Nemati's main research interests include the investigation of the behavior of plain and reinforced concrete materials, and, in particular, the development of improved concrete materials and technologies for structural applications.  He has been active in the following research areas: fracture mechanics of concrete, application of stereology to analyze cracks in concrete, fracture analysis of concrete using scanning electron microscopy, effect of confinement on the fracture behavior of concrete, development of micromechanical models to simulate crack growth in concrete, accelerated construction techniques for pavements with Portland cement concrete, and using sea water as mixing water in concrete.