论文部分内容阅读
Scaling refers to a form of deterioration at the near surface of concrete, which experiences cycles of freezing and thawing in the presence of de-icing salt.The typical form of the damage involves mass loss as small chips or flakes of mortar spall away from the concrete surface, consequently exposing the aggregate.The carbonation of concrete is a process by which the carbon dioxide (CO2) from the atmosphere penetrates into the concrete from the surface and reacts with the cement hydration products,mainly calcium hydroxide and calcium silicate hydrates (C-S-H), to form calcium carbonate (CaCO3).Previous research has indicated that carbonation affects the salt-scaling resistance of concrete differently depending on the binder systems.This study aims to evaluate the effect of carbonation on near-surface properties of concrete including deicer scaling resistance and surface strength.A number of binders were studied including 100% ordinary Portland cement (OPC) and OPC incorporating different types of supplementary cementing materials (SCM) at various replacement levels.Concrete samples were exposed to different CO2 environments for various lengths of time after being initially cured for 14 days.Salt-scaling resistance of these concrete mixes were determined according to a standard salt-scaling test method.Furthermore, near-surface properties of concrete samples were also evaluated using an abrasion test method.