What was an innovation of the Romans?

Several things.

# Concrete. See http://en.wikipedia.org/wiki/Roman_cement

# First ball-bearings See http://www.open2.net/whattheancients/romans.html

# The personal calculator (OK the bronze hand abacus which took the form of a decimal place value system where each decade used a bi-quinary format.)

This means each column had two slots, the bottom with 4 beads, to top with one. Each of the four beads represented 1 of that column's value while the bead in the top slot counted five of the column's value. There were 7 columns for values of units, tens, hundreds, thousands, ten thousands, hundred thousands and millions.

there were also two columns for fractions based on twelfths and twelfths of twelfths. See http://www.hh.schule.de/metalltechnik-didaktik/users/luetjens/abakus/rom-abakus-en.htm but do not just accept the note that the bottom slot in the first column is for thirds of an uncia.. See also http://en.wikipedia.org/wiki/Roman_abacus which presents an alternative viewpoint for the bottom slot of column 1.

# Central heating. Underfloor and wall cavity hot air flow from a central oven. The underfloor heating was called a "hypocaust" and the wall cavities were created with baked clay tiles in the shape of a rectangular pipe. See http://en.wikipedia.org/wiki/Hypocaust

# Although aqueducts were probably used before the Romans, they took them to the pinnacle of capability, providing running water to Roman cities and running for many miles. Some of the water in Rome today is still supplied by the original pipes laid by the Romans. # Sewers. The Roman sewer system is still in use today. Called the "Cloaca Maxima". See http://en.wikipedia.org/wiki/Cloaca_Maxima Not much more, except about a third to half of English Words, the gift of 12 inches to a foot, the Word inch and ounce both from the Roman Word uncia which was 1/12 and the style of many of the western world's museums and town halls with columns and triangular lintels above the columns at the front.

So, not much.