Americrete A-600 Gray Americrete Resurfacing Cement, 50 lb Bag. A-600 resurfacing cement is used to repair and resurface existing concrete surfaces over cracked, spalled, deteriorated masonry structures. This method of repair will create a slip resistant surface designed for heavy foot traffic and vehicular traffic. A-600 is easy to apply, dry-polymer and great for dry-climates. It is mostly used on decks, pools decks, walkways and for decorative overlays.