Mechanics and Physics of Civil Engineering Materials

The lab seeks to understand and model the mesoscopic assembly and mechanical performance of reactive materials that are important to our built environment. Progress should enable new routes to optimize durable and eco-friendly designs. Our research is not confined to cement: it is interested in improving the design and functionality of civil engineering materials at large and is thus guided by several objectives: translating tools from electrochemistry and soft matter physics to cement and geomaterials to better understand chemical transport, microscopic organization, and mechanical behavior, utilizing data collected in experiments or in literature to validate predictions from our theory and models and identifying routes toward the preferred mesoscopic organization or composite assemblies that optimize the desired material trait and/or provide new functionality.

Here are two sample questions that interest us:

• How do geopolymers and colloidal cement particles aggregate and rigidify in a changing chemical environment? As we are now able to synthesize stable calcium-silicate-hydrate (C-S-H - the phase in cement that lends the material its cohesion) particles in solution, micro- and nanofluidic experiments offer a promising route to understanding aggregation mechanisms in precisely controlled electrochemical environments.

• How are the precipitation, aggregation, and ordering of colloidal and polymeric materials affected by their surrounding chemical environment? How do their hierarchical organizations influence their elasticity, toughness, and internal stress development? By extending phase-field descriptions to include electrostatic effects and incorporating the anisotropy of small-scale building blocks, combinatorial techniques and computer-aided design are hoped to improve our ability to translate observations made on the small scale (often nanometers) to the continuum micromechanical and macroscopic scales.

To achieve these research objectives, the lab is building experimental capability in measuring the transport properties of interacting colloidal particles - such as clays and varying geopolymers and nanocrystals. Experimental findings on the scale of micrometers and millimeters will be modeled using non-equilibrium thermodynamic theories, such as phase-field modeling and density functional theory. The goal is to connect microscopic ordering to properties development at the bulk scale and identify levers to tune properties.