WRDA® 25
Retarding Plasticizer for Ready Mix Concrete
Product Description
WRDA 25 is a liquid plasticizer for use wherever a delay in setting time will ensure sufficient time for delivery, placement, vibration or compaction particularly for:
Hot Weather Concreting
Where delayed set will assure sufficient placement times, and improve concrete quality.
Transit Mix Concrete
Where setting time on long hauls must be extended.
WRDA 25 complays with: EN 934, Part 2 Table 10 ASTM C 494 Type B and D.
Typical Properties
| Appearance | Dark Brown Liquid |
| Specific Gravity (20°C) | ca. 1.15 |
| Chloride Content | Nil |
| Air Entrainment | 1.0-2.0% |
| Freezing Point | 0°C |
Advantages
The use of WRDA 25 produces fresh concrete with goodplasticity and workability, easier to place and more finishable than a plain concrete or concretes treated with other admixtures.
WRDA 25 is also designed to delay and control the setting time of concrete. These features entail the following advantages:
At the same workability:
- At the usual addition rate the initial setting time of concrete will be extended by 4 to 8 hours at 20°C
- Water reduction provides strength increases at all ages
- Economy of mixing due to improvement in strength
- Improved impermeability and reduced shrinkage in the hardened concrete.
At the same water/cement ratio:
- Better control of hydration provides strength increases (5% to 15%) at all ages especially in hot weather oncreting
- Improved concrete flow over an untreated mix
- Better vibration response and finish
Addition Rates
Range
- 200 ml - 500 ml per 100 kg cement
- 0.20%-0.50% (v/w) by wt. of cement
As a guide to trials an addition rate of 0.30-0.40% volume by weight of cement is suggested.
For advice and assistance with trials we recommend that you consult GCP Applied Technologies.
Compatibility with Cements
WRDA 25 is compatible with all Portland, pozzolanic and blast furnace cements.
It is also compatible with concrete containing fly ash and or silica fume.
Compatibility with Admixtures
WRDA 25 is compatible with all GCP admixtures and particularly can be used in conjunction with airentraining agents. It is advisable to add all admixtures separately to a cementitious mix.
Method Of Use
WRDA 25 acts to optimize the rate and degree of hydration of the Portland cement in the concrete.
WRDA 25 also acts as a dispersing agent and lessens the natural interparticle attraction between cement grains in water.
The combination of water reduction and controlled hydration optimizes the rate of formation of gel, the paste that ‘glues’ or binds together the individual portions of the concrete aggregate.
This controlled rate of gel formation adds to the water retention and internal cohesiveness of the mix, reducing bleeding and segregation while increasing the workability, placeability and finishability of the concrete.
WRDA 25 while not reducing the total heat of hydration developed during the reaction of cement and water, does have a marked effect on the rate of heat evolution spreading it out over a longer time and reducing harmful shrinkage often found in hot weather concreting.
WRDA 25 is supplied ready for use. It should be added to the concrete mix during the mix process, at the same time as the water. It should not be added directly to the cement.
Effects of Overdosing
Overdosing of WRDA 25 will generally produce a considerable increase in workability and , in certain circumstances, a slight increase in air content.
The degree of overdose may also be accompanied by an increase in set retardation of both the initial and final set properties.
In such cases it is important to properly cure the concrete, to enable it to achieve its ultimate strength, which will generally be higher than that of normal concrete.
Dispensing
It is preferable that liquid admixtures for concrete should be introduced into a mixer by means of automatic dispensing equipment, details of which can be supplied upon request.
Health and Safety
For further information on Health and Safety matters regarding this product we recommend that you consult the relevant Material Safety Data Sheet from GCP.
Packaging and Storage
WRDA 25 is delivered ready to use in 220 kg drums.
Alternatively, bulk deliveries can be arranged.
WRDA 25 should be stored away from extremes of temperature and then protected from frost. The product should be kept out of direct sunlight in shaded storage at all times.
If the product does become frozen it should be carefully mixed after thawing out to restore it to its normal state.
Storage Life in Manufacturer’s Drums:
6 months from date of manufacture.
Storage Life in Bulk Storage:
6 months from date of delivery.
Technical Service
Our Technical Service department of GCP Applied Technologies is available to assist you in the correct use of our performance chemicals.
gcpat.it | Servizio clienti in Italia:: +39 02 93537291
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WRDA è un marchio commerciale, che può essere registrato negli Stati Uniti e/o in altri paesi, di GCP Applied Technologies, Inc.
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GCP Applied Technologies Inc., 2325 Lakeview Parkway, Alpharetta, GA 30009, USA
GCP Italiana S.p.A. - Via Trento, 7 - 20017 Passirana di Rho, Milano, Italy
Questo documento è aggiornato solo a partire dalla data dell’ultimo indicato di seguito ed è valido solo per l'uso in Italia. È importante consultare sempre le informazioni attualmente disponibili sull'URL.di seguito per avere le informazioni sul prodotto più recenti al momento dell'uso. Documenti aggiuntivi come i manuali di utilizzo, bollettini tecnici, disegni dettagliati e raccomandazioni dettagliate e altri documenti rilevanti sono disponibili anche su www.gcpat.fr. Le informazioni trovate su altri siti web non dovrebbero essere utilizzati, in quanto potrebbero non essere aggiornati o applicabili alle condizioni del tuo paese e non ci assumiamo alcuna responsabilità quanto al loro contenuto. In caso di conflitti o se hai bisogno di ulteriori informazioni, contatta il servizio clienti di GCP.
Last Updated: 2025-05-15
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