Welan Gum is a fermentation-derived heteropolysaccharide used as a high-efficiency rheology modifier and viscosity modifying admixture (VMA) in self-compacting concrete. In SCC systems, it helps control plastic viscosity and yield stress so that the mix remains highly flowable while keeping coarse aggregates uniformly suspended.​

When combined with high-range water reducers, Welan Gum allows SCC to achieve high deformability, high flowability and high passing ability without segregation or excessive bleeding. This makes it a valuable component for robust and stable SCC mixes in both precast and cast-in-place applications。

Welan Gum improves the cohesiveness of highly fluid mixes, helping to prevent coarse aggregate settlement and surface bleeding in SCC, even at high slump-flow values.

By stabilizing the cement paste and fine particles, Welan Gum helps SCC flow through congested reinforcement while producing dense, smooth and defect-minimized surfaces for precast and cast-in-place elements.

SCC containing Welan Gum maintains more stable viscosity and slump flow during transport, placing and finishing, contributing to improved robustness against variations in materials and temperature.

Welan Gum functions effectively at low dosages typical for VMAs, giving strong improvements in segregation resistance and washout resistance when used with suitable superplasticizers.

Welan Gum is compatible with a wide range of supplementary cementitious materials and commonly used high-range water reducers, allowing flexible SCC mix design tailored to local materials.

 Precast SCC elements
Used in precast beams, slabs, walls, pipes and other factory-produced components where high flowability, excellent surface finish and dimensional accuracy are required.

The optimum Welan Gum dosage depends on the mix design, target rheology and application conditions, and should always be established through laboratory and field trials. In SCC, Welan Gum is typically used at low dosage levels relative to the cement content, in the range common for viscosity modifying admixtures, to enhance stability and robustness.

• First adjust the dosage of high-range water reducer to reach the target slump-flow and deformability for SCC.​
• Then fine-tune the Welan Gum dosage to achieve the required viscosity, segregation resistance and passing ability, while maintaining the desired flow.

• First adjust the dosage of high-range water reducer to reach the target slump-flow and deformability for SCC.​
• Then fine-tune the Welan Gum dosage to achieve the required viscosity, segregation resistance and passing ability, while maintaining the desired flow.

Welan Gum belongs to the family of polysaccharide-based viscosity modifying admixtures, which also includes xanthan gum and similar biopolymers. Compared with some conventional cellulose-ether-based VMAs, Welan Gum can deliver strong rheology control and washout resistance at low dosages while maintaining high flowability in cement systems.​

In SCC, Welan Gum is often used together with or as an alternative to cellulose ethers and other gum-type VMAs to fine-tune plastic viscosity, segregation resistance and surface appearance. By adjusting the combination of Welan Gum and superplasticizer, robust SCC mixes can be developed for different aggregates, cement types and environmental conditions.

Unionchem focuses on supplying high-quality Welan Gum and related rheology modifiers for the construction and building materials industry, including self-compacting concrete applications. Welan Gum from Unionchem is produced with consistent quality, supported by technical data sheets (TDS), certificates of analysis (COA) and stable batch-to-batch performance.​

Unionchem provides technical support to help SCC producers, precast plants and ready-mix suppliers select suitable Welan Gum grades and trial dosage ranges based on their raw materials and target performance. Flexible packing and shipping options are available to serve customers worldwide.