of sodium tripolyphosphate, sodium pyrophosphate, sodium hexametaphosphate, disodium hydrogen phosphate and sodium dihydrogen phosphate.

Preferably, the unsaturated polyether macromonomer is one or a combination of more than two of methyl allyl polyoxyethylene ether (HPEG) and isopentenyl polyoxyethylene ether (TPEG).

Preferably, the unsaturated phosphonate monomer is one or a combination of more than two of allyl diethyl phosphonate and dimethyl vinyl phosphonate; the unsaturated carboxylic acid small monomer is one or the combination of more than two of maleic anhydride, acrylic acid, methacrylic acid and itaconic acid.

Preferably, the initiator is one or a combination of more than two of ammonium persulfate, sodium persulfate, hydrogen peroxide, benzoyl peroxide or potassium persulfate.

Preferably, the reducing agent is one or a combination of more than two of vitamin C, sodium sulfite, sodium bisulfite, potassium sulfite and sodium formaldehyde sulfoxylate.

Preferably, the chain transfer agent is one or a combination of more than two of thioglycolic acid, mercaptopropionic acid, mercaptoethanol and sodium hypophosphite.

Preferably, the unsaturated ester small monomer is one or a combination of more than two of dibutyl maleate and isopropyl maleate.

The invention also provides a preparation method of the composite concrete retarder, which comprises the following steps:

(1) preparation of retarding water reducer

Dissolving 90-120 parts of polyether macromonomer in 100-120 parts of deionized water according to the proportion, stirring and dissolving into uniform and transparent solution, and adding 0.4-1.2 parts of initiator;

dissolving 7-13 parts of unsaturated carboxylic acid small monomer, 4-6 parts of unsaturated phosphonate monomer and 0.3-0.6 part of chain transfer agent in 10-13 parts of deionized water to prepare a dropping liquid A material for later use; dissolving 0.1-0.4 part of reducing agent in 18-22 parts of tap water to prepare a dropping liquid B material for later use;

at normal temperature, simultaneously adding the material A and the material B into the solution at a constant speed, wherein the dripping time is 3-3.5 hours, and after finishing the dripping, preserving the heat for 1 hour to finish the reaction;

adjusting the pH value to be neutral by using an alkali solution to obtain a transparent liquid, namely a retarding polycarboxylate superplasticizer;

(2) preparation of terpolymer retarder

Dissolving 15-20 parts of unsaturated anhydride in 25-30 parts of deionized water according to the proportion, introducing nitrogen for protection, and heating to raise the temperature to 80 ℃;

preparing a solution C from 15-20 parts of unsaturated carboxylic acid small monomer, 25-30 parts of unsaturated ester small monomer and 55-60 parts of deionized water; preparing solution D from 0.1-0.4 part of chain transfer agent and 25-30 parts of deionized water;

adding 0.6-1.5 parts of initiator into deionized water, dripping the solution C and the solution D simultaneously after 10 minutes, wherein the dripping time is 1-1.5 hours, cooling to 40 ℃ after finishing dripping, and preserving heat for 2 hours to finish reaction, wherein the obtained sample is the terpolymer retarder;

(3) the retarding water reducer, the terpolymer retarder, the organic phosphonic acid substances, the inorganic phosphoric acid substances and the saccharides are mixed to prepare the composite concrete retarder.

Compared with the prior art, the invention has the beneficial effects that: the compound concrete retarder and the preparation method thereof have the following advantages:

1. according to the invention, unsaturated phosphonate is grafted to a polycarboxylic acid water reducing agent as a functional monomer, phosphonic acid groups with a retarding effect can be gradually hydrolyzed in cement slurry, and the water reducing effect is more excellent than that of a common retarder;

2. the terpolymer prepared by the invention is a polyelectrolyte, has designability of molecular structure, and can chelate calcium ions in cement, thereby effectively delaying cement hydration and achieving a retarding effect;

3. the invention compounds the retarding polycarboxylate superplasticizer, the terpolymer, other organic and inorganic retarders and saccharides together, and achieves excellent retarding effect through the synergistic effect of the substances.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The first embodiment is as follows:

the composite concrete retarder is prepared from the following components in parts by weight: : 50 parts of a retarding water reducer, 5 parts of a terpolymer retarder, 10 parts of an organic phosphonic acid substance, 10 parts of an inorganic phosphoric acid substance, and 1 part of a saccharide substance:

the retarding water reducer is prepared from the following components in parts by weight: 90 parts of unsaturated polyether macromonomer, 4 parts of unsaturated phosphonate monomer, 7 parts of unsaturated carboxylic acid small monomer, 0.4 part of initiator, 0.1 part of reducing agent, 0.3 part of chain transfer agent and alkali liquor;

the terpolymer retarder is prepared from the following components in parts by weight: 15 parts of unsaturated carboxylic acid small monomer, 15 parts of unsaturated anhydride, 25 parts of unsaturated ester small monomer, 0.6 part of initiator and 0.1 part of chain transfer agent;

a preparation method of the compound concrete retarder comprises the following steps:

(1) preparation of retarding water reducer

Dissolving 100 parts of polyether macromonomer in 110 parts of deionized water according to a ratio, stirring and dissolving into a uniform and transparent solution, and then adding 0.5 part of initiator, wherein the polyether macromonomer is methyl allyl polyoxyethylene ether, and the initiator is hydrogen peroxide (the mass concentration is 27.5%);

dissolving 9 parts of unsaturated carboxylic acid small monomer, 5 parts of unsaturated phosphonate monomer and 0.4 part of chain transfer agent in 10 parts of deionized water to prepare a dropping liquid A material for later use; dissolving 0.1 part of reducing agent in 20 parts of tap water to prepare a dropping liquid B material for later use, wherein the unsaturated carboxylic acid small monomer is acrylic acid, the unsaturated phosphonate monomer is diethyl allylphosphate, the chain transfer agent is thioglycolic acid, and the reducing agent is vitamin C;

at normal temperature, simultaneously adding the material A and the material B into the solution at a constant speed, wherein the dripping time is 3 hours, and after finishing the dripping, preserving the heat for 1 hour to finish the reaction;

adjusting the pH value to be neutral by using an alkali solution to obtain a transparent liquid, namely a retarding polycarboxylate superplasticizer;

(2) preparation of terpolymer retarder

Dissolving 15 parts of unsaturated anhydride into 25 parts of deionized water according to a ratio, introducing nitrogen for protection, heating to raise the temperature to 80 ℃, and selecting maleic anhydride as the unsaturated anhydride;

preparing a solution C from 17 parts of unsaturated carboxylic acid small monomer, 25 parts of unsaturated ester small monomer and 56 parts of deionized water; preparing a solution D from 0.2 part of chain transfer agent and 30 parts of deionized water, wherein the unsaturated carboxylic acid small monomer is acrylic acid, the unsaturated ester small monomer is dibutyl maleate, and the chain transfer agent is sodium bisulfite;

adding 0.8 part of initiator into deionized water, dropwise adding the solution C and the solution D at the same time after 10 minutes, wherein the dropwise adding time is 1.5h, cooling to 40 ℃ after the dropwise adding is finished, and preserving heat for 2h to finish the reaction, wherein the obtained sample is the terpolymer retarder, and the initiator is ammonium persulfate;

(3) 50 parts of retarding water reducer, 5 parts of terpolymer retarder, 7 parts of hydroxyethylidene diphosphonic acid, 3 parts of ethylenediamine tetramethylene phosphonic acid, 5 parts of disodium hydrogen phosphate, 5 parts of sodium tripolyphosphate and 1 part of glucose are compounded to obtain a mixture, and the compound retarder is obtained.

Example two:

the composite concrete retarder is prepared from the following components in parts by weight: : 60 parts of a retarding water reducer, 8 parts of a terpolymer retarder, 11 parts of organic phosphonic acid substances, 12 parts of inorganic phosphoric acid substances, and 2 parts of saccharides:

the retarding water reducer is prepared from the following components in parts by weight: 110 parts of unsaturated polyether macromonomer, 5 parts of unsaturated phosphonate monomer, 10 parts of unsaturated carboxylic acid small monomer, 0.8 part of initiator, 0.3 part of reducing agent, 0.5 part of chain transfer agent and alkali liquor;

the terpolymer retarder is prepared from the following components in parts by weight: 18 parts of unsaturated carboxylic acid small monomer, 18 parts of unsaturated anhydride, 28 parts of unsaturated ester small monomer, 1.0 part of initiator and 0.2 part of chain transfer agent;

a preparation method of the compound concrete retarder comprises the following steps:

(1) preparation of retarding water reducer

Dissolving 100 parts of polyether macromonomer in 120 parts of deionized water according to a ratio, stirring and dissolving into a uniform and transparent solution, adding 1.1 parts of initiator, wherein the polyether macromonomer is isopentenyl polyoxyethylene, and the initiator is ammonium persulfate;

dissolving 11 parts of unsaturated carboxylic acid small monomer, 5 parts of unsaturated phosphonate monomer and 0.5 part of chain transfer agent in 12 parts of deionized water to prepare a dropping liquid A material for later use; dissolving 0.15 part of reducing agent in 20 parts of tap water to prepare a dropping liquid B material for later use, wherein the unsaturated carboxylic acid small monomer is acrylic acid, the unsaturated phosphonate monomer is dimethyl vinyl phosphonate, the chain transfer agent is mercaptopropionic acid, and the reducing agent is vitamin C;

at normal temperature, simultaneously adding the material A and the material B into the solution at a constant speed, wherein the dripping time is 3.5 hours, and after finishing the dripping, preserving the heat for 1 hour to finish the reaction;

adjusting the pH value to be neutral by using an alkali solution to obtain a transparent liquid, namely a retarding polycarboxylate superplasticizer;

(2) preparation of terpolymer retarder

Dissolving 18 parts of unsaturated anhydride into 28 parts of deionized water according to a proportion, introducing nitrogen for protection, heating to raise the temperature to 80 ℃, and selecting maleic anhydride as the unsaturated anhydride;

preparing 20 parts of unsaturated carboxylic acid small monomer, 25 parts of unsaturated ester small monomer and 60 parts of deionized water into a solution C; preparing a solution D from 0.3 part of chain transfer agent and 25 parts of deionized water, wherein the unsaturated carboxylic acid small monomer is acrylic acid, the unsaturated ester small monomer is isopropyl maleate, and the chain transfer agent is sodium bisulfite;

adding 1.0 part of initiator into deionized water, dropwise adding the solution C and the solution D at the same time after 10 minutes, wherein the dropwise adding time is 1.5h, cooling to 40 ℃ after the dropwise adding is finished, and preserving heat for 2h to finish the reaction, wherein the obtained sample is the terpolymer retarder, and the initiator is ammonium persulfate;

(3) 60 parts of retarding water reducer, 7 parts of terpolymer retarder, 6 parts of 2-phosphonobutane-1, 2, 4-tricarboxylic acid, 5 parts of polyamino polyether methylene Phosphonic Acid (PAPEMP), 6 parts of sodium hexametaphosphate, 5 parts of sodium citrate, 2 parts of sodium pyrophosphate and 1 part of white sugar are compounded to obtain a compound retarder.

Example three:

the composite concrete retarder is prepared from the following components in parts by weight: : 70 parts of a retarding water reducer, 10 parts of a terpolymer retarder, 12 parts of organic phosphonic acid substances, 15 parts of inorganic phosphoric acid substances, and 3 parts of saccharides:

the retarding water reducer is prepared from the following components in parts by weight: 120 parts of unsaturated polyether macromonomer, 6 parts of unsaturated phosphonate monomer, 13 parts of unsaturated carboxylic acid small monomer, 1.2 parts of initiator, 0.4 part of reducing agent, 0.6 part of chain transfer agent and alkali liquor;

the terpolymer retarder is prepared from the following components in parts by weight: 20 parts of unsaturated carboxylic acid small monomer, 20 parts of unsaturated anhydride, 30 parts of unsaturated ester small monomer, 1.5 parts of initiator and 0.4 part of chain transfer agent;

a preparation method of the compound concrete retarder comprises the following steps:

(1) preparation of retarding water reducer

Dissolving 110 parts of polyether macromonomer in 110 parts of deionized water according to a ratio, stirring and dissolving into a uniform and transparent solution, adding 0.6 part of initiator, wherein the polyether macromonomer is isopentenyl polyoxyethylene, and the initiator is hydrogen peroxide;

dissolving 10 parts of unsaturated carboxylic acid small monomer, 6 parts of unsaturated phosphonate monomer and 0.6 part of chain transfer agent in 12 parts of deionized water to prepare a dropping liquid A material for later use; dissolving 0.1 part of reducing agent in 18-22 parts of tap water to prepare a dropping liquid B material for later use, wherein the unsaturated carboxylic acid small monomer is acrylic acid, the unsaturated phosphonate monomer is dimethyl vinyl phosphonate, the chain transfer agent is mercaptopropionic acid, and the reducing agent is vitamin C;

at normal temperature, simultaneously adding the material A and the material B into the solution at a constant speed, wherein the dripping time is 3.5 hours, and after finishing the dripping, preserving the heat for 1 hour to finish the reaction;

adjusting the pH value to be neutral by using an alkali solution to obtain a transparent liquid, namely a retarding polycarboxylate superplasticizer;

(2) preparation of terpolymer retarder

Dissolving 15 parts of unsaturated anhydride into 25 parts of deionized water according to a ratio, introducing nitrogen for protection, heating to raise the temperature to 80 ℃, and selecting maleic anhydride as the unsaturated anhydride;

preparing a solution C from 15 parts of unsaturated carboxylic acid small monomer, 25 parts of unsaturated ester small monomer and 55 parts of deionized water; preparing a solution D from 0.3 part of chain transfer agent and 27 parts of deionized water, wherein the unsaturated carboxylic acid small monomer is acrylic acid, the unsaturated ester small monomer is isopropyl maleate, and the chain transfer agent is sodium bisulfite;

adding 1.1 parts of initiator into deionized water, dropwise adding the solution C and the solution D at the same time after 10 minutes, wherein the dropwise adding time is 1.5h, cooling to 40 ℃ after the dropwise adding is finished, and preserving heat for 2h to finish the reaction, wherein the obtained sample is the terpolymer retarder, and the initiator is ammonium persulfate;

(3) 50 parts of retarding water reducer, 10 parts of terpolymer retarder, 5 parts of aminotrimethylene phosphonic acid, 5 parts of polyamino polyether methylene Phosphonic Acid (PAPEMP), 6 parts of sodium hexametaphosphate, 5 parts of sodium pyrophosphate and 1 part of glucose are compounded to obtain a mixture, namely the compound retarder.

The concrete performance tests of the samples synthesized in the examples 1, 2 and 3 and the commercial retarder are compared, and the conch P.O 42.5.5 cement, the II-grade fly ash, the machine-made sand with the fineness modulus of 2.60, the crushed stone with the particle size of 5-30mm, the mixing amount of the retarder of 0.3wt percent and the experimental temperature of 35 ℃ are adopted. Concrete performance tests were performed according to the concrete mix ratios of table 1. The initial setting time and the final setting time are carried out according to GB/T50080-2016 Standard test method for the Performance of common concrete mixtures; the concrete compressive strength is carried out according to GB/T50081 and 2019 Standard test method for physical and mechanical properties of concrete.

Table 1: mixing ratio (kg cm) of C50 concrete test^-3)

Table 2: setting time and compressive strength of concrete at 35 ℃

As can be seen from Table 1, the composite concrete retarder disclosed in the embodiment of the invention has better retarding effect and no loss of later-stage compressive strength compared with the comparative example, which is the result of the synergistic effect of the components.

The above description is only an embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes, which are made by the present specification, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.