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Utilization of Phosphatic Clay Waste in Concrete



Phosphatic clay is a by-product of phosphate mining in Florida. This waste material occupies about 100,000 acres of land which could be utilized for other causes. Thus, its use as an alternating cementing material for the addition into the mixing matrix to yield high strength concrete would be a boon for both materials involved.

This project was designed to evaluate the feasibility of using dredged phosphatic waste in polymer modified hydrated cement paste and concrete from the chemistry, workability and mechanical properties points of view.

The results showed that phosphatic waste clay addition is capable of significantly improving the compressive strength of concrete. Combining the waste clay with a suitable polymer has the ability to dramatically improve the ductility of concrete. At this point, these two properties (strength and ductility) appear to represent a trade-off, only permitting the improvement of one at the expense of the other.

Though the potential of these systems is confirmed by this work, further research is necessary to optimize the interrelations between the constituents and to examine the long term effects of incorporating such materials into concrete.