Secondary ettringite type expanding agent and preparation method and application thereof

A technology of secondary calcium and expansion agent, which is applied in the fields of material science and engineering science, can solve the problems of high production cost of expansion agent, complicated production process, and consumption of natural resources, so as to improve the internal stress state, protect the ecological environment, and reduce shrinkage crack effect

Active Publication Date: 2013-07-03
HOHAI UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the currently used calcium sulfoaluminate expansion agent is produced by high-temperature treatment using pure raw materials such as alum and gypsum. Not only is the production process complicated, but it also consumes a large amount of natural resources, which increases the production cost of the expansion agent.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

preparation example Construction

[0022] The specific preparation method is: (1) will contain Al 2 O 3 After mixing the volcanic ash material with calcareous material, gypsum and water, it is formed into a green body or into a ball, natural curing for 1-28 days, and dry heat curing at 80℃~90℃ for 0.5~10 hours in the curing cellar. Dehydrate and decompose the ettringite at a constant temperature of 100℃~170℃ for 0.5~10 hours, or the formed body or pellets will be autoclaved at 120℃~190℃ after 2~10 hours of static rest. ~10 hours, and then dehydrated at above 100℃ for 0.5~10 hours, or dehydrated hydrothermally synthesized aluminosilicate material and its waste at above 100℃ for 0.5~10 hours; (2) 60~95 parts by weight The above-mentioned materials are weighed with 5-40 parts by weight of anhydrous gypsum, and then mixed or ground to a particle size ≤80μm, and then sent to an air mixer for homogenization to obtain a specific surface area greater than 200m 2 / kg of powder is the secondary ettringite type expansion a...

Embodiment 1

[0026] Example 1: Preparation method of secondary ettringite type expansion agent

[0027] The following are all parts by weight

[0028] (1) Weigh 20 parts of fly ash, 5 parts of lime, 1 part of gypsum, and 12 parts of water and mix them to form a green body or pellets. Naturally cure for 1 to 28 days, and in the curing cellar at 80℃~ Dry heat curing at 90°C for 0.5-10 hours, heating to 100°C-170°C, and constant temperature for 0.5-10 hours, for dehydration and ettringite decomposition reaction. Then weigh 60 parts of the above-mentioned materials and 40 parts of anhydrous gypsum, mix and grind them and send them to an air mixer for homogenization. The obtained powder with a particle size of ≤80μm is the secondary ettringite type expansion agent.

[0029] (2) Weigh 20 parts of coal gangue, 5 parts of lime, 1 part of gypsum and 12 parts of water. After mixing and stirring, form a green body or ball, natural curing for 0-28 days, in the curing cellar at 80℃~90 Dry heat curing at ℃ ...

Embodiment 2

[0037] Example 2: Application examples of secondary ettringite type expansion agent

[0038] (1) Application of the expansion agent of the present invention in self-leveling mortar

[0039] In this embodiment, the cement is P·II 52.5; the fine sand has a fineness modulus of 1.9; the thickener is hydroxyethyl cellulose ether; the water reducing agent is aliphatic from Yancheng Jianke Concrete Admixture Technology Co., Ltd. Water reducing agent; expansion agent is the secondary ettringite type expansion agent provided by the present invention.

[0040] Adopting 1:1.5 lime-sand ratio, 1:2.5 water-cement ratio, the mixing amount of water reducing agent is 0.6% of cement mass, and the mixing amount of thickening agent is 0.3‰ of cement mass. The dry powdery secondary alum of the present invention The stone-type expansion agent is mixed (internally) with 6% equivalent cement quality. The properties of the freshly mixed self-leveling mortar are as follows: the self-expanding fluidity ...

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Abstract

The invention discloses a secondary ettringite type expanding agent and a preparation method and application thereof. The preparation method comprises the following steps of: stirring a pozzolanic material, a calcium material, plaster and water, forming into a blank or spheres, naturally curing, performing dry heating curing in a curing cell for 0.5 to 10 hours, raising the temperature to 100-170DEG C, and keeping the temperature for 0.5 to 10 hours for dehydration and ettringite decomposition reaction, or standing the formed blank or spheres for 2 to 10 hours, curing under steam pressure, and dehydrating for 0.5 to 10 hours, or dehydrating the thermally synthesized aluminosilicate material and wastes thereof at the temperature of higher than 100DEG C for 0.5 to 10 hours; and mixing and grinding 60 to 95 weight parts of material and 5 to 40 weight parts of anhydrous gypsum, or respectively grinding 60 to 95 weight parts of material and 5 to 40 weight parts of anhydrous gypsum and uniformly mixing to obtain powder of which the specific surface area is more than 200m<2> / kg, namely the secondary ettringite type expanding agent. The secondary ettringite type expanding agent can endow mortar and concrete with micro-expansion property, and improve the volume stability of the mortar and concrete.

Description

technical field [0001] The invention belongs to the technical field of material science and engineering science, and in particular relates to the preparation and application method of a secondary ettringite type expansion agent. Background technique [0002] A major defect of ordinary cement concrete products is volume shrinkage due to water loss and changes in temperature and humidity in the initial stage of setting and hardening. When the tensile stress generated by the restricted shrinkage exceeds the tensile strength of the concrete itself, the cement concrete members are prone to cracking. After cracking, the bearing capacity of the concrete decreases sharply. In addition, the durability of the concrete will be further deteriorated due to the infiltration of water, which will lead to corrosion of steel bars, structural damage, and reduce the performance of the concrete. The shrinkage and cracking of concrete has become an extremely common and serious problem in enginee...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C04B22/14
CPCC04B40/0039Y02W30/91C04B7/323C04B20/0076C04B22/143C04B7/12C04B18/0445C04B18/08C04B18/12C04B22/064C04B18/027C04B18/16
Inventor 蒋亚清胡飞龙顾越陈龙刘小艳
Owner HOHAI UNIV
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