CHEMFIX VMA-107
Viscosity Modifying Admixture for Concrete
CHEMFIX VMA is a high-performance Viscosity Modifying Admixture (VMA) specially designed to improve the stability, cohesion and rheological properties of fresh concrete. It helps control segregation and bleeding while maintaining the required flowability and workability of concrete.
CHEMFIX VMA is particularly suitable for Self-Compacting Concrete (SCC), high-flow concrete, pumped concrete, high-performance concrete and concrete mixes containing high-range water-reducing admixtures such as PCE.
Developed with reference to EN 934-2, EFNARC/EFCA Guidelines for VMA, and relevant ASTM C494/C494M test methods, as applicable.
Key Advantages:
1. Excellent Segregation Control
CHEMFIX VMA increases the cohesion of the concrete mix and helps prevent coarse aggregate from separating from the cement paste.
2. Reduces Bleeding
It helps reduce excessive water migration to the concrete surface, contributing to a more stable and uniform concrete mixture.
3. Improves SCC Stability
In Self-Compacting Concrete, CHEMFIX VMA helps maintain a balance between high flowability and mixture stability, allowing the concrete to flow without excessive segregation.
4. Enhances Cohesion
The admixture improves the internal cohesion of fresh concrete, particularly in mixes with low fines content or high water-reducing admixture dosage.
5. Supports Pumpability
By improving mixture stability and cohesion, CHEMFIX VMA can help maintain a more consistent concrete mix during pumping.
6. Improves Surface Quality
Better concrete stability and uniformity can help reduce surface defects such as segregation-related voids and uneven finishing.
7. Compatible with High-Range Water Reducers
8. Helps Optimize Concrete Mix Design
It provides greater flexibility in designing concrete mixes where workability, flowability and segregation resistance need to be carefully balanced.
- Applications / Uses:
CHEMFIX VMA is recommended for concrete applications where improved viscosity, cohesion, stability and segregation resistance are required.
– Self-Compacting Concrete (SCC)
– High-flow and high-performance concrete
– Pumped concrete
– Ready-mix concrete
– Precast concrete
– Concrete with low fines content
– PCE-based concrete mixes
– Concrete used in heavily reinforced structural sections
– Applications requiring improved resistance to segregation and bleeding
– Selected underwater concrete applications, subject to proper mix design and testing
How CHEMFIX VMA Works
When a high-range water reducer such as PCE is used, concrete can become highly fluid. Excessive fluidity may sometimes increase the risk of segregation and bleeding, particularly when the mix does not contain sufficient fines or has an unsuitable aggregate grading.
CHEMFIX VMA increases the viscosity and cohesion of the cementitious phase, helping keep the aggregate and paste uniformly distributed throughout the fresh concrete.
In simple terms:
PCE → Improves Flowability
CHEMFIX VMA → Improves Stability & Cohesion
The combined use of a suitable PCE superplasticizer and VMA can help produce concrete that is highly flowable yet stable and resistant to segregation.
Application Method
Step 1 – Prepare the Concrete/Mortar Mix
Prepare cement, sand and aggregate according to the required mix design.
Step 2 – Dilute/Add CHEMFIX C30
CHEMFIX C30 should preferably be diluted with a portion of the required mixing water or added according to the recommended site procedure.
Step 3 – Mix Thoroughly
Ensure adequate mixing so that the admixture is distributed uniformly throughout the concrete or mortar.
Step 4 – Place & Compact
Place the concrete or mortar properly and ensure adequate compaction to minimize voids and honeycombing.
Step 5 – Proper Curing
Proper curing is essential to achieve the desired strength and durability of concrete.
«Important: The optimum dosage should be established through trial mixes based on cement type, concrete grade, required workability and site conditions.»
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Compatibility
CHEMFIX VMA is designed for use with commonly used cementitious materials, aggregates and concrete admixtures.
It is particularly suitable for use with PCE-based high-range water-reducing/superplasticizing admixtures.
For optimum performance, compatibility should be verified through laboratory or site trials when used with a new cement, supplementary cementitious material or admixture combination.
Important: Do not mix CHEMFIX VMA directly with concentrated PCE or other admixtures unless the compatibility and addition sequence have been established. Follow the recommended mixing procedure and dosage determined through trial batching.
Precautions
– For professional construction use only.
– Use the recommended dosage and do not overdose.
– Excessive dosage may increase viscosity and can adversely affect concrete flowability and finishing.
– Conduct a trial mix before large-scale application.
– The optimum dosage depends on cement type, aggregate grading, water-cementitious ratio, PCE dosage and other mix constituents.
– Avoid direct contact with eyes and prolonged contact with skin.
– Wear suitable gloves, protective clothing and eye protection during handling.
– In case of eye or skin contact, rinse thoroughly with clean water and seek medical attention if irritation persists.
– Keep out of reach of children.
– Refer to the Safety Data Sheet (SDS) for detailed safety and handling information.
Packaging
CHEMFIX VMA is available in suitable packaging options for construction projects and site requirements.
Available Packaging:
5KG• 10 KG • 20 KG •220 KG • Bulk Packaging
Packaging availability may vary. Please contact CHEMFIX for current pack sizes.
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Storage
Store in a cool, dry and shaded place, away from direct sunlight and extreme temperatures.
– Keep the container tightly closed when not in use.
– Protect from contamination.
– Do not allow the product to freeze.
– Store in the original container.
– Follow the recommended storage conditions mentioned in the product TDS/SDS.
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