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We often finish new slabs with an acid etch. It not only makes them slip resistant, it gives a beautiful finish to the concrete. Wear protective clothing and boots, use a muratic acid wash till you get the cement paste burned off and begin to see the sand in the concrete, then rinse well with lots of water. A final rinsing with a baking soda solution will neutralize any remaining acid.
Sand blasting will give similar results though without the organic color of the acid etch and it is a lot more messy.