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ConcreteConcreteConcrete is a mixture of sand and rock, held together with cement. Concrete is a mixture made up of water, sand, gravel, crushed stone, and cement. The ingredients are mixed together thoroughly, and are poured into a form. After the concrete is completely dry, it has excellent strength. Concrete Labs |
NSF Grant (DUE ATE 0501971) This grant is sponsored by the National Science Foundation’s Advanced Technology Education Program under Award No. 0501971