The water supply project will benefit 39mn people in São Paulo and part of Rio de Janeiro state.
The North American Development Bank agreed to provide US$36.5mn in financing for the facility's construction.
With plans for a new large-scale port in the city of San Antonio, provincial and city authorities want the Chilean government to speed up a tender for the concession of a road that is seen as key for the future port.
The US$78mn contract is part of a wider US$200mn plan to expand Port of Quequén's capacity.
Works on the highway started in 2001 but stopped two years later until the Macri administration restarted the project in 2016.
The Brazilian company is leading a consortium looking to build a hydroelectric dam in Tanzania.