Chloride-free and low-alkaline powder accelerator

A technology of quick-setting agent and alkali type, which is applied in the field of concrete additives, can solve the problems of reducing final strength, water-tightness, freeze-thaw resistance, and concrete durability, and achieves the effects of improving cost performance, improving performance and reducing costs.

Inactive Publication Date: 2013-03-20
HENAN POLYTECHNIC UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

It will also have adverse effects on shotcrete, which will more or less reduce its ultimate strength, water tightness, and freeze-thaw resistance, thereby reducing the durability of concrete

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] Chlorine-free and low-alkali shotcrete quick-setting agent is formulated with 2.0% aluminum sulfate (based on the mass percentage of cement, the same below) and 1.5% sodium fluoride, and the two are mixed into the cement at the same time according to the above-mentioned cement mass percentage. The initial setting time of the cement slurry with a water-cement ratio of 0.4 is 3 minutes, and the final setting time is 5 minutes. The mass ratio of cement to standard sand is 1:1.5, and the compressive strength of cement mortar with a water-cement ratio of 0.5 is 1d. 14.34MPa, 28d compressive strength ratio exceeds 93%.

Embodiment 2

[0024] Chlorine-free and low-alkali shotcrete quick-setting agent is formulated with aluminum sulfate 2.0% and sodium metaaluminate 0.75%. The cement is mixed with the two-component quick-setting agent at the same time, which can make the cement paste with a water-cement ratio of 0.4 The initial setting time is 3.5 minutes, and the final setting time is 6 minutes. The mass ratio of cement and standard sand is 1:1.5, and the cement mortar with a water-cement ratio of 0.5 can achieve a compressive strength of 7.42 MPa in 1 day and a compressive strength ratio of over 90 in 28 days. %.

Embodiment 3

[0026] Chlorine-free and low-alkali shotcrete accelerator is formulated with aluminum sulfate 2.0%, sodium metaaluminate 0.25%, and sodium fluoride 0.25%. The initial setting time of 0.4 cement slurry is 2.5 minutes, and the final setting time is 4.5 minutes. The mass ratio of cement and standard sand can be 1:1.5, and the compressive strength of cement mortar with a water-cement ratio of 0.5 can reach 8.28MPa in 1 day. The 28d compressive strength ratio exceeds 95%.

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Abstract

The invention discloses a chloride-free and low-alkaline powder accelerator and application thereof. The powder accelerator comprises aluminum sulfate and sodium metaaluminate and / or sodium fluoride, and the low-alkaline type refers to that the accelerator does not contain additional alkaline. The compound accelerator integrates the advantages of good accelerated setting effect of an alkaline-containing accelerator and strength loss prevention of an alkaline-free accelerator, meanwhile, the preparation cost is reduced, and the cost performance is improved. Therefore, the low-alkaline efficient accelerator is prepared, and the harm of the accelerator to the human body is reduced at the same time. The accelerator is suitable for sprayed concrete requiring accelerated setting; and by using the compound accelerator, the performance of cement concrete is improved, the solidification time of the cement concrete is regulated, the later strength of the cement concrete is not affected, and the production cost is reduced.

Description

technical field [0001] The patent of the present invention relates to a concrete additive, in particular to a chlorine-free and low-alkali powder accelerator and its application. Background technique [0002] Cement accelerator (referred to as accelerator), also known as accelerator, is a chemical admixture that can promote the rapid setting of cement or concrete. It can significantly shorten the time required for concrete to change from slurry to solid, within a few minutes. It can make it lose its fluidity and harden, and it can reach final setting in ten minutes, with high early strength. Accelerator as a chemical product, its production and use can be traced back to the 1930s [1] . The birth and use of accelerators made shotcrete construction possible, and played an important role in the establishment of shaft shotcrete support technology. [0003] With the wide application and rapid development of shotcrete technology in geotechnical engineering, people began to pay ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B22/14C04B103/12
Inventor 王雨利杨雷罗树琼刘小星刘素霞
Owner HENAN POLYTECHNIC UNIV
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