Over the past decade, the synthesis technology for polycarboxylic superplasticizer mother liquids has matured through several iterations. The process has evolved from using purified water to tap water, from high-temperature to low-temperature ambient conditions, and from a two-step method to a one-step method, lowering the barrier to entry for mother liquid synthesis. Consequently, mother liquids on the market now exhibit similar performance characteristics and severe homogenization in concrete.

The raw materials for compounding functional polycarboxylic superplasticizer additives can be broadly categorized as follows: polycarboxylic superplasticizer concentrate, workability modifiers, retarders, air-entraining agents, defoamers, water-retention agents, anti-freeze agents, and earlyaccelerator. Simultaneously, the variety of individual raw materials is complex and diverse. Today, we focus specifically on how to select and use slump-resistant polycarboxylic superplasticizer mother liquids.

Among the diverse range of polycarboxylate-based mother liquids, the most widely applied types can be categorized as high-water-reducing mother liquids and high-slump-resistant mother liquids. In the market, some commonly refer to slump-resistant mother liquids as “slump-resistant agents.” Although their functionality differs significantly from water-reducing mother liquids, their synthesis processes are nearly identical, differing only in the raw materials used. Therefore, classifying slump-resistant mother liquids under blended functional raw materials is more standardized.

Many customers hear claims like “My water-reducing mother liquid is comprehensive, offering both slump retention and high water-reduction effects in concrete.” These statements are essentially sales pitches used by representatives to promote their products. Polycarboxylic superplasticizers, as third-generation admixtures, indeed own superior slump retention and higher water-reduction performance compared to second-generation admixtures like naphthalene-based superplasticizers. These differences stem from generational variations and the disparity in comparison benchmarks. During chemical synthesis, achieving both high water-reduction rates and high slump-resistant performance in polycarboxylic superplasticizer mother liquid is inherently contradictory. While adjusting the acid/ether ratio between acrylic acid and monomer can boost water-reduction rates, it simultaneously compromises slump retention. Amidst the trade-off between enhancing water-reduction rate for cost-effectiveness versus improving slump retention for application reliability, the performance of water-reducing mother liquids on the market is largely comparable. Conversely, slump-resistant water-reducing superplasticizers exhibit significantly greater variability in slump retention performance.

To achieve better slump-resistant properties, the synthesis process of slump-resistant mother liquors can be adjusted through the following measures:

1. Replace HPEG with TPEG as the monomer;
2. Substitute part of the acrylic acid with hydroxyethyl acrylate;
3. Control the acid-ether ratio.

It is recommended to use a slow-release slump-resistant mother liquid without water-reducing effects in concrete. This allows for easy adjustment of the ratio between water-reducing mother liquid and slump-resistant mother liquid during compounding, facilitating better control over concrete slump retention duration. Using slump-resistant mother liquid inherently increases costs. The higher the concrete’s slump-resistant requirements and the longer the desired retention time, the greater the dosage of slump-resistant mother liquid needed. Generally, while ensuring normal concrete construction, minimize the dosage of slump-resistant mother liquid to reduce costs.

We recommend the following products:

High-Water-Reducing Mother Liquid: 156L

High-Slump-Resistant Mother Liquid: 157L

These two products can meet the performance requirements for most ready-mix concrete production and construction applications.