The IMF endorses the free-lunch view of infrastructure spending. That is, an IMF study suggests that the expansionary effects are sufficiently large that debt-financed infrastructure spending could reduce the debt-GDP ratio over time.
Certainly this outcome is theoretically possible (just like self-financing tax cuts), but you can count me as skeptical about how often it will occur in practice (just like self-financing tax cuts). The human tendency for wishful thinking and the desire to avoid hard tradeoffs are so common that it is dangerous for a prominent institution like the IMF to encourage free-lunch thinking.