Super-long super slow release type polycarboxylic acid slump-retaining agent master batch

Abstract

The invention discloses a super-long super slow release type polycarboxylic acid slump-retaining agent master batch suitable for projects such as hydraulic tunnels, railway tunnels, metros and underground oil and gas delivery adopting concrete having the capability of retaining slump for 4-6 hours under the conditions of hot weather and long distance. Limited by 40% of the mass percent of mother liquid, the total mass of synthesized raw materials is 1000 parts, the usage amount proportion is that the usage amount of polyether macromonomer accounts for 325-335 parts, the usage amount of unsaturated carboxylic acid micro-monomer accounts for 10.0-18.0 parts, the usage amount of acrylic hydroxyalkanoate accounts for 35.0-45.0 parts, the usage amount of crosslinking monomer accounts for 5.0-10.0 parts, the usage amount of sulfonic acid type chain transfer agent accounts for 2.0-5.0 parts, the usage amount of hydrogen peroxide accounts for 2.0-3.5 parts, the usage amount of vitamin C accounts for 0.60-0.90 part, the usage amount of caustic soda liquid accounts for 7-10 parts, and the balance is water. The polycarboxylic acid slump-retaining agent is moderate in molecular weight, can be independently used or compounded with other polycarboxylic acid water reducing agents for usage, can remarkably improve the indexes such as slump-retaining property, cohesiveness and flowing retention ability of newly mixed concrete in 6 hours.

Description

technical field [0001] The invention relates to the technical field of admixtures for cement-based cementitious materials, in particular to an ultra-long and ultra-slow-release polycarboxylate slump-retaining agent masterbatch, which is suitable for long-term transportation that will cause excessive loss of concrete slump Large hydraulic tunnels, railway tunnels, subways, underground oil and gas transmission and storage projects. Background technique [0002] With the rapid development of my country's economy and the improvement of construction level, the problem of slump loss of fresh concrete has always been a difficult problem in engineering construction, especially the long-term transportation will lead to excessive loss of concrete slump, which will affect the work of concrete sex. Especially with the excavation and construction of ultra-long tunnels, the engineering community has higher and higher requirements for the slump and fluidity of wet shotcrete used in tunnels...

AI Technical Summary

Problems solved by technology

[0002] With the rapid development of my country's economy and the improvement of construction level, the problem of slump loss of fresh concrete has always been a difficult problem in engineering construction, especially the long-term transportation will lead to excessive loss of concrete slump, which will affect the work of concrete sex

The retarder cannot effectively improve the slump retention ability of the polycarboxylate superplasticizer, and it is easy to cause the setting time to be too long and reduce the early strength; for the slump retention agent with excellent performance in general engineering, the slump retention time of concrete under hot conditions Still hard to exceed 2h

The reason is that the existing retarders or slump-retaining agents cannot significantly increase the dosage of slow-release polycarboxylate superplasticizers in concrete at one time. Once the dosage is too high, it is easy to cause segregation and bleeding in the initial working state of the concrete , or due to the strong slow-release effect at a specific time point, segregation and bleeding occur during the application of concrete, which makes the state of the concrete uncontrollable and difficult to construct