About the research
Mixture proportioning generally uses a recipe based on a previously produced concrete, rather than adjusting the proportions based on the needs of the mixture and the locally available materials. As budgets grow tighter and environmental regulations increase, an emphasis on lowering the carbon footprint, is focusing attention on making mixtures that are more efficient in their usage of materials yet do not compromise engineering performance. A means of reducing environmental impact is to reduce the amount of binder in the mixture.
MnROAD is planning to construct several cells using reduced cementitious content mixtures, with the aim of monitoring the constructability and longevity of the concrete. The proposed work has been designed to identify the behavior and performance of concrete paving mixes with low cementitious content, i.e., between 475 to 500 lb/CY, and lower cementitious content, i.e., 430 to 470 lb/CY.
The objectives of this study included:
- Investigate the early-age characteristics (i.e., placement issues, slow strength gain) of concrete paving mixes containing low and lower cementitious content
- Assess causes of, or potential for, durability issues with very low cementitious content
- Identify effect of reduced cementitious content on long term serviceability and economics of concrete pavements (i.e., benefits of reduced shrinkage)
- Develop recommended specifications, mixing, and placement practices for the use of very low cementitious content concrete paving mixes