National Concrete Pavement Technology Center

Project description

VDOT has been requested to approve the use of locally produced cement with alkali content exceeding 1%. However, to prevent deleterious alkali-silica reaction (ASR), current VDOT specifications limit the alkali content of cement to 1%. A rational approach to allow for the use of cement with alkali content above 1% while preventing ASR is to consider the alkali loading in concrete (instead of solely focusing on the alkalis in the cement). Nonetheless, this approach is not presently considered in VDOT specifications. In addition, the performance-based ASR mitigation approach of the 2020 Virginia Road and Bridge Specifications relies on a withdrawn test procedure (ASTM C227). As a response, the main purpose of this study is to update ASR provisions in the Virginia Road and Bridge Specifications to: (1) consider the alkali loading in concrete; and (2) incorporate a currently acceptable ASR evaluation test method. In turn, this will help to more effectively mitigate the ASR distress and therefore increase the service life of concrete infrastructure in Virginia. Specifically, this study will evaluate the effect of cement alkali content, concrete alkali loading, and supplementary cementitious materials (SCMs) type and dosage on ASR in routine concrete mix designs used in VDOT projects.