This document specifies the standards for design and construction using the top-surface overlaying method, which increases the thickness of existing concrete members by integrating cementitious materials onto the top surface of the members so as to improve the safety, serviceability, durability and other properties of a concrete structure.

This document specifies structural intervention of existing concrete structures using cementitious materials design and execution principles, and strategies for defects and on-going deterioration including, but not limited to:

a)？mechanical actions, e.g. fatigue, impact, overloading, movement caused by settlement, blast, vibration, and seismic actions;

b)？chemical and biological actions from environments, e.g. sulfate attack, alkali-aggregate reaction;

c)？physical actions, e.g. freeze–thaw, thermal cracking, moisture movement, salt crystallization, fire, and erosion;

d)？reinforcement corrosion;

e)？original construction defects that remained unaddressed from the time of construction.