SKIERNIEWICE, Poland—Chinese companies have wowed the world with superhighways, high-speed trains and snazzy airports, all built seemingly overnight. Yet a modest highway through Polish potato fields proved to be too much for one of China's biggest builders.

The A2 highway between Warsaw and Berlin was supposed to be an opportunity for Chinese construction to shine on a European stage after years of megaprojects at home and in the developing world. Poland badly wanted the project completed before the European soccer championships...