Preparation method of concrete slump retaining agent

Abstract

The invention belongs to the field of cement additives and particularly relates to a preparation method of concrete slump retaining agent. The method includes the steps of firstly, adding straw hydrolyzed sugar into chemical oxidant, and feeding air for reaction; secondly, at normal temperature, adding chemical oxidant C, dropwise adding lye to allow system pH to be 7-8, and allowing for reaction; thirdly, adding noble metal catalyst, and dropwise adding lye to allow system pH to be 8-8.5 to obtain the concrete slump retaining agent; wherein the chemical oxidant includes chemical oxidant A and chemical oxidant B; the weight ratio of the straw hydrolyzed sugar, the chemical oxidant A and the chemical oxidant B is 800-1200:2-30:1-8; reaction temperature is 30-80 DEG C; and reaction time is 1-3 hours. The preparation method is good in product quality, low in cost, low in catalyst consumption, and stable in reaction.

Description

technical field [0001] The invention belongs to the field of cement additives, in particular to a preparation method of a concrete slump retaining agent. Background technique [0002] Slump retaining agent is an admixture that can keep the slump of concrete from losing rapidly. The slump-preserving agent is essentially a setting retarder, which delays the hydration and setting of cement to maintain the slump. Ordinary superplasticizers such as wood calcium or wood sodium and polycarboxylate superplasticizers have a retarding effect, and generally have a better slump-preserving effect. For naphthalene-based high-efficiency water reducers, it is often necessary to compound slump-preserving components, or to add them twice on site, otherwise the slump will lose quickly and construction will be difficult. If the ambient temperature is high and the concrete transportation distance is relatively long, the slump retaining agent or retarder should be used, which can achieve good r...

AI Technical Summary

Problems solved by technology

Among the industrialized production methods, more than 80% use noble metal catalyzed heterogeneous oxidation method. Although this method has simple process, stable reaction, easy control, mild reaction conditions and high conversion rate (98%); but there are also great problems , which is manifested in the fact that the catalytic rate decreases after the catalyst is recycled for a certain number of times. The catalyst is easily poisoned and deactivated during use, which greatly increases the production cost. Generally, the amount of catalyst used is 1-2% of the sugar mass. How to reduce the amount of catalyst becomes the problem. The most important research directions in the field