Product Description
WRDA® 89 is an aqueous solution of modified lignosulfonates containing a catalyst which promotes more complete hydration of portland cement. It does not contain calcium chloride. WRDA 89 is manufactured under rigid control which provides uniform, predictable performance.
WRDA 89 is a chemical admixture meeting the requirements of the following chemical admixture specifications for concrete: BS 5075: Part 1; GB 8076-1997.
One litre weighs approximately 1.15kg ± 0.02kg.
Applications
WRDA 89 makes a workable mix with up to 10% less water and yields a stronger, less permeable and more durable concrete. 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.
Compared to other water reducers, WRDA 89 will typically impart the following additional benefits:
- More controlled set time (minimal retardation over a wide range of dosages)
- Higher ultimate compressive and flexural strengths
Chemical Action
As a dispersing agent, WRDA 89 lessens the natural interparticle attraction between cement grains in water. It does this by colloidal action, by absorption 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 89 effects a more complete hydration of the cement, beginning immediately after the cement and water come together at the lower additions of WRDA 89 or immediately after a period of designed and controlled hydration at the higher additions. WRDA 89 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
Addition Rates
WRDA 89 will provide water reduction with mild retardation as job conditions require. After a period of initial retardation at the higher addition rates, hydration continues rapidly and completely. The amount of WRDA 89 to be used will typically range from 200 to 600mL / 100kg of cementitious material depending upon job requirements. However, high addition rates may be used due to variations in cement, aggregate or other job site conditions