The research activities at concrete laboratory are focusing on concrete mechanics, including the quantitative analysis of concrete cracking. In 1999, this laboratory was designated as the national research laboratory for the control of concrete cracking. For the last five years, primary effort have been devoted to characterizing causes of concrete cracking and to developing crack-control system. This system is mainly composed of characterizing thermal/hygral/mechanical properties of concrete material and analyzing concrete structures considering concrete cracking induced by hydration heat, differential shrinkage, and environmental change in ambient temperature/humidity. Other interests of this laboratory include nonlinear analysis of concrete structures. Specific focuses have been placed on long-term behavior of concrete structures associated with creep, shrinkage, and autogenous shrinkage, which are applied to high-rise buildings and long-span bridges. In addition, fracture mechanics-based studies have been performed on cracking mechanism of concrete, size effect of concrete members, and development of ductile cementitious composites