WRDA® 35

Uses

WRDA® 35 produces a concrete with lower water content, greater plasticity and higher strength which is less permeable and more durable. It is used in ready-mix plants, job site plants and concrete pavers for normal weight and light weight concrete, in block, precast and prestressed concrete plants.

Performance

WRDA 35 is a chemical admixture meeting the requirements of Specification for Chemical Admixtures for Concrete, ASTM Designation C494 as a Type A and as a Type D admixture.

As a dispersing agent, WRDA 35 lessens the natural interparticle attraction between cement grains in water. It does this by colloidal action by adsorption on the cement particles thus reducing their tendency to clump together and makes the mix more workable with less water. As a cement catalyst, WRDA 35 affects a more complete hydration of the cement beginning immediately after the cement and water come together. This occurs at the lower additions of WRDA 35 or immediately after a period of designed and controlled hydration at the higher additions. WRDA 35 increases the gel content of the concrete, the paste or binder that “glues” the concrete aggregates together. The increased gel content adds to the water retention and internal cohesiveness of the mix, reducing bleeding and segregation as it increases workability and placeability.

Product Advantages

• Consistent water reduction and set times
• Improves performance concrete containing supplementary cementitious materials
• Produces concrete that is more workable, easy to place and finish
• High compressive and flexural strengths

Addition Rates

The amount of WRDA 35 to be used will range from 2 to 8 fl oz/ 100 lbs (130 to 520 mL/100 kg) of cement depending upon job requirements. ASTM C494 Type A performance is typically achieved when dosed from 2 to 5 fl oz/100 lbs (130 to 325 mL/100 kg) of cement and ASTM C494 Type D performance is typically achieved when dosed from 5 to 8 fl oz/100 lbs (325 to 520 mL/100 kg) of cement.

Compatibility with Other Admixtures and Batch Sequencing

WRDA 35 is compatible with most GCP admixtures as long as they are added separately to the concrete mix, usually through the water holding tank discharge line. In general, it is recommended that WRDA 35 be added to the concrete mix near the end of the batch sequence for optimum performance. Different sequencing may be used if local testing shows better performance. Please see GCP Technical Bulletin TB-0110, Admixture Dispenser Discharge Line Location and Sequencing for Concrete Batching Operations for further recommendations.