Amino sulfonic acid water reducing agent with very low alkali content and production process thereof

Abstract

Ultra-low-alkali sulfamic acid-based water reducer, 1) After mixing the aminoaryl sulfonating agent, phenolic monomer and water, adjust the pH value of the reaction system to 7-9.5 with an alkaline regulator, drop Add a condensing agent, heat up to 50-100°C and react for 0.5-2h; 2) Adjust the pH value of the system to 8-11 with an alkaline regulator, add a compound containing an amide group, and react at 70-100°C for 2 -10h; 3) Adjust the pH value of the system to 8.5-13 with an alkaline regulator, react at 85-100°C for 0.5-3.0h, cool down and discharge, and then spray dry. The dosage of each raw material is: aminoaryl sulfonating agent: 10.5-32%, phenolic monomer: 3.2-16%, compound containing amide group 0-10.5%, condensing agent: 9.5-61.0%, basic regulator : 0.7-11.5%, water: 17.5-65%. The outstanding feature of the present invention is that the total alkali content is less than 1.0%, or even zero.

Description

Technical field: [0001] The invention relates to an ultra-low-alkali sulfamate-based water reducer with a total alkali content of less than 1 percent and a manufacturing process thereof, which belongs to the technical field of building materials. Background technique: [0002] Alkali-Aggregate Reaction (AAR) is the reaction between cement, admixture, mixture and alkali (Na 2 O or K 2 O) It reacts with the active components in the aggregate, and gradually reacts several years after the concrete is poured (several years to twenty or thirty years). The reaction product absorbs water and expands to cause internal stress in the concrete, expands and cracks, and causes the concrete to lose its design performance. . Because the active aggregate is generally uniformly distributed after stirring. Therefore, once the alkali-aggregate reaction occurs, all parts of the concrete will generate expansion stress, and the concrete itself will swell and crack, and if it develops seriously,...

AI Technical Summary

Problems solved by technology

[0004] Since the alkali-aggregate reaction must have sufficient alkali content, sufficient amount of active aggregate and sufficient water supply in the concrete, the three conditions exist at the same time, and it is not required to limit the concrete in any case. However, it promotes the formation and development of shrinkage cracks in concrete and causes the deterioration of concrete structures and affects the durability of concrete. However, high alkali content is a greater threat to concrete.

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