Description
RHEOMIX 720 is a liquid ultra stable 'micro' air entraining mortar plasticiser, designed to enhance the workability and freeze / thaw resistance of brick and block laying mortars. RHEOMIX 720 may be used to replace or supplement the use of lime, and is designed to cope with variations in cement and aggregate sources and quality.
Primary uses
RHEOMIX 720 is an admixture for mortars that improves the workability of bricklaying and plastering mortars and increases their resistance to freeze / thaw cycles. RHEOMIX 720 is particularly valuable in cold weather, for damp or exposed work, or when restricted site or safety conditions do not permit storage of lime.
Advantages
- Ultra stable bubble structure.
- Uniform air entrainment.
- Compatible with most types of Portland cement and difficult sands.
- Increased resistance to damage by freeze / thaw cycles.
- Reduced segregation and bleed.
- Greatly improved plasticity.
- Reduced permeability.
- Non corrosive to embedded metals.
- Easier and faster mortar spread.
- Fully compatible with mixes containing lime.
- Reduces incidence of efflorescence in mortar.
- Can be used to replace lime.
Packaging
RHEOMIX 720 is supplied in 210 litre containers or in bulk.
Standards
RHEOMIX 720 has been tested to comply with BS 4887, ASTM C91.
Action
RHEOMIX 720 replaces lime in the mix and reduces the amount of water required to achieve the required workability, thus reducing the possibility of drying shrinkage, which can result in cracking and crazing. Minute bubbles of air entrained in the hardened mortar provide space for the expansion of water when freezing occurs without disturbance to the body of the mortar.
Directions for use
RHEOMIX 720 may be either pre-mixed with the water or added directly into the mix at the same time as the water.
Note: The superior plasticising qualities of RHEOMIX 720 will result in a significant reduction in water demand of any given mix.
If hand mixing methods are used, a vigorous mixing action should be used to ensure efficient production of RHEOMIX 720 'micro' air entrainment properties.
Choice of relevant mix designs should be made in line with relevant British Standard Codes of Practice, Department of Environment Publications or relevant National Standards.
| Cement: Sand + RHEOMIX 720 |
Cement: Lime: Sand: |
Masonry Cement: Sand: |
Typical Uses |
| 1:3 |
1:¼:3 |
- |
Laying load-bearing brickwork. |
| 1:4½ |
1:½:4½ |
- |
External rendering (exposed conditions). Backing and bedding coats (rough cast). |
| 1:6 |
1:1:6 |
1:4½ |
Internal plaster floating coats. External rendering. |
| 1:3 to 1:6 |
Varies |
- |
Brickwork, pointing or re-pointing. |
| 1:8 |
1:2:9 |
1:6 |
Laying blocks and concrete or sand lime bricks. |
The action of RHEOMIX 720 is entirely physical. Used in accordance with instructions, it does not significantly affect the setting time or other properties of the mortar.
Watchpoints
RHEOMIX 720 provides protection from frost down to -2°C in the wet mortar. Therefore, RHEOMIX 720 should not be used at temperatures below -2°C or if the temperature is expected to drop below -2°C within 24 hours. Normal winter working precautions must be taken.
Dosage rate
RHEOMIX 720 is added at the rate of 150 to 250ml per 100kg of cement.
Compatibility
RHEOMIX 720 can be used with other admixtures provided these are added separately to the mix. It can be used for all types of Portland cement, including Sulphate Resisting. It can also be used in lime/sand mortars as a further precaution against frost.
Effects of over dosage
Whilst it is undesirable to exceed this stated dosage, the self-controlling action of RHEOMIX 720 limits the amount of air capable of being entrained, thus safeguarding against over dosage.
Specification clause
RHEOMIX 720:
All mortar and renders where indicated shall contain RHEOMIX 720 mortar plasticiser or similar approved. The plasticiser shall be based on synthetic or sustainable raw materials in an aqueous solution that provides stable and uniformly distributed air bubbles. The admixture shall comply with the requirements of BS 4887.
Storage
Store under cover, out of direct sunlight and protect from extremes of temperature.
Failure to comply with the recommended storage conditions may result in premature deterioration of the product or packaging. For specific storage advice consult BASF's Technical Services Department.
Safety precautions
RHEOMIX 720 contains no hazardous substances requiring labelling. For further information see material safety data sheet.
Note
Field service, where provided, does not constitute supervisory responsibility. For additional information contact your local BASF representative.
BASF reserves the right to have the true cause of any difficulty determined by accepted test methods.