Concrete additives & specialty materials
Concrete additives & specialty materials
Magnesium Oxide (MgO) Shrinkage Reducing Admixture
Magnesium Oxide (MgO) Shrinkage Reducing Admixture is a high-performance concrete expansive agent utilizing adjustable activity of lightly calcined MgO to precisely match the released expansion energy and timing with the shrinkage of concrete structures, generating post-pour crystals for effective compensation, micro-expansion or zero-shrinkage states, and crack-free durability in waterproof and large-scale projects. Post-Pour Expansion Crystals Zero-Shrinkage Compensation Crack Prevention Durability Waterproof Structure Integrity
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Product overview
Performance and application overview.
Magnesium Oxide (MgO) Shrinkage Reducing Admixture is a high-performance concrete admixture designed primarily around post-pour temperature dynamics. It generates expansion crystals through specialized chemical reactions at various stages after pouring, effectively compensating for concrete shrinkage to achieve micro-expansion or zero-shrinkage states. This targeted MgO expansive admixture resolves cracking issues caused by shrinkage, enhancing durability and structural integrity in waterproof and large-scale applications.
Key applications include underground parking garages, subway tunnels, basements, large-volume structures, and waterproof engineering. Compliant with CBMF 19-2017, available in R, M, S types with dosages of 6-10%.
Technical parameters
Original product values for technical screening.
Values are reproduced without keyword editing. Final selection must follow the current approved technical data sheet, test method and project conditions.
The source-page headings and values are retained as published. Do not interpret an unlabeled value as a guaranteed minimum.
| Test item | Indicator Requirements | |||
|---|---|---|---|---|
| — | Type R | Type M | Type S | |
| MgO content (%) | — | — | ≥80.0 | — |
| Loss on burnout (%) | — | — | ≤4.0 | — |
| Moisture content/% | — | — | 0.3 | — |
| Reaction time (s) | — | <100 | ≥100 and <200 | ≥200 and <300 |
| Fineness (%) | 80 μm square hole sieve 1.18 mm square hole sieve | — | 5.0 0.5 | — |
| Restriction on expansion (%) | 20℃ water 7d 20℃ water Δε 40℃ water 7d 40℃ water Δε | ≥0.020 ≥0.020 ≥0.040 ≥0.020 | 0.015 0.015 0.030 0.030 | 0.015 0.010 0.020 0.040 |
| Setting time (min) | Initial coagulation Final coagulation | ≥ ≤ | 45 600 | — |
| Compressive strength (MPa) | 7d 28d | ≥ ≤ | 22.5 42.5 | 22.5 42.5 |
Product usage
Application and installation guidance.
Magnesium Oxide (MgO) Shrinkage Reducing Admixture is perfect for concrete shrinkage compensation in waterproof and large-scale projects. Applications include underground parking, subway tunnels, civil defense, basements, large-volume pours, ultra-long structures, and special waterproof engineering. Usage Guidelines:
Mix at 6-10% of binder weight (≤9% max); select R/M/S type and test for specifics.
Mix at 6-10% of binder weight (≤9% max); select R/M/S type and test for specifics.
Ensure even mixing for optimal magnesium oxide expansive agent performance.
Ensure even mixing for optimal magnesium oxide expansive agent performance.
Cure for ≥7 days with moisture to activate crystals. Key Benefits: Achieves micro-expansion, prevents cracks, supports hydration and expansion in concrete. Follow CBMF 19-2017.
Cure for ≥7 days with moisture to activate crystals. Key Benefits: Achieves micro-expansion, prevents cracks, supports hydration and expansion in concrete. Follow CBMF 19-2017.
Technical enquiry
Check whether Magnesium Oxide (MgO) Shrinkage Reducing Admixture matches your project.
Include foundation type, grout geometry and volume, strength ages, flow requirement, temperature, standards, placement distance and equipment.