Ductal-Stretching the Performance and Durability of Concrete

Concrete has great compressive strength but poor tensile strength. It is brittle, cracks, and doesn’t flex, which is why it is reinforced with steel—but steel corrosion is a primary source of concrete failure. Lafarge’s Ductal line of specialty ultra-high-performance concretes (UHPC) offers significant improvements in these areas, with a thin, lightweight, extremely durable concrete avoiding standard steel reinforcement.

Ductal is made from portland cement, silica fume (a byproduct of electric arc furnaces), silica flour, silica sand, water, and polycarboxolate high-range water reducers (superplasticizers) that help cement flow; Lafarge adds metal or polyvinyl alcohol fibers to provide structure. “All the materials in Ductal are standard products,” said Vic Perry, vice president and general manager at Lafarge North America. “It’s how we select them and put them together that makes Ductal work.” Lafarge controls the size, geometry, and orientation of all the materials “at the micro level,” in Perry’s words, to create a very dense matrix that can be formed into intricate shapes while maintaining its performance.