Because Federal infrastructure projects create new National assets, they increase the net worth of the nation. When the net worth of any sovereign nation increases, it is possible for it to increase the money supply without inflationary risk. The increase should be exactly equivalent to the construction cost of the projects, and the new money should be used to fund the construction. Tax dollars, or borrowed funds, need not be used for any of these "hard asset" projects.
In this way, the nation creates new money in direct synch with national asset creation--which is not inflationary. This is the way out of the box we are currently trapped in. Because infrastructure projects, specifically, can be funded by "printing money" without inflation risk, there is no innate limitation to the funding that can be responsibly provided for such projects. (Of course, eventually one runs out of construction labor, but this is a problem we might like to have in America today as we slowly recover from the Great Recession.)
Literally, within the limits imposed by the size of the relevant labor force, the government could safely green-light all proposed infrastructure projects concurrently, and simply issue new funds to pay for them, without delay or triage. The resulting benefit to the economy, and to the capital strength of the nation, would be historic and revolutionary.
This may be nonintuitive, because corporations and individuals can't fund construction in this way. Corporations and people have to save, and/or borrow funds, to pay for projects. But sovereign nations operate at a higher level and have the unique ability to issue currency, to print money, to increase the money supply electronically. It is narrow, foolish, and wrong to think that we should limit the nation to the financing models that apply to individuals!
So the nation may provide limitless bounty for constructive activity, without collecting taxes, without borrowing, and without inflation, as long as the end result is a set of new, tangible national assets corresponding closely in value to the new money created. Of course, in such a system, depreciation must also be recognized by a regular, perhaps annual, reduction of the money supply in correspondence to the slow aging of dams, bridges, roads, and buildings.
This does not require a completely asset-based money supply. It only requires that one component of the money supply be locked in step with the increasing (or decreasing) value of hard national assets.