Scientists at Rice University have decoded the kinetic properties of cement and developed a way to “program” the microscopic, semicrystalline particles within. The process turns particles from disordered clumps into regimented cubes, spheres and other forms that combine to make the material less porous and more durable. The technique may lead to stronger structures that require less concrete. Worldwide production of more than 3 billion tons of concrete a year now emits as much as 10 percent of the carbon dioxide. For the first time, researchers synthesized C-S-H particles in a variety of shapes and mapped them into a unified morphology diagram for manufacturers and builders who wish to engineer concrete from the bottom up. Researchers call it ‘programmable cement’. The great advance of this work is that it is the first step in controlling the kinetics of cement to get desired shapes. The Rice lab created well-shaped cubes and rectangles by adding small amounts of positive or negative ionic surfactants and calcium silicate to C-S-H and exposing the mix to carbon dioxide and ultrasonic sound. The crystal seeds took shape around surfactant micelles within 25 minutes. Decreasing the calcium silicate yielded more spherical particles and smaller cubes, while increasing it formed clumped spheres and interlocking cubes. The strategies developed during the project could have implications for other applications including and refractory materials, bone tissue engineering, and could impact such other complex systems as ceramics and colloids.