I have used Traz25 to seal our outdoor concrete that was stained.
http://www.chemmasters.net/Products/Sealers/TDS/Traz%2025.pdf
Traz 25 is a film forming sealer for concrete and
masonry. Traz 25 is formulated with methyl methacrylate
polymers that develop high gloss and
are more chemical resistant than standard acrylic
sealers. The Traz 25 film will not yellow under
any UV conditions and is extremely durable.
USES
• Seal and protect any interior or exterior, horizontal
or vertical concrete and masonry surface
• Protect and amplify the beauty of exposed
aggregate, terrazzo and man-made or natural
stone
• Enhance and deepen the color of stamped
concrete while shielding it from water, freeze
thaw damage, dirt and most hydrocarbon chemicals
• Keeps surfaces from dusting and chalking
• Makes surfaces easier to clean