Anything in the Sun will disappear rather rapidly.
DNA is amazing stuff, and will take advantage of any energy source. The stuff will break up concrete, asphalt, catalyze the corrosion of metals, it really works stuff over.
My guess is that within 50 years you couldn't see a highway or road from 500 feet above it. Dams would last a bit longer, as would high rise buildings, but they would soon be covered with various plant material. Fungi and lichens at first, followed by stuff with real roots.
Dust accumulates, and the burial process would also have an impact. If nothing else, a layer of 1/2 inch of dust and airborne debris will provide nourishment for a root system which would break up a lot of stuff.
Arf