A kind of composite concrete admixture and its preparation method and use

A concrete admixture and composite technology, which is applied in the field of cement products and concrete, can solve the problems of construction quality defects, waste, waste concrete, etc., and achieve good economic benefits, reduced solid content, and short setting time.

Active Publication Date: 2021-12-03
中铁五局集团华南工程有限责任公司 +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, this method requires the on-site technicians to have rich experience. If you are not careful, you will add too much water-reducing agent, which will cause serious segregation, bleeding or laitance of the concrete, causing serious quality defects to the construction, or discarding the concrete, causing serious waste.
Therefore, the practice of adding ordinary polycarboxylate superplasticizers at the end cannot solve the fundamental problem
[0006] (2) Since the amount of water-reducing agent added after the site cannot be determined through experiments in advance, it cannot effectively solve the problem of insufficient retention time of concrete workability. People have invented slow-release polycarboxylate water-reducer
How to rationally compound and use these retarders to form a new retarding technology and use it to delay cement hydration and ensure that the cement hydration speed matches the release speed of slow-release polycarboxylate superplasticizers is insufficient to solve these problems

Method used

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  • A kind of composite concrete admixture and its preparation method and use
  • A kind of composite concrete admixture and its preparation method and use
  • A kind of composite concrete admixture and its preparation method and use

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0029] Weigh 6 parts of polycarboxylate superplasticizer and 8 parts of slow-release polycarboxylate superplasticizer according to the proportion, mix them evenly, add water to dilute at a ratio of 1:5, and then add 3 parts of sodium gluconate, 0.5 parts of sucrose, 0.5 parts of sodium hexametaphosphate, mixed and stirred evenly, the temperature of the solution during the preparation process does not exceed 35°C, and finally forms a composite concrete admixture, the dosage is 0.95% of the total amount of cementitious materials, and the water-binder ratio is 0.43. out the concrete.

[0030] The performance results of the concrete mixed with the composite concrete admixture in Example 1 are shown in Table 1:

[0031] Table 1 adopts the concrete test result that the compound type admixture of embodiment 1 is mixed

[0032]

[0033]For the concrete in Example 1, the slump is kept within the range of 180mm to 210mm within 2.5 hours after the self-mixing machine, the expansion i...

Embodiment 2

[0035] Weigh 6.5 parts of polycarboxylate superplasticizer and 8 parts of slow-release polycarboxylate superplasticizer according to the proportion, mix them evenly, add water to dilute at a ratio of 1:6, and then add 2 parts of sodium gluconate, 1.5 parts of sucrose, 0.5 parts of sodium hexametaphosphate, 0.5 parts of sodium citrate, mixed and stirred evenly, the temperature of the solution during the preparation process does not exceed 35 ° C, and finally a composite concrete admixture is formed. The dosage is 0.9% of the total amount of cementitious materials, and 0.43 The water-binder ratio is mixed to produce concrete.

[0036] The performance results of the concrete mixed with the composite concrete admixture in Example 2 are shown in Table 2:

[0037] The concrete test result that table 2 adopts the composite type admixture of embodiment 2 to mix

[0038]

[0039] For the concrete in Example 2, the slump is maintained within the range of 180mm to 220mm within 2.5 ho...

Embodiment 3

[0041] Weigh 5.5 parts of polycarboxylate superplasticizer and 13.3 parts of slow-release polycarboxylate superplasticizer according to the ratio, mix and stir evenly, add water to dilute at a ratio of 1:7, then add 2.5 parts of sodium gluconate and 1 part of sucrose , 0.5 parts of sodium dihydrogen phosphate, 0.5 parts of tartaric acid, mixed and stirred evenly, the temperature of the solution during the configuration process does not exceed 35 ° C, and finally a composite concrete admixture is formed. The dosage is 1.0% of the total amount of cementitious materials, and 0.43 Water-binder ratio mixes concrete.

[0042] The performance results of the concrete mixed with the composite concrete admixture in Example 3 are shown in Table 3:

[0043] Table 3 adopts the concrete test result that the compound type admixture of embodiment 3 is mixed

[0044]

[0045]

[0046] For the concrete in Example 3, within 4.5 hours after the concrete was mixed out of the machine, the sl...

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Abstract

The invention relates to a composite concrete admixture, which comprises: 5-8 parts of polycarboxylate water-reducer, 6-14 parts of slow-release polycarboxylate water-reducer, 3 parts by weight of saccharide retarder ~4.5 parts, organic acid retarder 0~0.5 part, inorganic acid retarder 0.5~1 part. Retarders of the present invention include sugar retarders, organic acid retarders and inorganic acid retarders, and their effect is to inhibit cement hydration in the early stage, slow down the hydration rate of cement, and reduce the impact on concrete. The consumption rate of water reduces the dosage of the slow-release superplasticizer, so that the release rate of the slow-release superplasticizer matches the cement hydration speed. The effects of each retarder are different, neither significantly delaying the setting time of concrete, but also inhibiting cement hydration in the early stage.

Description

technical field [0001] The invention relates to the field of concrete and cement products, in particular to a composite concrete admixture and its preparation method and application. Background technique [0002] Concrete is the main material of modern construction projects. The amount of concrete poured in our country reaches billions of cubic meters every year. Such a large production volume makes centralized mixing of concrete its main production method. The transportation and pouring process of concrete after intensive mixing takes a period of time, usually more than 1 hour or even longer, and the maintenance of the workability of the concrete mixture during this period will have a significant impact on the efficacy and quality of concrete pouring. Serious impact. If the maintenance time is insufficient, it will make the construction pouring on site unsustainable, cause construction interruption, seriously affect the construction effect, and also cause on-site water add...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C04B24/32C04B28/00
CPCC04B28/00C04B40/0039C04B2103/302C04B2201/50C04B24/06C04B24/10C04B24/32C04B22/16
Inventor 朱永清李瑞青陈跃龙邹琳郑宾杨阳田坤
Owner 中铁五局集团华南工程有限责任公司
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