Policymakers and politicians like to talk about creating infrastructure like roads, schools and transport systems: how it grows the economy, provides jobs, and strengthens domestic firms. But that infrastructure needs raw materials, people and constructors to create it. Martina Kirchberger of Trinity College Dublin is an expert on how stuff gets built in developing countries. Are the materials they need expensive? Will a construction boom also create jobs? Are there local firms who can do the work and, if not, who makes projects happen in the global construction sector? She talks to Tim Phillips about investment, partnership, and the surprising cost of cement.